Little response has been reported when animals are only fed enough to support growth of less than 0.5 kg per day. Increasing the number of implants does not improve the response and repeating the dose has not shown any consistent additional benefit. The few comparative trials done in Australia have not shown any consistent difference in performance between the different growth promotants. For most producers, the choice of HGP will depend on the likely response rate, cost and ease of application using their cattle handling facilities. These questions can be answered by the stockists of hormonal growth promotants When treating cattle, ensure the timing of the implantation takes into account the annual cycle of pasture growth, feed availability and the intended date of slaughter.
Timing is critical when treating suckling calves with growth promotants.
They should be growing at least 0.6 kg per day before worthwhile responses can be anticipated. Growth rates to weaning may be improved by implanting calves at four to five months rather than at one to two months. Yearling steers Yearling steers are the most responsive type of cattle if they are grazing on good quality pasture or are fed in a feedlot. Weight gains are usually increased by 10 per cent to 15 per cent from one implant. Heifers Growth promotants cannot be recommended for breeding heifers without qualification.