title: Use of test day milk fat and milk protein to detect subclinical ketosis in dairy cattle in Ontario.
abstract: Serum beta-hydroxybutyrate (BHB) levels were determined for 1333 dairy cows in various stages of lactation and parity on 93 dairy farms in Ontario. The data were collected in a cross-sectional manner, as part of the 1992 Ontario Dairy Monitoring and Analysis Program. The median serum BHB was 536 mumol/L for all cows, with a range of 0 to 5801 mumol/L. When subclinical ketosis was defined as a serum BHB level of 1200 mumol/L or higher, the prevalence of ketosis for cows in early lactation (< 65 days in milk (DIM)) was 14.1%. Prevalences for mid lactation (65-149 DIM), late lactation (> 149 DIM), and dry cows were 5.3%, 3.2%, and 1.6%, respectively. The mean serum BHB was significantly higher in the early group compared with each of the other 3 groups (P < 0.05). There was a trend of increasing prevalence with increasing parity across all stages of lactation. Only the difference between the parity-1 group and the parity-4 and greater group was statistically significant (P < 0.05). Both test-day fat percent and test-day protein percent were significantly associated with subclinical ketosis. However, test-day fat percent and test-day protein percent, used alone or in combination, were not useful screening tests for identifying cows with subclinical ketosis.
authors.affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph.
authors.forename: T F
authors.initials: TF
authors.lastname: Duffield
authors.forename: D F
authors.initials: DF
authors.lastname: Kelton
authors.forename: K E
authors.initials: KE
authors.lastname: Leslie
authors.forename: K D
authors.initials: KD
authors.lastname: Lissemore
authors.forename: J H
authors.initials: JH
authors.lastname: Lumsden
mesh_terms: D020155:3-Hydroxybutyric Acid; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004041:Dietary Fats / Q000378:metabolism; D005260:Female; D006885:Hydroxybutyrates / Q000097:blood*; D007662:Ketosis / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000662:veterinary*; D007774:Lactation; D008894:Milk Proteins / Q000378:metabolism; D009864:Ontario / Q000453:epidemiology; D010298:Parity; D015995:Prevalence
chemical_list: D004041:Dietary Fats; D006885:Hydroxybutyrates; D008894:Milk Proteins; D020155:3-Hydroxybutyric Acid