Discrepancies in Evaluating Farm Management Routines as Risk Factors of Raw Milk and Udder Hygiene in Selected Dairy Farms of Fars Province, Iran

Abstract

The management practices relevant to bulk tank milk quality were studied in 29 dairy farms of Fars Province, Iran. Farm management practices were obtained by completion of a questionnaire and direct observation. Bulk milk was evaluated by performing standard plate count (SPC), preliminary incubation count (PIC), laboratory pasteurization count (LPC), coliform count (CC), somatic cell count (SCC) and detection of the contagious mastitis agents. The farms were divided into low and high SPC groups (below and above 100,000 CFU/mL) based on Iranian standards. Comparisons of the laboratory results between groups were done using two independent samples t-test. The relationships between the laboratory results were studied by Pearson’s correlation coefficients, all after logarithmic transformation. Associations of managerial risk factors (obtained by the questionnaire and one time of observation) with laboratory results were investigated using two independent samples t-test. P-values <0.05 were considered as significant. Both low and high SPC farms had PIC, LPC, CC and SCC levels above the relevant intervention limits, although the low SPC group had lower PIC and CC levels (P<0.001) and numerically lower LPC and SCC levels (P>0.05). Strong correlations were detected between SPC and PIC, SPC and CC, and PIC and CC, but many of the well explained risk factors of undesired milk quality lacked any relation with high bacterial counts of raw milk. This could be due to the small number of the studied farms, almost similar faults in the farms, wrong answers of the employees to the questions and modification of the milking practices in the presence of an inspector. Infections with Staphylococcus aureus and Mycoplasma bovis could be potential problems in the studied farms, contributing to the elevation of SCC and/or SPC levels. Veterinary interventions could not be based on the questionnaire results. Direct and frequent observations of farm routines could be recommended.

References

1. Ahmadi, M., Razavi Rohani, S.M., Ayremlou, N., 2009. Evaluation of Streptococcus agalactiae detection by PCR in milk and its comparison to other microbiological methods. Iranian Journal of Microbiology 1, 28-31.
2. Bolourchi, M., Kasravi, R., Tabatabayi, A.H., Hovareshti. P., 2004. The effect of a mastitis control program on some udder health and milk quality indices in a large dairy herd in Tehran Province. Journal of the Faculty of Veterinary Medicine, University of Tehran 59, 115-124.
3. Bolourchi, M., Mokhber Dezfouli, M.R., Kasravi, R., Moghimi Esfandabadi, A., Hovareshti, P., 2008. An estimation of national average of milk somatic cell count and production losses due to subclinical mastitis in commercial dairy herds in Iran. Journal of Veterinary Research 63, 263-266.
4. Boss, R., Naskova, J., Steiner, A., Graber, H.U., 2011. Mastitis diagnostics: quantitative PCR for Staphylococcus aureus genotype B in bulk tank milk. Journal of Dairy Science 94, 128-137.
5. Bramley, A.J., McKinnon, C.H., Staker, R.T., Simpkin, D.L., 1984. The effect of udder infection on the bacterial flora of the bulk milk of ten dairies. Journal of Applied Bacteriology 57, 317-323.
6. Bramley, A.M, McKinnon, C.H., 1990. The microbiology of raw milk. In: Robinson R.K., (Ed.), Dairy Microbiology, Elsevier Science Publishers, London, pp 163-208.
7. Britten, A.M., Emerson, T., 1996. A bulk tank culturing program for monitoring milk quality and udder health. Proceedings of the 35th National Mastitis Council, 149-150.
8. Britten, A.M., 1998. Is Strep mastitis causing high bacteria counts in your bulk tank? Proceedings of the 37th National Mastitis Council, pp. 26-34.

