Tegegne A, Entwistle K W, Mukasa-Mugerwa E
International Livestock Centre for Africa (ILCA), Addis Ababa, Ethiopia.
Trop Anim Health Prod. 1993 May;25(2):101-10. doi: 10.1007/BF02236516.
Plasma progesterone profiles were used to monitor post-partum reproductive activity in 12 Small East African zebu (Bos indicus) cows allocated to either supplementary or no supplementary feeding (control) with continuous or restricted (twice daily) suckling regimes. Intact bulls were used for breeding. Blood samples were collected 3 times a week for 33 weeks to determine plasma progesterone levels. Weekly blood samples were also used to determine blood metabolite concentrations. Plasma progesterone levels remained below 1 ng/ml in all cows until week 12 post-partum. Only 5 cows showed ovarian activity over the 33 week period. Cows that cycled expressed irregular and short-lived progesterone rises (> 1 ng/ml) lasting 8 to 12 days prior to establishment of normal patterns of progesterone secretion where progesterone levels ranged from 8 to 10 ng/ml in cows with normal cycles. Plasma total protein, albumin, globulin, blood urea nitrogen and glucose levels varied over time without consistent trends, and were not influenced by either supplementary feeding of suckling regimes, nor differed between cyclic and acyclic cows. It was concluded that extended post-partum anoestrus, conception failure and early embryonic mortality were responsible for lowered reproductive efficiency in zebu cows. Blood metabolite concentrations were not good indicators of nutritional status and were not related to post-partum ovarian activity.
利用血浆孕酮水平监测12头东非小型瘤牛（Bos indicus）产后的生殖活动，这些母牛被分配到补充或不补充饲料（对照）组，并采用持续或限制（每日两次）哺乳方式。选用未阉割的公牛进行配种。每周采集3次血样，持续33周，以测定血浆孕酮水平。每周的血样还用于测定血液代谢物浓度。所有母牛在产后12周内血浆孕酮水平均低于1 ng/ml。在33周期间，只有5头母牛表现出卵巢活动。出现发情周期的母牛在建立正常孕酮分泌模式之前，孕酮水平会出现不规则且短暂的升高（>1 ng/ml），持续8至12天，正常发情周期母牛的孕酮水平在8至10 ng/ml之间。血浆总蛋白、白蛋白、球蛋白、血尿素氮和葡萄糖水平随时间变化，无一致趋势，且不受补充饲料或哺乳方式的影响，发情周期和无发情周期的母牛之间也无差异。研究得出结论，产后长期乏情、受孕失败和早期胚胎死亡是瘤牛生殖效率低下的原因。血液代谢物浓度不是营养状况的良好指标，且与产后卵巢活动无关。
