Somatic cell count

Vitamin E supplementation has been shown to have positive effects on milk quality in a conventional commercial dairy herd. Milk obtained from cows that received supplemental vitamin E had lower somatic cell counts and plasmin concentrations than corresponding values in milk obtained from control cows. The reduction in plasmin as a result of vitamin E supplementation is very beneficial to the dairy industry because plasmin reduces the cheese-yielding capacity of milk, affects the coagulating properties of milk and its overall ability to withstand processing during cheesemaking (Politis et al., 2004). 

Barbano D M, Rasmussen R R and Lynch J M (1991), Influence of milk somatic cell count and milk age on cheese yield , Journal of Dairy Science, 74, 369-388. 

Ma Y, Ryan C, Barbano D M, Galton D M, Rudan M A and Boor K J (2000), Effects of somatic cell count on quality and shelf-life of pasteurized milk fluid , Journal of Dairy Science, 83, 264-274. 

Politis I and Ng-Kwai-Hang K F (1988a), Effect of somatic cell counts and milk composition on cheese composition and coagulating properties of milk , Journal of Dairy Science, 71, 1711-1719. 

Renau J K, (1986), Effective use of dairy herd improvement somatic cell counts in mastitis control , Journal of Dairy Science, 69, 1708-1720. 

Sub-clinical mastitis, on the other hand, has no visible symptoms and can only be diagnosed with laboratory methods (Wendt et al., 1994) (see below). The diagnosis of sub-clinical mastitis depends on two parameters, the microbiological profile of sampled milk and the somatic cell count (Hamann and Fehlings, 2002). The different severity levels of mastitis and symptoms used in diagnosis are described in Table 11.3. 

Both clinical and sub-clinical mastitis are usually accompanied by an increase in the somatic cell count (SCC a measure of white blood cells (95%) such as macrophages, segmented neutrophil granulocytes or lymphocytes) in milk. SCCs above a certain level are an indication of immune-system activation and are used as an indicator of sub-clinical , latent or chronic udder infections/mastitis (Concha, 1986 Ostensson et al., 1988), which were shown to affect milk quality, composition and shelf life. Dairy companies therefore impose SCC thresholds or reduce payments to farmers if certain thresholds are exceeded (Hamann, 2001 Urech et al., 1999). 

Bartlett, P.C., Miller, G.Y., Anderson, C.R. and Kirk, J.H. (1990), Milk production and somatic cell count in Michigan dairy herds . Journal of Dairy Science, Oct, 2794-2800. 

Deluyker H.A., Van Oye, S.N. and Boucher, J.F. (2005). Factors affecting cure and somatic cell count after pirlimycin treatment of subclinical mastitis in lactating cows . Journal of Dairy Science, 88, 604-614... 

Hamann, J. (2001), Relationships between somatic cell count and milk composition, in Proceedings of the IDF World Summit, Auckland/New Zealand. 

Hamann, J. and Gyodi, P. (1994), Effects on milk yield, somatic cell count and milk conductivity of short-term, non-milking of lactating quarters of cows . Journal of Dairy Research, 61, 317-322. 

Harmon, R.J. (1994), Physiology of mastitis and factors affecting somatic cell counts . Journal of Dairy Science, 77, 2103-2112. 

Holmes, M.A., Cockcroft, P.D., Booth, C.E. and Heath, M.F. (2005), Controlled clinical trial of the effect of a homoeopathic nosode on the somatic cell counts in the milk of clinically normal dairy cows . Veterinary Record, 156, 565-567. 

Rainard, P, Ducelliez, M. and Poutrel, B. (1990), The contribution of mammary infections by coagulase-negative staphylococci to the herd bulk milk somatic cell count . Veterinary... 

Seymour, E.H., Jones, G.M. and McGilliard, M.L. (1989), Effectiveness of intramammary antibiotic therapy based on somatic cell count . Journal of Dairy Science, 72, 1057-1062. 

