Abstract

This study reviews the use of slow intake urea supplementation (SIUS) mixed with probiotics on the profile of fatty acids, amino acids, cholesterol and antioxidant protection of milk from grazing cows. A herd of 60 Suisse cows (511 ± 12kg) in the middle of lactation, 20 were pasturing exclusively over a silvopastoral on star grass (Cynodon plectostachyus) and brachiaria (Brachiaria brizantha), browsing legumes without supplementation (SP). A second group of 20 cows (514 ±14kg) same grazing feeding, were provided with 3kg of SIUS, mixed with 1.5kg of lactobacilli per day as supplement (LAB). The third group of 20 milking cows (544 ±10kg) were supplemented with 6kg/d of a commercial concentrate (COM). Eight commercial milks were also sampled (CM). The milk from the three experimental treatments was weighed each week. Average production was 17kg/d for COM, of 14kg/d in SP and 16kg/d in LAB (P<0.05). The saturated fatty acids and unsaturated fatty acids showed differences in the three treatments (P<0.05). Polyunsaturated fatty acids, omega 3 and conjugated linoleic acid were 34%, 46% and 68% higher in SP, COM and LAB respectively. Results have demonstrated that grazing diverse green fresh forages improve milk quality due to the increase of unsaturated fatty acids. LAB allowed a decrease of biohydrogenation. LAB and SP provided the milk with highest amount of omega 3. In a second observations polyphenols were measured in milk from grazing animals (G) and from milk obtained from ruminants kept in Full Confinement (FC). Samples were analyzed using the superoxide anion test to determine the Degree of Antioxidant Protection (DAP), expressed as the molar ratio between antioxidant compounds and an oxidation target.

Keywords: Probiotic; Quality; Milk; Cows; Tropic; Antioxidants