[Back fat thickness and fertility in Brown Swiss cows]

In a total of 94 cows the mean back fat thickness (BFT) on Day 275 of pregnancy and 2 to 3 days after calving (peripartal) as well as between Days 42 and 44 post partum (postpuerperal) has been examined sonographically. Based on their BFT levels all examined cows have been divided into three groups: overconditioned, optimal conditioned and underconditioned cows. Cows which were peripartal overconditioned had more often ovarian cysts (p < 0.05) and were culled more frequently (p < 0.1) because of infertility than peripartal cows which were optimal or underconditioned. Nevertheless, the interval from calving to conception of peripartal cows being in different physical conditions was not significantly different. Postpuerperal cows which were overconditioned had more often ovarian cysts (p < 0.05) and were more frequently (p < 0.05) slaughtered because of infertility than postpuerperal cows which were optimal or underconditioned. Postpuerperal cows which were over- or underconditioned had a significantly longer interval from calving to conception than cows which were optimal conditioned 6 weeks after calving. The correlation coefficient between peripartal and postpuerperal BFT was 0.82 (p < 0.05). The decrease of BFT between the peripartal and postpuerperal timepoint had no significant influence on the frequency of ovarian cysts, the interval from calving to conception and the infertility caused culling rate.