Effects of in utero heat stress on subsequent reproduction performance of first-calf Holstein heifers

Abstract

Aim of study: To determine the reproductive performance of heifers gestated under maternal conditions of heat stress in late gestation. Area of study: Northern Mexico (25° 32’ N, 103° 23’ W). Material and methods: The study included reproductive records of 4976 first-calf Holstein heifers in a hot environment. Main results: Heifers born to cows experiencing no heat stress three months before parturition but with a THI >83 at calving were older (p83 at calving than heifers whose mothers were exposed to <76 or 76-83 (117 and 114 d) at calving. Research highlights: These data suggest that in utero heat stress during the last three months of gestation negatively affects the reproductive performance of first-calf Holstein heifers.

Keywords

• conception rate
• twining rate
• services per pregnancy
• age at first calving
• fetal losses