Performance of Swedish claw trimmers regarding shape and dimensions of the trimmed claw

Objectives

The aim of the study was to describe the variation in shape and dimensions of the claw after trimming performed by professional Swedish claw trimmers.

Materials and methods

Fourteen professional and certified claw trimmers in Sweden were assessed during their everyday work of preventive claw trimming. For each participating claw trimmer, dimensions were measured of the hind feet on a minimum of eight trimmed cows in the same herd. The selected cows were mainly of Holstein breed and mainly in their first or second lactation. The cows were randomly selected but had to be free from any obvious claw horn lesion. The requirement not to have any claw horn lesion aimed to get a better idea of what the claw trimmer wanted to achieve with his or her routine trimming method and to enable comparisons within and between claw trimmers. The claws were photographed after trimming according to a set protocol. The claw measurements investigated were; toe length (dorsal wall) and toe angle (dorsal wall x ground surface) on lateral (outer) claws, height difference of the posterior part of the lateral (outer) and medial (inner) claw of the same foot, modelling width for both lateral and medial claws as well as sole thickness at the toe area of the lateral claw. and the toe length and toe angle were measured from the digital photos by image analysis using ImageJ Software 1.51j8 (National Institutes of Health, USA). The height difference of the posterior part of the wall between the lateral and medial claws and the width of the modelling were measured using a profile gauge. A portable ultrasound machine (Draminski, iScan2) was used to measure sole thickness in the toe area. The variation in claw shape and dimensions after trimming within cow, within claw trimmer and between claw trimmers were analysed by a residual (restricted) maximum likelihood method and were presented as variance components’ percentage of the total variance. The variance components’ estimation and descriptive statistics for different claw measurements were performed using Minitab software (version 19.2020.1). [...]