A narrative review of factors affecting the welfare of dairy cows in larger Australasian pasture-based production systems

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On the basis of current growth trajectories, pasture-based dairies of the future are likely to be bigger, have higher stocking rates and feed more concentrate to cows. This review uses the five-domains framework to consider risks to the welfare of dairy cows in these larger intensified pasture-based production systems. The factors considered in this review can be broadly categorised as (1) emerging welfare risks that can be managed, (2) emerging welfare risks that require research to be managed, or (3) persisting and/or exacerbated welfare risks. First, large herds could be subject to welfare risks associated with more stock per labour unit, longer milking times and longer distances walked to and from the dairy. To counter this, the time that cows in large herds spend off pasture can be reduced by splitting the herd into several more manageable groups, and animal-monitoring technologies can help identify health challenges with a reduced stockperson to animal ratio. Cow body condition and productivity can be maintained at high stocking rates by improving pasture production and feeding a higher proportion of concentrate. The risk of ruminal acidosis may then be reduced by appropriate transition feeding regimes and rumen buffers. Second, ensuring social stability and reducing competition may become difficult as herd sizes increase and feeding becomes more intensive. The resulting variability in feed intake, increased agonistic behaviour and social stress present emerging risks to cow welfare. Research is needed to better understand the social behaviour of cows in large intensive pasture-based herds, and how the design of the pre-milking area, the feeding pad and pasture feeding regimes (i.e. quantity and timing of pasture allocation) can improve accessibility for more vulnerable animals. Finally, intensive pasture-based dairies of the future will continue to face welfare challenges relating to lameness, mastitis and cull-cow management, whereas risks due to environmental exposure may be exacerbated by the removal of shelterbelts to facilitate irrigation. These require continued efforts in research (e.g. ways of incorporating shelter into intensive grazing systems), development (e.g. pathway to market for aged beef) and extension (e.g. improved record keeping and benchmarking of lameness and mastitis).