Weaning is a good time to evaluate your cows to determine average body condition score of your herd.
What does a body condition score (BCS) tell you?
It is a visual estimate of the energy balance of the cow herd. It is based on a 9 point scale with 1 being emaciated and 9 being obese.
What is the optimal BCS at calving?
The goal is to have cows at a BCS 5 at calving. A BCS 5 refers to a cow with a generally good overall appearance, the fat cover over the ribs feels spongy and palatable fat cover on either side of the tail head. Since heifers are still growing, a BCS 6 is recommended at calving. BCS 6 animals will have a high degree of palpable fat over the ribs and around the tail head and firm pressure is needed to feel the spinous processes. View Basics of Body Condition Scoring (BCS) to learn more on how to body condition score.
If I calve in the spring, why am I concerned about BCS this fall at weaning?
To move a cow 1 full body condition score, requires a cow to gain 75 to 100 pounds of body weight. While she is lactating or during rapid fetal growth in late gestation the more challenging and expensive it is to change a BCS. During late gestation, a fetus will grow by 70%, taking up more room in the body cavity and displacing the rumen. As a result a higher quality feed needs to be fed, to offset the inability of the rumen to hold more feed. At the same time the rumen is being displaced, the cow’s requirements are increasing making it more challenging. While at weaning, the cow’s nutrient requirements are at her lowest. Perfect opportunity to put additional condition on a cow.
Why is it important to determine BCS?
A cow’s body condition score prior to calving has the largest impact on re-breeding success. Important research by Selk et al. in 1986 reported 88-98% of the cows in a BCS 5 or greater at calving were cycling at 80 days postpartum, compared to 62% of the cows in BCS 4 or less. Also pregnancy rate was lower amongst BCS 4 or less cows compared to the cows 5 or greater (61% vs. 90%). Based on this research, 38% of the cows that were not cycling by day 80 post calving will not maintain a 365 day calving interval and should be culled from the herd.
What factors influence BCS?
Age, lactation, feed quality and availability, and parasite load are all factors that influences BCS. Young, old and heavy milking cows are typically the thinner cows in the herd. Lack of quality or quantity of feed (i.e. grass) during drought or poorly managed grazing will draw cows down. Regardless if cows are thin due to drought, age, or lactation, early weaning may be the best option to increase BCS prior to late gestation. A 3 year research study conducted at the NDSU Dickinson Research Station, noticed cows that had their calves early weaned gained body condition from August to November. While cows that were in the November weaned group lost BCS during the same time period. During the same research, an average herbage savings of 18.9 lb/cow/day or 36%, resulted when early weaning was used as a management.
Source: Robin Salverson, iGrow