Evaluation of intra- and inter-rater agreement on ultrasound measurements of dairy cow teats by operators with different experience levels

Ultrasound is a valuable, non-invasive technique. It allows for detailed examination, precise measurement, and effective monitoring of teats in dairy cows. This study aimed to evaluate the reliability of ultrasound measurements of teats in dairy cows, specifically focusing on intra- and inter-rater agreement between operators with different levels of experience. The study included 51 healthy Holstein cows, with two operators (experienced and inexperienced) performing measurements on ultrasound images obtained before and after milking. The parameters analyzed were teat-canal length (TCL), teat-end width (TEW), teat-wall thickness (TWT), and teat-cistern width (TCW). Differences in teat measurements before and after milking, as well as between operators, were assessed using the Wilcoxon Signed Rank test and the Mann-Whitney U test, respectively. Intra- and inter-rater agreement was calculated using the intra-class correlation coefficient (ICC). Statistical significance was set at p < 0.05. A total of 402 ultrasound images were analyzed. Significant differences were found in TCL, TWT, and TCW before and after milking, while TEW remained unaffected. Statistically significant differences in TWT and TCW were observed between the two operators, while TCL and TEW did not show significant differences. Intra-rater agreement for the experienced operator was excellent, and for the inexperienced operator, it was good. Inter-rater agreement ranged from good to excellent for most parameters, except for TWT, where it was poor. The study confirms that both milking and operator experience influence teat measurements. However, with proper training, ultrasonography can be a reliable tool for assessing udder health in dairy cows, supporting its use in field conditions.