scholarly journals Estimation of changes in genetic parameters in selected lines of mice using REML with an animal model. 2. Body weight, body composition and litter size

Heredity ◽  
1992 ◽  
Vol 69 (4) ◽  
pp. 361-371 ◽  
Author(s):  
B K Beniwal ◽  
I M Hastings ◽  
R Thompson ◽  
W G Hill
Keyword(s):  
Animal Model ◽  
Body Composition ◽  
Body Weight ◽  
Litter Size ◽  
Genetic Parameters ◽  
Selected Lines

Estimates Of Genetic Parameters For Economic Traits In West African Dwarf Goat

2021 ◽  
Vol 19 ◽  
pp. 114-119
Author(s):  
I. K. Odubote ◽  
J. O. Akinokun
Keyword(s):  
Body Weight ◽  
Litter Size ◽  
Genetic Parameters ◽  
West African ◽  
Economic Traits ◽  
West African Dwarf ◽  
West African Dwarf Goat ◽  
Heritability Estimates ◽  
Size At Birth ◽  
Birth Body Weight

Records of 848 West African Dwarf goat kids and 220 kiddings over a period of eight years (1982-1989) were analysed. The records were used to provide heritability and repeatability estimates for litter size at birth, kidding interval (repeatability estimate alone) and body weight at birth, weaning, 3 months, 6 months, 9 months and 1 year of age. Heritability estimates of 0.28±0.005, 0.18±0.003, 0.14±0.003, 0.29±0.005, 0.11±0.003 and 0.17±0.004 were obtained for litter size at birth, body weight at birth, and at weaning, 3 months, 6 months, and 9 months of age respectively. Corresponding repeatability estimates were slightly higher than the heritability estimates. However, repeatability estimates of 0.04±0.030 was obtained for kidding interval.

Factors affecting reproductive performance and estimates of genetic parameters of litter size in Horro sheep

2002 ◽  
Vol 139 (1) ◽  
pp. 79-85 ◽  
Author(s):  
S. ABEGAZ ◽  
G. DUGUMA ◽  
E. NEGUSSIE ◽  
U. GELMESA ◽  
F. TEREFE ◽  
...  
Keyword(s):  
Animal Model ◽  
Litter Size ◽  
Age Structure ◽  
Reproductive Performance ◽  
Genetic Improvement ◽  
Genetic Parameters ◽  
Factors Affecting ◽  
Optimal Weight ◽  
Annual Means ◽  
Lambing Rate

Conception and lambing rate, and litter size were studied on data from a flock of Horro sheep. The CATMOD and GLM procedures of SAS were used for the analysis of these traits. A sire, direct additive genetic and a repeatability animal model were employed to obtain estimates of heritability and repeatability for litter size. The results obtained showed that year of mating, age and weight of ewes at mating and number of previous parities had significantly (P<0.01) affected the rate of conception and lambing while weight of rams at mating has shown no significant effect (P>0.05). An increase in both conception and lambing rates was observed with the increase in weight of ewes up to about 36 kg and declined thereafter. Ewes which previously had no or one parity had lower conception and lambing rates compared with ewes in later parities. However, a decline in both conception and lambing rates was also observed in old ewes. Year of lambing, parity and weight of ewes at mating had a highly significant (P<0.01) effect on litter size. The overall mean litter size in the flock was 1.34 with annual means ranging from 1.18 to 1.55. Litter size increased with parity from 1.26 in primiparous ewes to 1.44 for ewes of parities five and above. With respect to weight of ewes at mating, litter size increased by 2.5% for each kg increase in weight at mating. The estimates of direct heritability (h2) for litter size were 0.17, 0.11 and 0.06 under the sire, direct animal and repeatability models. Repeatability was estimated to be 0.12. Since heritability and repeatability estimates of litter size are low, genetic improvement by selection may not bring sizeable impact in increasing litter size. Therefore flock management for optimal age structure and optimal weight of ewes at mating should receive due consideration to improve rates of conception, lambing and litter size in Horro sheep.

scholarly journals Effects of selection on growth, body composition and food intake in mice: II. Correlated responses in reproduction

1984 ◽  
Vol 44 (1) ◽  
pp. 73-85 ◽  
Author(s):  
Forbes D. Brien ◽  
Gillian L. Sharp ◽  
William G. Hill ◽  
Alan Robertson
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Food Intake ◽  
Litter Size ◽  
Reproductive Performance ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Primary Reason ◽  
Correlated Responses ◽  
Fat Percentage

SummaryFemale reproductive performance is reported in mice selected for ten generations for one of three criteria: either appetite (A), fat percentage (F) or total lean mass (P). For each criterion lines were selected for high (H) or low (L) performance, with contemporary unselected controls (C). In the A and P lines, litter size changed in the direction of the selected criterion, the changes being larger and more rapidly established in the A than in the P lines. At generation 10, the differences in litter size between high and low lines were 2·6 live young born in the A lines, and 1·0 live young born in the P lines. The differences in 6-week weight between the high and low lines were 3·5 g in the A lines, 6·5 g in the P lines. Changes in ovulation rate were the primary reason for changes in litter size, the differences between the high and low lines being 3·8 corpora lutea for the A lines, and 3·1 corpora lutea for the P lines. Fitting body weight at mating as a covariate within lines in the analysis of ovulation rate and live foetus number removed the differences between the high and low selected P lines, but not those in the A lines. The high and low selected A and P lines did not differ in prenatal survival. There were no consistent differences in litter size, ovulation rate or pre-natal survival in the F lines.

