HERITABILITIES OF TEAT CONFORMATION TRAITS AND THEIR RELATIONSHIPS WITH SOMATIC CELL COUNTS IN HOLSTEINS

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Abstract
Teat conformation characteristics were measured on 402 Holstein-Friesian cows in 18 dairy herds in western Quebec and eastern Ontario. The purpose of the study was to determine the effects of heridity on teat conformation traits as well as to examine phenotypic relationships between the traits and somatic cell count as a measure of udder health. Maximum likelihood estimates of heritabilities of teat conformation traits and cell count, transformed to a log scale, were low; usually less than 0.10. Exceptions were length of front teat (h2 = 0.44) and distance of udder to the floor (h2 = 0.41). Significantly higher cell counts were associated with teats that were long, wide, not plumb and bottle (as opposed to cylindrical or funnel) shaped. The most highly correlated trait with cell count was distance of udder to the floor (r = − 0.24). However, many of the significant gross relationships observed were jointly related with age of cow, and when the effects of age of cow at calving, stage of lactation and herd were removed, only length of rear teat and front and rear teat medial diameters had significant influences on cell count.