Fourty-Eight multiparous Holstein cows were randomly selected and enrolled 21 days before calving to determine the effect of feeding negative dietary anion-cation difference (DCAD) diet on prepartum and postpartum blood minerals, calf weight and milk production. Before the trial, all cows were fed a high-forage, low-energy diet. During the trial, cows were fed a diet formulated for late gestation (15CP, %35.7NDF, P % 0.5, and %1.2Ca) according to NRC, with a resulting DCAD (Na + K − Cl − S) of − 50mEq/ 100g of DM (negative DCAD). After calving, cows were fed a diet formulated for early lactation (%16.5CP, %32.4NDF, P %0.4) in feeding dairy cattle is a way to control the sudden decrease in serum Ca before and immediately after parturition, which is caused by rapid transport of large amounts of Ca into the mammary gland related to colostrgenesis. Blood and mid-stream urine samples were collected from 24 cows fed on DCAD ration and 24 cows fed on non DCAD ration daily starting 24h before calving (-1day), the day of parturition (0day), one day after parturition (+1), and second day after parturition (+ 2). Feeding DCAD ration lead to decreased urine pH and urine creatinine, but increase Ca urine execration in the DCAD group. However, the DCAD group showed a significant increase (P<0.05) in Ca, Mg, P, K, Cl, and Na concentration pre and post calving, compared to non DCAD group. Before parturition, feeding on DCAD ration caused a significant increase in urea and creatinine, but decreased bicarbonate compared to non DCAD group. While after parturition urea, creatinine, and bicarbonate were decreased in the DCAD group, compared to the non DCAD group. Milk production was increased for the DCAD group compared with non DCAD group, but no differences were observed in the milk component. In conclusion, feeding negative DCAD in the late gestation period improves the performance and productivity of dairy cows by increasing blood minerals and milk production.
Keywords | Acidogenic, Hypocalcemia, Lactation, Calcium, Health status, Dietary anion-cation