Original scientific paper
Seasonal variations of milk production and quality of Mediterranean ewes in extremely warm weather conditions
2018, 19 (3) p. 629-647
Starting from the assumption that the climatic conditions determine the quantity and quality of available forage on the pastures which is the largest source of nutrients of meal of sheep reared in coastal and island of Croatia, the aim of this research was to determine the seasonal variations of milk production and quality of Pag and Istrian sheep during three consecutive years – lactations (2012 – 2014) with extremely hot weather conditions. Regular monthly milking controls (using the AT4 method) included 30 flocks of Pag sheep and 19 flocks of Istrian sheep. In total, 29674 daily test records were collected in Pag sheep, and in Istrian sheep 12304 daily test records including the daily milk yield, the chemical composition of milk (content of milk fat, protein, lactose and dry matter) and number of somatic cells in milk. Significant (P<0.001) effect of the year on the daily milk yield of Istrian sheep was found, while unexpectedly, the average daily milk yield of Pag sheep, although predominantly kept in semi-extensive production system, has been uneven between the studied years (P>0.05). Significant variations of the daily milk yield of Pag sheep (P<0.001) and Istrian sheep (P<0.01) due to the season were established, as well as significant (P<0.001) seasonal variations of the content of all analysed milk constituents of Pag and Istrian sheep. Significant (P<0.001) phenotypic correlations were found between the daily milk yield and contents of all analysed components of Pag and Istra sheep milk.