Growth and carcass quality of offspring in response to porcine somatotropin (pST) treatment of sows during early pregnancy

Abstract

The effects of maternal treatment with porcine somatotropin (pST) during early gestation on offspring growth, carcass quality, and immunological characteristics were determined. Thirty-two sows received daily injections of either a placebo ( n=16) or 6 mg of pST ( n=16) from day 10 to 27 of gestation with gradual withdrawal until day 37. In neonatal piglets, a birth weight group (BWG) by treatment interaction ( P<0.01) revealed decreases in the 25% heavy and 50% middle weight groups and an increase in the 25% low weight group within litters. Similar interactions were observed for muscle tissue ( P=0.03) and, in opposite direction, for fat ( P=0.05) percentages. The average percentage of muscle tissue was reduced ( P=0.03) by pST treatment, whereas percentages of internal organs ( P=0.05) and skin ( P=0.04) were enhanced. The susceptibility of piglets to infections at 2 days after weaning (day 30 of age) was not altered by pST treatment. Carcasses of slaughter pigs (day 182 of age) from pST-treated sows tended to deposit less meat than controls ( P=0.10) and to exhibit the same BWG by treatment interaction found at birth ( P=0.08). Meat quality at slaughter was changed towards higher intramuscular fat content ( P=0.01) and drip loss ( P=0.01). The results suggest that pST treatment during early gestation results in more balanced litters, but, on average, is not of advantage for carcass quality.