Associations between climate variables and beef cow fertility following fixed-time artificial insemination during an 11-years period in the central region of Chile

Abstract Global average surface temperature is expected to rise throughout this century affecting key aspects of livestock productivity, including animal health and reproduction. The frequency of extremely hot days during summer in Chile and South America is expected to double over the next years resulting in environmental conditions that may affect beef cattle. The objective of the present study was to analyze the impact of climatic variables, including temperature, rainfall, relative humidity and solar radiation on pregnancy rates of crossbred beef cows in central Chile over a period of 11 years following an estradiol-based fixed time artificial insemination (FTAI) program. Climate data and records from 1,011 beef crossbreed cows belonging to 15 small holders from the central region of Chile included in a FTAI program were analyzed during an 11-year period. Although climate conditions evidenced an intense drought and raising air temperature, probability of pregnancy of cows were not significantly different during this period. Cows with calving to pregnancy interval (CPI) > 75 days had 78% higher probability of pregnancy in comparison with CPI < 60 days. Moreover, cows in intervals of body condition score (BCS) 2.76-3.00 and 3.01-4.00 had significantly higher PR (PR = 57.5 and 62.3, OR = 1.86 and 3.52, respectively) compared to cows with BCS < 2.76. In conclusion, beef cows following a FTAI program in the central region of Chile included in this study did not show significant reduction in reproductive performance between years 2014 and 2024. However, cows with lower BCS (< 2.75) and lower CPI (< 60 days) had fewer probability of pregnancy.