The prevalence, severity, and location of bruising of surplus unweaned calves under commercial transport conditions in New Zealand

Aims: To characterise the prevalence, severity, and anatomical location of bruising in surplus unweaned calves following commercial transport to meat processing plants and to compare these findings with calves slaughtered on-farm prior to transport. Despite bruising being a recognised welfare concern, data describing its occurrence under commercial New Zealand conditions remain limited.Methods: In 2023, carcasses (n = 5,476) of unweaned calves were assessed at two meat processing plants in New Zealand, one in the North Island (MP1) and one in the South Island (MP2), and one New Zealand pet-food processor (PP1) where calves were slaughtered on-farm. All carcasses were scored by a single trained technician using a standardised protocol that classified bruises ≥ 1.5 cm in diameter by size and anatomical location.Results: Overall, 71% of transported calves had at least one bruise ≥ 1.5 cm in diameter. Calves slaughtered on-farm had markedly lower odds of bruising than transported calves (OR = 0.12; 95% CI = 0.08–0.16), and bruises were generally smaller, with only 4/71 > 5 cm in diameter. Stifle bruising was the most prevalent lesion in transported calves (70% of all carcasses at MP1; 68% at MP2). Among transported calves, the proportion of carcasses with multiple bruises (≥ 4 bruised locations) was lower at MP1 than MP2 (OR = 0.32; 95% CI = 0.19–0.55), indicating between-premises variation in handling or transport conditions.Conclusions and clinical relevance: The inclusion of an on-farm slaughter comparison group provides strong evidence that most bruising arises after calves leave the farm of origin. The high prevalence and consistent localisation of bruising, particularly at the stifle, suggest that transport-related factors such as flooring type, stocking density, and loading or unloading events contribute to traumatic injury in surplus calves. These findings highlight the need for targeted welfare interventions during calf transport, including the evaluation of practical mitigation strategies such as non-slip flooring and increased space allowance, to reduce bruising and improve welfare outcomes for surplus calves.