An attempt was made at identifying the activity of acid phosphatase (AcP) and beta-N-acetylhexosaminidase (Hex) in the whole raw milk of cows maintained on ecological farm and over the autumn/winter and spring/summer seasons (AW and SS season, respectively) fed with typical feeding rations. Both enzymes play a crucial role in animals' metabolism, affect the technological properties of milk and are indicators of homeostasis in animal tissues, including mastids. The effect of AW season was estimated on 23 while that of SS on 19 cows (yelding about 4200 kg milk per lactation), the latter being formerly included in search for the effect of AW season. Feeding was typical for each season: silages, hay, and concentrate in AW, and grass pasture, hay and concentrate in SS season. All the cows included were healthy and mastitis-free, and milk samples were obtained from each cow at the end of each season. The activity of both enzymes was found significantly lower in milk of cows at the end of AW than at the end of SS season. Since all the cows were found healthy and the difference could not be attributed to mastitis, it might be interpreted as an effect of seasonal feeding. It is suggested that the activity of both enzymes in milk of mastitis-free cows could be an indicator of efficiency of feeding system applied, and that the milk yielded during SS feeding is of higher cheese-making technological value for (e.g. Cheddar cheese production that requires dephosphorylation of protein) than that yielded during AW season. Further studies are needed to confirm our results.
