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An epidemiological investigation to determine the prevalence and clinical manifestations of slow-moving finished cattle presented to slaughter facilities

An epidemiological investigation to determine the prevalence and clinical manifestations of... An epidemiological investigation to determine the prevalence and clinical manifestations of slow-moving finished cattle presented to slaughter facilities †,2 ‡ ‖ † Tiffany L. Lee, Christopher D. Reinhardt, Steven J. Bartle, Erin F. Schwandt, ¶ § ¶ ¶ Michelle S. Calvo-Lorenzo, Christopher Vahl, Jacob A. Hagenmaier, Matthew J. Ritter, ¶ † Gary J. Vogel, and Daniel U. Thomson Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506; ‡ ‖ ¶ Reinhardt Nutrition Consulting, LLC, Katy, TX 77494; Bartle Consulting, Manhattan, KS 66502; Elanco Animal Health, Greenfield, IN 46140; Department of Statistics, Kansas State University, Manhattan, KS 66506 ABSTRACT: Cattle mobility is routinely measured was 97.02%, 2.69%, 0.27%, and 0.01%, respectively. at commercial slaughter facilities. However, the clin- Animals with an abnormal MS (MS > 1) were then ical signs and underlying causes of impaired mobil- assigned to one of five clinical observation catego - ity of cattle presented to slaughter facilities are ries: 1) lameness, 2) poor conformation, 3) laminitis, poorly defined. As such, the objectives of this study 4) Fatigued Cattle Syndrome (FCS), and 5) general were 1) to determine the prevalence of impaired stiffness. Of all cattle observed, 0.23% were catego- mobility in finished cattle using a 4-point mobility rized as lame, 0.20% as having poor conformation, scoring system and 2) to observe clinical signs in 0.72% as displaying signs of laminitis, 0.14% as order to provide clinical diagnoses for this subset of FCS, and 1.68% as showing general stiffness. The affected cattle. Finished beef cattle (n = 65,600) were prevalence of lameness and general stiffness was observed by a veterinarian during the morning shift greater in steers than heifers, whereas the prevalence from six commercial abattoirs dispersed across the of laminitis was the opposite (P < 0.05). FCS prev- United States; the veterinarian assigned mobility alence was higher in dairy cattle than in beef cat- scores (MS) to all animals using a 1–4 scale from the tle (0.31% vs. 0.22%, respectively; P ≤ 0.05). These North American Meat Institute’s Mobility Scoring data indicate the prevalence of cattle displaying System, with 1 = normal mobility and 4 = extremely abnormal mobility at slaughter is low and causes of limited mobility. Prevalence of MS 1, 2, 3, and 4 abnormal mobility are multifactorial. Key words: animal welfare, cattle mobility, Fatigued Cattle Syndrome, lameness © The Author(s) 2018. Published by Oxford University Press on behalf of the American Society of Animal Science. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non- Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com Transl. Anim. Sci. 2018.2:241–253 doi: 10.1093/tas/txy056 INTRODUCTION The mobility of finished cattle presented for Funding for this study was provided by Elanco Animal slaughter gained attention after an adverse animal Health, Greenfield, IN. 2 welfare event was reported in 2013, heightening Corresponding author: tlee@meatinstitute.org awareness of and concern about severe fatigue and Received January 8, 2018. Accepted April 26, 2018. its effects, a condition now defined as “Fatigued Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 242 Lee et al. Cattle Syndrome” (Vance, 2013; Thomson et  al., made during the months of April through August 2015). A  similar condition has been described in in 2016, and each facility was visited on five differ - swine where a portion of hogs exposed to stress ent weekdays throughout the summer so that scor- at the time of transport display decreased mobil- ing could be completed on each day of the business ity, and in extreme cases, become nonambulatory week (Monday through Friday). This approach as the result of metabolic acidosis and muscle was used to eliminate potential confounding effects fatigue (Ritter et  al., 2009). Reports of Fatigued of observing cattle on the same day over multiple Cattle Syndrome (FCS) typically occur in the hot weeks, as type and background of cattle may vary summer months and manifest with clinical signs within a week based on slaughter facility procure- such as tachypnea, muscle tremors, a stiff gait with ment strategies. shortened strides, reluctance to move, and in severe Weather measurements were obtained from cases, sloughing of the hoof wall (Thomson et al., the nearest local weather station at the beginning 2015; Frese et  al., 2016). Previous reports involv- and end of each shift and included ambient tem- ing cattle diagnosed with FCS describe radical ele- perature (°C), percent humidity, and wind speed vations in certain hematological variables such as (mph). The following information was recorded lactate, creatine kinase (CK), and aspartate ami- for each lot of cattle observed: feedlot of origin (to notransferase (AST) when compared with normal determine distance transported), slaughter facility reference ranges (Thomson et al., 2015). lot number, number of cattle in the lot, cattle type In 2015, the North American Meat Institute (beef or dairy), sex (categorized as steer, heifer, or (NAMI) adopted a 4-point mobility scoring system mixed), and distance transported. Flooring type of to complement other traditional scoring systems each facility was also recorded but not included in designed to assess the mobility of finished cattle the analysis, as only one facility used different floor - at commercial slaughter facilities (NAMI, 2015; ing. Temperature and humidity recorded at the end Edwards-Callaway et al., 2017) While mobility scor- of each shift were used to determine the day’s tem- ing is now common, efforts to define the etiologies perature–humidity index (THI), using the equation underlining finished cattle with abnormal mobility from Mader et al. (2010) where: at slaughter have not been made. It is unlikely that THI  =  (0.8  × ambient temperature in °C) + all cattle with abnormal mobility scores (MS) are [(% relative humidity/100) × (ambient temperature necessarily afflicted with FCS. Rather, some cattle in °C – 14.4)] + 46.4 may experience pain due to acute or chronic lame- Categories for ambient temperature, THI, and ness due to laminitis or other causes, which can be distance traveled were selected based on common amplified during the transport process ( Stokka et numeric categories, such as every 5  degrees, and al., 2001). Therefore, the objectives of this obser- every 100 miles. Time of observation was also vational study were to determine the prevalence recorded. Average lairage time for each lot was of cattle with abnormal mobility using the 4-point recorded and expressed as Lairage Time = time of mobility scoring system and to determine what observation−average of the times all trucks carry- clinical signs and/or pathology may contribute to ing the lot passed over the slaughter facility scale. abnormal mobility in finished cattle presented to This measurement therefore included the time cat- six commercial slaughter facilities across the United tle spent on the trucks waiting to be unloaded, time States. spent on the unloading dock, and time spent in lairage pens. Regardless of slaughter facility, cattle were MATERIALS AND METHODS observed between the hours of 0600 and 1600 (the All procedures were approved by the entirety of shift 1) after being removed from lairage Institutional Animal Care and Use Committee of pens, on their way to the serpentine alley that led Kansas State University (IACUC # 3708). to the restrainer. Observation locations were not Slaughter facilities were selected on the basis the same at each facility due to logistical consider- of 1) geographical location and 2) where historical ations; however, all observations were made at the data on cattle mobility were available. The six facil- same point of the animals’ drive from lairage pens ities selected were in different locations across the to the restrainer. The observer was trained using United States, and their operations reflect the cur - training videos provided by the NAMI (NAMI, rent population of finished cattle slaughtered in the 2015). An MS was assigned to each of the 65,600 United States, with each facility slaughtering over animals observed by the same trained veterinarian 1,500 cattle in a single 8-h shift. Observations were (T.L.L) using the scoring system adopted by the Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Prevalence of slow-moving finished cattle 243 NAMI (NAMI, 2015), where: 1  =  Normal, walks multivariable analyses were not performed; there- easily with no apparent lameness or change in gait; fore, no interactions or specific random effects were 2  =  Keeps up with normal cattle when the group included. The univariable analyses conducted were is walking, exhibits one or more of the following: to identify specific risk factors that may warrant stiffness, shortened stride, or slight limp; 3 = Lags further investigation. behind normal cattle when the group is walking, Each abnormal MS (i.e., MS 2, 3, and 4)  and exhibits one or more of the following: obvious each clinical diagnosis category (lameness, poor stiffness, difficulty taking steps, obvious limp, or conformation, laminitis, FCS, and general stiff- discomfort; 4 = Extremely reluctant to move, even ness) were considered dependent variables. Sex, when encouraged by handlers. Whereas cattle with breed, high ambient temperature, afternoon THI, normal mobility (MS = 1) were not uniquely iden- distance traveled, average lairage time, and time of tified, any animal receiving an MS ≥ 2 was con - observation were treated as independent variables. sidered to have impaired mobility and observed Comparisons of least square mean (LSMEAN) further by the same veterinarian who categorized estimates of the independent variables were made the observed clinical signs into one of the following between categories of each dependent variable five groups: 1)  lameness/injury other than lamini - using the LSMEANS procedure, with a Tukey– tis (lameness), 2)  poor conformation, 3)  laminitis, Kramer adjustment for multiple comparisons. The 4)  FCS, or 5)  general stiffness. Evidence of mus- count of the observations per group was assumed culoskeletal injury or disease was noted so that to follow a Poisson distribution, and the natural cases of lameness attributable to ailments such as logarithm of the cattle in the group was treated as infectious pododermatitis, fractures of the extrem- the offset (denominator) variable. An overdisper- ities, or broken hoof walls were combined into