The World's source for Bovine Genetics
SELECTIONS - Winter 2005
Ovsynch: Another Reproductive
Solution From Select Sires


by Jenny Byl, contributing writer

One challenge that may be keeping you from getting the pregnancy rate you want is heat detection.

Detecting cows in heat may be one of the most time consuming tasks on dairy farms today. As a result, more and more dairy producers are adopting breeding programs such as Ovsynch into their reproductive routines.

Just one of many options in the Select Sires Portfolio of Reproductive Solutions™, Ovsynch was developed in 1995 to synchronize ovulation for timed breeding. It is appealing to many producers because the program doesn’t rely on heat detection for breeding cows.

One of the biggest attractions to the Ovsynch program is the success with pregnancy rates. While the pregnancy rate for an exceptional traditional program will seldom exceed 20 to 25 percent (most herds have an overall average of 16 percent), Ovsynch pregnancy rates are typically around 30 to 35 percent, says Mel DeJarnette, Select Sires reproduction specialist.

How It Works

Ovsynch begins with an injection of GnRH that can be given to lactating dairy cows at any stage of the estrous cycle. It affects follicular growth by causing either luteinization or ovulation of the dominant follicle and prevents estrus until after the prostaglandin F2α (PGF2α) injection is given seven days later. PGF2α causes the corpus luteum or luteinized follicle to regress and a new dominant follicle then forms. It is available to be ovulated by the second GnRH injection, which is given two days after the PGF2α injection. Cows then receive a timed A.I. between eight and 18 hours after the second GnRH injection without regard to estrus behavior.

Timing Is Everything

Optimum conception rates for Ovsynch appear to occur when cows are 65-75 days post-partum at the time of insemination. Thus, dairy producers should begin the Ovsynch protocol at 55 to 65 days after parturition. If a cow does not become pregnant, producers should start her back on the protocol as soon as possible to ensure timely re-insemination, says DeJarnette.

Ovsynch Protocol


The Challenge

The most difficult part to implementing the Ovsynch protocol is maintaining the appropriate interval from the second GnRH to A.I. In most herds, there is a single time during each day that is most convenient to handle or “lock-up” cows for injections and A.I. The eight-to-18 hour interval from the second GnRH to A.I. often means cows must be handled when it is very inconvenient to do so, says DeJarnette.

The impact of Ovsynch in a breeding program depends on each herd’s management and facilities. Cows must be accessible for three different injections, and the record keeping and/or scheduling system must be able to ensure the right cow gets the right injection at the right time on the right day.

"Injection scheduling is sometimes the most difficult part of Ovsynch," comments DeJarnette, emphasizing, "Lack of compliance becomes the primary factor limiting the success of Ovsynch and any other breeding program.

"Work with your Select Sires representative and veterinarian to develop a reasonable goal and plan, then stick to it," he advises.

Questions?

Think Ovsynch may be right for your herd? Have questions about other reproductive programs? Select Sires Reproductive Solutions Specialists can design a customized reproductive program tailored to your needs. Contact your representative today to discuss options for your herd.



™Reproductive Solutions is a trademark of Select Sires Inc.

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