cHoSEn PArAdoXES oF MAMMArY GLAnd FunctIon In coWS And rESuL tS oF MILK ProPErtIES

(1) In explaining some relations in physiology of milk creation and its composition and properties, logical dependences can be certainly found out, but along with them explanation paradoxes, too. Knowing them grains importance in the effort to keep a good state of health and concurrently to achieve high milk yield and quality. The stated is also a current topic of the present milk production. (2) Judging certain quality indicators of raw milk sometimes results in stating a paradox (sometimes apparent) deterioration of some quality indicators with improvement of the others. This possibility is given by the fact of numerous mutual links, dependences, and interference effects in multicomponent milk system in mammary gland lactogenesis. Sometimes the proper principles of dairy-analytical methods of measuring also contribute to the given effects. The correct milk quality interpretation presupposes knowledge of the substance of these phenomena. It often comes to antagonistic or apparently absurd findings in the link of health and composition milk indicators and physical properties as somatic cell count (SCC), urea concentration (U), milk freezing point depression (MFP), and fat content (F). (3) There is not such a shortage of real or apparent paradoxes in biology or physiology and pathology of livestock. An example can be given known as „mammary gland immunity paradox” mentioned by T a r g o w s k i (1985, quoted by H e j l i c e k et al., 1987). The thing is that it regularly comes to a markedly increased occurrence of new mastitis infections in cows essentially in the colostral period when the mammary gland is literally rich in antibodies for initiating passive immunity of the born calf. The said can be explained by creation of immunocomplexes arising in periods of increased permeability of the haematoalveolar barrier by antibody link to some protein components of mammary gland secretion (alfa-lactoglobulin, beta-lactalbumin and others). These immunocomplexes block the Fc receptors of phagocytes and so they decrease their phagocytar capacity very markedly. Obviously even leucotoxin secernated by mammary gland in the colostral period asserts itself. This toxin kills polymorphonuclears and cHoSEn PArAdoXES oF MAMMArY GLAnd FunctIon In coWS And rESuLtS oF MILK ProPErtIES*