Body Condition Scoring of Cows
Mark Z. Johnson, Oklahoma State University Extension Beef Cattle Breeding Specialist, David Lalman, Oklahoma State University, Daniel Stein, Oklahoma State University, Emily Free, Okmulgee County OSU Extension Agriculture Educator
The body condition scoring system (BCS) is used to assess body energy reserves in beef cows. The BCS system used for beef cattle ranges from 1 to 9. A score of 1 indicates cows that are thin and emaciated, while cows of BCS 9 are fat and obese. Thin cows should receive a lower score, and fat cows should receive a higher score.
When body condition scoring cows, producers should look beyond age, frame size, depth, length, pregnancy status, and hair coat. The body condition scoring system is intended to provide a consistent system to quantify relative fatness regardless of these other factors that create differences in a cow’s appearance. There is a strong relationship between weight and BCS. For each unit change in BCS, cows should gain or lose approximately 7% of their BCS 5 weight. For example, a cow that weighs 1,200 lbs. at a BCS 5 should reach a BCS of 6 at 1,284 lbs. or drop to a BCS 4 at 1,116 lbs.
Best Time to Evaluate BCS?
Typically, late summer/early fall (when cows are slicked off and in 2nd trimester of pregnancy) is the most accurate and easiest time of the management cycle to evaluate BCS on cows. Weaning time, or at time of fall pregnancy checks, is realistically the most convenient time of the annual management cycle to capture a weight on cows. Evaluating cows around weaning will allow for feeding and management strategies to be implemented, and adequate BCS to be reached by the start of calving season.
Why is BCS Important?
There is a close relationship between BCS at calving and the first 90 days after calving to reproductive success. In addition, cow body condition influences the calf’s ability to develop a strong immune system. One of the major constraints in the improvement of reproductive efficiency in cows is the length of post-partum anestrous. If cows are to maintain a calving interval of one year, they must bred back within 80 – 85 days after calving. In both old and young cows, it is well established that BCS at calving time determines the rebreeding performance of beef cows in the subsequent breeding season. Cows that maintain body weight should have ample energy reserves before parturition, and therefore, exhibit estrus sooner than cows losing weight.
Figure 2. Percent rebred at next breeding season per day, according to body condition at calving (summary of six trials in four states) BCS 4 or less, BCS 5, BCS 6 or more. Source: M.J. Field and R.S. Sand, Eds. Factors Affecting Calf Crop (1994). CRC Press, Inc., Boca Raton, FL.
Body weight change during pregnancy is confounded with fetus and placenta growth. Therefore, the estimation of body fat by use of BCS is a more useful tool (compared to weight change) in quantifying the energy reserves of beef cows. The process of fetal development, delivering a calf, milk production, and repair of the reproductive tract are all physiological stresses. These stresses require the availability and utilization of large quantities of energy to enable cows to rebreed within 85 days postpartum. Cold and/or wet weather is often faced by spring calving cows and adds additional environmental stress. This results in energy intake that may be below body maintenance needs. The cow compensates by mobilizing stored energy or adipose tissue, which is why adequate BCS at calving is so critical to reproductive performance.
The Goal
Producers should manage their calving season, genetics, grazing system, supplementation program, and herd health to achieve an average BCS of 5 to 6 (target 5.5) in the mature cow herd at calving time. The goal for first calf heifers is to have a BCS of 6 at calving. Subsequently, producers should manage their operation with the goal of minimizing the amount of weight and BCS loss between the time of calving and breeding. Drastic changes in BCS during late pregnancy and early lactation can make meeting management goals difficult and costly.
“Oklahoma State University, as an equal opportunity employer, complies with all applicable federal and state laws regarding non-discrimination and affirmative action. Oklahoma State University is committed to a policy of equal opportunity for all individuals and does not discriminate based on race, religion, age, sex, color, national origin, marital status, sexual orientation, gender identity/expression, disability, or veteran status with regard to employment, educational programs and activities, and/or admissions. For more information, visit https://eeo.okstate.edu.”