scholarly journals RESPONSE TO SELECTION FOR BODY WEIGHT AND EGG WEIGHT IN CHICKENS

Genetics ◽  
1967 ◽  
Vol 55 (2) ◽  
pp. 219-231
Author(s):  
Michael F Festing ◽  
A W Nordskog
Keyword(s):  
Body Weight ◽  
Response To Selection ◽  
Egg Weight ◽  
Selection For

Simulation of Response to Selection for Body Weight in Rainbow Trout

1981 ◽  
Vol 31 (4) ◽  
pp. 426-432 ◽  
Author(s):  
Sampo Sirkkomaa ◽  
Ulf B. Lindström
Keyword(s):  
Body Weight ◽  
Rainbow Trout ◽  
Response To Selection ◽  
Selection For

scholarly journals EFFECTS OF ANCESTRAL X IRRADIATION FOLLOWED BY RANDOM MATING ON BODY WEIGHT OF RATS

Genetics ◽  
1977 ◽  
Vol 86 (4) ◽  
pp. 849-860
Author(s):  
Daniel Gianola ◽  
A B Chapman ◽  
J J Rutledge
Keyword(s):  
Body Weight ◽  
Random Mating ◽  
Rapid Response ◽  
Response To Selection ◽  
Previous Evidence ◽  
Selection Responses ◽  
Inbred Rats ◽  
X Irradiation ◽  
Selection For ◽  
Variance Estimates

ABSTRACT Effects of nine generations of 450r per generation of ancestral spermatogonial X irradiation of inbred rats on body weight were examined. After six generations of random mating (avoiding inbreeding) following the termination of irradiation, descendants of irradiated males (R) were significantly lighter than their controls (C) at 3 and 6 weeks, but not at 10 weeks of age. However, differences in growth between R and C populations were small. Among-litter and within-litter variance estimates were generally larger in the R lines than in the C lines, suggesting that selection responses would be greater in R than in C lines. In conjunction with previous evidence—obtained during the irradiation phase of the experiment—this suggested that more rapid response to selection for 6-week body weight, in particular, might accrue in the R lines.

RESPONSE TO SELECTION FOR BODY WEIGHT OR FEED EFFICIENCY IN MICE TESTED ON CORN, RYE AND WHEAT DIETS

1986 ◽  
Vol 66 (2) ◽  
pp. 389-397
Author(s):  
R. I. McKAY ◽  
R. J. PARKER ◽  
W. GUENTER
Keyword(s):  
Body Weight ◽  
Feed Efficiency ◽  
Mass Selection ◽  
Response To Selection ◽  
Initial Weight ◽  
Commercial Diet ◽  
Final Weight ◽  
Dc Line ◽  
Selection For ◽  
Seven Generations

Mass selection for adjusted feed efficiency (AFE, g gain/g feed) and adjusted body weight (ABW, g) of male mice was practiced for seven generations on each of three diets: corn, rye and wheat. The three experimental diets, fed between 21 and 35 d, were isocaloric (approximately 16.5 MJ GE kg−1) and isonitrogenous (CP approximately 13%). A common commerical diet (PC) was fed at all other times. With each diet two control lines, randomly mated, were tested on either the experimental diets (DC) or a commercial diet (PC). Selection was based upon linear adjustment to a common initial weight (10 g) for either final weight (ABW) or feed efficiency (AFE) measured between 21 and 35 d of age. Response was determined as a deviation from the appropriate DC line. All animals were placed in specially designed individual cages during the test period. Half-sib estimates of heritability in the PC line were 0.13(± 0.11) for ABW and 0.19(± 0.10) for AFE. Half-sib estimates pooled across lines and diets were 0.16(± 0.07) for ABW and 0.28(± 0.07) for AFE. Realized heritabilities for ABW were 0.24(± 0.06), 0.06(± 0.07) and 0.14(± 0.06) for the corn, rye and wheat diets, respectively. Response to selection for AFE was poor with the highest heritability obtained on the wheat diet (h2 = 0.13 ± 0.02). Key words: Selection, mice, body weight, feed efficiency, diets

CORRELATED RESPONSES IN EGG QUALITY TRAITS TO SELECTION FOR EARLY BODY WEIGHT IN MEAT-TYPE CHICKENS

1972 ◽  
Vol 14 (3) ◽  
pp. 477-482 ◽  
Author(s):  
V. Buvanendran ◽  
E. S. Merritt
Keyword(s):  
Body Weight ◽  
Egg Quality ◽  
Correlated Response ◽  
Quality Traits ◽  
Correlated Responses ◽  
Egg Weight ◽  
Shell Color ◽  
Blood Spots ◽  
Selection For ◽  
Meat Type

