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Effects of added fat on growth performance of finishing pigs sorted by initial weight

Effects of added fat on growth performance of finishing pigs sorted by initial weight Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 Effects of added fat on growth performance of finishing pigs sorted by initial weight ,‡ †, ,2 Chad W. Hastad,* Mike D. Tokach,* Steve S. Dritz, Robert D. Goodband,* ,$ Joel M. DeRouchey,* and Fangzhou Wu* *Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS 66506-0210; Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State ‡ $ University, Manhattan, KS 66506-0210; Present address: New Fashion Pork, Jackson, MN.; and Present address: Pipestone System, Pipestone, MN. ABSTRACT: Two studies were conducted to categories. Overall in experiment 1, adding 6% determine whether dietary fat fed to pigs of dif- dietary fat increased average daily gain (ADG) ferent weight categories differentially influences of LIGHT pigs, but not HEAVY pigs (HEAVY growth performance. Both experiments were vs. LIGHT × fat interaction, P  =  0.03), but in- conducted in a 2 × 3 factorial arrangement with creased (P  <  0.05) ADG regardless of sort cat- main effects of dietary fat addition (0 or 6% egory in experiment 2.  In both experiments, choice white grease) and sort weight category HEAVY pigs had greater (P < 0.05) overall ADG (HEAVY, LIGHT, or MIXED). In experiment and average daily feed intake (ADFI), but de- 1, 1,032 pigs (initially 30.7  kg) were individu- creased (P  <  0.05) G:F compared with LIGHT ally weighed and sorted into two body weight pigs. However, when HEAVY and LIGHT treat- (BW) groups with one group consisting of pigs ment groups were combined, growth perform- greater than median BW and the other group less ance and carcass characteristics were similar to than median BW. Pens were then formed by ran- MIXED pigs. Sorting decreased coefficient of domly selecting pigs: 1)  only from heavy group variation (CV) of final BW but did not affect CV (HEAVY), 2)  only from light group (LIGHT), of ADG. In conclusion, because adding fat to the or 3) from both heavy and light groups to create diets of lightweight pigs improved ADG in both a normal distribution around barn BW mean experiments, dietary fat could be used selectively (simulation of unsorted pigs; MIXED). In ex- in the barn to increase the weight of the lightest periment 2, 1,176 pigs (initially 35.1  kg) were 50% of the pigs. However, the sorting pigs into visually sorted into BW groups and assigned light and heavy weight groups did not improve to HEAVY, LIGHT, and MIXED pen weight growth performance or carcass characteristics. Key words: dietary fat, growth, sorting, pigs, weight variation Published by Oxford University Press on behalf of the American Society of Animal Science 2019. This work is written by (a) US Government employee(s) and is in the public domain in the US. This Open Access article contains public sector information licensed under the Open Government Licence v2.0 (http://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/). Transl. Anim. Sci. 2019.XX:0-0 doi: 10.1093/tas/txz162 Contribution no. 20-034-J from Kansas Agricultural Ex- INTRODUCTION periment Station, Manhattan 66506. The authors would like The competitiveness of the modern swine in- to thank New Horizon Farms, Pipestone, MN, for providing dustry dictates that feed, labor, and facilities must facilities and support for these experiments. 2 be utilized efficiently. The importance of growth Corresponding author: Goodband@ksu.edu. rate has increased with the adoption of all-in, Received August 2, 2019. Accepted October 4, 2019. all-out technology to improve facility utilization 1 Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 2 Chad et al. and increase profitability (Ice et al., 1999; Losinger ventilation during the summer and mechanically et al., 1999, Patience et al., 2004). During the mar- assisted ventilation during the winter. Treatments keting period of all-in, all-out finishing facilities, were arranged as a 2 × 3 factorial. Main effects in- normal distribution of the population dictates that cluded dietary fat addition (0 or 6% added choice lightweight pigs, or those weighing below packer white grease) and sorting of pigs into three weight minimum weight standards, will be present. Packer categories (HEAVY, LIGHT, or MIXED). matrices impose large discounts for lightweight pigs (Payne et al., 1999; Patience et al., 2004). Therefore, Experiment 1 any technology or management technique that re- This experiment began in the spring with 1,032 duces the number of lightweight pigs will result in gilts (L337  × 1050, PIC, Hendersonville, TN; ini- a greater economic return. There are two methods tially 30.7  kg). Pigs were individually tagged with to decrease the number of lightweight pigs without 3 cm round electronic identification tags (EID) with increasing days on feed. The first method is to re- unique 15-digit code. Pigs were weighed individu- duce the amount of variation within the popula- ally and divided into two body weight (BW) groups; tion. However, reducing the amount of variation the heavy group consisted of pigs with BW greater is difficult to achieve (van Barneveld and Hewitt, than barn median, and the light group contained 2016; López-Vergé et al., 2018). A second method pigs less than median BW. Pens were then formed by of reducing variation is by increasing the growth selecting pigs: 1) only from heavy group (HEAVY), rate of the lightest pigs, thus shifting this portion 2) only from light group (LIGHT), or 3) from both of the population to heavier weights. The addition heavy and light groups to create a normal distribu- of dietary fat has been shown to increase average tion around barn BW mean (MIXED). There were daily gain (ADG) in commercial field conditions 24 or 25 pigs per pen and 7 pens per treatment. Pens (Benz et al., 2011; Kellner et al., 2014; Stephenson of pigs were weighed and feed disappearance deter- et al., 2016). Thus, our objective was to determine mined approximately every 14 d during the entire whether adding dietary fat to diets of the lightest experiment. Individual pig weights were recorded 50% of the population in a finishing barn would re- at the beginning, approximately 8  wk after the sult in ADG similar to the heaviest pigs fed diets start of experiment (day 56), approximately 3  wk without added fat. The second objective was to de- before the conclusion (day 88), and at the conclu- termine if adding dietary fat influenced the CV for sion of the experiment (day 109). In conjunction ADG within heavy- or lightweight pigs. with the third individual weigh period, two heaviest pigs from HEAVY pens and the heaviest pig from MATERIALS AND METHODS MIXED pens were visually selected, removed, and The Kansas State University Institutional marketed as per commercial production practices. Animal Care and Use Committee approved all ex- At the end of the experiment, pigs from each pen perimental protocols used in this study. were individually tattooed and shipped to a com- mercial processing plant (Swift, Inc., Worthington, MN) where standard carcass criteria (loin and fat General depth, hot carcass weight, dressing percentage, lean In both experiments, diets were prepared in percentage, and fat-free-lean index) were measured. three phases and fed in meal form (Table 1). Amino acid levels were set at requirement estimates that Experiment 2 were previously demonstrated to maximize per- formance for pigs of the same genetic line in the This experiment started in the subsequent fall same facilities (Main et al., 2008). A constant lysine with 1,176 gilts (L337 × 1050, PIC, Hendersonville, to metabolizable energy (ME) ratio was maintained TN; initially 35.1 kg). Pigs were individually tagged within each phase with the ratios of 3.1, 2.5, and with 3  cm round EID tags as in experiment 1.  Pigs 2.6 g lysine/Mcal ME in the three phases, respect- were then visually sorted into weight groups around ively. Both experiments were conducted in 12.5  × the population mean and then sorted into weight treat- 76.2 m barns in southwestern Minnesota. The barns ments (HEAVY, LIGHT, and MIXED) with 28 pigs contained 48 pens (3.05 × 5.49 m). Each pen con- per pen. For the duration of the experiment, pens of tained one 4-hole dry feeder and two cup waterers. pigs were weighed and feed disappearance determined The curtain-sided barn has a deep pit, with com- every 14 d.  