# Who determines size of offspring, cow or bull?



## cjb (May 2, 2006)

My jersey cow is quite large. I was actually disappointed when I went to pick her up 3 years ago because she was just so big and I expected a Jersey to be small-ish. 

I had her bred last time around to a small bull. He's not a mini but he was quite small. The resulting calf will be one year next month and she seems TINY to me. I plan to breed her at 15 months but man, she is pretty dang small. 

Do they take a long time to mature in size or do I have the little heifer I wanted because I used a small sire?


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## ksfarmer (Apr 28, 2007)

The genetics of both parents will contribute to calf size. The bull may have more effect than the cow tho.


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## HOTW (Jul 3, 2007)

Genetics are part of it but I do know my DH cousin used to AI heifers to a bull that was known to throw small babies so they had an easier time of it.Then the next year they'd go for production. These were Holsteins and he preferred to keep first time calves under 75 lbs. Some of his ladies were huge there was a family group that we think they averaged about 1600 lbs! Gentle as could be though


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## deineria (Aug 22, 2009)

I am not sure, but I also have a smaller Jersey heifer, I've been told. I plan to use sexed semen, so that is know for small calves, so I will breed her at 15 months either way. I was told by the nuns we bought her from that breeding her at 500 lbs was ok, and I'd say she is 375 or more now, so I know she will be 500 by one year, so I have no issues breeding her at 15 months. I posted photos on your other post. I hope she is under 800 when full grown, actually.


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## Karin L (Oct 5, 2006)

It is thought that, primarily, calf-size is more attributed to the sire's side than the dam. I've read a lot about this, from when cattlemen put a Simmental bull on their cows one year and they got huge calves as a result, since Simmental is notorious for throwing big calves; but when they put an Angus bull on their cows, the calves were remarkably smaller (not to mention the smaller calves were easier on the cows). However one also has to remember that half the genetics come from the dam as well. But I do believe that the bull is the one at fault for giving you such a small calf from your Jersey cow, CJB. A large Jersey cow like her would obviously have the genetics for throwing larger calves, but a small bull with genetics for throwing small calves would override those large-calf genetics and produce the kind of calf you got.


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## linn (Jul 19, 2005)

I would agree that using a bull known for small offspring would contribute to a smaller calf. Yes, the cow does contribute to the gene pool, but as one member stated, I believe that the bull will in most cases outweigh the cow's contribution.


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## cjb (May 2, 2006)

I'm actually quite happy to have a smaller heifer. The Mom is quite large but extremely gentle but I think a smallish Jersey cow will be nicer to have.

Thanks for all the information.


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## cowkeeper (Feb 17, 2007)

Would like to know the name of that sire. I have a 49 inch Jersey and would like to breed her for a smaller calf. TIA .ck


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## cjb (May 2, 2006)

I will look it up for you.


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## francismilker (Jan 12, 2006)

Always thought it was pretty much the bull that played the major part in determining calf size. However, yesterday about noon one of my mini jerseys had a heifer calf out of a bull that is for the most part called "a black bull". He is 1/2 maine anjou, 1/4 brangus, 1/4 angus. (just wanted to put a beef bull on the girls this crop because I've got enough milkers for the time being.) My beefer buddy down the road was going to knock him in the head because he was blind in one eye so I raised him. I didn't know what kind of birthweight he might throw but knew he would be breeding cows that had birthed calves before so I wasn't too worried about it. 

Anyway, today I noticed the cow in labor so I figured I'd check her in an hour or so in case she needed some help. Thirty minutes later I came outside to a jack-rabbit sized heifer calf. I weighed it to find out it tips the scales at just over 34lbs. What a whopper! 

I've got all the rest of my herd bred to the yearling black bull so I'll find out soon enough an average birthweight of his calves.


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## cjb (May 2, 2006)

Oh that's cool Francis. I'll be anxious to hear. Also, please post pictures of the jackrabbit.


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## cowkeeper (Feb 17, 2007)

I bought some Sunset Canyon Dice he is right up there for components with a minus 9 for stature.ck


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