Advice for AI on some heifers

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Jeanne - Simme Valley

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Many people have # hours after "first" standing. I have been AI'ing for 50 years, I basically use the am / pm rule. First 2 weeks of breeding, I will try to breed as early as I dare - shooting for more heifers, but when you breed early, you take the chance of dam not releasing her egg too late. Later breeding tends to be more chance of pregnancy.
 

JKCattle

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Just need to remember that maximum life span of semen in the cow is 24 hours and the ovulated ovum is about 18 hours, although beyond 12 hours, fertility of both declines rapidly. Ovulation occurs about 10-12 hours after end of standing heat. We try AM / PM on our cows, but keep in mind above facts and breed by what our schedule allows. If we think something is not right with a heat we either breed early with a shot of GnRH or breed twice (AM and PM).
 

Angusjohn

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Heifers tend to have a shorter cycle. Mine usually cycle average 18 days and cows 21 days. So, they generally respond faster to a PG shot (like 1-3 days and cows 2-5 days)
Heat detecting and breeding natural heats for 5-6 days, then PG shot everything not bred is the cheapest sync program and it works - IF AND ONLY IF - they are already cycling. PG will only work if they have a CL. CIDRs will make a cow cycle if she hasn't been, BUT, it is not necessarily a good viable heat.
Is your comment on CIDRs and cows based on your A.I. experience (extensive) or university research? This is a question I have asked of our extension service Agent. He tells me research indicates no difference in conception rates on natural versus synced heats. I always use CIDRs, just because of the lack of time to obreve. Some years, run 80% to the AI, other years in the mid 60s.
 

Gonz

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am/pm rule is fine for heifers if you are going off observed heats. If you are doing timed AI the timing makes a big difference. Ranges from 54 to 72 hours after PG depending on protocol. WB's protocol above is the best one ever for timed AI on heifers.
 
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Josher

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We’ve done 13 out of a group of 37 heifers. I’ve found the opening of the cervix was harder to find than on cows but not impossible. A lot less variations heifer to heifer vs cows. Hope they catch. Been using fertagyl at breeding on anything that’s questionable on timing or ones that have gotten PG. Starting to Ai cows now. Bye bye spare time lol.
 

Nkline

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We’ve done 13 out of a group of 37 heifers. I’ve found the opening of the cervix was harder to find than on cows but not impossible. A lot less variations heifer to heifer vs cows. Hope they catch. Been using fertagyl at breeding on anything that’s questionable on timing or ones that have gotten PG. Starting to Ai cows now. Bye bye spare time lol.
What are you hoping to gain that a bull can’t provide. I use AI on some heifers and ET just to try out or bring in new genetics. I only do this in my purebred herd, my AI calves typically don’t sell for more than calves out of my home raised bulls.
 
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Josher

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What are you hoping to gain that a bull can’t provide. I use AI on some heifers and ET just to try out or bring in new genetics. I only do this in my purebred herd, my AI calves typically don’t sell for more than calves out of my home raised bulls.
Well to sum it up. Had a bull go down at a bad time and had to change plans where bulls went in pastures and instead of buying another heifer bull I just pulled out some heifers of the main group to AI. Most of these heifers will be sold as breds but I figure it might add some value to them. Bred to high accuracy proven calving ease bulls.
 

Nkline

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Well to sum it up. Had a bull go down at a bad time and had to change plans where bulls went in pastures and instead of buying another heifer bull I just pulled out some heifers of the main group to AI. Most of these heifers will be sold as breds but I figure it might add some value to them. Bred to high accuracy proven calving ease bulls.
Sounds like a good reason. Especially since you’re selling breds.
 

W.B.

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I think there are a lot of reasons to ai yearlings especially if you are keeping replacements. Yes I get it that there are a lot of bulls in the studs are are not especially good but choose a proven calving ease bull that has daughters in production and your herd quality goes up. You can really focus on the little Things like udder quality and disposition.
 

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