Influence of growth rate, backfat thickness and meatiness on reproduction efficiency in Landrace gilts

Abstract

In the nucleus herd and subsequent multiplication herd of the Landrace(L) breed in 262 gilts farrowed after the first insemination we analysedthe influence of various levels of average daily weight gain from birthin the performance test in the field (ADGI) and till mating (ADG2),average backfat thickness (mm) in the performance test (BF1) and atmating (BF2) or lean meat percentage (LM1 and LM2) on the age and weightat mating and at farrowing, on the number of piglets born, piglets bornalive and weaned ones and litter weight at 21 days. Based on the studiedtraits the gilts were divided into intervals for the evaluationaccording to the average and standard deviation ( = x + s). A significant influence of ADG1 and ADG2 on the weight at thefirst insemination was observed (P < 0.01, P < 0.001). The age andweight after farrowing were affected by ADGI to a greater extent (P < 0.001), the litter weight at 21 days(sows' milk production) and the number of weaned piglets (P < 0.05).ADG2, however, affected only the number of piglets born and of pigletsborn alive per litter (P < 0.05, P < 0.001). BF1 affected only the ageat the first insemination or at farrowing (P < 0.05) and the number ofpiglets at the age of 21 days (P < 0.05). BF2 affected the number ofpiglets born, those born alive and the weaned ones (P < 0.05, P < 0.01),the litter weight at 21 days (P < 0.001) and the number of piglets at 21days (P < 0.05, P < 0.01). The lean meat percentage ascertained in theperformance test (LM1) did not significantly affect any studiedreproduction trait. A significant influence of LM2 on the age at thefirst insemination or at farrowing was proved (P < 0.05, P < 0.01) aswell as on the weight at the first fertile insemination (P < 0.001). Anincreased percentage of lean meat had a negative impact on the number ofpiglets born and piglets born alive (P < 0.05), on litter weight at 21days (P < 0.01), number of piglets at the age of 21 days (P < 0.001) andon the number of weaned piglets (P < 0.05, P < 0.01). A more significantinfluence of the higher growth ability of gilts on the reproductivetraits was detected in the performance test. On the contrary, at theperiod of mating the reproductive traits were affected by backfatthickness and meatiness to a greater extent.