Get cows back in shape while it is cost effective
Producers in the north have a narrow window to easily put condition on a cow before the harsh winters set in. This is following weaning and before the negative temperatures and 40-mile-an-hour winds set in.
Cows should be sorted into different groups in the fall to maximize forage qualities and reduce costs. Sorting by each body condition score (BCS) category is usually not possible, so sorting BCS of 3s and 4s together, 5s and 6s together, and anything above a 7 together would be a good system. Most concentration should be on the 3 and 4 group as they need to move up most. The 5 and 6 group just needs to meet their requirements plus those of the fetus and they will be fine. The 7 and above group are the ones to utilize that lower quality roughage or just keep out on grass.
The following chart shows how much energy is needed to move to the next body condition score depending on the size of the cow.
Let’s run through a quick scenario for the BCS 3 and 4 cows. For a 1,200-pound cow moving from a 4 to a 5 BCS, the cow would need a total of 226 Mcal of energy beyond her daily maintenance needs. This 226 Mcal of additional energy could be supplied by dried distillers grains which has 1.22 Mcal of NEm per pound. If 4 pounds of distillers grains were fed, it would take about 46 days to elevate the cow’s body condition from a BCS 4 to a BCS 5. To determine approximate numbers using different feedstuffs, this equation can be used:
(Mcal Needed to Move to the Next Higher Body Condition Score (226)) / Lbs. of feed (4) *Mcal NEm of feed (1.22) = number of days needed to be fed (46 days on feed)
Other feeds may be used but keep in mind a cow can only consume so much. As the NEm goes down, the more the cow has to consume to reach the desired target within a given time span. A cow must meet its “normal” daily nutrient requirements before they are able to gain weight.
By sorting cows according to body condition, a producer can feed accordingly to the amount of weight needed and quality of feed stuff, thus cutting costs and saving much-needed higher quality forages for calving and breeding. One final thought to keep in mind for the cows that are in good condition is that as the range goes dormant and forage protein drops, it is a good idea to supplement a small amount of protein for utilization of that low quality forage. — Heather Larson, South Dakota State Universit