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首页> 外文期刊>Advances in Animal Biosciences >Why synchronization programs are now referred to as fertility programs for dairy cows: anupdate
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Why synchronization programs are now referred to as fertility programs for dairy cows: anupdate

机译：为什么同步计划现在被称为乳制品奶牛的生育计划：Anupdate

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The decrease in fertility from nulliparous to primi- and multiparous dairy cattle continues to be a criticalproblem limiting profitability and sustainability of dairy farms. Reproductive performance of lactating dairy cows isdependent upon service rate (or estrus detection rate), fertility of the service sire, and maternal fertility. Service rate can becontrolled utilizing Ovsynch based technologies. The majority of dairy producers in the U.S. regulate time to 1st andsubsequent artificial inseminations (AI) with Ovsynch (Pursley et al., 1995) technologies. High fertility sires in the U.S.can be chosen utilizing the USDA-ARS sire conception rate summaries. Yet, maternal fertility, defined as the mother’sability to ovulate a competent oocyte and provide an oviductal and uterine environment capable of fertilization andcomplete embryonic and fetal development, continues to be the key limiting factor for profitable reproductive performancein lactating dairy cows. Conception rates of lactating cows are approximately 30% compared to 60% in virgin dairy heiferswhen inseminated following a detected estrus (Sartori et al., 2004). Increasing conception rates of lactating cows to that ofheifers would allow producers to employ the most profitable calving interval strategies for cows with different productionlevels to increase profit. Aspects of maternal fertility that are limiting to conception and embryonic/fetal development, andmethods whereby Ovsynch can be modified to enhance maternal fertility while continuing to control service rate, arebecoming well defined. Key phenotypic differences in nulliparous heifers and lactating cows that relate to their fertilitydifferences have been utilized to develop fertility programs. They are: circulating concentrations of 1) progesterone and 2)estradiol-17b during ovulatory follicle development, and 3) the cycling status at time of synchronization. A significantchange in circulating concentrations of steroid hormones takes place following the transition from heifer to lactating cow(Sartori et al., 2002). Concentrations of progesterone drop to nearly half the levels in lactating cows compared tonulliparous heifers (Sartori et al., 2004). This difference in P4 appears to influence follicle growth by prolonging the age ofthe ovulatory follicle via reduced negative feedback of progesterone on pulses of luteinizing hormone. Allowing more LHpulses to occur may drive the growth of a dominant follicle similarly, but likely not to the extreme, to a persistent follicle(Roche and Ireland, 1981) and cause a reduction in the fertility potential of the follicle. When the persistent DF is allowedto ovulate, fertility is decreased in comparison to younger ovulatory follicles (Mihm et al., 1994). The ovulatory follicle isgreater in diameter in lactating cows compared to heifers, but lactating cows only have about of the circulatingconcentrations of estradiol compared to heifers just prior to the LH surge. There is clearly a positive relationship incirculating levels of estradiol and fertility. Cows that are anovular at the start of a fertility program are less likely to becomepregnant compared to cycling cows. These three concepts will be discussed in this presentation. Further informationincluding calendars of the 1st AI fertility programs described in the presentation may be found atwww.dairycattlereproduction.com.
机译：从初始和多体乳制力养牛的肥力降低仍然是乳业农场的批判性和可持续性。哺乳乳制品奶牛的生殖性能依赖于服务率（或发情检测率），服务岩石的生育能力和产妇生育率。使用基于OVSynch的技术可以获得服务率。美国大多数乳制品生产商中的乳制品生产商用Ovsynch（Pursley等，1995）技术规范了第1次和持续的人工营养素（AI）。使用美国农业部遗传率概念摘要，选择美国高等肥力。然而，母体生育能力定义为排卵具有能干卵母细胞并提供能够受精的胚胎和胎儿发育能力和子宫环境，继续成为泌乳奶牛盈利奶牛的关键限制因素。哺乳奶牛的概念率约为30％，而在检测到的Estrus次数后，维珍乳制品大肠的60％（Sartori等，2004）。提高哺乳奶牛的概念率促使生产者将允许生产者使用不同的经济型奶牛采用最有利可图的奶牛间隔策略来增加利润。有限制概念和胚胎/胎儿发育的母体生育率的方面，以及ovsynch的方法可以被修改，以提高母体生育，同时继续控制服务率，从而定义良好。利用与其生育者有关的禁止大母牛和哺乳期母线的关键表型差异，以发展生育计划。它们是：循环浓度为1）孕酮和2）排卵卵泡发育期间的雌二醇-17b，3）在同步时的循环状态。在从小母牛到哺乳牛的转变后发生了类固醇激素的循环浓度的高度经验化（Sartori等，2002）。孕酮浓度降至乳腺奶牛的近一半水平，比较了色素的小母牛（Sartori等，2004）。 P4的这种差异似乎通过延长泪珠的低负反馈延长了泪珠的曲氏素脉冲的阴性反馈来影响卵泡生长。允许发生更多的LHPPRUSES可能会同样地驱动显性卵泡的生长，但可能不会到极端，持续卵泡（罗氏和爱尔兰，1981）并导致卵泡的生育潜力降低。当持久性DF被允许排卵时，与年轻排卵卵泡相比，生育率降低（MIHM等，1994）。与小母牛相比，哺乳母线直径的排卵卵泡股票代理，但哺乳期奶牛与在LH激增之前的小母牛相比，雌二醇的循环融合。显然存在促亚雌二醇和生育率水平的正相关关系。与骑自行车的奶牛相比，在生育方案开始时的牛在生育计划开始时的可能性较小。这三个概念将在本演示文稿中讨论。在演示中描述的第1 AI生育计划的进一步信息包括在演示中描述的日历可以找到ATWWW.DairycattLereProduction.com。

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