Estimation of variance components for body weight of grasscutters (Thryonomys swinderianus) using a repeatability model

2020 ◽  
Vol 47 (2) ◽  
pp. 33-36
Author(s):  
I. Udeh
Keyword(s):  
Animal Model ◽  
Body Weight ◽  
Variance Components ◽  
Genetic Parameters ◽  
Growth Potential ◽  
Likelihood Method ◽  
Mass Selection ◽  
Thryonomys Swinderianus ◽  
Estimate Variance ◽  
Estimation Of Variance

Genetic parameters for growth and other economically important traits of grasscutters are scant in literature. Therefore, the aim of this study was to estimate variance components,heritability and repeatability of body weight of grasscutters using restricted maxim um likelihood method in a repeatability animal model. Sixteen grasscutter families were used for the study. Each family was made up of one male and four females. Each grasscutter has four repeated records giving a total of 320. The pedigree consisted of 80 animals, progenies of 16 sires and 16 dams. Fixed factors included in the model were family and sex. The WOMBAT program was used for the analysis. The heritability of body weight of grasscutters ranged from 0.23±0.04 to 0.68±0.10, thus implying that mass selection will be appropriate for this population. The repeatability estimates ranged from 0.82±0.08 to 0.93±0.11. It can be concluded that the number of body weight records was a good indicator of the animal's growth potential and that mass selection will be reliable.

Selection in Guinea Pigs: I. Estimation of Phenotypic and Genetic Parameters for Litter Size and Body Weight

1983 ◽  
Vol 56 (4) ◽  
pp. 814-819 ◽  
Author(s):  
B. Quijandria ◽  
Lily Chauca de Zaldivar ◽  
O. W. Robison
Keyword(s):  
Body Weight ◽  
Litter Size ◽  
Guinea Pigs ◽  
Genetic Parameters

Estimation of genetic parameters for body weight traits and litter size of Moghani sheep, using a Bayesian approach via Gibbs sampling

2010 ◽  
Vol 148 (3) ◽  
pp. 363-370 ◽  
Author(s):  
N. GHAVI HOSSEIN-ZADEH ◽  
M. ARDALAN
Keyword(s):  
Body Weight ◽  
Gibbs Sampling ◽  
Litter Size ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Genetic Effect ◽  
Residual Effects ◽  
Pedigree Information ◽  
Body Weights

SUMMARYThe objective of the present study was to estimate genetic parameters for body weights at different ages and litter size (LS) in Moghani sheep. Traits included were birth weight (BW), 3 months weight (3MW), 6 months weight (6MW), 9 months weight (9MW), yearling weight (YW) and LS. The data of 6659 lambing records and pedigree information used in the current programme were collected at the Breeding Station of Moghani sheep (Ardebil province, Iran) during 1987–2005. Different linear and threshold animal models with additive genetic, maternal genetic, maternal permanent environmental and residual effects were implemented by Gibbs sampling (GS) methodology. A single GS chain with 150 000 rounds was generated by the MTGSAM program. The posterior means of genetic parameters were estimated based on the 1300 samples that were left after elimination of 20 000 rounds in the burn-in period and 100 rounds of each thinning interval. Posterior mean estimates of direct heritability were 0·29, 0·13, 0·14, 0·10, 0·31 and 0·10, while those of maternal heritabilities were 0·29, 0·08, 0·11, 0·06, 0·10 and 0·17 for BW, 3MW, 6MW, 9MW, YW and LS, respectively. Genetic correlations among the growth traits and LS were negative for direct genetic and maternal genetic effects. Therefore, selection for increased growth or LS may have a negative genetic effect on the other traits. The medium to high negative estimates of direct–maternal correlations for body weight traits or LS suggest that it would be difficult to improve direct and maternal growth ability jointly for Moghani sheep.

scholarly journals Estimation of changes in genetic parameters in selected lines of mice using REML with an animal model. 1. Lean mass

Heredity ◽  
1992 ◽  
Vol 69 (4) ◽  
pp. 352-360 ◽  
Author(s):  
B K Beniwal ◽  
I M Hastings ◽  
R Thompson ◽  
W G Hill
Keyword(s):  
Animal Model ◽  
Lean Mass ◽  
Genetic Parameters ◽  
Selected Lines
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