Evaluation of Nutritional Strategies to Reduce Growth Rate of Pigs Beyond 200 lb Body Weight

Abstract

A total of 356 finishing pigs (DNA; 241 × 600; initially 196.3 ± 2.43 lb) were used in a 44-d growth trial to evaluate nutritional strategies to reduce growth rate of pigs beyond 200 lb body weight. A total of 3 diets were manufactured (control, Lys-deficient, and corn) and arranged into 4 nutritional strategies. In stage 1 (d 0 to 28), pens received one of two dietary treatments (control or Lys-deficient). Then on d 28, pens of pigs previously fed the control diet were separated into 2 groups, one fed the control diet and the other the corn diet. Pens of pigs previously fed the Lys-deficient diet were separated into 2 groups, one fed the Lys-deficient diet and the other the corn diet. The control diet contained 13.0% CP and 0.70% standardized ileal digestible (SID) Lys; the Lys-deficient diet contained 10.3% CP and 0.50% SID Lys; and the corn diet contained 8.1% CP and 0.18% SID Lys. There were 9 to 10 pigs per pen and 9 pens per treatment. Pens were assigned to 1 of the 4 nutritional strategies in a randomized complete block design with initial weight as a blocking factor. In stage one (d 0 to 28), pigs fed the Lys-deficient diet had decreased (P < 0.001) ADG, F/G, and d 28 BW compared to pigs fed the control diet. There was no evidence of difference in ADFI between control and Lys-deficient diet. In stage 2 (d 28 to 44), pigs fed the corn diet had decreased (P < 0.05) ADG and poorer (P < 0.05) F/G compared to pigs fed the control or Lys-deficient diets. Pigs fed the Lys-deficient diet in both stages had decreased (P < 0.05) ADG and poorer (P < 0.05) F/G compared to pigs fed the control diet in both stages. For the overall period (d 0 to 44), pigs fed the Lys-deficient diet (stage 1) then corn diet (stage 2) had decreased (P < 0.05) ADG and final BW, and poorer (P < 0.05) F/G compared to the three other treatments. There was no evidence of difference for ADG, F/G, and final BW between pigs fed the Lys-deficient diet in both stages and pigs fed the control diet (stage 1) then corn diet (stage 2). Pigs of these two treatments had decreased (P < 0.05) ADG, F/G, and final BW, compared to pigs fed the control diet in both stages. For