Evaluation of a milk-flow assessment technique in dairy cows with normal teat canals or stenotic teat canals.

Objective: To assess the usefulness and reliability of a milk-flow measurement technique and the values obtained in unobstructed teats and teats with teat canal stenosis in dairy cows.

Animals: 16 Holstein cows.

Procedures: Teats were assessed via hand milking and classified as unobstructed or partially obstructed. Partially obstructed teats were further categorized according to the anatomic location of the obstruction via ultrasonography into teat canal obstruction (TCO) and obstruction at the proximal portion of the teat canal (Fürstenberg rosette obstruction [FRO]) The milk-flow characteristics of the teat canal were assessed by measuring the intracisternal pressure at the start (PSL) and at cessation (PCL) of leakage of an infused solution.

Results: The PSL and PCL values among unobstructed teats were not significantly different between lactating and nonlactating cows nor among quarters. In assessment of test-retest intrarater reliability, a high degree of correlation was detected for PSL (correlation coefficient, 0.94; 95% confidence interval, 0.90 to 0.96) and PCL (correlation coefficient, 0.92; 95% confidence interval, 0.86 to 0.95). Teats with TCO and FRO had higher PSL and PCL values, compared with unobstructed teats. Teats with FRO had significantly higher PSL but lower PCL than teats with TCO.

Conclusions And Clinical Relevance: Results indicated the usefulness and reliability of the technique in assessing the milk-flow characteristics of the teat canal. The milk-flow pattern of teats with teat canal stenosis varies depending on the location of obstruction. This technique may be a valuable tool in evaluating the effectiveness of teat canal surgery.