Polled or not polled?

[HOSS]

OK......scenario question for all of you genetics folks. Let's say a man has a polled bull who's grand mammy had horns and his great grand mammy had horns but the rest of his lineage out for several generations on both his sire and dams side were polled. If this bull is bred to polled commercial cows (of course polled / horned genes are not known on these cows) what are the chances that a horned calf will pop up?

 

[randiliana]

Well, his dam would have been Pp. So if his sire was pp, there is a 50% chance that he is homo polled (pp) and a 50% chance that he is hetero polled (Pp). So you can take it from there. If he is homo polled(pp), 100% of his calves will be polled, regardless of the cow's makeup. If he is hetero polled(Pp), it will totally depend on the cows. If they are homo polled, then the calves will all be homo polled. If the cows are Pp, 25% of the calves will be horned (PP), 50% of the calves will be hetero polled (Pp) and a 25% of the calves will be homo polled.

It works like this
Pp x pp = Pp, Pp, pp and pp
Pp x Pp = PP, Pp, Pp and pp

 

[msscamp]

OK......scenario question for all of you genetics folks. Let's say a man has a polled bull who's grand mammy had horns and his great grand mammy had horns but the rest of his lineage out for several generations on both his sire and dams side were polled. If this bull is bred to polled commercial cows (of course polled / horned genes are not known on these cows) what are the chances that a horned calf will pop up?

50% - it takes two parents with a horned gene to produce a horned calf, the gene is either there or it isn't.

 

[dun]

If both cows and bulls are heterozygous polled, one horned and one polled gene, the odds of a horned calf are 1 in 4. If either the cow or the bull is homozygous polled, all the calves will be polled.

 

[KNERSIE]

Well, his dam would have been Pp. So if his sire was pp, there is a 50% chance that he is homo polled (pp) and a 50% chance that he is hetero polled (Pp). So you can take it from there. If he is homo polled(pp), 100% of his calves will be polled, regardless of the cow's makeup. If he is hetero polled(Pp), it will totally depend on the cows. If they are homo polled, then the calves will all be homo polled. If the cows are Pp, 25% of the calves will be horned (PP), 50% of the calves will be hetero polled (Pp) and a 25% of the calves will be homo polled.

It works like this
Pp x pp = Pp, Pp, pp and pp
Pp x Pp = PP, Pp, Pp and pp

Randi, I am sure it was just a brain fart, but I'll still point it out.

The capital letter indicates the dominance, so polled will be P.
Homozygous polled PP
Heterozygous polled Pp
Horned pp

 

[randiliana]

Well, his dam would have been Pp. So if his sire was pp, there is a 50% chance that he is homo polled (pp) and a 50% chance that he is hetero polled (Pp). So you can take it from there. If he is homo polled(pp), 100% of his calves will be polled, regardless of the cow's makeup. If he is hetero polled(Pp), it will totally depend on the cows. If they are homo polled, then the calves will all be homo polled. If the cows are Pp, 25% of the calves will be horned (PP), 50% of the calves will be hetero polled (Pp) and a 25% of the calves will be homo polled.

It works like this
Pp x pp = Pp, Pp, pp and pp
Pp x Pp = PP, Pp, Pp and pp

Randi, I am sure it was just a brain fart, but I'll still point it out.

The capital letter indicates the dominance, so polled will be P.
Homozygous polled PP
Heterozygous polled Pp
Horned pp

hahaha, you're right Knersie. Just a mixup on my part, and I should know better Thanks for pointing that mistake out.

 

[spoon]

Well, his dam would have been Pp. So if his sire was pp, there is a 50% chance that he is homo polled (pp) and a 50% chance that he is hetero polled (Pp). So you can take it from there. If he is homo polled(pp), 100% of his calves will be polled, regardless of the cow's makeup. If he is hetero polled(Pp), it will totally depend on the cows. If they are homo polled, then the calves will all be homo polled. If the cows are Pp, 25% of the calves will be horned (PP), 50% of the calves will be hetero polled (Pp) and a 25% of the calves will be homo polled.

It works like this
Pp x pp = Pp, Pp, pp and pp
Pp x Pp = PP, Pp, Pp and pp

That looks a lot like the stuff I didn't understand in high school algebra class years ago. :help:

 

[3waycross]

He[[ I still don't understand it. It gave me a headache then and it still does.

 

[ANAZAZI]

Hor5n status for great grand dam horned; bred to polled bull.
grand dam, heterozygous polled bred to polled bull that were homozygous; than 50 per cent chance of being either hetero or homo polled; or bred to heterozygous bull 67 per cent chance of being hetero polled and 33 per cent chance of being homo polled.
Dam polled homo or hetero bred to polled bull homo or hetero; her son is either one or the other, but the question is how likely?
The possibilities becomes becomes multitudous, however if there were no offsprig horned for three generations, it is a little more likey that the bull is homo polled, but the only way to find out is to breed him to ten or so horned cows.

 

[Keren]

Well, his dam would have been Pp. So if his sire was pp, there is a 50% chance that he is homo polled (pp) and a 50% chance that he is hetero polled (Pp). So you can take it from there. If he is homo polled(pp), 100% of his calves will be polled, regardless of the cow's makeup. If he is hetero polled(Pp), it will totally depend on the cows. If they are homo polled, then the calves will all be homo polled. If the cows are Pp, 25% of the calves will be horned (PP), 50% of the calves will be hetero polled (Pp) and a 25% of the calves will be homo polled.

It works like this
Pp x pp = Pp, Pp, pp and pp
Pp x Pp = PP, Pp, Pp and pp

Randi, I am sure it was just a brain fart, but I'll still point it out.

The capital letter indicates the dominance, so polled will be P.
Homozygous polled PP
Heterozygous polled Pp
Horned pp

hahaha, you're right Knersie. Just a mixup on my part, and I should know better Thanks for pointing that mistake out.

WHOAH!

All this time I thought polled was a recessive

 

[randiliana]

WHOAH!

All this time I thought polled was a recessive

No, polled is dominant. It only takes 1 polled gene to make the animal polled. It is why you can take a homo polled breed (say Angus) and use him on a horned breed (say Hereford) resulting in the entire calf crop being polled.