Individual pig weights were recorded at pletely slatted floors, and operates on natural the beginning (after allotment), approximately 7 wk Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 Adding fat to diets of pigs sorted by weight 3 Table 1. Diet composition (experiment 1 and 2; as-fed basis) 1 2 3 Phase 1 Phase 2 Phase 3 Item added fat: 0% 6% 0% 6% 0% 6% Ingredient, % Corn 68.70 58.64 75.82 66.26 75.28 65.75 Soybean meal, 46.5% CP 28.92 32.91 22.02 25.49 22.73 26.18 Choice white grease — 6.00 — 6.00 — 6.00 l -lysine HCl 0.15 0.15 0.15 0.15 0.15 0.15 Monocalcium P, 21% P 0.73 0.85 0.60 0.75 0.50 0.58 Ground limestone 0.85 0.80 0.80 0.80 0.80 0.80 Salt 0.35 0.35 0.35 0.35 0.35 0.35 Vitamin premix 0.15 0.15 0.13 0.10 0.08 0.08 Trace mineral premix 0.15 0.15 0.13 0.10 0.08 0.08 Ractopamine HCl — — — — 0.03 0.03 Total 100.00 100.00 100.00 100.00 100.00 100.00 Calculated nutrient composition Standardized ileal digestible lysine, % 1.01 1.09 0.84 0.91 0.86 0.93 Metabolizable energy (ME), Mcal/kg 3.29 3.57 3.31 3.58 3.31 3.59 Lysine:ME, g/Mcal 3.06 3.06 2.55 2.55 2.59 2.59 Crude protein, % 19.60 20.68 16.90 17.77 17.19 18.05 Calcium, % 0.61 0.63 0.55 0.57 0.51 0.54 Phosphorous, % 0.54 0.57 0.48 0.51 0.46 0.48 Phase 1 diets fed day 0 to 42 in experiment 1 and day 0 to 49 in experiment 2. Phase 2 diets fed day 42 to 88 in experiment 1 and day 49 to 81 in experiment 2. Phase 3 diets fed 88 to 109 in experiment 1 and day 81 to 95 in experiment 2. Vitamin premix provided per kg of complete feed: 27,558 IU vitamin A, from vitamin A 650; 4,133.6 IU vitamin D3 from vitamin D3 400; 110.2 IU vitamin E from vitamin E 50%; 11.0 mg vitamin K from MPB 100%; 0.10 mg B12 from vitamin B12 600; 24.8 mg riboflavin from riboflavin 95%; 82.7 mg pantothenic acid from d-Cal Pan 100% and 137.8 mg of niacin from niacin 99.5%. Trace mineral premix provided per kg of complete feed:165.3 g Zn from ZnO; 165.3 g Fe from FeSO ; 39.7 g Mn from MnO; 16.5 g Cu from CuSO ; 0.30 mg I from CaI O ; and 0.30 mg Se from NaSeO . 4 2 6 4 after the start of experiment (day 49), approximately HEAVY vs. LIGHT treatments, and their inter- 3 wk before the conclusion (day 81), and at the con- action with dietary fat addition. clusion of the experiment (day 95). Similar to the first experiment, the two heaviest pigs from HEAVY pens RESULTS and the heaviest pig from MIXED pens were visually selected and removed at the third weigh period. At Experiment 1 the end of the experiment, pigs from each pen were The addition of fat to diets increased (P < 0.05) individually tattooed and shipped to the same pro- ADG from day 0 to 56 (0.72 vs. 0.70 kg/d) and from cessing plant where the standard carcass criteria were day 56 to 88 (0.86 vs. 0.83 kg/d; Table 2). From day measured as in experiment 1. 88 to 109 and during the overall study, there was a HEAVY vs. LIGHT × fat interaction (P < 0.05) for ADG. This occurred because ADG increased when Statistical Analysis fat was added to diets for LIGHT pigs, but not when Data from both experiments were analyzed as fat was added to diets for HEAVY pigs. Adding fat a completely randomized design with pen as the to the diet reduced (P  <  0.01) average daily feed experimental unit. Analysis of variance was per- intake (ADFI) and increased (P  <  0.01) gain:feed formed using the MIXED procedure of SAS (SAS ratio (G:F) during each period. A  HEAVY vs. Institute, Inc., Cary, NC). Single degree-of-freedom LIGHT × fat interaction (P < 0.05) for ADFI was contrasts were used to determine the main effects observed from day 88 to 109 and the overall study. of dietary fat addition and sort weight category as This appeared to be the result of a greater reduc- well as their interaction on growth performance. tion in ADFI for HEAVY vs. LIGHT pigs when fat Preplanned nonorthogonal contrasts were also was added (P < 0.01). used to compare the sorted (HEAVY and LIGHT The addition of fat to diets increased (P = 0.03) pens combined) vs. unsorted (MIXED) treatments, day 88 BW (99.4 vs. 97.6 kg) but had no effect on Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 4 Chad et al. Table 2. Effects of added fat and initial sort on growth performance of finishing pigs (experiment 1) 0% 6% Main effect P-value Interaction P-value Added dietary fat: HEAVY HEAVY vs. Sorted vs. vs. Sorted vs. LIGHT MIXED Sort category: HEAVY LIGHT MIXED HEAVY LIGHT MIXED SEM Fat LIGHT MIXED by fat by fat Average daily gain, kg day 0 to 56 0.75 0.64 0.70 0.77 0.69 0.71 0.014 0.04 0.01 0.42 0.27 0.45 day 56 to 88 0.85 0.82 0.82 0.87 0.84 0.85 0.012 0.02 0.06 0.50 1.00 0.68 day 88 to 109 1.07 0.98 1.00 1.00 1.00 1.01 0.021 0.35 0.10 0.65 0.04 0.28 Overall 0.84 0.77 0.80 0.83 0.80 0.81 0.009 0.08 0.01 0.51 0.03 0.66 Average daily feed intake, kg day 0 to 56 1.83 1.47 1.64 1.69 1.43 1.52 0.032 0.01 0.01 0.33 0.10 0.73 day 56 to 88 2.64 2.30 2.44 2.37 2.17 2.24 0.039 0.01 0.01 0.37 0.11 0.99 day 88 to 109 3.02 2.67 2.77 2.60 2.44 2.56 0.044 0.01 0.01 0.63 0.03 0.13 Overall 2.26 1.93 2.06 2.03 1.82 1.91 0.031 0.01 0.01 0.41 0.05 0.76 Gain:feed ratio day 0 to 56 0.41 0.43 0.42 0.45 0.48 0.46 0.006 0.01 0.01 0.56 0.76 0.79 day 56 to 88 0.32 0.35 0.34 0.36 0.38 0.38 0.006 0.01 0.01 0.22 0.12 0.12 day 88 to 109 0.36 0.37 0.36 0.38 0.41 0.39 0.007 0.01 0.02 0.99 0.25 0.99 Overall 0.36 0.39 0.38 0.41 0.43 0.42 0.004 0.01 0.01 0.89 0.90 0.45 A total of 1,032 gilts (24 or 25 pigs per pen and 7 pens per treatment) with an initial average weight of 30.7 kg. Pigs were sorted based on body weight at placement. HEAVY, pig from the heaviest 50% of the population; LIGHT, pig from the lightest 50% of the population; MIXED, pigs from the whole population with normal distribution around body weight mean. Mean of combined HEAVY and LIGHT treatment groups. final BW (119.2 vs. 118.0 kg), CV of individual BW (P < 0.01) ADFI but increased (P < 0.01) G:F dur- (11.8 vs. 11.0%), or CV of ADG (14.1 vs. 13.3%; ing each period. Table 3). There was no evidence for difference (P > Pigs from the HEAVY category had increased 0.42) among pigs fed diets with or without added (P < 0.05) ADG and ADFI, but decreased (P < 0.01) fat on back fat, fat-free lean index, percent lean, or G:F, compared with the LIGHT category during loin depth. each growth period, except for ADG from day 49 For the effects of BW sorting, HEAVY pigs had to 81 and G:F from day 81 to 95. However, when greater BW compared with LIGHT pigs during each combining the HEAVY and LIGHT treatment period, but when combined, the average weight of groups, pigs from the SORTED pens had similar sorted pigs (HEAVY and LIGHT) was similar (P > ADG, ADFI, and G:F compared with MIXED (P 0.40) to the MIXED pigs. There was a HEAVY vs. > 0.25). LIGHT × fat interaction (P  =  0.05) for final BW, Adding dietary fat increased (P  <  0.01) BW which occurred because BW was increased when fat at the end of each period (Table 5). However, was added to diets for LIGHT pigs, but not when adding fat had no effect (P > 0.41) on CV of BW fat was added to diets for HEAVY pigs. Pigs sorted in any period. Feeding pigs diets with fat reduced into HEAVY pens maintained lower (P = 0.05) BW (P < 0.01) CV of ADG from day 49 to 81 (15.3 vs. CV compared with that of LIGHT pens throughout 12.6%); however, this response was not observed (P the study. Furthermore, sorted pigs had decreased > 0.64) in other periods. (P < 0.10) BW CV throughout the study compared Pigs from the HEAVY category maintained with the MIXED pigs. However, sorting had no ef- greater (P  <  0.01) BW with lower (P  <  0.01) CV fect (P > 0.38) on CV of ADG or carcass traits. compared with those from the LIGHT category throughout the experiment. There was a HEAVY vs. LIGHT × fat interaction (P  <  0.10) for BW Experiment 2 CV on day 49 and 81. This seemed to be a mag- No sort category × fat interaction was ob- nitude effects because in diets without added fat, served for any growth responses (P > 0.26). Pigs fed BW CV was greater in LIGHT pigs than HEAVY, diets with added fat had greater (P  <  0.01) ADG but adding fat to diets had only a modest in- from day 0 to 49 and for the overall experimental crease in BW CV among HEAVY and LIGHT period (Table 4). Adding fat to the diets decreased pigs. When combining the HEAVY and LIGHT Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 Adding fat to diets of pigs sorted by weight 5 Table 3. Effects of added fat and initial sort on weight variation, carcass traits in finishing pigs (experiment 1) Added dietary fat: 0% 6% Main effect P-value Interaction P-value HEAVY vs. Sorted vs. HEAVY vs. Sorted vs. LIGHT MIXED Sort category: HEAVY LIGHT MIXED HEAVY LIGHT MIXED SEM Fat LIGHT MIXED by fat by fat Pig weight, kg day 0 34.68 26.79 30.80 34.72 26.79 30.63 0.330 0.88 0.01 0.91 0.95 0.75 day 56 77.62 63.52 70.80 78.38 66.17 71.06 0.930 0.11 0.01 0.55 0.32 0.38 day 88 105.42 89.96 97.41 106.49 93.10 98.60 1.009 0.03 0.01 0.40 0.31 0.60 day 109 125.63 110.90 117.42 124.43 114.08 119.19 1.079 0.17 0.01 0.63 0.05 0.68 Pig weight, CV day 0 8.72 11.02 15.87 8.72 12.67 15.42 0.706 0.49 0.01 0.01 0.25 0.30 day 56 11.55 15.69 15.05 12.76 14.72 16.20 1.257 0.65 0.02 0.08 0.39 0.64 day 88 9.07 13.34 13.25 11.38 12.77 14.08 0.997 0.30 0.01 0.02 0.16 0.98 day 109 8.38 12.18 12.40 9.98 12.79 12.59 0.933 0.30 0.01 0.05 0.60 0.58 Average daily gain, CV day 0 to 56 18.61 23.68 20.09 19.75 20.35 21.23 2.184 0.85 0.44 0.97 0.31 0.56 day 56 to 88 14.52 14.41 17.35 15.21 17.11 17.33 1.312 0.30 0.18 0.08 0.45 0.45 day 88 to 109 19.06 17.74 22.47 18.99 21.75 18.60 2.526 0.99 0.84 0.60 0.42 0.19 Overall 10.83 14.54 14.48 12.89 15.18 14.14 1.236 