Recording diseases by level of severity is often an inexact science. But failure to accurately record disease events and the severity of each case can play a huge role in how farmers manage disease incidence in their herds. For large herds, losses can approach six figures, especially if producers fail to record mastitis, retained placentas, ketosis, displaced abomasums or metritis.
Michael Overton, veterinarian and data analyst, Elanco Animal Health, analyzed a large herd that records metritis and classifies each case as either mild or severe. He examined the milk production, culling risk by 60 days in milk and the ability to get pregnant based on if cows had no metritis, mild or severe cases.
The herd averaged 26,931 lb. of milk on a mature-equivalent basis. Cows with no metritis produced 27,204 lb. per lactation. Those with mild metritis produced about 850 lb. less, and cows with severe metritis produced nearly 1,900 lb. less. Total milk loss in the herd from metritis was just under 900,000 lb. per year.
Based on $16.50 per cwt milk and 11¢ per pound of feed dry matter, the total milk loss due to metritis in the herd came to just over $110,000 per year. Overton created scenarios to mimic poor disease recording where mild cases of metritis were either under-reported or not reported at all. By under-reporting, the apparent incidence was much lower and the measurable milk losses based on the records would falsely suggest the loss was only about $61,000, or by not reporting mild cases at all, the apparent milk losses would appear to be only $21,000.
But that doesn’t mean metritis is not there, and the inaccurate records could lull the dairy into complacency about metritis prevention and treatment. Overton also looked at the risk ratio of getting cows pregnant by 250 days in milk and their culling odds by 300 days in milk based on whether they had zero, mild or severe metritis. The risk ratio for pregnancy of none versus mild was 1.23, none versus severe was 1.25, and mild versus severe, 1.02. The risk ratio for culling of none versus mild was 1.13, none versus severe was 1.77, and mild versus severe, 1.56.
Overton’s conclusion: “Misclassification of metritis underestimates the association between metritis and production, reproduction and culling risk. Improved definition and recording of metritis can lead to better understanding of the impact of metritis and other diseases on individual herds.”
Transition Cow Diseases Costly
Elanco’s veterinarian and data analyst Mike Overton analyzed nearly 156,000 first and greater lactation records from 27 herds in 12 states to estimate the costs of transition cow diseases: Mastitis, metritis, retained placentas (RP), metritis and RP, and displaced abomasums. The estimated losses, not including treatment costs, are for disease occurring in the first 30 days in milk and are based on milk and reproductive losses across lactation and culling by 60 days in milk. Milk losses from mastitis are substantial, approaching $200 for first-calf heifers and exceeding $250 for second and later lactation cows.
Note: This story ran in the March 2018 magazine issue of Dairy Herd Management.