by Warren Rusche, SDSU Extension Cow/Calf Field Specialist, SDSU Animal Science Department
Successfully managing drought conditions requires balancing the amount of forage demanded by grazing livestock with the amount produced. Early weaning can be a very effective tool for accomplishing that objective in the right circumstances.
Management Strategy: Early Weaning
There is an excellent reason why ranchers use early weaning as a drought management tool; weaning calves early reduces the amount of feed required to maintain the cow. Ending lactation reduces the cow’s nutrient requirements and dry matter intake compared to when she is nursing a calf, even during late lactation. Calves consume approximately 2.0 to 2.5{75e25ebeb47fb4337942be2c10689dca1c292c2a66240b62c5ca4214f5b25ecc} of bodyweight of dry forage; weaning early eliminates that forage demand as well. The combination of these two factors results in 30 to 40{75e25ebeb47fb4337942be2c10689dca1c292c2a66240b62c5ca4214f5b25ecc} less daily forage consumption.
Research conducted by SDSU demonstrated that weaning calves 90 days earlier cut forage disappearance by 36{75e25ebeb47fb4337942be2c10689dca1c292c2a66240b62c5ca4214f5b25ecc}, or 18.9 pounds per head per day. That equates to an additional 1.1 AUM in additional grazing available which should help ranchers reduce the number of cows that need to be moved off grass and reduce the risk of over-grazing.
Reproductive Benefits
Early weaning can also support greater reproductive success in some circumstances. Research results from the SDSU Cottonwood Research Station showed that early weaning improved AI conception in mature cows fed an energy-restricted diet after calving the next year, but had no effect if the cows’ diet was adequate (Table 1). These results suggest that weaning calves from mature cows early may improve reproduction if drought-stress causes cows to lose weight and body condition after calving.
Table 1. Effect of Weaning Date and Postcalving Nutrition on Cow Performance
Early weaned calves generally are more efficient compared to calves weaned at older ages, as long as they have high quality diets to eat. Feed conversions around 5:1 (feed:gain) are certainly possible. Calves of this age (100 to 150 d of age) require a diet that contains about 16{75e25ebeb47fb4337942be2c10689dca1c292c2a66240b62c5ca4214f5b25ecc} crude protein and 70{75e25ebeb47fb4337942be2c10689dca1c292c2a66240b62c5ca4214f5b25ecc} TDN. Typical diets are about 60{75e25ebeb47fb4337942be2c10689dca1c292c2a66240b62c5ca4214f5b25ecc} grain, 10-20{75e25ebeb47fb4337942be2c10689dca1c292c2a66240b62c5ca4214f5b25ecc} higher protein ingredients, with the balance of the ration comprised of higher fiber/roughage feedstuffs, as well as vitamins and minerals.
Challenges
Marketing early-weaned calves at weaning can be a major drawback to this system. Younger calves will obviously weigh less, and might bring fewer dollars to the ranch, depending on the price slide in place at sale time. Another obstacle is finding buyers that want to feed and buy lightweight calves. Not every feeder is set-up to handle and manage very young cattle, which can affect the number of potential buyers and how aggressively they bid on lightweight calves.
Some producers have successfully weaned calves on pasture with a creep feeder. Once calves were consuming sufficient amounts of creep feed, the cows are sorted off leaving the calves behind. Using feedstuffs such as small grain regrowth, cover crops, or crop residue is another strategy to cut costs.
Calf health can be another concern. Because these calves do not have to deal with colder, wetter weather, they can transition through the weaning process relatively well provided they consume enough feed during the receiving phase. Producers should consult with their veterinarian for a vaccination and health plan specifically designed for their operation.
Source: iGrow, SDSU Extension
