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Utilizing an electronic feeder to measure individual mineral intake, feeding behavior, and growth performance of cow–calf pairs grazing native range1

Utilizing an electronic feeder to measure individual mineral intake, feeding behavior, and growth... Utilizing an electronic feeder to measure individual mineral intake, feeding behavior, and growth performance of cow–calf pairs grazing native range †,2 ‡ ‡ †,3, Kacie L. McCarthy, Michael Undi, Stephanie Becker, and Carl R. Dahlen Department of Animal Sciences, North Dakota State University, Fargo, ND 58102, USA; and Central Grasslands Research Extension Center, North Dakota State University, Streeter, ND 58483, USA ABSTRACT:  Crossbred Angus cow–calf pairs (>90  g/d; average 125.4  g/d) and low (<90  g/d; (n = 28 pairs) at the Central Grasslands Research average 33.5  g/d) mineral intake was performed Extension Center (Streeter, ND) were used to using the GLM procedure. High-intake calves evaluate an electronic feeder to monitor indi- (>50  g/d; average 72.2  g/d) consumed greater vidual mineral intake and feeding behavior and (P < 0.001) amounts of minerals than low-intake their relationship with growth performance and calves (<50  g/d; average 22.2  g/d) intake calves. liver mineral concentrations. Cows and calves Cows and calves attended the mineral feeder a were fitted with radio frequency identification similar (P = 0.71) proportion of the days during ear tags that allowed access to an electronic the experiment (overall mean of 20%, or once feeder (SmartFeed system; C-Lock Inc., Rapid every 5 d). On days calves visited the feeder, they City, SD) and were provided ad libitum minerals consumed less (P  <  0.01) minerals than cows (Purina Wind and Rain Storm, Land O’Lakes, (222 ± 27 vs. 356 ± 26 g/d, respectively). Over the Inc., Arden Hills, MN). Mineral intake, number grazing period, calves gained 1.17  ± 0.02  kg/d, of visits, and duration at the feeder were re- whereas cows lost 0.35 ± 0.02 kg/d. Calf mineral corded over a 95-d monitoring period while intake was correlated with cow duration at the pairs were grazing native range. Liver biopsies mineral feeder (r  =  0.403, P = 0.05). Cows with were collected from a subset of cows on the high mineral intake had greater (P < 0.01) con- final day of monitoring and analyzed for min- centrations of Se (2.92 vs. 2.41 ug/g), Cu (247 vs. eral concentrations. Data were analyzed with the 116 ug/g), and Co (0.51 vs. 0.27 ug/g) compared GLM procedure in SAS for mineral intake and with low mineral intake cows, but liver concen- feeding behavior with age class (cows vs. calves), trations of Fe, Zn, Mo, and Mn did not differ intake category (high vs. low), and the inter- (P ≥ 0.22). We were able to successfully monitor action between class and category in the model. individual mineral intake and feeding behavior Correlations were calculated among cow feeding with the electronic feeder evaluated, and the di- behavior and calf intake and growth performance vergence in mineral intake observed with the with the CORR procedure, and a comparison of feeder was corroborated by concentrations of liver mineral concentrations among cows of high minerals in the liver. Key words: cow–calf, grazing, intake, mineral Authors would like to thank the North Dakota Agricul- the NDSU Nutrition Lab for their assistance with sample tural Experiment Station Precision Agriculture Fund and analysis. the North Dakota State Board of Agricultural Research and Present address: Department of Animal Science, Education Graduate Assistantship programs for their sup- University of Nebraska, Lincoln, NE 68583, USA port for this effort. Appreciation is also expressed to person- Corresponding author: carl.dahlen@ndsu.edu nel at the Central Grasslands Research and Extension Center Received October 26, 2020. for assistance with animal handling and forage collection and Accepted January 15, 2021. 1 McCarthy et al. © The Author(s) 2021. 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- NonCommercial 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. 2021.5:1-9 doi: 10.1093/tas/txab007 performance and concentrations of minerals in the INTRODUCTION liver. Mineral requirements of grazing cattle are not always satisfied by forages (McDowell, 1996); thus, MATERIALS AND METHODS mineral supplementation is often necessary to op- All animal procedures were approved by the timize animal health and performance (NASEM, Institutional Animal Care and Use Committee at 2016). An issue with providing mineral supple- North Dakota State University (A17064). ments to cattle, however, is the high degree of in- take variability associated with free-choice mineral supplements (Cockwill et al., 2000; Greene, 2000). Study Area Mineral intake variability is influenced by season, Research was conducted at the Central individual animal requirements, animal preference, Grasslands Research Extension Center, located availability of fresh minerals, mineral palatability, near Streeter, ND, from May 22, 2017 to September physical form of minerals, salt content of water, 27, 2017. This area is characterized by a contin- mineral delivery method, soil fertility and forage ental climate with warm summers and cold winters type, forage availability, animal social interactions, with a majority (72%) of precipitation occurring and likely other unknown factors (Bowman and between May and September (Limb et  al., 2018). Sowell, 1997; McDowell, 2003). August is the warmest month with a mean tempera- Providing free-choice mineral supplements to ture of 18.6  °C and January is the coldest month pasture-based cattle does not allow the measure- with an average low temperature of −15.3 °C (Fig. ment of individual animal mineral intake; as a re- 1; NDAWN, 2017). sult, mineral intake is measured on a group basis. The pasture was 62 ha with a stocking rate The measurement of individual animals’ mineral of 2.1 animal unit months/ha. The vegetation is supplement intake allows specific animal responses classified as mixed-grass prairie dominated by to be evaluated. Individual animal intake of free- western wheatgrass (Pascopyrum smithii [Rydb.] À. choice minerals is often variable due to the small amounts consumed (Tait and Fisher, 1996). The use of electronic monitoring systems in the beef in- dustry has been limited to systems primarily used in research settings to examine the effects on feed in- take in relation to cattle growth performance (Islas et  al., 2014), daily intake of salt-limited supple- ments (Reuter et al., 2017), health status (Wolfger et al., 2015), or animal movement in extensive pas- ture settings (Schauer et al., 2005). These technolo- gies could be adapted easily for use in beef cattle production systems to monitor activity, feeding, or drinking behavior or as tools for monitoring inven- tories in intensive or extensive production systems. Moreover, these technologies could be applied to target specific cow or calf supplementation strat- egies in pasture settings. Therefore, our objective Figure 1. Temperature and precipitation data from April to was to evaluate an electronic feeder to monitor October 2017 compared with 25-yr average. Data from North Dakota individual cow and calf mineral intake and feed- Agricultural Weather Network Station located in Streeter, ND ing behavior and their relationship with growth (NDAWN, 2017). Translate basic science to industry innovation Individual cow and calf mineral intake Löve), green needlegrass (Nassella viridula [Trin.] Table 1. Composition of mineral supplement con- Barkworth), and blue grama (Bouteloua graciles sumed by cow–calf pairs grazing native range; com- [Willd. ex Kunth] Lag. ex Griffiths). Other im- pany guaranteed analysis portant species present that are important drivers Item Min Max in biodiversity changes in the region include sedges Minerals (Carex spp.), prairie junegrass (Koeleria macrantha Ca, % 13.5 16.2 [Ledeb.] Schult.), sages (Artemisia spp.), and gold- P, % 7.5 – enrods (Solidago spp.), Kentucky bluegrass (Poa NaCl, % 18.0 21.6 pratensis L.) a nonnative grass, and western snow- Mg, % 1.0 – berry (Symphoricarpos occidentalis Hook.) a native K, % 1.0 – Mn, mg/kg 3,600 – shrub (Limb et al., 2018). Co, mg/kg 12 – Cu, mg/kg 1,200 – Electronic Feeder Device I, mg/kg 60 – Se, mg/kg 27 – The SmartFeed system (C-Lock, Inc., Rapid Zn, mg/kg 3,600 – City, SD) was used to deliver mineral supplement Vitamins, IU/kg and measure intake. The system features a stain- Vitamin A 661,500 – less-steel feed bin suspended on two load cells, a Vitamin D 66,150 – radio frequency identification (RFID) tag reader Vitamin E 661.5 – and antenna, an adjustable framework to allow ac- Purina Wind and Rain Storm Mineral (Land O’Lakes, Inc., Arden cess to one