0.44 0.05 0.38 0.57 0.43 Carcass traits Back fat, mm 14.99 14.15 14.44 15.02 14.41 14.59 0.013 0.59 0.10 0.66 0.75 1.00 Fat-free lean 51.63 51.30 51.53 51.53 51.35 51.58 0.153 0.98 0.20 0.46 0.63 0.80 index, % Lean, % 56.95 57.56 57.14 57.02 57.16 57.48 0.290 0.99 0.38 0.58 0.43 0.32 Loin depth, cm 6.02 6.11 5.90 6.11 5.91 6.27 0.134 0.42 0.85 0.70 0.30 0.07 A total of 1,032 gilts (24 or 25 pigs per pen and 7 pens per treatment) with an initial average weight of 30.7 kg. Pigs were sorted based on body weight at placement. HEAVY, pig from the heaviest 50% of the population; LIGHT, pig from the lightest 50% of the population; MIXED, pigs from the whole population with normal distribution around body weight mean. Mean of combined HEAVY and LIGHT treatment groups. Coefficient of variation. Values derived from processing plant. treatment groups, sorted pigs had similar BW, but et  al., 2018). Variation in growth is the result of decreased (P  <  0.01) CV of BW, compared with differences in health, genetic makeup, and social MIXED pigs throughout the study. A HEAVY vs. interactions. Days to market for a group of pigs is LIGHT × fat interaction (P = 0.03) was observed dictated by the growth rate of the lightest 50% of for CV of ADG from day 0 to 49. This response the pigs in the barn because they must reach a min- occurred because CV of ADG increased when fat imum weight to reduce sort discount by the pro- fed to HEAVY pigs, while adding fat to diets for cessor. Thus, within a population of pigs, increasing LIGHT pigs decreased CV of ADG. The influence the ADG has more value in lightweight pigs than of sorting on CV of ADG was inconsistent with their heavy weight counter parts. a response observed from day 0 to 49 and day 81 Energy is important because it is the most ex- to 95 (P < 0.05), but not from day 49 to 81 or the pensive component of the diet, and it has a signifi- overall trial. cant impact on animal performance and nutrient utilization. Increasing dietary energy, such as with addition of dietary fat, is one of the few nu- DISCUSSION tritional tools available to increase ADG for pigs Lightweight pigs are a costly problem in all-in, fed an otherwise nutritionally adequate diet. In all-out swine production. Variation in growth is commercial swine production, dietary energy level costly because it increases the penalty for sort loss, often limits ADG (De la Llata et al., 2001b). Many increases the number of days to bring lightweight studies have shown that the addition of dietary fat pigs to market weights, and results in extra facility to corn-soybean meal-based diets increases ADG cost (van Barneveld and Hewitt, 2016; López-Vergé and G:F (Benz et  al., 2011; Kellner et  al., 2014; Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 6 Chad et al. Table 4. Effects of added fat and initial sort on growth performance of finishing pigs (experiment 2) Added dietary fat: 0% 6% Main effect P-value Interaction P-value HEAVY HEAVY vs. Sorted vs. vs. Sorted vs. LIGHT MIXED Sort category: HEAVY LIGHT MIXED HEAVY LIGHT MIXED SEM Fat LIGHT MIXED by fat by fat Average daily gain, kg day 0 to 49 0.83 0.79 0.81 0.86 0.83 0.85 0.010 0.01 0.01 0.89 0.40 0.81 day 49 to 81 0.94 0.93 0.93 0.95 0.96 0.95 0.058 0.16 0.96 0.80 0.77 0.83 day 81 to 95 1.02 0. 90 0.95 1.05 0.93 0.97 0.045 0.43 0.04 0.75 0.99 0.88 Overall 0.88 0.85 0.87 0.91 0.89 0.90 0.008 0.01 0.02 0.91 0.37 0.89 Average daily feed intake, kg day 0 to 49 2.12 1.93 2.03 1.98 1.80 1.90 0.025 0.01 0.01 0.83 0.84 0.99 day 49 to 81 2.64 2.49 2.57 2.45 2.28 2.36 0.032 0.01 0.01 0.94 0.82 0.84 day 81 to 95 3.07 2.83 2.99 2.89 2.57 2.68 0.048 0.01 0.01 0.99 0.40 0.26 Overall 2.70 2.28 2.46 2.51 2.09 2.27 0.025 0.01 0.01 0.25 0.91 0.97 Gain:feed ratio day 0 to 49 0.39 0.41 0.40 0.43 0.46 0.45 0.005 0.01 0.01 0.93 0.30 0.67 day 49 to 81 0.35 0.37 0.36 0.39 0.42 0.41 0.009 0.01 0.01 0.78 0.75 0.52 day 81 to 95 0.33 0.32 0.32 0.36 0.36 0.36 0.012 0.01 0.86 0.75 0.67 0.86 Overall 0.36 0.38 0.37 0.41 0.43 0.42 0.004 0.01 0.01 0.68 0.28 0.83 A total of 1,176 gilts (28 pigs per pen and 7 pens per treatment) with an initial average weight of 35.1 kg. Pigs were sorted based on body weight at placement. HEAVY, pig from the heaviest 50% of the population; LIGHT, pig from the lightest 50% of the population; MIXED, pigs from the whole population with normal distribution around body weight mean. Mean of combined HEAVY and LIGHT treatment groups. Table 5. Effects of added fat and initial sort on weight variation, carcass traits in finishing pigs (experiment 2) Added dietary fat: 0% 6% Main effect P-value Interaction P-value HEAVY Sorted HEAVY Sorted vs. vs. vs. vs. LIGHT MIXED Sort category: HEAVY LIGHT MIXED HEAVY LIGHT MIXED SEM Fat LIGHT MIXED by fat by fat Pig weight, kg day 0 37.75 32.52 35.28 37.62 32.56 35.09 0.543 0.83 0.01 0.87 0.87 0.88 day 49 78.30 71.09 74.80 79.63 73.33 76.60 0.722 0.01 0.01 0.86 0.53 0.99 day 81 108.30 100.93 104.64 110.04 104.00 107.00 0.752 0.01 0.01 1.00 0.38 0.97 day 95 121.24 113.58 117.49 123.04 117.00 119.89 0.876 0.01 0.01 0.97 0.36 0.89 Pig weight, CV day 0 9.33 12.56 15.85 9.99 12.08 15.88 0.751 0.91 0.01 0.01 0.46 0.96 day 49 8.18 11.87 13.12 9.30 10.37 12.92 0.691 0.73 0.01 0.01 0.06 1.00 day 81 8.02 10.39 11.05 8.69 8.69 10.95 0.551 0.41 0.01 0.01 0.04 0.66 day 95 7.23 9.78 9.78 7.47 8.67 9.65 0.479 0.41 0.01 0.01 0.17 0.71 Average daily gain, CV day 0 to 49 10.68 15.00 14.78 13.03 12.58 14.36 1.028 0.84 0.04 0.06 0.03 0.83 day 49 to 81 15.61 15.80 14.55 14.21 10.82 12.69 1.134 0.01 0.33 0.62 0.12 0.50 day 81 to 95 18.92 27.30 18.69 19.23 23.07 21.02 1.766 0.72 0.01 0.15 0.21 0.17 Overall 8.86 10.64 9.79 9.44 9.41 9.74 0.612 0.64 0.34 0.74 0.15 0.80 A total of 1,176 gilts (28 pigs per pen and 7 pens per treatment) with an initial average weight of 35.1 kg. Pigs were sorted based on body weight at placement. HEAVY, pig from the heaviest 50% of the population; LIGHT, pig from the lightest 50% of the population; MIXED, pigs from the whole population with normal distribution around body weight mean. Mean of combined HEAVY and LIGHT treatment groups. Coefficient of variation. Stephenson et  al., 2016). In general, for every 1% Llata et  al., 2001b), although the improvements added dietary fat in a corn-soybean meal based can be greater. Benz et  al. (2011) observed a 9% diet, ADG is expected to increase 1% and G:F improvement in ADG (0.97 vs. 0.89 kg) for pigs fed is expected to improve approximately 2% (De la 5% added fat and Kellner et  al. (2014) evaluated Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 Adding fat to diets of pigs sorted by weight 7 100% 90% MIXED (no fat addition) MIXED (with fat addition) 80% HEAVY (no fat) + LIGHT (with fat) 70% 60% 50% 40% 30% 20% 10% 0% 70 80 90 100110 120130 140150 Body weight, kg Figure 1. Cumulative sum graph showing percentage of population over BW range. Pigs were sorted based on BW at placement. HEAVY, pig from the heaviest 50% of the population; LIGHT, pig from the lightest 50% of the population; MIXED, pigs from the whole population with normal distribution around BW mean. The graph represents three scenarios: 1) no added fat fed to MIXED pigs, 2) added fat fed to MIXED pigs, or 3) added fat fed to LIGHT pigs but not for HEAVY pigs. the addition of 6% of different fat sources and either with or without added fat. Using individual found up to 20% greater ADG (1.12 vs. 0.93 kg/d). weights from these treatments in both studies, a cu- However, the environment and housing (individual mulative sum graph was created (Figure 1) to rep- vs. pen) must be considered when comparing re- resent the portion of the population that would be sults. Patience (2001) calculated that, reducing en- at or below a specific weight. As the graph illus- ergy intake by 1% resulted in a decrease in growth trates, adding fat to the diet for the mixed popu- rate of about 1.2%. They also calculated that for lation simply shifts the population to the right each 1% reduction in energy intake, market weights resulting in fewer pigs being lower than the desired would be lowered by approximately 1  kg. In our weight range for the packer. Unfortunately, this studies, adding 6% fat in diets for LIGHT pigs shift of the curve for the mixed population also re- increased ADG by 3.9% in experiment 1.  