Direct response to selection for post-weaning net feed intake in mice and correlated responses in post-weaning growth, intake, gross digestibility and body composition

2004 ◽  
Vol 44 (5) ◽  
pp. 489 ◽  
Author(s):  
T. E. Hughes ◽  
W. S. Pitchford
Keyword(s):  
Body Composition ◽  
Feed Intake ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Response To Selection ◽  
Correlated Responses ◽  
Direct Response ◽  
Selection For ◽  
Seven Generations ◽  
Daily Gain

Seven generations of divergent selection on a phenotypic index of net feed in mice produced a realised heritability estimate of 0.27 ± 0.07. Despite small negative genetic correlations of net feed intake with daily gain and liveweight, correlated responses in these economically important traits were negligible. Still, more efficient animals tended to be fatter during the early post-weaning phase. Gross digestibility was also affected, which may have implications for the overall energy balance of a biological system.

Estimates of genetic parameters for pre-weaning and post-weaning growth traits of Chios lambs

1980 ◽  
Vol 30 (2) ◽  
pp. 271-276 ◽  
Author(s):  
A. P. Mavrogenis ◽  
A. Louca ◽  
O. W. Robison
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Weaning Weight ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Daily Gain

ABSTRACTData on 792 Chios lambs born during the 1972/73 and 1973/74 lambing seasons were used to estimate genetic and phenotypic parameters for birth weight, weaning weight, age at weaning, pre-weaning daily gain, body weight at 5, 10, 15 and 20 weeks of age, and postweaning daily gain. Body weight at 15 weeks of age had the highest heritability estimate (0·73 ± 0·17) and that of post-weaning daily gain was also high (0·56 ± 0·15). Selection for either weight at 15 weeks or post-weaning daily gain would be expected to yield a greater response than selection for pre-weaning daily gain or weaning weight. Genetic correlations among weights and/or gains were positive (approximately 0·20). Phenotypic correlations among weights and gains were generally higher than genetic correlations. However, the correlation between pre— and post-weaning daily gain was small (0·08). Likewise, post-weaning daily gain had low correlations with all weights before 10 weeks. Age at weaning had moderate negative associations with all weights but a very low positive correlation with post-weaning daily gain.

RESPONSE TO SELECTION FOR WEIGHT-PER-DAY-OF-AGE IN RAMBOUILLET AND ROMNELET SHEEP

1975 ◽  
Vol 55 (1) ◽  
pp. 1-8 ◽  
Author(s):  
J. A. VESELY ◽  
H. F. PETERS
Keyword(s):  
Genetic Correlations ◽  
Response To Selection ◽  
Correlated Responses ◽  
Weaning Weight ◽  
Two Generations ◽  
Selection For ◽  
Heritability Estimates

Responses to selection for weight-per-day-of-age (WPDA) to about 170 days in Rambouillet and Romnelet sheep over 5 yr, comprising two generations, were measured by two methods. Correlated responses in weaning weight (WW) at about 100 days, and postweaning gain (PWG) for 70 days were also estimated. The estimates of annual genetic increases in WPDA were quite similar in both breeds and from both methods. The improvements of this trait in Rambouillet and Romnelet were estimated as 9.7 and 6.0 g/yr from method 1, and 9.1 and 7.8 g/yr from method II. Estimates of correlated responses in PWG obtained by both methods and in both breeds were close to expected estimates, but correlated responses in WW appeared to be overestimated. Heritability estimates for WPDA using paternal half-sibs were 0.20 for Rambouillet and 0.18 for Romnelet. All genetic correlations among the three traits were positive. Realized heritabilities for WPDA were 0.28 and 0.20 in Rambouillet and Romnelet by method I, and 0.26 in both breeds by method II.

scholarly journals DIRECT RESPONSE TO SELECTION FOR POSTWEANING GAIN IN THE RAT

Genetics ◽  
1975 ◽  
Vol 80 (1) ◽  
pp. 171-189
Author(s):  
R L Baker ◽  
A B Chapman ◽  
R T Wardell
Keyword(s):  
Relative Magnitude ◽  
Realized Heritability ◽  
Response To Selection ◽  
Direct Response ◽  
Selected Lines ◽  
History Of ◽  
Regression Techniques ◽  
Selection For ◽  
Rats And Mice ◽  
Seven Generations

