| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 ANAFI, via Bergamo 292, 26100 Cremona, Italy and Animal Breeding and Genetics Group, Wageningen Institute of Animal Sciences, PO Box 338, 6700 AH, Wageningen, The Netherlands
2 Animal Breeding and Genetics Group, Wageningen Institute of Animal Sciences, PO Box 338, 6700 AH, Wageningen, The Netherlands
The aim of the paper was to estimate variance components for somatic cell scores for Italian Holsteins using data from three different areas of the country. A total of 2,202,804 first-parity test-day records, collected from 1990 to 1997 in three areas of Italy (Mantova, Milano, and Parmigiano cheese area), were available for study. The areas differ in herd size, feeding systems and especially in milk use. A minimum standard of quality is also required by some specific methods of cheese production, as for example from the Parmigiano Reggiano cheese chain. These reasons, taken together, affect the attention given to the quality of milk production in herds, and, therefore, to the sanitation levels.
A pedigree file was extracted from the national database of Holstein Friesian breed. For computational reasons, eight samples of the data were extracted per area. Variance components were estimated by sample using two different test-day repeatability models. The first model included fixed effects of herd-test date, days in milk (30-d intervals) and calving month, and random effects of permanent environment, additive genetic and residual error. Estimated heritabilities in the first model ranged from 0.06 to 0.09 and repeatabilities from 0.36 to 0.45. Only small differences were detected among areas. In the second model, a random sire x herd interaction effect was added. Including the sire x herd effect resulted in heritability estimates ranging between 0.05 and 0.08 and repeatabilities from 0.35 to 0.45. The analysis revealed that only a small fraction of the total variance (0.35 to 1.5%) could be explained by sire x herd interaction effect. Based on this research, it appears that parameter estimates for somatic cell count do not differ by region, and inclusion of a sire x herd interaction effect is unnecessary.
Key Words: somatic cell count • sire x herd interaction • Holstein Friesian
Submitted on November 22, 2000
Accepted on June 26, 2001
This article has been cited by other articles:
|
|
 |
|
  A. B. Samore, A. F. Groen, P. J. Boettcher, J. Jamrozik, F. Canavesi, and A. Bagnato Genetic Correlation Patterns Between Somatic Cell Score and Protein Yield in the Italian Holstein-Friesian Population J Dairy Sci, October 1, 2008; 91(10): 4013 - 4021. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. L. Muir, G. Kistemaker, J. Jamrozik, and F. Canavesi Genetic Parameters for a Multiple-Trait Multiple-Lactation Random Regression Test-Day Model in Italian Holsteins J Dairy Sci, March 1, 2007; 90(3): 1564 - 1574. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. P. L. Calus, L. L. G. Janss, and R. F. Veerkamp Genotype by Environment Interaction for Somatic Cell Score Across Bulk Milk Somatic Cell Count and Days in Milk J Dairy Sci, December 1, 2006; 89(12): 4846 - 4857. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Sewalem, F. Miglior, G. J. Kistemaker, and B. J. Van Doormaal Analysis of the relationship between somatic cell score and functional longevity in canadian dairy cattle. J Dairy Sci, September 1, 2006; 89(9): 3609 - 3614. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. P. L. Calus, J. J. Windig, and R. F. Veerkamp Associations Among Descriptors of Herd Management and Phenotypic and Genetic Levels of Health and Fertility J Dairy Sci, June 1, 2005; 88(6): 2178 - 2189. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