In con- sults in more pigs being heavier than the optimal trast, HEAVY pigs had a slight decrease in ADG weight range for the packer when fat is added to (0.83 vs. 0.84 kg/d) when fed diets with added fat. the diet. If pigs would be sorted at the beginning This was unexpected and prompted us to conduct of the finisher with the lightest 50% of pigs fed the second study. In experiment 2, adding fat in higher energy diets and the heaviest 50% of pigs the diets increased ADG by 3.4% for HEAVY and fed lower energy diets, dietary fat could be fed to 4.7% for LIGHT pigs. Regardless, the magnitude only the lightweight population that needed the of the response for increasing ADG by adding fat extra weight gain. This situation is simulated in the was greater for LIGHT pigs than HEAVY pigs in combined group in Figure 1. Using this approach, both experiments. the lower end of the curve is shifted to the right The increase in weight in light pigs from adding because adding dietary fat increased ADG for the dietary fat moved a larger number of lightweight lightweight pigs. The upper end of the curve is not pigs closer and into the packers marketing window. shifted to the right because the heavy pigs would be For pigs heavier than the population mean, pro- fed the lower energy diet without added fat. This il- viding additional energy will increase market lustrates that an initial sorting in conjunction with weight and move a larger portion of pigs out of feeding two different dietary energy treatments the optimal weight range for the packer and in- may be effective in moving a higher percentage of crease sort discounts. A secondary analysis of our the pigs into the packer’s ideal marketing grid. In data was performed to evaluate the implications addition, it is important to note that the economics of feeding the lightest 50% of the population diets of adding fat to finishing diets depend on the de- with added fat while feeding diets without added sign of the production system as well as the prices fat to the heaviest 50% of the population. This of corn, soybean meal, fat, and carcass price. For population (combined) was then compared with instance, the value of the additional weight will the unsorted mixed populations that were fed diets depend on the availability of finishing space. If Translate basic science to industry innovation Percent of thepopulation, % Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 8 Chad et al. extra space already exists, the increase in ADG is improve growth performance. Sorting decreased worth only fewer days in the facility. When space BW variation, but not ADG variation, within a is limited, increasing the ADG is worth the extra population. weight sold at market (De la Llata et al., 2001a). Conflict of interest statement. None declared. Many producers try to minimize variation and discounts by sorting pigs into more uniform weight LITERATURE CITED groups at placement into the finishing barn. Several van Barneveld, R. J. and R. J. E. Hewitt. 2016. Reducing vari- studies (Brumm et  al. 2002; Wolter et  al., 2002; ation in pork production systems through maternal and Cámara et al., 2016) have reported that sorting pigs pre- and post-weaning nutrition strategies. Anim. Prod. Sci. 56:1248–1253. https://doi.org/10.1071/AN15396 into uniform weight pens did not improve overall Benz,  J.  M., M.  D.  Tokach, S.  S.  Dritz, J.  L.  Nelssen, performance. The present study was designed to J.  M.  DeRouchey, R.  C.  Sulabo, and R.  D.  Goodband. simulate the field scenarios where feeder pigs were 2011. Effects of increasing choice white grease in corn- sorted into two weight categories (HEAVY vs. and sorghum-based diets on growth performance, carcass LIGHT). In addition to the comparison between characteristics, and fat quality characteristics of finishing HEAVY vs. LIGHT categories, contrasts were also pigs. J. Anim. Sci. 89:773–782. doi:10.2527/jas.2010–3033 Brumm,  M.  C., and P.  S.  Miller. 1996. Response of pigs to performed to compare the combination of HEAVY space allocation and diets varying in nutrient density. J. and LIGHT treatment groups (referred as “sorted”) Anim. Sci. 74:2730–2737. doi:10.2527/1996.74112730x to MIXED (unsorted) pigs. This was done to de- Brumm,  M.  C., M.  Ellis, L.  J.  Johnston, D.  W.  Rozeboom, termine whether the sorting practice improved pig and D.  R.  Zimmerman; NCR-89 Committee on Swine performance. Results from both experiments sug- Management. 2002. Effect of removal and remixing of lightweight pigs on performance to slaughter weights. J. gested that even though heavier pigs maintained Anim. Sci. 80:1166–1172. doi:10.2527/2002.8051166x greater ADG than lighter pigs, the combination of Cámara, L., J. D. Berrocoso, A. Fuentetaja, C. J. López-Bote, sorted pigs had the same ADG, ADFI, and G:F C.  de  Blas, and G.  G.  Mateos. 2016. Regrouping of pigs as that of unsorted pigs. In experiment 2, there by body weight at weaning does not affect growth per- was an inconsistent response of sorting on CV of formance, carcass quality or uniformity at slaughter of ADG. This effect of sorting was not observed in heavy weight pigs. Anim. Sci. J. 87:134–142. doi:10.1111/ asj.12404 experiment 1.  Magowan et  al. (2011) found lower De la Llata, M., S. S. Dritz, M. R. Langemeier, M. D. Tokach, BW CV at 10 and 15 wk of age for pigs in uniform R. D. Goodband, and J. L. Nelssen. 2001a. Economics of weight groups compared to mixed weight groups. increasing lysine:calorie ratio and adding dietary fat for Conversely, O’Connell et al. (2005) determined that grow-finishing pigs reared in a commercial environment. the formation of uniform groups at 4  wk of age J. Swine Healt. Prod. 5:215–223. De la Llata, M., S. S. Dritz, M. D. Tokach, R. D. Goodband, did not affect 21  wk of age BW CV. Brumm and J.  L.  Nelssen, and T.  M.  Loughin. 2001b. Effects of Miller (1996) also found an inconsistent influence dietary fat on growth performance and carcass char- of added dietary fat on CV of final weight with acteristics of growing-finishing pigs reared in a com- added fat having no influence on CV in one experi- mercial environment. J. Anim. Sci. 79:2643–2650. ment, but increasing CV in the second experiment. doi:10.2527/2001.79102643x Sorting pigs at or near time of marketing can re- Ice, A. D., A. L. Grant, L. K. Clark, T. R. Cline, M. E. Einstein, T.  G.  Martin, and M.  A.  Diekman. 1999. Health and duce sort discounts received from packers; however, growth performance of barrows reared in all-in/all-out or the remained pigs in the facility assume greater fa- continuous flow facilities with or without a chlortetracyc- cility cost and reduce profitability. Thus, it is critical line feed additive. Am. J. Vet. Res. 60:603–608. to increase ADG of lightweight pigs in conjunction Kellner, T. A., K. J. Prusa, and J. F. Patience. 2014. Impact of with sorting. dietary fat source and concentration and daily fatty acid intake on the composition of carcass fat and iodine value In summary, because adding fat to the diets sampled in three regions of the pork carcass. J. Anim. Sci. of lightweight pigs improved ADG in both ex- 92:5485–5495. doi:10.2527/jas.2014-7567 periments, dietary fat could be used selectively in López-Vergé,  S., J.  Gasa, M.  Farré, J.  Coma, J.  Bonet, and the barn to increase the weight of the lightest 50% D.  Solà-Oriol. 2018. Potential risk factors related to pig of the pigs. Moreover, feeding additional dietary body weight variability from birth to slaughter in com- fat did not affect the variation in BW or ADG. mercial conditions. Trans. Anim. Sci. 2:383–395. https:// doi.org/10.1093/tas/txy082 By increasing dietary fat fed to the light pigs and Losinger,  W.  C., E.  J.  Bush, M, A. Smith, and B.  A.  Corso. removing fat from diets of heavy pigs, producers 1999. Mortality of grower/finisher-only swine operations may be able to increase the percentage of pigs in the United States. Arq. Bras. Med. Vet. Zootec. 51:141– marketed within the packers’ ideal grid. These 147. doi:10.1590/S0102-09351999000200003 studies also show that sorting feeder pigs based Magowan, E., M. E. E. Ball, K. J. McCracken, V. E. Beattie, R. Bradford, M. J. Robinson, M. Scott, F. J. Gordon, and on initial BW when placing into finishers did not Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 Adding fat to diets of pigs sorted by weight 9 C.  S.  Mayne. 2011. Effect of dietary regime and group advances in pork production. Proceedings of the Banff structure on pig performance and the variation in weight Pork Seminar, Adv. Pork Product. 15:257–266. and growth rate from weaning to 20 weeks of age. Livest. Payne, H. G., B. P. Mullan, M. Trezona, and B. Frey. 1999. A Sci. 136:216–224. doi:10.1016/j.livsci.2010.09.013 review—variation in pig production and performance. In: Main,  R.  G., S.  S.  Dritz, M.  D.  Tokach, R.  D.  Goodband, P.D.  Cranwell, editor. Manipulating Pig Production VII. and J.  L.  Nelssen. 2008. Determining an optimum Australasian Pig Science Association, Werribee, Victoria, lysine:calorie ratio for barrows and gilts in a com- Australia; p 13–26. mercial finishing facility. J. Anim. Sci. 86:2190–2207. Stephenson,  E.  W., M.  A.  Vaughn, D.  D.  Burnett, doi:10.2527/jas.2007-0408 C. B. Paulk, M. D. Tokach, S. S. Dritz, J. M. DeRouchey, O’Connell,  N.  E., V.  E.  Beattie, and D.  Watt. 2005. Influence R. D. Goodband, J. C. Woodworth, and J. M. Gonzalez. of regrouping strategy on performance, behaviour and 2016. Influence of dietary fat source and feeding duration carcass parameters in pigs. Livest. Prod. Sci. 97:107–115. on finishing pig growth performance, carcass composition, doi:10.1016/j.livprodsci.2005.03.005 and fat quality. J. Anim. Sci. 94:2851–2866. doi:10.2527/ Patience,  J.  F. 2001. Factors driving average daily gain. In: jas.2015-9521 Average Daily Gain: How Do I Get It and Can I Afford It? Wolter, B. F., M. Ellis, S. E. Curtis, E. N. Parr, and D. M. Webel. Proc. Ann. Mtg., Amer. Assoc. Swine Practit.; February 2002. Effects of feeder-trough space and variation in body 24 to 28, 2001; Nashville (TN); p. 5–11. weight within a pen of pigs on performance in a wean- Patience, J. F., K. Engele, A. D. Beaulieu, H. W. Gonyou, and to-finish production system. J. Anim. Sci. 80:2241–2246. R. T. Zijlstra. 2004. Variation: costs and consequences. In: doi:10.1093/ansci/80.9.2241 Translate basic science to industry innovation http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Translational Animal Science Oxford University Press

