Calf color from cleanup bull.

[birdog]

I have a neighbor who AIs his Red Brangus cows with Red Brangus semen and uses a Black Brangus bull for cleanup. He says it helps him identify the calves from the AIs. My question is, If the Black Brangus bull he is using carries the red gene which I think it could because I know the breeder where he purchased him, can he really identify the calves from the color. My understanding of genetics he would have a 25% chance of red calves from this bull that he would assume came from his AI program. Not that it matters, he is not registering the calves just commercial operation. :?:

 

[dun]

You're right. If the black bull is a red carrier there is a possibility of a red calf from him. But with the 3:1 odds in the favor of black, theose red calves would be just incidental statistics. A friend of mine used blk Angus bull on his heifers for 3 months then moved them over to a Polled Hereford bull. That way he could tell if the Angus had a problem. This was a dairy so the calving age as heifers didn't really matter all that much to him since he sold most of them as springers anyway.

dun

 

[txag]

if he's using a black bull which carries the red gene on red cows, 50% of the calves should come out red, not 25%.

if a heterozygous black bull was being bred to heterozygous black cows, then you would expect 25% of the calves to be red.

 

[birdog]

txag;

Your right thanks for the correction.