animal at a time, and a data acquisition Hills, MN). Ingredients: dicalcium phosphate, monocalcium phos- system that records RFID tags and feed bin weights phate, calcium carbonate, salt, processed grain byproducts, vegetable (Reuter et al., 2017). The electronic feeder was fas- fat, plant protein products, potassium chloride, magnesium oxide, natural and artificial flavors, calcium lignin sulfonate, ethoxyquin (a tened securely to the fence line to allow animal ac- preservative), manganese sulfate, zinc sulfate, basic copper chloride, cess to the feeder and restrict access to electrical ethylenediamine dihydroiodide, cobalt carbonate, vitamin A  supple- components and solar power source. The mineral ment (proprietary), vitamin E supplement (proprietary), and vitamin feeder was located down the fence line in a corner D3 supplement (proprietary). of the pasture 0.2 km away from the water source. started from initial pasture turn out (May 22, The feeder was covered with a plywood shell to pro- 2017) to June 22, 2017. Mineral intake, number of tect the feed bin and equipment from wind and rain. visits, time of visits, and duration at the feeder were Mineral disappearance in the feeder was monitored recorded continuously during a 95-d monitoring visually and through the online portal where intake period while pairs were grazing native range from and monitoring of the device were done remotely. June 23, 2017 to September 27, 2017. Daily mineral intake was calculated as the sum of individual feed- Animal Measurements ing events in each 24-h period and overall mineral intake was the sum of all feeding events during the Twenty-eight crossbred Angus based prim- 95-d monitoring period. The mean value for overall iparous cows [initial body weight (BW)  =  586  ± intake was used as an inflection point to categorize 52 kg] and their suckling calves (initial BW 113 ± cattle into mineral intake groups. Cows and calves 19  kg; 66  ± 8 d of age) were used to evaluate an were categorized into one of two mineral intake electronic feeder to monitor mineral intake and classifications: high (>90 or >50  g/d for cows and feeding behavior and their relationship with growth calves, respectively) and low (<90 or <50  g/d for performance and concentrations of minerals in the cows and calves, respectively) mineral intake during liver. The mean value of consecutive day weights of the 95-d monitoring period. cows and calves were used as initial and final BWs, with single-day BWs collected at 28-d intervals. Cows and calves were fitted with RFID ear tags Liver Sample Collection and Analysis that allowed access to the electronic feeder, which contained free-choice loose minerals (Purina Wind Samples of liver were collected on day 95 and Rain Storm, Land O’Lakes, Inc., Arden Hills, via biopsy from a subset of cows (n  =  18) with MN; Table 1). the greatest and least attendance at the mineral The SmartFeed unit was set in training mode feeder throughout the grazing period. Cows were (lowest locked setting to allow for ad libitum ac- restrained in a squeeze chute, and the hair be- cess to the feeder) and training cattle to the feeders tween the 10th and 12th ribs was clipped with Translate basic science to industry innovation McCarthy et al. size 40 blades (Oster; Sunbeam Products Inc., CP calculation. Neutral detergent fiber (NDF) and Boca Raton, FL). Liver biopsy samples (approxi- acid detergent fiber (ADF) concentrations were de- mately 20  mg) were collected using the method termined by the modified method of Van Soest et al. of Engle and Spears (2000) with the modifica- (1991) using a fiber analyzer (Ankom Technology tions that all heifers were given 3  mL Lidocaine Corp., Fairport, NY). Samples were also analyzed Injectable-2% (MWI, Boise, ID) with 1.5  mL for Cu, Zn, Co, Mo, Fe, S, and Se using inductively subcutaneously and 1.5  mL into the intercostal coupled plasma optical emission spectroscopy by muscles at the target biopsy site. An imaginary the Veterinary Diagnostic Laboratory at Michigan line is drawn from the tuber coxae (hook) to the State University. elbow. At the intersection with a line drawn hori- zontally from the greater trochanter, a stab inci- Statistical Analysis sion was then made between the 10th intercostal Data were analyzed using the GLM procedure space. A  core sample of the liver was taken via of SAS (SAS 9.4; SAS Inst. Inc., Cary, NC) with the Tru-Cut biopsy trochar (14 g; Merit Medical, mineral intake and feeding behavior compared South Jordan, UT). The liver sample was blotted among cows and calves. Mineral intake, feeding dry on ashless filter paper (Whatman 541 behavior, and performance were analyzed by age Hardened Ashless Filter Papers, GE Healthcare class (cows vs. calves), intake category (high vs. Bio-Sciences, Pittsburg, PA) and then stored in low), and the interaction between class and cat- tubes designed for trace mineral analysis (potas- egory. Correlations were generated among cows sium Ethylenediaminetetraacetic acid; Becton and calves with the variables cow duration at the Dickinson Co., Franklin Lakes, NJ) and stored feeder, intake, and BW and calf average daily gain, at −20  °C until further analysis. After obtaining intake, and duration at the feeder using the CORR liver biopsies, a staple (Disposable Skin Staple 35 procedure of SAS. Comparisons of liver mineral Wide; Amerisource Bergen, Chesterbrook, PA) concentrations among cows of high (>90 g/d) and and topical antibiotic (Aluspray; Neogen Animal low (<90  g/d) mineral intake were analyzed with Safety, Lexington, KY) was applied to the sur- PROC GLM. For all analyses, significance was set gical site and an injectable Nonsteroidal Anti- at P ≤ 0.05. inflammatory Drug (Banamine; Merck Animal Health, Madison, NJ) was given intravenously at RESULTS AND DISCUSSION 1.1 mg/kg of BW. Liver samples were sent to the Veterinary Diagnostic Laboratory at Michigan State University and were evaluated for concen- Mineral Intake and Feeding Behavior trations of minerals using inductively coupled Over the duration of the 95-d grazing period, plasma mass spectrometry. cows consumed more (P  <  0.001; Table 2) min- erals than calves. An age class × mineral intake category interaction (P  =  0.005) was detected Forage Collection and Analysis for intake over the 95-d monitoring period, with Forage samples were obtained every 2 wk from high-intake cows having greater mineral con- 10 different locations in the pasture in a diagonal sumption (125.4  g/d; P  <  0.001) compared with line across the pasture. The forage samples were high-intake calves (72.2  g/d), which were greater hand clipped to a height of 3.75 cm above ground (P < 0.001) than low-intake cows and calves (33.5 (Undi et al., 2008). Forage samples were dried in a vs. 22.2 g/d, respectively). Generally, cattle mineral forced-air oven at 60 °C for at least 48 h and then formulations are designed to fall within the tar- ground to pass through a 2-mm screen using a geted intake of between 56 and 114 g/d per animal Wiley mill (Arthur H. Thomas, Philadelphia, PA). for free-choice mineral supplementation (Greene, Clipped forage samples for each location reported 2000). Variability in feeder attendance and daily herein are composite over all locations within the mineral intake by individual cattle utilizing other representative sampling date. Forage samples were electronic feeders have been reported by multiple analyzed at the North Dakota State University research groups (Cockwill et  al., 2000; Manzano Nutrition Laboratory for dry matter (DM), crude et  al, 2012; Patterson et  al., 2013). Furthermore, protein (CP), ash, N (Kjehldahl method), Ca, P, Patterson et  al. (2013) evaluated cows and their and ether extract (EE) by standard procedures calves using a Calan gate feeder system and pro- (AOAC, 1990). Multiplying N by 6.25 determined vided three different supplemental sources of Se Translate basic science to industry innovation Individual cow and calf mineral intake Table 2. Mineral intake and feeding behavior of grazing cow–calf pairs on native range utilizing an elec- tronic feeder a b Calves Cows P-value Item High Low High Low SEM Age class Intake category Class × Category c b c a c 95 d intake , g/d 72.2 22.2 125.4 33.5 5.7 <0.001 <0.001 0.005 Days eating, % 27.5 14.5 27.5 14.5 1.4 0.83 <0.001 0.64 d b c a b Intake , g/d 300.1 161.2 461.8 242.5 28.1 <0.001 <0.001 0.005 Time , min 147.3 57.2 118.4 39.4 9.3 0.02 <0.001 0.56 Eating rate, g/min 49.4 39.2 106.6 74.8 7.3 <0.001 <0.006 0.14 abc Means within row lacking common superscript differ (P < 0.05). Calf divergent mineral intake classified calves as high (>50 g/d) or low (<50 g/d) mineral intake. Cow divergent mineral intake classified cows as high (>90 g/d) or low (<90 g/d) mineral intake. Represents average