Effects of added fat on growth performance of finishing pigs sorted by initial weight

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Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 Effects of added fat on growth performance of finishing pigs sorted by initial weight ,‡ †, ,2 Chad W. Hastad,* Mike D. Tokach,* Steve S. Dritz, Robert D. Goodband,* ,$ Joel M. DeRouchey,* and Fangzhou Wu* *Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS 66506-0210; Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State ‡ $ University, Manhattan, KS 66506-0210; Present address: New Fashion Pork, Jackson, MN.; and Present address: Pipestone System, Pipestone, MN. ABSTRACT: Two studies were conducted to categories. Overall in experiment 1, adding 6% determine whether dietary fat fed to pigs of dif- dietary fat increased average daily gain (ADG) ferent weight categories differentially influences of LIGHT pigs, but not HEAVY pigs (HEAVY growth performance. Both experiments were vs. LIGHT × fat interaction, P  =  0.03), but in- conducted in a 2 × 3 factorial arrangement with creased (P  <  0.05) ADG regardless of sort cat- main effects of dietary fat addition (0 or 6% egory in experiment 2.  In both experiments, choice white grease) and sort weight category HEAVY pigs had greater (P < 0.05) overall ADG (HEAVY, LIGHT, or MIXED). In experiment and average daily feed intake (ADFI), but de- 1, 1,032 pigs (initially 30.7  kg) were individu- creased (P  <  0.05) G:F compared with LIGHT ally weighed and sorted into two body weight pigs. However, when HEAVY and LIGHT treat- (BW) groups with one group consisting of pigs ment groups were combined, growth perform- greater than median BW and the other group less ance and carcass characteristics were similar to than median BW. Pens were then formed by ran- MIXED pigs. Sorting decreased coefficient of domly selecting pigs: 1)  only from heavy group variation (CV) of final BW but did not affect CV (HEAVY), 2)  only from light group (LIGHT), of ADG. In conclusion, because adding fat to the or 3) from both heavy and light groups to create diets of lightweight pigs improved ADG in both a normal distribution around barn BW mean experiments, dietary fat could be used selectively (simulation of unsorted pigs; MIXED). In ex- in the barn to increase the weight of the lightest periment 2, 1,176 pigs (initially 35.1  kg) were 50% of the pigs. However, the sorting pigs into visually sorted into BW groups and assigned light and heavy weight groups did not improve to HEAVY, LIGHT, and MIXED pen weight growth performance or carcass characteristics. Key words: dietary fat, growth, sorting, pigs, weight variation Published by Oxford University Press on behalf of the American Society of Animal Science 2019. This work is written by (a) US Government employee(s) and is in the public domain in the US. This Open Access article contains public sector information licensed under the Open Government Licence v2.0 (http://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/). Transl. Anim. Sci. 2019.XX:0-0 doi: 10.1093/tas/txz162 Contribution no. 20-034-J from Kansas Agricultural Ex- INTRODUCTION periment Station, Manhattan 66506. The authors would like The competitiveness of the modern swine in- to thank New Horizon Farms, Pipestone, MN, for providing dustry dictates that feed, labor, and facilities must facilities and support for these experiments. 2 be utilized efficiently. The importance of growth Corresponding author: Goodband@ksu.edu. rate has increased with the adoption of all-in, Received August 2, 2019. Accepted October 4, 2019. all-out technology to improve facility utilization 1 Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 2 Chad et al. and increase profitability (Ice et al., 1999; Losinger ventilation during the summer and mechanically et al., 1999, Patience et al., 2004). During the mar- assisted ventilation during the winter. Treatments keting period of all-in, all-out finishing facilities, were arranged as a 2 × 3 factorial. Main effects in- normal distribution of the population dictates that cluded dietary fat addition (0 or 6% added choice lightweight pigs, or those weighing below packer white grease) and sorting of pigs into three weight minimum weight standards, will be present. Packer categories (HEAVY, LIGHT, or MIXED). matrices impose large discounts for lightweight pigs (Payne et al., 1999; Patience et al., 2004). Therefore, Experiment 1 any technology or management technique that re- This experiment began in the spring with 1,032 duces the number of lightweight pigs will result in gilts (L337  × 1050, PIC, Hendersonville, TN; ini- a greater economic return. There are two methods tially 30.7  kg). Pigs were individually tagged with to decrease the number of lightweight pigs without 3 cm round electronic identification tags (EID) with increasing days on feed. The first method is to re- unique 15-digit code. Pigs were weighed individu- duce the amount of variation within the popula- ally and divided into two body weight (BW) groups; tion. However, reducing the amount of variation the heavy group consisted of pigs with BW greater is difficult to achieve (van Barneveld and Hewitt, than barn median, and the light group contained 2016; López-Vergé et al., 2018). A second method pigs less than median BW. Pens were then formed by of reducing variation is by increasing the growth selecting pigs: 1) only from heavy group (HEAVY), rate of the lightest pigs, thus shifting this portion 2) only from light group (LIGHT), or 3) from both of the population to heavier weights. The addition heavy and light groups to create a normal distribu- of dietary fat has been shown to increase average tion around barn BW mean (MIXED). There were daily gain (ADG) in commercial field conditions 24 or 25 pigs per pen and 7 pens per treatment. Pens (Benz et al., 2011; Kellner et al., 2014; Stephenson of pigs were weighed and feed disappearance deter- et al., 2016). Thus, our objective was to determine mined approximately every 14 d during the entire whether adding dietary fat to diets of the lightest experiment. Individual pig weights were recorded 50% of the population in a finishing barn would re- at the beginning, approximately 8  wk after the sult in ADG similar to the heaviest pigs fed diets start of experiment (day 56), approximately 3  wk without added fat. The second objective was to de- before the conclusion (day 88), and at the conclu- termine if adding dietary fat influenced the CV for sion of the experiment (day 109). In conjunction ADG within heavy- or lightweight pigs. with the third individual weigh period, two heaviest pigs from HEAVY pens and the heaviest pig from MATERIALS AND METHODS MIXED pens were visually selected, removed, and The Kansas State University Institutional marketed as per commercial production practices. Animal Care and Use Committee approved all ex- At the end of the experiment, pigs from each pen perimental protocols used in this study. were individually tattooed and shipped to a com- mercial processing plant (Swift, Inc., Worthington, MN) where standard carcass criteria (loin and fat General depth, hot carcass weight, dressing percentage, lean In both experiments, diets were prepared in percentage, and fat-free-lean index) were measured. three phases and fed in meal form (Table 1). Amino acid levels were set at requirement estimates that Experiment 2 were previously demonstrated to maximize per- formance for pigs of the same genetic line in the This experiment started in the subsequent fall same facilities (Main et al., 2008). A constant lysine with 1,176 gilts (L337 × 1050, PIC, Hendersonville, to metabolizable energy (ME) ratio was maintained TN; initially 35.1 kg). Pigs were individually tagged within each phase with the ratios of 3.1, 2.5, and with 3  cm round EID tags as in experiment 1.  Pigs 2.6 g lysine/Mcal ME in the three phases, respect- were then visually sorted into weight groups around ively. Both experiments were conducted in 12.5  × the population mean and then sorted into weight treat- 76.2 m barns in southwestern Minnesota. The barns ments (HEAVY, LIGHT, and MIXED) with 28 pigs contained 48 pens (3.05 × 5.49 m). Each pen con- per pen. For the duration of the experiment, pens of tained one 4-hole dry feeder and two cup waterers. pigs were weighed and feed disappearance determined The curtain-sided barn has a deep pit, with com- every 14 d.  