the sion term was included in the model to account for same lameness category (1). Cattle with abnor- within-group dependency of each outcome and to mal elongation of hooves, concavity of the dorsal inflate variance associated with the model estimates. hoof margin, and flattening/broadening of the sole Statistical significance was determined at P ≤ 0.05. were categorized as affected by chronic laminitis or founder (Boosman et  al., 1991, 2). Poor conform- RESULTS ation was defined with the use of the University of A total of 65,600 finished cattle were observed Arkansas’ Analysis of Beef Cattle Conformation at six slaughter facilities over 30 individual obser- and was characterized by abnormalities in shape or vation days, with steers (n  =  39,690) represent- structure of legs and feet (Barham et al., 3). Of par- ing more of the sample population than heifers ticular interest in the current study, the final two eti - (n = 19,734) and animals comprising lots of mixed ology categories described cattle without obvious sexes (n = 6,176) representing less than 10% of the disease or injury, which became reluctant to move sample population. These data reflect the current or failed to keep up with their contemporaries, and industry population of slaughtered steers and heif- had shortened strides, stiffened gait, and difficulty ers, in which steers represent approximately 55% of walking. Because acute signs of stress, including but the population and heifers represent approximately not limited to increased respiration rates, vocaliza- 25% (USDA AMS, 2017). There were a greater num- tion, severe stiffness, and muscle tremors, have been ber of beef breed cattle observed than cattle from described with cattle affected by FCS, the presence dairy breeds (n = 58,124 vs. 7,476, respectively). of these clinical signs was used to distinguish FCS Across observation days, the minimum temper- (4) from general stiffness (5). ature ranged from 3.8 °C to 22.2 °C, while the max- Data were entered and tabulated in a Microsoft imum temperature ranged from 18.9 °C to 37.2°C. Excel spreadsheet (Microsoft Excel® software, Distance traveled by cattle coming into the slaugh- Microsoft, Spokane, WA). Means, SDs, frequency ter facilities ranged from 8 to 1,917 km. Average distributions, and minimum and maximum values lairage time ranged from 30 min to over 12 h. In all for prevalence of MS and clinical diagnoses were but one facility, which had both grooved concrete calculated using spreadsheet formulas. Data were and rebar, grooved concrete was the flooring sur - further analyzed using the PROC GLIMMIX face in the lairage pens and alley ways. procedure to perform univariable analyses in SAS Overall, cattle receiving an MS  =  1 were most v.  9.4 (SAS Inst. Inc., Cary, NC). Because this is prevalent (97.02%; Table  1), cattle receiving an an exploratory prevalence study and the primary MS  =  4 were least prevalent (0.01%), and cattle objective was to determine the prevalence of and receiving MS 2 or 3 were intermediate (2.69% and clinical signs associated with abnormal mobility, Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 244 Lee et al. Table 1. Overall prevalence of MS 1, 2, 3, and 4 in 0.27%, respectively; Table 1). The total count of MS 65,600 finished cattle observed across six commer - in all cattle observed is summarized by sex and breed cial slaughter facilities in Table 2. Overall prevalence of each clinical obser- vation category and the proportion of each etiology MS* Count Percent % within the cattle observed are presented in Table  3. 1 63,647 97.02 Of the five clinical observation categories, general 2 1,767 2.69 stiffness represented the greatest proportion of cattle 3 180 0.27 with MS >1, with laminitis and lameness being the 4 6 0.01 next most common. When considering each MS >1, *MS was assigned to each animal observed using the scoring sys- general stiffness was the biggest contributor to preva- tem adopted by the NAMI, where: 1 = Normal, walks easily with no lence of animals displaying MS = 2 (Table 3), whereas apparent lameness or change in gait; 2  =  Keeps up with normal cat- tle when the group is walking, exhibits one or more of the following: the greatest proportion of cattle receiving MS 3 and 4 stiffness, shortened stride, or slight limp; 3 = Lags behind normal cat- displayed signs of FCS. Of all clinical signs observed tle when the group is walking, exhibits one or more of the following: in cattle displaying abnormal MS, shortened strides obvious stiffness, difficulty taking steps, obvious limp, or discomfort; and stiffness were most commonly reported (Table 4). 4 = Extremely reluctant to move, even when encouraged by handlers. Table 2. Total count of MS in 65,600 finished cattle summarized by sex and breed across six commercial slaughter facilities Beef Dairy* † ‡ MS Heifer Mixed lot Steer Heifer Mixed lot Steer 1 18,862 5,485 32,069 354 513 6,364 2 476 154 924 7 10 196 3 33 12 104 2 2 27 4 0 0 5 0 0 1 *MS was assigned to each animal observed using the scoring system adopted by the NAMI, where: 1 = Normal, walks easily with no apparent lameness or change in gait; 2 = Keeps up with normal cattle when the group is walking, exhibits one or more of the following: stiffness, shortened stride, or slight limp; 3 = Lags behind normal cattle when the group is walking, exhibits one or more of the following: obvious stiffness, difficulty taking steps, obvious limp, or discomfort; 4 = Extremely reluctant to move, even when encouraged by handlers. “Dairy” refers to Holstein animals. “Mixed lot” refers to animals which came in lots comprised of both heifers and steers. Table  3. Percentage of cattle displaying abnormal MS (MS ≥ 2)  categorized by clinical observation in 65,600 finished cattle across six commercial slaughter facilities MS* Clinical observation Total count 2 3 4 Percent of total observations % (n = 65,600) Lameness 153 132 19 2 0.23 Poor conformation 130 121 9 0 0.20 || Laminitis 471 423 47 1 0.72 FCS 94 1 90 3 0.14 General stiffness 1,105 1,090 15 0 1.68 *MS was assigned to each animal observed using the scoring system adopted by the NAMI, where: 1 = Normal, walks easily with no apparent lameness or change in gait; 2 = Keeps up with normal cattle when the group is walking, exhibits one or more of the following: stiffness, shortened stride, or slight limp; 3 = Lags behind normal cattle when the group is walking, exhibits one or more of the following: obvious stiffness, difficulty taking steps, obvious limp, or discomfort; 4 = Extremely reluctant to move, even when encouraged by handlers. Lameness/injury (other than laminitis) was defined as obvious lameness on one or more limbs caused by broken toes or legs, or any shoulder or rear leg injuries. Poor conformation was defined as abnormalities in shape or structure of legs and feet, which may affect cattle mobility. || Laminitis was defined as founder/laminitis including animals with abnormally long hooves, animals walking on their heels, presence of cracked hooves, concavity of the dorsal hoof margin, flattening/broadening of the sole, or possibly sloughed hoof walls. FCS was defined as animals displaying abnormal mobility, with clinical signs not due to injury or founder, including but not limited to nervous system abnormalities such as muscle tremors, increased respiratory rate, increased vocalization, obvious stiffness, and shortened strides. General stiffness was recorded when animals presented with abnormal mobility not due to any obvious disease, injury, or syndrome. Stiff cattle displayed normal behavior with the exception of abnormal mobility or range of movement. Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Prevalence of slow-moving finished cattle 245 Table 4. Number of cattle (n = 65,600) displaying clinical signs within each clinical observation category across six commercial slaughter facilities † || $ ¶ Lameness* Poor conformation Laminitis FCS General stiffness Clinical sign (n = 153) (n = 130) (n = 471) (n = 94) (n = 1,106) Lame 151 0 0 0 2 Broken leg 1 0 0 0 0 Broken toe 3 0 2 0 0 Sloughed hoof 0 0 0 0 0 Long toes 2 2 466 7 5 Shortened strides 10 105 420 92 1,004 Walking on heels 0 1 59 0 0 Increased respiratory rate 1 0 1 41 13 Muscle tremors 3 1 1 82 9 Stiffness 4 41 41 91 1,042 Vocalization 0 0 0 0 0 Nonambulatory 0 0 0 1 0 Clinical signs were not mutually exclusive. *Lameness/injury (other than laminitis) was defined as obvious lameness on one or more limbs caused by broken toes or legs, or any shoulder or rear leg injuries. Poor conformation was defined as abnormalities in shape or structure of legs and feet, which may affect cattle mobility. || Laminitis was defined as founder/laminitis including animals with abnormally long hooves, animals walking on their heels, presence of cracked hooves, concavity of the dorsal hoof margin, flattening/broadening of the sole, or possibly sloughed hoof walls. FCS was defined as animals displaying abnormal mobility, with clinical signs not due to injury or founder, including but not limited to nervous system abnormalities such as muscle tremors, increased respiratory rate, increased vocalization, obvious stiffness, and shortened strides. General stiffness was recorded when animals presented with abnormal mobility not due to any obvious disease, injury, or syndrome. Stiff cattle displayed normal behavior with the exception of abnormal mobility or range of movement. Lots comprised of steers exhibited a higher receiving abnormal MS across different times of prevalence of abnormal MS than lots comprised the shift when cattle were observed (P > 0.05). of heifers and animals from mixed lots (1.92% vs. Lameness was more prevalent in lots comprised 0.79% and 0.27%, respectively); however, no statis- of steers than lots comprised of heifers (P < 0.05), tically significant differences were detected between whereas no differences in the prevalence of lame- animals of different sexes within each abnormal ness were detected in lots of mixed sex when com- MS category (P > 0.05). There were no significant pared with lots of heifers or steers (P > 0.05, differences detected in the prevalence of abnor- respectively). Laminitis was more prevalent in heif- mal MS between breeds (P > 0.05). All animals ers than in steers (P < 0.05), but the prevalence of displaying MS  =  4 were steers, with five being of laminitis in mixed-sex lots was similar to that in lots beef breeds and one of dairy. Ambient temperature of heifers or steers (P < 0.05). A greater proportion and THI were not observed to have an effect on the of steers displayed general stiffness compared with prevalence of abnormal mobility (P > 0.05). heifers (P  <  0.05), but no difference was detected There was no observed effect of distance trans- when mixed lots were compared with lots of