GnRH question

[red]

I aked this question in another thread but think it got lost in the mix.
Since GnRH causes the egg to be released quicker, will this affect the sex of the calf? I guess I sort of following the thoughts of timing of AI'ing influencing the sex so wondered if this had a factor.
This is a hubby question actually.

Red

 

[shortyjock89]

I always think of GnRH as kind of a "re-set" button, rather than "fast-forward"..is that right? DL?  So if you go by my reasoning, then no, GnRH will not affect the sex of the calf.  I could be wrong, but I gave it a shot lol.

 

[Cowboy]

Red, I agree for the most part with the above, the shotof Gnrh  - in itself - will not affect the sex of the calf from the standpoint of producing a female or male egg -- as that is dictated by the sperm cells themselves.

On the flip side of the coin, you "MAY" be able to see a slight difference over time and many many breedings by the fact that male sperm cells do swim faster, and die sooner. By asking her to dump the egg sooner (All the time hoping it will be ready for fertilization) it would at least in theory, give the male cells a better chance of getting there first and not having to wait for ovulation to occur. This is when everything works just as it is supposed to -- and how many times does that happen? Not enough I will add.

Hope that answers your thought chain, hubby will most likely smile and say "Smart A**", just tell him in reality no I am most certainly NOT - hehehehe!

See ya -- Terry

 

[shortdawg]

So when would be the optimum time to breed to maximize your chances for a heifer ? Using your breeding program, how many hours after the onset of heat would you breed if you wanted a heifer ?

 

[DL]

I always think of GnRH as kind of a "re-set" button, rather than "fast-forward"..is that right? DL?  So if you go by my reasoning, then no, GnRH will not affect the sex of the calf.  I could be wrong, but I gave it a shot lol.

SJ89 - that is sort of like I thought of it too
Basically GNRH (aka gonadotropin releasing hormone) is a mimic of a hypothalamic hormone that causes release of pituitary hormones LH (leutinizing hormone) and FSH (follicle stimulating hormone)
so it goes like this GNRH ---> surge of LH and FSH --->ovulation of mature follicle (24 to 30 hours later - times based on "natural hormone")
so although it could have an effect on the sex of the calf I believe it would be easier if you want heifers to breed with the cow facing Lake Louise and if you want bulls have them face St Croix