Suckling calves show significant increase from implants

Strategic approach, timed for animal’s development, can maximize pounds gained

Recent studies of implant use in suckling calves revealed promising results for weight gain through the feedlot phase compared with nonimplanted cattle. In these studies, the nonimplanted cattle control groups simply couldn’t catch up to the implanted animals.

In the Field Observations podcast, Dr. Gary Sides discussed research studies from South Dakota State University and North Mexico State University that resulted in the significant weight gain demonstrated by strategic implanting. Listen to the podcast for the New Mexico State University results when the study was conducted with heifers.

The South Dakota State study was repeated over two consecutive years in Angus and Angus/Limousin cross steer calves on a ranch in western South Dakota. The treatment groups included:

• Nonimplanted control group 

• Implanted with SYNOVEX® C at branding in May 

• Implanted with SYNOVEX C at preconditioning in late August 

The results, Sides revealed on the podcast, showed a significant increase in weaning weights of steer calves that could be maximized using an implant strategy based on the age of the dam.1

 “If a producer implants calves from mature cows at branding, but delays implanting until preconditioning calves from younger cows, the overall response was an additional 35 pounds in weaning weights versus nonimplanted calves,” Sides said. “If calves from all ages of cows were implanted at the same time during branding, the growth response averaged 24 pounds of gain. 

 “So, the thing to remember here is that our producers need to match the potency of the implant to the nutritional status of the animal at the time of administration, with the dam’s age in mind.”

 Sides discussed what a possible implant program based on these results would look like.

  • Implant all heifers and steer calves with SYNOVEX C at time of branding (those that are at least 45 days of age and that come from dams 4 years of age or older). 
  • Implant all heifers and steer calves from 2-3-year-old cows at a later date, such as at preconditioning in August or September.
  • For calves from mature cows that are too young to implant at branding or less than 45 days or older, brand those calves at a later date and also implant at a later date, at preconditioning along with the calves from the 2-3-year-old cows.

Implants demonstrate success elsewhere, too

The use of SYNOVEX® One Grass and SYNOVEX C in studies conducted in Oregon and Washington also demonstrated that performance in suckling calves produced lifetime total gain throughout their lifetime superior to nonimplanted calves.2 

 Three groups of suckling calves were studied during a 200-day grazing period in Oregon and a subsequent 193-day feedlot period in Washington. Here are the results from that study.

• Implanted with SYNOVEX One Grass: Total gain advantage 45 pounds

o ADG over 200-day suckling: 2.15 pounds 
o ADG over 193-day feedlot period: 3.79 pounds 
o Lifetime ADG of 2.75 pounds 

• Implanted with SYNOVEX C: Total gain advantage 37.3 pounds 

o ADG over 200-day suckling: 2.08 pounds 
o ADG over 193-day feedlot period: 3.84 pounds 
o Lifetime ADG of 2.73 pounds 

• Nonimplanted control group 

o ADG over 200-day suckling: 1.95 pounds 
o ADG over 193-day feedlot period: 3.8 pounds 
o Lifetime ADG of 2.66 pounds 

 Visit to find the implant to fit your needs or visit with your herd veterinarian.

 Do not use SYNOVEX products in veal calves. Refer to label for complete directions for use, precautions, and warnings.

 About Zoetis
Zoetis is the leading animal health company, dedicated to supporting its customers and their businesses. Building on more than 65 years of experience in animal health, Zoetis discovers, develops, manufactures and commercializes medicines, vaccines and diagnostic products, which are complemented by biodevices, genetic tests and precision livestock farming. Zoetis serves veterinarians, livestock producers and people who raise and care for farm and companion animals with sales of its products in more than 100 countries. In 2019, the company generated annual revenue of $6.3 billion with approximately 10,600 employees. For more information, visit

For more information, contact
Kathleen McGinty

Lori Maude
Bader Rutter

1 Pritchard, RH; Taylor, AR; Holt, SM; Bruns, KW; and Blalock, HM. Time of Suckling Implant Influences on Weaning Weight, Post-weaning Performance, and Carcass Traits in Steer Calves. South Dakota Beef Report; 2015: 40-45. 
2 Data on file, Study Report No. 18CRGIMP-01-01b, Zoetis Inc.



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