steers ported on the prevalence of MS 2 or 4 (Figure 1A or heifers (P > 0.05). There were no observed dif- and B; P > 0.05). On the other hand, the preva- ferences in the prevalence of poor conformation lence of cattle receiving an MS of 3 was lower in or FCS across lots of steers, heifers, and mixed lots shipped 0–161 km compared with 162–321 sex (P > 0.05). Prevalence of FCS was greater in km and 322–483 km (Figure  1B; P  =  0.0114 and dairy breeds compared with beef breeds (0.28% vs. 0.003, respectively), but no difference was observed 0.13%, respectively; P < 0.05; Table 5). However, no in prevalence of MS = 3 in cattle that had traveled effects of breed type on any of the other four clin- over 482 km (P > 0.05). Prevalence of MS 2 and 3 ical observation categories were observed. There increased as average lairage time increased up to 8 h were no differences detected for the prevalence of (P < 0.01, P < 0.01, respectively), then became more laminitis, FCS, or general stiffness across different variable up to and over 12  h (Figure  2B). There ambient temperatures (P > 0.05). Regarding THI, were no differences detected in MS = 4 at different the prevalence of lameness was greater at THIs average lairage times (P < 0.05). Additionally, there between 50 and 57.9 and 62 and 65.9 compared were no differences detected in prevalence of cattle with THIs of 66 to 69.9 (P < 0.05). No differences Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 246 Lee et al. Figure 1. Comparisons of point estimates for normal (A) and abnormal (B) MS prevalence categorized by distance traveled in 65,600 finished cattle at six commercial slaughter facilities. Variation is expressed as 95% CIs, and estimates for each MS without common superscripts differ (P ≤ 0.05). between the prevalence of laminitis were detected detected in the prevalence of lameness and poor across different levels of THI (P > 0.05). conformation with regards to lairage time (P > No differences were detected in prevalence of 0.05; Table 7). Prevalence of laminitis was greater lameness and poor conformation relative to dis- in animals experiencing a lairage time of 8–10 h tance transported (P > 0.05; Table  6); however, and >12  h compared with those spending 0–2  h distance transported impacted the proportion of in lairage (P  <  0.01), but no other differences cattle diagnosed with laminitis, FCS, and general were detected between any other two distance stiffness (P ≤ 0.05). Laminitis was more com- categories. Animals experiencing lairage times of mon in cattle transported 484–643 km compared 0–2 h displayed a lower prevalence of FCS than with those traveling 163–322 km (P  <  0.01), those in lairage for 4  h (P  <  0.01), but preva- but no differences in prevalence of laminitis lence of FCS did not appear to differ when these were detected when these animals were com- groups were compared with other lairage times. pared with animals traveling any other distance Prevalence of general stiffness was greatest at (P > 0.05). The prevalence of FCS was lower 4–6  h lairage (P  <  0.01). Animals experiencing in cattle transported 0–162 km vs. 323–482 km lairage times >10  h displayed greater prevalence (P < 0.01), but no differences in FCS prevalence of general stiffness than those in lairage for <4 h were observed between any other two distances (P  <  0.05). There were no differences detected (P > 0.05). General stiffness increased with dis- in the prevalence of laminitis, FCS, or general tance up to 482 km (P  <  0.01), after which no stiffness when compared across different times of differences were observed. No differences were observation (P < 0.05). Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Prevalence of slow-moving finished cattle 247 Figure  2. Comparison of point estimates for normal (A) and abnormal (B) MS prevalence categorized by average lairage time (h) in 65,600 finished cattle across six commercial slaughter facilities. Lairage time is defined as: Lairage Time = time of observation−average time the trucks car - rying the lot passed over the slaughter facility scale. Variation is expressed as 95% CIs and estimates without common superscripts differ (P ≤ 0.05). DISCUSSION typically occurs from 0600 to 1400 or 1500 h; there- fore, cattle were not observed in the hottest hours This study is the first to describe the prevalence of the day. Month of slaughter has been associated and clinical manifestations of impaired mobility in with increased mortality in finished cattle at the finished cattle presented to slaughter facilities in the feedyard (Loneragan et  al., 2014), but the contri- United States. While the prevalence of cattle receiv- bution of abnormal mobility to such mortality has ing an abnormal MS was relatively small (2.98%) not been explored. In addition, because observa- and the prevalence of abnormal scores decreased tions were made only in the late spring and summer with increasing severity, the subset of animals with months in this study, seasonal effects on the preva- impaired mobility present an animal welfare con- lence of abnormal MS could not be assessed. cern and warrant further discussion. This study Mader et  al. (2010) suggested incorporating helps identify potential risk factors contributing to solar radiation and wind speed into THI calcula- abnormal mobility and provides information upon tions; however, such information was used in assess- which future research studies can be designed. ments of environmental stress in feedyards, not in While some authors suggest that increased slaughter facilities. Although solar radiation likely ambient temperatures or seasonal changes cause contributes to the heat load experienced by cattle an increase in abnormal cattle mobility at slaughter temporarily held in slaughter facility lairage pens, facilities (Gonzalez et al., 2012a; Loneragan et al., wind may not be a major contributing factor in the 2014), there was no effect of temperature or THI ability of animals to cool themselves in such an on the proportion of abnormal MS assigned in this environment because the lairage pens at slaughter study. However, all observations in the current study facilities are relatively small with stocking densities were made during the first slaughter shift, which Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 248 Lee et al. much greater than feedyard pens, likely eliminating most of the positive impact wind may have on the cooling abilities of cattle. Shade has been shown to decrease heat stress in cattle in feedyards, but the use of shade in slaughter facility lairage pens has not been evaluated (Boyd et al., 2015). Shade struc- tures in lairage pens may in fact be detrimental to the animals’ ability to dissipate heat, as shade struc- tures may contribute to a further decrease in air flow throughout slaughter facility pens, but exploratory research into this hypothesis is needed. The prevalence of cattle receiving an MS  =  3 increased when distance transported to the slaugh- ter facility increased up to approximately 480 km (Figure  2B). In swine, losses due to deceased or nonambulatory pigs increase as distance moved during loading and distance traveled increase (Ritter et  al., 2007; Fitzgerald et  al., 2009). Data collected in this study indicate prevalence of abnor- mal mobility increases to a certain distance trav- eled and/or lairage time, then stays the same or decreases. Gonzalez et  al. (2012b) indicated that distance should be considered along with ambient temperature to mitigate the stress associated with transport; however, temperature was not recorded during transport in the current study. In the current study, further distances trans- ported and longer lairage times were associated with increased prevalence of FCS and general stiffness to a point (400 km distance, 8  h lai- rage), after which prevalence of each diagnosis decreased or stabilized. A substantial amount of research exists on the effects of distance traveled on stress and bruising in cattle, but such research does not include the assessment of cattle mobil- ity or the presence of any abnormalities other than biomarkers of stress, including blood cor- tisol, lactate, catecholamines, CK, and others (Mitchell, 1988; Jarvis et  al., 1995; Hoffman et al., 1998; Nanni Costa et al., 2003). In two sep- arate studies, Frese et al. (2016) and Hagenmaier et  al. (2017) reported that aggressive handling can increase stress markers such as lactate and CK in cattle and can have detrimental effects on mobility. Such associations between blood bio- markers and abnormal mobility are explored further in Lee et al. (unpublished data). High or inconsistent feed intake could con- tribute to differences in the prevalence of lamini- tis. Research shows that Charolais-cross cattle fed a high-concentrate diet for 142 d had a net sole horn growth of 2.5 times greater than that of cat- tle fed a high-concentrate diet for 30 fewer days (Greenough et  al., 1990). However, in the current Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Table  5. Comparison of point estimates clinical diagnosis prevalence categorized by breed in 65,600 finished cattle across six commercial slaughter facilities † || $ ¶ Lameness* Poor conformation Laminitis FCS General stiffness Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper Breed Estimate CL** CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value a a a a a Beef 0.22% 0.18% 0.28% 0.19% 0.15% 0.25% 0.73% 0.62% 0.85% 0.13% 0.09% 0.17% 1.67% 1.50% 1.87% 0.269 0.505 0.614 0.02 0.663 †† a a a b a Dairy 0.31% 0.18% 0.52% 0.24% 0.13% 0.44% 0.64% 0.40% 1.02% 0.28% 0.15% 0.51% 1.79% 1.33% 2.41% Estimates of the prevalence of each clinical observation category without common superscripts differ (P ≤ 0.05). *Lameness/injury (other than laminitis) was defined as obvious lameness on one or more limbs caused by broken toes or legs, or any shoulder or rear leg injuries. Poor conformation was defined as abnormalities in shape or structure of legs and feet, which may affect cattle mobility. || Laminitis was defined as founder/laminitis including animals with abnormally long hooves, animals walking on their heels, presence of cracked hooves concavity of the dorsal hoof margin, flattening/broad - ening of the sole, or possibly sloughed hoof walls. FCS was defined as animals displaying abnormal mobility, with clinical signs not due to injury or founder, including but not limited to nervous system abnormalities such as muscle tremors, increased res - piratory rate, increased vocalization, obvious stiffness, and shortened strides. General stiffness was recorded when animals presented with abnormal mobility not due to any obvious disease, injury, or syndrome. Stiff cattle displayed normal behavior with the exception of abnormal mobility or range of movement. **Confidence limit. †† “Dairy” refers to Holstein animals. Prevalence of slow-moving finished cattle 249 Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Table  6. Comparison of point estimates clinical diagnosis prevalence categorized by distance traveled in 65,600 finished cattle across six commercial slaughter facilities † || $ ¶ Lameness* Poor conformation Laminitis FCS General stiffness Distance Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper (km) Estimate CL** CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value a a ab a a 0–161 0.25% 0.19% 0.33% 0.20% 0.14% 0.28% 0.80% 0.66% 0.97% 0.07% 0.04% 0.13% 1.29% 1.10% 1.52% 0.798 0.436 0.045 0.008 0.0002 a a a ab b 162–321 0.22% 0.15% 0.32% 0.21% 0.14% 0.31% 0.54% 0.41% 0.73% 0.20% 0.12% 0.31% 1.95% 1.65% 2.29% a a ab b b 322–482 0.17% 0.07% 0.39% 0.13% 0.05% 0.36% 0.70% 0.42% 1.16% 0.39% 0.20% 0.74% 2.64% 2.00% 3.49% a a b ab ab 483–644 0.21% 0.03% 1.27% 0.53% 0.16% 1.77% 1.90% 0.91% 3.95% 0.00% 0.00% . 