Based on Dr. Rich Erdman’s conference presentation
Summary by Kai Yuan, PhD
Dietary Anion Cation Difference (DCAD) is not only important for pre-fresh dry cows but also for lactating cows. Based on a total of 43 published articles, increasing dietary DCAD linearly increased dry matter and NDF digestibility, and milk fat percent and milk fat yield.
Dr. Rich Erdman, University of Maryland. DCAD: It’s not just for dry cows. 2017 Tri-State Dairy Nutrition Conference Proceedings.
Key Points:
- Every 100 mEq/kg increase in DCAD 0.1 percentage unit increase in milk fat percent and a 38 g/d increase in milk fat yield.
- Increasing DCAD from 0 to 500 mEq/kg of DM resulted in a 3.5% unit increase in DM digestibility and a 7.5% unit increase in NDF digestibility. One of the modes of action of DCAD is the increase in ruminal pH and NDF digestibility.
- The minimal DCAD for lactating cows is most likely about 300 mEq/kg of DM, and the decision to feed additional higher DCAD with depending on the cost of supplementation and the added value of the extra milk fat produced.
- Feeds like soybean meal, alfalfa haylage, barley, grass silages, and molasses are high K and also high DCAD. Corn silage is intermediate in DCAD content. Protein supplements such as DDGS and canola meal are intermediate in K content and are low DCAD feeds because of their high S content. Dietary buffers containing bicarbonate and carbonate salts of K and Na will increase DCAD.
- Potassium provided by QLF lactation supplements helps to increase dietary DCAD to support milk fat production in the warm summer months.