Milk yield, somatic cell counts, and risk of removal from the herd for dairy cows after covered teat canal injury.

The objective of this study was to evaluate milk yield, somatic cell count (SCC), and risk of removal of a cow from the herd after covered teat injury. Teat injuries were diagnosed and treated by using endoscopy. After treatment, teats were rested for 3 x 3 d. Eighty-one cows referred to the Veterinary Clinic Babenhausen were used for this study. Each cow was matched to three herdmates by breed, age, and calving date. Data on milk yield and SCC were available from the records of the Bavarian milk control board. Test day milk yields and lactational milk yields were equal for cows with covered teat injury and herdmates in the lactation when the injury was diagnosed and in the subsequent lactation. Calving interval in the year the injury was diagnosed and the time cows lived in the herd were also equal. However, covered teat injuries significantly increased test day SCC by 128,000 cells/ml of milk. These injuries also significantly increased the odds of subclinical mastitis (SCC > 100,000 on test day) and the odds of violating European milk shipping regulations (SCC > 400,000 on test day). Because increased SCC was significantly associated with decreased milk yield, cows may not have fully utilized their milk yield capacity after covered teat injury.