scholarly journals An Empirical Test of Part-Record Selection for Egg Production

1956 ◽  
Vol 35 (6) ◽  
pp. 1349-1355 ◽  
Author(s):  
I. Michael Lerner ◽  
Everett R. Dempster
Keyword(s):  
Egg Production ◽  
Empirical Test ◽  
Selection For ◽  
Record Selection

Selection for Egg Production

1960 ◽  
Vol 16 (1) ◽  
pp. 36-46
Author(s):  
Fred Skaller
Keyword(s):  
Egg Production ◽  
Selection For

scholarly journals Polyandry enhances offspring survival in an infanticidal species

2009 ◽  
Vol 6 (1) ◽  
pp. 24-26 ◽  
Author(s):  
Ines Klemme ◽  
Hannu Ylönen
Keyword(s):  
Mating Systems ◽  
Multiple Mating ◽  
Empirical Test ◽  
Myodes Glareolus ◽  
Offspring Survival ◽  
Bank Voles ◽  
Female Counterstrategy ◽  
Fitness Benefits ◽  
Selection For ◽  
Genetic Fitness

The adaptive significance of polyandry is an intensely debated subject in sexual selection. For species with male infanticidal behaviour, it has been hypothesized that polyandry evolved as female counterstrategy to offspring loss: by mating with multiple males, females may conceal paternity and so prevent males from killing putative offspring. Here we present, to our knowledge, the first empirical test of this hypothesis in a combined laboratory and field study, and show that multiple mating seems to reduce the risk of infanticide in female bank voles Myodes glareolus . Our findings thus indicate that females of species with non-resource based mating systems, in which males provide nothing but sperm, but commit infanticide, can gain non-genetic fitness benefits from polyandry.

Genetic parameters for egg weight v. age curve, and other egg production and egg weight traits, in synthetic lines of chickens

1983 ◽  
Vol 34 (1) ◽  
pp. 85 ◽  
Author(s):  
BH Yoo ◽  
BL Sheldon ◽  
RN Podger
Keyword(s):  
Standard Deviation ◽  
Genetic Correlation ◽  
Egg Production ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Egg Mass ◽  
Control Line ◽  
Egg Weight ◽  
Egg Number ◽  
Selection For

An exponential curve, W = P-Qexp(- Rt), where W is egg weight at age t, was fitted to egg weights of individual pullets, and genetic parameters were estimated for P, Q and R, the residual standard deviation and other egg weight and egg production characters. The data consisted of records collected over six generations on more than 4000 pullets in two selection lines and a control line which originated from a synthetic gene pool of White Leghorn x Australorp crosses. The half-sib and offspring-on-parent regression estimates of heritability pooled over the lines were 0.23 and 0.33 for P, 0.14 and 0.20 for Q, and 0.14 and 0.25 for R. Genetic correlations were estimated to be -0.10 between P and Q, -0.46 between P and R, and 0.90 between Q and R. These estimates suggest that the egg weight v. age curve may be modified to increase the proportion of eggs in desirable weight grades and reduce the incidence of oversized eggs later in the production year. The genetic correlation between mean weight of first 10 eggs and egg weight at 62 weeks of age was estimated to be 0.68, further suggesting that early egg weight may be improved partly independently of late egg weight. The heritability estimates of egg mass output were not higher than those of egg number in spite of the highly heritable average egg weight being an important component of egg mass, probably because of the negative genetic correlation (r = -0.49) between egg number and average egg weight. The standard deviation of individual pullet's egg weights was moderately heritable and genetically correlated positively with egg weight characters and negatively with egg production; these estimates were consistent with the responses to selection for reduced egg weight variability observed elsewhere

scholarly journals Lymphoid Leukosis Virus Infection: Effects on Production and Mortality and Consequences in Selection for High Egg Production

1980 ◽  
Vol 59 (10) ◽  
pp. 2165-2178 ◽  
Author(s):  
J.S. GAVORA ◽  
J.L. SPENCER ◽  
R.S. GOWE ◽  
D.L. HARRIS
Keyword(s):  
Virus Infection ◽  
Egg Production ◽  
Lymphoid Leukosis ◽  
Selection For

scholarly journals Effect of Selection for Weight of Early Eggs on Egg Production Traits in Japanese Quail

2015 ◽  
Vol 9 (4) ◽  
pp. 179-190 ◽  
Author(s):  
Mohamed Bahie El- Deen ◽  
Ayman A. Nour ◽  
Waleed S. El- Tahawy ◽  
Hala A. Fouad
Keyword(s):  
Japanese Quail ◽  
Egg Production ◽  
Production Traits ◽  
Selection For

scholarly journals Effect of feathering alleles (K/k+) on laying performance, hatchability parameters and some body measurements in two lines of white plymouth rock hens

2012 ◽  
Vol 28 (3) ◽  
pp. 405-414 ◽  
Author(s):  
N. Mincheva ◽  
M. Lalev ◽  
M. Oblakova ◽  
P. Hristakieva ◽  
I. Ivanova
Keyword(s):  
Egg Production ◽  
Shape Index ◽  
Substantial Effect ◽  
Body Measurements ◽  
Production Traits ◽  
Broiler Production ◽  
Live Body Weight ◽  
Laying Performance ◽  
Lower Fertility ◽  
Selection For

The study aimed to investigate the effects of sex - linked feathering alleles on laying performance, hatchability parameters and body measurements in hens from two White Plymouth Rock lines (line L and line K) used as maternal lines in broiler production. Four groups of 18-week-old hens were formed, two of each line, with genotype K/W (slow feathering) and k+/W (rapid feathering) respectively. Groups of line L included 72 hens divided into 6 boxes with 1 rooster per 12 hens, whereas line K groups comprised 96 hens of each genotype, housed in 8 boxes with one rooster per 12 hens, totally 192 birds. The K locus alleles had no significant effect on egg production traits (p>0.05). The presence of slow feathering allele resulted in lower fertility and hatchability of set eggs in both studied lines (p<0.05). A substantial effect of feathering rate alleles was observed with respect to the egg shape index (p<0.05), eggshell thickness (p<0.001) and albumen index (p<0.05). The presence of the slow feathering allele resulted in lower live body weight of birds from line K at the age of 36 weeks (p<0.05), but in longer thighs (p<0.01) and metatarsi (p<0.001) in both lines. The selection for creation of slow feathering lines for feather sexing purposes should take into consideration the effect of the K gene on studied traits.

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