​Discriminant Analysis to Characterize Mastitis Resistant and Susceptible Karan Fries Cows and Response Operating Characteristics Curve for Comparing Regression/ Discriminant Model

Background: The profitability in the dairy enterprises is strongly affected by udder health and, to a minor extent, by morphometry. The present study was conducted to differentiate mastitis susceptible and resistant animals based on udder and teat type traits infrequently exist. Methods: The study was undertaken in ICAR-NDRI, Karnal of Haryana. A discriminate model was applied to differentiate mastitis susceptible and resistant Karan Fries cows for the study. For meeting the objective; 123 Karan Fries cows were subjected to developing a reliable mathematical function/equation (discriminant functions) for the provision of maximum separation among the mastitis resistant and susceptible animals. The hypothesis was designed to know if these udder and type traits appeal to mastitis-resistant and susceptible animals. The hypothesis for testing the equality of covariance matrices was depicted as: H0: ∑1 = ∑2 Vrs H1: At least one pair of sigma’s ∑ is different. Result: The model included contributory factors such as fore udder length, central ligament, udder balance, shortest distance of floor from fore teat (SDFT), shortest distance of floor from rear teat (SDRT), fore udder attachment (FUA), teat direction, Rear legs rearview, Hock development, udder depth, and udder width constructed and was found to demonstrate 69.1 per cent accuracy with p less than 0.001 and the Karan Fries functions at group centroids are -0.169 and 0.443 respectively for mastitis resistant and mastitis infected animals. The model will facilitate 92.1 per cent of the cases to correctly classify for mastitis resistant animals and the remaining 7.9 per cent being misclassified into the mastitis group.