THE EFFECT OF SEASONS ON SOW BIRTH AND THE LENGTH OF THE CORRECTING PERIOD ON THE PROFITABLE PRODUCTION OF PIGLETS

摘要

There are several different factors that influence the reproductive performance of sows and profitable production. Certainly, one of them is the season of birth. In order to ensure better utilization of pigs* reproductive potentiality, it is neccessary to use a correcting period for sows in the best way depending on the season of birth. A correcting period is the time from introducing sows into production until their first farrowing. Shortening the unproductive phase costs of feeding become shorter,which reduces the price of pigs. The study was performed on 1540 sows in the period from 1993-1997. From the herd record, needed data were taken for every sow, and the periods of productive and unproductive phases was determined, as well as the number oflive bom piglets per litter and their costs. The sows were divided into three groups, depending on the month of birth. For making an economic model, the following elements were considered: all the sows enter production in the seventh month, the productive phase is a biological constant (the length of gravidity is 115 days), and the unproductive phase represents the difference in the estral phase which may differ by 20 days, depending on the group.