Effect of the Dietary Cation-Anion Difference (DCAD) on performance and health in the transition phase of high-performing dairy cattle

One important health issue is (sub)clinical hypocalcaemia. In practice, several strategies are available to reduce the incidence of this health issue. In this study, a palatable source of anionic salts was used to achieve difference levels of close-up diet DCAD. Anionic salts may negatively impact dry matter intake (DMI) before and after calving. This study was carried out to study effects on periparturient DMI, incidence of (sub)clinical hypocalcaemia and subsequent lactation performance.

Experimental design

To evaluate the effect of DCAD in the close-up phase a feeding trial with 3 groups of 20 dairy cows was conducted.  Multiparous cows were allotted to one of the following treatments. A negative control diet similar to the far-off diet, without the use of anionic salts, resulting in a positive DCAD (High), a test diet with a moderate level of anionic salts, resulting in an intermediate DCAD (Medium), or a test diet with a high level of anionic salts, resulting in a negative DCAD (Low).

Diets were fed as PMR’s consisting of grass silage, maize silage, wheat straw, soybean meal, an additive and minerals, provided in troughs for individual feed intake measurements. Additional concentrates were fed in concentrate feeders and in the milking parlour. During the lactation period of 10 weeks, the same PMR diet and concentrates were fed to all cows.

Conclusions

From this study it is concluded that the level of Dietary Cation-Anion Balance (DCAB) in prepartum diets has a large influence on urine pH and Ca metabolism. Serum calcium levels improved at lower DCAB diet levels resulting in less incidence of clinical hypocalcaemia. But also the subclinical hypocalcaemia status improved around calving, due to a lower DCAB diet level prepartum. Dietary treatments prepartum had no effect on feed intake and milk production performance during the first ten weeks of the lactation period.