Koketsu Yuzo, Iida Ryosuke, Piñeiro Carlos
School of Agriculture, Meiji University, Higashi-mita 1-1-1, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan.
PigCHAMP Pro Europa S.L., c/Santa Catalina 10, 40003, Segovia, Spain.
Porcine Health Manag. 2021 Jan 4;7(1):4. doi: 10.1186/s40813-020-00182-y.
Piglet pre-weaning mortality (PWM) is one of the biggest problems regarding sow performance and piglet welfare. Recently, PWM has increased in some countries, but it is not known if there are similar increases in other countries, nor whether increased PWM is related to either increased numbers of piglets born alive (PBA) or to sow herd size. So, the objectives of the present study were 1) to explore the trend in PWM in Spanish sow herds over a recent 10-year period, along with related measurements such as PBA, stillborn piglets, herd productivity and herd size; and 2) to examine the relationships between PWM and the related measurements.
Herd-level annual data from 2007 to 2016 for 91 herds in Spain were abstracted from a sow database compiled by a veterinary consultancy firm that asked client producers to mail data files on a regular basis. The database software automatically calculated herd-level PWM (%) as follows: the total number of piglets born alive to a sow completely weaned during a year (TPBA) minus the total number of piglets weaned by the completely weaned sow during the year divided by TPBA × 100. All the statistical analyses were performed by using SAS University Edition. A growth curve model was applied to incorporate correlations for all of the observations arising from the same farm.
Over the 10 years, herd means of PWM (standard deviation) increased from 11.9 (4.1) % to 14.4 (3.2) %, and mean PBA increased by 1.9 pigs. Mean age of piglet death during lactation increased by 3.8 days, and later years were significantly associated with herd size and the number of piglets weaned per sow per year (PSY; P < 0.05). Higher PWM was associated with more PBA, more stillborn piglets and small-to-mid herds (lower than the median size: < 570 sows; P < 0.05). Also, there was a significant interaction between the herd size groups and PBA for PWM (P < 0.05): as PBA increased from 9 to 14 pigs, PWM increased by 9.6% in small-to-mid herds, compared with an increase of only 6.6% in large herds (> 570 sows). Furthermore, as PWM decreased from 18 to 8%, herd productivity measured as PSY increased by 2.2 pigs in large herds, compared with only 0.6 pigs in small-to-mid herds.
Large herds were better than small-to-mid herds at alleviating the association between increased PBA and increased PWM. Also, the relationship between decreased PWM and increased herd productivity was improved more in large herds than in small-to-mid herds.
仔猪断奶前死亡率（PWM）是影响母猪生产性能和仔猪福利的最大问题之一。最近，一些国家的仔猪断奶前死亡率有所上升，但尚不清楚其他国家是否也有类似的上升情况，也不清楚仔猪断奶前死亡率的上升是否与活产仔猪数量（PBA）的增加或母猪群规模有关。因此，本研究的目的是：1）探讨西班牙母猪群在最近10年期间的仔猪断奶前死亡率趋势，以及相关指标，如活产仔猪数、死产仔猪数、猪群生产力和猪群规模；2）研究仔猪断奶前死亡率与相关指标之间的关系。
从一家兽医咨询公司编制的母猪数据库中提取了西班牙91个猪群2007年至2016年的年度猪群水平数据，该公司要求客户生产者定期邮寄数据文件。数据库软件自动计算猪群水平的仔猪断奶前死亡率（%），计算方法如下：一年内完全断奶母猪的活产仔猪总数（TPBA）减去该完全断奶母猪当年断奶的仔猪总数，再除以TPBA×100。所有统计分析均使用SAS大学版进行。应用生长曲线模型纳入来自同一猪场的所有观测值之间的相关性。
在这10年中，猪群的仔猪断奶前死亡率均值（标准差）从11.9（4.1）%上升到14.4（3.2）%，活产仔猪数均值增加了1.仔猪死亡的平均哺乳期年龄增加了3.8天，后期与猪群规模和每头母猪每年断奶仔猪数（PSY）显著相关（P<0.05）。较高的仔猪断奶前死亡率与更多的活产仔猪数、更多的死产仔猪数以及中小规模猪群（规模低于中位数：<570头母猪；P<0.05）有关。此外，猪群规模组与活产仔猪数之间在仔猪断奶前死亡率方面存在显著交互作用（P<0.05）：随着活产仔猪数从9头增加到14头，中小规模猪群的仔猪断奶前死亡率增加了9.6%，而大规模猪群（>570头母猪）仅增加了6.6%。此外，随着仔猪断奶前死亡率从18%降至8%，以PSY衡量的猪群生产力在大规模猪群中增加了2.2头仔猪，而在中小规模猪群中仅增加了0.6头仔猪。
在缓解活产仔猪数增加与仔猪断奶前死亡率增加之间的关联方面，大规模猪群比中小规模猪群表现更好。此外，仔猪断奶前死亡率降低与猪群生产力提高之间的关系在大规模猪群中比在中小规模猪群中改善得更多。
