The 10 days prior to conception to approximately 20 days after are critical for optimum ovum development and embryo survival in beef cows, says University of Nebraska animal scientist Terry Mader, PhD. An analysis of 10 years of reproductive data from a herd of crossbred cows in southeast Nebraska found that conception rates are clearly lower during summers when it’s hot during the breeding season than during cooler summers. For each 1 degree Fahrenheit that temperatures are above normal, conception rates tend to be reduced about 1 percent. Mader offers these tips to minimize heat and humidity stress in cows during the breeding season:
* For spring-calving herds, attempt to get cows bred by July 1.
* Minimize cattle activity and movement during breeding season, especially when it’s hot. Physical activity can raise a cow’s body temperature 1 to 2 degrees.
* If you must move or work cattle, do it very early in the morning when it’s cooler, to allow cattle two to three hours to cool down after working or moving.
* Provide plenty of clean water as it’s one of the most useful tools for cooling cattle.
* Ensure water access and availability is not limited in mob-grazing and intensive pasture-rotation systems.
* Provide shade or a place for cattle to cool off when possible.
* Control flies to discourage bunching and physical activity associated with cattle fighting flies.
* Make sure bulls are kept cool as well as cows.