Effects of divergent selection for incidence of tibial dyschondroplasia (TD) on purebred and crossbred performance. 1. TD incidence and calcium and phosphorus plasma concentrations

2000 ◽  
Vol 41 (5) ◽  
pp. 562-565 ◽  
Author(s):  
S. Yalçin ◽  
X. Zhang ◽  
L.M. Christa ◽  
G.R. McDaniel ◽  
D.L. Kuhlers
Keyword(s):  
Plasma Concentrations ◽  
Divergent Selection ◽  
Tibial Dyschondroplasia ◽  
Calcium And Phosphorus ◽  
Selection For

scholarly journals Responses to divergent selection for plasma concentrations of insulin-like growth factor-1 in mice

1989 ◽  
Vol 53 (3) ◽  
pp. 187-192 ◽  
Author(s):  
H. T. Blair ◽  
S. N. McCutcheon ◽  
D. D. S. Mackenzie ◽  
P. D. Gluckman ◽  
J. E. Ormsby ◽  
...  
Keyword(s):  
Growth Factor ◽  
Plasma Concentrations ◽  
Selection Criterion ◽  
Divergent Selection ◽  
Correlated Response ◽  
Insulin Like Growth Factor ◽  
Family Selection ◽  
Selection For ◽  
High Control ◽  
And Control

SummaryA divergent selection experiment with mice, using plasma concentrations of insulin-like growth factor-1 (IGF-1) at 42 days of age as the selection criterion, was undertaken for 7 generations. Lines were not replicated. To obtain sufficient plasma for the IGF-1 assay, blood from four individuals was volumetrically bulked to obtain a litter mean IGF-1 concentration. This necessitated the use of between family selection. Although inbreeding accumulated in a linear fashion in each of the high, control and low lines, the rates were different for each line (3·6, 1·6 and 5·3% per generation for the high, control and low lines, respectively). As a consequence, the effects of selection and inbreeding are confounded in this experiment. Divergence between the high and low lines in plasma concentrations of IGF-1 continued steadily until generation 5. In generations 6 and 7, there was a reduced degree of divergence and this contributed towards the low realized heritability value of 0.15 ± 0.12. Six-week liveweight showed a steady positive correlated response to selection for or against plasma concentrations of IGF-1 until generation 4 (high-low difference = 1·7 g = 12%). In generation 5, a substantial drop in 6-week liveweight in the low line relative to both the high and control lines occurred (high-low difference, 3·9; g, 25%). This difference was maintained until generation 7.This experiment suggests that genetic variation exists at 6 weeks of age in plasma concentrations of IGF-1 in mice. Furthermore, genetic covariation between plasma IGF-1 concentrations and liveweight at 6 weeks of age is likely to be positive. Further experiments have been initiated to examine these theories.

Divergent Selection for In Vitro Dry Matter Digestibility in Smooth Bromegrass 1

Crop Science ◽  
1986 ◽  
Vol 26 (6) ◽  
pp. 1123-1126 ◽  
Author(s):  
N. J. Ehlke ◽  
M. D. Casler ◽  
P. N. Drolsom ◽  
J. S. Shenk
Keyword(s):  
Dry Matter ◽  
Divergent Selection ◽  
Smooth Bromegrass ◽  
Dry Matter Digestibility ◽  
Selection For

Effects of Divergent Selection for Growth on Carcass Traits in Japanese Quails

2014 ◽  
Vol 42 (2) ◽  
pp. 51-56
Author(s):  
Khairy M. El–Bayomi ◽  
Mahmoud S. El-Tarabany ◽  
Mohammed A.F. Nasr ◽  
El-Shimaa M. Roushdy
Keyword(s):  
Carcass Traits ◽  
Divergent Selection ◽  
Japanese Quails ◽  
Selection For
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