daily intake over the course of the 95-d monitoring period. Represents daily intake on the days cows and calves attended the electronic feeder. Time represents the total time in minutes spent at the feeder over the course of the 95-d monitoring period. during a year-long production regimen and also re- time at the feeder resulted in a slower overall rate ported variability with intakes ranging from 27.9 of mineral consumption for calves compared with to 97.3  g/d with a mean mineral consumption of cows (P  <  0.0001), and high-intake animals ate 54  g/d. However, calf intake was not evaluated in faster (P < 0.006) than low-intake animals. It is im- Patterson et al. (2013). Compared to utilizing elec- portant to note that both classes of cattle attended tronic feeders, Pehrson et al. (1999) provided min- the mineral feeders for a similar (P = 0.71) propor- eral supplement in a wooden box to grazing cows for tion of days during the experiment (overall mean an 80-d period and calculated the mean daily sup- of only 20% or once every 5  days). Interestingly plement consumption by dividing the total amount though, mean intake values for cows and calves of feed by the number of animals consuming it, over the course of the experiment did not meet with the assumption that calves did not consume manufacturers’ feeding recommendation (113.4  g) any significant amount. Thus, Pehrson et al. (1999) for the minerals used because the cattle did not estimated that the daily consumption for Se yeast visit the feeders every day but the mineral intake of mineral supplement was 110  g/cow, whereas cows both cows and calves exceeded the manufacturers supplemented with selenite consumed 107  g/cow. feeding recommendation on days they did visit the Our group was able to use the SmartFeed system feeders. to evaluate the mineral intake of cow–calf pairs on Mineral intake on the days cows and calves pasture and record individual intakes of calves that visited the mineral feeders was impacted by an age the aforementioned groups were unable to evaluate. class × intake category interactions (P  =  0.005), The observation of high-intake calves consuming with high-intake cows consuming more (P < 0.001) more minerals than low-intake cows reveals the im- minerals (461.8  g/d) than low-intake cows portance of considering calf intake when making (242.5  g/d) and high-intake calves (300.1  g/d), decisions about the amount of supplement to be which consumed more (P < 0.001) than low-intake offered or interpreting mineral disappearance in calves (161.2  g/d). Cockwill et  al. (2000) reported pastures where cow–calf pairs are grazing. high variability of mineral intake over a 6-d grazing No class × category interactions (P > 0.14) period with individual intakes among cows and were present in the proportion of days cattle con- calves ranging from 0 to 974 and 0 to 181 g/d, re- sumed mineral, time spent at the feeder, or eating spectively. Unfortunately, little field data exist for rate (Table 2). Furthermore, no differences were ob- individual free-choice mineral intake by cows and served for age class for the proportion of days at- calves managed under forage-based cow–calf regi- tending the feeder (P = 0.83); however, high-intake mens (Patterson et  al., 2013). The current experi- cattle spent a greater proportion of days consuming ment offers a glimpse of mineral intake variability minerals compared to low-intake cattle (P < 0.001). over a 3-month period in cows and calves grazing Overall, calves spent more time at the feeder com- the native range. pared to cows (P  <  0.001), and high-intake cows With the proportion of days during the experi- and calves spent more time at the mineral feeder ment that cattle were consuming minerals, the lo- than their low-intake counterparts (P = 0.02). The cation of the mineral feeder and grazing behavior reduced intake of calves combined with a longer may explain the variation in intake over the grazing Translate basic science to industry innovation McCarthy et al. period. It is probable that such distances from the decreasing in BW and body condition in a cyclic water source could also alter patterns of electronic pattern throughout the production year (NASEM, feeder attendance. Likewise, Smith et  al. (2016) 2016). Additionally, primiparous cows require add- reported that individual steers visited a mineral itional nutrient requirements for their own growth, feeder an average of 44.3% of the days monitored meeting nutrient requirements for lactation to sup- (90-d monitoring period) when the mineral feeder port an existing offspring, and overall maintenance was in immediate proximity to the water source. (Short et  al., 1990; Meek et  al., 1999; NASEM, In the current experiment, we did not implement 2016), which makes it hard to gain weight. a training period before pasture turnout; thus, the The amount of time cows spent at the mineral novelty of the feeder could have contributed to the feeder was positively correlated with cow mineral in- neophobic behavior of new feeding devices or feeds take (r = 0.923; P < 0.01; Table 4). Additionally, the (Bowman and Sowell, 1997). However, the training amount of time calves spent at the feeder was posi- period utilized in the experiment should have been tively correlated with calf mineral intake (r = 0.948; sufficient to overcome the neophobic behavior. P  <  0.01). The time cows spent at the feeder was Probably, the inability to move the feeder away also positively correlated with calf mineral intake from the corner of the pasture and closer to the (r  =  0.403; P  =  0.05). Similar findings have been water or increase cattle traffic influenced the pro- reported with inexperienced sheep increasing sup- portion of days the cattle attended the feeder. plement intake in the presence of more experienced sheep (Bowman and Sowell, 1997). Furthermore, cow starting BW was negatively correlated with the Cow and Calf Performance duration the calf spent at the feeder and calf intake There were no class by intake category inter- (r  =  −0.631 and −0.553, respectively; P  <  0.01). actions (P ≥ 0.53; Table 3) for cow and calf BWs This could suggest that as the grazing season pro- over the course of the monitoring period (Table 3). gressed, the cow’s milk production was declining Final BW for cows and calves were 568 ± 53 kg and because of the normal lactation curve and the 245  ± 28  kg, respectively. Suckling calf weight in- decreasing quality of the forages available. Or it creased over the grazing period and gained 1.39 ± could suggest that heavier cows produced more 0.04 kg/d, whereas cows lost 0.19 ± 0.04 kg/d as the milk and, therefore, calves from heavier cows con- season advanced, which was likely due to declining sumed less minerals at the feeders. It has been re- forage nutrient content combined with demands ported that suckling calves increase forage intake to of lactation. The variation in nutrient require- compensate for reduced milk intake (Boggs et  al., ments that come from changes in forage nutritive 1980). Therefore, calves in the current study could value and availability results in cows increasing and be responding to variation in cow milk production Table 3. Performance of grazing cow–calf pairs on native range utilizing an electronic feeder a b Calves Cows P-value Item High Low High Low SEM Age class Intake category Class × Category BW, kg Pasture turnout 92.3 89.9 607.9 597.2 10.8 <0.0001 0.549 0.709 June 5 114.7 115.3 588.9 581.7 10.9 <0.0001 0.766 0.720 July 3 147.8 149.2 585.0 577.9 11.3 <0.0001 0.800 0.707 July 31 182.8 182.8 587.6 577.7 11.1 <0.0001 0.660 0.656 Aug 28 217.5 215.1 581.8 565.9 10.7 <0.0001 0.393 0.529 Final 249.1 245.6 571.3 563.9 11.7 <0.0001 0.647 0.868 Gain , kg 134.4 130.3 −17.7 −17.8 4.02 <0.0001 0.602 0.626 ADG , kg/d 1.41 1.37 −0.19 −0.19 0.04 <0.0001 0.602 0.626 Calf divergent mineral intake classified calves as high (>50 g/d) or low (<50 g/d) mineral intake. Cow divergent mineral intake classified cows as high (>90 g/d) or low (<90 g/d) mineral intake. Pasture turnout weights are the mean value of consecutive day weights of cows and calves on May 15 and 16, 2017. June 5 weight is the start weight used for the 95-d monitoring period. Final BW are the mean value of consecutive day weights of cows and calves on September 25 and 26, 2017. Gain: the BW gained from start weight to final BW during the 95-d monitoring period. ADG: average daily gain is weight gained divided by the 95-d monitoring period. Translate basic science to industry innovation Individual cow and calf mineral intake by altering the consumption of available forage and and between different types of feedstuffs (Suttle, mineral supplementation. However, the milk intake 2010). However, pasture Se concentrations were of calves was