Lactoferrin, lysozyme and immunoglobulin G content in milk of four breeds of cows managed under intensive production system.

The aim of the study was to analyze chosen antibacterial protein content, i.e. immunoglobulin G, lactoferrin and lysozyme in bovine milk obtained from cows of four breeds raised and maintained under intensive production technology, that is in the free stall system, and fed total mixed ration diet (TMR system). The studies were conducted on milk from four breeds of dairy cows maintained in Poland, i.e. Polish Holstein-Friesian Black-White and Red-White variety, Jersey and Simental. Milk samples were collected solely from healthy cows, having performed the TOK test with Mastirapid. Further analyses were made only on the milk samples with SCC determined under 2.0 x 10(5) cells/ml, i.e. 423 samples. Each sample was examined for lactoferrin and lysozyme determination using reversed-phase high-performance liquid chromatography (RP-HPLC) with UV-VIS detector. The immunoglobulin G (IgG) levels were established by the aid of radial immunodiffusion technique with Bovine IgG LL tests (The Binding Site, Birmingham, UK). It should be stated that a breed of cow had a significant effect on a content of the antimicrobial proteins analyzed in bovine milk evaluated. Milk obtained from Simental and Jersey cows prove to be their excellent source, i.e. lactoferrin (116.74 and 103.48 mg/l), lysozyme (9.84 and 13.02 microg/l) and immunoglobulin G (579.9 and 508.6 mg/l). The highest content of these protein was stated in milk of multiparous cows at the late stage of lactation.