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#115340 - 01/04/16 07:10 AM Re: Long egg? [Re: J. Henderson]
Robbie Offline
Flock Leader

Registered: 01/19/15
Posts: 258
Loc: Ontario Canada
I've been unable to find a reference (One that I can read, no access to the ones I have found) that describes how long egg shape is inherited. I have Buckeyes that lay very long eggs....... I just got one egg that has an egg index of 64.6 (!). I have Cornish that lay very round eggs. Would a cross between those two breeds likely produce hens that lay "properly" shaped eggs, or would I get a mix of crossbred hens, some that lay long eggs, others that lay round eggs?

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#115348 - 01/06/16 07:02 AM Re: Long egg? [Re: Robbie]
Robbie Offline
Flock Leader

Registered: 01/19/15
Posts: 258
Loc: Ontario Canada
Nobody knows if I cross a long- egg laying hen with a rooster descended from a hen laying a properly shaped egg, if the F1 pullets will either lay long, or properly shaped eggs, or intermediate shaped eggs? Is long egg shape a recessive, dominant, codominant, or incompletely dominant trait?
I'd rather not have to find this out for myself! Anyone, please?

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#115349 - 01/06/16 11:58 AM Re: Long egg? [Re: Robbie]
CJR Online   content
Coop Master

Registered: 07/16/02
Posts: 8489
Loc: Montana
Over many years of raising bantams, with selection for "best" offspring for breeding, the eggs are are part of that selection. My experience: There is almost NO variation in the egg shape of EACH hen--it is their own design, but size may have slight variation at times (early and later lay of a clutch). In a pen with 4 hens, in a short time, one can identify the egg of each hen. Sometimes these hens are sisters, sometimes daughters of one of the hens. Eggs, exept rarely, have only slight differences. If they have the same shape and size, there will be a variation in shell texture or slight variation in tint of shell, even if same breed and variety. These keep the eggs of each hen easily identified and labeled and dated when collected from the same nest. I select the eggs for hatching by parentage and rarely hatch eggs that are not a good shape, unless I have a great type hen that lays eggs of "long" or very round shape, but with a male that I wish to keep. I work with small numbers of birds, compared to those who raise hundreds. And I keep records (for years!). Have kept up to 12 pens of trios or foursomes, and prefered to hen hatch, marking chicks at hatch and often giving one hen, chicks from several pens set, to hatch at same time. Flock hatching would never be my method of breeding. So looking back, I would not select on egg shape, as an inherited trait. The Very few chicks that I have hatched from good hens that layed poorer shaped eggs, if grown into good type for their breed/variety, joined the breeding flock with no notice of eggs produced by them, being anything like the odd shape they hatched from. Not the numbers to be conclusive, but maybe useful?

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#115350 - 01/06/16 01:15 PM Re: Long egg? [Re: CJR]
Redcap Offline
Ruler of the Roost

Registered: 08/14/06
Posts: 954
Loc: Germany
I am sure, You have found these studies as well.
http://ps.oxfordjournals.org/content/22/1/61.abstract
Quote:
SUMMARY

Egg shape is unusually uniform for eggs laid by an individual bird. The mean co-efficient of variability was 3.33 percent. The strain of (327 unselected) Barred Plymouth Rocks studied did not show a significant seasonal fluctuation in egg shape index. The first egg in the clutch, for clutches up to 10 eggs, is slightly longer and narrower than eggs laid later in the same clutch. The shape index of eggs laid later in the clutch does not appear to differ significantly from the index of the second egg of the clutch. The first egg laid after a pause of seven or more days is significantly longer and narrower than the last egg laid prior to the pause. Normal egg shape is attained again by the time the fifth egg is laid. Double-yolked eggs have a significantly lower index than normal eggs laid by the same bird. These data show that measurements on all double-yolked eggs and eggs laid immediately following a pause should be omitted in egg shape inheritance studies. Egg size did not influence egg shape in this strain of Barred Plymouth Rocks when data on double-yolked eggs and dwarf eggs were omitted.
Egg shape is governed by hereditary characters. Reciprocal crosses of distinct lines for round and long egg shape show an intermediate egg shape mean in the F1 progeny. The F2 and back-cross data offer some evidence of a single gene hypothesis but are not adequate to definitely establish the genetic basis of inheritance.

