What are the opening hours?

Saturday 9am - 5pm Sunday 9am - 5pm

Linessa Farms, LLC, 2563 N McKinley Avenue, Rensselaer, IN (2026)

06/19/2026

Breeding on a Calendar - Article 8: PG600 and Gonadotropins

PG600 gets talked about a lot in small ruminant breeding protocols, and if you're new to these protocols, you're going to see it come up a lot.

This is especially true when people are trying to breed out of season, synchronize groups, tighten timing, or improve ovarian response.

But... PG600 can be misunderstood.

Some people talk about it like it's the same kind of tool as Lutalyse, and it's not. For those of you who have been following this series, it should make sense.

- Lutalyse and prostaglandins are aimed at the corpus luteum.
- They are used to remove a natural progesterone source when a responsive CL is present.

PG600 is different. PG600 is a "gonadotropin product".

That means its main job is to stimulate ovarian activity.

To keep the categories clean:

*Lutalyse/prostaglandin: remove the progesterone brake.*

*PG600/gonadotropins: "push" ovarian activity forward.*

- What are gonadotropins? -

Gonadotropins are hormones that act on the go**ds, and in females, that means the ovaries.

The two big terms people hear are:

- FSH
- LH

FSH stands for follicle-stimulating hormone.

LH stands for luteinizing hormone.

You don't need to get bogged down in the abbreviations. Just think of them this way:

- FSH supports follicle growth.
- LH supports final maturation, ovulation, and luteal development.

In a natural cycle, the brain and pituitary help coordinate those signals.

- The brain sends reproductive messages.
- The pituitary releases gonadotropins.
- The ovaries respond.
- Follicles grow.
- Estrogen rises.
- Estrus behavior may become visible.
- Ovulation can follow.

PG600 is used because "it brings gonadotropin-type stimulation" into the conversation.

- What PG600 is trying to do -

PG600 contains two types of hormone activity.

- One part acts more like an FSH-type signal.
- One part acts more like an LH-type signal.

In plain language, PG600 is trying to give the o***y a stronger push.

"That push may help support follicle development, follicular maturation, ovulation, or synchronization response depending on the animal, season, protocol, and timing."

That's why PG600 often shows up in protocols where the female may need more ovarian stimulation.

- Out-of-season breeding.
- Transition periods.
- Animals that are not showing strong natural cyclicity.
- Groups being prepared for timed breeding or AI.
- Situations where the protocol is trying to tighten the response after progesterone withdrawal.

- CIDR, Lutalyse, and PG600 are doing different jobs -

This is where the earlier articles start connecting (hopefully).

1. A CIDR provides a temporary progesterone signal (it helps hold the system). When the CIDR is removed, the artificial progesterone signal drops.

2. If the female also has a functional CL, Lutalyse or another prostaglandin may be used to regress that CL so the natural progesterone source drops too.

3. PG600 is doing something different (it is the ovarian push).

Three tools, three different jobs, and one coordinated attempt to control timing.

- The o***y still has to be able to respond -

PG600 is a signal... but a signal only works if the o***y can respond to it.

If the animal is in good body condition, under "decent" management, near enough to reproductive readiness, and the protocol timing makes sense, the o***y may respond well.

If the animal is thin, sick, heavily parasitized, heat-stressed, severely out of season, still recovering from lactation, mineral-deficient, or metabolically strained, the response may be weaker or less predictable.

That doesn't always mean PG600 did “nothing.”

It may just mean the system was not prepared to respond well.

A louder signal does not fix a broken receiver.

Gonadotropins can push the o***y, but they can't make the whole animal ready by themselves.

- Dose matters -

This is where people can get themselves in trouble.

It is tempting to think:

"If some PG600 helps, then more should work better.”

That's not good biology.

The o***y is living tissue with follicles at different stages, hormone receptors, feedback loops, and a limited ability to respond appropriately. Needless to say, a lot is going on.

- Too little stimulation may not give the desired response.
- Too much stimulation can also create problems.

So, more is not automatically better.

