Amino Acid Case Study - (Growth In Pigs)SUMMARY Lysine requirement of sows nursing large litters. A cooperative study. Knabe, D. A., L. I. Chiba, E. T. Kornegay, and J. C. McConnell, S-145 Committee on Nutritional Systems for Swine to Increase Reproductive Efficiency. A cooperative experiment was conducted at four stations (AL, SC, TX, and VA) to evaluate the lysine requirement of sows nursing large litters. Stations could begin with gilts or sows but all females remained on their treatments for three parities unless culled for failure to breed or structural unsoundness, or inadequate litter size. Pigs were transferred among litters to achieve minimum litter sizes of 9 or 10 pigs on day-3 of lactation for gilts and sows, respectively. During lactation, females had ad libitum access to diets formulated to contain 0.60, 0.75 or 0.90% lysine by altering the proportions of corn and soybean meal. All sows were fed 1.8 kg of the 0.60% lysine diet during gestation. Pigs were weaned at about 28 days of age. Data from 479 litters were collected. Dietary treatments did not affect litter size after transfer (10.8), litter size at 21 days (9.6), sow feed intake to day 21 (5.4 kg/day), or days to postweaning estrus (5.9 day). Increasing dietary lysine resulted in a linear decrease (P < 0.01) in sow weight loss from farrowing to day 21 of lactation (-6.3, -4.6, and -2.2 kg), but most of this response was due to gilts (-10.8, -9.8, and -4.9 kg; P < 0.01), not sows (-3.2, -3.0, -1.4 kg; P > 0.10). Average pig weights at 21 days were increased linearly (5.2, 5.4, and 5.5 kg/pig; P < 0.01) by increasing dietary lysine, but a treatment x station interaction (P < 0.05) occurred. At one station (n = 254) a linear increase was found, whereas there was no response to 0.90 % lysine at two stations (n = 186). At one station (n = 39), there was a response to 0.90% lysine but not to 0.75% lysine. Increasing dietary lysine in the first farrowing tended (linear, P = 0.07) to increase total (10.5, 10.8, and 11.2) and live (9.7, 9.9, and 10.2) pigs born/litter in subsequent farrowings. Overall, these data indicate that sows and gilts nursing large litters need at least 0.90% lysine for maximum reproductive performance. |
