乏情奶牛日粮营养水平和血浆生殖激素的变化

Changes of Reproduction Hormones in Plasma and Dietary Nutrition Levels on Anestrous Dairy Cows

选取产后65～75天无发情表现的泌乳奶牛,经直检分为卵泡闭锁(Ⅰ)、卵巢囊肿(Ⅱ)、持久黄体(Ⅲ)和排卵延迟(Ⅳ)4组,每组10头奶牛。应用放射免疫测定法检测每头奶牛血浆FSH、LH、E2、P4的水平,同时分析该牛场此时期日粮中营养水平。结果表明:饲料中能量、蛋白质和磷的含量低于NRC(2001)水平。4个组奶牛血浆中的FSH含量均低于正常水平;Ⅰ组血浆中的E2含量低于同期正常水平;Ⅱ组血浆中的E2含量高于正常水平;Ⅲ组血浆中的E2含量低于正常水平,P4的含量高于正常水平;Ⅳ组血浆中的E2含量高于正常水平,P4和LH的含量低于正常水平。结论:日粮能量、蛋白和磷含量较低导致的泌乳奶牛生殖激素的紊乱是引起奶牛乏情的主要因素。

Lactation cow of 65-75d after caving without heat were randomly selected. All the cows were divided into four experiment groups by rectal examination： atretic follicle group（ Ⅰ ）, ovarian cyst group （Ⅱ）, persistent corpus luteum group （Ⅲ） and delayed ovulation （Ⅳ）, which has 10 cows in every group. FSH, LH, E2 and P4 of levels in each cows ＇ plasma were measured by radioimmunoassay（RIA）, meanwhile analyzed nutritional composition of diet in this cattle ranch. Results showed that content of energy, protein and phosphorous in feeds were lower than the common model of NRC （2001）. The level of FSH of plasma in the four groups were all lower than normal level; the content of E2 of plasma in group Ⅰ was lower than normal level in the same period, hut group Ⅱ was higher; the content of E2 in plasma was lower than normal level and P4 was higher than normal level in group Ⅲ; and the content of E2 of plasma in group Ⅳ was higher than normal level, however, the content P4 and LH were lower normal level. The Conclusion is that the main factor causing dairy anestrous is the disorder of lactating dairy cow＇s reproductive hormones causing by low level of energy, protein and phosphorus in the ration.