- More can mean follicles are pushed too hard or at the wrong time.
- More can mean a less natural hormone environment.
- More can mean a response that is LESS synchronized, not more synchronized.
- More can mean ovulation numbers the female or the management system cannot support.
- More can mean higher cost without better pregnancy results.

That's also why embryo-transfer and superovulation programs often use carefully timed gonadotropin schedules instead of one giant “more is better” dose (some don't use PG600 at all, but that's another story).

The goal is not to shock the o***y.

The goal is to support a group of follicles through development in a controlled way.

In those programs, the schedule IS part of the dose.

A large single push may not create the same follicular environment as smaller, timed signals.

*Your veterinarian/breeding specialists often have different time schedules and dosages based on your specific breed and what it is that you're doing/goal.*

- Species matters.
- Breed matters.
- Season matters.
- Body condition matters.
- Cycling status matters.
- The goal matters.

Natural service is not the same as timed AI, and timed AI is not the same as LAI. Synchronization is not the same as embryo-transfer donor work.... so on and so forth.

So when someone asks me, “How much PG600 should I use?” the honest answer is:

That depends on the protocol, the animal, the season, the goal, and veterinary guidance.

The better question is:

What ovarian response are we trying to create, and is this animal ready to respond appropriately?

Full disclosure: When we have our veterinarian perform LAI, they give us a detailed sheet with instructions. I don't deviate from the sheet. I make the assumption these guys and gals know what they are doing. These folks have enough time, resources, and evidence-based practice to know what to do and when to do it for the best overall outcomes.

- Can PG600 increase multiples? -

This question comes up because PG600 can support follicular activity.

If more follicles develop and ovulate, the potential for more embryos exists.

But it is not as simple as saying:

“PG600 equals more babies.”

"Ovulation rate is influenced by breed, genetics, season, body condition, nutrition, age, previous reproductive history, and protocol timing".

- Some animals may respond strongly.
- Some may respond modestly.
- Some may not respond much at all.

And more ovulations do NOT guarantee more live lambs or kids, so try not to get hung up on the idea "more eggs automatically means more lambs or kids".

The goal should be a reproductive response the animal and the farm can actually support.

- The practical lesson -

PG600 is a gonadotropin product used to stimulate ovarian activity.

If progesterone is the brake, and Lutalyse helps remove the natural brake from the CL, then PG600 is more like a push on the ovarian gas pedal.

But... the engine still has to run, and the animal still has to be ready enough to respond.

The o***y still needs to be capable of developing follicles, producing hormones, ovulating, and supporting the next steps.

- Next in the series: -
Article 9 - Standing Heat, Silent Heat, and Ovulation

We will separate what we see from what the o***y is actually doing: why standing heat is behavior, ovulation is an ovarian event, and why those two things don't always line up perfectly.

06/17/2026

Breeding on a Calendar - Article 7: Lutalyse and Prostaglandins

I've posted a few videos recently talking about this, but I know a lot of you save the articles.

Lutalyse is one of those products people mention quite a bit when talking about breeding protocols.

“Give Lutalyse.”

“Did you lute them?”

“Use prostaglandin.”

“She needs a shot to bring her in.”

But if we're going to understand controlled breeding, we need to be careful with the language.

Lutalyse does not simply “bring females into heat.”

That is the shortcut explanation.

The better explanation is this:

Lutalyse helps remove a natural progesterone source when a responsive corpus luteum is present.

That may sound more complicated, but it is much more accurate, and once you understand progesterone, this will make a lot more sense (hopefully).

- The corpus luteum is the target -

Progesterone is the holding signal.

A CIDR adds a temporary progesterone signal.

But... the female may also have her own natural progesterone source.

That source is the corpus luteum, often referred to as the "CL".

The CL forms on the o***y after ovulation, and its job is to produce progesterone.

- As long as the CL is active, progesterone stays elevated.
- As long as progesterone is elevated, the reproductive system is being told:

"Hold still. Do not start over yet"

That's why the CL matters.

