Fertility?

[vclavin]

The following question is based on AI done with sequencing and/or using AI drugs of any kind.

I'm not so sure females that take first time AI consistently are necessarily more fertile, due to the possible need for the AI drugs to get pregnant. I say this as the vet mention that older cows and higher BCS produce less hormones and that makes it harder to get them settled. If you use hormones on them to get them AI"d, there's no true way to know if the animal "required" the hormones or was capable of getting settled via bull consistently without aid of hormone injections.

Your thoughts please.

Valerie

 

[Lucky_P]

Val,
The 'hormones' you allude to are not 'required' for AI - but are used in synchronization programs, in order to manipulate the cow or cows' estrus cycle so that:
1. we can inseminate at a time that best suits US, or,
2. all animals in a group are synchronized to come into heat at essentially the same time, so that we can concentrate heat-detection and insemination efforts into one small timeframe - and as a result, have all calves delivered in a close window - leading to more uniform growth of the calf crop.

The 'hormones' - gonadotropin-releasing hormone(GnRH), prostaglandins, and/or progesterone-impregnated CIDRs - are used at levels that really have no impact on fertility(actually, only the progesterone might have an effect + or - on fertility, if used at higher levels), but merely manipulate the timing of the cycle.

Yes, you'll have some folks who'll claim that the next estrus AFTER a synchronized cycle is 'more fertile' than the synchronized cycle - but that's anecdotal BS with no proof to back it up.

 

[TexasBred]

IN my mind success or failure in an AI breeding program is more dependent on the human side of the equation than the cow. She's done her part. Now it's your time to get the sperm where it needs to be at the time that it needs to be there. You may have one that doesn't settle but when half the herd doesn't settle don't blame the cattle.

 

[vclavin]

Guess I'm not making myself clear on this.

There are some cows that have a better chance of getting settled due to AI drugs being used. We know those drugs can bring non cycling cows into cycling, it just seems that maybe some of those cows may appear more fertile ONLY because these drugs have been used.
I have a cow or 2 that settle better to AI than they do to the bull.
Does that make better sense?
Valerie

 

[RD-Sam]

Guess I'm not making myself clear on this.

There are some cows that have a better chance of getting settled due to AI drugs being used. We know those drugs can bring non cycling cows into cycling, it just seems that maybe some of those cows may appear more fertile ONLY because these drugs have been used.
I have a cow or 2 that settle better to AI than they do to the bull.
Does that make better sense?
Valerie

Chances are they are your best cows if they are easy to make cycle with drugs. If they aren't in good condition there probably isn't enough hormones in the world to make them cycle. It just boils down to proper management and selecting the best cows.

 

[hillsdown]

Guess I'm not making myself clear on this.

There are some cows that have a better chance of getting settled due to AI drugs being used. We know those drugs can bring non cycling cows into cycling, it just seems that maybe some of those cows may appear more fertile ONLY because these drugs have been used.
I have a cow or 2 that settle better to AI than they do to the bull.
Does that make better sense?
Valerie

Do you use FSH too, or just prostaglandin and gnrh when inducing ?

We haven't induced for a few years, just heat check and breed as many as we can before we throw them out to pasture with the clean up bull. Think I will have to sync again next year as I pushed my calving dates back (hubby's ankle screwed my season up) and will only have a week or so before they will get tossed out to pasture. Don't know how I will be able to pen them and breed them if they are over there. I do know I will never again do timed AI breeding without seeing an actual heat. Have had no luck with that whatsoever. :help:

 

[Lucky_P]

val,
I understood your point - I just don't think, from a physiologic standpoint, that it's valid. None of the hormones that we use in a typical synchronization protocol enhance or diminish fertility - they just alter/confine timing of estrus and ovulation.

However, in some instances, not adhering to proper timing of CIDR removal, etc., can be detrimental to conception rate on a given cycle - if CIDRs are left in beyond 7-8 days, degenerative aging of the oocyte that is 'in the pipeline' for maturation can occur - yielding a lowered conception rate on that breeding.

 

[novatech]

I ben looking but can't find a cow that read the book. :lol2:

 

[cow pollinater]

The faster we can get cows cycling the faster we can get them pregnant, even though that might not mean them getting pregnant right away(as in we can force them to cycle but we can't force them to concieve). Syncronizing cows gets all of them cycling but it will consistantly be the cows that are ready to go that settle first so anything that concieves via synchronization should be considered to be a fertile cow. Anything that settles faster because of the drugs doesn't really have a problem, they just got help they didn't really need.
As far as some cows sticking better AI, the cows estrus cycle is not one size fits all. We know the timing of events in the AVERAGE cows cycle but it imposible to say that what we think will happen will indeed happen with every cow every time and within the same time frame... If, for example, A cow were to ovulate earlier in her cycle than what we're used to seeing, it would make sense that AI would have a better chance of impregnating that particular cow since semen is deposited further into the reproductive tract which would make more viable semen available at the point of best fertility.

