Effects of diet form and type on growth performance, carcass yield, and iodine value of finishing pigs1

Abstract

Two experiments were conducted to determine the effects of pelleting, diet type (fat and fiber level), and withdrawal of dietary fiber and fat before marketing on growth performance, carcass yield, and carcass fat iodine value (IV) of finishing pigs. Each experiment used 288 pigs (initially 49.6 and 48.5 kg BW, respectively) with 6 dietary treatments arranged as 2 × 3 factorials. In Exp. 1, main effects were diet form (meal vs. pellet) and diet regimen. Diet regimens were 1) a low-fiber, low-fat (corn-soybean meal) diet from d 0 to 81, 2) a high-fiber, high-fat (30% dried distillers grains with solubles [DDGS] and 19% wheat middlings [midds]) diet from d 0 to 64 followed by the low-fiber, low-fat diet from d 64 to 81 (fiber and fat withdrawal), and 3) the high-fiber, high-fat diet fed from d 0 to 81.

Effects of corn distillers dried grains with solubles in finishing diets on pig growth performance and carcass yield with two different marketing strategies

“…1 and 2, IV increased by approximately 2–3 units, which could become meaningful if pigs are marketed to processing facilities that have quality control standards for carcass fat IV. Nevertheless, this response in belly fat IV is consistent with other literature where increased DDGS withdrawal period prior to harvest decreased IV ( Benz et al, 2008 ; Asmus et al, 2014 ; Nemechek et al, 2015 ).…”

“… Coble et al (2017) fed 0% or 30% DDGS for 20 d prior to market and observed no final BW effects, but feeding DDGS decreased HCW and yield. This response is consistent with much of the literature evaluating removing DDGS from the diet before harvest ( Gaines et al, 2007a ; Nemechek et al, 2015 ). Though the impact of feeding DDGS on carcass yield is well understood, the suggested time to remove DDGS from diets to restore yield varies.…”

“…During the last 24 d, pigs who were switched to the lower NDF/high NE diet had increased ADG and G:F compared with those who continued to consume the high NDF/low NE diet ( Graham et al, 2014 ). Nemechek et al (2015) also allowed NE level to change in low and high NDF diets and observed increased G:F with the fiber withdrawal. These experiments demonstrate how a dietary switch from lower to higher energy diets may increase the growth rate and feed efficiency of finishing pigs.…”

“…Literature has demonstrated that DDGS and other high NDF ingredients can decrease carcass yield due to increased gut fill and intestinal weights ( Turlington, 1984 ; Linneen et al, 2008 ; Asmus et al, 2014 ). Further, pork fat quality may be negatively impacted as a result of the increased unsaturated fatty acid content of DDGS, which can lead to increased IV ( Benz et al, 2008 ; Graham et al, 2014 ; Nemechek et al, 2015 ). To avoid the economic ramifications that result from decreased carcass yield and fat quality, pigs can be switched from diets containing DDGS to CSBM diets before harvest.…”

“…Though the impact of feeding DDGS on carcass yield is well understood, the suggested time to remove DDGS from diets to restore yield varies. Nemechek et al (2015) reported that switching from high NDF to low NDF diets for 17-d improved carcass yield compared with no dietary withdrawal period but was still decreased compared with a lower NDF control regimen fed for longer than 17 d. Coble et al (2018) and Asmus et al (2014) estimated that 5–10 d withdrawal periods could recover yield, but Gaines et al (2007b) reported that 42 d was necessary to fully recover yield. Our current study suggests that the complete recovery period for yield is at least 35 d, but due to the linear nature of the response, the appropriate withdrawal time for full recovery may be longer.…”