Abstract: Scientific knowledge about the predispositions of Bosnian native breeds of sheep (Dubska) for the production of milk and milk products until recently were quite sparse and very scarce. Therefore, the aim of this study was to investigate the biochemical indicators and serum minerals, for monitoring the nutritional status. Until now subject research did not include testing of the effect of biochemical parameters and hormonal status of the blood of sheep on the quality of milk and milk products. Persistence of this connection is justified by the fact that most of the ingredients of milk just derived from the blood. The main objective of this research was to explore metabolic parameters of sheep’s blood, and their relative importance on the quality and quantity of milk components. The study included a total of 127 sheep blood samples from two different areas (Livno and Travnik) in summer feeding period (July, August and September). The animals were marked with the appropriate number of ear tags on the basis of which we always took samples from the same animals through different periods. In sheep blood serum, the concentration of biochemical parameters (glucose, cholesterol, triglycerides, total protein, albumin, urea, AST, ALT, AP, GGT, LDH, calcium, phosphorus and magnesium) and metabolic hormones (triiodothyronine, thyroxine, and insulin cortisol), and samples of milk: milk parameters (milk fat, lactose and protein) as well as fatty acid composition of the milk. The concentrations of blood biochemical parameters were determined by spectrophotometry with automated analysis with ready-made package of slides. Concentrations of metabolic hormones (T3, T4, cortisol and insulin) in the serum were determined by ELISA method. The percentages of fat, protein and lactose in milk were determined by infrared spectrophotometry. Fatty acids in milk were determined by gas chromatography (GC). Our research showed hypoglicemia, mild hypoproteinemia and hypoalbuminemia probablly due to nutritional deificiencies during lactation period. Negative energy balance could be responsabile for changes found in the cholesterol concentration as well as in the activity of ALT, AST, GGT, LDH. Significant differences in milk fat and milk protein, as well as fatty acids composition were determined between localities and season sampling. In general, our results showed varriation of blood biochemistry and milk quality. Due to differencies in climate, botanical differences of soil and pasture these variations are considered to be acceptable. Statistical analysis was performed using the software package SPSS 15.00<span "=""> (for biochemical paramters and parameters of milk) and 21.00 (for metabolic hormones and fatty acid composition of the milk).
Keywords: Sheep, Serum, Biochemical Parameters, Hormones, Milk