Manipulation of processing technologies to enhance growth performance and (or) reduce production costs in pigs
Year: 2011
Type: dissertation
Abstract: Nine experiments were completed to evaluate the effects of feed manufacturing practices on milling characteristics of diets and growth performance and stomach morphology in pigs.In Exp. 1 and 2, reducing the particle size of sorghum from 800 to 400 μm improved (P < 0.04) efficiency of gain in finishing pigs by 5% but had negative effects on cost of milling and stomach morphology.In Exp. 3 and 4, finishing pigs fed diets with 10 mg/kg of ractopamine HCl, had improved (P < 0.05) ADG, G:F, HCW, dressing percentage, and percentage carcass x Dedication I dedicate my thesis to my family for everything they have done for me.This would not be possible without their love and support. Chapter 3 -Effects of mix time for diets with ractopamine when fed to finishing pigs AbstractTwo experiments were completed to determine the effects of mix uniformity for diets with ractopamine HCl when fed to finishing pigs.In Exp. 1, a total of 200 pigs (average BW of 90 kg) were used in a 33-d growth assay arranged in a randomized complete-block design with 5 pigs/pen and 8 pens/treatment.Treatments were a corn-soybean meal-based control diet mixed for 360 s and the mixed control diet with 10 mg/kg ractopamine added before additional mixing for 0, 30, 120, and 360 s.Thus, this experiment was designed to determine the effects of nutrient utilization from a thoroughly mixed diet with a potential non-uniform distribution of ractopamine.Pigs fed diets with ractopamine had greater (P < 0.01) ADG, G:F, final BW, HCW, dressing percentage, loin depth, and percentage carcass lean with lower (P < 0.005) backfat thickness.Increasing mix time from 0 to 360 s decreased CVs for Cr from 67 to 12%, but had no effect (P > 0.15) on the response to ractopamine for any growth or carcass measurement.In Exp. 2, a total of 160 pigs (average BW of 93 kg) were used in a 27-d growth assay arranged in a completely randomized design with 2 pigs/pen and 16 pens/treatment.Treatments were a corn-soybean meal-based control mixed for 360 s and control diets with 10 mg/kg ractopamine mixed for 0, 30, 120, and 360 s.Thus, this experiment was designed to determine the combined effects of potentially non-uniform distribution of both nutrients and ractopamine.The use of ractopamine increased (P <0.01) ADG, G:F, final BW, HCW, dressing percent, percentage lean, and loin depth.Increasing mix times from 0 to 360 s decreased CVs for salt from 51 to 12% with no effect (P > 0.11) on ADG, G:F, HCW, dressing percentage, backfat thickness, loin depth, or percentage carcass lean.In conclusion, increasing mix time of diets from 0 to 360 s did not affect the response of finishing pigs to ractopamine.However, pigs fed the complete pellet had lower (P < 0.03) loin depth than those fed corn and the pelleted supplement.In conclusion, adding ground or cracked corn to a pelleted supplement had negative effects on ADG and G:F for nursery pigs.Scores for stomach lesions were lowest for pigs fed diets containing cracked corn.However, pigs fed pellets had the greatest efficiency of gain with average scores for keratinization and ulcers being only 0.5 units greater than the mash control. Chapter 5 -Effects of abrupt changes between mash and pellet diets on growth performance in finishing pigs AbstractA total of 200 finishing pigs (average initial BW of 60 kg) were used in a 58-d growth assay to determine the effects of an abrupt change from mash to pellets and pellets to mash on growth performance and carcass measurements.The experiment was designed as a randomized complete block with 5 pigs/pen and 10 pens/treatment.Treatments were mash to mash, mash to pellets, pellets to mash, and pellets to pellets for Phases 1 and 2 of the experiment.For Phase 1 (d 0 to 36), pigs fed the pelleted diet had 4% greater ADG and 8% greater G:F (P < 0.02) compared to pigs fed mash.For Phase 2 (d 36 to 58) and overall (d 0 to 58), pigs fed the mash diet had worse (P < 0.02) G:F than pigs fed the pelleted treatments.Indeed, pigs fed pellets the entire experiment had ADG and G:F that were 5 and 8% better, respectively, than pigs fed mash the entire experiment.Pigs fed mash during Phase 1 then pellets during Phase 2 had an greater (P < 0.01) ADG and G:F for Phase 2 compared to pigs fed pellets then mash.However, the overall effect was for pigs fed pellets for either Phase 1 or 2, but not both, tended to have growth performance intermediate to those fed mash and pellets for the entire experiment.With hot carcass weight used as a covariate, no differences (P > 0.15) were observed in dressing percentage, fat thickness, loin depth, or percentage fat free lean index (FFLI).In conclusion, pigs fed pellets tended to have the greatest growth performance, pigs fed mash the worst, and pigs fed pellets for only part of the grow-finish phase fell in between.
Author: Paulk, Chad Bennett
Language: English
Subfield: Animal Science and Zoology
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W2279293360