Some factors affecting the number of days open in Argentinean dairy herds

摘要: The objective of this study was to estimate the relative contribution factors affecting how quickly cattle become pregnant in Argentine dairy herds. Data from 76,401 cows 249 herds were analyzed. A hazard model used explore days open (DO). considered milk yield, lactation number, calving season, and breeding technique (i.e., type service: artificial insemination [AI], or combined service). Cows with lower yield had 1.09 1.38 higher likelihood than those (P < 0.0001). number DO increased linearly an increasing lactations fall-winter a shorter interval conception summer. rate for service 1.27; therefore, more likely during observation period bred by AI. difference between high versus low smaller when dairies AI as main they service. Furthermore, using mainly (5693.7 L) (7684.4 L). Although season contributed explain DO, influence production level, service, interaction them also associated reproductive efficiency