Using Longitudinal Assessment on Extensively Managed Ewes to Quantify Welfare Compromise and Risks

Abstract

Simple SummarySheep managed extensively can be exposed to several welfare challenges during the year, and the risk of some diseases can increase in warmer and wetter seasons. In this study, the welfare of Merino ewes was examined over a calendar year. The welfare of these animals, kept on a single farm with consistent management, varied substantially. Overall, the largest number of ewes experienced compromise and risk to welfare at weaning, indicating that this was the most vulnerable time. The main welfare issues identified were under and over feeding, ewe mortality, lameness, ecto-parasites (flystrike) and mastitis, all of which could be improved by modifying management practices, such as improved nutritional management and monitoring and better tail docking procedures. Future research must consider that significant variation in the on-farm welfare of ewes occurs during a calendar year, which needs to be accounted for when conducting on-farm assessments.AbstractThis study examined variation in the welfare of extensively managed ewes and potential welfare risks. A total of 100 Merino ewes (aged 2–4 years) were individually identified and examined at three key stages: pregnancy, lactation and weaning. Eight animal-based welfare measures were used to assess welfare: flight distance, body condition score (BCS), fleece condition, skin lesions, tail length, dag score, lameness and mastitis. Data were analysed by ANOVA and McNemar’s statistics. Overall, the average BCS of the group was in agreement with industry recommendations. However, a number of animals were classified with inadequate condition (either too thin or too fat) across the three observation periods. The presence of heavy dags was greatest at mid-lactation (87%, P < 0.0001), lameness was greatest at weaning (14%, P = 0.01), clinical mastitis was 1% annually, and five ewes were lost from the study. Ewes had better health at mid-pregnancy compared to mid-lactation and weaning. The main welfare issues identified were under and over feeding, ewe mortality, lameness, ecto-parasites (flystrike) and mastitis, all of which have the potential to be reduced with improved management practices. Future welfare assessment programs must consider that significant variation in on-farm welfare will occur in extensively managed systems and this needs to be accounted for when evaluating farms.

Animal-Based Measures to Assess the Welfare of Extensively Managed Ewes

“…The validity of these measures reported in Munoz et al [19], plus their reliability and feasibility examined in this study indicate that these six animal-based measures; BCS, fleece condition, skin lesions, tail length, dag score and lameness are appropriate/recommended to include in welfare protocols for ewes managed extensively, particularly in Australia. When these measures are combined, they provide a snapshot of the current welfare status of ewes, as well as providing evidence of past or potential welfare risks.…”

“…This study is part of a longitudinal on-farm study that was performed in Victoria, Australia between July and December, 2015 [19]. This study was approved by the University of Melbourne ethics committee (ethical review number 1513562.1).…”

“…The measures selected were: Body condition score (BCS) [14,20,21,22], rumen fill [23,24], fleece cleanliness [10], fleece condition [10], skin lesions [10], tail length [25,26], dag score [16], foot-wall integrity [27,28,29], hoof overgrowth [27,28,29] and lameness [10]. They were considered valid on the basis that they have been shown to have validity in previous studies, further details are reported in Munoz et al [19]. The measures selected address main welfare concerns for sheep, covering freedom from hunger, pain, injury or disease.…”

Welfare Assessment on Pasture: A Review on Animal-Based Measures for Ruminants

“…Animal-based measures (ABMs) evaluated on small ruminants concerning the comfort principle. Fleece fleece condition score 0-2 sheep DA AUS [79,82] dag score score 0-5 sheep DA AUS [79,82] Mastitis physical inspection of the udder (presence of fibrosis, swelling, inflammation, abscesses) score 0-4 sheep DA AUS [82] Tail length tip of the vulva covered by the tail yes/no sheep DA AUS [79,82] Claw alterations foot-wall integrity score 0-3 sheep DA AUS [79] hoof overgrowth score 0-2 sheep DA AUS [79] contagious ovine digital dermatitis yes/no sheep DA GBR [76,77] footrot yes/no sheep DA GBR [76,77] Interdigital dermatitis yes/no sheep DA GBR [76,77] white line yes/no sheep DA GBR [76,77] overgrown claws yes/no sheep DA GBR [76,77] foot abscess yes/no sheep DA GBR [76] granuloma yes/no sheep DA GBR [76] interdigital hyperplasia yes/no sheep DA GBR [76] injury yes/no sheep DA GBR [76] joint infection yes/no sheep DA GBR [76] 1 direct assessment: DA; recording (audio and/or video): R; sensor: S.…”

“…Furthermore, for other ABMs, such as cleanliness [76,77,79,82], or health indicators (e.g., integument alterations, fleece conditions, or foot lesions [76,77,79,82]), the evaluation was carried out by assessors, and the animals had to be restrained in small holding pens to allow individual examination; for the evaluation of mastitis, restraining the animals in a crate was also required [82]. These operations were therefore time-consuming and probably induced some level of stress in animals that were not used to being handled due their extensive living conditions.…”