Timms, L.L. and Schultz, L.H. (1984), Mastitis therapy for cows with elevated somatic cell counts or clinical mastitis . Journal of Dairy Science, 67, 367-371. 

Wilson, D.J., Das, H.H., Gonzalez, R.N. and Sears, P.M. (1997), Association between management practices, dairy herd characteristics, and somatic cell count of bulk tank milk . Journal of the American Veterinary Medical Association, 210, 1499-1502. 

It is a possible index of mastitic infection although the level of LPO in milk increases on mastitic infection, it is not well correlated with somatic cell count. 

Specific conductivity continues to attract interest as a convenient, objective means of detecting mastitis at the subclinical level. Although somatic cell counts do correlate with specific conductivity, the cell counts appear to be more sensitive for mastitis detection (Kozanecki et al. 1982). Fernando et al. (1982) found that the ratio of specific conductivities of fore-and postmilking strippings was an effective index of mastitis due to the sharp rise in the conductivity of the postmilk from infected quarters. Introduction of a foreign body, sterile polyethylene, into the udder caused changes in somatic cell counts and conductivity similar to those of mastitis (Jaster et al. 1982). 

Proteolysis of casein may be substantial under certain conditions, such as late lactation and mastitic infections. Under these conditions, the number of somatic cells increases. The most noticeable effect of high somatic cell counts is loss of cheese yield. Everson (1984) identified a loss of 0.045 kg of cheese per 45.36 kg of milk for every 106/ml increase of somatic cell count. Somatic cell counts above 4 x 106/ml were also correlated with enhanced lipolysis and with an increased... 

Ali, A. E., Andrews, A. T. and Cheeseman, G. C. 1980C. Influence of elevated somatic cell count on casein distribution and cheesemaking. J. Dairy Res. 47, 393-400. 

Andrews, A. T. 1983B. Breakdown of caseins by proteinases in bovine milks with high somatic cell counts arising from mastitis or infusion with bacterial endotoxin. J. Dairy Res. 50, 57-66. 

Bachman, K.C., Hayen, M. J., Morse, D., Wilcox, C. J. 1988. Effect of pregnancy, milk yield, and somatic cell count on bovine milk fat hydrolysis. J. Dairy Sci. 71, 925-931. 

Fitz-Gerald, C.H., Deeth, H.C., Kitchen, B.J. 1981. The relationship between the levels of free fatty acids, lipoprotein lipase, carboxylesterase, A-acetyl-p-D-glucosaminidase, somatic cell count and other mastitis indices in bovine milk. J. Dairy Res. 48, 253-265. 

In setting withholding periods for AMDs in milk, regulatory authorities allow the assumption that milk from a treated cow will be admixed with milk from untreated animals that is, MRLs for milk are based on bulk tank concentrations, prompting the comment that the solution to pollution is dilution. This is not unreasonable, as the human consumption of milk from a single animal will be a relatively rare event, at least in developed countries. An increased somatic cell count (SCC) of bulk milk is an indicator of the prevalence of mastitis in a dairy herd. Such infections are widespread and are therefore widely and routinely treated by AMDs administered by intramammary infusion (most countries) or systemically (Scandinavian countries). Cases of peracute mastitis will almost always be treated systemically in all countries. There is an expectation that a non-compliant residue is more likely to occur in milk from herds with a high SCC. The US Pasteurized Milk... 

During intramammary infection, the somatic cell count (SCC) in mastitic milk increases, and the concentrations of plasma components, including bovine serum albumin (BSA) and immunoglobin, are higher in comparison to normal milk. Several components in mastitic milk are... 

Manifestations of zinc deficiency, responsive to zinc therapy, have been observed in growing and mature cattle in parts of Guyana, Greece, Australia and Scandinavia. As levels in the pasture herbage are apparently comparable with those of other areas, the deficiency is beheved to be conditioned by some factor in the herbage or general environment. In dairy cows, low dietary zinc concentrations are associated with high somatic cell counts in their milk. 

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