Consumers are becoming more aware of the relationships between diet and health and this has increased consumer interest in the nutritional value of foods. This is impacting on the demand for foods which contain functional components that play important roles in health maintenance and disease prevention. Vitamin E, organically bound selenium and betacarotene are important antioxidant components of animal and human diets, and also unsaturated fatty acids and yeast and their roles in animal and human health and immune function are indispensable. The present review paper will discuss these nutrients in relation to antioxidant and health considerations and draw conclusions as to vitamin and mineral supplementation needs.

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Content: Results of production traits obtained from first calving cows and evaluation of the breeding value of bull sires of Simmental breed in Serbia. Data was analyzed using the method of least squares and for evaluation of bulls' breeding value mixed model of random sire effect (BLUP method). Based on obtained results it was established in statistical analysis that breeding region had highly significantly affected (P<0.01) the deviation of production traits from the general average. Considerable deviation from the general average was caused by the year and season of calving (P<0.05), and interaction of breeding region and calving season contributed to high variation in yield of milk and milk fat (P<0.01).

**Originalni nau ni rad-Original scientific paper Rad je finansiran od strane Ministarstva za nauku i zaštitu životne sredine, R. Srbije u okviru projekta TR-6858B Apstrakt: Ekonomi nost i uspeh u sto arskoj proizvodnji naj eš e zavise od više osobina. Iz tih razloga neophodno je vršiti takozvanu simultanu selekciju na nekoliko osobina. Fenotipska povezanost osobina u govedarstvu odnosi se na postojanje zajedni ke pozitivne ili negativne kovarijanse, koja nastaje kao rezultat delovanja genetskih i faktora spoljne sredine. Ovim istraživanjem je obuhva ena 3.461 kontrolisana prvotelka simentalske rase, sa laktacijama zaklju enim u toku jedne godine. Sve prvotelke su se nalazile na imanjima individualnih poljoprivrednih proizvo a a na podru ju Republike Srbije.U radu su ispitane fenotipske korelacije izme u slede ih osobina mle nosti i plodnosti: trajanje laktacije, prinos mleka, sadržaj mle ne masti, prinos mle ne masti, prinos 4% MKM, uzrast pri prvom telenju, trajanje servis perioda. Rezultati istraživanja fenotipskih korelacija dobijeni su koriš enjem mešovitih modela LSMLMW (Harvey, 1990). Ovaj metod omogu ava optimalno sagledavanje brojnih uticaja na ispitivane osobine (bikova-o eva, odgajiva kog podru ja, sezone telenja, godina telenja).

Interrelationships between circulating concentrations of the insulin-like growth factors (IGF-I and IGF-II) were investigated in 235 blood samples taken from 145 healthy beef or dairy calves, bulls and cows of different breeds and ages. Autoradiography of Western ligand blots indicated different IGF binding protein (IGFBP) profiles between sera from different categories of cattle. Each IGF radioimmunoassay was validated by determining the effects of IGFBPs, ligand and contraligand, as well as serial dilution and comparison with results obtained after molecular sieve chromatography in acid. In female cattle mean values for IGF-I varied from 5.1 nmol/l in postparturient Holstein cows to 18.5-20.5 nmol/l in growing beef heifers, while mean IGF-II concentrations ranged from 30.0 nmol/l in the cows to 14.7-15.7 nmol/l in the beef heifer calves. In male cattle mean serum IGF-I ranged widely from 8.2 nmol/l in 1-day-old Holstein calves to 67.4 nmol/l in 16-month-old Simmental-type bulls. Mean IGF-II concentrations decreased from 22.9 nmol/l in 1-day-old Holstein bull calves to 11.9 nmol/l in 12-month-old beef bulls. Thus, total molar IGF concentrations were fairly stable in female cattle (24.7-35.1 nmol/l) but extended from 27.3 nmol/l to 81.8 nmol/l in the male cattle. The tendency for a reciprocal relationship between serum concentrations of these growth factors was most obvious in the periparturient cows.