Implanting nursing calves is one of the most cost-effective practices available to cow-calf producers. Preweaning implants are typically given when calves are 2 to 4 months of age, often when cows are being prepared for breeding and moved to summer grazing. Research shows that implants given during the suckling phase increase average daily gain by 0.15 pounds per day and weaning weights by 25 pounds.
Implanting heifers at birth can reduce future pregnancy rates by 30 to 50%, so that practice should be avoided in potential replacement females. However, research indicates that implanting heifers between 1 and 3 months of age does not negatively affect pregnancy rates later in life when approved products are used correctly.
Despite the economic benefit, adoption remains low. The Oklahoma cow-calf survey indicated that only about 20% of producers implant calves before weaning. Research from Kansas State University and Merck Animal Health evaluated more than 15,000 lots of calves sold through Superior Livestock Auction, representing over 2.5 million head. In that analysis, implanted calves were not discounted. With today’s calf prices, a 25-pound increase in weaning weight is worth $125 to $150 per head. Not implanting is the equivalent of taking a $25 per hundredweight discount on your calves.
Another common practice is leaving bull calves intact until weaning in hopes that natural hormones will increase gain. However, bull calves produce very little testosterone prior to puberty, which occurs much later than normal weaning age. Numerous research trials have shown that implanted steer calves gain faster and wean heavier than intact bull calves.
Delaying castration until weaning also adds stress at the same time calves are adapting to separation, marketing, transport, and new diets. This stress can reduce post-weaning performance and increase health risk. Buyers recognize these risks, which is why steer calves often sell for $12 to $15 per hundredweight more than intact bull calves.
Producers wanting to maximize calf value should consider early castration along with an implant approved for nursing calves. Used at the right time, implants can return $100 to $150 for every dollar invested and help offset today’s higher production costs.
