Association between somatic cell count in early lactation and culling of dairy heifers using cox frailty models

Journal of Dairy Science

Volumn 88, Issue 2, 2005, Pages 560-568

  De Vliegher, S ^a   Barkema, H W ^b   Opsomer, G ^a   De Kruif, A ^a   Duchateau, L ^a  

^a GHENT UNIVERSITY   (Belgium)

^b UNIVERSITY OF PRINCE EDWARD ISLAND   (Canada)

Author keywords

Cox frailty model; Culling; Dairy heifer; Early lactation somatic cell count

Indexed keywords

BOVINAE;

ANIMAL; ARTICLE; CATTLE; CELL COUNT; CYTOLOGY; DAIRYING; FEMALE; LACTATION; METHODOLOGY; MILK; PHYSIOLOGY; PROPORTIONAL HAZARDS MODEL; TIME;

ANIMALS; CATTLE; CELL COUNT; DAIRYING; FEMALE; LACTATION; MILK; PROPORTIONAL HAZARDS MODELS; TIME FACTORS;

EID: 15044361426     PISSN: 00220302     EISSN: None     Source Type: Journal    
DOI: 10.3168/jds.S0022-0302(05)72718-1     Document Type: Article

References (28)

1. Barkema, H. W., Y. H. Schukken, T. J. G. M. Lam, M. L. Beiboer, H. Wilmink, G. Benedictus, and A. Brand. 1998. Incidence of clinical mastitis in dairy herds grouped in three categories of bulk milk somatic cell counts. J. Dairy Sci. 81:411-419.
2. Barker, A. R., F. N. Schrick, M. J. Lewis, H. H. Dowlen, and S. P. Oliver. 1998. Influence of clinical mastitis during early lactation on reproductive performance of Jersey cows. J. Dairy Sci. 81:1285-1290.
3. Bascom, S. S., and A. J. Young. 1998. A summary of the reasons why farmers cull cows. J. Dairy Sci. 81:2299-2305.
4. Beaudeau, F., V. Ducrocq, C. Fourichon, and H. Seegers. 1995. Effect of disease on length of productive life of French Holstein dairy cows assessed by survival analysis. J. Dairy Sci. 78:103-117.
5. Coffey, E. M., W. E. Vinson, and R. E. Pearson. 1986. Somatic cell counts and infection rates for cows of varying somatic cell count in initial test of first lactation. J. Dairy Sci. 69:552-555.
6. Cox, D. R. 1972. Regression models and life-tables (with discussion). J. Royal Stat. Soc. B. 34:187-220.
7. De Vliegher, S., H. Laevens, G. Opsomer, E. De Mûelenaere, and A. de Kruif. 2001. Somatic cell counts in dairy heifers during early lactation. Flem. Vet. J. 70:212-215.
8. De Vliegher, S., H. W. Barkema, H. Stryhn, G. Opsomer, and A. de Kruif. 2004a. Impact in of early lactation somatic cell count in heifers on somatic cell counts over the first lactation. J. Dairy Sci. 87:3672-3682.
9. De Vliegher, S., H. W. Barkema, H. Stryhn, G. Opsomer, and A. de Kruif. 2005. Impact of early lactation somatic cell count in heifers on milk yield over the first lactation. J. Dairy Sci. (accepted).
10. De Vliegher, S., H. Laevens, H. W. Barkema, I. Dohoo, H. Stryhn, G. Opsomer, and A. de Kruif. 2004b. Management practices and heifer characteristics associated with early lactation somatic cell count of Belgian dairy heifers. J. Dairy Sci. 87:937-947.
11. Dohoo, I. R. 1993. An evaluation of the validity of individual cow somatic cell counts from cows in early lactation. Prev. Vet. Med. 16:103-110.
12. Duchateau, L., and P. Janssens. 2004. Penalized partial likelihood for frailties and smoothing splines in time to first insemination models for dairy cows. Biometrics 60:608-614.
13. Fox, L. K., S. T. Chester, J. W. Hallberg, S. C. Nickerson, J. W. Pankey, and L. D. Weaver. 1995. Survey of intramammary infections in dairy heifers at breeding age and first parturition. J. Dairy Sci. 78:1619-1628.
14. Freedman, L. S. 1982. Tables of the number of patients required in clinical trials using the logrank test. Stat. Med. 1:121-129.
15. Gröhn, Y. T., V. Ducrocq, and J. A. Hertl. 1997. Modeling the effect of a disease on culling: An illustration of the use of time-dependent covariates in survival analysis. J. Dairy Sci. 80:1755-1766.
16. Gröhn, Y. T., S. W. Eicker, V. Ducrocq, and J. A. Hertl. 1998. Effect of diseases on the culling of Holstein dairy cows in New York State. J. Dairy Sc. 81:966-978.
17. Laevens, H., H. Deluyker, Y. H. Schukken, L. De Meulemeester, R. Vandermeersch, E. De Mûelenaere, and A. de Kruif. 1997. Influence of parity and stage of lactation on the somatic cell count in bacteriologically negative cows. J. Dairy Sci. 80:3219-3226.
18. Neerhof, H. J., P. Madsen, V. P. Ducrocq, A. R. Vollema, J. Jensen, and I. R. Korsgaard. 2000. Relationship between mastitis and functional longevity in Danish Black and White dairy cattle estimated using survival analysis. J. Dairy Sci. 83:1064-1071.
19. Oliver, S. P., and B. M. Jayarao. 1997. Coagulase-negative staphylococcal intramammary infections in cows and heifers during the nonlactating and periparturient periods. J. Vet. Med. B. 44:355-363.
20. Oliver, S. P., and B. A. Mitchell. 1983. Intramammary infections in primigravid heifers near parturition. J. Dairy Sci. 66:1180-1183.
21. Rajala-Schultz, P. J., and Y. T. Gröhn. 1999a. Culling of dairy cows. Part I. Effects of diseases on culling in Finnish Ayrshire cows. Prev. Vet. Med. 41:195-208.
22. Rajala-Schultz, P. J., and Y. T. Gröhn. 1999b. Culling of dairy cows. Part III. Effects of diseases, pregnancy status and milk yield on culling in Finnish Ayrshire cows. Prev. Vet. Med. 41:295-309.
23. Roberson, J. R., L. K. Fox, D. D. Hancock, and C. C. Gay. 1994. Coagulase-positive staphylococcus intramammary infections in dairy heifers. J. Dairy Sci. 77:958-969.
24. Rupp, R., and D. Boichard. 2000. Relationship of early first lactation somatic cell count with risk of subsequent first clinical mastitis. Livest. Prod. Sci. 62:169-180.
25. Samoré, A. B., M. del P. Schneider, F. Canavesi, A. Bagnato, and A. F. Groen. 2003. Relationship between somatic cell count and functional longevity assessed using survival analysis in Italian Holstein-Friesian cows. Livest. Prod. Sci. 2003:211-220.
26. Schrick, F. N., M. E. Hockett, A. M. Saxton, M. J. Lewis, H. H. Dowlen, and S. P. Oliver. 2001. Influence of subclinical mastitis during early lactation on reproductive parameters. J. Dairy Sci. 84:1407-1412.
27. Seegers, H., F. Beaudeau, C. Fourichon, and N. Bareille. 1998. Reasons for culling in French Holstein cows. Prev. Vet. Med. 36:257-271
28. Waage, S., H. R. Skei, J. Rise, T. Rogdo, S. Sviland, and S. A. Ødegaard. 2000. Outcome of clinical mastitis in dairy heifers assessed by re-examination of cases 1 month after treatment. J. Dairy Sci. 83:70-76.