gestation period and success rates of AI

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monkeywerkz

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We had our cow AI'd last fall (October 21st, to be exact). I had always thought that the gestation period of a cow was about 9 months. Is this correct? Our cow shows no sign of impending delivery. We just raise a few cattle for beef for our family, and this is the first time we have AI'd. I've never done anything with preg testing cows, either.

So how long do you think I'll need to wait? I get the feeling that she isn't pregnant and that we need to get her over to the bull. What are the rates of success with AI, and is it normal for a cow not to take when AI'd?

I am a long time reader, but just don't have the experience to post much. I have greatly enjoyed reading the comments, and have been helped many times. la4angus, dun and many others are a credit to this board, and that is why I still check daily.

Anyway, your help is appreciated.
 
monkeywerkz":1z84sudb said:
We had our cow AI'd last fall (October 21st, to be exact). I had always thought that the gestation period of a cow was about 9 months. Is this correct? Our cow shows no sign of impending delivery. We just raise a few cattle for beef for our family, and this is the first time we have AI'd. I've never done anything with preg testing cows, either.

So how long do you think I'll need to wait? I get the feeling that she isn't pregnant and that we need to get her over to the bull. What are the rates of success with AI, and is it normal for a cow not to take when AI'd?

I am a long time reader, but just don't have the experience to post much. I have greatly enjoyed reading the comments, and have been helped many times. la4angus, dun and many others are a credit to this board, and that is why I still check daily.

Anyway, your help is appreciated.

Gestation period for beef cattle is about 283 days, larger breeds may go longer, smaller breeds a shorter period. If she was bred, she should calve around July 30th.

A good AI tech, with good heat detection, will get 80-85% conception rate. But there are a lot of variables: was she in good condition, was she nursing a calf, did you do heat detection or a timed breeding? If you haven't seen her cycling since you AI-ed her, I'd think she was bred. Is her udder starting to get larger?

I hope she's bred for you. But you might consider if you don't have time to heat check on a regular basis, using a clean up bull after the cow has been bred AI. Good luck...
 
We had her to the vet, where he gave her shots to make her cycle and I think there was a type of implant that was used. Ten days later he removed the implant, gave her more shots, then AI'd her the following day (which was October 21). She was in good health, as far as we know.

She just isn't showing any signs of delivery. Her bag isn't growing. One day I'll look at her and think "wow, she is huge. She'll have this baby any day." The next day I'll look at her and think "I don't even think she is pregnant." It is like she is changing sizes.

I don't know whether this makes sense or not. Like I said, I am a beginner to this and just have a few cattle over the last few years for beef for our family, and this was our first experience with AI.
 
you might want to take her back to the vet to have her preg checked. or you can just wait a couple of weeks since she's so close to her due date.

some cows show no signs of approaching calving until a day or two before they calve while others will start springing & bag up way ahead of the due date.
 
If you did the AI yourself, and are new to it, success rates will probably be low. For the first 2 years of AI, I had about a 55% conception rate. They are getting better now, and hopefully be up to about 70% in a year. It gets better with practice.
Some cows will bag for over a month before they calve, and you always think...Damn, she can't get any more milk, and others barely show any signs and then just pop a calf out. Keep an eye on her, if you want, have the vet check her. But I would probably just wait a week and see what happens.
Did you put her with a clean-up bull? If you are just getting into AI, that is something you should consider having, so that this will not happen again. Has the cow shown any signs of heat since you AI'd her?
 
monkeywerkz":3ik9r9xd said:
We had her to the vet, where he gave her shots to make her cycle and I think there was a type of implant that was used. Ten days later he removed the implant, gave her more shots, then AI'd her the following day (which was October 21). She was in good health, as far as we know.

She just isn't showing any signs of delivery. Her bag isn't growing. One day I'll look at her and think "wow, she is huge. She'll have this baby any day." The next day I'll look at her and think "I don't even think she is pregnant." It is like she is changing sizes.

I don't know whether this makes sense or not. Like I said, I am a beginner to this and just have a few cattle over the last few years for beef for our family, and this was our first experience with AI.

Yes, it makes sense. The vet did a "timed breeding", not a natural heat breeding. More and more people are doing that. It makes it more convenient for the people, but I'm not sure your conception rates are as good. The only way to know for sure is to wait until her due date or get someone to palpate her to see if there's a calf inside. It's remarkable how different a cow will look before and after she gets a good drink. We AI all our cattle; I think Dun does, too. I have time to do heat checks several times a day during breeding season; not everyone has that luxury. AI is a great tool, but you have to be set up to make it work. Good luck...
 
We synchronize with CIDR's and horemone shots and use the fixed time breeding method and have had varried results from year to year, some good, some OK, but with the recip herd, all transfers are worked off natural heats

The wet weather this year in Texas has been BAD for working cattle, many have cycled and just didn't work to transfer, at least my tech was not going to risk embryos in cattle he was not sure would settle with a high degree of accuracy
 
Timed insemination runs around 60-65%, heat detected insemination should run in the 80% plus range. CIDRS aren't a magic bullet. Last year the neighbor used CIDRS in a bunch of Holstein heifers and time inseminated. For 3 days following the timed breeding I bred several heifers that came into standing heat. Of the ones I bred we got 100% of the timed ones, not counting those I bred, he ran about 60%. Semen and getting cows bred on time is way too important to me to mess around with the shots and timed insemination. But that's just an old pharts opinion.

dun
 
Gestation period for beef cattle is about 283 days, larger breeds may go longer, smaller breeds a shorter period. If she was bred, she should calve around July 30th.