not evaluated in this study. below detectable levels for the assay (0.10 mg/kg) and were thus deficient. Iron in pastures has been shown to have seasonal fluctuations with peaks in Forage Analysis spring and autumn (Suttle, 2010), where our cur- rent forage Fe concentrations were adequate over Forage nutrient content appeared to decrease the course of the grazing season. According to over the course of the mineral intake grazing Corah and Dargatz (1996), forage Fe is within ad- period (Table 5) as noted with decreasing CP equate levels at 50–200 mg/kg. Concentrations of and increasing values for NDF and ADF. A  de- Cu in forage were marginal to deficient (4–7 vs. crease in the forage nutritive value is typical in <4 mg/kg, respectively; Corah and Dargatz, 1996). the diets of grazing cattle during the advancing Furthermore, NASEM (2016) recommends con- season (Bedell, 1971; Schauer et  al., 2004; Cline centrations of Cu to be 10  mg/kg in beef cattle et  al., 2009). The nutrient availability of grazed diets. According to Corah and Dargatz (1996), forages fluctuates by environmental conditions, concentrations of Zn were deficient (<20  mg/kg) forage species, soil type, and stage of maturity over the course of the grazing period, whereas, (NASEM, 2016). Recommended allowance for according to Corah and Dargatz (1996), Mo, Co, Se, Fe, Cu, Zn, and Mn are 0.10, 50, 10, 30, and and Mn were adequate (<1, 0.1–0.25, >40 mg/kg, 40  mg/kg dietary DM, respectively (NASEM, respectively). Grings et  al. (1996) found that Mo 2016). Selenium in forage can range widely within Table 4. Correlations among performance and mineral feeding behavior of cows and calves while grazing native range a b c Cow duration Cow BW Cow intake Calf ADG Calf duration Calf intake Cow duration – 0.041 (P = 0.84) 0.923 (P < 0.01) −0.135 (P = 0.50) 0.306 (P = 0.13) 0.403 (P = 0.05) Cow BW – 0.048 (P = 0.81) 0.204 (P = 0.23) −0.631 (P < 0.01) −0.553 (P < 0.01) Cow intake – −0.134 (P = 0.51) 0.185 (P = 0.36) 0.279 (P = 0.19) Calf ADG – −0.166 (P = 0.42) −0.212 (P = 0.32) Calf duration – 0.948 (P < 0.01) Calf intake – Total amount of time (minutes) cows spent at the mineral feeder. Cow BW at the start of the 95-d monitoring period. Total amount of time (minutes) calves spent at the mineral feeder. Table 5. Forage analysis of pasture grazed by cow–calf pairs from May to September 2017 Grazing period Item May June July August September TDN 63.9 63.25 62.05 61.45 60.23 CP, % 9.08 8.30 6.47 5.82 6.67 Ash 10.27 9.42 9.31 9.79 10.09 NDF, % 58.98 60.88 62.48 62.04 65.22 ADF, % 31.65 32.46 33.97 34.75 36.27 Ca, % 0.36 0.37 0.40 0.40 0.44 P, % 0.19 0.16 0.14 0.12 0.14 S, % 0.1259 0.1285 0.1107 0.1160 0.1257 Fe, mg/kg 144.0 90.5 92.5 77.5 193.7 Cu, mg/kg 4.40 4.20 3.20 2.95 3.70 Zn, mg/kg 18.30 17.85 14.35 15.10 17.23 Mo, mg/kg 1.20 0.95 1.30 1.25 1.37 Mn, mg/kg 86.3 67.3 72.1 84.4 99.8 Clipped forage samples from 10 different locations reported herein are composite over all locations within the representative sampling dates. Values presented are mean values of the representative sampling dates within the given month: May (n = 1), June (n = 2), July (n = 2), August (n = 2), and September (n = 3). Total Digestible Nutrients = 88.9 – (0.79 × ADF%) (Lardy, 2018). Translate basic science to industry innovation McCarthy et al. content ranged from 1 to 2 mg/kg in forages from ranges in the low-intake cows, Cu status was near the Northern Great Plains, which our pastures the threshold for marginal status. fall within this similar range. Taken together, the analyzed mineral composition of the pastures re- CONCLUSIONS vealed that providing supplements containing Cu and Zn was warranted. The use of an electronic feeder in the pasture en- abled the measurement of individual ad libitum in- take of free-choice minerals by individual cows and Liver Mineral Concentrations calves. In this system, all cow–calf pairs had equal ad libitum access to native range forage and access to Cows with high mineral intake had greater minerals. Overall, calves spent more time at the feeder (P < 0.01) liver concentrations of Se, Cu, and Co compared to cows. Additionally, high-intake cows compared with low mineral intake cows, but liver and calves spent more time at the mineral feeder than concentrations of Fe, Zn, Mo, and Mn did not their low-intake counterparts. Furthermore, we noted differ (P ≥ 0.22; Table 6) among cows in respective greater concentrations of Se, Cu, and Co in livers of mineral intake categories. Selenium concentra- high-intake cows compared to low-intake cows. In tions in the liver for high cows were classified as conclusion, we were able to successfully monitor min- high adequate (>2.50  μg/g DM; Kincaid, 2000) eral intake and feeding behavior with the electronic and low mineral intake cows were classified as ad- feeder evaluated, and the divergence in mineral intake equate (1.25 to 2.50 μg/g DM; Kincaid, 2000). For observed with the feeder was corroborated by concen- liver concentrations of Cu, low cows would be just trations of minerals in the liver. under the threshold of 125 μg/g DM considered adequate by Kincaid (2000) but still considered LITERATURE CITED normal according to Radostits et  al. (>100  μg/g DM; Radostits et al. 2007). Cows in the high and AOAC. 1990. Official methods of analysis. 15th ed. Assoc. Off. Anal. Chem., Arlington, VA. low mineral intake categories both had liver Co Bedell, T. E. 1971. Nutritive value of forage and diets of sheep above the satisfactory threshold of 0.08 to 0.12 and cattle from Oregon subclover-grass mixtures. J. Range μg/g DM set forth by McNaught (1948), which Manage. 24:125–133. doi:10.2307/3896521 high and low cows were above satisfactory lev- Boggs,  D.  L., E.  F.  Smith, R.  R.  Schalles, B.  E.  Brent, els. According to Kincaid (2000), liver mineral L.  R.  Corah, and R.  J.  Pruitt. 1980. Effects of milk and concentrations for Fe, Zn, Mo, and Mn are con- forage intake on calf performance. J. Anim. Sci. 51:550– 553. doi:10.2527/jas1980.513550x. sidered adequate for high and low groups. Overall, Bowman, J. G., and B. F. Sowell. 1997. Delivery method and cows in the high mineral intake groups had greater supplement consumption by grazing ruminants: a review. concentrations of Se, Cu, and Co, indicating more J. Anim. Sci. 75:543–550. doi:10.2527/1997.752543x. available bodily stores of minerals for their own Cline,  H.  J., B.  W.  Neville, G.  P.  Lardy, and J.  S.  Caton. physiological and metabolic processes and for 2009. Influence of advancing season on dietary com- position, intake, site of digestion, and microbial effi- those of their gestating offspring. In addition, ciency in beef steers grazing a native range in western though most minerals evaluated were in adequate North Dakota. J. Anim. Sci. 87:375–383. doi:10.2527/ jas.2007-0833. Cockwill, C. L., T. A. McAllister, M. E. Olson, D. N. Milligan, Table 6. Liver mineral concentrations of cows with B.  J.  Ralston, C.  Huisma, and R.  K.  Hand. 2000. divergent mineral intake from an electronic feeder Individual intake of mineral and molasses supplements a by cows, heifers and calves. Can. J. Anim. Sci. 80:681–690. Intake category doi:10.4141/A99-120. Item, μg/g High Low SE P-value Corah,  L.  R., and D.  Dargatz. 1996. Forage analyses from n 9 9 cow/calf herds in 18 states. Report: beef cow/calf health a b Se 2.92 2.41 0.10 0.003 and productivity audit. Available from https://www.aphis. Fe 202.3 220.0 21.9 0.576 usda.gov/animal_health/nahms/beefcowcalf/downloads/ a b Cu 247.0 115.6 21.6 0.0005 chapa/CHAPA_dr_ForageAnal.pdf (accessed October 1, Zn 110.7 118.7 16.5 0.737 2018). Engle, T. E., and J. W. Spears. 2000. Effects of dietary copper Mo 3.98 3.75 0.29 0.595 concentration and source on performance and copper Mn 9.74 8.84 0.50 0.217 status of growing and finishing steers. J. Anim. Sci. a b Co 0.51 0.27 0.05 0.002 78:2446–2451. doi:10.2527/2000.7892446x. ab Greene,  L.  W. 2000. Designing mineral supplementation of Means within row lacking common superscript differ (P < 0.05). forage programs for beef cattle. J. Anim. Sci. 77:1–9. doi: Cow divergent mineral intake classified cows as high (>90 g/d) or 10.2527/jas2000.00218812007700ES0013x. low (< 90 g/d) mineral intake. Translate basic science to industry innovation Individual cow and calf mineral intake Grings,  E.  E., M.  R.  Haferkamp, R.  K.  Heitschmidt, and Pehrson, B., K. Ortman, N. Madjid, and U. Trafikowska. 1999. M.  G.  Karl. 1996. Mineral dynamics in forages of the The influence of dietary selenium as selenium yeast or so- Northern Great Plains. J. Range Manag. 49:234–240. doi: dium selenite on the concentration of selenium in the milk 10.2307/4002884. of Suckler cows and on the selenium status of their calves. Islas,  A., T.  C.  Gilbery, R.  S.  Goulart, C.  R.  