POSTPARTUM ESTRUS AND INVOLUTION OF THE UTERUS IN AN EXPERIMENTAL HERD OF HOLSTEIN-FRIESIAN COWS
POSTPARTUM ESTRUS AND INVOLUTION OF THE UTERUS IN AN EXPERIMENTAL HERD OF HOLSTEIN-FRIESIAN COWS
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DOI：
10.3168/jds.s0022-0302(55)94940-7
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发表时间：
1955-01-01
影响因子：
3.5
通讯作者：
CASIDA, LE
中科院分区：
文献类型：
--
作者：
BUCH, NC;TYLER, WJ;CASIDA, LE
本文分别对252头和322头荷斯坦黑白花奶牛正常产犊进行了分娩至子宫复旧和分娩至初产间隔的研究。复旧期平均间隔47天，始热期平均间隔33天。经产母牛（42 d）和经产母牛（50 d）的退化间隔差异极显著，且季节间差异显著，夏秋两季最短。在夏季产犊的母牛往往比在其他季节产犊的母牛更早进入发情期，而在冬季产犊的母牛从分娩到第一次发情的间隔最长。对产后不同时间间隔结束时进入发情期的奶牛的数据进行了检查，以确定子宫退化的奶牛的比例。在间隔30天后发情的所有奶牛中，6%的奶牛子宫退化，44%的奶牛在45天时退化，75%的奶牛在60天时退化，87%的奶牛在75天时退化，96%的奶牛在90天时退化，99%的奶牛在105天时退化，大约100%的奶牛在120天时退化。在产次季节组中，第一次产热和子宫复旧的间隔之间存在轻微的相关性（r = 0.147; P = 0.05）。一项对71头异常产犊的研究表明，与正常产犊的奶牛相比，退化间隔稍长（5天）。该组中的经产母牛也比经产母牛更早地退化。
A study of the intervals from parturition to involution of the uterus and from parturition to first heat was made respectively on 252 and 322 normal calvings in a Holstein-Friesian herd. Average interval to involution was 47 days, and to first heat was 33 days. The difference in the involution interval between primiparous (42 days) and pluriparous (50 days) cows was highly significant, and significant differences were observed among seasons, being shortest in the summer and autumn. Cows calving during summer tended to come in heat earlier than those calving in the other seasons, whereas those calving during winter had the longest intervals from parturition to first heat. Examination was made of the data on cows that had come into heat by end of different intervals of time postpartum to determine the proportions of such cows whose uteri were involuted. Of all cows in heat after an interval of 30 days, 6% had their uteri involuted, 44% had them involuted at 45 days, 75% at 60 days, 87% at 75 days, 96% at 90 days, 99% at 105 days, and approximately 100% at 120 days. A slight association within the parity season groups (r = 0.147; P = 0.05) was found between intervals to first heat and to involution of the uterus. A study of 71 abnormal calvings indicated a little longer interval (5 days) to involution than for cows calving normally. The primiparous cows in this group also involuted earlier than pluriparous cows.