Frankie you are partly right. The difference in gestation period is by cattle species. There is an gestation difference between bos indicus and bos taurus.... The part you got right is size difference in gestation period too....
 
greenpasture78":3lavlxj6 said:
Gestation period for beef cattle is about 283 days, larger breeds may go longer, smaller breeds a shorter period. If she was bred, she should calve around July 30th.

Frankie you are partly right. The difference in gestation period is by cattle species. There is an gestation difference between bos indicus and bos taurus.... The part you got right is size difference in gestation period too....

Actually size isn't the criteria. Hereford and Red Poll run about 189 (288 by the MARC study),limo 289, Branvieh 290, all the other continentals run 286-287 (MARC study) Angus is 283

dun
 
"Actually size isn't the criteria. Hereford and Red Poll run about 189 (288 by the MARC study),limo 289, Branvieh 290, all the other continentals run 286-287 (MARC study) Angus is 283"

Aren't Hereford and Red Poll moderate sized animals? They have a shorter gestation length. Continentals are larger and have longer gestation lengths according to your post. Why are you saying size isn't the criteria?

I have to disagree with 283 days for Angus, Dun. That's the table we use, but our Angus almost never go that long. Heifers are often two weeks early, and cows are generally less than 280 days. Our larger Angus, Max, Woodhill Valor cows, will run longer than our EXT cows. When we have a cow go the 283 days or longer, I start worrying and usually have good reason. We have an 8180 cow that had her first calf 18 days early. Her second calf was about two weeks early. It'll be interesting to see how she does this spring. Some people claim the bull has some influence in gestation length. I know people who say if they miss a cow on the first breeding, they'll breed her to GT Max because the calves will come early. That keeps the cow closer to the date he wanted her to calve with the first breeding. I suppose variations could be expalined by management, but we manage them all the same.
 
Frankie":2jqycm4g said:
"Actually size isn't the criteria. Hereford and Red Poll run about 289 (288 by the MARC study),limo 289, Branvieh 290, all the other continentals run 286-287 (MARC study) Angus is 283"

Aren't Hereford and Red Poll moderate sized animals? They have a shorter gestation length. Continentals are larger and have longer gestation lengths according to your post. Why are you saying size isn't the criteria?

I have to disagree with 283 days for Angus, Dun. That's the table we use, but our Angus almost never go that long. Heifers are often two weeks early, and cows are generally less than 280 days. Our larger Angus, Max, Woodhill Valor cows, will run longer than our EXT cows. When we have a cow go the 283 days or longer, I start worrying and usually have good reason. We have an 8180 cow that had her first calf 18 days early. Her second calf was about two weeks early. It'll be interesting to see how she does this spring. Some people claim the bull has some influence in gestation length. I know people who say if they miss a cow on the first breeding, they'll breed her to GT Max because the calves will come early. That keeps the cow closer to the date he wanted her to calve with the first breeding. I suppose variations could be expalined by management, but we manage them all the same.

Red Poll and Herefords are about the same size as Angus. Although the tables show 283 for Angus, the 283 I stated was also from the MARC study.
Our Red Angus sired calves are usaully right at 283-284 days. But heifers it's alwasy a crapshoot. We've found that generally if calves come early from a couple of cows/heifers that the majority of them will be early, late works the same way. Although this year we had them everywhere from 14 days early to 13 days late. But the majority were right at 283-284, even the Hereford sired calves.
Also, it seems that calving ease bulls tend to have slightly shorter gestation then the larger birth weight bulls. But that's just anecdotal, I've never seen a study, just what seems to be the case for us.

dun
 
My grandpa always said that if they are late the calf will be a bull. He says it takes longer for the outdoor plumbing! :) :)
 
We have used CIDR's with much higher success than other have mentioned

We do use heat detection, AM and breed in the PM, if we don't see a good standing heat and a busted K-MAR, we don't breed them, also semen Quality plays a huge role in conseption rates

We use a microscope to check semen quality on bulls we have not used before, if the semen is all dead or poor quality you will get 0% conseption rates, always check it if you have the means to do so, it will save time and lots of $ and frustration
 
If you know any local herdsman that are trained in preggin a cow they can help you see if she is, plus they are usually free unlike a vet. If you're worried throw her in w/ a cleanup bull and be done w/ it. if she's bred its ok, if not, you'll get her done.
 
The technician that a.i's my cows prefers to breed them 20 hours after I see them stand - if I see her stand at 9 p.m he will add 8 hrs to 9am - and breed around 5 p.m the following day. He likes to wait atleast 60 days after she has calved. This does seem to get them bred on the first try.
 

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