Embryo death in cattle: an update
Embryo death in cattle: an update
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DOI：
10.1071/rd11914
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发表时间：
2012-01-01
影响因子：
1.9
通讯作者：
Morris, D. G.
中科院分区：
文献类型：
--
作者：
Diskin, M. G.;Parr, M. H.;Morris, D. G.
对于小母牛、肉牛和中产奶牛，受精率一般在90%以上。在高产奶牛中，它可能较低，而且变化可能更大。胚胎损失的主要部分发生在配种后第 16 天之前，新的证据表明高产奶牛在第 8 天之前损失更大。晚期胚胎丢失会造成严重的经济损失，因为人们常常意识到为时已晚，无法再繁殖雌性。受精前后周期内黄体酮的全身浓度影响胚胎存活；浓度过高或过低已被证明与存活率呈负相关。当奶牛在产犊后 70 至 100 天进行授精时，产犊后 4 周内的能量平衡和干物质摄入量对于确定受孕率至关重要。必须制定更平衡的育种策略，更加重视生育力、采食量和能量。可以利用生育性状的遗传变异性；基因组技术不仅可以让科学家更好地了解受精和怀孕的基本生物过程，而且可以识别负责提高胚胎存活率的基因。将它们纳入育种目标将提高胚胎存活的遗传进展率。在生产者的控制下，有一系列易于采用的管理因素，可以直接提高胚胎存活率或改善胚胎存活率低的后果。纠正几个领域的微小缺陷可以对牛群繁殖性能产生重大的整体影响。
For heifers, beef and moderate-yielding dairy cows, fertilisation generally exceeds 90%. In high-producing dairy cows, it may be lower and possibly more variable. The major component of embryo loss occurs before Day 16 following breeding, with emerging evidence of greater losses before Day 8 in high-producing dairy cows. Late embryo loss causes serious economic losses because it is often recognised too late to rebreed females. Systemic concentrations of progesterone during the cycles both preceding and following insemination affect embryo survival; too-high or too-low a concentration has been shown to be negatively associated with survival rate. Energy balance and dry matter intake during the 4 weeks after calving are critically important in determining conception rate when cows are inseminated 70 to 100 days after calving. More balanced breeding strategies with greater emphasis on fertility, feed intake and energy must be developed. Genetic variability for fertility traits can be exploited; genomic technology will not only provide scientists with an improved understanding of the underlying biological processes involved in fertilisation and the establishment of pregnancy, but could identify genes responsible for improved embryo survival. Their incorporation into breeding objectives would increase the rate of genetic progress for embryo survival. There is a range of easily adoptable management factors, under producer control, that can either directly increase embryo survival or ameliorate the consequences of low embryo survival rates. The correction of minor deficits in several areas can have a substantial overall effect on herd reproductive performance.