International Sheep Research and National Research Centre for Growth and Development, Massey University, Palmerston North, New Zealand.
J Anim Sci. 2013 Feb;91(2):676-84. doi: 10.2527/jas.2012-5752. Epub 2012 Dec 10.
Studies using sheep models indicate that the fetal mammary gland is sensitive to maternal nutrition during gestation; however, results have been inconsistent and do not identify critical feeding periods. This study aimed to clarify previous findings by partitioning the period of maternal nutritional manipulation into 2 stages: early and mid-to-late pregnancy. Sixty-six twin-born, twin-bearing ewes, born to dams that were fed either submaintenance, maintenance, or ad libitum during early pregnancy (d 21 to 50 of pregnancy; SmP21-50, MP21-50, or AdP21-50, respectively) and then either maintenance or ad libitum during mid-to-late pregnancy (d 50 to 140 of pregnancy; MP50-140 or AdP50-140, respectively) were milked once a week, starting from d 7 ± 1 postpartum, for 7 subsequent weeks to enable estimation of daily milk yield and composition. Their lambs were weighed weekly. Ewes born to dams fed MP21-50 tended to have greater accumulated milk (P = 0.10), fat (P = 0.07), and NE (P = 0.06) yields over 50 d compared with ewes born to dams fed SmP21-50 and AdP21-50. In contrast, ewes born to dams fed AdP50-140 tended to have greater accumulated milk (P = 0.10) and lactose (P = 0.09) yields compared with ewes born to dams fed MP50-140. Grandoffspring birth weights were unaffected by granddam nutrition during pregnancy. Ewes born to dams fed AdP21-50 weaned lighter lambs (P = 0.05) than ewes born to dams fed AmP21-50 and tended to wean lighter lambs (P = 0.07) than ewes born to dams fed MP21-50 whereas there were no differences between the weaning weights of lambs (P = 0.43) from ewes born to dams fed AdP50-140 and MP50-140. Maintenance nutrition of dams during early pregnancy appears to be associated with an improved lactation performance of ewe offspring. Higher levels of nutrition during mid-to-late pregnancy also appears to improve the first-lactation performance of ewe offspring. Interestingly, although grandoffspring birth weights were unaffected, weaning weight appears to be influenced by granddam early pregnancy nutrition in a manner discordant with the lactational performance of their dam. Results from this study indicate that dam nutrition during early pregnancy can influence the lactational performance of ewe offspring and the BW at weaning of their grandoffspring, which may ultimately affect farmer profits. This highlights the importance of nutritional management of breeding ewes during this period.
本研究旨在通过将母体营养干预时期划分为两个阶段，即妊娠早期和妊娠中晚期，来澄清先前的研究结果。66 只双胎妊娠、双胎产的母羊，其母羊在妊娠早期（妊娠第 21 至 50 天；分别为低维持、维持或自由采食组 SmP21-50、MP21-50 或 AdP21-50）和妊娠中晚期（妊娠第 50 至 140 天；分别为维持或自由采食组 MP50-140 或 AdP50-140）接受不同的饲养，然后从产后第 7 天开始每周挤奶一次，持续 7 周，以估计日奶产量和成分。他们的羔羊每周称重一次。与 SmP21-50 组母羊所生的羔羊相比，MP21-50 组母羊所生的羔羊在 50 天内累积产奶量（P = 0.10）、脂肪（P = 0.07）和 NE（P = 0.06）产量较高。相比之下，与 MP50-140 组母羊所生的羔羊相比，AdP50-140 组母羊所生的羔羊累积产奶量（P = 0.10）和乳糖（P = 0.09）产量较高。母体营养对 grandoffspring 的出生体重没有影响。与 AdP21-50 组母羊所生的羔羊相比，MP21-50 组母羊所生的羔羊断奶体重较轻（P = 0.05），且 AdP21-50 组母羊所生的羔羊断奶体重有较轻的趋势（P = 0.07），而 AdP50-140 组母羊所生的羔羊和 MP50-140 组母羊所生的羔羊的断奶体重没有差异（P = 0.43）。妊娠早期母羊的维持营养似乎与母羊后代泌乳性能的提高有关。妊娠中晚期较高的营养水平似乎也能提高母羊后代的初乳性能。有趣的是，尽管 grandoffspring 的出生体重不受影响，但断奶体重似乎受到母羊早期妊娠营养的影响，与母羊的泌乳性能不一致。本研究结果表明，母羊在妊娠早期的营养可以影响母羊后代的泌乳性能和 grandoffspring 的断奶体重，这可能最终影响农民的利润。这突出表明，在这一时期，对繁殖母羊进行营养管理非常重要。
