205 Dietary Strategies to Limit Average Daily Gain of Late Finishing Pigs

Abstract

A total of 2,164 pigs [DNA610 x DNA241; initially 100.7 ± 2.14 kg body weight (BW)] were used in a 54.1 ± 3.85-day study to determine dietary strategies to limit average daily gain (ADG) in late finishing pigs raised in a commercial environment. Mixed-sex pens (20.0 ± 0.85 pigs/pen) balanced by initial BW and gender ratio were randomly assigned to 1 of 4 dietary treatments fed ad libitum with 27 replications each: (1) Nutritionally replete corn soybean-meal control (CTRL), (2) Treatment 1 with 21% reduced lysine and other amino acids (AAR), (3) Corn/vitamin/mineral diet (CVM), and (4) Treatment 3 fed for 21 days then switched to CTRL. Data were analyzed as a randomized complete block design using a linear mixed model. Relative to CTRL, feeding AAR or CVM for 21 days reduced ADG (P < 0.001), average daily feed intake (ADFI; P = 0.005), and gain-to-feed (G:F, P < 0.001). Over 55-days, AAR and CVM diets reduced (P < 0.001) cumulative ADG, ADFI, G:F, and final BW compared to CTRL. Transitioning to CTRL diet from CVM diet after 21-days increased ADG (P < 0.001) and improved G:F (P < 0.001) from day 21 to marketing compared to 55-day CTRL, AAR, and CVM; nevertheless, the compensatory CTRL period was insufficient for the 21-day CVM fed pigs to fully compensate resulting in reduced cumulative BW, ADG (P < 0.001) and poorer G:F (P < 0.001) than the 55-day CTRL. All holding strategies decreased (P < 0.001) carcass yield, hot carcass weight (HCW), and loin depth compared to CTRL. Utilizing a CVM diet for 21 or 55 days increased (P < 0.001) backfat compared to CTRL or AAR. In summary, utilizing lysine deficient or corn/vitamin/mineral diets can limit ADG along with poorer G:F. Transitioning to a non-holding diet after feeding a corn/vitamin/mineral diet for 21-days resulted in compensatory gain, but reductions in growth performance and carcass traits remained evident.