Prepartum and postpartum nutritional management to optimize fertility in high-yielding dairy cows in confined TMR systems
Prepartum and postpartum nutritional management to optimize fertility in high-yielding dairy cows in confined TMR systems
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DOI：
10.1017/s1751731114000731
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发表时间：
2014-05-01
期刊：
影响因子：
3.6
通讯作者：
Cardoso, F. C.
中科院分区：
文献类型：
--
作者：
Drackley, J. K.;Cardoso, F. C.
以分娩为中心的 6 至 8 周时期，称为过渡期或围产期，对于奶牛个体的福利和盈利能力至关重要。高产奶牛的繁殖力因过渡困难而受到影响。营养或非营养管理的缺陷会增加围产期代谢紊乱和传染病的风险，从而降低随后的生育能力。阻碍生育的一个主要因素是产后早期负能量平衡（NEB）的程度，这可能会抑制首次排卵的时间、恢复周期和卵母细胞质量。特别是，前 10 天到 2 周（健康问题发生最多的时间）内明显的 NEB 对于以后的繁殖效率至关重要。避免过度调养并防止奶牛在妊娠后期过度消耗相对于其需求的能量，可以提高产犊后的干物质摄入量 (DMI) 和减少 NEB。对我们小组先前研究的汇总统计分析表明，与允许奶牛过度消耗能量相比，通过将能量摄入控制在接近奶牛产犊前的需要量，可缩短怀孕天数（减少 10 天）。为了控制能量摄入，总混合日粮 (TMR) 中的可代谢蛋白质、矿物质和维生素必须保持良好平衡，同时限制 DM 消耗总量，并且奶牛必须均匀消耗 TMR，无需分类。产犊前后和产后维持血钙和瘤胃健康的饮食管理也很重要。可能存在进一步改善新鲜奶牛能量状况的机会。最近操纵葡萄糖生成与脂肪生成平衡以及组织必需脂肪酸含量的研究很有趣。成功适应泌乳的高产奶牛可以具有较高的繁殖效率，产犊前和产后过渡期的营养管理必须促进这种适应。
The 6 to 8-week period centered on parturition, known as the transition or periparturient period, is critical to welfare and profitability of individual cows. Fertility of high-producing cows is compromised by difficult transitions. Deficiencies in either nutritional or non-nutritional management increase risk for periparturient metabolic disorders and infectious diseases, which decrease subsequent fertility. A primary factor impeding fertility is the extent of negative energy balance (NEB) early postpartum, which may inhibit timing of first ovulation, return to cyclicity, and oocyte quality. In particular, pronounced NEB during the first 10 days to 2 weeks (the time of greatest occurrence of health problems) is critical for later reproductive efficiency. Avoiding over-conditioning and preventing cows from over-consuming energy relative to their requirements in late gestation result in higher dry matter intake (DMI) and less NEB after calving. A pooled statistical analysis of previous studies in our group showed that days to pregnancy are decreased (by 10 days) by controlling energy intake to near requirements of cows before calving compared with allowing cows to over-consume energy. To control energy intake, total mixed rations (TMR) must be well balanced for metabolizable protein, minerals and vitamins yet limit total DM consumed, and cows must uniformly consume the TMR without sorting. Dietary management to maintain blood calcium and rumen health around and after calving also are important. Opportunities may exist to further improve energy status in fresh cows. Recent research to manipulate the glucogenic to lipogenic balance and the essential fatty acid content of tissues are intriguing. High-producing cows that adapt successfully to lactation can have high reproductive efficiency, and nutritional management of the transition period both pre-and post-calving must facilitate that adaptation.