If a female has a functional CL, she has a natural source of progesterone inside her body.

- Prostaglandin removes the hold -

Lutalyse is a prostaglandin product.

More specifically, "it contains dinoprost, which has prostaglandin F2-alpha activity".

Other products (such as estrumate) may use different prostaglandin analogs, but the basic reproductive idea is similar.

Prostaglandins act on a responsive CL and cause it to regress.

That regression is called "luteolysis".

Luteolysis basically means breakdown or regression of the corpus luteum.

- When the CL regresses, progesterone drops.
- When progesterone drops, the hold signal is removed.
- Then the reproductive system can move toward the next heat and ovulation.

So the real sequence is:

Functional CL → prostaglandin → luteolysis → progesterone drops → system can move toward estrus

That is different from saying:

“Lutalyse causes heat.”

It is more accurate to say:

"Lutalyse removes the progesterone brake if the animal has a responsive CL".

- It only works if the target is there -

This is the part people miss.

- Prostaglandin is not working on an empty o***y.
- It is not creating a cycle from nothing.
- It needs a target.

That target is a functional, responsive CL.

- If the female has not ovulated, she may not have a CL.
- If the CL is too young, it may not respond the same way a mature CL would.
- If the female is truly anestrous and not cycling, there may not be a CL to regress.

If she's pregnant, the consequences can be SERIOUS because progesterone may be supporting that pregnancy.

This is why timing matters (a lot).

- Why protocols combine CIDRs and prostaglandins -

This is where synchronization starts to make more sense.

- A CIDR adds a controlled progesterone signal.
- A functional CL produces natural progesterone.

If we remove the CIDR... but the animal still has a CL producing progesterone, the body may still be receiving a hold signal.

So some protocols include prostaglandin to remove that natural progesterone source.

In simple terms:

- CIDR: adds a controlled progesterone signal.
- Lutalyse/prostaglandin: removes a natural progesterone source from the CL.

Those are different jobs, but they're part of the same strategy.

The protocol is trying to control progesterone from two directions:

the artificial source (CIDR) and the natural source (CL).

- Prostaglandin is not PG600 -

This is another source of confusion for some folks.

PG600 and prostaglandin are not the same thing.

They both have “PG” floating around in conversation, but they are doing very different jobs.

PG600 is a gonadotropin product.

It is used for a different purpose, involving ovarian stimulation and follicular/ovulatory signaling.

We'll get into that later (in the next article).

- Why “more” is not automatically better or needed -

Because prostaglandin has a specific target, more product is not automatically better science.

- If the CL is responsive, the goal is luteolysis.
- If there is no responsive CL, increasing the dose does not magically create one.

If the animal is pregnant, the concern is not whether the shot “worked.", the concern is that removing progesterone support may compromise pregnancy.

This is why protocols, labels, veterinary direction, species, timing, pregnancy status, and withdrawal considerations matter. Many veterinarians will have a detailed schedule for you to follow based on your specific animal (especially when you are looking at AI/LAI).

- Why some females show heat after Lutalyse -

When prostaglandin successfully regresses the CL, progesterone drops, and that drop allows the reproductive system to move toward the next follicular phase.

- Follicles can continue developing.
- Estrogen can rise.
- Behavioral heat can become visible.
- Ovulation can follow.

So yes, a female may show heat after Lutalyse, just don't confuse that by assuming it's a "heat hormone". The heat happens because progesterone falls and the system is allowed to move forward.

- The pregnancy warning -

I've already mentioned this multiple times, but this article would be incomplete without saying this one more time directly.

Prostaglandins can be dangerous in pregnant animals!

If a pregnancy is dependent on progesterone support from the CL, causing CL regression can result in pregnancy loss.

The same tool that'll reset a cycle can also remove the hormone support needed to maintain pregnancy.

That is why prostaglandins need to be handled with respect.

- The practical lesson -

- Lutalyse and similar prostaglandins are not fertility shots.
- CIDRs add a controlled progesterone signal.
- Prostaglandins remove a natural progesterone source.

