SOW LONGEVITY AS AN INDICATOR OF RESISTANCE TO ENVIRONMENTAL STRESSORS

摘要

The longevity and reproductive performance of 190 crossbred Redone sows inseminated with the semen of hybrid Gallia boars were analyzed in this study. The sows were kept on a large commercial farm in optimal environmental conditions, in line with welfare requirements. Sows produced an average of 2.2 litters a year. The total number of litters farrowed was 1380 (7.26 litters per sow on average). The first sows were culled from the herd after the 2nd breeding cycle (5%), whereas the sow characterized by the highest lifetime efficiency and longevity delivered 22 litters (a total of 270 piglets born alive, including 260 weaned piglets). The main reasons for culling were reproductive disorders and lameness, which accounted for 39.7% and 30.7% of all cases, respectively. It should be stressed that sows that delivered at least 7 litters were less often culled from the herd due to high piglet mortality and lameness. The average number of piglets born alive and stillborn piglets per litter was 13 and 0.67,respectively. A positive correlation was found between sow fertility and the size of subsequent Utters (r = 0.17 - p < 0.01), which indicates that sow fertility does not always decreases with age. The group of sows that stayed in the herd for the longestperiod of time (group 5, at least 12 litters) was characterized by the highest fertility (p < 0.01) and a similar number of stillbirths in comparison with the remaining groups. Group 5 sows accounted for 17.4% of all sows in the herd, and group 4 sows (at least 6 litters) - for 36.8%. It can be concluded that sows have a high potential for longevity, which can be fully realized only under optimal environmental conditions (adequate nutrition, housing and sanitary conditions, well-trained staff, veterinary care).em:kozwoj@uwm.edu.pl