Factors affecting length of productive life in Swedish commercial sows
Factors affecting length of productive life in Swedish commercial sows
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DOI：
10.2527/jas.2007-0310
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发表时间：
2008-02-01
影响因子：
3.3
通讯作者：
Andersson, K.
中科院分区：
文献类型：
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作者：
Engblom, L.;Lundeheim, N.;Andersson, K.
本研究的目的是调查可能影响瑞典杂交母猪（长白猪×约克郡）生产寿命长度的因素。数据集包括2001年至2004年期间在21个商业仔猪生产群中分娩的20，310头母猪。生产寿命（PL）定义为第一次分娩与移除或终止数据收集之间的天数。除了PL的总体风险分析外，还分析了另外4个长寿性状（竞争风险分析）：生殖障碍决定的PL长度（RPL），乳房问题决定的PL长度（UPL），跛行决定的PL长度（LPL）和死亡决定的PL长度（MPL）。通过使用生存分析进行分析，应用具有6个时间依赖性变量和1个时间独立变量（首次分娩时的年龄）的Weibull模型。对PL的似然函数贡献最大的因素是分娩后天数，其次是胎次、畜群x年份组合、出生仔猪总数、断奶与下一次分娩之间的天数、分娩月份和首次分娩时的年龄。对于所有4个竞争风险性状，对似然函数贡献最大的因素是分娩后天数、畜群x年份组合和胎次，性状之间的顺序不同。对于PL、UPL和LPL，分娩后（断奶后）30至40天的移除风险最大（P < 0.001）。然而，对于MPL的危害是最大的分娩后（0至10天），和RPL的危害在分娩后70至100天达到峰值。与产次1相比，产次2 ~ 7的PL取出风险较小，产次8的PL取出风险较大（P < 0.001）。RPL、UPL和LPL的风险在产次1时最大（P < 0.01），而MPL的风险随着产次数的增加而增加，从产次9开始显著增加（P < 0.001）。窝产仔数在9头或以下的母猪被淘汰的危险性高于窝产仔数在12 ~ 13头的母猪（P < 0.001）。从断奶到下一次分娩间隔120 ~ 122 d的时间段的去除风险最低（P < 0.001）。分娩月份对PL的影响不明显。第一次分娩时14月龄或更大的母猪比年轻母猪的移除风险高20%（P < 0.001）。在所有产次中，较小窝仔的移除风险更大，但在较大产次中更突出。总体而言，分娩后天数是母猪移除的主要风险因素。断奶后不久，去除风险是最大的，这一高峰增加了更大的奇偶数。
The objective of this study was to investigate factors that might influence the length of productive life in Swedish crossbred (Landrace x Yorkshire) sows. The data set consisted of 20,310 sows farrowing between 2001 and 2004 in 21 commercial piglet-producing herds. Productive life (PL) was defined as the number of days between first farrowing and removal or termination of data collection. In addition to the overall risk analysis of PL, another 4 longevity traits were analyzed (competing risk analyses): reproductive disorder-determined length of PL (RPL), udder problem-determined length of PL (UPL), lameness-determined length of PL (LPL), and mortality-determined length of PL (MPL). Analyses were performed by using survival analysis, applying a Weibull model with 6 time-dependent and 1 time-independent variable (age at first farrowing). The factor with the largest contribution to the likelihood function for PL was days after farrowing, followed by parity, the herd x year combination, the total number of piglets born, days between weaning and next farrowing, farrowing month, and age at first farrowing. For all 4 competing risk traits, the factors contributing most to the likelihood function were days after farrowing, the herd x year combination, and parity, with a varied order between traits. The hazard for removal was greatest 30 to 40 d after farrowing (after weaning) for PL, UPL, and LPL (P < 0.001). However, for MPL the hazard was greatest just after farrowing (0 to 10 d), and for RPL the hazard peaked at 70 to 100 d after farrowing. The hazard for removal was, compared with parity 1, less in parities 2 to 7 and greater from parity 8 for PL (P < 0.001). The hazard was greatest in parity 1 (P < 0.01) for RPL, UPL, and LPL, whereas for MPL the hazard increased with greater parity number and was markedly greater from parity 9 (P < 0.001). Sows with litters of 9 piglets or less had a greater hazard for removal than sows with litters of 12 to 13 piglets (P < 0.001). Intervals between 120 and 122 d from weaning to the next farrowing showed the lowest hazard for removal (P < 0.001). The influence of farrowing month displayed no clear pattern for PL. Sows of 14 mo or older at their first farrowing had a 20% greater hazard for removal than younger sows (P < 0.001). The hazard for removal was greater for smaller litters in all parities but was more accentuated in greater parities. Overall, days after farrowing was the main risk factor for sow removal. Removal hazard was greatest shortly after weaning, and this peak increased with greater parity number.