Advances in Reproductive Technologies in Beef Cattle.

 By Heather Smith Thomas.

 Dr. Carla D. Sanford with Dean Farms of Georgia gave a presentation on beef cattle reproductive technology advances at the first RancHER program hosted by Oregon State University in December, discussing recent trends in reproductive technologies for beef cattle.

Carla earned her Ph.D. at the University of Florida; her graduate work focused on fetal developmental programming. She continued research at Montana State University, where she was an assistant professor and beef cattle specialist. She is now back on her family’s cow-calf operation and says reproductive performance is critical for success.

A reproductive herd plan may consist of several assisted reproductive technologies, including estrus synchronization, artificial insemination (AI), embryo transfer (ET), in vitro fertilization (IVF) or ovum pickup. In her presentation for the RancHER program, she discussed the foundation of a sound reproductive herd plan, where to start and how to get the most from a breeding program.

She talked about the impact of reproductive efficiency and how important it is to the beef industry and some of the things a producer can do to optimize reproductive efficiency. “Data from the Beef Cattle Research Council in 1977 showed reproduction is five times more important than growth rate and 10 times more important than carcass quality,” she said. A cow must first become pregnant and have a calf before you can think about the growth and quality of that calf.

“Reproduction is still the number one thing to be concerned with. We need to keep pushing the envelope to get more females to conceive in the first 21 days of breeding season and get the highest number of calves from genetically superior bulls,” she said. There are several strategies to improve reproductive efficiency in terms of selection pressure, management of the operation, using a controlled breeding season and, sometimes, using two breeding seasons.

“Twenty years ago, embryo transfer was the cutting edge of bovine reproduction, but now we talk about ovum pickup and IVF as the next step in these technologies, and people are also using sexed semen in beef cattle,” Sanford said.

The typical beef producer may not be currently using some of these technologies, but there is a place for this, especially for seedstock operations. A purebred breeder might want to produce more bulls. A commercial cattleman might want to produce nothing but replacement heifers from their best cows.

Many producers use AI, and it’s easier when all the cows or heifers can be bred in a short time instead of having to spend time heat detecting. “New estrus synchronization protocols are constantly being developed. Some people wonder why we need researchers working on these because we already have protocols that work, but it’s because we can do a lot more with it now. Use of sex-sorted semen or sex-selected embryos wasn’t common 10 years ago, but is becoming more common. Research is answering questions about what can be done and the time frame,” she said.

“For example, we now know we can eliminate the need for injecting all females with gonadotropin-releasing hormone (GnRH) at timed AI and only give it to those that did not show standing head. We can have more precision in breeding management and eliminate extra injections when possible.

“If there’s an issue with weather or labor, we may need options on what we can do. Some people think estrus synchronization is only used with AI or embryo transfer, but you can also take advantage of estrus synchronization with natural service. And, there are times when your labor doesn’t show up, or semen doesn’t come on time, yet the females are synchronized. You can change plans. If the bulls are tested and ready, you could simply turn them out and still be successful.” It pays to have a backup plan.

Producers should be realistic about their goals and expectations when adopting a new technique like AI, ET or IVF, knowing you’ll get better at setting up females over time and working with a breeding technician. “When there’s a low conception rate or some other problem, it’s also easier to trace back and determine what the issue might be if you keep good records and make sure the animals have good nutrition and have a good veterinary-client relationship in place. It helps to check all the boxes,” she said.

In her presentation, she discussed synchronization tools—progestin, prostaglandin and GnRH. It is important to know the pregnancy status of females before starting a protocol. “When using a prostaglandin, be sure those females are not already pregnant because it can cause abortion in cattle up to five months gestation.”

The estrus synchronization planner is a free tool producers can use for selecting a synchronization protocol, and it is managed by the Beef Reproduction Task Force (BRTF)—a team of researchers, Extension faculty members and industry individuals.

“I started using this in graduate school and have used it ever since. This tool is a free Excel spreadsheet you can utilize for one herd or multiple herds. You select the type of cattle (Bos taurus or Bos indicus, heifers or cows), what time you want to breed them and when to start breeding. It gives the recommended protocol for what you’ve chosen and a cost analysis to help you decide what protocol would be best costwise and for number of trips through the chute,” Sanford said.

The BRTF keeps producers updated on all protocols. Every year, the team goes through all the research from the preceding year and all the data. “If any substantial new contributions have been made, they update their recommendations,” she said.

There might be new research on timing of insemination, for instance. The BRTF does the footwork to improve the recommendations. “This is why the protocols for heifers and cows in the AI companies’ brochures have a year date on them, because each year there could be a potential improvement or update,” Sanford said.

The estrus synchronization planner has a tab that includes the newest protocols. “I’ve synchronized females for other people and can print this out or email it to them, showing that on such and such day they will be giving this injection and dosage. The planner creates two different calendar-type spreadsheets you can print out and use or send to someone or put on a bulletin board in the ranch shop—so everyone knows what’s going on when you are working cattle and what you will be doing with them.”

She explained the recommended protocols for heifers versus cows, and the seven-day CO-Synch + CIDR protocol. “You can use that for heifers and cows, but the timing from when you remove the CIDR until you inseminate is shorter in heifers,” she said.

“I also talked about bulls, serving capacity, bull to heifer ratio, etc. We’ve looked at research comparing groups of heifers that were synchronized versus groups that weren’t, and the bull-to-heifer ratio in those groups,” she said.

She also mentioned recommendations regarding hauling cows/heifers after conception. It is relatively safe to haul within the first four days, which is prior to the embryo moving into the uterine horn—attachment of the embryo to the uterine wall has not occurred yet. After that, the stress of transport (before the embryo is safely attached to the uterine wall) may create risk for early embryo loss.

“We also want to make sure we’re using low-stress handling practices and have adequate facilities. Stress can increase cortisol production, which can block luteinizing hormone release. This can prevent ovulation. We don’t want to put those animals through unnecessary stress, and certainly not to the level of compromising ovulation and conception.” — Heather Smith Thomas.