ABSTRACT The effectiveness of selection for 3–9-week gain was examined in a population of rats with a history of past selection for high 3–9-week gain. Lines were selected for high (U line) and low (D line) 3–9-week gain with two replicates of each line. Two randomly selected lines were also kept, one originating from the same base population as the two selected lines (R line) and the other originating from a population that had been randomly mated for the previous 27 generations (C line). Two replicates of each of these lines were kept. After seven generations of selection, a randomly selected line (relaxed line) was formed from each of the two upward- and each of the two downward-selected lines. Results have been presented for 13 generations of selection. The environmental trend for 3–9-week gain, as indicated by the randomly selected R and C lines, was consistently negative in all four lines. Realized heritabilities calculated by deviating the response to selection from the trend in the R or C lines resulted in non-significantly higher values in the D lines than the U lines. Six generations of relaxation of selection indicated no effect of natural selection in the U lines or the D lines. The relative magnitude of the drift, error and common environmental variances were estimated by the methods given by Hill (1971). The estimates of these parameters then led to calculation of the degree of bias in the sampling variances of the realized heritability estimates. As was predicted by Hill (1971), estimates of the variance of realized heritabilities obtained by using standard regression techniques were less than those obtained using Hill's formulae. The results are discussed in relation to other similar studies with rats and mice.

scholarly journals MASS SELECTION FOR POST-WEANING GROWTH IN SWINE: II. RESPONSE TO SELECTION

1971 ◽  
Vol 51 (2) ◽  
pp. 497-502 ◽  
Author(s):  
G. W. RAHNEFELD
Keyword(s):  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Average Daily Gain ◽  
Mass Selection ◽  
Realized Heritability ◽  
Response To Selection ◽  
Components Of Variance ◽  
Selection For ◽  
Seven Generations ◽  
Daily Gain

Recurrent mass selection for post-weaning average daily gain was practiced for seven generations in a population of Lacombe swine. Response to selection was positive, but the observed response was estimated to be only 0.33 of the predicted. The pooled estimate of additive genetic variance was 0.0013 ± 0.0002. Realized heritability was 0.126 ± 0.029. The pooled estimate of heritability obtained from components of variance and parent-offspring regression was 0.377 ± 0.058. Litter size was positively correlated with average daily gain (0.14 piglet per generation). No significant effects of selection in reducing additive genetic variance were observed.

Selection for components of efficient lean growth rate in pigs 2. Selection pressure applied and direct responses in a Landrace herd

1994 ◽  
Vol 59 (2) ◽  
pp. 263-269 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran
Keyword(s):  
Growth Rate ◽  
Genetic Correlations ◽  
Correlated Response ◽  
Selection Line ◽  
Control Line ◽  
Direct Response ◽  
Lean Growth ◽  
Ad Libitum ◽  
Selection For ◽  
Ad Libitum Feeding

AbstractResponses to divergent selection for lean growth rate with ad-libitum feeding (LGA), for lean food conversion (LFC) and for daily food intake (DFI) in Landrace pigs were studied. Selection was practised for four generations with a generation interval ofl year. A total of 2642 pigs were performance tested in the high, low and control lines, with an average of 37 boars and 39 gilts performance tested per selection line in each generation. The average within-line inbreeding coefficient at generation four was equal to 0·04. There was one control line for the DFI and LFC selection groups and another control line for the LGA selection group. Animals were performance tested in individual pens with mean starting and finishing weights of 30 kg and 85 kg respectively with ad-libitum feeding. The selection criteria had phenotypic s.d. of 32, 29 and 274 units, for LGA, LFC and DFI, respectively, and results are presented in phenotypic s.d.Cumulative selection differentials (CSD) were 5·1, 4·5 and 5·5 phenotypic s.d. for LGA, LFC and DFI, respectively. Direct responses to selection were 1·4,1·1 and 0·9 (s.e. 0·20) for LGA, LFC and DFI. In each of the three selection groups, the CSD and direct responses to selection were symmetric about the control lines. The correlated response in LFC (1·1, s.e. 0·19) with selection on LGA was equal to the direct response in LFC. In contrast, the direct response in LGA was greater than the correlated response (0·7, s.e. 0·18) with selection on LFC. There was a negative correlated response in DFI (-0·6, s.e. 0·18) with selection on LFC, but the response with selection on LGA was not significant (0·2, s.e. 0·16).Heritabilities for LGA, LFC and DFI ivere 0·25, 0·25 and 0·18 (s.e. 0·03), when estimated by residual maximum likelihood, with common environmental effects of 0·12 (s.e. 0·02). Genetic correlations for LFC with LGA and DFI were respectively positive (0·87, s.e. 0·02) and negative (-0·36, s.e. 0·09), while the genetic correlation between DFI and LGA was not statistically different from zero, 0·13 (s.e. 0·10). Selection on components of efficient lean growth has identified LGA as an effective selection objective for improving both LGA and LFC, without a reduction in DFI.

