What’s the issue?
- Potassium is a confusing mineral in regard to dairy cow requirements: during the dry period, dietary potassium needs to be restricted in order to reduce hypocalcemia risk post-calving, but during early lactation cows need to consume fairly large amounts of this mineral.
- During early lactation, especially during periods of heat stress, potassium needs to be supplemented in the ration in excess of current NRC (National Research Council) recommendations (currently set at 1.0% of ration dry matter).
What’s the impact?
- Cows that are potassium deficient during early lactation can experience an increased incidence of rumen acidosis, displaced abomasum, and in severe cases, become recumbent and experience muscle damage.
- Milk production can be reduced if cows are not provided enough potassium in their rations, especially during periods of heat stress.
- Feed a fresh cow ration containing at least 1.7% of ration dry matter as potassium and consider increasing lactating cow ration potassium levels even further during periods of heat stress.
- Treat cows with reduced feed intake (due to disease) with potassium-rich supplements.
- An effective way to determine if ration potassium levels are correct is by use of the dietary cation-anion difference (DCAD) concept. This is mainly used to influence calcium status pre-calving but also is helpful in preventing health issues post-calving.
Talk to your nutritionist regarding recommended levels of potassium in your rations and whether any adjustments are indicated. Talk to your local or ANIMART veterinarian about products that can help correct potassium deficiency in cows with reduced feed intake.
*Reference: Block, E. Make Sure Cows Get Enough Early Lactation Potassium, Progressive Dairyman, April 11, 2013.
Dr. Larry Judge
ANIMART Professional Services Veterinarian