By: Jason Smith, University Of Tennessee, November 16, 2017 02:00 PM
Evaluating body condition has played a role in beef cow/calf systems for as long as they have existed – even long before the 1 to 9 scale was created. Nonetheless, it continues to be an important and impactful part of a cattlemen’s or cattlewoman’s tool belt. However it is a tool that is not used nearly as often as it should be. The universal method of evaluating body condition involves visually evaluating the animal, and assigning a body condition score (BCS) that reflects the animal’s current state of condition. This is a useful practice because an animal’s condition can be used as a fairly reliable indicator of its nutritional status. Thus, the BCS of an animal can be used as an aid when making certain management decisions, or can be used to determine that certain management interventions are necessary.
Because of its often forgotten value, I’m using this article as a reminder that now is a great time to evaluate body condition of your cowherd – that is, if you haven’t already done so. It is important that body condition be evaluated at times during the year that provide for the opportunity for any changes to be impactful. In an ideal situation, body condition is evaluated continuously throughout the year. However changing the nutritional status of an animal, at least to the extent that the change is visually evident, generally takes extended periods of time – think months. The two times throughout the year to formally evaluate body condition that seem to fit best in most common management programs are the spring and fall. This is because for most operations with a defined calving season, cows are either calving, or calves are being weaned during one of these two seasons. Thus, these concepts apply regardless of whether you operate a spring- or fall-calving herd, or even both, and specific timing can be modified to fit your management calendar.
Formally evaluating body condition around the time of each of these events (calving and weaning) allows you as a producer to make management decisions that will hopefully optimize that animal’s productivity. Doing so also allows you to evaluate, and if necessary, refine or replace that management decision in the future. At calving, the ideal BCS of a mature cow is 5 to 6. In low-input or extensive production scenarios, that will likely be unattainable. But for most of us in the mid-South, this is often achievable, assuming that the herd is not over-stocked. But, for our intent and purpose of providing cattle with the nutrients that they need to successfully reproduce once per year, it generally takes a BCS at calving of at least 5 to do that. This is because cows that calve below that threshold generally require extended periods of time to begin cycling again – to the extent that it places them outside the window of re-breeding within the 82 or so days necessary to calve once every calendar year (assuming a 283-day gestation length).
Replacement heifers should be managed to calve at one-half to one full BCS higher than the mature cowherd. This acts as a form of insurance for their fertility, and eases their transition into the normal rotation in the cowherd. For first-calf heifers (three-year olds), we could argue that the ideal BCS is similar to mature cows, however we know this is rarely achievable, as these females are still growing, and require roughly 10 to 15 % more energy and protein than the mature cowherd. Nonetheless, targeting a BCS at calving of 5 (with the understanding that many may only make it to 4 or 4.5) generally helps to maintain reproductive performance. Mature cows are also much more resilient to the negative effects of low BCS on reproduction than first-calf heifers.
At weaning, the ideal BCS for each category is much more difficult to define. Managing mature cows and first-calf heifers to maintain a BCS of at least a 4 at weaning generally yields good results for most producers. Generally that means that she had enough condition to prevent nutritional stress from causing abortion, and there is enough time remaining prior to calving that her condition can be increased. But maintaining that level of condition through weaning can be difficult for first-calf heifers, particularly those with a high level of milk production, and especially if the first-calvers are managed with the remainder of the herd. Thus, first-calvers will generally need to be managed separately and under a higher plane of nutrition than the mature cow in order to minimize the negative consequences of undernutrition.
As indicated by the previous example, body condition scoring is a valuable tool, but is only as valuable as we as managers allow it to be. What I mean by that is that knowing the BCS of a group of females doesn’t provide us any benefit if we don’t do anything with the information. The value of evaluating body condition lies in applying that information to management decisions. If BCS is less than ideal at calving or weaning, some nutritional management changes need to be made in order to ensure that reproduction and calf performance do not suffer. Depending upon the situation, this may require energy, protein, or a combination of energy and protein supplementation. Evaluating BCS, and reviewing BCS records over time will allow you to determine the magnitude of increase or decrease in BCS that you can expect over a given period of time under your standard management practices. If it appears that the current BCS of a herd or group is below that threshold, this serves as a good indicator that making a change in nutritional management is necessary to sustain productivity.