Messias de Bragan ca M, Mounier A M, Prunier A
Institut National de la Recherche Agronomique, Station de Recherches Porcines, Saint Gilles, France.
J Anim Sci. 1998 Aug;76(8):2017-24. doi: 10.2527/1998.7682017x.
We evaluated the effects of high ambient temperature and feed restriction in primiparous lactating sows. Females were exposed to either a constant thermoneutral (20 degrees C) or hot environment (30 degrees C). Lactating sows at 30 degrees C were given free access to feed (30AL; n = 12), and sows at 20 degrees C were restricted according to the feed intake recorded at 30 degrees C (20RF; n = 6) or were given free access to feed (20AL; n = 6). Jugular vein catheters were surgically inserted at 100 +/- 1 d postcoitum. During lactation, 30AL sows exhibited higher rectal temperatures (P < .05) than 20AL and 20RF sows. Feed intake was reduced by 43% for 30AL compared with 20AL sows. Daily body weight loss was lower (P < .05) in the 30AL than in the 20RF group, and mean litter daily gain over the whole lactation was 18% lower in 30AL than in 20AL sows (P < .05) and was intermediate in 20RF females. Plasma concentrations of thyroid hormones (triiodothyronine [T3] and thyroxine [T4]) were lower at 30 degrees C than at 20 degrees C at d 4 postpartum and d 8 after weaning for T4 (P < .001) and at d 4 postpartum (P < .001) and at d 1 and d 8 after weaning for T3 (P < .01) but were not influenced by feed restriction at 20 degrees C. Mean concentrations of cortisol measured on d 4 and 19 postpartum and on d 1 after weaning were lower in the 30AL than in the 20AL group (P < .05), and neither was different from that in 20RF sows. Ambient temperature and feed intake had no influence on prolactin concentrations on d 19 postpartum and d 1 after weaning. In the 30AL group, concentrations of T3, cortisol, and prolactin measured at d 19 postpartum were positively correlated with the litter gain observed during the 2nd and 3rd wk of lactation (P < .05). The return to estrus was slightly delayed in 20RF compared with 20AL sows (P < .05) and was quite variable in the 30AL group. These results demonstrate that high ambient temperature has negative consequences on litter growth and return to estrus and induces plasma hormonal variations, that cannot be fully mimicked by feed restriction in primiparous sows.
我们评估了环境高温和限饲对初产泌乳母猪的影响。将母猪置于恒定的中性温度环境（20摄氏度）或炎热环境（30摄氏度）中。处于30摄氏度环境中的泌乳母猪可自由采食（30AL；n = 12），处于20摄氏度环境中的母猪根据30摄氏度时记录的采食量进行限饲（20RF；n = 6）或自由采食（20AL；n = 6）。在妊娠100±1天时通过手术插入颈静脉导管。在泌乳期间，30AL组母猪的直肠温度高于20AL组和20RF组母猪（P <.05）。与20AL组母猪相比，30AL组母猪的采食量减少了43%。30AL组母猪的每日体重损失低于20RF组（P <.05），整个泌乳期的平均窝日增重，30AL组比20AL组母猪低18%（P <.05），20RF组母猪的平均窝日增重处于中间水平。产后第4天以及断奶后第8天，30摄氏度环境下的母猪血浆甲状腺激素（三碘甲状腺原氨酸[T3]和甲状腺素[T4]）浓度低于20摄氏度环境下的母猪，T4在产后第4天（P <.001）以及断奶后第8天（P <.001），T3在产后第4天（P <.001）以及断奶后第1天和第8天（P <.01），但20摄氏度环境下的限饲对其没有影响。产后第4天、第19天以及断奶后第1天测得的皮质醇平均浓度，30AL组低于20AL组（P <.05），且与20RF组母猪的皮质醇浓度均无差异。环境温度和采食量对产后第19天和断奶后第1天的催乳素浓度没有影响。在30AL组中，产后第19天测得的T3、皮质醇和催乳素浓度与泌乳第2周和第3周观察到的窝增重呈正相关（P <.05）。与20AL组母猪相比，20RF组母猪的发情恢复略有延迟（P <.05），30AL组母猪的发情恢复情况差异较大。这些结果表明，环境高温对仔猪生长和发情恢复有负面影响，并导致血浆激素变化，而初产母猪的限饲不能完全模拟这种影响。