 

[cow pollinater]

If, for example, A cow were to ovulate earlier in her cycle than what we're used to seeing, it would make sense that AI would have a better chance of impregnating that particular cow since semen is deposited further into the reproductive tract which would make more viable semen available at the point of best fertility.

Now that I think about it, I guess a case could be made for AI leading to infertility since in this case it would allow a cow that was at a natural disadvantage to reproduce... Just what I needed, something else to ponder over. :cry2:

 

[vclavin]

If, for example, A cow were to ovulate earlier in her cycle than what we're used to seeing, it would make sense that AI would have a better chance of impregnating that particular cow since semen is deposited further into the reproductive tract which would make more viable semen available at the point of best fertility.

Now that I think about it, I guess a case could be made for AI leading to infertility since in this case it would allow a cow that was at a natural disadvantage to reproduce... Just what I needed, something else to ponder over. :cry2:

Just what I was wondering. If a cow is not cycling on time, what do we do? Give her shots and if she settles we call her fertile...hmmmm
Valerie

 

[cow pollinater]

If, for example, A cow were to ovulate earlier in her cycle than what we're used to seeing, it would make sense that AI would have a better chance of impregnating that particular cow since semen is deposited further into the reproductive tract which would make more viable semen available at the point of best fertility.

Now that I think about it, I guess a case could be made for AI leading to infertility since in this case it would allow a cow that was at a natural disadvantage to reproduce... Just what I needed, something else to ponder over. :cry2:

Just what I was wondering. If a cow is not cycling on time, what do we do? Give her shots and if she settles we call her fertile...hmmmm
Valerie

The cow in my example would most likely not respond to syncronization very well since syncronization was designed to fit the average cow's cycle.

 

[cow pollinater]

The cow in my example would most likely not respond to syncronization very well since syncronization was designed to fit the average cow's cycle.

Now that I think about it, the cow with the particular problem in my example would actually heavily favor syncronization and AI since we would be able to correct her time of ovulation and impregnate her despite the flaw and possibly carry the trait on to future generations.

I can't say that I agree with you but I have to admit that in my own example you may be on to something.

 

[TexasBred]

CP I think you've confused yourself. You want to synchronize her to correct the "non cycling" , impregnate her despite the "flaw" and carry that trait forward??? I"m lost....course we never synch'd anything either. Just observed heats but AI'd everything.

 

[vclavin]

Now you understand what I'm getting at....
Valerie

 

[novatech]

There are other reasons other that low fertility that cows will not settle with AI. Mine always got a chance with the bull before they were culled.

 

[vclavin]

There are other reasons other that low fertility that cows will not settle with AI. Mine always got a chance with the bull before they were culled.

Novatech,
The point is whether we are or are not promoting infertility by using drugs that sort of "make" them fertile in certain situations.
Valerie

 

[novatech]

There are other reasons other that low fertility that cows will not settle with AI. Mine always got a chance with the bull before they were culled.

Novatech,
The point is whether we are or are not promoting infertility by using drugs that sort of "make" them fertile in certain situations.
Valerie

My experience is the other way around. A cow that doesn't take a bull doesn't AI either. The drugs cannot make an infertile cow fertile. They take what is there and change the timing. Other than getting rid of a cyst, what kind of drugs are you speaking of? It is my understanding that you first must have a cow that is cycling so you can re-time the cycle to fit you program. I'm not a vet but I don't know how any normal protocol or commonly used drug can get a cow that does not cycle to start cycling. So if you plan on telling me that one does please explain how. I'm not trying to be argumentative just trying to learn some I may not be aware of.

 

[vclavin]

There are other reasons other that low fertility that cows will not settle with AI. Mine always got a chance with the bull before they were culled.

Novatech,
The point is whether we are or are not promoting infertility by using drugs that sort of "make" them fertile in certain situations.
Valerie

My experience is the other way around. A cow that doesn't take a bull doesn't AI either. The drugs cannot make an infertile cow fertile. They take what is there and change the timing. Other than getting rid of a cyst, what kind of drugs are you speaking of? It is my understanding that you first must have a cow that is cycling so you can re-time the cycle to fit you program. I'm not a vet but I don't know how any normal protocol or commonly used drug can get a cow that does not cycle to start cycling. So if you plan on telling me that one does please explain how. I'm not trying to be argumentative just trying to learn some I may not be aware of.

I had understand the sequencing drugs would start the cycling even in non cycling females... like before the 45 days after calving and in non cycling heifers.
Valerie

 

[vclavin]

The system for controlling estrus in groups of cows could be beneficial as part of a total system to manage for a high reproductive rate in large herds.


Got htis from the following url at the conclusion of test.
http://www.sciencedirect.com/science/article/pii/S0022030272855425

Seems to me they are increasing reproduction by using the drugs. Maybe theres a distinction between fertility and high reproduction? Always considered them the same thing, maybe there a two seperate traits.
Valerie