Dahlen, J. Anim. Sci. 77:3371–3376. doi:10.2527/1999.77123371x. M. L. Bauer, and K. C. Swanson. 2014. Influence of sup- Radostits,  O.  M., C.  C.  Gay, K.  W.  Hinchcliff, and plementation with corn dried distillers grains plus solubles P.  D.  Constable. 2007. Veterinary medicine: a textbook to growing calves fed medium-quality hay on growth per- of the diseases of cattle, horses, sheep, pigs, and goats. formance and feeding behavior. J. Anim. Sci. 92:705–711. Philadelphia (PA): Saunders Elsevier. doi:10.2527/jas.2013-7067. Reuter, R. R., C. A. Moffet, G. W. Horn, S. Zimmerman, and Kincaid,  R.  L. 2000. Assessment of trace mineral status of M. Billars. 2017. Technical note: daily variation in intake ruminants: a review. J. Anim. Sci. 77(Suppl. 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Comparison of techniques for estimation of forage S1080-7446(15)31723-X. dry matter intake by grazing beef cattle. Can. J. Anim. Sci. NASEM. 2016. Nutrient requirements of beef cattle. 8th rev. 88:693–701. doi:10.4141/CJAS08041. ed. National Academies Press, Washington, DC. Van  Soest,  P.  J., J.  B.  Robertson, and B.  A.  Lewis. 1991. NDAWN. 2017. North Dakota Agricultural Weather Network. Methods for dietary fiber, neutral detergent fiber, and Available from https://ndawn.ndsu.nodak.edu/ (accessed nonstarch polysaccharides in relation to animal nu- August 15, 2018). trition. J. Dairy Sci. 74:3583–3597. doi:10.3168/jds. Patterson,  J.  D., W.  R.  Burris, J.  A.  Boling, and J.  C.  Matthews. S0022-0302(91)78551-2. 2013. Individual intake of free-choice mineral mix by grazing Wolfger, B., E. Timsit, E. A. Pajor, N. Cook, H. W. Barkema, beef cows may be less than typical formulation assumptions and K.  Orsel. 2015. Technical note: accuracy of an ear and form of selenium in mineral mix affects blood Se concen- tag-attached accelerometer to monitor rumination and trations of cows and their suckling calves. Biol. Trace Elem. feeding behavior in feedlot cattle. J. Anim. Sci. 93:3164– Res. 155:38–48. doi:10.1007/s12011-013-9768-7. 3168. doi:10.2527/jas.2014-8802. Translate basic science to industry innovation http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Translational Animal Science Oxford University Press

Utilizing an electronic feeder to measure individual mineral intake, feeding behavior, and growth performance of cow–calf pairs grazing native range1

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© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science.
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Abstract

Utilizing an electronic feeder to measure individual mineral intake, feeding behavior, and growth performance of cow–calf pairs grazing native range †,2 ‡ ‡ †,3, Kacie L. McCarthy, Michael Undi, Stephanie Becker, and Carl R. Dahlen Department of Animal Sciences, North Dakota State University, Fargo, ND 58102, USA; and Central Grasslands Research Extension Center, North Dakota State University, Streeter, ND 58483, USA ABSTRACT:  Crossbred Angus cow–calf pairs (>90  g/d; average 125.4  g/d) and low (<90  g/d; (n = 28 pairs) at the Central Grasslands Research average 33.5  g/d) mineral intake was performed Extension Center (Streeter, ND) were used to using the GLM procedure. High-intake calves evaluate an electronic feeder to monitor indi- (>50  g/d; average 72.2  g/d) consumed greater vidual mineral intake and feeding behavior and (P < 0.001) amounts of minerals than low-intake their relationship with growth performance and calves (<50  g/d; average 22.2  g/d) intake calves. liver mineral concentrations. Cows and calves Cows and calves attended the mineral feeder a were fitted with radio frequency identification similar (P = 0.71) proportion of the days during ear tags that allowed access to an electronic the experiment (overall mean of 20%, or once feeder (SmartFeed system; C-Lock Inc., Rapid every 5 d). On days calves visited the feeder, they City, SD) and were provided ad libitum minerals consumed less (P  <  0.01) minerals than cows (Purina Wind and Rain Storm, Land O’Lakes, (222 ± 27 vs. 356 ± 26 g/d, respectively). Over the Inc., Arden Hills, MN). Mineral intake, number grazing period, calves gained 1.17  ± 0.02  kg/d, of visits, and duration at the feeder were re- whereas cows lost 0.35 ± 0.02 kg/d. Calf mineral corded over a 95-d monitoring period while intake was correlated with cow duration at the pairs were grazing native range. Liver biopsies mineral feeder (r  =  0.403, P = 0.05). Cows with were collected from a subset of cows on the high mineral intake had greater (P < 0.01) con- final day of monitoring and analyzed for min- centrations of Se (2.92 vs. 2.41 ug/g), Cu (247 vs. eral concentrations. Data were analyzed with the 116 ug/g), and Co (0.51 vs. 0.27 ug/g) compared GLM procedure in SAS for mineral intake and with low mineral intake cows, but liver concen- feeding behavior with age class (cows vs. calves), trations of Fe, Zn, Mo, and Mn did not differ intake category (high vs. low), and the inter- (P ≥ 0.22). We were able to successfully monitor action between class and category in the model. individual mineral intake and feeding behavior Correlations were calculated among cow feeding with the electronic feeder evaluated, and the di- behavior and calf intake and growth performance vergence in mineral intake observed with the with the CORR procedure, and a comparison of feeder was corroborated by concentrations of liver mineral concentrations among cows of high minerals in the liver. Key words: cow–calf, grazing, intake, mineral Authors would like to thank the North Dakota Agricul- the NDSU Nutrition Lab for their assistance with sample tural Experiment Station Precision Agriculture Fund and analysis. the North Dakota State Board of Agricultural Research and Present address: Department of Animal Science, Education Graduate Assistantship programs for their sup- University of Nebraska, Lincoln, NE 68583, USA port for this effort. Appreciation is also expressed to person- Corresponding author: carl.dahlen@ndsu.edu nel at the Central Grasslands Research and Extension Center Received October 26, 2020. for assistance with animal handling and forage collection and Accepted January 15, 2021. 1 McCarthy et al. © The Author(s) 2021. 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- NonCommercial 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. 2021.5:1-9 doi: 10.1093/tas/txab007 performance and concentrations of minerals in the INTRODUCTION liver. Mineral requirements of grazing cattle are not always satisfied by forages (McDowell, 1996); thus, MATERIALS AND METHODS mineral supplementation is often necessary to op- All animal procedures were approved by the timize animal health and performance (NASEM, Institutional Animal Care and Use Committee at 2016). An issue with providing mineral supple- North Dakota State University (A17064). ments to cattle, however, is the high degree of in- take variability associated with free-choice mineral supplements (Cockwill et al., 2000; Greene, 2000). Study Area Mineral intake variability is influenced by season, Research was conducted at the Central individual animal requirements, animal preference, Grasslands Research Extension Center, located availability of fresh minerals, mineral palatability, near Streeter, ND, from May 22, 2017 to September physical form of minerals, salt content of water, 27, 2017. This area is characterized by a contin- mineral delivery method, soil fertility and forage ental climate with warm summers and cold winters type, forage availability, animal social interactions, with a majority (72%) of precipitation occurring and likely other unknown factors (Bowman and between May and September (Limb et  al., 2018). Sowell, 1997; McDowell, 2003). August is the warmest month with a mean tempera- Providing free-choice mineral supplements to ture of 18.6  °C and January is the coldest month pasture-based cattle does not allow the measure- with an average low temperature of −15.3 °C (Fig. ment of individual animal mineral intake; as a re- 1; NDAWN, 2017). sult, mineral intake is measured on a group basis. The pasture was 62 ha with a stocking rate The measurement of individual animals’ mineral of 2.1 animal unit months/ha. The vegetation is supplement intake allows specific animal responses classified as mixed-grass prairie dominated by to be evaluated. Individual animal intake of free- western wheatgrass (Pascopyrum smithii [Rydb.] À. choice minerals is often variable due to the small amounts consumed (Tait and Fisher, 1996). The use of electronic monitoring systems in the beef in- dustry has been limited to systems primarily used in research settings to examine the effects on feed in- take in relation to cattle growth performance (Islas et  al., 2014), daily intake of salt-limited