The correlated responses in egg quality traits to selection for high early body weight were studied in seven meat-type populations comprising five selected and two control lines. Traits studied were specific gravity, egg weight, albumen height, Haugh units, shell color, egg shape, shell roughness, wrinkling and asymmetry, and incidence of blood spots, meat spots and double yolks. Significant (P < 0.05 or < 0.01) correlated changes, as determined by the regression of correlated response (egg quality traits) on primary response (body weight), were obtained for egg weight, albumen height, Haugh units, asymmetry of shell and blood spots. All but blood spots increased with selection for high body weight. Shell color showed a consistent trend towards a darker color with increasing body weight. Scores for roughness of shell and, with one minor exception, the incidence of double yolks, also showed consistent trends (positive) with increasing body weight. Estimates of genetic correlations, derived directly from intra-line genetic analyses of the six pedigreed populations in the experiment, were in most cases in reasonable agreement with realized estimates.

scholarly journals RESPONSE TO SELECTION AT TWO TEMPERATURES FOR FAST AND SLOW GROWTH FROM FIVE TO NINE WEEKS OF AGE IN POULTRY

Genetics ◽  
1981 ◽  
Vol 97 (2) ◽  
pp. 443-456
Author(s):  
B B Bohren ◽  
J R Carson ◽  
J C Rogler
Keyword(s):  
Body Weight ◽  
First Generation ◽  
Slow Growth ◽  
Response To Selection ◽  
White Leghorn ◽  
Common Environment ◽  
Genotype By Environment ◽  
Hot Environment ◽  
Two Temperatures ◽  
Selection For

ABSTRACT Cornell Control White Leghorn chicks were grown in a common environment to five weeks of age and selected for fast and slow gain in body weight from five to nine weeks of age at two temperatures, 21.1° (cold) and 32.2° (hot), during which time a constant 50% relative humidity was maintained. All lines were tested each generation in both temperature environments. Selection continued for four generations, with a second replicate started six weeks after the first replicate in each generation. In the hot environment, a 20% reduction (104 g) in five-to-nine-week weight gain was found. The responses to selection for fast and slow growth were symmetrical except in the first generation, when an outbreak of bronchitis confounded selection for body weight with selection for disease resistance and allowed little gain in the slow lines. No genotype-by-environment interactions were found, indicating that selection in either direction in either selection temperature produced equal responses in either test temperature. This suggests that any interactions observed between the growth of strains in tropical vs. temperate climates must be due to some difference between these environments other than the temperature differences studied.

scholarly journals Fertility, Body Weight and Survivability of Two Lines of Broiler Stock under Selection

2021 ◽  
Vol 43 (2) ◽  
pp. 19-27
Author(s):  
A. K Olutunmogun ◽  
A.U Umar, ◽  
I. A Adeyinka ◽  
E. O Adejoh-Ubani ◽  
B.I Nwag ◽  
...  
Keyword(s):  
Body Weight ◽  
Survival Rate ◽  
Broiler Chicks ◽  
Hybrid Strain ◽  
Egg Weight ◽  
Broiler Breeder ◽  
Pooled Data ◽  
Correlation And Regression Analysis ◽  
Breeder Hens ◽  
Selection For

This study was conducted to evaluate the performance of two lines of broiler breeders under selection. The traits of interest were fertility, body weight and survival rate. A total of 120 day-old broiler chicks were hatched from two lines of broiler breeder chickens under selection (Sire and Dam lines). The chicks were hatched from a population of breeder hens and cocks with a mating ratio of 1 broiler cock to 6 broiler hens (1:6). Eggs were collected and pedigreed according to the lines and sire information. The eggs were weighed on a Camry model digital sensitive scale in grams. Eggs were set and hatched in a Buckeye incubator. Each hatched chick was tagged and weighed at hatching and then weekly up to 8 weeks. Data were analyzed using general linear model (GLM). Correlation and regression analysis were based on pooled data from both lines. Results showed that the lines differed with respect to fertility (67.67% and 83.00%), hatchability (77.79 and 49.00) and survival rate (77.78 and 94.14).Also changes in body weight increased as their ages increased with the dam line being superior. There was a low R2 value of between 0.05 – 0.33 when egg weight and hatch weight were pooled and considered as independent variables. In conclusion the lines were superior to each other differently as the sire line had better egg weight and hatchability while the dam line was better in fertility, survival rate and body weight performance. This variation in traits can be used in selection for hybrid strain in the broiler

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