Inter-Rater Reliability of Scoring Systems for Abomasal Lesions in Quebec Veal Calves

The objective of this study was to determine the inter-rater reliability of current scoring systems used to detect abomasal lesions in veal calves. In addition, macroscopic lesions were compared with corresponding histological lesions. For this, 76 abomasa were retrieved from veal calves in a slaughterhouse in Quebec and scored by four independent raters using current scoring systems. The localisations of the lesions were separated into pyloric, fundic, or torus pyloricus areas. Lesions were classified into three different types, i.e., erosions, ulcers, and scars. To estimate the inter-rater reliability, the coefficient type 1 of Gwet's agreement and Fleiss kappa were used for the presence or absence of a lesion, and the intra-class correlation coefficient was used for the number of lesions. All veal calves had at least one abomasal lesion detected. Most lesions were erosions, and most of them were located in the pyloric area. Overall, a poor to very good inter-rater agreement was seen for the pyloric area and the torus pyloricus regarding the presence or absence of a lesion (Fleiss kappa : 0.00-0.34; Gwet's AC1: 0.12-0.83), although a higher agreement was observed when combining all lesions in the pyloric area (Fleiss kappa : 0.09-0.12; Gwet's AC1: 0.43-0.93). For the fundic area, a poor to very good agreement was also observed (Fleiss kappa : 0.17-0.70; Gwet's AC1: 0.90-0.97). Regarding the inter-rater agreement for the number of lesions, a poor to moderate agreement was found (ICC: 0.11-0.73). When using the scoring system developed in the European Welfare Quality Protocol, a poor single random rater agreement (ICC: 0.42; 95% CI: 0.31-0.56) but acceptable average random rater agreement (ICC: 0.75; 95% CI: 0.64-0.83) was determined. Microscopic scar lesions were often mistaken as ulcers macroscopically. These results show that the scoring of abomasal lesions is challenging and highlight the need for a reliable scoring system. A fast, simple, and reliable scoring system would allow for large scale studies which investigate possible risk factors and hopefully help to prevent these lesions, which can compromise veal calves' health and welfare.

Automated summary

The study aimed to determine the inter-rater reliability of scoring systems used to detect abomasal lesions in veal calves, comparing macroscopic and histological lesions. Various scoring systems were used to assess 76 abomasa retrieved from veal calves, with lesions classified into erosions, ulcers, and scars. The results showed a variable agreement among raters for the presence or absence of a lesion, with better agreement observed when lesions were combined within certain areas. Poor to moderate agreement was found for the number of lesions. The study highlights the importance of developing a reliable scoring system to effectively assess abomasal lesions in veal calves.