Dumb question

[Hogfarmer10]

I've got a group of cows that will finish calving in about a week. After they get done, they'll be brought in and vaccinated/wormed/etc.
My bull won't be put back in until early January. My question is, if I go ahead and give all the girls a shot of lutalyse (with the hopes of tightening up the calving window), will the effects of the lutalyse last? I know it won't induce heat in all of them, but, in the ones that it does, will they remain somewhat synched until they are bred?

 

[Named'em Tamed'em]

Someone sharper than me will chime in I'm sure, but wouldn't it "reset" their clocks so to speak and get them going in sync.

 

[Lucky]

Interesting. Never thought of it this way.

 

[Son of Butch]

wouldn't it "reset" their clocks so to speak and get them going in sync.

That was also my gut reaction to the question, that a 'reset' would occur in the majority. But thinking about it deeper, I don't think that is true. "Artificially" inducing 1 egg to release early wouldn't change the timeline of the next egg's natural maturing and release. Though suppressing it could bring it more in line to achieve the desired result. Bottom line: I think there may be a minor benefit (a day or 2) in a small minority of females, but not nearly as great as my initial gut reaction.
As Lucky said, an interesting question.

 

[Hogfarmer10]

Thanks for your replies and opinions. You worded that perfectly- a reset. I hadn't considered the maturing of the next egg. I may just go with the whole 2 shots, 10 days apart closer to breeding. I really appreciate y'all always willing to share your wisdom and experiences with me.

 

[wbvs58]

When are you going to do this? How long after calving? For the PG to work the cows need to be cycling naturally, ideally 60 days after calving. Being during your winter some cows may have a prolonged anoestrus period. Spring with a good flush of new grass would be ideal. Cows that do come on heat with the PG should maintain that synch if they are not bred however the slighter variation in the cycle of the cows you will get a bit more divergence with each cycle. If you are successfull with synching them just watch out that you don't overload your bull.

Certainly not a dumb question.

Ken

 

[Hogfarmer10]

They started calving in August, majority calved September. There is only a few left- the heifers that I held from the bull an extra 6 weeks or so. I wouldn't give anything a shot of lute that was less than 45 days from calving, just the Aug/Sept/early Oct calving cows. I'm looking at working them sometime during the week of Nov 20.

 

[TCRanch]

When I started giving all my heifer calves Lutalyse at weaning (for potential abortions, not synching), I anticipated they'd all go into heat at the same time, but it didn't seem to make a difference. And I've been giving them Lute - in addition to pulling the bulls 6 weeks prior - for probably 6 years.

 

[Hogfarmer10]

That's interesting. I'm like you. I would have expected them to start cycling, at least part of them.

 

[simme]

Lutalyse only works IF the cow or heifer has a CL on an ovary. If a group of cows that are already cycling have randomly distributed heat cycles, about one third of them will not be affected by Lutalyse due to where they are in their cycle. Either they have recently cycled and do not yet have a CL or they are close to cycling anyway without the lutalyse. Once they cycle (with or without lutalyse), they will reset to that schedule. But since every cow will not be on an exact 21 day cycle, they will eventually spread back out.

If you are breeding with a bull, I would be concerned about having enough bull power to breed most of the cows in maybe a three day period. Unless you are running multiple bulls together. Seems like you indicated a single bull.

Is the goal to synch the cows November 20 while you are vaccinating in order to avoid working them again just prior to breeding?

You mentioned "tightening up the calving window". If the goal is to get more cows bred in 45 days or so, I don't see using lutalyse for that. My thoughts are that synching cows is for AI use to allow breeding most cows in a few days for convenience of the inseminator. For natural breeding, important issues are good nutrition and condition of the cows, fertile bull and a distributed (spread out) work load for the bull. If they are not synch'd, about 5% of the cows will be in heat each day for that first 21 day period -something the bull can handle. If they are synch'd in a 3 day window, 33% will be in heat each day - not good for a single bull. If they are not already cycling, lutalyse will not cause them to cycle.

Be aware of the effect of modified live vaccines given close to breeding. Might cause irritation/inflammation of the ovaries which results in less cows settled. November 20 vaccinations with mlv might affect breeding in early January.

In regard to lutalyse for heifers at weaning, it will mostly do its job for aborting the few that are bred. But, not likely to see most of the heifers in heat since majority will not be cycling at 7 or 8 months old - hopefully. Giving lutalyse will not cause them to start cycling. If not already bred or already cycling, the lut will not affect timing of future cycles.
That's my understanding and experience.

