Factors that influence litter size in swine: parity 3 through 7 females.
Factors that influence litter size in swine: parity 3 through 7 females.
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影响猪产仔数的因素：胎次 3 至 7 只母猪。
DOI：
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发表时间：
1987
影响因子：
1.9
通讯作者：
Leman Ad
中科院分区：
文献类型：
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作者：
Clarke Lk;Leman Ad
研究了7个因素对第3 ~ 7胎次产仔数的影响（第一胎胎龄、第1胎次产仔数、前胎次泌乳持续时间、前胎次断奶至受胎间隔、前胎次产仔至受胎间隔、每次受胎交配次数和受胎月份），这些因素来自5个商业畜群的11,929胎次。在任何畜群中，第一胎胎的受孕年龄对胎仔数没有影响。在保存这些数据的4个畜群中，哺乳时间对断奶至受胎间隔有负向影响，而哺乳时间和断奶至受胎间隔对下胎次产仔数有正向影响。由于哺乳期持续时间和断奶至受胎间隔不能单独研究，因此同时研究了它们对产仔数的影响，使用这些组合胎次的分娩至受胎间隔。除1个猪群外，产胎间隔小于36 d，每增加1天活产仔数在0.02 ~ 0.09头之间（P < 0.05）。在这个产胎至受胎间隔内的哺乳持续时间同样影响产仔数。任何畜群产仔数不受产仔至受胎间隔大于35天的影响。除1个母猪群外，产胎间隔大于35 d的母猪产仔数比产胎间隔大于36 d的母猪平均产仔数多0.26 ~ 0.96头（P < 0.1）。在保留这些数据的3个畜群中，1个畜群每次受孕2次交配的平均活窝数大于1次或3次交配的平均活窝数（P < 0.05）。当这些母鼠在3个月的季节期间根据其受孕进行分组时，没有发现季节对产仔数的影响。第1胎次产仔数对后续第3 ~ 7胎次产仔数的影响显著。在产仔至受胎间隔小于36 d的情况下，回归系数在0.11 ~ 0.22之间（P < 0.01）。在分娩至受孕间隔大于35天的雌性中，这种关联仅在一个群体中显着。（摘要删节为400字）
The influence of 7 factors on litter size for the combined parities 3 through 7 (age at conception of the first litter, parity-1 litter size, duration of lactation in the preceding parity, weaning-to-conception interval in the preceding parity, farrowing-to-conception interval in the preceding parity, number of matings per conception, and month of conception) was investigated in 11,929 litters from 5 commercial herds. Age at conception of the first litter did not influence litter size in these parities in any herd. In the 4 herds that kept such data, duration of lactation negatively influenced the weaning-to-conception interval, and duration of lactation and weaning-to-conception interval positively influenced the litter size in the next parity. Because the effects of duration of lactation and weaning-to-conception interval could not be investigated separately, their effects on litter size were simultaneously investigated, using the farrowing-to-conception interval for these combined parities. In all herds except one, the increase in live litter size was between 0.02 and 0.09 pig for each day increase in the preceding farrowing-to-conception interval less than 36 days (P less than 0.05). Duration of lactation within this farrowing-to-conception interval similarly influenced litter size. Litter size in litters of any herd was not affected by a preceding farrowing-to-conception interval greater than 35 days. In all herds except one, mean litter size of females with a farrowing-to-conception interval greater than 35 days was 0.26 to 0.96 pig greater (P less than 0.1) than for females with a farrowing-to-conception interval greater than 36 days. In 1 of 3 herds that kept such data, 2 matings per conception resulted in a larger mean live litter size than 1 or 3 matings (P less than 0.05). When these females were grouped on the basis of their conception during one of the 3-month seasonal periods, no influence of season on litter size was found. The effect of parity-1 litter size on litter size of subsequent parities 3 through 7 was significant. The regression coefficient ranged from 0.11 to 0.22 (P less than 0.01) in the farrowing-to-conception interval less than 36 days in all herds. In females with a farrowing-to-conception interval greater than 35 days, this association was significant only in one herd.(ABSTRACT TRUNCATED AT 400 WORDS)