horns

[scottlive]

I exposed my horned cattle to a polled bull and was wondering if the calves will have horns or not?

 

[1982vett]

If he is Homozygous polled, all offspring will be polled. If he carries the horned gene then up to 1/2 of his offspring could be horned.

http://www.purebreddextercattle.org/Articles/Polled.htm

 

[scottlive]

The bull is a polled black simmental the cows are 1 short legged 1 long long dexter

 

[1982vett]

Doesn't matter the breed of cattle. Polled genetics are the same across breeds.

P = Polled p= Horned

PPxPP= Polled
PPxPp= Polled
PpxPp= 3/4 Polled 1/4 Horned
Ppxpp= 1/2 Polled 1/2 Horned

 

[scottlive]

Thanks for the help. The calves are sure nice looking. Both Cows came through with flying colors.

 

[1982vett]

Post some pictures if you can.

 

[bigbull338]

the calves should be polled.but some could be horned as well.alot depends on the cows an bull.

 

[Santas and Duhram Reds]

Using Mendel's simple formula for figuring dominance with polled/horned genes you can figure that on average a certain percentage of your calf population will be horned/polled but you must also realize that each calf has the same chance of being either polled or horned. SO, in other words it is possible that ALL your calves be either horned or polled. Not likely but possible.

 

[dun]

There is a magic number of breedings, don;t recall what it is, that will give you the probability of th bull being homozygous. Works something like, if he's bred to 10 cows and all are polled the probability of him being homozygous is 75%, each 10 matings or so will polled calves out of horned cows increases the probability 5%. Those aren't the exact numbers but are close I think. If he throws one horned calf, no matter how matings to horned cows are made, he's heterozygous polled. If he's heterozygous, bred to horned cows the the chances of a calf being horned are 50:50, basicly the same as the chances of a heifer or bull being born from any mating. The difference is that polled/horned is controlled by a gene pair, gender is controlled by other factors but is still roughly 50:50.

 

[3waycross]

There is a magic number of breedings, don;t recall what it is, that will give you the probability of th bull being homozygous. Works something like, if he's bred to 10 cows and all are polled the probability of him being homozygous is 75%, each 10 matings or so will polled calves out of horned cows increases the probability 5%. Those aren't the exact numbers but are close I think. If he throws one horned calf, no matter how matings to horned cows are made, he's heterozygous polled. If he's heterozygous, bred to horned cows the the chances of a calf being horned are 50:50, basicly the same as the chances of a heifer or bull being born from any mating. The difference is that polled/horned is controlled by a gene pair, gender is controlled by other factors but is still roughly 50:50.

How does that work then for a scurred bull. what are the percentages. For example what shoud he do on a mixed herd some polled and some horned.

 

[dun]

How does that work then for a scurred bull. what are the percentages. For example what shoud he do on a mixed herd some polled and some horned.

Don;t know about scurs. They're supposedly a sex linked deal and since the scur genes and horned genes are 2 different sets the breeding deal with probabilitys probably wouldn;t work.
One thing that frquently confuses people is seing scurs on a polled animal. You won;t see scurs on a horned animal so when they see them on a polled one they think they are vestual horns.

 

[RVF]

There is a magic number of breedings, don;t recall what it is, that will give you the probability of th bull being homozygous. Works something like, if he's bred to 10 cows and all are polled the probability of him being homozygous is 75%, each 10 matings or so will polled calves out of horned cows increases the probability 5%.

If I did the math correct, there is a 1% chance that a heterozygous polled bull will give all polled calves when mated to horned cows.

The difference is that polled/horned is controlled by a gene pair, gender is controlled by other factors but is still roughly 50:50.

Dun I am not sure what you mean by this. gender is contolled by a single gene pair, just like polled/horn and every cow has a 50% change of a bull calf and a 50% chance of a heifer calf. I assume by other factors, you are talking about things like breeding the cow early or late in her heat period to try and influence the sex ratio, some bulls/cows ability to produce a high proportion of bulls or heifers etc. which would normally be attributed to non-genetic effects.