The effect of Seasonal heat stress on oxidants–antioxidants biomarkers, trace minerals and acute-phase response of peri-parturient Holstein Friesian cows supplemented with adequate minerals and vitamins with and without retained fetal membranes

Background The global warming has become a worldwide problem affecting adversely the human being and the productivity of the livestock. This study aimed to investigate the effect of seasonal heat stress on the incidence of retained fetal membranes, oxidant-antioxidant biomarkers, haptoglobin, mineral status, milk production, inseminations/conception, estradiol, and days open of Holstein Friesian cows raised under Egyptian environmental conditions. Blood samples were collected one week before parturition and one day after parturition from two dairy farms. Total proteins, albumin, nitric oxide (NO), glutathione reduced (GSH), haptoglobin, estradiol, calcium, phosphorus, iron, copper and zinc were measured in the blood serum for cows delivered during the hot months (May to September) and the cold months (December to April). Results Cows delivered during the hot months had the highest prevalence of retained placenta and were older ( P = 0.0001) of mean parity (4.93 ± 2.24), required more services/conception ( P = 0.0001; 3.14 ± 1.20), produced higher ( P = 0.0001) milk yield/Ton (8.43 ± 1.29) compared to those retained during the cold months (8.00 ± 1.03). All cows retained their placentae had low estradiol (( P = 0.0001) compared to those dropped their placenta within the same season. All cows retained their fetal membranes had high NO ( P = 0.0002) but low GSH ( P = 0.008), and globulin ( P = 0.041). During the hot months, cows with retained placenta obtained low calcium, corrected calcium and calcium/phosphorus ratio. The type of placental drop and its interaction with season influenced ( P