Hopefully, as we are rolling along through this series, the steps you take and drugs you give to control breeding are starting to make more sense.

Next in the series:
Article 8 - PG600 and Gonadotropins

We'll look at why PG600 is very different from Lutalyse, what gonadotropins are trying to stimulate, and why ovarian response depends on more than just giving “the shot.” And of course, my favorite topic when talking about PG600.... more is not better.

06/15/2026

3 CL’s Doesn’t Equal 3 Babies

06/09/2026

Basic pregnancy in sheep and goats and why we use CIDR’s, Prostaglandins, and PG600

06/04/2026

Breeding on a Calendar - Article 6: CIDRs

A CIDR makes a lot more sense if we understand progesterone, and that's why we talked about progesterone before we talked about the device. If you haven't read Article 5, I would consider going back and reading it first.

A CIDR is a tool used to temporarily control one major hormone signal:

progesterone

- What is a CIDR? -

CIDR stands for Controlled Internal Drug Release.

In sheep and goats, it's an intravaginal device used in many controlled breeding and synchronization programs.

The basic idea behind a CIDR is simple:

- A CIDR provides a controlled progesterone signal.
- That progesterone signal tells the reproductive system:

*Hold still for now*

That's the same general job progesterone does naturally after ovulation when the corpus luteum, or "CL", is producing progesterone.

- Progesterone is the pause -

In the last article, we talked about progesterone as the holding signal.

- Progesterone rises after ovulation because the CL produces it.
- While progesterone is high, the female usually does not show a normal heat.

The body is being told:

- We may be pregnant.
- Do not start over yet.
- Hold this phase.

When progesterone drops, that holding signal is removed, and the reproductive system can move toward the next opportunity for estrus and ovulation.

This rise and fall is the rhythm synchronization programs are trying to manage.

*A CIDR gives us a way to influence that rhythm*

- Insert, hold, remove -

When a CIDR is INSERTED, it exposes the female to a controlled progesterone signal, and that helps place animals under a similar “hold” signal for a period of time.

Then, when the CIDR is REMOVED, that artificial progesterone signal drops.

*The drop is the important part*

The system has been held under progesterone influence... then the hold is removed.

The female’s reproductive system can begin moving toward estrus and ovulation in a more predictable window.

That's the logic behind the CIDR.

*Insert: hold the system.*

*Remove: release the system.*

So... you can think of CIDR's as "timing tools".

- The device does not do the whole job -

A CIDR can help control a progesterone signal, but the animal still has to do the biology.

- Follicles still have to develop.
- Hormone signals still have to coordinate.
- Estrus still has to occur.
- Ovulation still has to happen.
- Semen still has to be placed at the right time.
- Fertilization still has to occur.
- Early pregnancy still has to be supported.

You get the point... that's why the same CIDR protocol can produce different results in different animals.

The device only influences one major signal.

It does NOT make every female's response biologically identical.

- Removal matters -

A lot of people focus on putting the CIDR in, but removal is just as important (maybe more important).

The reproductive system is not only responding to progesterone being present.

*It is responding to progesterone being withdrawn*

That withdrawal tells the system:

"The hold is gone. Now things can move forward."

That's why timing around CIDR removal matters so much in breeding protocols.

The device matters, but the hormone pattern matters more.

- What about the animal’s own CL? -

This is where CIDRs and prostaglandins start to overlap.

A female may already have a natural CL, and if she does, that CL might already be producing progesterone.

So... even if the CIDR is removed, the animal may still have another progesterone source inside her body.

This is one reason some protocols include Lutalyse or another prostaglandin product (more on Lutalyse in the next article).

- The CIDR provides a temporary progesterone signal.
- The prostaglandin can be used to regress a responsive CL so the animal’s own progesterone source drops too.

Those are different jobs.

- CIDR: adds a controlled progesterone signal.
- Prostaglandin: can remove a natural progesterone source from the CL.

That is why protocols sometimes include both... basically, we are trying to control progesterone from two directions:

the artificial source AND the natural source.