Selection for rate and efficiency of lean gain in Hereford cattle 1. Selection pressure applied and direct responses

1990 ◽  
Vol 51 (1) ◽  
pp. 23-34 ◽  
Author(s):  
R. A. Mrode ◽  
C. Smith ◽  
R. Thompson
Keyword(s):  
Genetic Parameters ◽  
Control Line ◽  
Correlated Responses ◽  
Direct Response ◽  
Lean Growth ◽  
Hereford Cattle ◽  
Frozen Semen ◽  
Phenotypic Standard Deviation ◽  
Selection For ◽  
Selection Of

ABSTRACTSelection of bulls for rate and efficiency of lean gain was studied in a herd of Hereford cattle. There were two selection lines, one selected for lean growth rate (LGR) from birth to 400 days and the other for lean food conversion ratio (LFCR) from 200 to 400 days of age, for a period of 8 years. A control line bred by frozen semen from foundation bulls was also maintained. Generation interval was about 2·4 years and average male selection differentials, per generation were 1·2 and — 1·1 phenotypic standard deviation units for LGR and LFCR respectively.Genetic parameters and responses to selection were estimated from the deviation of the selected lines from a control line and by restricted maximum likelihood (REML) techniques on the same material. Realized heritabilities were 0·40 (s.e. 0·12) for LGR and 0·40 (s.e. 0·13) for LFCR using the control line. Corresponding estimates from REML were 0·42 (s.e. 0·10) and 0·37 (s.e. 0·14). The estimate of the genetic correlation between LGR and LFCR was about — 0·69 (s.e. 0·12) using REML.The estimates of direct annual genetic change using deviations from the control were 3·6 (s.e. 1·3) g/day for LGR and — 0·14 (s.e. 0·07) kg food per kg lean gain for LFCR. Corrsponding estimates from REML were similar but more precisely estimated. The correlated responses for LFCR in the LGR line was higher than the direct response for LFCR.

scholarly journals PSVIII-38 Late-Breaking Abstract: Estimating genetic parameters of feed efficiency traits in American mink

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 347-347
Author(s):  
Pourya Davoudi ◽  
Duy Ngoc Do ◽  
Guoyu Hu ◽  
Siavash Salek Ardestani ◽  
Younes Miar
Keyword(s):  
Body Weight ◽  
Genetic Correlation ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
American Mink ◽  
Genetic Correlations ◽  
Final Body Weight ◽  
Selection For

Abstract Feed cost is the major input cost in the mink industry and thus improvement of feed efficiency through selection for high feed efficient mink is necessary for the mink farmers. The objective of this study was to estimate the heritability, phenotypic and genetic correlations for different feed efficiency measures, including final body weight (FBW), daily feed intake (DFI), average daily gain (ADG), feed conversion ratio (FCR) and residual feed intake (RFI). For this purpose, 1,088 American mink from the Canadian Center for Fur Animal Research at Dalhousie Faculty of Agriculture were recorded for daily feed intake and body weight from August 1 to November 14 in 2018 and 2019. The univariate models were used to test the significance of sex, birth year and color as fixed effects, and dam as a random effect. Genetic parameters were estimated via bivariate models using ASReml-R version 4. Estimates of heritabilities (±SE) were 0.41±0.10, 0.37±0.11, 0.33±0.14, 0.24±0.09 and 0.22±0.09 for FBW, DFI, ADG, FCR and RFI, respectively. The genetic correlation (±SE) was moderate to high between FCR and RFI (0.68±0.15) and between FCR and ADG (-0.86±0.06). In addition, RFI had low non-significant (P > 0.05) genetic correlations with ADG (0.04 ± 0.26) and BW (0.16 ± 0.24) but significant (P < 0.05) high genetic correlation with DFI (0.74 ± 0.11) indicating that selection for lower RFI will reduce feed intake without adverse effects on the animal size and growth rate. The results suggested that RFI can be implemented in genetic/genomic selection programs to reduce feed intake in the mink production system.

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

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