Using Body Condition Score to Determine Feed Requirements
By David E. Panksakie, M.S., Nutritionist
A beef cow’s nutrient requirements are determined by her age, body condition, reproductive status, and other factors such as the environment, disease, parasite load, etc. Hay or pasture is the primary feed resource for most beef cow feeding programs. The pasture and hay commonly fed to beef cows do not provide all the nutrients needed during the most nutritionally important period in a cow’s year, the last trimester of pregnancy, through breeding. Supplemental protein, energy, minerals, and vitamins are often needed during this time for optimum reproductive performance. The amount of supplemental feed required is greatly influenced by the quantity and quality of forage available. This is even more critical during periods of drought when forage supply is limited and lower quality forages such as straw and stalks along with purchased hay are used as part of the cow’s forage feeding program. Incorporating lower-quality forages into the feeding program often requires additional supplementation, especially protein and energy, minerals & vitamins.
The Importance of Body Condition
The amount and type of supplemental feed required for optimum reproductive performance is also influenced by the cow’s body condition or the amount of fat a cow has in reserve. Body condition scoring is a management tool that assigns each cow a numerical score of 1 to 9 based on her degree of fatness. A body condition score of 1 represents a very thin cow and a score of 9 represents an extremely fat cow. In order to optimize reproductive performance, body condition scores should fall within a range of 5 to 7 at the beginning of the calving season and remain there until the end of the breeding season. Maintaining proper body condition is important in a normal year, but it is especially important under drought conditions when beef cows often become thinner than normal due to the lack of good quality forage.
The body condition of beef cows at calving can have a significant impact on post-partum interval, calving interval, lactation performance, and the health and vigor of newborn calves. Post-partum interval is the number of days between calving and breeding, while calving interval is the amount of time between the births of one calf to the birth of the next calf. In order for a cow to have a 12-month calving interval, she must rebreed within 80-85 days after calving. Research has shown that the percentage of cows cycling 60 or 90 days after calving is significantly lower for cows with a body condition score of 4 or less compared to cows with a body condition score of 5 or higher. Thin cows that take up to 200 days to rebreed will not have a 12-month calving interval, which reduces herd productivity and profitability. Contrary to popular opinion, cows with body condition scores of 5 or higher at calving do not have more calving difficulty.
Supplemental Feeding Based on Body Condition
Ideally, cows should be separated into 2-3 groups based on age and body condition and fed according to their needs. The most practical times to body condition score cows are at weaning, 60-90 days prior to calving, at calving, and just prior to breeding. Determining body condition at weaning gives the producer adequate time to adjust the feeding program in order to achieve the proper body condition at calving. This is also the time in the cow’s reproductive year when her nutrient requirements are the lowest and therefore the time when the least amount of supplemental feed is required in order to improve body condition.
Under drought conditions, cows often lose body condition during the grazing season and during the fall and winter due to the lack of available forage. Therefore in order to achieve proper body condition at calving, cows often need to be fed to gain weight and body condition during the 90-120 days prior to calving. The amount and type of supplemental feed required are determined by the cows body condition score prior to calving and the amount and type of forage available. It is estimated that it takes approximately 75 pounds of weight gain in order to increase a cow’s body condition by 1 score. For example, if a cow is a body condition score 3, 100 days prior to calving, then she will have to gain 150 pounds (2 body condition scores X 75 = 150 pounds) in 100 days or 1.5 pounds/day. The table below shows the pounds and type of supplemental feed needed daily during the 100 days before calving by a mature pregnant cow when fed forage of different quality in order to reach an optimum body condition score of 5-6 by the start of the calving season.
Body condition is a significant factor in determining the cow’s energy requirement. However, it has only a small effect on protein requirements and little or no effect on mineral or vitamin requirements. All cows require some protein supplementation, regardless of body condition and the quality of forage fed in order to efficiently utilize the energy found in the forage.
Drought conditions or feeding low-quality forages necessitates that more of the cow’s mineral and vitamin needs must come from a properly balanced mineral/vitamin supplement. It is recommended that minerals such as WFM Cow/Calf, Stress Aid or Range Breeder be provided at all times.
It can be seen from the table that thin cows, those with a body condition score of 4 or less, require a fairly large amount of supplemental energy along with supplemental protein. A product such as WFM 14% RANGE CAKE or 14% Hi ENERGY CAKE is recommended in that situation. For cows with a moderate body condition score of 4, a medium protein supplement such as WFM 20% RANGE CAKE or 20% DROVER’S CAKE can be fed to provide both supplemental energy and protein. When cows are at the desired body condition of 5-6, 1.0 to 2.0 pounds/day of WFM 38% RANGE CAKE will provide all the supplemental protein the cow needs. Keep in mind, however, that cows in good body condition fed a poor grass forage, winter range, or crop residue along with adequate protein supplementation, may not receive enough energy to maintain that body condition. This is especially true as cows approach calving seasons and breeding and nutrient requirements increase significantly.
Summary
In order for a beef cow herd to remain profitable, the cows should be kept in proper body condition at all times. This insures that the cows will breed on time and in a short amount of time in order to produce a marketable calf every 365 days. Producers need to recognize that the cow’s nutritional requirements change throughout the year depending on her reproductive status. Forage quality and availability also changes throughout the year and can be dramatically affected by drought and other adverse growing conditions. Producers should always allocate feed resources according to the cow’s changing nutritional needs. Body Condition scoring cows several times during the year gives producers adequate time to adjust the feeding program in order to maintain a relatively constant body condition. Remember it is usually easier and cheaper to add body condition to a cow when her nutrient requirements are the lowest rather than wait until just before calving when the cow’s nutrient requirements are the highest.
For more information on using Body Condition to determine a cow’s feed requirements, contact Western Feed Mills or your estern Feed Mills representative. For more information of how to body condition score cows, please refer to Oklahoma Cooperative Extension Fact Sheet ANSI-3283 BODY CONDITION SCORING OF COWS or Kansas State University publication GUIDE TO BODY CONDITION SCORING BEEF COWS AND BULLS MF3274.