Graduate Student Literature Review: The effect of housing systems on movement opportunity of dairy cows and the implications on cow health and comfort*

Intensification within the dairy industry has led to an increase in use of more restrictive indoor housing sys-tems (most commonly tiestalls and freestalls) and less use of the pasture-based housing systems used in past generations. These indoor housing systems are associ-ated with not only a higher level of restriction to cow movement, but also with a higher prevalence of lame-ness and cow comfort issues on farm, which negatively affects cow welfare, public perceptions, and producer profitability. In looking for solutions to these issues, several studies have investigated different housing and management options that are less restrictive and in-crease cow movement opportunity. We hypothesized that movement opportunity, briefly summarized as the level of locomotor activity a cow is able to express in her given environment as well as the ease with which said movement can be expressed, can have a direct, substantial effect on cow comfort as well as cow leg and hoof health. Lying behaviors, which serve as com-mon indicators of cow comfort, are affected not only by the ease of movement that comes with providing more movement opportunity within the lying environment, but also by the aforementioned improvements to leg health. This is particularly true regarding the ability to display different lying postures and to rise and lie down with ease. The complexity of the relationship between the different methods by which movement opportunity can be provided to dairy cows and the corresponding effects on outcome measures related to cow health and comfort is an area of research that warrants explora-tion. In this literature review, we sought to identify how level of movement opportunity, provided though differ- ent housing systems and management practices, affects cow hoof and leg, udder, and reproductive health, as well as the effects that it has on cow lying behaviors that are indicative of comfort.