Body condition score (BCS) is one of the most frequently discussed measurements to assess the nutrition status and subsequent reproductive potential of both individual animals and the overall herd. Rightfully so, as research data supports its use as a more accurate indicator of energy balance and, by extension, a predictor of postpartum interval and pregnancy rate. However, the inherent subjectivity of the measurement lends to common misunderstandings regarding not only how to properly assess BCS but also what changes in scores mean for supplemental feed needs and associated costs. The objective of this discussion is to review the fundamentals of the BCS system and how to properly score animals, with special attention directed toward why mid- to late-summer is a critical time for scoring fall calvers.
The BCS system was developed over many years, resulting from the work of multiple research trials at both public land-grant universities and USDA facilities, in which the body composition (i.e., percent fat and protein in the carcass) of beef cows was measured. Different numerical scaling systems have been proposed from this research, including both 1-5 (with a + or – with each numerical value) and 1-9 systems. While the current dairy cattle scoring system is on a 1-5 scale, the National Research Council implemented the 1-9 scale (with 1 being severely emaciated and 9 being extremely obese) in the 1996 and subsequent editions of the Nutrient Requirements of Beef Cattle publication.
In the BCS system, body fat percentages of 3.77, 7.54, 11.30, 15.07, 18.84, 22.61, 26.38, 30.15 and 33.91 for scores of 1-9, respectively, are assumed based on body composition data from the previously mentioned trials. While more moderate scores and body fat percentages are typically seen in production, it is important to note that, biologically, it is possible for animals to reach either extreme end of the composition spectrum, which we know increases the risk for a multitude of physiological and production issues. Data summarized to develop these percentages further indicate that each unit of condition score change equates to 75 pounds to 85 pounds of live bodyweight, depending on the age and weight of the animal. This is important because it allows for estimates in changes in BCS to be made from average daily gain (ADG) based on energy intake relative to energy needs of the animal. From a production standpoint, this is where the rubber meets the road because it enables the prediction of BCS changes to be made from the nutrition program of a cow herd at any point in the annual production cycle.
Within the BCS system, our goal is to estimate energy reserves as percent body fat through visual appraisal. A few key advantages of the BCS system are:
- It does not necessarily require handling or physically restraining an animal (although palpating an animal by hand can be helpful at times to aid in visual confirmation). Thus, it does not require special facilities or equipment to collect scores.
- It can be quickly and easily assessed, making it practical for production settings.
- It is an accepted and standardized system that producers, extension professionals, nutritionists, veterinarians and others can use to score animals on the same scale.
A disadvantage is that, due to inherent human subjectivity, inaccuracies both in assessing BCS and in interpreting what scores mean for potential production outcomes do occur and can be considerable. Regardless of the subjective nature, the visual BCS system has proved much more useful in aiding our understanding of beef cow nutrient requirements than bodyweight alone.
When evaluating visual characteristics of animals to determine body fat reserves, critical areas on a live animal include the brisket, spine, forerib and ribs, hooks and pins, and tailhead. These are the areas in which fat will be deposited last when energy intake is in excess of requirements or mobilized first to meet energy needs if the animal is in a negative plane of nutrition. Several good extension resources are available to assist in proper assessment, including the "Guide to Body Condition Scoring Beef Cows and Bulls" from Kansas State University Research and Extension. Key factors that can influence our assessment of BCS are age, hair coat length, stage of pregnancy and rumen fill. This is where combining visual assessment with hand palpation can be very effective in improving scoring accuracy, especially when working cattle at key times of the year (pre-calving, breeding and weaning) when aspects, such as hair coat length and fill, are likely to influence appearance. Having a scorecard chuteside, which can be referenced at any time, can help greatly with training.
Nutrient requirements of the beef cow peak at early lactation, decrease toward weaning and increases again as pregnancy advances toward calving. It is important to keep in mind that nutrient intake from grazed and harvested forages almost always varies throughout the year. As a result, the cow is, typically, constantly either gaining or losing condition, making optimal management of BCS critical for reproductive success and minimizing costs.
Late summer is critical for assessing BCS on fall-calving cows because the last 60 to 90 days prior to calving represent the time that body condition can be economically added. A key benefit to fall calving is that cows are non-lactating while grazing during the growing season, so it is generally easier for cows to be in adequate BCS (minimum of 5 for mature cows and 6 for first-calf heifers) at the start of the calving season. However, a challenge with fall-calving cows is that condition can decline going into breeding if forage quality is declining as dormancy approaches. This problem can be exacerbated if cows are thin at calving. So, take time to closely evaluate condition of fall-calving cows now to ensure they are adequate at calving, which can help reduce supplemental feed needs later this fall.
