Recombinant porcine somatotropin for sows during late gestation and throughout lactation

Abstract

Two experiments were conducted to evaluate whether administration of recombinant porcine somatotropin (pST) to sows (Hampshire-Yorkshire) enhanced lactational performance. In Exp. 1, sows (n = 84) were fed a corn-soybean meal diet (17.8% CP), or a similar diet with 8% added fat, from d 108 of gestation to d 28 of lactation. Half of the sows fed each diet were injected with 6 mg/d of pST from d 108 of gestation to d 24 of lactation. Diets were fed at 2.27 kg/d from d 108 of gestation until farrowing and then were self-fed during lactation. By d 3 of lactation, litter size was standardized at 8 to 10 pigs per litter. Treating sows with pST resulted in a 10-fold increase (P less than .001) in serum somatotropin at 4 h postinjection. Serum glucose was increased (P less than .01) and serum triglycerides, creatinine, and urea N were decreased (P less than .01) by pST. During the summer, apparent heat stress occurred in pST-treated sows, resulting in 14 deaths. Most (10) of the deaths occurred just before, during, or shortly after farrowing. Fewer (P less than .08) deaths occurred when pST-treated sows were fed the diet with added fat. Sows treated with pST consumed less feed (P less than .10) and lost more backfat (P less than .10) during lactation than controls. Increasing the dietary fat did not prevent these changes. Weaning weights of pigs and milk yield of sows (estimated by deuterium oxide dilution) were not affected by pST treatment. In Exp. 2, sows (n = 42) were injected weekly with 0 or 70 mg of pST on d 3, 10, 17, and 24 of lactation. Litters were standardized by d 3 at 8 to 10 pigs, and sows were fed the same control (low fat) diet as in Exp. 1. Sows treated with pST consumed less feed and lost more weight and backfat during lactation than untreated sows. Litter size, average pig weaning weights, and milk yield were not influenced by pST treatment. These data indicate that a 6-mg daily injection of pST from 6 d prepartum to d 24 of lactation or a 70-mg weekly injection of pST from 3 d postpartum to d 24 of lactation does not increase milk production in lactating sows.

Obstetric and neonatal outcomes to recombinant porcine somatotropin administered in the last third of pregnancy to primiparous sows

“…However, weight gain was associated with back fat loss in the latter group. These changes were previously reported in other studies and may be explained by the repartitioning effect of rpST (energy from fat to muscle) observed in growingfinishing pigs and in ST-treated sows (Cromwell et al 1992, Rehfeldt et al 2001.…”

“…Previous studies evaluating rpST administration during pregnancy have observed a certain number of deaths in sows before and during parturition and lactation (Smith et al 1991, Cromwell et al 1992. The mortality seems to be dose-related, with death rates of 0, 6, 26 and 100% in sows injected with 0, 4, 8 and 16 mg rpST respectively (Smith et al 1991).…”

Mammary Specific Transgenic Over-expression of Insulin-like Growth Factor-I (IGF-I) Increases Pig Milk IGF-I and IGF Binding Proteins, with no Effect on Milk Composition or Yield

“…Likewise, bovine ST (bST) is a potent stimulator of milk production in cows (Etherton and Bauman, 1998), however, the effect of porcine ST (pST) on lactation performance in swine is equivocal. Most (Cromwell et al, 1992;Toner et al, 1996), but not all (Harkins et al, 1989) studies, have shown little effect of exogenous pST on milk production in swine. Inhibition of GH secretion by immuno-neutralization of GH releasing factor, reduced serum IGF-I concentrations by 50% and milk production on d21 of lactation by 32% in swine, however, milk composition and piglet weight at weaning were unaffected, leading the authors to conclude that pST facilitates, but is not essential for lactation in swine (Armstrong et al, 1994).…”

Efeito da adição do óleo de soja, óleo de linhaça, óleo de coco babaçu e sebo bovino nos parâmetros produtivos e reprodutivos de fêmeas suínas em lactação

“…Vários autores registraram valores para peso corporal antes do parto (AZAIN, 1993;CROMWELL, et. al., 1992;LI e HACKER, 1995;SCHOENHERR et.…”

“…Em contrapartida foram apresentados valores para as perdas de peso, referentes ao período lactacional, mais elevados do que os encontrados na literatura (BABINSZKY, et. al., 1992b;CROMWELL et. al.,1992;LI e HACKER, 1995;SCHOENHERR et.…”