J.C. Peters and D.C. Mahan1
The Ohio State University Department of Animal Sciences
Abstract
A study evaluated the effects of dietary lysine level, lysine source and dextrose on lactating sow and litter performance. Seventy-four sows, involving a total of 192 farrowings over 4 parities, were used in a 3 x 2 factorial experiment. The first factor evaluated three dietary lysine levels during lactation, while the second factor evaluated two dietary dextrose levels (0 or 10%). A basal level was formulated to meet the National Research Council (NRC) lysine requirement (0.90%) for both first-parity and multiparous sows. First-parity sows were fed the basal level, a diet with an additional 0.30% lysine from soybean meal (SBM), or a combination of 0.18% lysine from SBM and 0.12% synthetic lysine. During parities 2 through 4, the basal level contained 0.90% (total) lysine, but the 2nd and 3rd treatment groups were fortified with either 0.15% lysine from SBM or synthetic lysine. Lactation length was 21 days for first-parity sows and 17 days for multiparous sows. Sow body weight and backfat measurements were collected during lactation. Lysine level and source had no effect on sow body weight, backfat thickness, lactation feed intake, or litter performance at weaning. Plasma urea nitrogen (PUN) concentrations were lower when synthetic lysine was added to the diets (P < 0.01). Fat and protein composition of the colostrum and milk, return to estrus interval, and subsequent litter size (total and live) were not affected by dietary lysine level and lysine source fed during lactation. The addition of 10% dextrose to the lactation diet did not improve sow or litter performance, but there was a trend towards higher total lactation feed intake (P < 0.10). Litter performances, lactation feed intakes, and subsequent reproductive performances were not improved by feeding lysine levels above NRC recommendations to sows at this level of production. Higher producing sows may require dietary lysine levels greater than those used in our trial.