9. Chambers, J.V., 2002. The microbiology of raw milk. In: Robinson, R.K. (Ed.), Dairy Microbiology Handbook. John Wiley & Sons Inc., New York, pp. 39-90.
10. Cousin, M.A., 1982. Presence and activity of psychrotrophic microorganisms in milk and dairy products: A review. Journal of Food Protection 45, 172-207.
11. Ellis, K.A., Innocent, G.T., Mihm, M., Cripps, P., McLean, W.G., Howard, C.V., Grove-White, D., 2007. Dairy cow cleanliness and milk quality on organic and conventional farms in the UK. Journal of Dairy Research 74, 302-310.
12. Elmoslemany, A.M., Keefe, G.P., Dohoo, I.R., Jayarao, B.M., 2009a. Risk factors for bacteriological quality of bulk tank milk in Prince Edward Island dairy herds. Part 1. Overall risk factors. Journal of Dairy Science 92, 2634-2643.
13. Elmoslemany, A.M., Keefe, G.P., Dohoo, I.R., Jayarao, B.M.,2009b. Risk factors for bacteriological quality of bulk tank milk in Prince Edward Island dairy herds. Part 2. Bacteria count specific risk factors. Journal of Dairy Science 92, 2644-2652.
14. Elmoslemany, A.M., Keefe, G.P., Dohoo, I.R., Wichtel, J.J., Stryhn, H., Dingwell, R.T., 2010. The association between bulk tank milk analysis for raw milk quality and on-farm management practices. Preventive Veterinary Medicine 95, 32-40.
15. Emerson, T., 1989. Bulk tank milk bacterial culturing-an aid to quality milk production. Proceedings of the 28th National Mastitis Council, Tampa, FL., National Mastitis Council, Madison (WI), 1989, pp. 49–53.
16. Erskine, R.J., 2001. Mastitis Control in Dairy Herds. In: Radostits, O.M. (Ed.), Herd Health: Food Animal Production Medicine 3rd Edn, Saunders, Philadelphia, pp 397-433.
17. Fenlon, D.R., Logue, D.N., Gunn, J., Wilson, J., 1995. A study of mastitis bacteria and herd management practices to identify their relationship to high somatic cell counts in bulk tank milk. British Veterinary Journal 151, 17- 25.
18. Feng, P., Weagant, S.D., Grant, M.A., Burkhardt, W., 2002. Enumeration of E. coli and the coliform bacteria. In: Bacteriological Analytical Manual. FDA, USA. URL http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm064948.htm. (Accessed at 25/12/2013)
19. Foddai, A., Idini, G., Fusco, M., Rosa, N., de la Fe, C., Zinellu, S., Corona, L., Tola, S., 2005. Rapid differential diagnosis of Mycoplasma agalactiae and Mycoplasma bovis based on a multiplex-PCR and a PCR-RFLP. Molecular and Cellular Probes 19, 207-212.
20. Galton, D.M., Petersson, L.G., Merrill, W.G., 1982. Effects of premilking udder preparation practices on bacterial counts in milk and on teats. Journal of Dairy Science 69, 260–266.
21. Godkin, M.A., Leslie, K.E., 1993. Culture of bulk tank as a screening test: A brief review. Canadian Veterinary Journal 34, 601–605.
22. Goldberg, J.J., Wildman, E.E., Pankey, J.W., Kunkel, J.R., Howard, D.B., Murphy, B.M., 1992. The influence of intensively managed rotational grazing, traditional continuous grazing, and confinement housing on bulk tank milk quality and udder health. Journal of Dairy Science 75, 96–104.
23. Jayarao, B.M., Wolfgang, D.R., 2003. Bulk tank milk analysis: A useful tool for improving milk quality and herd udder health. Veterinary Clinics of North America, Food Animal Practice 19, 75-92.
24. Jayarao, B.M., Pillai, S.R., Sawant, A.A., Wolfgang, D.R., Hegde, N.V., 2004. Guidelines for monitoring bulk tank milk somatic cell and bacterial counts. Journal of Dairy Science 87, 3561–3573.
25. Jeffrey, D.C., Wilson, J., 1987. Effect of mastitis-related bacteria on the total bacteria counts of bulk tank milk supplies. Journal of the Society of Dairy Technology 40, 23-26.
26. Hashemi, M., Shekarforoush, S.S., 2006. Microbial and chemical changes of raw milk in various stages of production in industrial dairy farms of Fars province. Journal of Veterinary Research 63, 221-227.
27. Hashemi, M., Shekarforoush, S.S., 2008. Microbial and chemical changes of raw milk in various stages of production in traditional dairy farms of Fars province. Iranian Veterinary Journal 3, 81-88.
28. Keeter, A., 1997. Udder health management in large dairy herd-maintaining control. Proceedings of the 36th National Mastitis Council, Tampa, FL., National Mastitis Council, Madison (WI), 1997, pp. 140-144.
29. Lee, K.H., Lee, J.W., Wang, S.W., Liu, L.Y., Lee, M.F., Chuang, S.T., Shy, Y.M., ChangWu, M.C., Chi, C.H., 2008. Development of a novel biochip for rapid multiplex detection of seven mastitis-causing pathogens in bovine milk samples. Journal of Veterinary Diagnostic Investigation 20, 463-471.
30. Maturin, L., Peeler, J.T., 2001. Aerobic plate count. In: Bacteriological Analytical Manual. FDA, USA. URL http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm063346.htm (Accessed at 25/12/2013)
31. Murphy, S.C., 1997. Raw milk bacteria tests: standard plate count, preliminary incubation count, lab, pasteurization count and coliform count—what do they mean for your farm? Proceedings of the Regional Meeting of the National Mastitis Council, Syracuse, NY.Madison (WI), National Mastitis Council, pp. 34–41.
32. Pankey, J.W., 1989. Premilking udder hygiene. Journal of Dairy Science 72, 1308–1312.
33. Reinemann, D.J., Wolters, G.M.V.H., Billon, P., Lind, O., Rasmussen, M.D., 2003. Review of practices for cleaning and sanitation of milking machines. In: Bulletin of 381 International Dairy Federation, Brussels, Belgium.
34. Reneau, J.K., Seykora, A.J., Heins, B.J., Endres, M.I., Farnsworth, R.J., Bey, R.F., 2005. Association between hygiene scores and somatic cell scores in dairy cattle. Journal of the American Veterinary Medical Association 227, 1297-1301.
35. Schreiner, D.A., Ruegg, P.L., 2003. Relationship between udder and leg hygiene scores and subclinical mastitis. Journal of Dairy Science 86, 3460-3465.
36. Smith, K.L., Todhunter, D.A., Schoenberger, P.S., 1985. Environmental mastitis: cause, prevalence, prevention. Journal of Dairy Science 68, 1531-1553.
37. Vissers, M.M.M., Driehuis, F., Giffel, M.C.T., Jong, P.D., Lankveld, J.M.G., 2007. Short communication: quantification of the transmission of microorganisms to milk via dirt attached to the exterior of teats. Journal of Dairy Science 90, 3579-3582.