BLUE SPRINGS, Mo. -With water and feed resources for cattle limited by hot, dry weather, management and selective culling is important to maintain a viable herd and maximize performance of the limited resources, says a University of Missouri Extension specialist.
Weaning spring calves early is one way to reduce nutritional requirements for cows, says Patrick Davis, livestock specialist in Johnson County.
"Early-weaning calves can take place as early as 45 days of age," he said. "Early weaning will reduce cow forage intake by 0.4 to 0.7 pounds per 100 pounds of cow body weight, which is an average savings of 7 pounds of dry matter per day."
It is important that the early-weaned calves go through a full vaccination schedule and precondition period for 45 days prior to sale, he added. "This allows the calves to get over the rigors of weaning and be healthy at sale time."
Important things to assess at weaning time that can be used as culling factors on these spring-calving cows are age, body condition and pregnancy status.
Pregnant cows should be retained. Place the others in a group considered for culling. Next, consider the cow's body condition and age.
"Younger cows that are in condition score 5 or 6 should be retained," Davis said. Older cows in condition score 3 or 4 (which show visible signs of ribs and backbone) should be placed in a group considered for culling.
"If thinner pregnant cows are maintained in the herd, separate those from body condition score 5 and 6 cows," he said. Thinner cows will need supplement and free-choice pasture or hay to return to condition score 6 by the next calving season.
"When determining pregnancy status of the cows, you may notice that your first-calf cows are coming up not pregnant," he said. That's not surprising given the heat, decreased pasture resources and the continued growth of these cows.
Should you cull these cows because they are not pregnant or do you roll them over into the fall calving herd?
"To make this decision you have to take into account the present resources and the cost of purchasing or developing a replacement heifer," Davis said.
If resources are available to carry this cow over to the fall-calving herd and it is cheaper than developing or purchasing a heifer to replace her, then retain her in the herd, he said. But if resources are limited or she is bred to fit into the fall calving herd and comes up open, then cull the cow.
Another culling criterion is calf performance. "The main objective of a cow-calf operation is weaning as many pounds of calf as possible. Look at pounds of calf weaned by the cow for this year and previous years." Consider culling cows that wean fewer pounds of calf.
These tips for identifying animals for culling will leave the cattle producer with cows that require minimal feed resources to maintain condition, have adequate condition to become pregnant during the subsequent breeding season and produce a high-performing calf during the next production cycle," Davis said.