Individual pig weights were recorded at pletely slatted floors, and operates on natural the beginning (after allotment), approximately 7 wk Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 Adding fat to diets of pigs sorted by weight 3 Table 1. Diet composition (experiment 1 and 2; as-fed basis) 1 2 3 Phase 1 Phase 2 Phase 3 Item added fat: 0% 6% 0% 6% 0% 6% Ingredient, % Corn 68.70 58.64 75.82 66.26 75.28 65.75 Soybean meal, 46.5% CP 28.92 32.91 22.02 25.49 22.73 26.18 Choice white grease — 6.00 — 6.00 — 6.00 l -lysine HCl 0.15 0.15 0.15 0.15 0.15 0.15 Monocalcium P, 21% P 0.73 0.85 0.60 0.75 0.50 0.58 Ground limestone 0.85 0.80 0.80 0.80 0.80 0.80 Salt 0.35 0.35 0.35 0.35 0.35 0.35 Vitamin premix 0.15 0.15 0.13 0.10 0.08 0.08 Trace mineral premix 0.15 0.15 0.13 0.10 0.08 0.08 Ractopamine HCl — — — — 0.03 0.03 Total 100.00 100.00 100.00 100.00 100.00 100.00 Calculated nutrient composition Standardized ileal digestible lysine, % 1.01 1.09 0.84 0.91 0.86 0.93 Metabolizable energy (ME), Mcal/kg 3.29 3.57 3.31 3.58 3.31 3.59 Lysine:ME, g/Mcal 3.06 3.06 2.55 2.55 2.59 2.59 Crude protein, % 19.60 20.68 16.90 17.77 17.19 18.05 Calcium, % 0.61 0.63 0.55 0.57 0.51 0.54 Phosphorous, % 0.54 0.57 0.48 0.51 0.46 0.48 Phase 1 diets fed day 0 to 42 in experiment 1 and day 0 to 49 in experiment 2. Phase 2 diets fed day 42 to 88 in experiment 1 and day 49 to 81 in experiment 2. Phase 3 diets fed 88 to 109 in experiment 1 and day 81 to 95 in experiment 2. Vitamin premix provided per kg of complete feed: 27,558 IU vitamin A, from vitamin A 650; 4,133.6 IU vitamin D3 from vitamin D3 400; 110.2 IU vitamin E from vitamin E 50%; 11.0 mg vitamin K from MPB 100%; 0.10 mg B12 from vitamin B12 600; 24.8 mg riboflavin from riboflavin 95%; 82.7 mg pantothenic acid from d-Cal Pan 100% and 137.8 mg of niacin from niacin 99.5%. Trace mineral premix provided per kg of complete feed:165.3 g Zn from ZnO; 165.3 g Fe from FeSO ; 39.7 g Mn from MnO; 16.5 g Cu from CuSO ; 0.30 mg I from CaI O ; and 0.30 mg Se from NaSeO . 4 2 6 4 after the start of experiment (day 49), approximately HEAVY vs. LIGHT treatments, and their inter- 3 wk before the conclusion (day 81), and at the con- action with dietary fat addition. clusion of the experiment (day 95). Similar to the first experiment, the two heaviest pigs from HEAVY pens RESULTS and the heaviest pig from MIXED pens were visually selected and removed at the third weigh period. At Experiment 1 the end of the experiment, pigs from each pen were The addition of fat to diets increased (P < 0.05) individually tattooed and shipped to the same pro- ADG from day 0 to 56 (0.72 vs. 0.70 kg/d) and from cessing plant where the standard carcass criteria were day 56 to 88 (0.86 vs. 0.83 kg/d; Table 2). From day measured as in experiment 1. 88 to 109 and during the overall study, there was a HEAVY vs. LIGHT × fat interaction (P < 0.05) for ADG. This occurred because ADG increased when Statistical Analysis fat was added to diets for LIGHT pigs, but not when Data from both experiments were analyzed as fat was added to diets for HEAVY pigs. Adding fat a completely randomized design with pen as the to the diet reduced (P  <  0.01) average daily feed experimental unit. Analysis of variance was per- intake (ADFI) and increased (P  <  0.01) gain:feed formed using the MIXED procedure of SAS (SAS ratio (G:F) during each period. A  HEAVY vs. Institute, Inc., Cary, NC). Single degree-of-freedom LIGHT × fat interaction (P < 0.05) for ADFI was contrasts were used to determine the main effects observed from day 88 to 109 and the overall study. of dietary fat addition and sort weight category as This appeared to be the result of a greater reduc- well as their interaction on growth performance. tion in ADFI for HEAVY vs. LIGHT pigs when fat Preplanned nonorthogonal contrasts were also was added (P < 0.01). used to compare the sorted (HEAVY and LIGHT The addition of fat to diets increased (P = 0.03) pens combined) vs. unsorted (MIXED) treatments, day 88 BW (99.4 vs. 97.6 kg) but had no effect on Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 4 Chad et al. Table 2. Effects of added fat and initial sort on growth performance of finishing pigs (experiment 1) 0% 6% Main effect P-value Interaction P-value Added dietary fat: HEAVY HEAVY vs. Sorted vs. vs. Sorted vs. LIGHT MIXED Sort category: HEAVY LIGHT MIXED HEAVY LIGHT MIXED SEM Fat LIGHT MIXED by fat by fat Average daily gain, kg day 0 to 56 0.75 0.64 0.70 0.77 0.69 0.71 0.014 0.04 0.01 0.42 0.27 0.45 day 56 to 88 0.85 0.82 0.82 0.87 0.84 0.85 0.012 0.02 0.06 0.50 1.00 0.68 day 88 to 109 1.07 0.98 1.00 1.00 1.00 1.01 0.021 0.35 0.10 0.65 0.04 0.28 Overall 0.84 0.77 0.80 0.83 0.80 0.81 0.009 0.08 0.01 0.51 0.03 0.66 Average daily feed intake, kg day 0 to 56 1.83 1.47 1.64 1.69 1.43 1.52 0.032 0.01 0.01 0.33 0.10 0.73 day 56 to 88 2.64 2.30 2.44 2.37 2.17 2.24 0.039 0.01 0.01 0.37 0.11 0.99 day 88 to 109 3.02 2.67 2.77 2.60 2.44 2.56 0.044 0.01 0.01 0.63 0.03 0.13 Overall 2.26 1.93 2.06 2.03 1.82 1.91 0.031 0.01 0.01 0.41 0.05 0.76 Gain:feed ratio day 0 to 56 0.41 0.43 0.42 0.45 0.48 0.46 0.006 0.01 0.01 0.56 0.76 0.79 day 56 to 88 0.32 0.35 0.34 0.36 0.38 0.38 0.006 0.01 0.01 0.22 0.12 0.12 day 88 to 109 0.36 0.37 0.36 0.38 0.41 0.39 0.007 0.01 0.02 0.99 0.25 0.99 Overall 0.36 0.39 0.38 0.41 0.43 0.42 0.004 0.01 0.01 0.89 0.90 0.45 A total of 1,032 gilts (24 or 25 pigs per pen and 7 pens per treatment) with an initial average weight of 30.7 kg. Pigs were sorted based on body weight at placement. HEAVY, pig from the heaviest 50% of the population; LIGHT, pig from the lightest 50% of the population; MIXED, pigs from the whole population with normal distribution around body weight mean. Mean of combined HEAVY and LIGHT treatment groups. final BW (119.2 vs. 118.0 kg), CV of individual BW (P < 0.01) ADFI but increased (P < 0.01) G:F dur- (11.8 vs. 11.0%), or CV of ADG (14.1 vs. 13.3%; ing each period. Table 3). There was no evidence for difference (P > Pigs from the HEAVY category had increased 0.42) among pigs fed diets with or without added (P < 0.05) ADG and ADFI, but decreased (P < 0.01) fat on back fat, fat-free lean index, percent lean, or G:F, compared with the LIGHT category during loin depth. each growth period, except for ADG from day 49 For the effects of BW sorting, HEAVY pigs had to 81 and G:F from day 81 to 95. However, when greater BW compared with LIGHT pigs during each combining the HEAVY and LIGHT treatment period, but when combined, the average weight of groups, pigs from the SORTED pens had similar sorted pigs (HEAVY and LIGHT) was similar (P > ADG, ADFI, and G:F compared with MIXED (P 0.40) to the MIXED pigs. There was a HEAVY vs. > 0.25). LIGHT × fat interaction (P  =  0.05) for final BW, Adding dietary fat increased (P  <  0.01) BW which occurred because BW was increased when fat at the end of each period (Table 5). However, was added to diets for LIGHT pigs, but not when adding fat had no effect (P > 0.41) on CV of BW fat was added to diets for HEAVY pigs. Pigs sorted in any period. Feeding pigs diets with fat reduced into HEAVY pens maintained lower (P = 0.05) BW (P < 0.01) CV of ADG from day 49 to 81 (15.3 vs. CV compared with that of LIGHT pens throughout 12.6%); however, this response was not observed (P the study. Furthermore, sorted pigs had decreased > 0.64) in other periods. (P < 0.10) BW CV throughout the study compared Pigs from the HEAVY category maintained with the MIXED pigs. However, sorting had no ef- greater (P  <  0.01) BW with lower (P  <  0.01) CV fect (P > 0.38) on CV of ADG or carcass traits. compared with those from the LIGHT category throughout the experiment. There was a HEAVY vs. LIGHT × fat interaction (P  <  0.10) for BW Experiment 2 CV on day 49 and 81. This seemed to be a mag- No sort category × fat interaction was ob- nitude effects because in diets without added fat, served for any growth responses (P > 0.26). Pigs fed BW CV was greater in LIGHT pigs than HEAVY, diets with added fat had greater (P  <  0.01) ADG but adding fat to diets had only a modest in- from day 0 to 49 and for the overall experimental crease in BW CV among HEAVY and LIGHT period (Table 4). Adding fat to the diets decreased pigs. When combining the HEAVY and LIGHT Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 Adding fat to diets of pigs sorted by weight 5 Table 3. Effects of added fat and initial sort on weight variation, carcass traits in finishing pigs (experiment 1) Added dietary fat: 0% 6% Main effect P-value Interaction P-value HEAVY vs. Sorted vs. HEAVY vs. Sorted vs. LIGHT MIXED Sort category: HEAVY LIGHT MIXED HEAVY LIGHT MIXED SEM Fat LIGHT MIXED by fat by fat Pig weight, kg day 0 34.68 26.79 30.80 34.72 26.79 30.63 0.330 0.88 0.01 0.91 0.95 0.75 day 56 77.62 63.52 70.80 78.38 66.17 71.06 0.930 0.11 0.01 0.55 0.32 0.38 day 88 105.42 89.96 97.41 106.49 93.10 98.60 1.009 0.03 0.01 0.40 0.31 0.60 day 109 125.63 110.90 117.42 124.43 114.08 119.19 1.079 0.17 0.01 0.63 