1.37% 0.54% 3.45% a a ab ab ab 645–805 0.10% 0.02% 0.59% 0.30% 0.10% 0.90% 0.70% 0.30% 1.60% 0.00% 0.00% . 1.79% 1.03% 3.11% a a ab ab ab >805 0.31% 0.15% 0.67% 0.08% 0.02% 0.41% 0.74% 0.40% 1.36% 0.23% 0.08% 0.61% 2.21% 1.52% 3.22% a-c Estimates of the prevalence of each clinical observation category without common superscripts differ (P ≤ 0.05). *Lameness/injury (other than laminitis) was defined as obvious lameness on one or more limbs caused by broken toes or legs, or any shoulder or rear leg injuries. Poor conformation was defined as abnormalities in shape or structure of legs and feet which may affect cattle mobility. || Laminitis was defined as founder/laminitis including animals with abnormally long hooves, animals walking on their heels, presence of cracked hooves, concavity of the dorsal hoof margin, flattening/ broadening of the sole, or possibly sloughed hoof walls. FCS was defined as animals displaying abnormal mobility, with clinical signs not due to injury or founder, including but not limited to nervous system abnormalities such as muscle tremors, increased res - piratory rate, increased vocalization, obvious stiffness, and shortened strides. General stiffness was recorded when animals presented with abnormal mobility not due to any obvious disease, injury, or syndrome. Stiff cattle displayed normal behavior with the exception of abnormal mobility or range of movement. **Confidence limit. 250 Lee et al. Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Table 7. Comparison of point estimates clinical observation prevalence categorized by average lairage time in 65,600 finished cattle across six commer - cial slaughter facilities † || $ ¶ Lameness* Poor conformation Laminitis FCS General stiffness Lairage time Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper (h) Estimate CL** CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value a a a a a 0 to 2 0.10% 0.04% 0.23% 0.10% 0.04% 0.23% 0.45% 0.27% 0.73% 0.03% 0.01% 0.18% 0.88% 0.62% 1.26% 0.313 0.03 0.056 0.016 <0.0001 a a ab ab ab 2 to 4 0.23% 0.17% 0.32% 0.16% 0.11% 0.23% 0.74% 0.60% 0.92% 0.10% 0.06% 0.18% 1.43% 1.22% 1.68% a a ab b c 4 to 6 0.21% 0.12% 0.35% 0.26% 0.17% 0.42% 0.62% 0.42% 0.91% 0.36% 0.23% 0.58% 2.76% 2.29% 3.34% a a ab ab abc 6 to 8 0.35% 0.15% 0.80% 0.43% 0.21% 0.90% 0.82% 0.42% 1.62% 0.00% 0.00% . 1.57% 0.95% 2.59% a a b ab abc 8 to 10 0.36% 0.13% 0.98% 0.48% 0.20% 1.14% 1.55% 0.84% 2.86% 0.24% 0.05% 1.10% 1.61% 0.88% 2.97% a a ab ab bc 10 to 12 0.24% 0.13% 0.47% 0.17% 0.08% 0.38% 0.66% 0.40% 1.10% 0.17% 0.07% 0.44% 2.01% 1.50% 2.70% a a b ab bc Over 12 0.31% 0.19% 0.52% 0.24% 0.14% 0.44% 0.94%a 0.64% 1.36% 0.15% 0.06% 0.36% 2.03% 1.56% 2.63% a-c Estimates of the prevalence of each clinical diagnosis without common superscripts differ (P ≤ 0.05). Lairage time is defined as Lairage Time = time of observation−average time the trucks carrying the lot passed over the slaughter facility scale. Variation is expressed as 95% CIs and estimates without common superscripts differ (P ≤ 0.05). *Lameness/injury (other than laminitis) was defined as obvious lameness on one or more limbs caused by broken toes or legs, or any shoulder or rear leg injuries. Poor conformation was defined as abnormalities in shape or structure of legs and feet, which may affect cattle mobility. || Laminitis was defined as founder/laminitis including animals with abnormally long hooves, animals walking on their heels, presence of cracked hooves, concavity of the dorsal hoof margin, flattening/ broadening of the sole, or possibly sloughed hoof walls. FCS was defined as animals displaying abnormal mobility, with clinical signs not due to injury or founder, including but not limited to nervous system abnormalities such as muscle tremors, increased res - piratory rate, increased vocalization, obvious stiffness, and shortened strides. General stiffness was recorded when animals presented with abnormal mobility not due to any obvious disease, injury, or syndrome. Stiff cattle displayed normal behavior with the exception of abnormal mobility or range of movement. **Confidence limit. Prevalence of slow-moving finished cattle 251 study, no difference in the prevalence of laminitis define the clinical diagnosis categories help to elim - in beef cattle is compared with that in dairy-breed inate some subjectivity. While the categories used cattle was observed, even though dairy-breed cattle to summarize clinical diagnoses of the abnormal- typically require a greater number of days on feed ities reported here are quite broad and animals than either steers or heifers of beef breeds (Mills entering the slaughter facility could have displayed et al., 1992). more specific problems than the ones reported here With regard to the increased proportion of (i.e., if a tumor affecting mobility was present on lameness and general stiffness observed in steers in an animal’s leg, the abnormality was classified as the current study, it could be hypothesized that steers “poor conformation” and a comment was made to are more prone to fighting and are more temper - note the presence of the tumor), these case defini - amental than their female counterparts, although tions capture the majority of pathologies that con- Voisinet et al. (1997) showed that heifers displayed tribute to decreased mobility in fed cattle. Despite greater temperament scores than steers. No data on some limitations, observational research, including temperament were collected in the current study, the current study, offers insight into issues that the therefore increased lameness and general stiffness industry encounters every day and serves as a plat- in steers cannot be attributed to temperament here. form upon which subsequent research can be based. Differences in prevalence of FCS or poor conform- After the adverse mobility events occurred dur- ation between sexes were not detected in this study. ing the summer of 2013 (Thomson et  al., 2015), Cattle of dairy breeds had a greater prevalence slaughter facilities began revisiting strategies to of FCS than beef breeds, possibly indicating they improve mobility and protect the welfare of cat- are more susceptible to the rigors of transport and tle presented for slaughter. Strategies implemented lairage processes. In addition to typically being fed thus far include communicating with feedyards higher concentrate diets earlier in life than their about incoming cattle conditions, making truck beef counterparts, dairy cattle require more time drivers and facility employees aware of the clinical to reach desirable end points for slaughter, result- signs of FCS, and contracting with feedyards which ing in longer days on feed (Mills et al., 1992). These employ mitigation strategies such as regular exer- factors could increase the risk of subclinical acid- cise, early detection of heat stress, and low-stress- osis and unobservable subclinical laminitis, and it handling techniques (Siemens and Alexander, is possible that such pathology could be mistaken personal communication [Cargill Meat Solutions, for fatigue (Greenough et  al., 1990). Finally, it Wichita, KS]). Identifying and implementing strat- has been proposed that responses to stress are the egies to help reduce the variability of cattle sources, result of a complex interaction between genetics handling practices, and transport practices can lead and previous experiences of the animals, but such to better health and well-being in all finished cattle relationships are not fully understood at this time transported to slaughter facilities. (Probst et al., 2014). Of the animals displaying MS ≥3, 50% were CONCLUSION diagnosed as having FCS. In hogs, approximately The information reported here is novel in the 50% of the nonambulatory animals are considered finished beef cattle industry. A sample of such mag - fatigued (Ritter et al., 2009). It should be noted that nitude is difficult to find in the literature, and much of the 65,600 animals observed in the current study, information can be gleaned from the observations only one animal was observed to be nonambula- made in this study, including the contributions of tory and the animal suffered from extreme fatigue. different clinical abnormalities to the mobility sta- When compared with earlier observational reports tus of cattle presented for slaughter. Measuring MS of increased prevalence of cattle displaying signs of and identifying the possible causes of decreased FCS, the syndrome does not seem to be as prevalent mobility can help producers further up the trans- as previously reported, based on the results of this port chain understand which practices to imple- study (Edwards-Callaway, 2013; Grandin, 2013). ment that will promote better health and mobility Inherently, there are limitations to any obser- of fed cattle presented to slaughter. For example, vational study. The use of subjective measurements widespread use of mitigation strategies such as reg- (MS and clinical diagnoses) allows for differences ular exercise and low-stress-handling techniques in opinion as to what constitutes the different levels may help address the most common mobility issue of mobility. However, the use of the same trained encountered in this study (general stiffness), which observer on each day and the use of a mobil- is similar to the approach and strategies used to ity scoring system and specific case definitions to Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 252 Lee et al. transport conditions and welfare outcomes during address the prevalence of FCS. Further research commercial long haul transport of cattle in North is needed to more fully explore the risk factors America. J. Anim. 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An epidemiological investigation to determine the prevalence and clinical manifestations of slow-moving finished cattle presented to slaughter facilities

