At last week’s Dairy Cattle Reproductive Council meeting in Kansas City, Mo., Daryl Nydam, DVM, PhD, Cornell University, gave tips on sampling for non-esterified fatty acids (NEFAs) and β-hydroxybutyrate (BHB) to identify subclinical ketosis in dairy cows.

A lot of cow-level high NEFAs and BHBs increase the risk of culling in the post-partum period. However, measuring these value can give the producer an opportunity for cow-level management to decrease clinical disease, increase milk production and improve reproductive performance.

Which test should be used – NEFA or BHB – post-partum? It depends, said Nydam. The NEFA test is more accurate and does have a place if you really want to drill into the pre-partum issues, but it’s not rapid and it’s expensive, around $12 per sample. The BHBA test is between $1-2 per cow, but it can be done on-farm and in real-time.

“People will pay the higher costs for NEFA testing in troubleshooting situations, but it’s high for ongoing monitoring,” Nydam said.

When sending in samples
Nydam offers these recommendations for submitting NEFA and BHB samples for laboratory analysis:

  • Use a lab with validated tests
  • Red-top tubes are preferred for both BHB and NEFA
  • Keep the sample chilled and separate the serum ASAP
  • Plan to have the sample arrive at lab within 1-2 days
  • You can freeze serum for up to 1 month
  • You can get away with separating serum <24 hours and then sample in refrigerator for 3 days.

Read more about transition cow energy metabolite assessment from Cornell University here.