Induced cycling and reduced fertility

[angus9259]

I've come to understand that inducing cycling can result in reduced fertility on the first heat following the "induction". Is that true if the cow is already cycling and you just manipulate the timing or is it only true of attempting to induce cycling itself post calving in order push cows into cycling?

 

[novaman]

Natural heats will almost always be more fertile than induced heats. The difference in fertility may be minimal if the cows are in good condition with low levels of stress.

 

[bigag03]

Any cow's first heat postpartum will have reduced fertility whether it is natural or induced. In cows that are in good shape and cycling, I have never experienced lower fertility just because of heat synchronization. However, if cows are not cycling for any reason (nutrition, post partum interval, health, etc.), then, yes, an induced heat will have lower fertility.

 

[cow pollinater]

first heat following the "induction".

Am I correct in thinking that you mean the return to estrus twenty one days after syncronization and A.I. or do you mean the estrus that is the direct result of syncronization? If you mean the return to estrus three weeks after syncronization, it's only associated with cidr inserts as far as I know and some would say that they work so well that only infertile cows get a second service thereby making the second service look poor. I haven't messed with them enough to have a strong opinion on them.

 

[dun]

Based strictly on the 60% average for AI for induced heat I would think that there probably is some reduction in fertility. The few times we've done shots to induce heat the only one that's ever settled to that service was Granny. None of the others, maybe a half dozen through the years, have settled on that service but settled on the following natural heat

 

[angus9259]

first heat following the "induction".

Am I correct in thinking that you mean the return to estrus twenty one days after syncronization and A.I. or do you mean the estrus that is the direct result of syncronization? If you mean the return to estrus three weeks after syncronization, it's only associated with cidr inserts as far as I know and some would say that they work so well that only infertile cows get a second service thereby making the second service look poor. I haven't messed with them enough to have a strong opinion on them.

My understanding is that the more infertile estrous is the one directly associated with syncronization - that if you wait the 21 days following, the conception rate goes way up. My question, then, is if a cow is already cycling normally and you simply syncronize and don't initiate (as gnrh and cidrs can be used for) is that estrous directly associated with the hormones still less susceptible to conception?

 

[cow pollinater]

My question, then, is if a cow is already cycling normally and you simply syncronize and don't initiate (as gnrh and cidrs can be used for) is that estrous directly associated with the hormones still less susceptible to conception?

Shouldn't be. The drugs don't really force the cow to cycle. They give her ques through the bloodstream that tell her when to do certain things that (if she is cycling) she's already doing for herself. If you see a heat as the result of drugs it should be just as fertile as a natural heat.
The lower fertility associated with ovsync and other sync programs is due to their ability to cycle cows that nature is not ready to cycle and in some cases drug misuse/failure.
If you breed nine cows on natural cycles and number ten goes to the bull without being bred because she didn't show you a heat, your conception should look pretty good. If you sync that same bunch of cows, that last cow will drag down the average. Yes, you made her cycle and yes, she may show up pregnant but it's not as easy as it is with cycling cows so in the long run the average conception goes down.
As far as the drugs are concerned, they are synthetic versions of what happens within the cow. Ask your pharmacist or doctor if every synthetic drug/hormone works the same on everyone and see what they say...

 

[angus9259]

My question, then, is if a cow is already cycling normally and you simply syncronize and don't initiate (as gnrh and cidrs can be used for) is that estrous directly associated with the hormones still less susceptible to conception?

As far as the drugs are concerned, they are synthetic versions of what happens within the cow. Ask your pharmacist or doctor if every synthetic drug/hormone works the same on everyone and see what they say...

Funny . . . already know the answer to that one. There have been a couple threads on this site about that and the opinions vary widely. Thanks for the feedback.

 

[cow pollinater]

The take-home message from my long winded reply was that if you see physical signs of estrus, the cow really is in estrus and fertility on that particular cow won't be reduced.