Influence of some factors on somatic cell counts in cow milk

Abstract

In the review paper the effect of some factors on somatic cell counts (SCC) on the base of literature data are discussed. Several studies over the past 30 years have addressed issues surrounding SCC, their variation, and the potential use of SCC for monitoring milk quality. Clearly the major factor affecting SCC is a mammary gland infection and this holds true at the quarter, cow, or bulk tank level. Most studies suggest that cows with SCC less than 200,000 cells/ml are not likely to be infected with major mastitis pathogens, while cows with SCC of 300,000 or greater are very likely to be infected. Other factors such as lactation number, stage of lactation, and season of the year have only minor influences by comparison. Stresses of various types may aggravate the SCC level in a quarter which is already infected, but there is little evidence that any factor other than normal diurnal variation has a major influence on SCC in the absence of intramammary infection. An effective mastitis control program minimizes the opportunity to transmit infections from cow to cow, reduces stress upon the cow, teat and teat canal, and encourages maximal milk production.

U ovom preglednom radu razmatrani su, na osnovu literaturnih podataka, efekti pojedinih faktora na broj somatskih ćelija (BSĆ). Različita istraživanja u proteklih 30 godina odnose se na promenu BSĆ u mleku i mogućnost njihovog korišćenja za praćenje kvaliteta mleka. Poznato je da je infekcija mlečne žlezde glavni faktor koji utiče na BSĆ, i to na nivou četvrti, vimena krave i zbirnog mleka. Većina ispitivanja ukazuje da krave sa BSĆ ispod 200.000 ćelija/ml verovatno nisu inficirane glavnim uzročnicima mastitisa, za razliku od krava čiji je BSĆ 300.000 ili veći. Drugi faktori, kao što je broj, faza laktacije i sezona, imaju manji uticaj. Stres različitog tipa može pogoršati BSĆ već inficirane četvrti, ali malo je podataka da bilo koji faktor koji ne predstavlja normalne dnevne varijacije ima značajan uticaj na BSĆ u odsustvu intramamarne infekcije. Efikasan program kontrole mastitisa smanjuje mogućnost prenošenja infekcije s krave na kravu, smanjuje uticaj stresora na kravu, papile i sisni kanal i podstiče maksimalnu proizvodnju mleka.