Alternative Somatic Cell Count Traits as Mastitis Indicators for Genetic Selection
- 1 June 2008
- journal article
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 91 (6), 2501-2511
- https://doi.org/10.3168/jds.2007-0459
Abstract
The aim of this study was to define alternative traits of somatic cell count (SCC) that can be used to decrease genetic susceptibility to clinical and subclinical mastitis (CM and SCM, respectively). Three kinds of SCC traits were evaluated: 1) lactation-averages of SCC, 2) traits derived from the proportion of test-day SCC above 150,000 cells/mL, and 3) patterns of peaks in SCC. Genetic parameters for these SCC traits and their genetic correlation with CM and SCM were estimated; CM and SCM were scored as binary traits. Two data sets (A and B) depending on CM recording were available. After editing, subset A contained 28,688 lactations from 21,673 cows in 394 herds. Subset B contained 56,726 lactations of 30,145 cows in 272 herds. Variance components for sire and permanent animal effects were estimated. Estimated heritabilities for all mastitis traits were around 0.03. Heritabilities for SCC traits ranged from 0.01 for patterns of peaks in SCC to 0.13 for lactation-average SCC. Genetic correlations between SCC traits and CM or SCM ranged from 0.55 to 0.93 for CM and from 0.55 to 0.98 for SCM. High genetic correlations were estimated between CM and SCC averaged over 250 d in milk (0.87), and between SCM and presence of test-day SCC >150,000 cells/mL (0.98) in subset A. In subset B, a high genetic correlation was estimated between CM and an SCC peak with a quick recovery (0.93) and between SCM and SCC averaged between 151 and 400 d (0.95). Partial genetic correlations were calculated to investigate the additional information of the alternative SCC traits, compared with lactation-average SCC. They showed that some traits remain informative for CM and others for SCM. Therefore, use of information from a combination of different SCC traits may be more successful in improving overall udder health than the traditional single SCC measure.Keywords
Funding Information
- Dutch Dairy Board
This publication has 24 references indexed in Scilit:
- Selection Indices in Holstein Cattle of Various CountriesJournal of Dairy Science, 2005
- Associations Between Pathogen-Specific Cases of Clinical Mastitis and Somatic Cell Count PatternsJournal of Dairy Science, 2004
- Genetic Analysis of Longitudinal Trajectory of Clinical Mastitis in First-Lactation Norwegian CattleJournal of Dairy Science, 2003
- International Genetic Evaluations of Holstein Sires for Milk Somatic Cell and Clinical MastitisJournal of Dairy Science, 2002
- The Effect of Pathogen-Specific Clinical Mastitis on the Lactation Curve for Somatic Cell CountJournal of Dairy Science, 2002
- Relationships Among Severity and Duration of Clinical Mastitis and Sire Transmitting Abilities for Somatic Cell Score, Udder Type Traits, Productive Life, and Protein YieldJournal of Dairy Science, 2002
- The effect of discontinuation of postmilking teat disinfection in low somatic cell count herds. II. Dynamics of intramammary infectionsVeterinary Quarterly, 1997
- Environmental MastitisVeterinary Clinics of North America: Food Animal Practice, 1993
- Contagious MastitisVeterinary Clinics of North America: Food Animal Practice, 1993
- Evaluation of changes in somatic cell counts as indicators of new intramammary infectionsPreventive Veterinary Medicine, 1991