Investigating dairy cattle welfare in Iran : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Palmerston North, New Zealand

Abstract

Dairy cattle welfare has implications not only for the economic performance of individual farms but also for public perception of the dairy sector, both of which are critical to the long-term sustainability of the industry. Although intensive dairy farming practices were introduced in Iran in the 1940s, there remains a paucity of data concerning the welfare status of dairy cattle in the country. In response to this gap, the present study aimed to develop and implement a comprehensive welfare assessment protocol for use on intensive Iranian dairy farms, with the objective of generating baseline data to inform future welfare improvements and identify risk factors associated with tail damage, lameness, and injuries of the tarsus and carpus (hock and knee). The welfare assessment protocol was developed based on a comprehensive review of existing literature and the research team’s understanding of welfare issues on Iranian farms and comprised 11 animal-based, 16 resource-based and management-based, and 2 stockman-ship-related assessments, as well as 10 categories of farm records. This protocol was implemented across 62 intensive dairy farms located in five arid/semi-arid provinces of Iran. Sample size recommendations from the Welfare Quality protocol were applied to determine the minimum number of animals required for each animal-based measure, apart from locomotion scoring and tail damage scoring at parlor exit. For these measures, either the entire milking herd was assessed or all cows within the early lactation group (i.e., ≤150 days in milk) were included. Results showed a discrepancy regarding nutrition management on the farms with body condition score being well-managed (average of 0.5% lean and 0.2% obese cows) but an evident lack of feed and water trough space on 17 and 9 farms, respectively (n=62). Prevalence of lameness was 33% and higher than the global average of 21%, while hock and knee injuries were comparable to the high end of studies on housed dairy cattle (e.g., 41% cows with hock swelling). Prevalence of broken tails was the highest in the world and there was a significant lack of understanding of the scale of the problem within the farmers with median farmer estimation of broken tails being 2.0%. Hoof trimming was considered a routine procedure with 51/56 farms trimming the hooves ≥2 times a year, and it had the largest effect on both lameness and broken tails. Higher frequency of hoof trimming was associated with decreased lameness (e.g., OR 0.55 when trimming >2 times versus <2 times a year) but increased broken tails on the farms (OR 4.87 when trimming >2 times versus <2 times a year). Injuries of hock and knee were associated with a range of risk factors, with only farming system being shared between all lesions. This variation in the type of risk factors associated with the lesions indicates that their aetiologies may be distinct. Our findings highlight significant disparities in cow welfare between farms and demonstrate the need to move from broad assessments to a more in-depth welfare assessment on Iranian farms.