Effect of dietary methionine-to-lysine ration on lactation performance of first- and second-parity Yorkshire and Hampshire lean genotype sows
2002
Grandhi, R.R.
A total of 196 Yorkshire (Y) sows, 137 of first and 59 of second parity, and 97 Hampshire (H) sows, 55 of first and 42 of second parity, were used to determine the effect of increased dietary amino acids and two methionine-to-lysine ratios on sow lactation performance. The three treatment diets were: (1) a barley-wheat-soybean meal diet containing lysine at 0.43 g MJ(-1) DE with no supplemental amino acids, 2) the same as diet 1, except the lysine content was increased to 0.68 g MJ(-1) DE with supplemental threonine and methionine providing threonine and methionine to lysine ratios of 0.60 and 0.26, respectively, and 3) the same as diet 2, except with an increased methionine-to-lysine ratio of 0.30. All diets were fed as pellets, ad libitum in self-feeders, with free access to drinking water during a 28-d lactation period. Nursing piglets were given creep feed after 14 d of age. The average daily feed intake increased during lactation, and it was higher (P < 0.05) in the second than the first parity sows. Feeding diets 2 and 3 increased (P < 0.05) sow lactation weight and backfat gains, compared to diet 1 for both breeds. Feeding diet 3 increased (P < 0.05) the sow lactation weight and backfat gains and piglet weight gains in the second parity Y sows, but not H sows. Post-weaning sow weight loss and weaning to estrus interval were not different (P > 0.10) among the diets in both breeds. Feeding diets 2 and 3 decreased (P < 0.05) the serum urea nitrogen concentration in Y sows indicating less amino acid catabolism. The results indicated that a dietary methionine-to-lysine ratio higher than 0.27 was not beneficial in maximizing lactation performance of modern lean genotype sows.
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