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Title:Effects of body weight and research conditions on the productive energy content of corn germ meal fed to growing-finishing pigs
Author(s):Estrada Restrepo, Jorge E
Director of Research:Ellis, Michael
Doctoral Committee Chair(s):Ellis, Michael
Doctoral Committee Member(s):Easter, Robert; Stein, Hans H; Gaines, Aaron M
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
productive energy
corn germ meal
growing period
research conditions
Abstract:Four experiments were conducted to investigate the effect of corn germ meal (CGM) inclusion level on growth performance and carcass traits of pigs, and to determine the productive energy (PE) of CGM by correcting ME estimates for caloric efficiency relative to a control (reference diet). All four experiments used a RCBD. The first two experiments were conducted from weaning (~6.5 kg BW) to finishing (~130 kg BW) at a commercial facility with CGM inclusions that ranged from 0 (Control) to 40%. The corn-soybean meal-based control diet (0% CGM) was used as the reference diet to compare with the CGM diets to estimate PE. Caloric efficiency (calories consumed per unit of weight gain) was calculated for each treatment using the feed:gain ratio. The ME value of CGM used to formulate diets in the first experiment was 3,037 kcal/kg. In this study, increasing CGM level linearly increased feed:gain (P < 0.05); based on these results the estimate of productive ME for CGM was 2,604 kcal/kg. In the second study, CGM diets were formulated using the ME value from the first experiment. In this study, increasing CGM inclusion level linearly increased (P < 0.05) feed:gain. This resulted in an estimate productive ME of CGM of 2,462 kcal/kg. Also, increasing CGM inclusion level linearly decreased (P < 0.05) carcass yield in both experiments. These results suggest that including CGM in diets for growing-finishing pigs has a negative impact on feed efficiency, and carcass yield. In addition, there was considerable variation in estimates of the PE content of CGM derived from these two growth studies. Two subsequent studies (Experiments 1 and 2) were conducted to determine the effect of research conditions (Commercial site vs University site), and different body weight ranges on estimates of PE of CGM. The same treatments were used in the 2 experiments; Exp. 1 was carried out at a commercial site and Exp. 2 was carried out at a university research facility. Three dietary treatments were compared: Control (corn-soybean meal-based diet), 20% CGM-No Fat (4.8% lower ME compared to the Control diet), and 20% CGM+Fat (yellow grease added to provide the same ME level as the Control diet); and 4 Growing periods were used: Early-Growing (29 to 64 kg BW), Late-Growing (64 to 96 kg BW), Finishing (96 to 127 kg BW), or Growing-Finishing (29 to 127 kg BW). At the commercial site the CGM+Fat diet was only fed during the Growing-Finishing period. A total of 3,672 and 576 were used in Experiment 1 and 2, respectively, housed in groups of 34 and 4, respectively (mixed-sex pens of barrows and gilts). The ME value of CGM used to formulate diets was that obtained in the previous growth study (adjusted for chemical composition of CGM batch used in these experiments). The variation in growth performance and caloric efficiency was considerably greater for Exp. 2 than Exp. 1 as evidenced by the SEM which were, on average, 1.7 times higher, resulting in greater variation in PE estimates from Exp. 2 compared to Exp. 1. Estimates of the productive ME of CGM based on the CGM‒No Fat diets for the Early-Growing, Late-Growing, and Growing-Finishing periods were similar (P > 0.05) in both experiments but numerically very different in Exp. 2 (2,465, 2,568, and 2,439, respectively, for Exp.1, and 2,455, 1,829, and 1,924, respectively, for Exp. 2). For Exp. 1 (commercial conditions), adding fat to the CGM diet resulted in similar productive ME estimates for CGM compared to CGM‒No Fat diet when measured during the whole of the Growing-Finishing period. Under university conditions (Exp. 2), fat addition to the CGM diet resulted in variable PE estimates between growing periods, and numerically greater values than those obtained with the CGM-No Fat diets. The results of these experiments suggest that the PE of CGM should be determined under commercial research conditions due to the variable results obtained under university conditions. Also, estimating PE over a limited part of the growing period resulted in similar PE estimates to those obtained during the whole of the growing-finishing period.
Issue Date:2017-04-14
Rights Information:Copyright 2017 Jorge Estrada Restrepo
Date Available in IDEALS:2017-08-10
Date Deposited:2017-05

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