scholarly journals Selection Response in a Divergent Selection Experiment for Birth Weight Variability in Mice Compared with a Control Line

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 920
Author(s):  
Nora Formoso-Rafferty ◽  
Katherine Natalia Chavez ◽  
Candela Ojeda ◽  
Isabel Cervantes ◽  
Juan Pablo Gutiérrez
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Laboratory Mouse ◽  
Selection Response ◽  
Divergent Selection ◽  
Suitable Model ◽  
Control Line ◽  
Selection Experiment ◽  
High Line ◽  
Third Line

Birth weight (BW) in animal production is an economically important trait in prolific species. The laboratory mouse (Mus musculus) is used as an experimental animal because it is considered a suitable model for prolific species such as rabbits and pigs. Two mouse lines were divergently selected for birth weight variability with a third line of non-selected control population of the same origin as the animals starting the experiment. The objective of this study was, therefore, to compare and evaluate the differential response of each line. The animals were from the 17th generation of both low and high BW variability lines of the divergent selection experiment, including in addition animals from the control line. The dataset contained 389 records from 48 litters of the high line, 734 records from 73 litters of the low line, and 574 records from 71 litters of the control line. The studied traits were as follows: the BW, the BW variance, the BW standard deviation, the BW coefficient of variation within-litter, the weaning weight (WW), the litter size at birth and at weaning, the weight gain, and the preweaning survival. The model included the line effect jointly with the parturition number and its interaction, the linear and quadratic LS as covariates except for the LS trait itself when analyzing litter traits, as well as the pup sex when analyzing individual traits. The low line had a lower BW and WW, but a higher litter size, and greater robustness owing to a higher survival at weaning. As a model of livestock animals, the findings from this experiment led to a proposal of selection for pig production that would combine an increase in litter size with higher survival and welfare. Compared with the control line, a much higher response was observed in the low variability line than in the high line, making it extremely satisfactory given that homogeneity provides advantages in terms of animal welfare and robustness.

scholarly journals Components of litter size in mice after 110 generations of selection

Reproduction ◽  
2004 ◽  
Vol 127 (5) ◽  
pp. 587-592 ◽  
Author(s):  
M Holt ◽  
O Vangen ◽  
W Farstad
Keyword(s):  
Litter Size ◽  
Late Pregnancy ◽  
Ovulation Rate ◽  
Control Line ◽  
Embryo Survival ◽  
High Line ◽  
Line Selection ◽  
Males And Females ◽  
The Mean ◽  
Standard Deviations

The aim of the present study was to evaluate how ovulation rate and survival rate through pregnancy had been affected by more than 110 generations of upwards selection on litter size in mice. The mean number of pups born alive was 22 in the high line (selected line) and 11 in the control line (an increase in 2.6 standard deviations). Selection on litter size increased ovulation rate by 4.6 standard deviations, and it is suggested that selection also increased embryonic mortality in late pregnancy. Embryo survival from ovulation until birth was 66% in the selected line and 69% in the control line, and the observed loss in litter size from day 16 of pregnancy until birth was possibly higher in the high line compared with the control line. Selection for higher litter size has significantly increased body weight in both males and females, as the mean weight at mating for the females was 46 g in the high line and 33 g in the control line respectively.

Genetic analyses of piglet survival and individual birth weight on first generation data of a selection experiment for piglet survival under outdoor conditions

2007 ◽  
Vol 2007 ◽  
pp. 65-65
Author(s):  
R. Roehe ◽  
N. P. Shrestha ◽  
W. Mekkawy ◽  
P. W. Knap ◽  
K. M. Smurthwaite ◽  
...  
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Genetic Improvement ◽  
First Generation ◽  
Genetic Parameters ◽  
Selection Experiment ◽  
Postnatal Mortality ◽  
Breeding Programmes ◽  
Potential Benefits ◽  
Piglet Survival

