Gas chromatography and IDF Standard method (1999) were used to analyze the fatty acid composition of milk fat of mares originating from the following breeds: 10 of Wielkopolska breed, 10 Konik Polski Horses, and 9 Polish Cold-blooded Horses. Eighty-seven mare's milk samples were collected in the years 2000-2002. Unsaturated fatty acids were shown to prevail in the milk fat of mares of Wielkopolska breed (61.32%) and of Konik Polski mares (52.58%) whereas saturated acids prevailed in the milk fat of Cold Blooded mares (54.95%). The study revealed that the fatty acid composition of the investigated groups of mares was breed-specific. Of course, the impact of other uncontrolled factors such as nutrition is not excluded, either.

Abstract. Analyses were carried out on the fatty acid composition of milk fat originating from mares of three breeds: Polish Cold-Blooded, Wielkopolski and Konik Polski. Milk was collected from mares in the early, mid and late lactation. Determination of fatty acids was conducted with the gas chromatography method. The analysis of the fatty acid composition demonstrated that over the entire lactation period unsaturated fatty acids (from 52.96 % to 62.46 %), represented mainly by linolenic (22.15 %) and oleic (19.98 %) acid, were predominantly present only in samples originating from mares of the Wielkopolski breed. In milk of mares of Konik Polski, saturated fatty acids appeared to predominate (51.95 % and 52.95 %) in the early and mid lactation, whereas unsaturated fatty acids (62.28 %) predominated in the late lactation. In the case of milk samples of the Polish Cold-Blooded mares, saturated fatty acids (represented mainly by palmitic acid) were observed to prevail in the early and late lactation (55.77 % and 61.31 %), whereas unsaturated fatty acids (52.20 %) were found to negligibly prevail in the mid lactation. The study confirmed that fatty acid composition was determined by the period of lactation and breed of the mares.