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Title:Hybrid rye may partially or fully replace corn in diets fed to growing or reproducing swine
Author(s):McGhee, Molly Lee
Director of Research:Stein, Hans H
Doctoral Committee Chair(s):Stein, Hans H
Doctoral Committee Member(s):Emmert, Jason L; Parsons, Carl M; Carr, Scott N
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):cereal grains
corn
growth performance
hybrid rye
pig
sow
Abstract:Eight experiments were conducted to test the hypothesis that hybrid rye may replace corn in diets for gestating and lactating sows, weanling and nursery pigs, and growing-finishing pigs without negatively impacting growth performance. In experiment 1, 45 sows per treatment were fed diets in which 0, 25, 50, or 75% of corn was replaced with hybrid rye in corn-soybean meal control diets formulated for gestation or lactation. Results indicated no differences in average daily feed intake (ADFI) or average daily gain (ADG) among treatments in gestation, but sows fed greater amounts of hybrid rye in lactation weaned heavier litters (quadratic, P < 0.05) with greater numbers of weaned offspring (quadratic, P < 0.05). Individual pig weights were not influenced by diet, but pre-weaning pig mortality tended to be reduced (quadratic, P < 0.10) from sows fed diets with hybrid rye. Based on the observation that sow gestation ADFI and ADG were not influenced by hybrid rye inclusion in the first experiment, experiment 2 was conducted to test the hypothesis that the metabolizable energy (ME) in hybrid rye is not different from corn when fed to gestating sows. Results indicated that the ME of hybrid rye was less (P < 0.05) than of corn, but the difference was less pronounced than values previously determined in growing pigs, likely due to greater fermentative capacity of sows. Experiments 3 and 4 were conducted to test the hypothesis that feed preference and growth performance of pigs will not differ when hybrid rye replaces portions of corn in nursery diets. In a two-way choice experiment, pigs preferred (P < 0.05) a corn-based diet 56.6% of the time and a diet in which 50% of corn was substituted with hybrid rye 43.4% of the time. In experiment 4, pigs were fed diets with up to 30, 40, and 100% replacement of corn with hybrid rye in phase 1 (day 1 to 7), phase 2 (day 7 to 21), and phase 3 (day 21 to 34) diets, respectively. Results indicated no differences in average body weight or ADG during the experiment, but ADFI increased (quadratic, P < 0.05) with greater inclusion of hybrid rye in the diet in phase 3 and for the overall period. Consequently, gain:feed (G:F) was reduced (quadratic, P < 0.05) in phase 3 and overall as well. The incidence of diarrhea was reduced (quadratic, P < 0.05) for pigs fed diets containing 6 or 9% hybrid rye in phase 1. As hybrid rye inclusion in the diets increased, neutrophils decreased and then increased (quadratic; day 21, P < 0.10; day 34, P < 0.05), and blood urea N increased (day 21, quadratic, P < 0.05; day 34, linear, P < 0.05). Because no negative effects on growth performance were observed in phases 1 and 2 of experiment 4, experiment 5 was conducted to test the hypothesis that greater quantities of hybrid rye may be included at the expense of corn in nursery diets without impacting growth performance. Indeed, replacing up to 60% of corn with hybrid rye in phase 1 and up to 90% in phase 2 did not result in diminished performance of weanling pigs. Average daily gain and ADFI increased (linear, P < 0.05) with greater inclusion of hybrid rye in the diet in phase 1, and in phase 3, when up to 100% of corn was replaced with hybrid rye, body weights and ADG of pigs did not differ among treatments. Pigs consumed more feed (quadratic, P < 0.05) in phase 3 and overall, and thus G:F was reduced (quadratic, P < 0.05). Differences (quadratic, P < 0.05) in concentrations of cytokines on day 35 indicate that pigs fed hybrid rye experienced a greater degree of inflammation, but no differences in fecal scores or incidence of diarrhea were observed, and more importantly, growth was not affected. Experiments 6 and 7 were conducted to test the hypothesis that feed preference and growth performance of pigs will not be different when corn is replaced with hybrid rye in diets for growing pigs. In the two-way choice experiment, pigs preferred (P < 0.05) the diet containing corn as the exclusive cereal grain 83.4% of the time versus the diet containing hybrid rye as the exclusive cereal grain. Pigs in experiment 7 had a tendency for reduced ADFI (linear, P < 0.05) as the replacement rate of hybrid rye in the diet increased (0, 33, 66, or 100%). Nevertheless, final body weight on day 27 of the experiment did not differ among treatments, nor did ADG or G:F, indicating hybrid rye was well-utilized by growing pigs. Experiment 8 was conducted to test the hypothesis that substituting hybrid rye in place of corn in diets for growing-finishing pigs would not influence growth performance or carcass traits of pigs. Within each of the 3 dietary phases, 0, 33, 66, or 100% of corn was replaced with hybrid rye. Results indicated that growth performance of pigs fed hybrid rye was suppressed in phase 1, as ADG and ADFI were less (linear, P < 0.05) and day 35 bodyweight tended to be reduced (linear, P < 0.05) for pigs fed greater amounts of hybrid rye. However, pigs compensated in later phases, resulting in no difference in body weights among treatments on days 70 or 97. A tendency for reduced (linear, P < 0.10) ADFI emerged in the late finisher phase, which also resulted in a tendency for reduced ADG in the final phase of the experiment. Overall, ADG, ADFI, and G:F were not different among treatments for the entirety of the experimental period (day 1 to 97). Most carcass traits, including hot carcass weight, carcass yield, 10th rib fat thickness, loin eye area, and fat-free lean percent, were not different among treatments, but loins of pigs fed hybrid rye had lighter visual color (linear, P < 0.05) and lighter backfat instrumental color (linear, P < 0.05). Pigs fed greater amounts of hybrid rye had heavier organs (linear, P < 0.05), including heart, kidney, liver, and empty gastrointestinal tracts, likely as a result of the need to handle greater total N and dietary fiber from hybrid rye compared with corn. In conclusion, hybrid rye may replace up to 75% of corn in diets for gestating and lactating sows without influencing performance, and lactation performance may be improved when 17 to 34% inclusion rate of hybrid rye is fed. Nursery pigs and growing pigs prefer diets based on corn to diets containing hybrid rye when given the choice. Hybrid rye may replace up to 60% of corn in diets in the first week after weaning, up to 90% of corn in week 2 and 3 post-weaning, and up to 100% of corn in weeks 4 and 5 post-weaning without impacting ADG. The average daily feed intake of growing pigs may be limited upon introduction to hybrid rye, but overall, the ingredient is well-utilized by growing and finishing pigs. Hybrid rye may replace up to 100% of the corn in diets for finishing pigs without influencing most carcass traits, although organ weights will be expected to be heavier for pigs fed greater inclusion of hybrid rye.
Issue Date:2021-04-21
Type:Thesis
URI:http://hdl.handle.net/2142/110487
Rights Information:Copyright 2021 Molly McGhee
Date Available in IDEALS:2021-09-17
Date Deposited:2021-05


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