Genetic analysis of longevity, length of productive life and lifetime performance in the pig breeds Large White, German Landrace and Pietrain Swine

The objective of this analysis was to describe the development of lifetime performance of sows of the pig breeds Large White (DE), German Landrace (DL) and Pietrain (PI) for an observation period of 6 birth years (1989 to 1994) using mixed linear models. The investigation was based on records of 82,984 litters from 655 DE sows, 13,025 DL sows and 6,487 PI sows. The traits longevity, length of productive life, number of piglets born alive and number of weaned piglets in total life of a sow were analyzed using a linear mixed model. The model used included the effects of the herd, the month and year of birth, the age of first farrowing, the mean farrowing interval between all litters and the average number of piglets born alive per litter. In all these three pig breeds analyzed, lifetime performance increased with some fluctuations during the observed period. The largest increase in the number of piglets born alive and weaned piglets in total lifetime could be observed in the breed DE with 4.4 and 4.3 piglets, respectively. The largest prolongation of longevity and length of productive life with 71 and 60 days, respectively, was reached by PI sows, while the number of piglets born alive and weaned piglets in total lifetime increased by 1.7 and 1.9 piglets. In DL sows, longevity increased by 2 days, number of piglets born alive and weaned piglets in total lifetime by 0.2 and 0.5 animals, but length of productive life decreased by 1 day. The increase of longevity and length of productive life in DE sows was 38 and 35 days, respectively. The age at first farrowing, the mean farrowing interval and the average number of piglets born alive per litter influenced significantly all traits. The optimum time of first farrowing with respect to lifetime performance in DE sows was between day 350 and 380 of life, while the optimum was before day 350 of life in DL and PI sows. The mean farrowing interval associated with the best lifetime performance was between 162 and 189 days in DE sows, between 155 and 175 days in DL sows and between 169 and 182 days in PI sows. Longevity and length of productive life increased by 33 days in DE, by 43 days in DL and by 38 days in PI per piglet born alive per litter. The number of piglets born alive and weaned piglets in the total lifetime of a sow was correlated with number of piglets born alive per litter. The increase was 4.9 and 4.2 piglets in lifetime for DE, 5.6 and 5.0 piglets for DL, and 4.6 and 4.2 piglets for PI, respectively. Heritabilities of longevity and length of productive life were h2 = 0.12 in DE sows, h2 = 0.10 in DL sows and h2 = 0.19 in PI sows. Heritabilities of the number of piglets born alive and weaned piglets in total lifetime of a sow amounted to h2 = 0.14 in DE, h2 = 0.12 in DL and h2 = 0.17 in PI.

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