http://www.jstor.org/stable/3001710?seq=1#page_scan_tab_contents
Quote:
SUMMARY

1. An analysis of variance and covariance was carried out for egg shape
(100 x width/length) using the first and second position eggs of two clutches from
each of 498 pullets in the U. C. production-bred flock, 134 pullets from
eight inbred lines, and 154 pullets from crosses between these inbred
lines.
2. No interactions between clutch positions and other sources of
variance (sires, dams, pullets) were found.
3. The shape index for both clutch positions was greater in the second
clutch than in the first clutch measured indicating that the shape index
was increasing during the period in which measurements were taken
(March and April). The difference was significant.
4. The shape index of the second position was significantly higher
than the index of the first position. If the distinction between positions
is disregarded, the consequent reduction in heritability is negligible.
5. Heritability estimates ranged from .11 on the basis of a single
second position egg to .19 on the basis of the mean of two first position
eggs. Heritability for the index of the first position was higher than that
of the second position.
6. The estimate of the theoretical maximum heritability (an infinite
number of eggs measured per individual) was .25 and .16 for the first
and second positions respectively.
7. Evidence of sex linkage was obtained from the analysis of the
production-bred flock and the crosses between inbred lines.
8. Under the above conditions, improvement of a character (expressed
only in females) would be made most efficiently by the use of
combined individual and sister (for sex-linked genes, full and half sister
records are of equal value) selection of pullets and by the use of sister
and progeny testing in the selection of males. In the case of sex linkage,
daughters' records are of no value in the selection of dams.
9. The estimates of the components of correlation between first and
second position indexes of the same bird and clutch in the production bred
flock are as follows: r = 0.162, which is the correlation that would
result were variation due only to environmental influence contributing
to differences of individual eggs and different clutches of individual birds;
rE = 1.013, which is the correlation that would result were variation due
only to those additional environmental influences contributing to variation
between birds; and rG = 0.909, which is the correlation that would
result were variation due only to genetic differences between birds.
10. The eight inbred lines have become differentiated with respect to
egg shape by genetic drift. No correlated response of egg shape to selection
for November egg weight or egg number as practiced in these lines occurred.
11. Inbreds were found to be more sensitive and the crosses less
sensitive to environmental effects than the more or less randomly bred
birds of the production-bred flock. It was also noted that the inbreds
appeared to be more sensitive to environmental variations than the
crosses for November egg weight and shank length.
_________________________

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#115352 - 01/07/16 07:00 AM Re: Long egg? [Re: Redcap]
Robbie Offline
Flock Leader

Registered: 01/19/15
Posts: 258
Loc: Ontario Canada
CJR and Redcap, thank you! That was the information I needed. Redcap thanks for posting the summaries, as I don't have access to those.
In this case I will keep the hen in my breeder flock, as she has other egg qualities that are good (dark and large) and outcross to another line. :-)

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#115354 - 01/07/16 09:32 AM Re: Long egg? [Re: Robbie]
Redcap Offline
Ruler of the Roost

Registered: 08/14/06
Posts: 954
Loc: Germany
_________________________

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#115355 - 01/07/16 10:39 AM Re: Long egg? [Re: Redcap]
Robbie Offline
Flock Leader

Registered: 01/19/15
Posts: 258
Loc: Ontario Canada
Thanks. Redcap is there a way to search the documents at kippenjungle (without the search function) if you are looking for a topic of interest, and the author(s) are unknown?
Are these documents different than the ones posted on the reference lists on this forum?


Edited by Robbie (01/07/16 10:42 AM)

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#115356 - 01/07/16 11:35 AM Re: Long egg? [Re: Robbie]
Redcap Offline
Ruler of the Roost

Registered: 08/14/06
Posts: 954
Loc: Germany
You can make a search with STRG + F plus search word on the main page.
http://documents.kippenjungle.nl/#home
The documents which are posted there, are without public access on the journal sites.
_________________________

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#115357 - 01/07/16 07:41 PM Re: Long egg? [Re: Redcap]
Robbie Offline
Flock Leader

Registered: 01/19/15
Posts: 258
Loc: Ontario Canada
OK thanks, that would be the Ctrl on my computer.

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