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#39145 - 10/14/08 09:36 AM Re: Wyandottes
Hen-Gen Offline
Ruler of the Roost

Registered: 10/01/05
Posts: 1141
Loc: Island of Fetlar, Shetland
Thanks for your input, guys. So it seems that the impared sperm motility and viability of pure rosecombed cockerels is of negligible importance in most practical situations.
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#39146 - 10/14/08 02:43 PM Re: Wyandottes
Choc Offline
Coop Keeper

Registered: 03/10/06
Posts: 489
Loc: England
I would agree with that Hen-Gen. I have bred thousands of wyandottes over the years and there is nothing to suggest to me the link between rose combed birds and reduced sperm viability.
However, that is just my experience.

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#39147 - 10/14/08 04:00 PM Re: Wyandottes
IPF Offline
Coop Keeper

Registered: 04/08/08
Posts: 466
Loc: Canada
The fact that homozygous (RR) males don't appear to have reduced fertility does not prove that there is not differential sperm motility/viability between R and r sperm.

If there are no r sperm to compete with, an R sperm will always "win". Only if the rooster is heterozygous, will the discrepancy (if it indeed exists) appear.

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#39148 - 10/14/08 04:24 PM Re: Wyandottes
Blackdotte Offline
Ruler of the Roost

Registered: 10/02/04
Posts: 913
Loc: Australia
If you have heterozygous R/r+ birds and,as most exhibition breeders do, use very high cock:hen breeding ratios you may never see a single comb.
But if you go to commercial cock: hen breeding ratios of 1 cock to at least 25 hens then the single comb will become more apparent. Free ranging will exacerbate the situation.
The r+ single comb gene must however be present.
Many breeders have,by test matings, got rid of the r+ gene, and that maybe why single combs are not seen in NZ, or in Choc & Mau's birds.

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#39149 - 10/15/08 05:19 AM Re: Wyandottes
Sigi Offline
Ruler of the Roost

Registered: 11/23/06
Posts: 1150
Loc: Holland
That was just what I was thinking. When you breed a flock for enough years and 1:1 or 1:2 ratio, the r+ should disappear.

Here are breeders of the Wyandotte club who do have single comb birds and yes they have their birds outside in large pens.
I guess when the cock has a special hen, he doesn't jump enough on the others, even if there are only 3 or 2 hens.

Another question on single combs in rose.
The single comb is there when the R fraction in the sperm dies and only r+ is still active. Means the cock is heterozygous.
So the R not changing into r+ after a while? R just stops to exist?

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#39150 - 10/15/08 06:09 PM Re: Wyandottes
Blackdotte Offline
Ruler of the Roost

Registered: 10/02/04
Posts: 913
Loc: Australia
Quote:
When you breed a flock for enough years and 1:1 or 1:2 ratio, the r+ should disappear.
No, it could still be still be there, but the frequency will be reduced. Only sure way to get rid of it is to test mate.

Quote:
So the R not changing into r+ after a while?
Correct R does not change into r+.

Quote:
R just stops to exist?
The R allele dies after about 3 days; the r+ allele lives on for up to around 21 days.

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#39151 - 10/16/08 11:27 AM Re: Wyandottes
Sigi Offline
Ruler of the Roost

Registered: 11/23/06
Posts: 1150
Loc: Holland
That means that if there is no r+ in a flock anymore, and the cock doesn't mate enough, there's a high percentage of empty eggs?

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