Evaluation of Teat Ultrasound Measurements for Diagnosis of Subclinical Mastitis in Holstein Dairy Cow
The aim of this study was to evaluate the use of teat ultrasound measurements for diagnosis of subclinical mastitis (SCM) in one hundred ten (110) teats from 110 Holstein dairy cows, 3-6 years old, 1-4 parity and 19-45 kg/day milk production. Teat–canal length (TCL), teat–end width (TEW), teat–wall thickness (TWT), teat–cistern width (TCW), and the ratio between teat–cistern width to teat–wall thickness (TCW/TWT) were measured by ultrasonography using an ultrasound scanner with a 7.5 MHz linear probe in 55 california mastitis test (CMT) positive and 55 CMT negative cases. SCM cases were samples that had both CMT and bacteriological culture–positive results. Results showed that there were 45 normal and 46 SCM cases. TCL,TWT and TEW were similar in normal and SCM cases (P>0.05), and TCW and TCW/TWT were lower in SCM animals than in healthy animals (P<0.05) with the cut-off point of 1.05 cm and 1.49 cm, respectively. The results suggest that measurements of TCW and TCW/TWT can be used to assist in the detection of subclinical mastitis in Holstein dairy cows.
Key words: dairy cow, Holstein, subclinical mastitis, teat, ultrasound