Influence of age and weight of Landrace gilts at fertile insemination on litter size and longevity

The relationship between age and weight of Landrace gilts both litter size and longevity then culling has been analyzed. The data structure included 1.615 gilts which have been divided in three groups of age at fertile insemination (180-210 days; 211-230 days and 231-260days) and three groups of weights at the same time (90-114 kg; 115-130 kg and 131-170 kg). Management and the nutrition of gilts and sows have been treated at common level of production. Analysis included data from 4 farms and the period of two years production (2009 and 2010). MME - mixed model has been installed to use FYS (Farm, Year and Seasons) and litter as fixed effect and sire influence as random. Significant influence of age and weight on litter size has been recognized. Also those two factors had significant effect on longevity and production of sows. The best results were determined in gilts introduced at the age of 231-260 days and weight class of 131-170 kg. Those factors had significant influence on longevity and life production. Genetic and phenotypic correlations showed high and significant value. All results have been interpreted in 8 tables and 4 graphs.