Department of Animal Sciences, The Ohio State University, OARDC, 1680 Madison Ave., Wooster 44691, USA.
J Anim Sci. 2012 Dec;90(13):4962-74. doi: 10.2527/jas.2012-5098. Epub 2012 Sep 5.
Mature Angus-cross beef cows (n = 228) were used to evaluate effects of prepartum dietary energy source on postnatal growth and carcass composition of progeny in a 2-yr study. Starting at approximately 160 d of gestation, cows were fed diets consisting of 1 of 3 primary energy sources: grass hay (HY), corn (CN), or dried corn distillers grains with solubles (DG). The CN and DG diets were limit-fed to achieve similar energy intakes as cows fed HY. Following parturition, cows were fed a common diet and managed as a single group. Calves were weaned at an average of 185 ± 6 d of age and backgrounded for 28 d. A subset of progeny (n = 134) was individually fed a common finishing diet until slaughter, when each calf reached 1.2 ± 0.05 cm of backfat. A glucose tolerance test (GTT) was conducted in year 2 on 4 calves/treatment after 41 and 111 d on the finishing diet (DOF). Calf birth weights were greater (P = 0.002) in calves from cows fed CN and DG than calves from cows fed HY, and weaning BW (P = 0.08) was less for calves from cows fed HY vs. CN. Receiving BW, final BW, and HCW did not differ (P ≥ 0.16) among treatments. No difference (P ≥ 0.28) in ADG, morbidity, and mortality from birth to slaughter was observed among treatments. In response to a GTT, increased DOF resulted in greater (P ≤ 0.005) fasting insulin, faster glucose disappearance rate, and greater insulin:glucose area under the curve ratio. Glucose disappearance rate was greater (P = 0.01) in calves from cows fed CN than in calves from cows fed HY or DG. A greater initial insulin response (P = 0.005) was observed in calves from cows fed CN or DG than in calves from cows fed HY. Carcass traits used to measure yield grade did not differ (P ≥ 0.19) among treatments. Calves from dams fed CN had the lowest marbling score (P = 0.03) and intramuscular fat content (P = 0.07). These results indicate that prepartum maternal dietary energy source can alter fetal adipose tissue development and insulin sensitivity resulting in long-term effects on progeny's intramuscular fat deposition. Moreover, present findings suggest that increasing the number of days on a corn-based finishing diet increases insulin resistance in beef cattle.
本研究旨在评估产前饲粮能量来源对后代生长和胴体组成的影响，选用 228 头成熟安格斯杂交肉牛进行为期 2 年的试验。从妊娠约 160 天开始，牛被喂食由 3 种主要能量源中的 1 种组成的饲粮：干草（HY）、玉米（CN）或干燥玉米酒糟及其可溶物（DG）。CN 和 DG 饲粮被限量喂食以实现与喂食 HY 的牛相似的能量摄入量。分娩后，牛被喂食相同的饲粮并作为一个单一群体进行管理。犊牛平均在 185±6 日龄断奶，并育肥 28 天。一部分后代（n=134）被单独喂食相同的育肥饲粮，直到达到 1.2±0.05cm 背膘厚时屠宰。在第 2 年，对每个处理组的 4 头犊牛进行了葡萄糖耐量试验（GTT），分别在育肥 41 天和 111 天后进行。与 HY 组相比，来自 CN 和 DG 组的犊牛出生体重更高（P=0.002），HY 组的断奶体重（P=0.08）更低。接受体重、终体重和活重无差异（P≥0.16）。在 ADG、发病率和死亡率方面，各处理间无差异（P≥0.28）。出生至屠宰期间，对 GTT 的反应，随着育肥天数的增加，空腹胰岛素水平增加（P≤0.005），葡萄糖清除率加快，胰岛素：葡萄糖 AUC 比值增加。来自 CN 组的犊牛葡萄糖清除率高于 HY 组或 DG 组（P=0.01）。来自 CN 或 DG 组的犊牛初始胰岛素反应更高（P=0.005），而 HY 组则较低。用于衡量产肉等级的胴体性状在各处理间无差异（P≥0.19）。来自 CN 组的犊牛大理石花纹评分最低（P=0.03），肌内脂肪含量最低（P=0.07）。这些结果表明，产前母体饲粮能量源可以改变胎儿脂肪组织发育和胰岛素敏感性，从而对后代的肌肉内脂肪沉积产生长期影响。此外，本研究结果表明，增加玉米育肥天数会增加肉牛的胰岛素抵抗。
