Uterine diseases in dairy cows: understanding the causes and seeking solutions

Uterine diseases such as metritis and endometritis are highly prevalent in high producing dairy cows. These diseases lead to impaired welfare and fertility, and result in economic loss. The objective of this review article is to provide the current understanding of the underlying causes of uterine diseases and to provide some strategies to prevent them. The causes of uterine diseases are complex and multifactorial; therefore a holistic approach must be taken when trying identity the causes or prevent them. The dairy cow undergoes a state of negative energy, mineral and vitamin balance during the transition into lactation, which leads to immunosuppression and increased susceptibility to disease. The main risk factors for uterine diseases are primiparity (for metritis only), dystocia, male offspring, twins, stillbirth, abortion, prolapsed uterus, retained placenta (RP), ketosis, and hypocalcemia. Prevention strategies should be focused on maximizing cow comfort and dry matter intake (DMI), preventing hypocalcemia and hyperketonemia, preventing dystocia, prolapsed uterus, abortion, stillbirth and RP. Maximization of cow comfort and DMI can be achieved with appropriate housing and cooling. Management strategies to prevent metabolic and calving related problems include the use of anionic diets, the use of feed additives such as monensin and rumen protected choline, implementation of sound vaccination programs, and the use of sexed semen. Trace mineral and vitamin supplementation beyond what is fed in the diet is still controversial; however some trials have shown a decrease in RP and stillbirths. Prophylactic treatment of cows at high risk for metritis with PGF2α and/or oxytocin is not warranted because there is no beneficial effect. Prophylactic treatment of cows at high risk for metritis with NSAIDs is contraindicated because it has been found to decrease DMI and increase the degree of negative energy balance; therefore, leading to an increase in the risk of RP and metritis. Prophylactic treatment of cows at high risk for metritis with estradiol is contraindicated because there is no beneficial effect on the prevention of metritis and there is a negative effect on long term fertility. Prophylactic treatment of cows at high risk for metritis with antibiotics can reduce the incidence of uterine disease but has no positive long term effects on fertility; therefore, decision to implement prophylactic antibiotic treatment should be based on welfare, economic and legal considerations. Given that most treatments are not very efficacious, efforts should be focused on management strategies to decrease metabolic problems such as hypocalcemia and ketosis, and to prevent risk factors such as dystocia, male calves, abortions, stillbirths, and retained placenta.