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

In the nucleus herd and subsequent multiplication herd of the Landrace (L) breed in 262 gilts farrowed after the first insemination we analysed the influence of various levels of average daily weight gain from birth in the performance test in the field (ADG1) and till mating (ADG2), average backfat thickness (mm) in the performance test (BF1) and at mating (BF2) or lean meat percentage (LM1 and LM2) on the age and weight at mating and at farrowing, on the number of piglets born, piglets born alive and weaned ones and litter weight at 21 days. Based on the studied traits the gilts were divided into intervals for the evaluation according to the average and standard deviation (≤ x - s; x - s; x + s; ≥ x + s). A significant influence of ADG1 and ADG2 on the weight at the first insemination was observed (P < 0.01, P < 0.001). The age and weight after farrowing were affected by ADG1 to a greater extent (P < 0.001). With increasing values of weight gain a higher number of piglets per litter was observed. ADG1 affected the number of piglets born and also of piglets born alive (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 piglets born alive per litter (P < 0.05, P < 0.001). BF1 affected only the age at the first insemination or at farrowing (P < 0.05) and the number of piglets at the age of 21 days (P < 0.05). BF2 affected the number of piglets 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 21 days (P < 0.05, P < 0.01). The lean meat percentage ascertained in the performance test (LM1) did not significantly affect any studied reproduction trait. A significant influence of LM2 on the age at the first insemination or at farrowing was proved (P < 0.05, P < 0.01) as well as on the weight at the first fertile insemination (P < 0.001). An increased percentage of lean meat had a negative impact on the number of piglets born and piglets born alive (P < 0.05), on litter weight at 21 days (P < 0.01), number of piglets at the age of 21 days (P < 0.001) and on the number of weaned piglets (P < 0.05, P < 0.01). A more significant influence of the higher growth ability of gilts on the reproductive traits was detected in the performance test. On the contrary, at the period of mating the reproductive traits were affected by backfat thickness and meatiness to a greater extent.