- In-season and out-of-season are not the same -

A CIDR may be used during the normal breeding season, during transition periods, or as part of out-of-season breeding strategies.

In season, the animal’s reproductive system may already be moving in the right direction, and the CIDR may mainly help organize timing.

Out of season, the system may be quieter, follicular activity may be weaker, the brain-o***y conversation may not be as strong.... so on and so forth.

That's why you often see out-of-season protocols involve more pieces.

- Melatonin.
- Light manipulation.
- Ram or buck effect.
- Flushing.
- Gonadotropins like PG600 or eCG-type products.
- Prostaglandins.

All these different tools are used because they are trying to solve different biologic problems.

A CIDR is just one piece of the puzzle.

It does NOT automatically make an out-of-season animal function like she is in peak breeding season.

- CIDRs and visible heat -

CIDR removal may help bring a group of females into a more predictable estrus window.

But... the visible heat can still vary. Some females might show a strong/obvious standing heat, and you might have a few odd balls that don't.

This doesn't mean the "CIDR failed", it probably just means the feamale's biology was different than the protocol assumed.

Again, we have a lot of things to consider. Breed, season, age, health, etc.

- The general takeaway -

- A CIDR is a progesterone-timing tool.
- It works by exposing the female to a controlled progesterone signal, then removing that signal so the reproductive system can move forward in a tighter window.

- Next in the series:
Article 7 — Lutalyse and Prostaglandins

We're going to look at why some protocols include Lutalyse or similar products, what the corpus luteum has to do with it, and why prostaglandins remove a natural progesterone source instead of adding one.

06/02/2026

The Recipient Nobody Talks About

When folks discuss artificial insemination and, more specifically, embryo transfer, the conversation usually centers around genetics.

- The elite ram.
- The elite buck.
- The elite donor ewe or doe.
- The frozen semen.
- The embryos.
- The resulting offspring.

But there's another animal in that story that often doesn't get much attention.

The recipient ewe or doe.

I think that deserves a conversation. I posted a recent survey on our site asking people their thoughts on recips, and our top 2 responses were:

- Recips are an overlooked business opportunity for commercial producers

and

- Recips are going to become significantly more valuable over time.

I am interested in what people think and have to say about this.

Years ago, if you bought a replacement ewe or doe, you were often buying the product of an entire biological system, and this system could tell you some stuff right off the bat (assuming they were honest):

- The ewe/doe conceived.
- She carried the pregnancy.
- She delivered.
- She mothered.
- She milked.
- She raised her offspring.

A great deal of information came bundled together.

Today, technology can separate some of those pieces.

An embryo can come from one animal and be carried by another, and genetics can come from one side of the country (or world) while the pregnancy develops on the other.

This is actually pretty cool when you think about how fast we've gotten here. In fact, these technologies have created opportunities that did not exist a generation ago.

But... they also create an interesting question:

How often do we stop to think about the recipient?

Someone still has to carry the pregnancy, deliver the offspring, produce the milk, and raise the next generation.

In some ways, the technologies receive the attention while the recipient female does the work.

I'm not trying to beat anyone up; it's simply biology.

A successful embryo transfer program ultimately depends on recipient females that can reliably conceive, maintain pregnancies, deliver healthy offspring, and care for them afterward.

Those aren't trivial things, and it seems like more and more I am hearing these qualities are getting harder to reliably find. I personally haven't seen it yet, but I'm one guy in one little part of Indiana.

So here's my thoughts/question:

As embryo transfer becomes more common, what happens to recipient females?

Many people still view them as utility animals:

Necessary, but replaceable. A few producers I spoke to are telling me that individuals are expecting to pick up recips for cull prices....

Yet I am beginning to wonder if the opposite may eventually become true, and I'm wondering if it's going to happen slowly and quietly... or hit us like a brick.

What if quality recipient ewes and does become difficult to find?

What if females that consistently conceive, carry pregnancies, mother well, and milk well become increasingly valuable?

What if the industry eventually discovers that these animals were more important than we realized?

