Prevalence of and factors associated with hock, knee, and neck injuries on dairy cows in freestall housing in Canada

Injuries are a widespread problem in the dairy industry. The objective of this study was to determine the prevalence of and explore the animal-based and environmental factors associated with hock, knee, and neck injuries on dairy cows in freestall housing in Ontario and Alberta, Canada. Freestall dairy farms in the provinces of Ontario (n=40) and Alberta (n=50) were visited for cross-sectional data collection. A purposive sample of 40 lactating Holstein cows was selected for detailed observation on each farm. Cows were scored for hock, knee, and neck injuries on a 3- or 4-point scale, combining the attributes of hair loss, broken skin, and swelling and with a higher score indicating a more severe injury. The highest hock and highest knee score were used in the analysis. Animal-based and environmental measures were taken to explore which factors were associated with injury. Overall, the prevalence of cows with at least one hock, knee, and neck injury was 47, 24, and 9%, respectively. Lame cows had a greater odds of hock injury [odds ratio (OR)=1.46] than nonlame cows, whereas cows with fewer days in milk (DIM) had reduced odds of hock injury compared with those >120 DIM (OR=0.47, 0.64, and 0.81 for <50, 50-82, and 83-120 DIM, respectively). The odds of hock injury was lower on sand (OR=0.07) and concrete (OR=0.44) stall bases in comparison to mattresses. Conversely, the odds of knee injury was greater on concrete (OR=3.19) stall bases compared with mattresses. Cows in parity 1 (OR=0.45 and 0.27 for knee and neck injury, respectively) and 2 (OR=0.49 and 0.40 for knee and neck injury, respectively) had lower odds of knee and neck injury compared with cows in parity 4+. Low feed rail heights increased the odds of neck injury (OR=76.71 for rails between 128 and 140 cm and OR=43.82 for rails ≤128 cm). The odds of knee injury was greater on farms where any cows were observed slipping or falling when moving into the holding area for milking (OR=2.69) and lower on farms with rubber flooring in the alley along the feed bunk compared with bare concrete floors (OR=0.19). These results demonstrate that individual animal characteristics, as well as barn design and animal management, are associated with hock, knee, and neck injuries. These data can help to guide investigations into causes and prevention of injuries.