Implication of “smart” ear-tags material, shape, weight, and placement on calves’ ear injury and position

In recent years, technology advancements and miniaturisation of sensors have made it possible to develop management systems mounted on ear-tags but the development of these systems has not focussed specifically on younger calves, and has rarely documented the impact of device shape, size, and material on calf ear injury and position. The current paper documents the steps taken to develop a “smart” ear-tag, reporting these impacts. To achieve this, a series of bench tests (phase 1), expert assessments and four animal experiments were conducted. Selected from phase 1, five shapes were tested in phase 2 on five calves, and suitability for the intended purpose assessed, alongside maximum tag weight (8 calves) and anatomical placement of the tag (6 calves). Finally, a longer-term assessment was conducted using the best prototype attached to 14 calves (phase 3). The optimum tag was a 20 g coin-cell shaped female receiver tag, made of polycarbonate-acrylonitrile butadiene styrene (PC-ABS) and thermoplastic elastomer (TPE) mixed material, placed in the inner third of the ear, between the two auricular ridges. This specific shape and weight presented minimal ear-droop and the highest retention rate.