Structural characteristics of the bovine claw: horn growth and wear, horn hardness and claw conformation

Claw quality is the product of horn characteristics, claw shape and anatomy and physiology of the inner structure. This paper aims to review some of the different approaches that have been employed to evaluate claw quality. The various factors that may influence horn growth and wear are reviewed, including physiological, seasonal, nutritional, environmental, management and anatomical aspects. Horn hardness is similarly described. Claw conformation is discussed, commencing with a brief outline of the various methods used to determine claw shape and size, followed by an account of some of the factors that influence claw conformation. The clinical importance of claw conformation in cattle is considered with particular reference to lameness, longevity and production traits. Finally, the prospect of improving claw quality by selection of bulls based on claw measurements is reviewed.

Genetic and environmental variation of hoof characteristics of Holstein cattle

Genetic and environmental components of variation of hoof measurements were ascertained from 257 Holstein heifers and 1051 cows in eight herds in North Carolina. Angles and lengths of both claws, heel depth, and base area of the hoof were measured on both right feet for four herds. Angles, lengths, and heel depths were measured only on the right rear foot for four other herds. Heritabilities combined across all lactations were .30 or above but for individual lactations were as low as .12. Number of sires ranged from 16 to 40 for individual lactations. Average repeatabilities among measurements in same lactation were mostly above .40. Age affected all hoof measurements in heifers. Herd effects had a large impact on hoof measurements. Averages for hoof angles by ages ranged from 42 degrees to 45 degrees and from 60 to 70 mm for hoof length. Ratio of length to angle ranged from 1.36 to 1.68, heel depth from 34 to 44 mm, and base areas of hoof from 93 to 103 cm2. Lengths of medial and lateral claws for front and rear feet increased with advancing age. Medial front and lateral rear claws were longer than respective opposing claws.