【摘要】 人工诱导不孕奶牛产奶,增加经济收益,是值得研究的课题。近年来,许多畜牧兽医工作者对此进行了探讨。 从1982年6月至1984年11月,作者对72头奶牛按不同给药方案进行试验。结果表明,诱导有效率达95.8％。305天平均产奶量为2611.7公斤,是对照组的67.07％。泌乳期最高奶产量为5139.85公斤。泌乳的高峰月从自然的第2个泌乳月推迟至第4个泌乳月,之后的变化曲线比较平稳。泌乳开始时乳汁呈浆液状的“初乳”。第2次诱导泌乳的产奶量要比第1次高。雌激素与孕激素剂量之间的比例对诱导有效率及奶产量无显著差异。辅助药物对诱导泌乳有些作用,但主要是用于预防而注射多量雌激素而引起的并发症。青年母牛与经产母牛在诱导效果方面差异不显著,而季节对诱导效果有明显影响,这可能由于环境条件不同而引起的催乳素释放差异。 人工诱导乳汁所含营养与常奶相似。用放射免疫法测定乳中雌激素含量,开始泌乳12天后下降至正常水平。证明用激素诱导泌乳所产生的乳汁是正常的,完全可食用。 激素注射时间由Smith等人的采用激素连续注射7天,本试验缩短到4天,效果无明显差异。加强对乳房的按摩,有效地促进了乳腺的发育。 人工诱导泌乳经济效益明显,每头牛在305天内其产值平均达1227.50元。更多还原

【Abstract】 This paper studies injecting of 17 β-estradiol and progesterone .for 4-7 days initiating lactation in infertile heifers and cows, the experiment performed in Zhejiang.The animals were divided into four groups on the basis of hormones. Groups Ⅰ Ⅱ and Ⅲ were given 7 injections each containing 0.1 mg 17β -estradiol/kg ( or 0.1 mg Diaethylstilbostrolum ) and 0.1-0.2mg progesterong/ kg for 1-7 days group Ⅳ was given 4 injecting oestrogen-progesterone following reserpine, Dexamethasone or LH were injected.The results show that successful ratio was 95.8%. The average 305-day milk yield was 2611.7kg. The peak milk production period was occurred a hundred and twentieth day after lactations and the persistency of lactation was approximately normal. Highest daily yield recorded was 23.75kg. Neither amount nor ratio of 17 β-estradiol and progesterone or plus reserpine at hormones is critical in initiation of lactation. Milk yield between heifer and cows was not significant difference, but the seasons were significant difference to the artificial induction of lactation.Composition and oestrogen-content in milk by hormones induced lactation was nearly normal.更多还原