Success in the transition period is a good indicator of whole farm management. Over the past five years my research group at the University of Minnesota has been studying what we call "Adaptive Nutrition."
Additive nutrition is a nutrition and management strategy that aims to minimize the impact of change in metabolism associated with changes in the dairy cattle life-cycle. This concept can be applied to any animal management system, but we focus mostly on application of these principles towards transition dairy cows and nursery calves.
Specifically we are looking for feeding and management strategies that achieve a high level of cow milk production or calf growth with low risk of metabolic stress that can increase the risk of health disorders. For fresh cows, successful feeding strategies maintain energy intake, avoid metabolic stress, reduce negative health event risk and maintain liver health.
Key components include: maintaining a high level of feed intake pre-calving without over-feeding energy and gaining body condition score, and maintaining feed intake after calving to minimize body condition loss.
When cows lose body weight and body condition score rapidly after calving they are at greater risk for ketosis and fatty liver. Blood NEFA (non-esterified fatty acids) represent body fat mobilized from the cow's back, thighs, ribs, and abdomen.
Think of NEFA as dollars that are withdrawn from a savings account that now can be spent on the things you want to accomplish.
Blood NEFA are an important source of energy for the cow and may have some additional roles in altering metabolism that affect milk yield and immune function.
The majority of NEFA in the blood is metabolized in the liver to provide energy, ketones, or is stored in the liver as fat. We know that high producing cows have higher or stronger hormonal signals that allow them to be elite cows.
Some of those hormonal signals regulate the rate and extent of body fat mobilization. Although NEFA is a good thing, excessive NEFA can result in both ketosis and fatty liver.
How much NEFA is too much?
We recently took a look back over the past four years of studies at the University of Minnesota St. Paul dairy barn and tried to answer this question.
click image to zoomFigure 1. Blood ketones (BHBA) concentration of cows grouped by serum non-esterified fatty acids (NEFA) concentration seven days after calving. We arranged the cows into four groups based on their NEFA level; low, medium, high and very high (Figure 1), and then took a look at the ketones or beta-hydroxy butyrate (BHBA) from these groups of cows.