Antioxidant biomarkers in the milk of early postpartum Aardi goats during winter

Milk concentration of thiobarbituric acid (TBARS), total antioxidant capacity (TAC), and superoxide dismutase (SOD) biomarkers; and the composition of milk from a local breed of Saudi goats (Aardi goats) were investigated during the first four weeks postpartum. Milk TBARS was significantly higher (p < 0.05) in the 2nd and 3rd weeks postpartum, compared to the 1st and 4th weeks, and it was the lowest in the 4th week. Milk TAC concentrations followed a similar trend as TBARS, and were the highest in the 3rd week postpartum and lowest in the 4th week. In contrast, SOD concentrations were the highest in the 4th week postpartum. Low milk SOD concentrations in the early postpartum period indicate lower reactive oxygen metabolites. Milk fat, lactose, total solid (TS), and total non-fat solids (SNF) decreased significantly (p < 0.05) during the four-week period, while milk protein remained approximately the same. These results provide novel information on the concentrations of TBARS, TAC, and SOD, and on the composition of milk from Aardi goats during the postpartum period. In addition, our data indicate that Aardi goats in our experiment had higher percent of milk fat, protein, and lactose when compared with those of other breeds or Aardi goats in other parts of the country. As such, we expect this study on local Aardi goats in Saudi Arabia to contribute to our understanding of this breed's ability to respond to stresses via biomarkers in milk and changes in milk composition.