“A common mistake is changing products but not changing the dosage.”
We have come a long way from the synchronization programs that involved one shot of prostaglandins, observation and breeding according to heat.
Prostaglandins are still a useful tool in combination with other drugs and intravaginal devices containing progesterone.
Many producers will have seen the various protocols for synchronization. American Breeders Service had a nice summary in one of its catalogues.
The only problem with so many choices is that it might become confusing, and disastrous results can occur if protocols are changed or times are not strictly followed.
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In my experience, the best protocol is the CO-Synch plus progesterone releasing intravaginal device (PRIDs or CIDRs).
Producers who follow this program should laminate the flow sheets and put them where they can easily be followed.
This program has a slight difference in the time period after the prostaglandin shot – six hours shorter for heifers.
It is good for allowing full synchronization so all cattle are bred at the same time. There is no need for heat detection.
Cattle are run through the chute three times over a 10 day period, including when they are artificially inseminated, so producers must have a good handling set up. Good facilities reduce labour and decrease stress on the cattle, which helps obtain higher conception rates.
As with all medicines, they should be kept from freezing or getting too hot. Shots are intramuscular so make sure to use at least a 1.5 inch needle and give the injections in the neck.
Because the dosages of GnRH (gonadatropin releasing hormone) and prostaglandin are smaller, it is critical to get them all into a site where they will be absorbed quickly. Products are available for both GnRH and prostaglandins, so cost has been reduced and most are marketed in larger bottles, making mass synchronization easier.
Fertiline, Cystorelin and Factrel are the three most common GnRH products and all have good efficacy.
As for prostaglandins, the two oldest ones are lutalyse and estrumate, but a new one, estroplan, has just been introduced. It is essentially a generic estrumate.
Don’t interchange these products because estrumate and estroplan have a two cc I.M. dosage while lutalyse is five cc I.M.
A common mistake is changing products but not changing the dosage, which results in underdosing or overdosing. That usually upsets any synchronization program.
For the dairy industry, PRIDs, Fertiline and all the prostaglandins have a zero milk withdrawal.
From what I have observed, PRIDs cause much less irritation in the vagina than CIDRs. In larger cows, they must be unrolled and kinked in the middle, which helps them stay in the vagina. This is a necessary procedure to minimize losses. As with CIDRs, tuck the string inside the vaginal lips.
This kinking procedure is unnecessary with heifers because the vagina is smaller and tighter so losses are negligible.
Keep a cow in the program even if the PRID goes missing. You don’t know when it was lost and synchronization may still work.
PRIDs have enough progesterone to be used twice, but the jury is still out on this practice. I believe there are disadvantages.
The progesterone in CIDRs has recently been cut back so they can be used only once, which is an economic consideration if wishing to reuse the device.
Producers who do multiple synchronizations must keep track of which PRIDs are being used a second time. There is always the issue of transmission of reproductive diseases, although the use of artificial insemination minimizes this possibility. All the intravaginal devices become grungy and are a pain to clean and store till the next use. As well, the strings generally need to be replaced.
PRIDs have recently come pre-wrapped, which requires a different applicator gun, but this has made placement quicker and a one person job.
We always hear about the high and low pregnancy rates, but a good average on a timed AI program is 50 percent and higher. The time frames are critical – don’t synchronize more than you can possibly AI in three hours. Cows must be inseminated at the ideal time and all the AI protocols for handling, thawing and placing the semen must be followed.
As with any breeding program, cattle must be in good health, on a sound mineral and nutrition program and on a rising plane of nutrition at the time of breeding. All these things should help boost conception levels.
Strictly follow the protocols and handle cattle as gently as possible. It’s amazing the role stress plays in conception. I always double check my protocols and times to strictly adhere to the proper intervals.
Producers with questions should speak to their veterinarian, a semen representative or pharmaceutical rep with experience in these products.