Timing of Artificial Insemination Using Sexed or Conventional Semen Based on Automated Activity Monitoring of Estrus in Holstein Heifers

Investigations on the optimum timing of artificial insemination (AI) following automated activity monitoring (AAM) depending different types semen in heifers are limited and part show controversial results. Therefore, objective this observational study was to determine association between AI using characteristics estrus (i.e., onset, peak, end estrus) pregnancy per (P/AI) Holstein heifers. Heifers were fitted with a neck-mounted AAM system inseminated frozen conventional sexed semen. The (n = 4159) from 2858 six commercial dairy farms Germany upon alert an evaluated. Estrous intensity classified based peak into low (35 89 index value) high (90 100 value). We detected quadratic interval onset P/AI (p 0.02). greatest observed for 9 32 h after estrus. intervals not associated ≥ 0.05). (50.1%) had greater compared (43.3%; p 0.03). There no interactions or type estrous (50.5% vs. 53.0% intensity; 0.37). In conclusion, inseminating estrus, as by AAM, optimized regardless type.