supple- ments (Reuter et al., 2017), health status (Wolfger et al., 2015), or animal movement in extensive pas- ture settings (Schauer et al., 2005). These technolo- gies could be adapted easily for use in beef cattle production systems to monitor activity, feeding, or drinking behavior or as tools for monitoring inven- tories in intensive or extensive production systems. Moreover, these technologies could be applied to target specific cow or calf supplementation strat- egies in pasture settings. Therefore, our objective Figure 1. Temperature and precipitation data from April to was to evaluate an electronic feeder to monitor October 2017 compared with 25-yr average. Data from North Dakota individual cow and calf mineral intake and feed- Agricultural Weather Network Station located in Streeter, ND ing behavior and their relationship with growth (NDAWN, 2017). Translate basic science to industry innovation Individual cow and calf mineral intake Löve), green needlegrass (Nassella viridula [Trin.] Table 1. Composition of mineral supplement con- Barkworth), and blue grama (Bouteloua graciles sumed by cow–calf pairs grazing native range; com- [Willd. ex Kunth] Lag. ex Griffiths). Other im- pany guaranteed analysis portant species present that are important drivers Item Min Max in biodiversity changes in the region include sedges Minerals (Carex spp.), prairie junegrass (Koeleria macrantha Ca, % 13.5 16.2 [Ledeb.] Schult.), sages (Artemisia spp.), and gold- P, % 7.5 – enrods (Solidago spp.), Kentucky bluegrass (Poa NaCl, % 18.0 21.6 pratensis L.) a nonnative grass, and western snow- Mg, % 1.0 – berry (Symphoricarpos occidentalis Hook.) a native K, % 1.0 – Mn, mg/kg 3,600 – shrub (Limb et al., 2018). Co, mg/kg 12 – Cu, mg/kg 1,200 – Electronic Feeder Device I, mg/kg 60 – Se, mg/kg 27 – The SmartFeed system (C-Lock, Inc., Rapid Zn, mg/kg 3,600 – City, SD) was used to deliver mineral supplement Vitamins, IU/kg and measure intake. The system features a stain- Vitamin A 661,500 – less-steel feed bin suspended on two load cells, a Vitamin D 66,150 – radio frequency identification (RFID) tag reader Vitamin E 661.5 – and antenna, an adjustable framework to allow ac- Purina Wind and Rain Storm Mineral (Land O’Lakes, Inc., Arden cess to one animal at a time, and a data acquisition Hills, MN). Ingredients: dicalcium phosphate, monocalcium phos- system that records RFID tags and feed bin weights phate, calcium carbonate, salt, processed grain byproducts, vegetable (Reuter et al., 2017). The electronic feeder was fas- fat, plant protein products, potassium chloride, magnesium oxide, natural and artificial flavors, calcium lignin sulfonate, ethoxyquin (a tened securely to the fence line to allow animal ac- preservative), manganese sulfate, zinc sulfate, basic copper chloride, cess to the feeder and restrict access to electrical ethylenediamine dihydroiodide, cobalt carbonate, vitamin A  supple- components and solar power source. The mineral ment (proprietary), vitamin E supplement (proprietary), and vitamin feeder was located down the fence line in a corner D3 supplement (proprietary). of the pasture 0.2 km away from the water source. started from initial pasture turn out (May 22, The feeder was covered with a plywood shell to pro- 2017) to June 22, 2017. Mineral intake, number of tect the feed bin and equipment from wind and rain. visits, time of visits, and duration at the feeder were Mineral disappearance in the feeder was monitored recorded continuously during a 95-d monitoring visually and through the online portal where intake period while pairs were grazing native range from and monitoring of the device were done remotely. June 23, 2017 to September 27, 2017. Daily mineral intake was calculated as the sum of individual feed- Animal Measurements ing events in each 24-h period and overall mineral intake was the sum of all feeding events during the Twenty-eight crossbred Angus based prim- 95-d monitoring period. The mean value for overall iparous cows [initial body weight (BW)  =  586  ± intake was used as an inflection point to categorize 52 kg] and their suckling calves (initial BW 113 ± cattle into mineral intake groups. Cows and calves 19  kg; 66  ± 8 d of age) were used to evaluate an were categorized into one of two mineral intake electronic feeder to monitor mineral intake and classifications: high (>90 or >50  g/d for cows and feeding behavior and their relationship with growth calves, respectively) and low (<90 or <50  g/d for performance and concentrations of minerals in the cows and calves, respectively) mineral intake during liver. The mean value of consecutive day weights of the 95-d monitoring period. cows and calves were used as initial and final BWs, with single-day BWs collected at 28-d intervals. Cows and calves were fitted with RFID ear tags Liver Sample Collection and Analysis that allowed access to the electronic feeder, which contained free-choice loose minerals (Purina Wind Samples of liver were collected on day 95 and Rain Storm, Land O’Lakes, Inc., Arden Hills, via biopsy from a subset of cows (n  =  18) with MN; Table 1). the greatest and least attendance at the mineral The SmartFeed unit was set in training mode feeder throughout the grazing period. Cows were (lowest locked setting to allow for ad libitum ac- restrained in a squeeze chute, and the hair be- cess to the feeder) and training cattle to the feeders tween the 10th and 12th ribs was clipped with Translate basic science to industry innovation McCarthy et al. size 40 blades (Oster; Sunbeam Products Inc., CP calculation. Neutral detergent fiber (NDF) and Boca Raton, FL). Liver biopsy samples (approxi- acid detergent fiber (ADF) concentrations were de- mately 20  mg) were collected using the method termined by the modified method of Van Soest et al. of Engle and Spears (2000) with the modifica- (1991) using a fiber analyzer (Ankom Technology tions that all heifers were given 3  mL Lidocaine Corp., Fairport, NY). Samples were also analyzed Injectable-2% (MWI, Boise, ID) with 1.5  mL for Cu, Zn, Co, Mo, Fe, S, and Se using inductively subcutaneously and 1.5  mL into the intercostal coupled plasma optical emission spectroscopy by muscles at the target biopsy site. An imaginary the Veterinary Diagnostic Laboratory at Michigan line is drawn from the tuber coxae (hook) to the State University. elbow. At the intersection with a line drawn hori- zontally from the greater trochanter, a stab inci- Statistical Analysis sion was then made between the 10th intercostal Data were analyzed using the GLM procedure space. A  core sample of the liver was taken via of SAS (SAS 9.4; SAS Inst. Inc., Cary, NC) with the Tru-Cut biopsy trochar (14 g; Merit Medical, mineral intake and feeding behavior compared South Jordan, UT). The liver sample was blotted among cows and calves. Mineral intake, feeding dry on ashless filter paper (Whatman 541 behavior, and performance were analyzed by age Hardened Ashless Filter Papers, GE Healthcare class (cows vs. calves), intake category (high vs. Bio-Sciences, Pittsburg, PA) and then stored in low), and the interaction between class and cat- tubes designed for trace mineral analysis (potas- egory. Correlations were generated among cows sium Ethylenediaminetetraacetic acid; Becton and calves with the variables cow duration at the Dickinson Co., Franklin Lakes, NJ) and stored feeder, intake, and BW and calf average daily gain, at −20  °C until further analysis. After obtaining intake, and duration at the feeder using the CORR liver biopsies, a staple (Disposable Skin Staple 35 procedure of SAS. Comparisons of liver mineral Wide; Amerisource Bergen, Chesterbrook, PA) concentrations among cows of high (>90 g/d) and and topical antibiotic (Aluspray; Neogen Animal low (<90  g/d) mineral intake were analyzed with Safety, Lexington, KY) was applied to the sur- PROC GLM. For all analyses, significance was set gical site and an injectable Nonsteroidal Anti- at P ≤ 0.05. inflammatory Drug (Banamine; Merck Animal Health, Madison, NJ) was given intravenously at RESULTS AND DISCUSSION 1.1 mg/kg of BW. Liver samples were sent to the Veterinary Diagnostic Laboratory at Michigan State University and were evaluated for concen- Mineral Intake and Feeding Behavior trations of minerals using inductively coupled Over the duration of the 95-d grazing period, plasma mass spectrometry. cows consumed more (P  <  0.001; Table 2) min- erals than calves. An age class × mineral intake category interaction (P  =  0.005) was detected Forage Collection and Analysis for intake over the 95-d monitoring period, with Forage samples were obtained every 2 wk from high-intake cows having greater mineral con- 10 different locations in the pasture in a diagonal sumption (125.4  g/d; P  <  0.001) compared with line across the