Estrous Synchronization: Taking the Guesswork Out of Breeding

Less then half of all dairy producers are estimated to use estrous synchronization protocols in the reproductive program of their cows. Nevertheless, this innovative technique is becoming more and more popular as a means to increase efficiency and profits.

It’s a technology that is coming of age in the dairy industry: synchronizing the sexual receptivity and ovulation of a group of cows.

Clearly, this approach, which employs naturally occurring hormones to “time” cows’ reproductive cycles, is becoming accepted as a sound way to increase the chances of conception and pregnancy, reduce labor costs and ultimately enhance profits.

Alvaro Magalhaes, DVM, knows all about estrous synchronization (ES). In fact, he is responsible for orchestrating the conception of thousands of dairy calves each year.

He works with large dairies—between 900 and 6000 cows—in California’s Central Valley. Most of these operations employ synchronization protocols at one level or another. At one dairy he is responsible for the embryo transfer program and implants 3,500 to 4,000 embryos annually.

There are a number of reasons why such dairies invest in estrous synchronization programs. The first is related to farm operations. Even at the best facilities, cows are becoming more and more confined, Magalhaes contended. So, it is more difficult to observe their estrous behaviors. That means that many opportunities are missed for breeding or artificial insemination (AI).

In addition, high producers, generating 100-130 lbs of milk a day, also have high rates of metabolism. They don’t show the signs of heat as readily, which can make observational breeding more challenging, and again opportunities are lost. With ES, ovulation can occur in a more precise window of time, so heat detection can be minimized or eliminated.

And, that’s important when you consider what a challenging and pricey proposition heat detection is, in terms of the labor required.

“We don’t have enough qualified breeders available to be around the cows 24/7 just for heat detection,” said Magalhaes who has been practicing veterinary medicine for 34 years.

Put all these things together, he says, and “it’s a lot easier and way more efficient—and a lot safer for the cow—when you do synchronization protocols.” The safety, Magalhaes added, is derived from giving cows the proper care at the right moment and avoiding breeding accidents.

The economic benefits are beginning to emerge, too. Magalhaes said that ES programs can double the pregnancy rate of a given group of cows. And, with the high cost of extra open days, the savings can add up pretty quickly.

Of course, ES is not cheap. But, experts say the savings far outweigh the cost of such programs. There are about 20 different routines or protocols that dairy producers can select, depending on their specific situations, he said. The mainstays of the program are hormones that are injected at carefully timed intervals to make cows ovulate at a specific time.

“We synchronize cows to have a specific time to breed them, so instead of chasing cows throughout their 21-day cycle, we chase them for 1-2 days,” Magalhaes explained. “We don’t synchronize the whole herd to breed at the same time; we work groups of pens. So, every week or every other week, you are going to breed a specific group.”

The primary hormone used for ES is prostaglandin (PGF). Simply stated, PGF is a naturally occurring hormone the uterus releases to tell the ovary to start another estrous cycle. The most basic ES protocol is to inject PGF in a group of cows that are between day 6 and 16 of their cycles. The breeder will know the cows should come into heat in three to five days, so he can breed that group of cows.

Other more elaborate and efficient protocols call for two shots of PGF, at alternating times, or the use of gonadotropin-releasing hormone (GnRH), which stimulates the formation of a new follicle. Such protocols can incorporate natural breeding or artificial insemination. Many experts recommend artificial insemination with ES to eliminate the risk of managing the large number of bulls required for breeding groups of cows. Also, in most cases AI is more efficient and cheaper than natural breeding.

When considering implementing an ES program, there are several important things to assure your success, Magalhaes advises. The first is to identify a good veterinarian who is familiar with ES protocols to set up the program. The second is to assemble a well-trained team to implement the program.

“All people involved must really understand what they are doing, why they are doing it and when they have to do every single step,” he emphasized. “Educating and training the staff is very important.”

Magalhaes offers that one of the biggest mistakes dairy producers make is selecting cows that are not ready for the program. Cows must be healthy and at least 45 days from their last calving to be included in an ES program.

The other common mistakes result from lack of training, poor record keeping or lax compliance.

“The big, big secret—once your protocols are established—is compliance,” he stated. “Every injection must be done at a specific time. You have to have the right people to do the right shots at the right time. If you don’t, you can hire others to do this for you.”