Estrous synchronization (4)

Estrous synchronization

…. allows the controlling of estrus or exactly when ovulation occurs which allows for better management of herds/flocks in order to have both a confined breading and calving/lambing period 

cattle

The work in estrous synchronization was mainly done in ….. because they have a 9 month gestation

fourth cycle

In synchronization, we add a …. that allows more animals to be able to become pregnant within the breeding season 

drugs

There are …. that mimic the natural hormones in the body in order to better control the cycle 

Estrogen

…. in the US is banned

calendar or schedule 

Estrous synchronization is making the animal’s body meet our ….

labor

Estrous synchronization can better control …. 

exogenous hormones

We need to give the …. to control the cycle is given at the right time 

uniformed

The more …. they are, the higher the valve 

artificial insemination

When estrous synchronization occurs, there’s an opportunity to use ….. (not required)

Progesterone

…. is what truly controls the reproductive system 

blocks

When progesterone is high, it …. the dominant follicles from ovulating which would cause them to die

CIDR

When we use a …, progesterone concentrations would remain high and is going to continue block ovulation 

corpus luteum 

When manipulating the estrous cycle; we are targeting the ….

Prostaglandin

…. targets the CL and cause it to regress 

Progestins

…. mimics progesterone 

prostaglandin (PGF2a)

Once we give the shot of …., we expect to see the females show estrus

metaestrus

If we give a single injection of prostaglandin (PGF2a), 60-60% will respond because the follicular phase is 25-33% and the luteal phase is 66-75%. Within the luteal phase, the …. is going to be unresponsive 

2 injections 

If we want 100%, we can use the combination of ….

Analogs

Pharmaceutical products that is very similar in nature as cause the same response 

cycling

When using PGF2a and analogs, the animal must be …. cus they only target CLs and if there’s no CLs when the animal is in estrus, it won’t work 

mammalian

It effects all …. species 

Synchronization with PGF2a

We inject the first injection of PGF2a and we expect the regression of the CL and they would express estrous.

heat check

So we … (if we are artificially inseminating, then we do a heat check for 2-7 days to see who responds) we expect 60-65% to respond

no breeding

We would then wait (in this case 12-14 days) and give the second injection. Because we are planning to give the 2nd injection, there would be …. after the first injection.

lose

This is because PGF2a would kill the CL, so if we inseminate those animals after the 1st injecting and they happen to become pregnant, and we give them the 2nd injection then they would …. the pregnancy so we wait

decrease

PGF2a will target the CL and the result is to …. progesterone 

block ovulation

Progesterone goes into the blood, go up into the hypothalamus and block the surge center. So the ultimate plan is to …., we want this because we want to block the animal from ovulation in her own schedule so that she’ll ovulate on our schedule 

PGF2a

Adding progesterone and removing it doesn’t regress the CL, you need …. 

control

CIDRs are easy to …. 

everyday

If we are using an injectable, we need to give it an appropriate time …..

feed source

If we are using a …., we need to make sure it’s fed everyday around summer time 

feeding

MGA is easy to use if ….

bossy

MGA is harder to balance what each cow gets because some cows are …. and eat more than others 

7 days

CIDR is/can be used to block ovulation. One of the most common methods is to leave the CIDR in cows for … and the day we remove it, we use PGF2a in order to get her to respond (remove all progesterone) 

prevent

We use progesterone supplementation to … a pregnancy 

removes all the follicles

In synchronization of ovulation, on day 0. We give the first injection of GnRH which basically …. that would respond to the LH surge, meaning that we reset the follicular wave 

new follicles

On day 7 (after we give time for the follicles to grow), (if a CL forms) we give PGF2a which would cause regression of the CL. This would decrease progesterone and ideally, … would be growing 

30-48 hours

We would the wait …. (depends on if it’s a heifer or a cow) then give another shot of GnRH which would induce ovulation 

12 hours

From the time the LH surge happens to the time the oocyte is actually in the oviduct is about …

sperm cell

So we give that shot of GnRH in the morning and then breed the females in the evening in order to optimize the time to have the … meet the oocyte  

Estrous synchronization

The goal of …. is to control estrus (heat) and ovulation in females so that breeding can be completed in a short period of time

Potential advantages of estrous synchronization

Can shorten breeding season - Shortened time to breeding - Utilizes labor more efficiently - No heat checking needed - Reduced days to first service - Groups timing of parturition (Uniform crop of offspring)

Potential disadvantages of estrous synchronization

Increased labor costs - Requires skilled labor and periods of intensive management (multiple injections) - Requires adequate facilities (Less time spent observing animals (can miss detecting non-cyclers in herd)) - Higher input costs (Need to examine economics first - Costs balanced by increased returns)

Prostaglandin and Progestins

Manipulation of the cycle

Prostaglandin

Lutalyse, Estrumate, Prosolvin - Bovilene, etc

Progestins

Progesterone - MGA (Melengesterol acetate) - Norgestomet - PRID (Progesterone Releasing Intravaginal Device) - CIDR (Controlled Internal Drug Release)

Prostaglandin (PGF2a)

Has no effect on days 0-5

Factors to consider for prostaglandin F2a and analogs

Animals must be cycling - Easy to use - Cost ($1-3 per dose) - Can be combined with GnRH for times AI

Progesterone

Suppress estrus by reduces GnRH pulses thus preventing the pre-ovulatory LH surge

CL

Progesterone will not regress the …

Administration of progesterone for livestock species

Injection (time consuming) - Feed (mix in the ration) - Implant (Place in ear) - Pessary or control internal drug release (CIDR) (place in vagina)

Progesterone

Can be used with proper delivery method (CIDR)

MGA

Cheapest - Oral administration (ease of use, less control of therapeutic levels, longer treatment time required)

Norgestomet

No longer on the market

PRID and CIDR

Easy to use - Multiple inserts can be used to alter therapeutic levels - Retention rates about 95% - Storage of used devices

CIDR recommendation

Implant for 7 days - Inject PGF on day 6 or 7 - Heat check and breed after heat for next 3-4 days after CIDR removal