Abstract #T56

# T56
Weather-related cold stress on conception rates in Sim-Angus cattle.
Jessica A. Stone*1, Julie D. Weathers1, 1Southeast Missouri State University, Cape Girardeau, MO.

The purpose of this study was to determine how much correlation there was, if any, between temperature, wind chill factor, and pregnancy results. It has been well documented that weather patterns and temperature will affect reproductive efficiency in cattle, as well as other species. The study was conducted in 2013 and again in 2014, using the similar methods. Because of a change in management, 2012 was not eligible for the study because of inconsistency from the following years. The same population of similarly bred Sim-Angus cattle was inseminated using a fixed timed artificial insemination program of a 14-d CO-Synch + CIDR protocol at the David M. Barton Agriculture Research Center in Gordonville, Missouri. In 2013, 41 Sim-Angus cows participated in the study and in 2014, 17 Sim-Angus cows were used. Only 17 were used in 2014 because the entire herd was split equally to create a fall and spring calving herds. By studying the weather patterns 14 d before and after the day of breeding and comparing the pregnancy results of 2013 and 2014, a correlation was found between the temperature, wind chill factor, and pregnancy results (r = −0.6). In 2013, the animals were bred on December 6, where the average temperature was −5°C with a wind chill of −12.94°C at 8:53 a.m. In 2014, the day of breeding was December 12, with an average temperature of 3.88°C and a wind chill of 0.05°C at 8:53 a.m. After comparison of blood samples each year for pregnancy (BioPryn; Moscow, ID), 16 out of 41 animals were pregnant in 2013, giving a conception rate of 39%. In 2014 however, 14 of the 17 animals were bred, giving a conception rate of 82%. More research is forthcoming to determine if this correlation holds true for a larger sample of cattle and more repetitions of the experiment.

Key Words: conception, cold stress, temperature