How young can heifers come into heat?

[bigbull338]

yes an no on the stunting calving them young.yes it would stunt them if they wasnt tended to.calving under 20 months old takes alot out of them.b/c they have to maintain themselves.plus feed the calf.if a heifer weans off a big calf.an gets pulled down in the 1st 90days of calving.she wont breed back on time.may even take 5 months to get her bred back.scott

 

[ALACOWMAN]

When the calf is in the uterus it constantly taking nutriants from the mother.while she herself is trying to grow.then when she calves along with the stress of calving she has a little leach pulling the life out of her. so there no dought about the animal being stunted. you could off set it to some extent by feeding.but that would be exspensive.thats why i would pull the calf off early so she can play catchup.it cheaper to sell the baby and the heifer could go about her real business of becoming a cow.

 

[Dana Kopp]

I agree with both Big Bull338 & Alacowman - if you were to have a yearling calve out and then kick her out on a dry sparse pasture where she had to really travel for water and feed or compete with older cows for feed she most likely will be stunted. This could even effect her milk production and thus her calf growth depending on how her body "divides" up the nutrients.
We have supplemented those girls with some calf creep or steer gain feed for a couple weeks and made sure that they had good hay and then good grass with the rest of the herd. Yes, for the first and second years after they had the calf they were slightly shorter and bonier than the others but we pulled the first calf off a little early and by the time calf #2 was weaned you couldn't tell any difference anywhere.
As for lack of milk production, we didn't have a problem though the first one took a couple days for good milk to really get rolling. She had milk (colostrum actually) but it just wasn't as much as the older cows. The others didn't have any problems.

There are a lot of variables in calving in general much less at such a young age. Personally, I wouldn't try to squeeze an extra calf in - the loss of a heifer or calf plus the work and worry would eliminate the money you might make.