Not surprising, the low NEFA cows also had low ketones. The medium NEFA cows had higher ketones, but were below the threshold of subclinical ketosis. The high cows had high enough ketones to be considered subclinically ketotic (> 1.1 mg/dL) but by 14 days after calving their blood ketones had dropped below the subclinical ketosis risk.
The very high NEFA group had near clinical ketosis ketones that remained elevated on both 7 and 14 days after calving. The high and very high groups are clearly the cows that will give you the biggest return on your investment if you can identify those cows and effectively treat them for ketosis.
click image to zoomFigure 2. Total 305-day lactation milk yield (pounds of milk/305 days) for cows grouped based on their serum non-esterified fatty acids (NEFA) concentration seven days after calving. The other take home message is that the medium NEFA group is the safest group as they had a very low risk for ketosis but also produced a similar amount of milk (Figure 2) compared with the high and very high NEFA groups.
Our future studies will aim to develop practical on-farm methods to predict cows at risk for ketosis and to develop feeding and management strategies to consistently keep cows in the medium NEFA group.
For now, we recommend targeting a body condition score between 3.0 to 3.5 at dry-off, feeding a good quality low energy diet during the dry period, maintaining feed intake after calving with good feed bunk management and comfortable environments, and quickly addressing low blood calcium issues.