Are there ever reasons not to implant stocker and feeder calves?
The majority of stocker and feeder calves are implanted at the beginning of the grazing or feeding period. To optimize growth and feed efficiency, they are commonly re-implanted with the same or another product after the proper time interval for the particular implant used. There are reasons for not implanting such calves. One is having a niche marketing strategy such as “natural” unimplanted beef. Another reason is concern that some implants may reduce quality grade (see Table 1) when calves are sold based on carcass quality grade. Also, implanting will not be economical if stocker calf gains are low (<1.3 pounds per day) in programs where calves are being grazed for long periods with little supplement. Are there ever problems with implanting and re-implanting feeder heifers? If heifers are implanted with a product containing an estrogenic hormone shortly before weaning, and are then re-implanted with an estrogenic implant shortly after weaning, "estrogen stacking" may occur. Such hei
