Editor's note: In the Nov. 20, 2009, edition of this newsletter, we reported on new research at Cornell University for identifying at-risk fresh cows. The cows are at risk for metabolic disorders, decreased reproductive performance and lower milk production. Here is an update on how that research is being applied out in the field:
A 1,000-cow dairy in western New York is reaping the benefits of a testing procedure for at-risk fresh cows.
"We see a reduction in DAs and the number of animals that need to be treated for metritis or other fresh-cow disorders," says veterinarian Michael Capel, of Perry, N.Y.
Each week, farm personnel or licensed veterinary technicians from Capel's clinic test the blood of healthy cows between three and nine days in milk, specifically looking for elevated B-hydroxybutyrate levels above 12 to 13 milligrams per deciliter. Cows that exceed that level have subclinical ketosis and are at risk for other problems. Once the cows are identified, the farm treats them for four days with propylene glycol and B vitamins. It has made a big difference in the cows' outcome.
This procedure can be used at both the herd level and the individual cow level, says Daryl Nydam, assistant professor of ambulatory and production medicine at the Cornell University College of Veterinary Medicine. Herd screening can be accomplished by taking blood samples from a representative number of fresh cows. Irrespective of herd size, you want to test a minimum of 12 cows that are three to 14 days in milk, Nydam says. Fifteen cows or more is even better. If 15 percent or more of those animals have elevated non-esterified fatty acid (NEFA) levels or elevated B-hydroxybutyrate (BHB) levels, it is a red flag. Again, a BHB level above 12 mg/dL is considered too high; for NEFAs, it is greater than or equal to 0.6 milliequivalents per liter in postpartum animals. When at-risk animals are identified and the proper intervention strategies are employed, like the New York dairy mentioned above, the cows make about 3 pounds more milk per day in the first 30 days of milk, Nydam says. And, their risk of developing DAs is cut in half, as is their overall risk of being culled from the herd, he adds. If you know that a number of cows are freshening with elevated NEFA or BHB levels, you can make the appropriate management changes. Perhaps the farm needs to make improvements in stocking density or cut down on the number of pen moves the animals are making.
And, Nydam says he is a big believer in controlled energy diets for prepartum cows. "If you get (the controlled energy diets) right, you will have a much lower incidence of high NEFA and/or subclinical ketosis postpartum," he says.