0
The increased efficiency and productivity of the sow herd due to the genetic improvement may affect nutrient requirements in lactation to meet the optimum performance. In lactation, nutrients need to be supplied to support both sow maintenance and litter growth. With milk production representing about 75% of total nutrient requirements in lactation, it becomes increasingly important to meet the sow’s requirements through diet formulation as litter size increases. It has been recently reported a decrease in BW loss without affecting litter performance when lysine is increased from 0.67 to 1.00% in the diet of lactating gilts but, varying the results in sows depending on response criteria. In modern genetics with greater productivity levels, meet the requirements to reduce mobilization of body protein reserves and maximize litter growth, maintaining reproductive function in high producing multiparous sows need to be re-evaluated. Therefore, 710 sows (mixed parities) were used in a 21-d study to determine the effect of standardized ileal digestible (SID) lysine (Lys) intake during lactation on sow and litter performance and subsequent reproductive performance of primiparous and multiparous sows housed in a commercial production system. On d 112 of gestation, females were weighed and blocked by BW within expected farrowing date and parity (1 to 7) and randomly assigned to 1 of 4 dietary treatments within blocks. Dietary treatments were corn-soybean meal-based and consisted of increasing SID Lys (0.75, 0.90, 1.05, and 1.20%). The experimental treatments were formulated by increasing both crystalline Lys and soybean meal to maintain a similar soybean meal to crystalline Lys ratio. Other feed-grade amino acids (AA) were added as needed to maintain a similar ratio to Lys across treatments. All other nutrients met or exceeded the NRC requirement estimates. Dietary metabolizable energy was fixed across all dietary treatments.
Sow BW at weaning increased (quadratic, P = 0.046), and sow BW loss from post-farrow to weaning or d 112 to weaning decreased (quadratic, P ≤ 0.01) as SID Lys increased. Sow backfat loss increased (linear, P = 0.028) as SID Lys increased. Conversely, longissimus muscle depth loss decreased (linear, P = 0.002) as SID Lys increased. Percentage of females bred by d 7 after weaning increased (linear, P = 0.047) as SID Lys increased in primiparous sows, with no difference in multiparous sows. Litter weight at d 17 and litter gain from d 2 to 17 increased (quadratic, P = 0.01) as SID Lys was increased up to 1.05%, with no improvement thereafter. For subsequent litter characteristics, there were no differences in total born, percentage born alive, stillborn, or mummies.
It is concluded that the present results suggest that increasing dietary SID Lys can reduce sow protein loss in lactation and overall tissue mobilization. However, the optimal level of dietary SID Lys required by the lactating sow may vary based on response criteria and parity.
Gourley, K. M.; Woodworth, J. C.; DeRouchey, J. M.; Tokach, M. D.; Dritz, S. S.; Goodband, R. D.; Kitt, S. J.; and Stephenson, E. W. (2017). Effects of increasing dietary lysine on performance of lactating sows in commercial conditions. Kansas Agricultural Experiment Station Research Reports: Vol. 3: Iss. 7. https://doi.org/10.4148/2378-5977.7457