0.05 0.68 Pig weight, CV day 0 8.72 11.02 15.87 8.72 12.67 15.42 0.706 0.49 0.01 0.01 0.25 0.30 day 56 11.55 15.69 15.05 12.76 14.72 16.20 1.257 0.65 0.02 0.08 0.39 0.64 day 88 9.07 13.34 13.25 11.38 12.77 14.08 0.997 0.30 0.01 0.02 0.16 0.98 day 109 8.38 12.18 12.40 9.98 12.79 12.59 0.933 0.30 0.01 0.05 0.60 0.58 Average daily gain, CV day 0 to 56 18.61 23.68 20.09 19.75 20.35 21.23 2.184 0.85 0.44 0.97 0.31 0.56 day 56 to 88 14.52 14.41 17.35 15.21 17.11 17.33 1.312 0.30 0.18 0.08 0.45 0.45 day 88 to 109 19.06 17.74 22.47 18.99 21.75 18.60 2.526 0.99 0.84 0.60 0.42 0.19 Overall 10.83 14.54 14.48 12.89 15.18 14.14 1.236 0.44 0.05 0.38 0.57 0.43 Carcass traits Back fat, mm 14.99 14.15 14.44 15.02 14.41 14.59 0.013 0.59 0.10 0.66 0.75 1.00 Fat-free lean 51.63 51.30 51.53 51.53 51.35 51.58 0.153 0.98 0.20 0.46 0.63 0.80 index, % Lean, % 56.95 57.56 57.14 57.02 57.16 57.48 0.290 0.99 0.38 0.58 0.43 0.32 Loin depth, cm 6.02 6.11 5.90 6.11 5.91 6.27 0.134 0.42 0.85 0.70 0.30 0.07 A total of 1,032 gilts (24 or 25 pigs per pen and 7 pens per treatment) with an initial average weight of 30.7 kg. Pigs were sorted based on body weight at placement. HEAVY, pig from the heaviest 50% of the population; LIGHT, pig from the lightest 50% of the population; MIXED, pigs from the whole population with normal distribution around body weight mean. Mean of combined HEAVY and LIGHT treatment groups. Coefficient of variation. Values derived from processing plant. treatment groups, sorted pigs had similar BW, but et  al., 2018). Variation in growth is the result of decreased (P  <  0.01) CV of BW, compared with differences in health, genetic makeup, and social MIXED pigs throughout the study. A HEAVY vs. interactions. Days to market for a group of pigs is LIGHT × fat interaction (P = 0.03) was observed dictated by the growth rate of the lightest 50% of for CV of ADG from day 0 to 49. This response the pigs in the barn because they must reach a min- occurred because CV of ADG increased when fat imum weight to reduce sort discount by the pro- fed to HEAVY pigs, while adding fat to diets for cessor. Thus, within a population of pigs, increasing LIGHT pigs decreased CV of ADG. The influence the ADG has more value in lightweight pigs than of sorting on CV of ADG was inconsistent with their heavy weight counter parts. a response observed from day 0 to 49 and day 81 Energy is important because it is the most ex- to 95 (P < 0.05), but not from day 49 to 81 or the pensive component of the diet, and it has a signifi- overall trial. cant impact on animal performance and nutrient utilization. Increasing dietary energy, such as with addition of dietary fat, is one of the few nu- DISCUSSION tritional tools available to increase ADG for pigs Lightweight pigs are a costly problem in all-in, fed an otherwise nutritionally adequate diet. In all-out swine production. Variation in growth is commercial swine production, dietary energy level costly because it increases the penalty for sort loss, often limits ADG (De la Llata et al., 2001b). Many increases the number of days to bring lightweight studies have shown that the addition of dietary fat pigs to market weights, and results in extra facility to corn-soybean meal-based diets increases ADG cost (van Barneveld and Hewitt, 2016; López-Vergé and G:F (Benz et  al., 2011; Kellner et  al., 2014; Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 6 Chad et al. Table 4. Effects of added fat and initial sort on growth performance of finishing pigs (experiment 2) Added dietary fat: 0% 6% Main effect P-value Interaction P-value HEAVY HEAVY vs. Sorted vs. vs. Sorted vs. LIGHT MIXED Sort category: HEAVY LIGHT MIXED HEAVY LIGHT MIXED SEM Fat LIGHT MIXED by fat by fat Average daily gain, kg day 0 to 49 0.83 0.79 0.81 0.86 0.83 0.85 0.010 0.01 0.01 0.89 0.40 0.81 day 49 to 81 0.94 0.93 0.93 0.95 0.96 0.95 0.058 0.16 0.96 0.80 0.77 0.83 day 81 to 95 1.02 0. 90 0.95 1.05 0.93 0.97 0.045 0.43 0.04 0.75 0.99 0.88 Overall 0.88 0.85 0.87 0.91 0.89 0.90 0.008 0.01 0.02 0.91 0.37 0.89 Average daily feed intake, kg day 0 to 49 2.12 1.93 2.03 1.98 1.80 1.90 0.025 0.01 0.01 0.83 0.84 0.99 day 49 to 81 2.64 2.49 2.57 2.45 2.28 2.36 0.032 0.01 0.01 0.94 0.82 0.84 day 81 to 95 3.07 2.83 2.99 2.89 2.57 2.68 0.048 0.01 0.01 0.99 0.40 0.26 Overall 2.70 2.28 2.46 2.51 2.09 2.27 0.025 0.01 0.01 0.25 0.91 0.97 Gain:feed ratio day 0 to 49 0.39 0.41 0.40 0.43 0.46 0.45 0.005 0.01 0.01 0.93 0.30 0.67 day 49 to 81 0.35 0.37 0.36 0.39 0.42 0.41 0.009 0.01 0.01 0.78 0.75 0.52 day 81 to 95 0.33 0.32 0.32 0.36 0.36 0.36 0.012 0.01 0.86 0.75 0.67 0.86 Overall 0.36 0.38 0.37 0.41 0.43 0.42 0.004 0.01 0.01 0.68 0.28 0.83 A total of 1,176 gilts (28 pigs per pen and 7 pens per treatment) with an initial average weight of 35.1 kg. Pigs were sorted based on body weight at placement. HEAVY, pig from the heaviest 50% of the population; LIGHT, pig from the lightest 50% of the population; MIXED, pigs from the whole population with normal distribution around body weight mean. Mean of combined HEAVY and LIGHT treatment groups. Table 5. Effects of added fat and initial sort on weight variation, carcass traits in finishing pigs (experiment 2) Added dietary fat: 0% 6% Main effect P-value Interaction P-value HEAVY Sorted HEAVY Sorted vs. vs. vs. vs. LIGHT MIXED Sort category: HEAVY LIGHT MIXED HEAVY LIGHT MIXED SEM Fat LIGHT MIXED by fat by fat Pig weight, kg day 0 37.75 32.52 35.28 37.62 32.56 35.09 0.543 0.83 0.01 0.87 0.87 0.88 day 49 78.30 71.09 74.80 79.63 73.33 76.60 0.722 0.01 0.01 0.86 0.53 0.99 day 81 108.30 100.93 104.64 110.04 104.00 107.00 0.752 0.01 0.01 1.00 0.38 0.97 day 95 121.24 113.58 117.49 123.04 117.00 119.89 0.876 0.01 0.01 0.97 0.36 0.89 Pig weight, CV day 0 9.33 12.56 15.85 9.99 12.08 15.88 0.751 0.91 0.01 0.01 0.46 0.96 day 49 8.18 11.87 13.12 9.30 10.37 12.92 0.691 0.73 0.01 0.01 0.06 1.00 day 81 8.02 10.39 11.05 8.69 8.69 10.95 0.551 0.41 0.01 0.01 0.04 0.66 day 95 7.23 9.78 9.78 7.47 8.67 9.65 0.479 0.41 0.01 0.01 0.17 0.71 Average daily gain, CV day 0 to 49 10.68 15.00 14.78 13.03 12.58 14.36 1.028 0.84 0.04 0.06 0.03 0.83 day 49 to 81 15.61 15.80 14.55 14.21 10.82 12.69 1.134 0.01 0.33 0.62 0.12 0.50 day 81 to 95 18.92 27.30 18.69 19.23 23.07 21.02 1.766 0.72 0.01 0.15 0.21 0.17 Overall 8.86 10.64 9.79 9.44 9.41 9.74 0.612 0.64 0.34 0.74 0.15 0.80 A total of 1,176 gilts (28 pigs per pen and 7 pens per treatment) with an initial average weight of 35.1 kg. Pigs were sorted based on body weight at placement. HEAVY, pig from the heaviest 50% of the population; LIGHT, pig from the lightest 50% of the population; MIXED, pigs from the whole population with normal distribution around body weight mean. Mean of combined HEAVY and LIGHT treatment groups. Coefficient of variation. Stephenson et  al., 2016). In general, for every 1% Llata et  al., 2001b), although the improvements added dietary fat in a corn-soybean meal based can be greater. Benz et  al. (2011) observed a 9% diet, ADG is expected to increase 1% and G:F improvement in ADG (0.97 vs. 0.89 kg) for pigs fed is expected to improve approximately 2% (De la 5% added fat and Kellner et  al. (2014) evaluated Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 Adding fat to diets of pigs sorted by weight 7 100% 90% MIXED (no fat addition) MIXED (with fat addition) 80% HEAVY (no fat) + LIGHT (with fat) 70% 60% 50% 40% 30% 20% 10% 0% 70 80 90 100110 120130 140150 Body weight, kg Figure 1. Cumulative sum graph showing percentage of population over BW range. Pigs were sorted based on BW at placement. HEAVY, pig from the heaviest 50% of the population; LIGHT, pig from the lightest 50% of the population; MIXED, pigs from the whole population with normal distribution around BW mean. The graph represents three scenarios: 1) no added fat fed to MIXED pigs, 2) added fat fed to MIXED pigs, or 3) added fat fed to LIGHT pigs but not for HEAVY pigs. the addition of 6% of different fat sources and either with or without added fat. Using individual found up to 20% greater ADG (1.12 vs. 0.93 kg/d). weights from these treatments in both studies, a cu- However, the environment and housing (individual mulative sum graph was created (Figure 1) to rep- vs. pen) must be considered when comparing re- resent the portion of the population that would be sults. Patience (2001) calculated that, reducing en- at or below a specific weight. As the graph illus- ergy intake by 1% resulted in a decrease in growth trates, adding fat to the diet for the mixed popu- rate of about 1.2%. They also calculated that for lation simply shifts the population to the right each 1% reduction in energy intake, market weights resulting in fewer pigs being lower than the desired would be lowered by approximately 1  kg. In our weight range for the packer. Unfortunately, this studies, adding 6% fat in diets for LIGHT pigs shift of the curve for the mixed population also re- increased ADG by 3.9% in experiment 1.  