Page 58 - BCHNews-122023-Web

58 WC DAIRY NEWS  CHRISTMAS 2023
The effect of limited outdoor access frequencies on several hoof and leg metrics
The American Dairy Science Association held their annual conference in Ottawa this summer, and we are pleased to present three summaries of some of the many interesting presentations.
Lauren Engelking, Ph.D.
Lauren recently defended her PhD in dairy cattle nutrition and physiology at the University of Alberta. Lauren’s research assessed the interaction between nutrition, physiology, and behaviour in transition dairy cows, with an overarching focus on the role of inflammation in cows - both the harmful and beneficial sides of inflammation, and the extent to which we should interfere.
Presentation by Shabnaz Mokhtarnazif, a MSc student from McGill University.
The effect of limited outdoor access frequencies on gait score, hoof lesions and hoof surface temperature of non-clinically lame cows housed in a movement-restricted environment.
S. Mokhtarnazif1, E. Shepley2, A. Nejati1, G.M. Dallago3, and E. Vasseur1
1McGill University, 2University of Minnesota, 3Université du Québec à Montréal
Even 1 hour per week of outdoor pasture access may improve hoof health in tie- stall cows!
Research has demonstrated the benefits of providing dairy cows frequent outdoor access to pasture to allow increased socialization amongst cows, freedom of movement, and improved hoof health. However, researchers at McGill University, The University of Minnesota, and Université du Québec à Montréal, acknowledge that this is not always possible for producers due to weather, land, and labour constraints. Therefore, researchers wanted to assess how cow gait and hoof health would be affected by lower frequencies of outdoor access, which may be more feasible for producers to provide. This research was interested in assessing the impacts of outdoor pasture access in typical, non-clinically lame cows house in tie-stalls due to a lack of research in this area. As cows
were not clinically lame before the trial, it was hypothesized outdoor access would improve subclinical parameters, rather than clinical parameters.
To assess this, 36 cows from a tie-stall barn were enrolled in the study. Before the trial, all cows were assessed for a variety of clinical and subclinical hoof health and lameness parameters to determine “pre- trial” data, before cows had any access to outdoor pasture. Cow gait was evaluated for clinical signs through visual gait scoring, and for subclinical signs using 3D motion analysis. Pressure platforms were also utilized to assess subclinical signs by measuring pressure distribution and contact area of cows’ hooves. Clinical hoof health was assessed using visual assessment of clinical claw lesions, and subclinical hoof health was assessed using infrared thermography cameras that measured hoof coronary band temperature which can be a sign of hoof inflammation (often preceding visible clinical signs).
Cows were assigned to one of two treatments for five consecutive weeks:
1) one hour of outdoor access on one day/ week
2) one hour of outdoor access on three days/week (for a total of three hours/ week)
After five weeks of outdoor access, cows were evaluated for the same parameters previously described, to assess how outdoor pasture access affected “post- trial” hoof health and lameness. Cows were then evaluated an additional eight weeks later, when outdoor access was no longer provided, to determine carryover effects of the prior outdoor access on hoof health and lameness.
Results showed no statistically significant differences in clinical lameness signs from pre-trial to post-trial, for either of the treatment groups, although gait score was numerically decreased from pre- to post-trial for both treatment groups, and this reduction remained eight weeks after the trial. The lack in clinical lameness signs from pre- to post-trial was anticipated as cows were not clinically lame before the trial. Before the trial started, some cows showed claw hemorrhages (low severity), however, providing outdoor access showed no effect on the severity or prevalence of lesions, suggesting that cows can be provided low frequencies of outdoor
pasture access without increasing clinical lameness or claw lesion severity.
More interestingly, cows in both treatment groups had a significant decrease in coronary band temperature from pre-trial to post-trial, and this reduction in temperature (adjusted for ambient temp) persisted even eight weeks after the trial was completed. When cows experience inflammation of certain tissues, the temperature is increased in affected areas, such as the hooves. As this change in temperature is not apparent to the naked eye and can only be detected by technologies such as infrared thermography, this is considered a subclinical measure of hoof health, which typically precedes clinical signs of reduced hoof health or lameness, such as swelling or limping. Therefore, the reduction in coronary band temperature in cows represents a reduced hoof inflammation and improved clinical hoof health, which may reduce lameness incidence in the long run. When comparing one day vs. three days of outdoor access, there were no differences in either clinical or subclinical lameness parameters; however, while even short durations of outdoor access have benefits, other parameters showed improvements only in the 3d/week group.
Overall, providing outdoor pasture access to cows housed in tie-stalls at low frequencies does not appear to worsen cow claw lesions or gait. Conversely, providing even one hour per week of outdoor pasture access may improve subclinical hoof health, as indicated by reduced coronary band temperature, of non-clinically lame tie-stall cows, but it’s important to note that other research is showing more improvements with higher frequencies of outdoor access.
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