The effect of age at the first mating and herd size on the lifetime productivity of sows

Abstract

The effect of age at the first mating and herd size were evaluated in the reference Spanish Databank (BDporc) of 37 698 sows born between 1991 and 1995 and with individual lifetime re- cords. The data included dates of births at entrance and culling, first mating, repetitive mating and conception, first farrowing and weaning records. Individual records were validated before the analy- sis by screening them through a tolerance filter in order to eliminate the extreme values from the analysis. The total database of the sows was classified in 7 classes according to age at the first mating ( 270 days) and in 6 classes of herd size ( 800 sows). The total number of litters and num- ber of weaned piglets obtained from each sow during the lifetime production were significantly (P 800 sow-herds. Further- more, a significant (P < 0.001) interaction between age at the first mating and herd size was detected and can be associated with a particular pattern for the herd size class 401-600 sows with the best per- formances obtained for the sows first mated at less than 200 days. For the other herd sizes, the results indicated that sows mated for the first time at the right age, 221-240 days, are more productive, both in the number and size of the parities throughout lifetime production. age at first mating / sow / productivity / performance / longevity / litter size / pigs