Bates R O, Kelpinski J, Hines B, Ricker D
Department of Animal Science, Michigan State University, East Lansing 48824-1225, USA.
J Anim Sci. 2000 Aug;78(8):2068-71. doi: 10.2527/2000.7882068x.
Sows from five commercial herds were weaned in the fall and winter and used to ascertain the potential application of hormonal therapy to stimulate subsequent litter size born. At weaning sows within parity (1, 2, and 3 through 6) and lactation length classification (early weaned, < or = 14 d; conventionally weaned, > 14 d) were randomly assigned to treatment. Treatments were injection with P.G. 600 (400 IU PMSG with 200 IU hCG) at weaning or no treatment. Sows were individually observed for estrus and mated following protocol for each herd. Breeding, culling, and farrowing data were collected. Treatment with P.G. 600 did not change subsequent rebreeding performance for sows at parity 1 or parities 3 through 6. However, conventionally weaned parity-2 sows treated with P.G. 600 were more likely (P < .05) to return to estrus than conventionally weaned controls (99.0 vs 93.6%, respectively). For parity-1 and parity-2 sows, treatment did not significantly change the likelihood for farrow percentage. However, the likelihood to farrow a litter was greater (P < .05) among P.G. 600-treated sows at parities 3 to 6 that were conventionally weaned (84.4 vs 71.3%, respectively). Subsequent litter birth weight for parity-1 sows treated with P.G. 600 was lower (P < .02) than for controls (15.6 vs 16.6 kg, respectively). Subsequent litter size at birth was not affected by treatment for parity-1 or parity-2 sows compared with controls. However, early-weaned sows at parities 3 through 6 treated with P.G. 600 had more (P < .06) total number born than controls (12.4 vs 10.6, respectively). Treatment with P.G. 600 improved reproductive function within specific parity and lactation length classification for sows weaned in the fall and winter.
从五个商业猪场选取母猪，在秋冬季节进行断奶，并用于确定激素疗法刺激后续产仔数的潜在应用。断奶时，根据胎次（1、2以及3至6胎）和泌乳期长度分类（早期断奶，≤14天；常规断奶，>14天）将母猪随机分配至各处理组。处理方式为断奶时注射P.G. 600（400国际单位孕马血清促性腺激素和200国际单位人绒毛膜促性腺激素）或不进行处理。对母猪进行个体发情观察，并按照各猪场的方案进行配种。收集配种、淘汰和产仔数据。P.G. 600处理对第1胎或第3至6胎母猪的后续繁殖性能没有影响。然而，与常规断奶对照组相比，P.G. 600处理的常规断奶第2胎母猪发情返情的可能性更高（P <.05）（分别为99.0%和93.6%）。对于第1胎和第2胎母猪，处理对产仔率没有显著影响。然而，常规断奶的第3至6胎经P.G. 600处理的母猪产仔的可能性更高（P <.05）（分别为84.4%和71.3%）。P.G. 600处理的第1胎母猪的后续仔猪出生体重低于对照组（P <.02）（分别为15.6千克和16.6千克）。与对照组相比，处理对第1胎或第2胎母猪的出生时产仔数没有影响。然而，第3至6胎经P.G. 600处理的早期断奶母猪的总产仔数比对照组更多（P <.06）（分别为12.4头和10.6头）。P.G. 600处理改善了秋冬季节断奶母猪在特定胎次和泌乳期长度分类下的繁殖功能。
