FOLLOW-UP CHECKS ON REPRODUCTIVE AND REAR ING PERFORMANCE OF BIOTECHNICALLY CONTROLLED SOW HERDS IN PRODUCTION UNITS WITH 1,000 TO 1,275 PLACES

The development of mating performance traits, litter quality and reari ng performance traits was studied on the basis of performance data rec eived from 36-38 piglet production units housing 1,000 to 1,275 sows e ach during a period from 1975 to 1989. The applied reproduction manage ment in this units included the comprehensive use of artificial insemi nation in combination with biotechnical procedures for the control of heat and ovulation by sows and gilts. The average weaning time was 34 days. Comparing the both periods for interpretation 1975-1979 and 1985 -1989 an increase of the average farrowing index from 2.09 to 2,17 lit ters per breeding sow and year; of the farrowing rate from 71,5% to 77 ,6% and the number of weaned piglets per breeding sow and year has bee n obtained. However an improvement neither of the number of piglets su itable for rearing nor of weaned piglets per born litter could be rece ived. The litter weight 95 as a complex trait to evaluate the total pr oductivity was increased from average 259,9 kg (1978, 1979) to 279 kg (1988, 1989).