 

[Ky hills]

Years ago, an AI tech told me that he was going to give Lutalyse to his cows prior to turning a bull in with them. His logic was that even with natural service it should bring the cows to cycle closer together. I don't know how the results were, never asked or heard.
I would think that giving Lutalyse within a day or the day of turning them with a bull would bring more of them in within a few days. When we were AI breeding based on observed heat, we did two rounds of Lutalyse a week to ten days apart, I can't remember exactly and then started watching them after a day or two for signs of heat to breed. I would be concerned that if you went the 2 doses that too many depending on the cow to bull ratio would come in at the same time and some not get bred, and thus stretch out calving longer.
On a personal note, we have moved away from AI and Lutalyse and the like as we prefer a more natural non manipulative approach.
In my opinion I just like to have ours in good condition and access to a good quality mineral.

 

[Hogfarmer10]

Yeah. My goal was just to simply tighten up the calving window of this herd. My other 3 herds are all in about a 65 day window, and I'm satisfied with that. This herd, is at about 110-115 days. That just is too long. The vaccines that I will be using, the only one that is mlv just requires 4 weeks between injection and breeding. So if I hold until January 10th or so, I should be in good shape.
I will be using a single bull. There is only 38 cows in this group. Of those, half calved by sept 20, a big quarter calved by oct 20, and the remaining are finishing up now. My plan is to gather the early calving cattle and work them, then get the rest a week later. I do like to limit the amount of times they go through the chute, I especially don't want them associating that every time they go through the chute, they get jabbed or sprayed or new tags going in. I don't want them under the impression that chute = pain/discomfort. In fact, since I feed this herd in the barn that the chute is in, I often lock them up in the barn and then open the chute and let them go through it to get back out.
Also, my mineral program. February- March
they get high mag (they are turned out onto ryegrass pastures during this time)

April-September
Reproductive minerals with IGR + garlic, cinnamon

Oct -January
Reproductive minerals without fly control.

It's out in front of them 24/7, with consistent good intake. Does this sound like I'm doing ok with my mineral program?

 

[Travlr]

Yeah. My goal was just to simply tighten up the calving window of this herd. My other 3 herds are all in about a 65 day window, and I'm satisfied with that. This herd, is at about 110-115 days. That just is too long. The vaccines that I will be using, the only one that is mlv just requires 4 weeks between injection and breeding. So if I hold until January 10th or so, I should be in good shape.
I will be using a single bull. There is only 38 cows in this group. Of those, half calved by sept 20, a big quarter calved by oct 20, and the remaining are finishing up now. My plan is to gather the early calving cattle and work them, then get the rest a week later. I do like to limit the amount of times they go through the chute, I especially don't want them associating that every time they go through the chute, they get jabbed or sprayed or new tags going in. I don't want them under the impression that chute = pain/discomfort. In fact, since I feed this herd in the barn that the chute is in, I often lock them up in the barn and then open the chute and let them go through it to get back out.
Also, my mineral program. February- March
they get high mag (they are turned out onto ryegrass pastures during this time)

April-September
Reproductive minerals with IGR + garlic, cinnamon

Oct -January
Reproductive minerals without fly control.

It's out in front of them 24/7, with consistent good intake. Does this sound like I'm doing ok with my mineral program?

If your calving window is too extended you might try pulling your bull after sixty days and culling those not bred.

I'm not a fan of chemicals except in synchronizing for AI.

 

[Jeanne - Simme Valley]

I totally agree - put bull in for 60 days. That is the most reliable way to tighten your calving season.
As other said, grouping your cows most likely will EXTEND your breeding season = extending your calving season.

 

[Lucky_P]

Repro folks at UNL were recommending - a few years back - that if you had cows calving late in the season, and wanted to 'move them up', you could put in a CIDR at (no earlier than) 20 days post calving, and either just pulling them at 7 days or pulling and giving a shot of prostaglandin - Pull & Lutalyse (in my thought process) is primarily if the bulls are going in right then... but I'm not a reproductive specialist, and don't play one on TV.

4 tips for using CIDRs to move up late calvers

What’s the best method for moving late calving cows up in the breeding season? Consider these tips to tighten your calving window.

www.beefmagazine.com