The most basic visual dairy cattle evaluation system is the five-point body condition score (BCS) scale. It is well-known and used commonly in the modern dairy industry. It may have been covered in an introduction to dairy science class in college where you were first shown pictures of cows to describe each score. Maybe it was in training material for a new dairy industry job where understanding body weight change during lactation was important for success. In any case, this approach to standardizing how we understand the ups and downs a dairy cow experiences in body fat content throughout its life has stood the test of time. The five-point system was put forth by Wildman, et al. from Virginia Tech and published in the Journal of Dairy Science around 1980.
Some people are a natural at this evaluation and can rattle off scores for cows as they walk past them at a brisk pace. For others, it’s more of a contemplation process, looking for the exact right score for a particular cow. Either way, the goal is the same. We are trying to see if a cow has lost too much weight in early lactation or, conversely, gained too much weight in late lactation or during the dry period. This could be better accomplished with a set of body weight scales, but these are hard to find in any commercial dairy production system. Our friends who raise pigs or beef cattle would be surprised by how little we actually know about how much our cows weigh. We should be better.
Take a regular look
But with no hope of a common production approach to routinely weighing cows on most dairies, we will stick for now with the BCS system. It works but does lack some capabilities when dealing with large groups of cows. There is exciting technology already in use where cameras can capture images of cows in routinely travelled areas like a parlor exit to allow certain software to assign BCS. This approach has been around a while but has failed to gain traction. Having consultants and employees use the old standard of the 5-point BCS scale just seems easier all the way around. The problem for me is that I am honestly not that good at scoring cows. As opposed to the person who can score at a pen-walker’s pace, I am more the contemplative evaluator who gets stuck trying to figure out a quarter of a point difference when the rump doesn’t seem to agree with the brisket of an individual cow. Cows are like people; they don’t always store excess calories in the same parts of the body.
Summer is a great time to hone your body scoring skills. With reduced intakes and greater metabolic stress from panting and excessive standing time, energy balance can easily tip the wrong way and cows can get skinny fast. Every dairy should have a routine body weight analysis system that can provide a somewhat objective opinion on how the herd is doing. When such a program is ongoing and concerns arise, the data can be reviewed to see if there is in fact a change in the normal trend and concern is justified. After a management team agrees a problem is real, then ration adjustments can be made to address the issue.
Multiple applications
Using BCS averages for a pen or stage of lactation basis is workable but also a bit difficult. Since cows don’t react the same way to various inputs that can impact body weight change, a wide range of BCS results can contribute to the average. In such a case, is the BCS average truly a good metric informing a systematic management response?
I tend to think instead of what percent of a group falls out of the expected BCS range and use that information as a decision driver. In other words, I use a metric such as “percent under a 2.5 BCS” in peak milk pens or “percent over a 3.5 BCS” in a late lactation pen where cows are pulled for dry-off. If these metrics are routinely tracked and recorded, deviations from the percent outliers can be a powerful tool to best understand the herd’s body weight change situation.
This approach of counting outliers or counting at-risk animals becomes an easily trackable metric over time. For example, if a peak milk pen usually has 15% of the cows under a 2.5 BCS and you start seeing this number creep up into the mid-twenties, there is something happening that needs to be addressed. It may be that a higher percentage of these cows experienced a difficult transition and need a little extra energy to get back in shape. Perhaps they are just milking hard and adjustments to increase energy density, dry matter intake, or both may be the solution. If BCS can be improved, the result can be high peaks, nice lactation persistency, and cows that should be in adequate energy balance to become pregnant on time.
At the very minimum, every time you look at a group of cows or even replacement heifers, the body condition situation on the group should register automatically in your brain. It should be second nature. When thinking of the best way to do this, I suggest starting with a three-bucket strategy. Unless there are unusually wide variations in BCS like you might see in a set of purchased animals from a sale barn, the group BCS should easily fall into one of the buckets. Animals that are a little or very thin go in bucket number one. Bucket number two might be considered “about right.” The third bucket is labelled either trending heavy or already over conditioned. Understanding which bucket the group fits in will best inform the nutrition and management decisions that will follow.
No matter if you carefully score part or all of a group for entry into a spreadsheet, track percent outliers on a set schedule, or simply make a note of which of the three buckets above describe a set of cows, using the resulting information to help make nutrition and management decisions is good business. It would be better if we could weigh cows or use BCS cameras, but keeping it simple with the tried and true five-point BCS system can result in success.
Know your goals
There are several posters available from industry sources that might deserve a prominent place on the wall of the employee break room or dairy office. These posters should show the BCS goals for various stages of lactation, especially information about the specific farm’s goals for BCS at calving, the point of maximum weight loss in early lactation, and dry-off.
Each point move of BCS represents approximately 80 pounds of body weight. At first thought, this seems to be a small amount at only 5% to 6 % of a cow’s body weight. However, this is not what the points are meant to describe. The thought is more about setting a scale to describe the normal range of body weight change throughout a typical lactation and dry period. If an extreme weight loss situation for a fresh cow from calving to the lowest point of body weight before returning to a positive energy balance is 200 pounds, then the one point equaling 80 pounds represents 40% of that range. This is meaningful and allows for the trained eye to aptly estimate weight loss with the BCS change. This is a useful tool.
We may think the BCS system is old and maybe outdated with some higher-tech options now available. Yes, the system is old, but it’s not outdated. Training employees to score and depending on outside consultants to help will result in a better managed herd. This is a good example of the old adage, “If you measure it, you can manage it.” Summer is a great time to sharpen your team’s BCS skills. Having a routinely-tracked metric to help decide when the thinner cows of late summer have an actionable ration change situation is important.
We can argue if a 3.25 or 3.5 is the right score at dry-off and if 2.25 or 2.5 is an acceptable low score for cows in early lactation. We should, however, be able to agree on the fact that having a BCS scoring system in use at every dairy is good business. If you’d rather skip this step and buy a set of scales or a BCS camera for the exit alley, that would be even better — one can always hope!
