February 15, 2021 at 3:09 p.m.
Tom is a sharp dairyman, and I like listening to what he has to say because I always learn something. He was correct. This was a failure, and it was a failure by both his management and my veterinary clinic’s consulting efforts. It was a failure because cows do not get displaced abomasum out there in nature on their own. They need some sort of help. Help might be too little bunk space in the pre-fresh pen, or it might be cows that are too fat, or it might be too crowded of a fresh pen, or lots of other things. Of course, we do not know what a normal rate of displaced abomasum might be for cows running around in the woods and not giving much milk like wild animals, but I bet it would be really low.
Displaced abomasum is a production-related disease, meaning that increased production increases the risk of DA. However, high producing herds, with high levels of management, often have lower rates of DA than lower producing herds because of their management. This is one of the many paradoxes in animal health in production agriculture. Tom’s herd had an annual rate of 4%, which is calculated by dividing the number of DAs by the total number of calvings. In our practice area, this is too high and easily puts his herd in the top 25th percentile of DA rate. We expect an average of about 2%.
So, Tom is right. Though, it is probably unrealistic to consider every DA as a failure, at least in practical terms. Realistically, he has at least 2% too many. For a 1,000-cow dairy that calves about 1,000 animals per year, 2% excess would be about 20 excess DAs per year. Some high producing herds can achieve 1% regularly, so by those standards, a 1,000-cow dairy with a 4% rate has about 30 DAs too many annually.
Why should a dairyman care? If we assume an average DA costs $700 in treatment costs, lost milk and increased culling, the annual excess cost for a 1,000-cow farm is $14,000 to $21,000. This is real money for sure but is not significant on a 1,000-cow dairy. However, the incidence of displaced abomasum is one of those tip of the iceberg kind of things. Many, if not most, DA cows suffer from other metabolic diseases, such as retained placenta, metritis, ketosis, fatty liver disease and others, but there are usually many more cows that have one or more of these diseases that never seem to get a displaced abomasum. So the rate of DA on a dairy probably vastly underestimates the true incidence of metabolic disease, and thus the real cost to the dairy is much higher. Tom knows this, and that is why he cares. DAs are often the easiest metabolic disease to define and to measure.
The second point is that we only know this because Tom managed to record these events, and because we know what is normal and what is desired. Normal is determined by looking at a lot of data from other farms, but this kind of data is hard to find. Desired would be a different name for a goal, and we determine them by looking at lots of data from other farms too. However, we also have to look at the history of Tom’s farm because his historic rate will help determine what is possible to achieve in a reasonable amount of time. Perhaps his goal should be 2% displaced abomasum, for example, even though another farm consistently achieves 1%, because such a significant reduction might be too much to expect in a short amount of time.
Numbers matter. Dairy producers get paid in numbers. We have to know the numbers before we can try to solve problems and to do better. Veterinarians can help dairy producers manage those numbers by helping them determine what data to collect, how to collect the data, and how to analyze and monitor the data. Most dairy veterinarians today do some of the data analysis for dairies themselves and are willing to help. Failure is normal in any business. However, instead of accepting failure, we can and should manage it to our advantage.
Bennett is one of four dairy veterinarians at Northern Valley Dairy Production Medicine Center in Plainview, Minn. He also consults on dairy farms in other states. He and his wife, Pam, have four children. Jim can be reached at [email protected] with comments or questions.
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