Peri- and postnatal mortality of piglets is reported to be around 20% and genetic improvement in piglet survival has great potential benefits in terms of animal welfare, economics and the environment. The indication of an unfavourable genetic correlation between litter size and survival in particular points to the importance of including piglet survival in those pig breeding programmes that currently only aim to increase litter size. Phenotypically, individual birth weight is closely associated with piglet survival (Roehe and Kalm, 2000). Genetic parameters for piglet survival traits and individual birth weight therefore need to be estimated in order to genetically improve piglet survival efficiency

Effect of selection for increased litter size on ovulation rate and embryo survival in sheep

1990 ◽  
Vol 1990 ◽  
pp. 32-32 ◽  
Author(s):  
J.P. Hanrahan
Keyword(s):  
Litter Size ◽  
Ovulation Rate ◽  
Control Line ◽  
Selection Experiment ◽  
Embryo Survival ◽  
Relative Contribution ◽  
Variation Data ◽  
Component Traits ◽  
Selection For ◽  
The Impact

Variation in litter size in sheep is essentially attributable to variation in ovulation rate and embryo survival. Genetic variation in litter size, both among and within breeds, is largely attributable to variation in ovulation rate. While there is evidence for genetic differences among breeds in embryo survival the contribution of this component to within breed variation appears to be minor (Hanrahan, 1982). The impact of selection based on litter size on its component traits should reflect the relative contribution of these components to within breed variation. Data from two lines of Galway sheep, a Control line and one selected for increased prolificacy (Hanrahan and Timon, 1978), have been used to provide evidence on this point.Details relating to the selection experiment which provided the data for the present study are in Hanrahan (1984). Briefly a flock of Galway sheep was assembled from industry sources (both pedigree and non-pedigree) between 1963 and 1965.

scholarly journals Correlated response in early embryonic development in rabbits selected for litter size variability

2017 ◽  
Vol 25 (4) ◽  
pp. 323 ◽  
Author(s):  
E. W. Calle ◽  
M. L. García ◽  
A. Blasco ◽  
M.J. Argente
Keyword(s):  
Embryonic Development ◽  
Litter Size ◽  
Divergent Selection ◽  
Lower Proportion ◽  
Ovulation Rate ◽  
Early Embryonic Development ◽  
Correlated Response ◽  
Phenotypic Variance ◽  
High Line ◽  
Size Variability

<p>A divergent selection experiment for litter size variability was carried out in rabbits. The litter size variability was estimated as the phenotypic variance of litter size within female. The aim of this study was to assess the effect of selecting for litter size variability on early embryonic development and survival after 7 generations of divergent selection (high and low variability lines). A total of 30 non-lactating multiparous does per line were used. The ovulation rate and early embryonic development were analysed using Bayesian methodology. Ovulation rate was not affected by the selection process. At 28 h of gestation, embryonic development and survival were similar in both lines. At 48 h of gestation, the majority of embryos in the high line were in the early morulae stage. The high line had a higher proportion of early morulae (79.54 vs. 53.43%; P=0.94) and a lower proportion of compacted morulae (20.46 vs. 46.57%; P=0.93%) than the low line. At 72 h of gestation, the high line had 1.59 fewer embryos than the more homogeneous line (P=0.85), due to reduced embryonic survival (0.60 vs. 0.74; P=0.93). The high line continued to show a higher proportion of early morulae (21.01 vs. 3.69%; P=0.93) and a lower proportion of compacted morulae and blastocysts (78.99 vs. 96.31%; P=0.94) than the low line at 72 h of gestation, indicative of reduced embryonic development. In conclusion, selection for homogeneity in litter size had a positive impact on embryonic traits.</p>

INFLUENCE OF BODY WEIGHT AND CHANGES IN BODY WEIGHT OF THE COW ON PREWEANING TRAITS OF THE CALF

1980 ◽  
Vol 60 (3) ◽  
pp. 599-607
Author(s):  
G. W. RAHNEFELD ◽  
R. J. PARKER ◽  
S. YODSERANEE ◽  
E. W. STRINGAM
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Average Daily Gain ◽  
Control Line ◽  
Selection Experiment ◽  
Weight Changes ◽  
Apparent Effect ◽  
Weaning Weight ◽  
Factors Affecting ◽  
Daily Gain

