Effect of feeding various gestation and lactation dietary protein sequences on long-term reproductive performance in swine.

An experiment was conducted at two locations with 87 crossbred swine for three parities to evaluate reproductive performance as affected by three different dietary protein regimens. During each of three gestation/lactation periods, one sow group received a 14/15% protein diet sequence, respectively, while a second received an 8.5/20% diet regimen. A third group was fed an 8.5% protein corn diet the first 75 days of pregnancy, 14% until parturition and a 16% lactation diet. Corn and soybean meal diets were formulated with ratios adjusted to achieve the desired protein level. Sow weights and gains were influenced by gestation protein level with lower gains consistently resulting at each parity when the corn (8.5%) diet was fed throughout pregnancy. Farrowing percentage and the number of pigs born were not significantly affected by any of the dietary treatments. Lactation feed intakes were highest from the sow group fed the 14/15% sequence and similar for the other two treatments at each parity. All sow groups gained weight during lactation with the largest gains with the group fed the 8.5/20% protein sequence. There was a trend for larger pig birth weights with a higher proportion of heavier pigs from sows fed the 14/15% protein sequence. This weight differential was, however, attributed to initial colostral consumption before birth weights were obtained, since initial milk pro-