Influence of age at first farrowing of maternal breed sows on their reproductive performance

The aim of the study was to determine the relationship between the age of the first farrowing of maternal breed sows Polish Large White (PLW) and Polish Landrace (PL), and the parameters of the previously conducted life performance test and the results of the reproductive performance. Offspring of 4-5 litters born in 2009-2014 years from 564 PLW and 300 PL sows were subjected to the analysis. A total of 4,064 litters. In the performance test took into the consideration the body weight on the day of the assessment, standardized daily gains, and standardized thickness of backfat, the percentage of meat content in a carcass and the value of the selection index. In the reproductive assessment took into account the age of the first farrowing, the number of alive and dead piglets in a litter, the number of piglets in 21st day of life, the mortality rate of piglets, the percentage of gilts in a litter. The obtained results were compiled and analyzed in three groups of sows formed according to the age of the first farrowing: group I <= 340 days, II 340-380 days and III > 380 days. The age of the first farrowing varied between the groups of sows and ranged from 322 to 400 days. It was shown that the gilts demonstrating in the performance test the greatest body weight, the largest gains, and the smallest meatiness obtained the highest index value and were characterized by the youngest age of the first farrowing (P<0.01 and P<0.05). The number of born and reared piglets till 21st day, was not significantly related to the age of the first farrowing.