Translational Animal Science , Volume 2 (3) – Sep 1, 2018
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Abstract

An epidemiological investigation to determine the prevalence and clinical manifestations of slow-moving finished cattle presented to slaughter facilities †,2 ‡ ‖ † Tiffany L. Lee, Christopher D. Reinhardt, Steven J. Bartle, Erin F. Schwandt, ¶ § ¶ ¶ Michelle S. Calvo-Lorenzo, Christopher Vahl, Jacob A. Hagenmaier, Matthew J. Ritter, ¶ † Gary J. Vogel, and Daniel U. Thomson Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506; ‡ ‖ ¶ Reinhardt Nutrition Consulting, LLC, Katy, TX 77494; Bartle Consulting, Manhattan, KS 66502; Elanco Animal Health, Greenfield, IN 46140; Department of Statistics, Kansas State University, Manhattan, KS 66506 ABSTRACT: Cattle mobility is routinely measured was 97.02%, 2.69%, 0.27%, and 0.01%, respectively. at commercial slaughter facilities. However, the clin- Animals with an abnormal MS (MS > 1) were then ical signs and underlying causes of impaired mobil- assigned to one of five clinical observation catego - ity of cattle presented to slaughter facilities are ries: 1) lameness, 2) poor conformation, 3) laminitis, poorly defined. As such, the objectives of this study 4) Fatigued Cattle Syndrome (FCS), and 5) general were 1) to determine the prevalence of impaired stiffness. Of all cattle observed, 0.23% were catego- mobility in finished cattle using a 4-point mobility rized as lame, 0.20% as having poor conformation, scoring system and 2) to observe clinical signs in 0.72% as displaying signs of laminitis, 0.14% as order to provide clinical diagnoses for this subset of FCS, and 1.68% as showing general stiffness. The affected cattle. Finished beef cattle (n = 65,600) were prevalence of lameness and general stiffness was observed by a veterinarian during the morning shift greater in steers than heifers, whereas the prevalence from six commercial abattoirs dispersed across the of laminitis was the opposite (P < 0.05). FCS prev- United States; the veterinarian assigned mobility alence was higher in dairy cattle than in beef cat- scores (MS) to all animals using a 1–4 scale from the tle (0.31% vs. 0.22%, respectively; P ≤ 0.05). These North American Meat Institute’s Mobility Scoring data indicate the prevalence of cattle displaying System, with 1 = normal mobility and 4 = extremely abnormal mobility at slaughter is low and causes of limited mobility. Prevalence of MS 1, 2, 3, and 4 abnormal mobility are multifactorial. Key words: animal welfare, cattle mobility, Fatigued Cattle Syndrome, lameness © The Author(s) 2018. Published by Oxford University Press on behalf of the American Society of Animal Science. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non- Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com Transl. Anim. Sci. 2018.2:241–253 doi: 10.1093/tas/txy056 INTRODUCTION The mobility of finished cattle presented for Funding for this study was provided by Elanco Animal slaughter gained attention after an adverse animal Health, Greenfield, IN. 2 welfare event was reported in 2013, heightening Corresponding author: tlee@meatinstitute.org awareness of and concern about severe fatigue and Received January 8, 2018. Accepted April 26, 2018. its effects, a condition now defined as “Fatigued Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 242 Lee et al. Cattle Syndrome” (Vance, 2013; Thomson et  al., made during the months of April through August 2015). A  similar condition has been described in in 2016, and each facility was visited on five differ - swine where a portion of hogs exposed to stress ent weekdays throughout the summer so that scor- at the time of transport display decreased mobil- ing could be completed on each day of the business ity, and in extreme cases, become nonambulatory week (Monday through Friday). This approach as the result of metabolic acidosis and muscle was used to eliminate potential confounding effects fatigue (Ritter et  al., 2009). Reports of Fatigued of observing cattle on the same day over multiple Cattle Syndrome (FCS) typically occur in the hot weeks, as type and background of cattle may vary summer months and manifest with clinical signs within a week based on slaughter facility procure- such as tachypnea, muscle tremors, a stiff gait with ment strategies. shortened strides, reluctance to move, and in severe Weather measurements were obtained from cases, sloughing of the hoof wall (Thomson et al., the nearest local weather station at the beginning 2015; Frese et  al., 2016). Previous reports involv- and end of each shift and included ambient tem- ing cattle diagnosed with FCS describe radical ele- perature (°C), percent humidity, and wind speed vations in certain hematological variables such as (mph). The following information was recorded lactate, creatine kinase (CK), and aspartate ami- for each lot of cattle observed: feedlot of origin (to notransferase (AST) when compared with normal determine distance transported), slaughter facility reference ranges (Thomson et al., 2015). lot number, number of cattle in the lot, cattle type In 2015, the North American Meat Institute (beef or dairy), sex (categorized as steer, heifer, or (NAMI) adopted a 4-point mobility scoring system mixed), and distance transported. Flooring type of to complement other traditional scoring systems each facility was also recorded but not included in designed to assess the mobility of finished cattle the analysis, as only one facility used different floor - at commercial slaughter facilities (NAMI, 2015; ing. Temperature and humidity recorded at the end Edwards-Callaway et al., 2017) While mobility scor- of each shift were used to determine the day’s tem- ing is now common, efforts to define the etiologies perature–humidity index (THI), using the equation underlining finished cattle with abnormal mobility from Mader et al. (2010) where: at slaughter have not been made. It is unlikely that THI  =  (0.8  × ambient temperature in °C) + all cattle with abnormal mobility scores (MS) are [(% relative humidity/100) × (ambient temperature necessarily afflicted with FCS. Rather, some cattle in °C – 14.4)] + 46.4 may experience pain due to acute or chronic lame- Categories for ambient temperature, THI, and ness due to laminitis or other causes, which can be distance traveled were selected based on common amplified during the transport process ( Stokka et numeric categories, such as every 5  degrees, and al., 2001). Therefore, the objectives of this obser- every 100 miles. Time of observation was also vational study were to determine the prevalence recorded. Average lairage time for each lot was of cattle with abnormal mobility using the 4-point recorded and expressed as Lairage Time = time of mobility scoring system and to determine what observation−average of the times all trucks carry- clinical signs and/or pathology may contribute to ing the lot passed over the slaughter facility scale. abnormal mobility in finished cattle presented to This measurement therefore included the time cat- six commercial slaughter facilities across the United tle spent on the trucks waiting to be unloaded, time States. spent on the unloading dock, and time spent in lairage pens. Regardless of slaughter facility, cattle were MATERIALS AND METHODS observed between the hours of 0600 and 1600 (the All procedures were approved by the entirety of shift 1) after being removed from lairage Institutional Animal Care and Use Committee of pens, on their way to the serpentine alley that led Kansas State University (IACUC # 3708). to the restrainer. Observation locations were not Slaughter facilities were selected on the basis the same at each facility due to logistical consider- of 1) geographical location and 2) where historical ations; however, all observations were made at the data on cattle mobility were available. The six facil- same point of the animals’ drive from lairage pens ities selected were in different locations across the to the restrainer. The observer was trained using United States, and their operations reflect the cur - training videos provided by the NAMI (NAMI, rent population of finished cattle slaughtered in the 2015). An MS was assigned to each of the 65,600 United States, with each facility slaughtering over animals observed by the same trained veterinarian 1,500 cattle in a single 8-h shift. Observations were (T.L.L) using the scoring system adopted by the Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Prevalence of slow-moving finished cattle 243 NAMI (NAMI, 2015), where: 1  =  Normal, walks multivariable analyses were not performed; there- easily with no apparent lameness or change in gait; fore, no interactions or specific random effects were 2  =  Keeps up with normal cattle when the group included. The univariable analyses conducted were is walking, exhibits one or more of the following: to identify specific risk factors that may warrant stiffness, shortened stride, or slight limp; 3 = Lags further investigation. behind normal cattle when the group is walking, Each abnormal MS (i.e., MS 2, 3, and 4)  and exhibits one or more of the following: obvious each clinical diagnosis category (lameness, poor stiffness, difficulty taking steps, obvious limp, or conformation, laminitis, FCS, and general stiff- discomfort; 4 = Extremely reluctant to move, even ness) were considered dependent variables. Sex, when encouraged by handlers. Whereas cattle with breed, high ambient temperature, afternoon THI, normal mobility (MS = 1) were not uniquely iden- distance traveled, average lairage time, and time of tified, any animal receiving an MS ≥ 2 was con - observation were treated as independent variables. sidered to have impaired mobility and observed Comparisons of least square mean (LSMEAN) further by the same veterinarian who categorized estimates of the independent variables were made the observed clinical signs into one of the following between categories of each dependent variable five groups: 1)  lameness/injury other than lamini - using the LSMEANS procedure, with a Tukey– tis (lameness), 2)  poor conformation, 3)  laminitis, Kramer adjustment for multiple comparisons. The 4)  FCS, or 5)  general stiffness. Evidence of mus- count of the observations per group was assumed culoskeletal injury or disease was noted so that to follow a Poisson distribution, and the natural cases of lameness attributable to ailments such as logarithm of the cattle in the group was treated as infectious pododermatitis, fractures of the extrem- the offset (denominator) variable. An overdisper- ities, or broken hoof walls were combined into the sion term was included in the model to account for same lameness category (1). Cattle with abnor- within-group dependency of