By Choi, Y. S. and McDaniel, B. T., Journal of Dairy Science, 1993
Description
Genetic and phenotypic variations of hoof measurements were related to milk and fat yields, days open from calving to conception, and survival to various ages. Data were from 5551 measures in the first four lactations of 2972 Holstein cows in six herds over 15 yr. Estimates of heritabilities for hoof angles by multivariate REML averaged .18 but ranged from .03 to .39 by lactation. Similar averages for hoof lengths were .25 (range .08 to .53) and .07 (range .02 to .16) for heel depth. Hoof lengths had the highest phenotypic relationships with milk or fat yields and days open. Hoof angles of the first lactation were positively related to survival rates to various ages. For the second lactation, hoof lengths were the only useful predictors of survival. Days open, survival rate, and increase in age-adjusted milk yield from first to second lactation were favorably related to higher hoof angles and shorter hoof lengths. Within a lactation, higher angles and shorter lengths were undesirable for increased milk or fat yields. Genetic correlations of milk and fat yields with hoof angles were generally negative, but those for length were mostly positive. Genetically, days open decreased as hoof angle increased; some differences occurred among lactations. Longer hooves and deeper heels were positively related genetically to days open. Genetic correlations of hoof angles and heel depth with survival were positive, but those with hoof length tended to be negative
Genetic and phenotypic variations of hoof measurements were related to milk and fat yields, days open from calving to conception, and survival to various ages. Data were from 5551 measures in the first four lactations of 2972 Holstein cows in six herds over 15 yr. Estimates of heritabilities for hoof angles by multivariate REML averaged .18 but ranged from .03 to .39 by lactation. Similar averages for hoof lengths were .25 (range .08 to .53) and .07 (range .02 to .16) for heel depth. Hoof lengths had the highest phenotypic relationships with milk or fat yields and days open. Hoof angles of the first lactation were positively related to survival rates to various ages. For the second lactation, hoof lengths were the only useful predictors of survival. Days open, survival rate, and increase in age-adjusted milk yield from first to second lactation were favorably related to higher hoof angles and shorter hoof lengths. Within a lactation, higher angles and shorter lengths were undesirable for increased milk or fat yields. Genetic correlations of milk and fat yields with hoof angles were generally negative, but those for length were mostly positive. Genetically, days open decreased as hoof angle increased; some differences occurred among lactations. Longer hooves and deeper heels were positively related genetically to days open. Genetic correlations of hoof angles and heel depth with survival were positive, but those with hoof length tended to be negative
We welcome and encourage discussion of our linked research papers. Registered users can post their comments here. New users' comments are moderated, so please allow a while for them to be published.