Recent research reinforced what was already known about lowering DCAD levels in prefresh diets, but also added some practical applications to producers’ toolboxes.
By Dr. Elliot Block, Research Fellow, Arm & Hammer Animal Nutrition
Lowering prepartum dietary cation-anion difference (DCAD) in the three weeks prior to calving to reduce postpartum metabolic disease is a tried and true strategy to help dairy cows successfully navigate the transition period.
Over and over, this nutritional solution has been shown to reduce incidence of retained placenta and hypocalcemia. These health challenges negatively impact postpartum feed intake and energy balance, and are two causes of expensive and significant reductions in reproduction and milk production when they occur.
However, in order to reduce social and nutrition stress from multiple pen moves and ration changes, some dairies need to lower DCAD levels longer than the traditional 21 days to take advantage of this nutritional management strategy. In addition, some dairies are unable to create multiple prefresh groups because of facility limitations, which can make a 21-day lower DCAD diet difficult to implement.
Research1 from the University of Minnesota published in the September Journal of Dairy Science shows that feeding lower DCAD diets for as long as 42 days has a positive effect on blood calcium status and milk production.
In the study, cows were fed one of three diets:
• A negative DCAD (−16 mEq/100 g of dry matter) for 21 days before calving
• A negative DCAD (−16 mEq/100 g of dry matter) for 42 days before calving
• A positive DCAD (+12 mEq/100 g of dry matter) for 42 days before calving
• Overall, cows in both groups fed the negative DCAD diet tended to have greater postpartum total blood calcium compared with cows fed the positive DCAD diet