pasture. The forage samples were high-intake calves (72.2  g/d), which were greater hand clipped to a height of 3.75 cm above ground (P < 0.001) than low-intake cows and calves (33.5 (Undi et al., 2008). Forage samples were dried in a vs. 22.2 g/d, respectively). Generally, cattle mineral forced-air oven at 60 °C for at least 48 h and then formulations are designed to fall within the tar- ground to pass through a 2-mm screen using a geted intake of between 56 and 114 g/d per animal Wiley mill (Arthur H. Thomas, Philadelphia, PA). for free-choice mineral supplementation (Greene, Clipped forage samples for each location reported 2000). Variability in feeder attendance and daily herein are composite over all locations within the mineral intake by individual cattle utilizing other representative sampling date. Forage samples were electronic feeders have been reported by multiple analyzed at the North Dakota State University research groups (Cockwill et  al., 2000; Manzano Nutrition Laboratory for dry matter (DM), crude et  al, 2012; Patterson et  al., 2013). Furthermore, protein (CP), ash, N (Kjehldahl method), Ca, P, Patterson et  al. (2013) evaluated cows and their and ether extract (EE) by standard procedures calves using a Calan gate feeder system and pro- (AOAC, 1990). Multiplying N by 6.25 determined vided three different supplemental sources of Se Translate basic science to industry innovation Individual cow and calf mineral intake Table 2. Mineral intake and feeding behavior of grazing cow–calf pairs on native range utilizing an elec- tronic feeder a b Calves Cows P-value Item High Low High Low SEM Age class Intake category Class × Category c b c a c 95 d intake , g/d 72.2 22.2 125.4 33.5 5.7 <0.001 <0.001 0.005 Days eating, % 27.5 14.5 27.5 14.5 1.4 0.83 <0.001 0.64 d b c a b Intake , g/d 300.1 161.2 461.8 242.5 28.1 <0.001 <0.001 0.005 Time , min 147.3 57.2 118.4 39.4 9.3 0.02 <0.001 0.56 Eating rate, g/min 49.4 39.2 106.6 74.8 7.3 <0.001 <0.006 0.14 abc Means within row lacking common superscript differ (P < 0.05). Calf divergent mineral intake classified calves as high (>50 g/d) or low (<50 g/d) mineral intake. Cow divergent mineral intake classified cows as high (>90 g/d) or low (<90 g/d) mineral intake. Represents average daily intake over the course of the 95-d monitoring period. Represents daily intake on the days cows and calves attended the electronic feeder. Time represents the total time in minutes spent at the feeder over the course of the 95-d monitoring period. during a year-long production regimen and also re- time at the feeder resulted in a slower overall rate ported variability with intakes ranging from 27.9 of mineral consumption for calves compared with to 97.3  g/d with a mean mineral consumption of cows (P  <  0.0001), and high-intake animals ate 54  g/d. However, calf intake was not evaluated in faster (P < 0.006) than low-intake animals. It is im- Patterson et al. (2013). Compared to utilizing elec- portant to note that both classes of cattle attended tronic feeders, Pehrson et al. (1999) provided min- the mineral feeders for a similar (P = 0.71) propor- eral supplement in a wooden box to grazing cows for tion of days during the experiment (overall mean an 80-d period and calculated the mean daily sup- of only 20% or once every 5  days). Interestingly plement consumption by dividing the total amount though, mean intake values for cows and calves of feed by the number of animals consuming it, over the course of the experiment did not meet with the assumption that calves did not consume manufacturers’ feeding recommendation (113.4  g) any significant amount. Thus, Pehrson et al. (1999) for the minerals used because the cattle did not estimated that the daily consumption for Se yeast visit the feeders every day but the mineral intake of mineral supplement was 110  g/cow, whereas cows both cows and calves exceeded the manufacturers supplemented with selenite consumed 107  g/cow. feeding recommendation on days they did visit the Our group was able to use the SmartFeed system feeders. to evaluate the mineral intake of cow–calf pairs on Mineral intake on the days cows and calves pasture and record individual intakes of calves that visited the mineral feeders was impacted by an age the aforementioned groups were unable to evaluate. class × intake category interactions (P  =  0.005), The observation of high-intake calves consuming with high-intake cows consuming more (P < 0.001) more minerals than low-intake cows reveals the im- minerals (461.8  g/d) than low-intake cows portance of considering calf intake when making (242.5  g/d) and high-intake calves (300.1  g/d), decisions about the amount of supplement to be which consumed more (P < 0.001) than low-intake offered or interpreting mineral disappearance in calves (161.2  g/d). Cockwill et  al. (2000) reported pastures where cow–calf pairs are grazing. high variability of mineral intake over a 6-d grazing No class × category interactions (P > 0.14) period with individual intakes among cows and were present in the proportion of days cattle con- calves ranging from 0 to 974 and 0 to 181 g/d, re- sumed mineral, time spent at the feeder, or eating spectively. Unfortunately, little field data exist for rate (Table 2). Furthermore, no differences were ob- individual free-choice mineral intake by cows and served for age class for the proportion of days at- calves managed under forage-based cow–calf regi- tending the feeder (P = 0.83); however, high-intake mens (Patterson et  al., 2013). The current experi- cattle spent a greater proportion of days consuming ment offers a glimpse of mineral intake variability minerals compared to low-intake cattle (P < 0.001). over a 3-month period in cows and calves grazing Overall, calves spent more time at the feeder com- the native range. pared to cows (P  <  0.001), and high-intake cows With the proportion of days during the experi- and calves spent more time at the mineral feeder ment that cattle were consuming minerals, the lo- than their low-intake counterparts (P = 0.02). The cation of the mineral feeder and grazing behavior reduced intake of calves combined with a longer may explain the variation in intake over the grazing Translate basic science to industry innovation McCarthy et al. period. It is probable that such distances from the decreasing in BW and body condition in a cyclic water source could also alter patterns of electronic pattern throughout the production year (NASEM, feeder attendance. Likewise, Smith et  al. (2016) 2016). Additionally, primiparous cows require add- reported that individual steers visited a mineral itional nutrient requirements for their own growth, feeder an average of 44.3% of the days monitored meeting nutrient requirements for lactation to sup- (90-d monitoring period) when the mineral feeder port an existing offspring, and overall maintenance was in immediate proximity to the water source. (Short et  al., 1990; Meek et  al., 1999; NASEM, In the current experiment, we did not implement 2016), which makes it hard to gain weight. a training period before pasture turnout; thus, the The amount of time cows spent at the mineral novelty of the feeder could have contributed to the feeder was positively correlated with cow mineral in- neophobic behavior of new feeding devices or feeds take (r = 0.923; P < 0.01; Table 4). Additionally, the (Bowman and Sowell, 1997). However, the training amount of time calves spent at the feeder was posi- period utilized in the experiment should have been tively correlated with calf mineral intake (r = 0.948; sufficient to overcome the neophobic behavior. P  <  0.01). The time cows spent at the feeder was Probably, the inability to move the feeder away also positively correlated with calf mineral intake from the corner of the pasture and closer to the (r  =  0.403; P  =  0.05). Similar findings have been water or increase cattle traffic influenced the pro- reported with inexperienced sheep increasing sup- portion of days the cattle attended the feeder. plement intake in the presence of more experienced sheep (Bowman and Sowell, 1997). Furthermore, cow starting BW was negatively correlated with the Cow and Calf Performance duration the calf spent at the feeder and calf intake There were no class by intake category inter- (r  =  −0.631 and −0.553, respectively; P  <  0.01). actions (P ≥ 0.53; Table 3) for cow and calf BWs This could suggest that as the grazing season pro- over the course of the monitoring period (Table 3). gressed, the cow’s milk production was declining Final BW for cows and calves were 568 ± 53 kg and because of the normal lactation curve and the 245  ± 28  kg, respectively. Suckling calf weight in- decreasing quality of the forages available. Or it creased over the grazing period and gained 