For commercial producers, I assume that will create opportunities.

Some farms may find value not only in producing offspring, but in producing dependable recipient females capable of supporting reproductive programs... some already do.

After all, elite genetics mean very little if there is no reliable female available to carry and raise the next generation.

The more I think about it, the more I wonder if recipient females are one of the least discussed pieces of the modern livestock industry.

We spend countless hours discussing genetics.

We spend countless hours discussing sires.

We spend countless hours discussing embryos.

But perhaps we should spend a little more time discussing the females that make the entire process possible.

Because at the end of the day, every embryo transfer program, every AI program, and every breeding program eventually comes back to the same thing.

A female that can successfully do her job, and that may be more valuable than many people realize.

I am interested in hearing what you think! Thanks for reading.

Tim

06/02/2026

Breeding on a Calendar - Article 5: Progesterone

Before we talk about CIDRs, we need to talk about progesterone.

I was originally going to jump right into CIDR's, but CIDR's only make sense when you understand the hormone it's trying to mimic.

This is going to be a little "busy" compared to some of our previous articles. I attempted to relay everything as simply as possible, but some of this stuff can get confusing. Just remember, this article is essential to understand if you want to know how and what CIDR's are doing.

So... here we go.

Progesterone is one of the most important hormones in reproduction, and it's also one of the easiest to oversimplify.

People often refer to estrogen as the “heat hormone” and progesterone as the “pregnancy hormone.”

That is not completely wrong, but it's not really the full story either.

Progesterone does more than support pregnancy; it changes what the reproductive system is willing to do next.

- Progesterone is the holding signal -

After a female ovulates, the o***y forms a structure called the corpus luteum.

(You will see a lot of people/literature shorten that to CL)

The CL produces progesterone.

That progesterone tells the reproductive system something important:

*Do not start another heat cycle right now*

In everyday terms, progesterone is a holding signal.

It tells the body:

- We may be pregnant.
- Don't ovulate again yet.
- Prepare the uterus.
- Keep the system quiet.
- Hold this phase until we know what happens next.

That is why progesterone matters so much.

It's NOT just a pregnancy hormone.

It is the hormone that controls the pause between ovulation and the next opportunity to cycle.

Some people think of progesterone as the gas pedal, but it's really more like the brake that keeps the system from starting over too soon.

- The corpus luteum is not just "leftover o***y tissue" -

The corpus luteum forms from the follicle after ovulation.

"Before ovulation, the follicle contains the egg and produces hormones involved in estrus behavior and reproductive readiness".

After ovulation, that same follicular structure changes...
It becomes the CL.

That's a major shift.

- The follicle helps lead to the egg being released.
- The CL helps hold the system after ovulation.
- One structure helps move the animal toward ovulation.
- The next structure tells the body to wait and see if pregnancy happened.

That's the meat and potatoes of the cycle.

- Follicle.
- Ovulation.
- Corpus luteum.
- Progesterone.
- Wait.

Then either pregnancy is maintained, or the system resets and starts moving toward the next cycle.

- Progesterone keeps the system from cycling again too soon -

IF progesterone stays high, the female usually doesn't show a normal heat.

That makes sense because the body is receiving a signal that says:

"We are in the luteal phase. Do not start over."

The brain and pituitary respond differently when progesterone is high.

- The uterus is being prepared and maintained.
- The ovaries are not being asked to immediately ovulate again.

This is why progesterone is so central to controlled breeding.

If we understand when progesterone is high, when it drops, and what the body does after that drop, we can understand a lot of what synchronization programs are trying to control.

- What happens if there is no pregnancy? -

If the female does not become pregnant, the body has to reset the cycle. The CL doesn't keep producing progesterone forever.

At the correct time, the uterus sends a signal that causes the CL to regress.

This process is called "luteolysis".

Once the CL regresses, progesterone drops.

So, why does this drop matter?

When progesterone falls, the “hold still” signal is removed, and the reproductive system can start moving toward the next heat and ovulation.

So the cycle depends on two major events:

- Progesterone rises after ovulation.
- Progesterone falls when the CL regresses.

