The prevalence of heifer mastitis and its associated risk factors in Huanggang, Central China.

The purposes of this study were to determine the prevalence of heifer clinical mastitis (HCM) and heifer subclinical mastitis (HSCM), isolate HCM-causing bacteria, and assess the association of some risk factors in Huanggang, Central China. A total of 1,374 lactating heifers from three dairy farms were examined in the present study; 22.64% of heifers were positive for mastitis, out of which, 3.86 and 18.78% were with HCM and HSCM, respectively. Of the 67 HCM samples, 91.05% were single growth, 7.46% mixed growth, and 1.49% no bacterial growth. Coagulase-negative staphylococci (CNS) accounted for 30.98% of the isolates followed by Escherichia coli (29.58%), Staphylococcus aureus (16.9%), and Streptococcus uberis (11.27%). Logistic regression analyses showed that heifer milk yield lower than 3 L had the highest prevalence of HCM compared to heifer milk yield of more than 3 L (P < 0.01), and prevalence of HCM was significantly high in heifers with the presence of teat lesions (P < 0.01). Moreover, the heifer milk yield lower than 3 L had the highest prevalence of HSCM compared to heifer milk yield of more than 3 L (P < 0.01). These two factors were significantly associated with the occurrence of heifer mastitis, which needs to be considered in the prevention and control strategies of the disease.