The investigation of milk yield, composition, quality, and fatty acids in Angora goats based on rangeland feeding conditions
The study aimed to survey milk yield, composition, some quality characteristics, and fatty acids in Angora goats fed at rangeland conditions. The traits investigated were examined for lactation number (LN; 1, 2, and 3+), lactation stage (LS; early, middle, and late), and milking time (MT; morning and evening). The daily milk yields were determined as 415.60±21.58, 496.73±17.39, and 533.60±18.14 g (P<0.001), and the lactation milk yields were defined as 71.57±4.35, 90.15±3.25, and 96.31±3.99 kg (P<0.001) in the goats with LN 1, 2, and 3+, respectively. Milk chemical composition (fat, protein, lactose, and dry matter) changed significantly (P<0.05, P<0.01, P<0.001) because of LN, LS, and MT. The milk pH values were not varied significantly by LN, however, varied by LS (P<0.001) and MT (P<0.01) importantly. While LN did not affect the milk color coordinates, the effects of LS on a* values (P<0.001) and MT on a* and b* values (P<0.001) were prominent. The majority of fatty acids did not differ significantly among LN but differed importantly (P<0.05, P<0.01, P<0.001) due to the LS. Almost half of the total fatty acids consisted of palmitic (C16:0) + oleic (C18:1) acids, and the mean SFA ratio was 70.954±0.365% during the entire lactation period. Fatty acids responsible for odor specific to goat milk have decreased in the late stage of lactation. The ratios of ω6/ω3 were below the limit value of four during the lactation period. The results revealed that the milk production traits of Angora goats based on rangeland feeding conditions were higher than the averages accepted for the breed, with the acceptable values for milk composition and quality characteristics. Fatty acid compositions varied throughout the lactation period, including an increase in SFA and a decrease in UFA.