Effects of season on the quality of Garfagnina goat milk

The Garfagnina goat is an endangered native goat population from Italy. This study aims to give a contribution to the milk quality assessment of the native goat during the two productive seasons, spring and summer, and to verify the relationships between some meteorological data and physiological and milk quality parameters. Individual milk samples were taken in the two seasons. Physiological parameters and meteorological data were also registered. All the milk samples were measured for volume and analyzed for: dry matter, total nitrogen, casein, ash, lactose, fat, milk fatty acid composition, number and diameter of the fat globules, and rheological parameters. There were not differences in the average diameter of the milk fat globules (2.27 ± 0.28 μm) and in milk gross composition between the two seasons, except for lactose which was significantly lower in summer. During summer a significant increase in some long chain fatty acids such as CLA c9,t11, C18:1 t11, C18:0, C18:3 n3, C20:0, C22:0, C22:2 was observed, whereas short chain fatty acids (C6:0, C8:0, C10:0), which are responsible for the development of unpleasant aromas, as well as monounsaturated C16:1, C17:1 c9, C20:1, C22:1 and polyunsaturated fatty acids C20:2, C20:3 n3 decreased. The average PUFA n6/ PUFA n3 ratio was 1.7 and the lowest values were recorded in summer. In summer a worsening of the clot, which was less firm, was found. Environmental parameters were found to be linked to the milk fatty acids, while heart rate and skin temperature were negatively linked to milk yield and lactose respectively.