each outcome and to mal elongation of hooves, concavity of the dorsal inflate variance associated with the model estimates. hoof margin, and flattening/broadening of the sole Statistical significance was determined at P ≤ 0.05. were categorized as affected by chronic laminitis or founder (Boosman et  al., 1991, 2). Poor conform- RESULTS ation was defined with the use of the University of A total of 65,600 finished cattle were observed Arkansas’ Analysis of Beef Cattle Conformation at six slaughter facilities over 30 individual obser- and was characterized by abnormalities in shape or vation days, with steers (n  =  39,690) represent- structure of legs and feet (Barham et al., 3). Of par- ing more of the sample population than heifers ticular interest in the current study, the final two eti - (n = 19,734) and animals comprising lots of mixed ology categories described cattle without obvious sexes (n = 6,176) representing less than 10% of the disease or injury, which became reluctant to move sample population. These data reflect the current or failed to keep up with their contemporaries, and industry population of slaughtered steers and heif- had shortened strides, stiffened gait, and difficulty ers, in which steers represent approximately 55% of walking. Because acute signs of stress, including but the population and heifers represent approximately not limited to increased respiration rates, vocaliza- 25% (USDA AMS, 2017). There were a greater num- tion, severe stiffness, and muscle tremors, have been ber of beef breed cattle observed than cattle from described with cattle affected by FCS, the presence dairy breeds (n = 58,124 vs. 7,476, respectively). of these clinical signs was used to distinguish FCS Across observation days, the minimum temper- (4) from general stiffness (5). ature ranged from 3.8 °C to 22.2 °C, while the max- Data were entered and tabulated in a Microsoft imum temperature ranged from 18.9 °C to 37.2°C. Excel spreadsheet (Microsoft Excel® software, Distance traveled by cattle coming into the slaugh- Microsoft, Spokane, WA). Means, SDs, frequency ter facilities ranged from 8 to 1,917 km. Average distributions, and minimum and maximum values lairage time ranged from 30 min to over 12 h. In all for prevalence of MS and clinical diagnoses were but one facility, which had both grooved concrete calculated using spreadsheet formulas. Data were and rebar, grooved concrete was the flooring sur - further analyzed using the PROC GLIMMIX face in the lairage pens and alley ways. procedure to perform univariable analyses in SAS Overall, cattle receiving an MS  =  1 were most v.  9.4 (SAS Inst. Inc., Cary, NC). Because this is prevalent (97.02%; Table  1), cattle receiving an an exploratory prevalence study and the primary MS  =  4 were least prevalent (0.01%), and cattle objective was to determine the prevalence of and receiving MS 2 or 3 were intermediate (2.69% and clinical signs associated with abnormal mobility, Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 244 Lee et al. Table 1. Overall prevalence of MS 1, 2, 3, and 4 in 0.27%, respectively; Table 1). The total count of MS 65,600 finished cattle observed across six commer - in all cattle observed is summarized by sex and breed cial slaughter facilities in Table 2. Overall prevalence of each clinical obser- vation category and the proportion of each etiology MS* Count Percent % within the cattle observed are presented in Table  3. 1 63,647 97.02 Of the five clinical observation categories, general 2 1,767 2.69 stiffness represented the greatest proportion of cattle 3 180 0.27 with MS >1, with laminitis and lameness being the 4 6 0.01 next most common. When considering each MS >1, *MS was assigned to each animal observed using the scoring sys- general stiffness was the biggest contributor to preva- tem adopted by the NAMI, where: 1 = Normal, walks easily with no lence of animals displaying MS = 2 (Table 3), whereas apparent lameness or change in gait; 2  =  Keeps up with normal cat- tle when the group is walking, exhibits one or more of the following: the greatest proportion of cattle receiving MS 3 and 4 stiffness, shortened stride, or slight limp; 3 = Lags behind normal cat- displayed signs of FCS. Of all clinical signs observed tle when the group is walking, exhibits one or more of the following: in cattle displaying abnormal MS, shortened strides obvious stiffness, difficulty taking steps, obvious limp, or discomfort; and stiffness were most commonly reported (Table 4). 4 = Extremely reluctant to move, even when encouraged by handlers. Table 2. Total count of MS in 65,600 finished cattle summarized by sex and breed across six commercial slaughter facilities Beef Dairy* † ‡ MS Heifer Mixed lot Steer Heifer Mixed lot Steer 1 18,862 5,485 32,069 354 513 6,364 2 476 154 924 7 10 196 3 33 12 104 2 2 27 4 0 0 5 0 0 1 *MS was assigned to each animal observed using the scoring system adopted by the NAMI, where: 1 = Normal, walks easily with no apparent lameness or change in gait; 2 = Keeps up with normal cattle when the group is walking, exhibits one or more of the following: stiffness, shortened stride, or slight limp; 3 = Lags behind normal cattle when the group is walking, exhibits one or more of the following: obvious stiffness, difficulty taking steps, obvious limp, or discomfort; 4 = Extremely reluctant to move, even when encouraged by handlers. “Dairy” refers to Holstein animals. “Mixed lot” refers to animals which came in lots comprised of both heifers and steers. Table  3. Percentage of cattle displaying abnormal MS (MS ≥ 2)  categorized by clinical observation in 65,600 finished cattle across six commercial slaughter facilities MS* Clinical observation Total count 2 3 4 Percent of total observations % (n = 65,600) Lameness 153 132 19 2 0.23 Poor conformation 130 121 9 0 0.20 || Laminitis 471 423 47 1 0.72 FCS 94 1 90 3 0.14 General stiffness 1,105 1,090 15 0 1.68 *MS was assigned to each animal observed using the scoring system adopted by the NAMI, where: 1 = Normal, walks easily with no apparent lameness or change in gait; 2 = Keeps up with normal cattle when the group is walking, exhibits one or more of the following: stiffness, shortened stride, or slight limp; 3 = Lags behind normal cattle when the group is walking, exhibits one or more of the following: obvious stiffness, difficulty taking steps, obvious limp, or discomfort; 4 = Extremely reluctant to move, even when encouraged by handlers. Lameness/injury (other than laminitis) was defined as obvious lameness on one or more limbs caused by broken toes or legs, or any shoulder or rear leg injuries. Poor conformation was defined as abnormalities in shape or structure of legs and feet, which may affect cattle mobility. || Laminitis was defined as founder/laminitis including animals with abnormally long hooves, animals walking on their heels, presence of cracked hooves, concavity of the dorsal hoof margin, flattening/broadening of the sole, or possibly sloughed hoof walls. FCS was defined as animals displaying abnormal mobility, with clinical signs not due to injury or founder, including but not limited to nervous system abnormalities such as muscle tremors, increased respiratory rate, increased vocalization, obvious stiffness, and shortened strides. General stiffness was recorded when animals presented with abnormal mobility not due to any obvious disease, injury, or syndrome. Stiff cattle displayed normal behavior with the exception of abnormal mobility or range of movement. Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Prevalence of slow-moving finished cattle 245 Table 4. Number of cattle (n = 65,600) displaying clinical signs within each clinical observation category across six commercial slaughter facilities † || $ ¶ Lameness* Poor conformation Laminitis FCS General stiffness Clinical sign (n = 153) (n = 130) (n = 471) (n = 94) (n = 1,106) Lame 151 0 0 0 2 Broken leg 1 0 0 0 0 Broken toe 3 0 2 0 0 Sloughed hoof 0 0 0 0 0 Long toes 2 2 466 7 5 Shortened strides 10 105 420 92 1,004 Walking on heels 0 1 59 0 0 Increased respiratory rate 1 0 1 41 13 Muscle tremors 3 1 1 82 9 Stiffness 4 41 41 91 1,042 Vocalization 0 0 0 0 0 Nonambulatory 0 0 0 1 0 Clinical signs were not mutually exclusive. *Lameness/injury (other than laminitis) was defined as obvious lameness on one or more limbs caused by broken toes or legs, or any shoulder or rear leg injuries. Poor conformation was defined as abnormalities in shape or structure of legs and feet, which may affect cattle mobility. || Laminitis was defined as founder/laminitis including animals with abnormally long hooves, animals walking on their heels, presence of cracked hooves, concavity of the dorsal hoof margin, flattening/broadening of the sole, or possibly sloughed hoof walls. FCS was defined as animals displaying abnormal mobility, with clinical signs not due to injury or founder, including but not limited to nervous system abnormalities such as muscle tremors, increased respiratory rate, increased vocalization, obvious stiffness, and shortened strides. General stiffness was recorded when animals presented with abnormal mobility not due to any obvious disease, injury, or syndrome. Stiff cattle displayed normal behavior with the exception of abnormal mobility or range of movement. Lots comprised of steers exhibited a higher receiving abnormal MS across different times of prevalence of abnormal MS than lots comprised the shift when cattle were observed (P > 0.05). of heifers and animals from mixed lots (1.92% vs. Lameness was more prevalent in lots comprised 0.79% and 0.27%, respectively); however, no statis- of steers than lots comprised of heifers (P < 0.05), tically significant differences were detected between whereas no differences in the prevalence of lame- animals of different sexes within each abnormal ness were detected in lots of mixed sex when com- MS category (P > 0.05). There were no significant pared with lots of heifers or steers (P > 0.05, differences detected in the prevalence of abnor- respectively). Laminitis was more prevalent in heif- mal MS between breeds (P > 0.05). All animals ers than in steers (P < 0.05), but the prevalence of displaying MS  =  4 were steers, with five being of laminitis in mixed-sex lots was similar to that in lots beef breeds and one of dairy. Ambient temperature of heifers or steers (P < 0.05). A greater proportion and THI were not observed to have an effect on the of steers displayed general stiffness compared with prevalence of abnormal mobility (P > 0.05). heifers (P  <  0.05), but no difference was detected There was no observed effect of distance trans- when mixed lots were compared with lots of steers ported on the prevalence of MS 2 or 4 (Figure 1A or heifers (P > 0.05). There were no observed dif- and B; P > 0.05). On the