Abstract
The relationship between test-day measures of milk somatic cell count and milk yield was evaluated using the November 1985 test data from 8352 Holstein cattle (2923 primiparous and 5429 multiparous cows) located in ten Tulare County, California dairies. Following correction for herd and stage of lactation effects, design variable regression was used to create separate models for primiparous and multiparous cows predicting the changes in milk production associated with milk somatic cell count class. Cell counts were stratified by 1/2 loge cell count (x1000 cells/mL) units, permitting comparisons with previous studies. Cell counts less than 148,000/mL were not found to be associated with significant reductions in milk yield when compared to the reference class (cell counts less than 20,000/mL). Consistent incremental decreases in milk production were not noted with increasing cell count strata, even following the natural log transformation. The most dramatic production losses were noted in the range of 148,000 to 665,000 cells/mL. Primiparous cattle in the 403,000 to 665,000 cell count strata experienced a 5.22 kg (19.72%) decrease in test-day milk yield. Multiparous cattle in the same class experienced 3.01 kg (7.82%) reductions in milk production. Primiparous and multiparous cows had similar production losses. The study population differed from previous studies on the basis of herd size, milk production and the level of udder health, measured by milk somatic cell count. These differences and the choice of experimental design may in part explain differences in study results and conclusions.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Dobbins C. N., Jr Mastitis losses. J Am Vet Med Assoc. 1977 May 15;170(10 Pt 2):1129–1132. [PubMed] [Google Scholar]
- Dohoo I. R., Meek A. H., Martin S. W., Barnum D. A. Use of total and differential somatic cell counts from composite milk samples to detect mastitis in individual cows. Can J Comp Med. 1981 Jan;45(1):8–14. [PMC free article] [PubMed] [Google Scholar]
- Dohoo I. R., Meek A. H., Martin S. W. Somatic cell counts in bovine milk: relationships to production and clinical episodes of mastitis. Can J Comp Med. 1984 Apr;48(2):130–135. [PMC free article] [PubMed] [Google Scholar]
- Forster T. L., Ashworth U. S., Luedecke L. O. Relationship between California Mastitis Test reaction and production and composition of milk from opposite quarters. J Dairy Sci. 1967 May;50(5):675–682. doi: 10.3168/jds.S0022-0302(67)87491-5. [DOI] [PubMed] [Google Scholar]
- Fox L. K., Shook G. E., Schultz L. H. Factors related to milk loss in quarters with low somatic cell counts. J Dairy Sci. 1985 Aug;68(8):2100–2107. doi: 10.3168/jds.S0022-0302(85)81074-2. [DOI] [PubMed] [Google Scholar]
- Janzen J. J. Economic losses resulting from mastitis. A review. J Dairy Sci. 1970 Sep;53(9):1151–1161. doi: 10.3168/jds.S0022-0302(70)86361-5. [DOI] [PubMed] [Google Scholar]
- Jones G. M., Pearson R. E., Clabaugh G. A., Heald C. W. Relationships between somatic cell counts and milk production. J Dairy Sci. 1984 Aug;67(8):1823–1831. doi: 10.3168/jds.S0022-0302(84)81510-6. [DOI] [PubMed] [Google Scholar]
- Kitchen B. J. Review of the progress of dairy science: bovine mastitis: milk compositional changes and related diagnostic tests. J Dairy Res. 1981 Feb;48(1):167–188. doi: 10.1017/s0022029900021580. [DOI] [PubMed] [Google Scholar]
- Meijering A., Jaartsveld F. H., Verstegen M. W., Tielen M. J. The cell count of milk in relation to milk yield. J Dairy Res. 1978 Feb;45(1):5–14. doi: 10.1017/s0022029900016137. [DOI] [PubMed] [Google Scholar]
- Pearson J. K., Greer D. O. Relationship between somatic cell counts and bacterial infections of the udder. Vet Rec. 1974 Sep 21;95(12):252–257. doi: 10.1136/vr.95.12.252. [DOI] [PubMed] [Google Scholar]
- Salsberg E., Meek A. H., Martin S. W. Somatic cell counts: associated factors and relationship to production. Can J Comp Med. 1984 Jul;48(3):251–257. [PMC free article] [PubMed] [Google Scholar]
- Schultz L. H. Somatic cell counting of milk in production testing programs as a mastitis control technique. J Am Vet Med Assoc. 1977 May 15;170(10 Pt 2):1244–1246. [PubMed] [Google Scholar]