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 Influence of Sex-Linked Feathering Phenotypes of Parents and Progeny Upon Lymphoid Leukosis Virus Infection Status and Egg Production

1984 ◽  
Vol 63 (3) ◽  
pp. 401-413 ◽  
Author(s):  
DEWEY L. HARRIS ◽  
VERNON A. GARWOOD ◽  
PHILLIP C. LOWE ◽  
PATRICIA Y. HESTER ◽  
LYMAN B. CRITTENDEN ◽  
...  
Keyword(s):  
Virus Infection ◽  
Egg Production ◽  
Infection Status ◽  
Lymphoid Leukosis

Selection for Egg Production

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

scholarly journals Triple La Sota re‐vaccinations can protect laying chickens for 3 months against drop in egg production caused by velogenic viscerotropic Newcastle disease virus infection

2020 ◽  
Vol 6 (3) ◽  
pp. 470-476
Author(s):  
Harriet N. Okechukwu ◽  
Anthony A. Chukwuedo ◽  
Didacus C. Eze ◽  
Amarachukwu O. Igwe ◽  
John I. Ihedioha ◽  
...  
Keyword(s):  
Virus Infection ◽  
Newcastle Disease Virus ◽  
Disease Virus ◽  
Newcastle Disease ◽  
Egg Production ◽  
Newcastle Disease Virus Infection

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

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