Non-esterified fatty acid (NEFA) testing is a management tool to ensure that parturient cows are on the right plane of nutrition. If NEFA levels are above normal, the cow is metabolizing adipose tissue more than she should in order to maintain her condition. In this case, she needs a better plane of nutrition. If NEFA levels are below normal, the plane of nutrition could be lowered appropriately.

The Colorado State University Diagnostic Lab now offers a NEFA test to veterinarians and nutritionists anywhere in the U.S., Canada and Mexico. The lab's phone number is: (970) 297-1281.

It is good to evaluate at least 10 percent to 20 percent of your dry cows in order to get an accurate representation of the dry pen. If 10 or more samples are run, the cost of the test is $8 per sample. If fewer than 10 samples are run, the cost will be $14 per sample.
Here are goal values:

  • Less than 0.32 mEq/L if the cow is more than two weeks away from calving.
  • Less than 0.40 mEq/L if the cow is two weeks to two days away from calving.
  • Serum NEFA concentrations of cows within two days of calving are usually high and difficult to interpret.
  • If more than 40 percent of the animals tested have elevated NEFA serum concentrations, it indicates a negative energy balance and excessive adipose metabolism.

NEFA testing gives dairy producers, nutritionists and veterinarians a tool to ensure that their cows are on an optimum plane of nutrition prior to calving. The cow's overall health will be improved and metabolic disease can be minimized as well by ensuring the cow's immune system is at the level needed to respond to disease.