In con- sults in more pigs being heavier than the optimal trast, HEAVY pigs had a slight decrease in ADG weight range for the packer when fat is added to (0.83 vs. 0.84 kg/d) when fed diets with added fat. the diet. If pigs would be sorted at the beginning This was unexpected and prompted us to conduct of the finisher with the lightest 50% of pigs fed the second study. In experiment 2, adding fat in higher energy diets and the heaviest 50% of pigs the diets increased ADG by 3.4% for HEAVY and fed lower energy diets, dietary fat could be fed to 4.7% for LIGHT pigs. Regardless, the magnitude only the lightweight population that needed the of the response for increasing ADG by adding fat extra weight gain. This situation is simulated in the was greater for LIGHT pigs than HEAVY pigs in combined group in Figure 1. Using this approach, both experiments. the lower end of the curve is shifted to the right The increase in weight in light pigs from adding because adding dietary fat increased ADG for the dietary fat moved a larger number of lightweight lightweight pigs. The upper end of the curve is not pigs closer and into the packers marketing window. shifted to the right because the heavy pigs would be For pigs heavier than the population mean, pro- fed the lower energy diet without added fat. This il- viding additional energy will increase market lustrates that an initial sorting in conjunction with weight and move a larger portion of pigs out of feeding two different dietary energy treatments the optimal weight range for the packer and in- may be effective in moving a higher percentage of crease sort discounts. A secondary analysis of our the pigs into the packer’s ideal marketing grid. In data was performed to evaluate the implications addition, it is important to note that the economics of feeding the lightest 50% of the population diets of adding fat to finishing diets depend on the de- with added fat while feeding diets without added sign of the production system as well as the prices fat to the heaviest 50% of the population. This of corn, soybean meal, fat, and carcass price. For population (combined) was then compared with instance, the value of the additional weight will the unsorted mixed populations that were fed diets depend on the availability of finishing space. If Translate basic science to industry innovation Percent of thepopulation, % Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 8 Chad et al. extra space already exists, the increase in ADG is improve growth performance. Sorting decreased worth only fewer days in the facility. When space BW variation, but not ADG variation, within a is limited, increasing the ADG is worth the extra population. weight sold at market (De la Llata et al., 2001a). Conflict of interest statement. None declared. Many producers try to minimize variation and discounts by sorting pigs into more uniform weight LITERATURE CITED groups at placement into the finishing barn. Several van Barneveld, R. J. and R. J. E. Hewitt. 2016. Reducing vari- studies (Brumm et  al. 2002; Wolter et  al., 2002; ation in pork production systems through maternal and Cámara et al., 2016) have reported that sorting pigs pre- and post-weaning nutrition strategies. Anim. Prod. Sci. 56:1248–1253. https://doi.org/10.1071/AN15396 into uniform weight pens did not improve overall Benz,  J.  M., M.  D.  Tokach, S.  S.  Dritz, J.  L.  Nelssen, performance. The present study was designed to J.  M.  DeRouchey, R.  C.  Sulabo, and R.  D.  Goodband. simulate the field scenarios where feeder pigs were 2011. Effects of increasing choice white grease in corn- sorted into two weight categories (HEAVY vs. and sorghum-based diets on growth performance, carcass LIGHT). In addition to the comparison between characteristics, and fat quality characteristics of finishing HEAVY vs. LIGHT categories, contrasts were also pigs. J. Anim. Sci. 89:773–782. doi:10.2527/jas.2010–3033 Brumm,  M.  C., and P.  S.  Miller. 1996. Response of pigs to performed to compare the combination of HEAVY space allocation and diets varying in nutrient density. J. and LIGHT treatment groups (referred as “sorted”) Anim. Sci. 74:2730–2737. doi:10.2527/1996.74112730x to MIXED (unsorted) pigs. This was done to de- Brumm,  M.  C., M.  Ellis, L.  J.  Johnston, D.  W.  Rozeboom, termine whether the sorting practice improved pig and D.  R.  Zimmerman; NCR-89 Committee on Swine performance. Results from both experiments sug- Management. 2002. Effect of removal and remixing of lightweight pigs on performance to slaughter weights. J. gested that even though heavier pigs maintained Anim. Sci. 80:1166–1172. doi:10.2527/2002.8051166x greater ADG than lighter pigs, the combination of Cámara, L., J. D. Berrocoso, A. Fuentetaja, C. J. López-Bote, sorted pigs had the same ADG, ADFI, and G:F C.  de  Blas, and G.  G.  Mateos. 2016. Regrouping of pigs as that of unsorted pigs. In experiment 2, there by body weight at weaning does not affect growth per- was an inconsistent response of sorting on CV of formance, carcass quality or uniformity at slaughter of ADG. This effect of sorting was not observed in heavy weight pigs. Anim. Sci. J. 87:134–142. doi:10.1111/ asj.12404 experiment 1.  Magowan et  al. (2011) found lower De la Llata, M., S. S. Dritz, M. R. Langemeier, M. D. Tokach, BW CV at 10 and 15 wk of age for pigs in uniform R. D. Goodband, and J. L. Nelssen. 2001a. Economics of weight groups compared to mixed weight groups. increasing lysine:calorie ratio and adding dietary fat for Conversely, O’Connell et al. (2005) determined that grow-finishing pigs reared in a commercial environment. the formation of uniform groups at 4  wk of age J. Swine Healt. Prod. 5:215–223. De la Llata, M., S. S. Dritz, M. D. Tokach, R. D. Goodband, did not affect 21  wk of age BW CV. Brumm and J.  L.  Nelssen, and T.  M.  Loughin. 2001b. Effects of Miller (1996) also found an inconsistent influence dietary fat on growth performance and carcass char- of added dietary fat on CV of final weight with acteristics of growing-finishing pigs reared in a com- added fat having no influence on CV in one experi- mercial environment. J. Anim. Sci. 79:2643–2650. ment, but increasing CV in the second experiment. doi:10.2527/2001.79102643x Sorting pigs at or near time of marketing can re- Ice, A. D., A. L. Grant, L. K. Clark, T. R. Cline, M. E. Einstein, T.  G.  Martin, and M.  A.  Diekman. 1999. Health and duce sort discounts received from packers; however, growth performance of barrows reared in all-in/all-out or the remained pigs in the facility assume greater fa- continuous flow facilities with or without a chlortetracyc- cility cost and reduce profitability. Thus, it is critical line feed additive. Am. J. Vet. Res. 60:603–608. to increase ADG of lightweight pigs in conjunction Kellner, T. A., K. J. Prusa, and J. F. Patience. 2014. Impact of with sorting. dietary fat source and concentration and daily fatty acid intake on the composition of carcass fat and iodine value In summary, because adding fat to the diets sampled in three regions of the pork carcass. J. Anim. Sci. of lightweight pigs improved ADG in both ex- 92:5485–5495. doi:10.2527/jas.2014-7567 periments, dietary fat could be used selectively in López-Vergé,  S., J.  Gasa, M.  Farré, J.  Coma, J.  Bonet, and the barn to increase the weight of the lightest 50% D.  Solà-Oriol. 2018. Potential risk factors related to pig of the pigs. Moreover, feeding additional dietary body weight variability from birth to slaughter in com- fat did not affect the variation in BW or ADG. mercial conditions. Trans. Anim. Sci. 2:383–395. https:// doi.org/10.1093/tas/txy082 By increasing dietary fat fed to the light pigs and Losinger,  W.  C., E.  J.  Bush, M, A. Smith, and B.  A.  Corso. removing fat from diets of heavy pigs, producers 1999. Mortality of grower/finisher-only swine operations may be able to increase the percentage of pigs in the United States. Arq. Bras. Med. Vet. Zootec. 51:141– marketed within the packers’ ideal grid. These 147. doi:10.1590/S0102-09351999000200003 studies also show that sorting feeder pigs based Magowan, E., M. E. E. Ball, K. J. McCracken, V. E. Beattie, R. Bradford, M. J. Robinson, M. Scott, F. J. Gordon, and on initial BW when placing into finishers did not Translate basic science to industry innovation Downloaded from https://academic.oup.com/tas/article-abstract/4/1/txz162/5588263 by guest on 18 February 2020 Adding fat to diets of pigs sorted by weight 9 C.  S.  Mayne. 2011. Effect of dietary regime and group advances in pork production. Proceedings of the Banff structure on pig performance and the variation in weight Pork Seminar, Adv. Pork Product. 15:257–266. and growth rate from weaning to 20 weeks of age. Livest. Payne, H. G., B. P. Mullan, M. Trezona, and B. Frey. 1999. A Sci. 136:216–224. doi:10.1016/j.livsci.2010.09.013 review—variation in pig production and performance. In: Main,  R.  G., S.  S.  Dritz, M.  D.  Tokach, R.  D.  Goodband, P.D.  Cranwell, editor. 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Translational Animal ScienceOxford University Press

Published: Jan 1, 2020

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