Data from the Norwegian progeny-testing program were used to examine the impact of milking characteristics and teat morphology on loge somatic cell counts (SCC) in first-lactation Norwegian Cattle. Three primary independent study variables (2-min milk, milk leakage and teat-end-to-floor distance) were evaluated in addition to six other study variables and six potential confounding variables. Seven different regression models were evaluated. Sire and herd were identified as confounding variables. The chosen model was based on 4090 cows in 1993 herds, sired by 119 bulls, and had a coefficient of variation of 0.59. Increased 2-min milk, decreased teat-end-to-floor distance and inverted or pointed teat-end shapes were significantly (P ≤ 0.01) associated with a higher loge SCC. Effect of herd was absorbed in the model and explained ∼ 50% of the total variability in loge SCC, whereas sire and the total effect the study variables explained < 5% each. Among-herd variability is discussed in relation to the study design.
ASJC Scopus subject areas
- Animal Science and Zoology