How much does nutrition impact the reproductive rates of cattle? According to Dr. Rick Funston, UNL Beef Reproductive Specialist, “The nutritional status of animals is difficult to measure, and this complicates the interpretation of nutrition x reproduction interactions. An animal’s nutritional status is usually assessed by changes in its live weight and body condition. However, these are long term changes while many of the events of reproduction, e.g. ovulation, fertilization, and placentation, take only a short time.”
Research has shown an increase in pregnancy rates with a “Flushing Effect”. In other words, cattle bred on an increasing plane of nutrition have exhibited higher pregnancy rates than cattle bred on a declining plane of nutrition. For example, according to this research a cattle herd being bred in June for March calves will have a higher rate of conception than a herd being bred in August for May calves due to the higher quality forage found in the pastures in June versus August. A breeder can use this knowledge to his or her advantage when trying to increase the reproductive rates in their herd whether that be altering their herd’s breeding season or supplementing the poorer quality forage later in the year.
Environmental factors, of course, affect forage quality. On a dry year when drought conditions are imminent, supplementation will be needed to bolster the poorer quality forage found in pastures. Even on ideal forage growing years supplementation should be considered. The Gudmundsen Sandhills Laboratory has observed that heifer calves and first calf heifers receiving a 30% protein cake had higher breeding rates than those who did not receive the supplement.
Before breeding season this year consider your herd’s nutritional needs and the quality and quantity of your forage when trying to increase your herd’s reproductive rates. Remember you fed these cows all winter; don’t give up right before you turn the bulls out. For more information contact your local United Farmers Cooperative.