other hand, the preva- ferences in the prevalence of poor conformation lence of cattle receiving an MS of 3 was lower in or FCS across lots of steers, heifers, and mixed lots shipped 0–161 km compared with 162–321 sex (P > 0.05). Prevalence of FCS was greater in km and 322–483 km (Figure  1B; P  =  0.0114 and dairy breeds compared with beef breeds (0.28% vs. 0.003, respectively), but no difference was observed 0.13%, respectively; P < 0.05; Table 5). However, no in prevalence of MS = 3 in cattle that had traveled effects of breed type on any of the other four clin- over 482 km (P > 0.05). Prevalence of MS 2 and 3 ical observation categories were observed. There increased as average lairage time increased up to 8 h were no differences detected for the prevalence of (P < 0.01, P < 0.01, respectively), then became more laminitis, FCS, or general stiffness across different variable up to and over 12  h (Figure  2B). There ambient temperatures (P > 0.05). Regarding THI, were no differences detected in MS = 4 at different the prevalence of lameness was greater at THIs average lairage times (P < 0.05). Additionally, there between 50 and 57.9 and 62 and 65.9 compared were no differences detected in prevalence of cattle with THIs of 66 to 69.9 (P < 0.05). No differences Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 246 Lee et al. Figure 1. Comparisons of point estimates for normal (A) and abnormal (B) MS prevalence categorized by distance traveled in 65,600 finished cattle at six commercial slaughter facilities. Variation is expressed as 95% CIs, and estimates for each MS without common superscripts differ (P ≤ 0.05). between the prevalence of laminitis were detected detected in the prevalence of lameness and poor across different levels of THI (P > 0.05). conformation with regards to lairage time (P > No differences were detected in prevalence of 0.05; Table 7). Prevalence of laminitis was greater lameness and poor conformation relative to dis- in animals experiencing a lairage time of 8–10 h tance transported (P > 0.05; Table  6); however, and >12  h compared with those spending 0–2  h distance transported impacted the proportion of in lairage (P  <  0.01), but no other differences cattle diagnosed with laminitis, FCS, and general were detected between any other two distance stiffness (P ≤ 0.05). Laminitis was more com- categories. Animals experiencing lairage times of mon in cattle transported 484–643 km compared 0–2 h displayed a lower prevalence of FCS than with those traveling 163–322 km (P  <  0.01), those in lairage for 4  h (P  <  0.01), but preva- but no differences in prevalence of laminitis lence of FCS did not appear to differ when these were detected when these animals were com- groups were compared with other lairage times. pared with animals traveling any other distance Prevalence of general stiffness was greatest at (P > 0.05). The prevalence of FCS was lower 4–6  h lairage (P  <  0.01). Animals experiencing in cattle transported 0–162 km vs. 323–482 km lairage times >10  h displayed greater prevalence (P < 0.01), but no differences in FCS prevalence of general stiffness than those in lairage for <4 h were observed between any other two distances (P  <  0.05). There were no differences detected (P > 0.05). General stiffness increased with dis- in the prevalence of laminitis, FCS, or general tance up to 482 km (P  <  0.01), after which no stiffness when compared across different times of differences were observed. No differences were observation (P < 0.05). Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Prevalence of slow-moving finished cattle 247 Figure  2. Comparison of point estimates for normal (A) and abnormal (B) MS prevalence categorized by average lairage time (h) in 65,600 finished cattle across six commercial slaughter facilities. Lairage time is defined as: Lairage Time = time of observation−average time the trucks car - rying the lot passed over the slaughter facility scale. Variation is expressed as 95% CIs and estimates without common superscripts differ (P ≤ 0.05). DISCUSSION typically occurs from 0600 to 1400 or 1500 h; there- fore, cattle were not observed in the hottest hours This study is the first to describe the prevalence of the day. Month of slaughter has been associated and clinical manifestations of impaired mobility in with increased mortality in finished cattle at the finished cattle presented to slaughter facilities in the feedyard (Loneragan et  al., 2014), but the contri- United States. While the prevalence of cattle receiv- bution of abnormal mobility to such mortality has ing an abnormal MS was relatively small (2.98%) not been explored. In addition, because observa- and the prevalence of abnormal scores decreased tions were made only in the late spring and summer with increasing severity, the subset of animals with months in this study, seasonal effects on the preva- impaired mobility present an animal welfare con- lence of abnormal MS could not be assessed. cern and warrant further discussion. This study Mader et  al. (2010) suggested incorporating helps identify potential risk factors contributing to solar radiation and wind speed into THI calcula- abnormal mobility and provides information upon tions; however, such information was used in assess- which future research studies can be designed. ments of environmental stress in feedyards, not in While some authors suggest that increased slaughter facilities. Although solar radiation likely ambient temperatures or seasonal changes cause contributes to the heat load experienced by cattle an increase in abnormal cattle mobility at slaughter temporarily held in slaughter facility lairage pens, facilities (Gonzalez et al., 2012a; Loneragan et al., wind may not be a major contributing factor in the 2014), there was no effect of temperature or THI ability of animals to cool themselves in such an on the proportion of abnormal MS assigned in this environment because the lairage pens at slaughter study. However, all observations in the current study facilities are relatively small with stocking densities were made during the first slaughter shift, which Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 248 Lee et al. much greater than feedyard pens, likely eliminating most of the positive impact wind may have on the cooling abilities of cattle. Shade has been shown to decrease heat stress in cattle in feedyards, but the use of shade in slaughter facility lairage pens has not been evaluated (Boyd et al., 2015). Shade struc- tures in lairage pens may in fact be detrimental to the animals’ ability to dissipate heat, as shade struc- tures may contribute to a further decrease in air flow throughout slaughter facility pens, but exploratory research into this hypothesis is needed. The prevalence of cattle receiving an MS  =  3 increased when distance transported to the slaugh- ter facility increased up to approximately 480 km (Figure  2B). In swine, losses due to deceased or nonambulatory pigs increase as distance moved during loading and distance traveled increase (Ritter et  al., 2007; Fitzgerald et  al., 2009). Data collected in this study indicate prevalence of abnor- mal mobility increases to a certain distance trav- eled and/or lairage time, then stays the same or decreases. Gonzalez et  al. (2012b) indicated that distance should be considered along with ambient temperature to mitigate the stress associated with transport; however, temperature was not recorded during transport in the current study. In the current study, further distances trans- ported and longer lairage times were associated with increased prevalence of FCS and general stiffness to a point (400 km distance, 8  h lai- rage), after which prevalence of each diagnosis decreased or stabilized. A substantial amount of research exists on the effects of distance traveled on stress and bruising in cattle, but such research does not include the assessment of cattle mobil- ity or the presence of any abnormalities other than biomarkers of stress, including blood cor- tisol, lactate, catecholamines, CK, and others (Mitchell, 1988; Jarvis et  al., 1995; Hoffman et al., 1998; Nanni Costa et al., 2003). In two sep- arate studies, Frese et al. (2016) and Hagenmaier et  al. (2017) reported that aggressive handling can increase stress markers such as lactate and CK in cattle and can have detrimental effects on mobility. Such associations between blood bio- markers and abnormal mobility are explored further in Lee et al. (unpublished data). High or inconsistent feed intake could con- tribute to differences in the prevalence of lamini- tis. Research shows that Charolais-cross cattle fed a high-concentrate diet for 142 d had a net sole horn growth of 2.5 times greater than that of cat- tle fed a high-concentrate diet for 30 fewer days (Greenough et  al., 1990). However, in the current Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Table  5. Comparison of point estimates clinical diagnosis prevalence categorized by breed in 65,600 finished cattle across six commercial slaughter facilities † || $ ¶ Lameness* Poor conformation Laminitis FCS General stiffness Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper Breed Estimate CL** CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value a a a a a Beef 0.22% 0.18% 0.28% 0.19% 0.15% 0.25% 0.73% 0.62% 0.85% 0.13% 0.09% 0.17% 1.67% 1.50% 1.87% 0.269 0.505 0.614 0.02 0.663 †† a a a b a Dairy 0.31% 0.18% 0.52% 0.24% 0.13% 0.44% 0.64% 0.40% 1.02% 0.28% 0.15% 0.51% 1.79% 1.33% 2.41% Estimates of the prevalence of each clinical observation category without common superscripts differ (P ≤ 0.05). *Lameness/injury (other than laminitis) was defined as obvious lameness on one or more limbs caused by broken toes or legs, or any shoulder or rear leg injuries. Poor conformation was defined as abnormalities in shape or structure of legs and feet, which may affect cattle mobility. || Laminitis was defined as founder/laminitis including animals with abnormally long hooves, animals walking on their heels, presence of cracked hooves concavity of the dorsal hoof margin, flattening/broad - ening of the sole, or possibly sloughed hoof walls. FCS was defined as animals displaying abnormal mobility, with clinical signs not due to injury or founder, including but not limited to nervous system abnormalities such as muscle tremors, increased res - piratory rate, increased vocalization, obvious stiffness, and shortened strides. General stiffness was recorded when animals presented with abnormal mobility not due to any obvious disease, injury, or syndrome. Stiff cattle displayed normal behavior with the exception of abnormal mobility or range of movement. **Confidence limit. †† “Dairy” refers to Holstein animals. Prevalence of slow-moving finished cattle 249 Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Table  6. Comparison of point estimates clinical diagnosis prevalence categorized by distance traveled in 65,600 finished cattle across six commercial slaughter facilities † || $ ¶ Lameness* Poor conformation Laminitis FCS General stiffness Distance Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper (km) Estimate CL** CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value a a ab a a 0–161 0.25% 0.19% 0.33% 0.20% 0.14% 0.28% 0.80% 0.66% 0.97% 0.07% 0.04% 0.13% 1.29% 1.10% 1.52% 0.798 0.436 0.045 0.008 0.0002 a a a ab b 162–321 0.22% 0.15% 0.32% 0.21% 0.14% 0.31% 0.54% 0.41% 0.73% 0.20% 0.12% 0.31% 1.95% 1.65% 2.29% a a ab b b 322–482 0.17% 0.07% 0.39% 0.13% 0.05% 0.36% 0.70% 0.42% 1.16% 0.39% 0.20% 0.74% 2.64% 2.00% 3.49% a a b ab ab 483–644 0.21% 0.03% 1.27% 0.53% 0.16% 1.77% 1.90% 0.91% 3.95% 0.00% 0.00% . 