Timing your breeding to get a heifer calf

[topstock]

Has anyone heard the theory if you breed early in the heat cycle you'll increase your chances of a heifer and later in the cycle will most likely produce a bull?

 

[Travlr]

Has anyone heard the theory if you breed early in the heat cycle you'll increase your chances of a heifer and later in the cycle will most likely produce a bull?

Male sperm is faster and female is more long lasting...

That means that if you breed early enough in estrus the male sperm will die or lose motility before reaching the egg. Good AI techs insert straws in the horn of the uterus that is ovulating for male calves and in the opposite horn for females.

There are some other things you can do to influence gender as well. The trick is to influence the medium the sperm has to swim in by making the environment more or less acidic. It takes about two months to see any real difference. Feeding high protein and high mineral tends to favor male sperm motility and more carbs tends to favor female sperm success. Body temperature has something to do with it as well. Also if the cow is gaining weight, which favors female sperm, or just maintaining weight, favoring male.

And the two genders have different odds of success. One is just over 70% and the other is around 67%.

There may be more current science available today.

 

[topstock]

Thank you for all that info. For years my husband and I have gone by that theory ( and it works!) but my 19 year old insists it's the opposite. He can have all the bulls lol.

 

[Jeanne - Simme Valley]

@Travlr is absolutely correct about male sperm being slender and fast - female fat & slow. Early breeding produces more females.
I have been breeding Simmental AI for 50+ years. The problem with breeding early (which I do in the first week or two of my breeding season), you may not get them pregnant. Male & slow females may arrive and the egg still hasn't been released. Later breeding is a higher pregnancy rate.