Editor’s note: The following answer is provided by Donna M. Amaral-Phillips, extension professor in the Department of Animal Science at the University of Kentucky.
Q: How we can prevent early-lactation dairy cows from becoming "loser dairy cows?”
A: Successfully transitioning dairy cows back into the milking herd after the dry period is one of the most important pillars associated with well-performing and profitable dairy herds.
The success of these nutrition and management programs directly relates to the reproductive performance, milk production, and health of cows during this next lactation. Essentially, transition cow programs need to be designed and managed to result in cows eating well after calving and entering lactation with no or very minimal health- and metabolic-related issues, such as metritis, milk fever, ketosis, or fatty liver.
As dairy researchers learn more about this vital time frame, they have found that subclinical diseases have a substantial impact on future reproductive and production performance and health, may often go undetected, and may be the underlying cause of suboptimum performance in dairy herds…
Dairy cows that suffer from these issues, whether clinically or subclinically, often are prematurely culled, and in Denmark, these cows are part of the complex that the Danes refer to as “loser cows.” The question we want to consider is how we can prevent early-lactation dairy cows from becoming "loser dairy cows.”
Prevent excessive body condition
Transition cows that are over-conditioned (body condition scores are equal to or greater than 4.0) eat less before and after calving, with feed intake dropping sooner and to a greater extent before calving than optimally body conditioned pre-fresh cows. As a result, these cows mobilize body fat to a greater extent compared to cows where feed intake is not compromised as greatly before calving. This greater mobilization of body fat causes excessive fat to accumulate in the liver of these cows, which further compromises the liver’s ability to make glucose to support milk production. Thus, these cows have a higher likelihood of developing fatty liver and then subclinical or clinical ketosis in addition to other metabolic disorders.
Feed intake of most cows decreases just before calving (generally less than 5 days before calving) which results in some mobilization of body fat. The key is the degree of mobilization of body fat. Over-conditioned cows and cows whose feed intake is excessively reduced before or just after calving mobilize more body fat (more than 0.5 body condition score by 30 days in milk) and consequently accumulate more fat in the liver. Thus, this increased mobilization of body fat results in a higher incidence of fatty liver and thus subclinical or clinical ketosis as evidenced by elevated ketones and non-esterified fatty acids (NEFA) in the blood pre- and post-calving.