That rise and fall creates the rhythm.

Without that rhythm, the system becomes difficult to time.

- Progesterone does not make heat happen -

This is where people can get confused.

*Progesterone itself isn't the hormone that makes the female stand in heat*

As mentioned above, high progesterone usually suppresses visible heat.

The important moment is often the WITHDRAWAL of progesterone.

When progesterone drops, the reproductive system can move toward the next follicular phase.

- Follicles can continue developing.
- Estrogen can rise.
- Behavioral heat can become more obvious.
- Ovulation can follow.

That's why a drop in progesterone matters so much.

The body is not responding only to the presence of progesterone. It's also responding to the REMOVAL of progesterone.

*This concept is the foundation for understanding CIDRs.*

- Why this matters for CIDRs -

A CIDR is basically a controlled progesterone signal.

It releases progesterone or a progesterone-like signal into the female’s system.

The goal is to temporarily place the reproductive system under progesterone influence.

In plain language, a CIDR is trying to tell the system:

"Hold still for now."

Then, when the CIDR is removed, that artificial progesterone signal drops, and that drop can help the group move more predictably toward estrus and ovulation.

*This is why CIDRs are used in synchronization.*

They are tools built around progesterone biology.

- Why this matters for Lutalyse -

Lutalyse and similar prostaglandin products make more sense here too.

- The natural CL produces progesterone.
- If a female already has a functional CL, she already has a natural source of progesterone.
- A CIDR may add a controlled progesterone signal, but the animal’s own CL may still be producing progesterone too.

That's one reason you may see some protocols include a prostaglandin.

- The prostaglandin is used to cause regression of a responsive CL.
- When the CL regresses, natural progesterone drops.

So in simple terms:

- CIDRs add a temporary progesterone signal.
- Lutalyse helps remove a natural progesterone source from the CL.

These are different jobs, but both are connected to progesterone.

That's why understanding the CL matters before we start talking about protocols.

- Timing matters because the CL changes over time -

The CL is not equally responsive every moment after ovulation.

- A very young CL may not respond the same way as a more mature CL.
- A female that has not ovulated may not have a CL to regress.
- A pregnant female may be depending on progesterone to maintain pregnancy.

That is why prostaglandins are powerful tools, and why timing matters.

- If there is a functional CL, prostaglandin can help remove that progesterone source.
- If there is no responsive CL, the result may be different.

Side note: If the animal is pregnant, interfering with progesterone support can be a SERIOUS problem.

- Progesterone is why protocols have a pause-and-release pattern -

A lot of synchronization programs are built around the same basic logic:

- Hold the system under progesterone influence.
- Remove the progesterone signal.
- Clear any natural CL if needed.
- Allow the reproductive system to move toward estrus and ovulation in a tighter window.

That's the pattern.

- Pause.
- Release.
- Synchronize the response.

This is why progesterone sits at the center of controlled breeding, because controlling progesterone helps control timing.

- The practical stuff in a nutshell -

- Progesterone is the reproductive system’s holding signal.
- It rises after ovulation because the CL produces it.
- It helps prepare and maintain the uterus.
- It keeps the system from immediately starting another heat cycle.
- When the CL regresses and progesterone falls, the system can move toward the next opportunity to breed.

This rise and fall is what the rhythm-controlled breeding programs are trying to manage.

Once we understand progesterone, CIDRs aren't as confusing, Lutalyse stops looking like “just another shot", and synchronization starts looking less like a list of chores and more like an attempt to control the timing of a real reproductive cycle.

- Next in the series -
Article 6 - CIDRs

We will look at what a CIDR actually does, why it mimics a progesterone signal, why removal matters, and why CIDRs control timing without creating fertility from nothing.

Linessa Farms, LLC

06/19/2026

06/17/2026

06/15/2026

06/09/2026

06/04/2026

06/02/2026

06/02/2026

Address

Opening Hours

Telephone

Website

Alerts

Contact The Business

Shortcuts

Share

Category