scholarly journals Population Size as a Factor in Response to Selection for Eight-Week Body Weight in White Leghorns

1982 ◽  
Vol 61 (7) ◽  
pp. 1273-1278 ◽  
Author(s):  
C.G. VASQUEZ ◽  
B.B. BOHREN
Keyword(s):  
Body Weight ◽  
Population Size ◽  
Response To Selection ◽  
White Leghorns ◽  
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

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

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.

Sign in / Sign up

Export Citation Format

Share Document