Reproduction is the single-most important factor in profitability in cow-calf herds, says University of Nebraska animal scientist and beef reproduction specialist Rick Funston, PhD. And in today’s market, a high calving percentage, and a high percentage of calves born early in the calving season, add more than ever to a rancher’s bottom line.

Speaking to veterinarians during the recent American Association of Bovine Practitioners (AABP), Funston outlined research into heifer development, nutrition as it relates to reproductive efficiency and reproduction technologies including estrus synchronization and artificial insemination (AI).

A relatively small percentage of cow-calf producers use synchronization and AI, and the majority of the ones who do limit their use to replacement heifers and use natural service with older cows.

Funston believes many ranchers could benefit by shifting toward AI, with, in many cases, the assistance of their veterinarian. Those benefits include genetic progress toward herd goals using high-merit AI sires, and also the opportunity to tighten the breeding season and shift more calves into the early part of the calving season. That results in more uniform, heavier calves at weaning and sale time, and helps assure their dams rebreed in a timely manner. Heifers conceived during the first breeding cycle have heavier weaning weights, conceive earlier as yearlings, rebreed quicker, wean heavier calves and stay in the breeding herd longer than those conceived later in the breeding season.

Funston acknowledges that synchronization and AI entail extra labor costs, facilities and skills that discourage some producers, but also notes those costs tend to balance with the cost of natural service, since producers do not need as many bulls. He also notes that producers do not necessarily need to use AI to gain the benefits of estrus synchronization. In the University of Nebraska herds, he says, managers use a relatively simple synchronization with natural service, administering prostaglandin to females five days after turning out the bulls for breeding. They achieve an 85 percent pregnancy rate with a 45-day breeding season.

Funston outlined the variety of synchronization protocols currently recommended for cows and heifers. Each has its benefits and weaknesses depending on an operation’s breeding schedule, facilities, labor and other variables. The options can seem complicated, but the Beef Reproduction Task Force, a coalition of researchers and reproduction experts have compiled a wealth of practical information on the Applied Reproductive Strategies in Beef Cattle (ARSBC) website at The resources section of the site includes:

  • A free Estrus Synchronization Planner
  • AI Cowculator
  • 2014 Estrus Synchronization Protocols for heifers and cows
  • 2014 Protocols for Synchronization of Estrus and Ovulation
  • A guide to the bovine estrous cycle
  • Detection of Standing Estrus in Cattle
  • Estrus Synchronization--Planning for Success
  • Tips for a Successful Synchronization Program
  • Use of Natural Service Sires with Synchronized Estrus

Funston also notes the 2014 ARSBC Conference will take place October 8 and 9 in Stillwater, Oklahoma, providing interested producers, veterinarians and others with the latest information on reproductive strategies. Details and registration information are available on the site.