Ranchers who check their cows' body condition at fall weaning time can get thin animals into better condition and improve theodds of early calving next spring, a beef cattle specialist with NewMexico State University said.
“A cow that's in good condition should have a fertile ovulation earlier in the breeding season,” said Clay Mathis with NMSU's Cooperative Extension Service. “Cows that conceive earlier in the breeding season typically wean larger calves that are worth more money.”
A short, defined calving season allows ranchers to manage their herds more easily and market a uniform group of calves at weaning, he said.
To rate body condition, ranchers can use a scale that ranks cows by fatness, an indication of body energy reserves. “Research shows that cows' reproductive performance is closely associated with body energy reserves,” Mathis said.
A common scoring system ranks animals from 1 to 9, with 1 for an emaciated cow and 9 for an extremely obese animal, Mathis said.
“A good conservative target is for cows to be in a body condition score of 5 at spring calving,” he said. “Cows generally lose 40 to 60 pounds during the winter when forage is dormant, so if we think back to fall weaning, we'd like to see cows with a body condition score of 5 to 5-1/2.”
A score of 5 indicates an animal that is neither lean nor fat. Only one to two ribs are visible, individual muscles in the hindquarters are not apparent and no fat can be seen in the brisket area, Mathis said.
At fall weaning, ranchers can separate cows that score below 5 and provide additional nutrition for them.
“If we sort off the thin cows that are a higher risk of not becoming pregnant early in the breeding season, those cows can be placed in fresh pasture that has not been grazed or put into a drylot and fed all the hay they can eat for 30 days,” he said. “That should generally put on one body condition score, which would be equivalent to about 80 pounds.”
For an illustrated guide to body condition scores, contact Mathis at 505-646-8022.