Prevalence and influence of clinical and subclinical mastitis in the service period of dairy cows in Tarumirim (MG)

Résumé

The objective was to assess the prevalence and influence of clinical and subclinical mastitis during the service period of cows in a herd in Tarumirim (MG), from October 2019 to May 2020. Around 65 Gir x Holstein and Guzerá x Holstein lactating crossbred cows were evaluated. Subclinical mastitis was diagnosed by means of the California Mastitis Test (CMT), and clinical mastitis, by means of the strip cup test and the animals' clinical signs. Pregnancy after calving was diagnosed by the rectal palpation method, with the aid of ultrasound. The time from calving to conception was considered as the service time. The prevalence rates of clinical and subclinical mastitis were 2.9 and 63.7%, respectively, throughout the experimental period. The mean service period was shorter (p<0.05) in healthy cows (63.1 days) than in cows with subclinical mastitis (88.5 days) and clinical mastitis (111.2 days). The service period increased by 30.9 days for each mammary quarter with clinical mastitis (p<0.05). With each increase in the degree and days of duration of clinical and subclinical mastitis, the service period rose by 25.4 and 6.5 days, and 8.5 and 0.6 days, respectively (p<0.05). Therefore, mastitis increases the service period of dairy cows. Good milking hygiene and animal handling practices should be adopted in order to reduce the prevalence of mastitis in the herd.