1.39 ± could suggest that heavier cows produced more 0.04 kg/d, whereas cows lost 0.19 ± 0.04 kg/d as the milk and, therefore, calves from heavier cows con- season advanced, which was likely due to declining sumed less minerals at the feeders. It has been re- forage nutrient content combined with demands ported that suckling calves increase forage intake to of lactation. The variation in nutrient require- compensate for reduced milk intake (Boggs et  al., ments that come from changes in forage nutritive 1980). Therefore, calves in the current study could value and availability results in cows increasing and be responding to variation in cow milk production Table 3. Performance of grazing cow–calf pairs on native range utilizing an electronic feeder a b Calves Cows P-value Item High Low High Low SEM Age class Intake category Class × Category BW, kg Pasture turnout 92.3 89.9 607.9 597.2 10.8 <0.0001 0.549 0.709 June 5 114.7 115.3 588.9 581.7 10.9 <0.0001 0.766 0.720 July 3 147.8 149.2 585.0 577.9 11.3 <0.0001 0.800 0.707 July 31 182.8 182.8 587.6 577.7 11.1 <0.0001 0.660 0.656 Aug 28 217.5 215.1 581.8 565.9 10.7 <0.0001 0.393 0.529 Final 249.1 245.6 571.3 563.9 11.7 <0.0001 0.647 0.868 Gain , kg 134.4 130.3 −17.7 −17.8 4.02 <0.0001 0.602 0.626 ADG , kg/d 1.41 1.37 −0.19 −0.19 0.04 <0.0001 0.602 0.626 Calf divergent mineral intake classified calves as high (>50 g/d) or low (<50 g/d) mineral intake. Cow divergent mineral intake classified cows as high (>90 g/d) or low (<90 g/d) mineral intake. Pasture turnout weights are the mean value of consecutive day weights of cows and calves on May 15 and 16, 2017. June 5 weight is the start weight used for the 95-d monitoring period. Final BW are the mean value of consecutive day weights of cows and calves on September 25 and 26, 2017. Gain: the BW gained from start weight to final BW during the 95-d monitoring period. ADG: average daily gain is weight gained divided by the 95-d monitoring period. Translate basic science to industry innovation Individual cow and calf mineral intake by altering the consumption of available forage and and between different types of feedstuffs (Suttle, mineral supplementation. However, the milk intake 2010). However, pasture Se concentrations were of calves was not evaluated in this study. below detectable levels for the assay (0.10 mg/kg) and were thus deficient. Iron in pastures has been shown to have seasonal fluctuations with peaks in Forage Analysis spring and autumn (Suttle, 2010), where our cur- rent forage Fe concentrations were adequate over Forage nutrient content appeared to decrease the course of the grazing season. According to over the course of the mineral intake grazing Corah and Dargatz (1996), forage Fe is within ad- period (Table 5) as noted with decreasing CP equate levels at 50–200 mg/kg. Concentrations of and increasing values for NDF and ADF. A  de- Cu in forage were marginal to deficient (4–7 vs. crease in the forage nutritive value is typical in <4 mg/kg, respectively; Corah and Dargatz, 1996). the diets of grazing cattle during the advancing Furthermore, NASEM (2016) recommends con- season (Bedell, 1971; Schauer et  al., 2004; Cline centrations of Cu to be 10  mg/kg in beef cattle et  al., 2009). The nutrient availability of grazed diets. According to Corah and Dargatz (1996), forages fluctuates by environmental conditions, concentrations of Zn were deficient (<20  mg/kg) forage species, soil type, and stage of maturity over the course of the grazing period, whereas, (NASEM, 2016). Recommended allowance for according to Corah and Dargatz (1996), Mo, Co, Se, Fe, Cu, Zn, and Mn are 0.10, 50, 10, 30, and and Mn were adequate (<1, 0.1–0.25, >40 mg/kg, 40  mg/kg dietary DM, respectively (NASEM, respectively). Grings et  al. (1996) found that Mo 2016). Selenium in forage can range widely within Table 4. Correlations among performance and mineral feeding behavior of cows and calves while grazing native range a b c Cow duration Cow BW Cow intake Calf ADG Calf duration Calf intake Cow duration – 0.041 (P = 0.84) 0.923 (P < 0.01) −0.135 (P = 0.50) 0.306 (P = 0.13) 0.403 (P = 0.05) Cow BW – 0.048 (P = 0.81) 0.204 (P = 0.23) −0.631 (P < 0.01) −0.553 (P < 0.01) Cow intake – −0.134 (P = 0.51) 0.185 (P = 0.36) 0.279 (P = 0.19) Calf ADG – −0.166 (P = 0.42) −0.212 (P = 0.32) Calf duration – 0.948 (P < 0.01) Calf intake – Total amount of time (minutes) cows spent at the mineral feeder. Cow BW at the start of the 95-d monitoring period. Total amount of time (minutes) calves spent at the mineral feeder. Table 5. Forage analysis of pasture grazed by cow–calf pairs from May to September 2017 Grazing period Item May June July August September TDN 63.9 63.25 62.05 61.45 60.23 CP, % 9.08 8.30 6.47 5.82 6.67 Ash 10.27 9.42 9.31 9.79 10.09 NDF, % 58.98 60.88 62.48 62.04 65.22 ADF, % 31.65 32.46 33.97 34.75 36.27 Ca, % 0.36 0.37 0.40 0.40 0.44 P, % 0.19 0.16 0.14 0.12 0.14 S, % 0.1259 0.1285 0.1107 0.1160 0.1257 Fe, mg/kg 144.0 90.5 92.5 77.5 193.7 Cu, mg/kg 4.40 4.20 3.20 2.95 3.70 Zn, mg/kg 18.30 17.85 14.35 15.10 17.23 Mo, mg/kg 1.20 0.95 1.30 1.25 1.37 Mn, mg/kg 86.3 67.3 72.1 84.4 99.8 Clipped forage samples from 10 different locations reported herein are composite over all locations within the representative sampling dates. Values presented are mean values of the representative sampling dates within the given month: May (n = 1), June (n = 2), July (n = 2), August (n = 2), and September (n = 3). Total Digestible Nutrients = 88.9 – (0.79 × ADF%) (Lardy, 2018). Translate basic science to industry innovation McCarthy et al. content ranged from 1 to 2 mg/kg in forages from ranges in the low-intake cows, Cu status was near the Northern Great Plains, which our pastures the threshold for marginal status. fall within this similar range. Taken together, the analyzed mineral composition of the pastures re- CONCLUSIONS vealed that providing supplements containing Cu and Zn was warranted. The use of an electronic feeder in the pasture en- abled the measurement of individual ad libitum in- take of free-choice minerals by individual cows and Liver Mineral Concentrations calves. In this system, all cow–calf pairs had equal ad libitum access to native range forage and access to Cows with high mineral intake had greater minerals. Overall, calves spent more time at the feeder (P < 0.01) liver concentrations of Se, Cu, and Co compared to cows. Additionally, high-intake cows compared with low mineral intake cows, but liver and calves spent more time at the mineral feeder than concentrations of Fe, Zn, Mo, and Mn did not their low-intake counterparts. Furthermore, we noted differ (P ≥ 0.22; Table 6) among cows in respective greater concentrations of Se, Cu, and Co in livers of mineral intake categories. Selenium concentra- high-intake cows compared to low-intake cows. In tions in the liver for high cows were classified as conclusion, we were able to successfully monitor min- high adequate (>2.50  μg/g DM; Kincaid, 2000) eral intake and feeding behavior with the electronic and low mineral intake cows were classified as ad- feeder evaluated, and the divergence in mineral intake equate (1.25 to 2.50 μg/g DM; Kincaid, 2000). For observed with the feeder was corroborated by concen- liver concentrations of Cu, low cows would be just trations of minerals in the liver. under the threshold of 125 μg/g DM considered adequate by Kincaid (2000) but still considered LITERATURE CITED normal according to Radostits et  al. (>100  μg/g DM; Radostits et al. 2007). Cows in the high and AOAC. 1990. Official methods of analysis. 15th ed. Assoc. Off. Anal. Chem., Arlington, VA. low mineral intake categories both had liver Co Bedell, T. E. 1971. Nutritive value of forage and diets of sheep above the satisfactory threshold of 0.08 to 0.12 and cattle from Oregon subclover-grass mixtures. J. Range μg/g DM set forth by McNaught (1948), which Manage. 24:125–133. doi:10.2307/3896521 high and low cows were above satisfactory lev- Boggs,  D.  L., E.  F.  Smith, R.  R.  Schalles, B.  E.  Brent, els. According to Kincaid (2000), liver mineral L.  R.  Corah, and R.  J.  Pruitt. 1980. 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Technical note: accuracy of an ear and form of selenium in mineral mix affects blood Se concen- tag-attached accelerometer to monitor rumination and trations of cows and their suckling calves. Biol. Trace Elem. feeding behavior in feedlot cattle. J. Anim. Sci. 93:3164– Res. 155:38–48. doi:10.1007/s12011-013-9768-7. 3168. doi:10.2527/jas.2014-8802. Translate basic science to industry innovation

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Translational Animal ScienceOxford University Press

Published: Jan 21, 2021

Keywords: cow; calf; grazing; intake; mineral

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