1.37% 0.54% 3.45% a a ab ab ab 645–805 0.10% 0.02% 0.59% 0.30% 0.10% 0.90% 0.70% 0.30% 1.60% 0.00% 0.00% . 1.79% 1.03% 3.11% a a ab ab ab >805 0.31% 0.15% 0.67% 0.08% 0.02% 0.41% 0.74% 0.40% 1.36% 0.23% 0.08% 0.61% 2.21% 1.52% 3.22% a-c Estimates of the prevalence of each clinical observation category without common superscripts differ (P ≤ 0.05). *Lameness/injury (other than laminitis) was defined as obvious lameness on one or more limbs caused by broken toes or legs, or any shoulder or rear leg injuries. Poor conformation was defined as abnormalities in shape or structure of legs and feet which may affect cattle mobility. || Laminitis was defined as founder/laminitis including animals with abnormally long hooves, animals walking on their heels, presence of cracked hooves, concavity of the dorsal hoof margin, flattening/ broadening of the sole, or possibly sloughed hoof walls. FCS was defined as animals displaying abnormal mobility, with clinical signs not due to injury or founder, including but not limited to nervous system abnormalities such as muscle tremors, increased res - piratory rate, increased vocalization, obvious stiffness, and shortened strides. General stiffness was recorded when animals presented with abnormal mobility not due to any obvious disease, injury, or syndrome. Stiff cattle displayed normal behavior with the exception of abnormal mobility or range of movement. **Confidence limit. 250 Lee et al. Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 Table 7. Comparison of point estimates clinical observation prevalence categorized by average lairage time in 65,600 finished cattle across six commer - cial slaughter facilities † || $ ¶ Lameness* Poor conformation Laminitis FCS General stiffness Lairage time Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper (h) Estimate CL** CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value Estimate CL CL P value a a a a a 0 to 2 0.10% 0.04% 0.23% 0.10% 0.04% 0.23% 0.45% 0.27% 0.73% 0.03% 0.01% 0.18% 0.88% 0.62% 1.26% 0.313 0.03 0.056 0.016 <0.0001 a a ab ab ab 2 to 4 0.23% 0.17% 0.32% 0.16% 0.11% 0.23% 0.74% 0.60% 0.92% 0.10% 0.06% 0.18% 1.43% 1.22% 1.68% a a ab b c 4 to 6 0.21% 0.12% 0.35% 0.26% 0.17% 0.42% 0.62% 0.42% 0.91% 0.36% 0.23% 0.58% 2.76% 2.29% 3.34% a a ab ab abc 6 to 8 0.35% 0.15% 0.80% 0.43% 0.21% 0.90% 0.82% 0.42% 1.62% 0.00% 0.00% . 1.57% 0.95% 2.59% a a b ab abc 8 to 10 0.36% 0.13% 0.98% 0.48% 0.20% 1.14% 1.55% 0.84% 2.86% 0.24% 0.05% 1.10% 1.61% 0.88% 2.97% a a ab ab bc 10 to 12 0.24% 0.13% 0.47% 0.17% 0.08% 0.38% 0.66% 0.40% 1.10% 0.17% 0.07% 0.44% 2.01% 1.50% 2.70% a a b ab bc Over 12 0.31% 0.19% 0.52% 0.24% 0.14% 0.44% 0.94%a 0.64% 1.36% 0.15% 0.06% 0.36% 2.03% 1.56% 2.63% a-c Estimates of the prevalence of each clinical diagnosis without common superscripts differ (P ≤ 0.05). Lairage time is defined as Lairage Time = time of observation−average time the trucks carrying the lot passed over the slaughter facility scale. Variation is expressed as 95% CIs and estimates without common superscripts differ (P ≤ 0.05). *Lameness/injury (other than laminitis) was defined as obvious lameness on one or more limbs caused by broken toes or legs, or any shoulder or rear leg injuries. Poor conformation was defined as abnormalities in shape or structure of legs and feet, which may affect cattle mobility. || Laminitis was defined as founder/laminitis including animals with abnormally long hooves, animals walking on their heels, presence of cracked hooves, concavity of the dorsal hoof margin, flattening/ broadening of the sole, or possibly sloughed hoof walls. FCS was defined as animals displaying abnormal mobility, with clinical signs not due to injury or founder, including but not limited to nervous system abnormalities such as muscle tremors, increased res - piratory rate, increased vocalization, obvious stiffness, and shortened strides. General stiffness was recorded when animals presented with abnormal mobility not due to any obvious disease, injury, or syndrome. Stiff cattle displayed normal behavior with the exception of abnormal mobility or range of movement. **Confidence limit. Prevalence of slow-moving finished cattle 251 study, no difference in the prevalence of laminitis define the clinical diagnosis categories help to elim - in beef cattle is compared with that in dairy-breed inate some subjectivity. While the categories used cattle was observed, even though dairy-breed cattle to summarize clinical diagnoses of the abnormal- typically require a greater number of days on feed ities reported here are quite broad and animals than either steers or heifers of beef breeds (Mills entering the slaughter facility could have displayed et al., 1992). more specific problems than the ones reported here With regard to the increased proportion of (i.e., if a tumor affecting mobility was present on lameness and general stiffness observed in steers in an animal’s leg, the abnormality was classified as the current study, it could be hypothesized that steers “poor conformation” and a comment was made to are more prone to fighting and are more temper - note the presence of the tumor), these case defini - amental than their female counterparts, although tions capture the majority of pathologies that con- Voisinet et al. (1997) showed that heifers displayed tribute to decreased mobility in fed cattle. Despite greater temperament scores than steers. No data on some limitations, observational research, including temperament were collected in the current study, the current study, offers insight into issues that the therefore increased lameness and general stiffness industry encounters every day and serves as a plat- in steers cannot be attributed to temperament here. form upon which subsequent research can be based. Differences in prevalence of FCS or poor conform- After the adverse mobility events occurred dur- ation between sexes were not detected in this study. ing the summer of 2013 (Thomson et  al., 2015), Cattle of dairy breeds had a greater prevalence slaughter facilities began revisiting strategies to of FCS than beef breeds, possibly indicating they improve mobility and protect the welfare of cat- are more susceptible to the rigors of transport and tle presented for slaughter. Strategies implemented lairage processes. In addition to typically being fed thus far include communicating with feedyards higher concentrate diets earlier in life than their about incoming cattle conditions, making truck beef counterparts, dairy cattle require more time drivers and facility employees aware of the clinical to reach desirable end points for slaughter, result- signs of FCS, and contracting with feedyards which ing in longer days on feed (Mills et al., 1992). These employ mitigation strategies such as regular exer- factors could increase the risk of subclinical acid- cise, early detection of heat stress, and low-stress- osis and unobservable subclinical laminitis, and it handling techniques (Siemens and Alexander, is possible that such pathology could be mistaken personal communication [Cargill Meat Solutions, for fatigue (Greenough et  al., 1990). Finally, it Wichita, KS]). Identifying and implementing strat- has been proposed that responses to stress are the egies to help reduce the variability of cattle sources, result of a complex interaction between genetics handling practices, and transport practices can lead and previous experiences of the animals, but such to better health and well-being in all finished cattle relationships are not fully understood at this time transported to slaughter facilities. (Probst et al., 2014). Of the animals displaying MS ≥3, 50% were CONCLUSION diagnosed as having FCS. In hogs, approximately The information reported here is novel in the 50% of the nonambulatory animals are considered finished beef cattle industry. A sample of such mag - fatigued (Ritter et al., 2009). It should be noted that nitude is difficult to find in the literature, and much of the 65,600 animals observed in the current study, information can be gleaned from the observations only one animal was observed to be nonambula- made in this study, including the contributions of tory and the animal suffered from extreme fatigue. different clinical abnormalities to the mobility sta- When compared with earlier observational reports tus of cattle presented for slaughter. Measuring MS of increased prevalence of cattle displaying signs of and identifying the possible causes of decreased FCS, the syndrome does not seem to be as prevalent mobility can help producers further up the trans- as previously reported, based on the results of this port chain understand which practices to imple- study (Edwards-Callaway, 2013; Grandin, 2013). ment that will promote better health and mobility Inherently, there are limitations to any obser- of fed cattle presented to slaughter. For example, vational study. The use of subjective measurements widespread use of mitigation strategies such as reg- (MS and clinical diagnoses) allows for differences ular exercise and low-stress-handling techniques in opinion as to what constitutes the different levels may help address the most common mobility issue of mobility. However, the use of the same trained encountered in this study (general stiffness), which observer on each day and the use of a mobil- is similar to the approach and strategies used to ity scoring system and specific case definitions to Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/2/3/241/5035215 by Ed 'DeepDyve' Gillespie user on 31 July 2018 252 Lee et al. transport conditions and welfare outcomes during address the prevalence of FCS. Further research commercial long haul transport of cattle in North is needed to more fully explore the risk factors America. J. Anim. 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Journal

Translational Animal Science – Oxford University Press

Published: Sep 1, 2018

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