Udder Health is Related to Reproductive Performance

During the past five years evidence has been accumulating showing a relationship between mastitis and early embryonic death or abortion. Research conducted at the University of Florida examined the relationship between clinical mastitis and abortion during early pregnancy. The results showed that cows with clinical mastitis during the first 45 days of pregnancy were at 2.7 times higher risk of abortion than cows without mastitis. The data indicated there was no difference in abortion rate when clinical mastitis occurred beyond 45 days of pregnancy. Possibly the fetus is more susceptible to abortion during the period of placental attachment.

Work from the University of Tennessee where cows were classified as clinical, subclinical, transitioned from subclinical to clinical or uninfected showed that not only clinical but even subclinical mastitis caused a negative effect on reproductive performance. Furthermore, there was a tendency for cows that transitioned from subclinical to clinical mastitis between first service and time of confirmed pregnancy to have the most days open and services per conception.

Last month at the American Dairy Science Association annual meeting in St. Louis scientists from the University of Idaho reported the effects of clinical mastitis, other diseases or a combination of both problems on reproduction. This study involved 963 cows. Cows with clinical mastitis or a combination of mastitis and other diseases had significantly more days open and services per conception compared to cows with another disease alone or healthy cows. These results further document the negative effect of mastitis on reproduction and this effect is exacerbated when cows also experience another disease or complication during the breeding period.

We feel the primary cause of this costly relationship is that endotoxins released during mastitis increases the level of prostaglandin from the uterus regressing the corpus luteum resulting in embryonic or fetal mortality. The mechanisms of action whereby other metabolic or infectious diseases impact reproduction are varied. Certainly the combination of these negative physiological responses places the embryo at greater risk. Achieving good conception rates is a constant challenge. With embryonic and fetal mortality rates approaching 15 to 20%, it is critical to maintain udder health and minimize the incidence of metabolic problems so these rates don’t accelerate. These complications may be the major bottleneck restricting profitable reproductive performance on many dairy operations. The cascade of events associated with mastitis and other diseases effects profitability in several areas: production, reproduction, and veterinary expenses. Calculate the incidence of clinical mastitis and other postpartum problems on a routine basis. If found to be a problem, set-up a strategy with your veterinarian to correct the problem.

Michael O’Connor, Dairy and Animal Science Extension