Implanting Nursing Calves

By : Grady Ruble, SDSU Extension Cow/Calf Field Specialist, Courtesy of


Implanting nursing calves has consistently shown to be an effective way to post greater calf weights at weaning time. In fact, implanting has the greatest return on investment of any other technology, which ultimately makes the decision of which implant to use of lesser importance than the decision to implant.

However, an implant must be chosen, keep in mind proper placement is vital to the success of the implant. But in general, any of the implants approved for suckling calves will provide positive results. Here are a few things to consider when attempting to decide which implant is right for your operation.

Implant Considerations

In general branding makes for a convenient time to administer suckling implants. A review conducted by Selk (1997), demonstrated that the use of a conventional implant increased average daily gain prior to weaning approximately 5% over non-implanted controls. However, the amount of time between spring branding and weaning is often longer than the payout of conventional implants. Re-implanting is a viable option that has been shown to provide benefit beyond that of a single implant prior to weaning (Selk, 1997). Extended-release implants are a useful option since they would provide coverage for the additional time.

There are a couple different types of extended-release implants, one of which is Compudose. Increases in pre-weaning average daily gain associated with Compudose have been demonstrated to be about 4% greater than non-implanted calves (Selk, 1997). Another extended-release implant available is Synovex One Grass. A recent study by Gentry et al. (2019), found that steer calves implanted with Synovex One Grass were approximately 26 pounds heavier at weaning time than non-implanted steer calves.

Another implant strategy illustrated by Pritchard et al. (2015), which examined the impact of cow age on calf response to an implant administered in May or August. The trial consisted of 3 treatments; 1) non-implanted controls; 2) Synovex C implant administered in May; or 3) Synovex C implant administered in August. Cows 4 years of age and greater were considered mature and those less than 4 years of age immature. Steers suckling mature cows achieved greater weaning weights when the implant was administered in May. Conversely, when cows were immature, weaning weights were greater when calves were implanted in August. These data lead to an idealized implant strategy where steer calves would be implanted either in May or August based exclusively on age of dam. This approach would ultimately yield the largest amount of total pounds of calf weaned, as opposed to all steer calves receiving a Synovex C implant in either May or August.

A common concern is that a calf hood implant can negatively impact future post weaning performance. However, multiple studies have provided evidence that a suckling implant was of no detriment to subsequent feed lot performance and the weaning weight advantage was actually maintained at slaughter (Mader, 1997; Pritchard et al., 2003; Pritchard et al., 2015). This is especially impactful because at the end of the day the whole industry benefits from additional weight.

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