Analyse des composantes de la productivité numérique des truies

Open Access
Publisher Website
Google Scholar
Abstract
The number of piglets reared/sow per yr of reproductive life (Pn) and per yr of presence on the farm (P''n) observed in 3464 French pig herds were analyzed taking into account the size of the herd. Classes (4) of herds were set up based on the number (N) of litters weaned in the course of the reference period. A significant improvement in Pa and P''a was observed as the herd size increased. As the number of litter weaned during the year is less than 50 or greater than 180, Pn and P''n rose respectively from 18.3-20.0 and from 15.9-17.6 piglets weaned/sow. This improvement was due essentially to an acceleration in the rhythm of reproduction as a result of a reduction by 9 days of the milking period, by 12 days of age at 1st farrowing, by 7 days of the weaning-fertilization period and by 8 days of the last weaning-culling period. Litter size was slightly smaller in the biggest herds (10.0 vs. 10.2) whereas the mortality rate is 1% lower in these herds. Multiple linear regression equations show that whatever the herd size, P''n was determined by 4 significant variables in the following order: litter size at birth, mortality rate from birth to weaning, the last weaning-culling interval and, in 3 out of 4 cases the length of the milking period. The age at 1st farrowing is in 5th place except in the 2nd class where it is in 5th place. The first 2 variables account for from 36-56% the variance of P''n, whereas the 4 significant variables taken together account for 53% the variance in the smallest herds and 76% the largest. Taking into account the tendency for herds to become larger and more specialized, efforts should be directed at increasing litter size at birth and at lowering mortality rate among suckling piglets.

This publication has 0 references indexed in Scilit: