Ongoing research with dairy herds on the Herd Navigator milking system is providing Ontario Veterinary College (OVC) scientists with data on ketosis incidence and will help develop more effective treatment protocols.
Results from an on-farm clinical trial that started mid-June will provide researchers with data to make better treatment decisions for this condition, says Dr. Khaled Gohary, who is looking at patterns and impacts of ketosis to develop strategies for early response to this metabolic disorder.
Ketosis often occurs when dairy cows start lactating after calving if energy intake doesn’t meet their requirements. Cows with ketosis are at risk of developing other diseases, such as displaced abomasum and metritis which affect both health and productivity.
Herd Navigator measures key health indicators related to ketosis, mastitis, reproductive performance, and nutrition. The system can sample a cow’s milk during milking and uses a mathematical biomodel to generate risk scores for ketosis and to determine the frequency of testing and indicators that should be measured.
The Navigator system measures beta-hydroxybutyrate (BHBA) in milk to diagnose ketosis, says Gohary. “Based on this measurement, it sends an alarm if the cow measures above a certain threshold.”
Herd Navigator measures BHBA in milk daily for all cows in early lactation. During this clinical trial, funded by DeLaval-Canada, Mitacs and Ontario Ministry of Agriculture, Food and Rural Affairs, researchers are collecting and comparing data for two groups of cows with elevated ketone levels 3 to 37 days post-calving.
One group of cows are treated immediately when BHBA is elevated for one day based on Herd Navigator measurements and the other group includes cows that are treated when BHBA is elevated for two consecutive or two out of three days based on Herd Navigator measurements, says Gohary. Cows in both groups are treated with the same protocol (300 g of propylene glycol for five days).
Results of this clinical trial will offer insight into treatment. “If we start treatment earlier, is that intervention helpful to cows?” asks Gohary, who completed his DVM in Egypt and a herd health residency at University of California. He followed this up with a PhD in OVC’s Department of Population Medicine before starting a Mitacs Accelerate internship last year working with DeLaval Canada and the University of Guelph to study DeLaval’s Herd Navigator herd management system.
All cows between 31 to 37 days post-calving in the two trial groups are also tested for endometritis, an inflammation of the inner lining of the uterus which affects fertility, using Metricheck® to visually score vaginal secretions.
“We also collect milk production for 305 days, reproduction and disease incidence data to compare these outcomes between treatment groups,” adds Gohary.
The clinical trial will provide extensive data, says Dr. Stephen LeBlanc, Gohary’s supervisor in OVC’s Department of Population Medicine. “How often should you test for ketosis? If you test once a week you will catch a certain percentage of ketosis cases. If you test two times a week you will catch more. We will assess where the optimum balance of detection and labour efficiency lies”
Researchers also collect blood samples once per week on the farms they visit from each cow that is in the first five weeks after calving, whether they have elevated ketone levels on not, and measure BHBA in the samples cow-side with a held-held meter. Blood BHBA measurements will then be correlated to milk BHBA data collected on the same day by the farm’s Herd Navigator, says Gohary.
Herd Navigator is a relatively new technology, adds LeBlanc. While most dairy farmers don’t own a Navigator system, the information gleaned from this research is useful for non-owners as well. The results will refine recommendations for monitoring and treatment of ketosis in all herds.
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