The Impact of Dairy Resting Area on Hygiene, Lying Behavior, and Milk Quality
This thesis investigated the impact of dairy cow resting area on hygiene, lying behavior, and milk quality. The first cross-sectional study associated different bedding options (sand, straw, wood products, and recycled manure solids (RMS) and barn management practices with low bacterial count, improved cow hygiene, and milk quality. In that study it was demonstrated that elevated bacterial counts could be reported in any of the sampled used bedding types. At the cow level, factors associated with poor body hygiene for cows housed in free-stall barns were greater parity, while the opposite association was reported for cows housed in tie-stall barns. Regardless of housing system, cows in earlier stages of lactation were at higher risk of poor body hygiene when compared to later lactation cows. The second cross-sectional study aided in finding associations among barn management practices, lying behavior, and risk of elevated somatic cell count (eSCC). Lying duration was positively associated with deep-bedded stalls, negatively associated with cow body condition, and negatively associated with dirty stalls. Lameness prevalence was positively associated with dirty stalls. The last longitudinal, controlled study, investigated how the horizontal neck rail position in a free-stall was associated with stall cleanliness, cow hygiene, and the risk for intramamary infection (IMI) and lameness. Neck-rail position on the stall did not influence on SCC, nor in new cases of IMI. A greater percentage of cows had dirty udders when the neck-rail was positioned further from the stall during one of the treatment periods. Also, having a neck-rail positioned further from the curb tended to increase the risk for a new case of lameness in the second week of each treatment period. Finally, stalls were cleaner when bedding was added more frequently. Overall, this thesis provides evidence that bedding management can have a profound impact on cow milk quality, bacterial concentrations in the bedding substrates, and cow behavior, hygiene, and lameness risk.