Production loss due to new subclinical mastitis in Dutch dairy cows estimated with a test-day model

• Published in: Journal of dairy science Vol. 92; no. 2; pp. 599 - 606
• Main Authors: Halasa, T., Nielen, M., De Roos, A.P.W., Van Hoorne, R., de Jong, G., Lam, T.J.G.M., van Werven, T., Hogeveen, H.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.02.2009; Am Dairy Sci Assoc; Elsevier; American Dairy Science Association
• Subjects: Animal productions; Animals; Biological and medical sciences; Cattle; Dairying - methods; Environmental Monitoring; Fats - analysis; Female; Food industries; Fundamental and applied biological sciences. Psychology; Lactation; Mastitis, Bovine - physiopathology; Milk - chemistry; Milk - secretion; Milk and cheese industries. Ice creams; Milk Proteins - analysis; Models, Biological; Netherlands; new case; production loss; subclinical mastitis; Terrestrial animal productions; test-day model; Vertebrates; Netherlands; new case; test-day model; production loss; subclinical mastitis; Mastitis; Farming animal; Dairy cattle; Vertebrata; Mammalia; Dairy industry; Production; Models; Artiodactyla; Day; Ungulata
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2008-1564

Milk, fat, and protein loss due to a new subclinical mastitis case may be economically important, and the objective of this study was to estimate this loss. The loss was estimated based on test-day (TD) cow records collected over a 1-yr period from 400 randomly selected Dutch dairy herds. After exclusion of records from cows with clinical mastitis, the data set comprised 251,647 TD records from 43,462 lactations of 39,512 cows. The analysis was carried out using a random regression test-day modeling approach that predicts the cow production at each TD based on the actual production at all previous TD. The definition of new subclinical mastitis was based on the literature and assumed a new subclinical case if somatic cell count (SCC) was >100,000cells/mL after a TD with SCC <50,000cells/mL. A second data set was created by applying an adjustment to correct low SCC for the dilution effect when determining if the previous test-day SCC was <50,000cells/mL. Thereafter, the loss was estimated for records with SCC >100,000cells/mL. The production (milk, fat, or protein) losses were modeled as the difference between the actual and predicted production (milk, fat, or protein) at the TD of new subclinical mastitis, for 4,382 cow records, and 2,545 cow records after dilution correction. Primiparous cows were predicted to lose 0.31 (0.25–0.37) and 0.28 (0.20–0.35) kg of milk/d at an SCC of 200,000cells/mL, for unadjusted and adjusted low SCC, respectively. For the same SCC increase, multiparous cows were predicted to lose 0.58 (0.54–0.62) and 0.50 (0.44–0.56) kg of milk/d, respectively. Moreover, it was found that the greater the SCC increase above 100,000cells/mL, the greater the production losses. The estimated production losses were more precise than previously reported estimates.