Dairy cow welfare in spring-calving, pasture-based systems

While pasture-based production is often believed to provide cows the best welfare due to its apparently more natural environment, there are still challenges to dairy cow welfare within this system. Even in spring-calving pasture-based systems, maintaining good animal welfare in dairy production is challenged by increased intensification. The three aims of this thesis were to conduct a welfare assessment of spring-calving, pasture-based dairy farms in Ireland and identify the current state of dairy cow welfare, to use the data collected through this welfare assessment to identify risk factors for welfare during both the grazing and housing periods, and to investigate the effects of increased grazing intensity on indicators of welfare.

To achieve the first two goals we conducted a welfare assessment, incorporating both grazing and housing periods, to over 100 farms throughout southern Ireland. Data were collected on seven animal-based welfare indicators: locomotion, body condition, ocular and nasal discharge, integument damage, tail injury, and avoidance response to human approach. Opportunities to improve welfare included identifying causes and prevention of tail injury, nasal discharge, integument damage and fearful avoidance response, as well as the continued reduction of lameness despite being relatively low in comparison to other systems. Performance benchmarks were also established for each indicator which reflect the top and bottom performing 20% of study farms. These benchmarks illustrate the wide variation between farms and provide a reference for farmers to compare their performance and motivate improvement.

Separate risk factor analyses were performed for each welfare indicator during both the grazing and housing periods. Analyses identified 14 unique risk factors associated with one or more welfare indicators for the grazing period. Multiple risk factors were related to the housing period, thus, it was concluded that carry-over effects of housing may persist into the grazing period. Housing period analyses identified 35 unique risk factors for welfare. A large number of risk factors associated with tail injury during housing suggests further study of the causes and prevention methods would contribute to improved welfare of dairy cows. Associations between recommended guidelines for housing features and greater negative welfare indicators suggests guidelines may benefit from regular re-evaluation to ensure facilities meet the welfare needs of cows during the housing period.

To achieve the final goal of this thesis, an experimental study was conducted to determine the effects of differing levels of increased grazing pressure, characterised by differing pasture allowances and stocking rates, on welfare indicators between the early and late grazing periods. Examined welfare indicators were locomotion score, hoof health, rumen fill, ocular and nasal discharge, and integument damage. Only minor treatment effects were found on welfare indicators, yet all indicators except rumen fill and locomotion score demonstrated significant improvements from early to late grazing.

Through this thesis we gained knowledge on the current state of welfare in spring-calving pasture-based farms in Ireland, and identified risk factors that will aid in guiding future research and on-farm recommendations to promote continued improvement of dairy cow welfare. We also concluded that cows were able to cope well with increased grazing pressure, and that regardless of treatment, more time on pasture led to improvements in welfare.