This study was designed to estimate and evaluate environmental factors affecting birth weight, weaning weight and preweaning average daily gain (ADG) of purebred Shorthorn calves from the control line of a selection experiment. Nine years of data consisted of 635 birth weight and 607 weaning weight records. Least squares analysis of variance revealed that sex of the calf was the most important source of variation: males averages 2.31 kg heavier at birth, were 14.3 kg heavier at weaning and gained 0.08 kg more per day from birth to weaning than females. Heavier cows in June, October, and December prior to parturition and at parturition produced heavier calves at birth. Heavier cows in October prior to parturition, at parturition, and in June or October following parturition produced calves which grew more rapidly from birth to weaning and were heavier at weaning. There was no apparent effect of cow weight changes before or after parturition on preweaning traits. Correlations of birth weight with weaning weight, preweaning ADG and cow weight at parturition were 0.56 ± 0.03, 0.43 ± 0.04 and 0.24 ± 0.04 respectively. Correlations of weaning weight and preweaning average daily gain with cow weights at parturition were 0.42 ± 0.04 and 0.40 ± 0.04. Correlations among cow weights in June, October, and December prior to parturition, at parturition, and in June and October following parturition were estimated.

The direct and maternal components of the response to divergent selection for yearling growth rate in angus cattle

1990 ◽  
Vol 51 (3) ◽  
pp. 505-513 ◽  
Author(s):  
R. M. Herd
Keyword(s):  
Growth Rate ◽  
Average Daily Gain ◽  
Divergent Selection ◽  
Daily Weight Gain ◽  
Control Line ◽  
Response To Selection ◽  
Direct Component ◽  
Angus Cattle ◽  
High Line ◽  
Selection For

ABSTRACTA crossmothering experiment was conducted to measure the direct and the maternal components of the response to divergent selection for yearling growth rate in beef cattle. The animals were from three closed lines of Angus cattle. Two lines had been selected since 1974 for either high (high-line) or low (low-line) average daily gain from birth to yearling, and the third line was maintained as a randomly bred control-line. A total of 221 female calves born between 1984 and 1987 was used in the crossmothering experiment, and an additional 113 cows bearing calves in 1988 were used to obtain more records of milk production.On average, high-line calves born in 1984-87 were 45 kg heavier at weaning (200 days of age) than low-line calves and 65 kg heavier at yearling age, corresponding to a proportional divergence in daily weight gain of 0·29 and 0·32 respectively. The direct component of the response to selection was 0·82 (s.e. 0-05) of the divergence in body weight at weaning and 0·89 (s.e. 0·05) at yearling age. The maternal component was 0·18 (s.e. 0·06) and 0·11 (s.e. 0·04) for weaning and yearling weight respectively. Over the years 1984-88, high-line dams produced 1·15 times the milk of low-line dams and only 1·03 times that of control-line dams. There were small differences in the composition of milk sampled in 1984 which resulted in the milk of high-line dams having a higher content of metabolizable energy (ME) than that of control-line dams. The ME in the milk consumed by the calves from the three selection lines was sufficient to fuel similar proportions of their pre-weaning growth and indicated that the expression of the maternal component of the selection response may be via small differences in the quantity and quality of the milk produced by the dams. Expression of the direct component appeared to be at least partially via differences in appetite of the calves. These results, together with results for sheep, mice and rats, show that the direct component of the response to selection for growth is much larger than the maternal component.

scholarly journals Phenotypic and genetic parameters and responses in temperament of silver fox cubs in a selection experiment for confident behaviour

2008 ◽  
Vol 15 (3) ◽  
pp. 340 ◽  
Author(s):  
H. KENTTÄMIES ◽  
M. NIKKILÄ ◽  
M. MIETTINEN
Keyword(s):  
Genetic Parameters ◽  
Selection Response ◽  
Selection Line ◽  
Control Line ◽  
Selection Experiment ◽  
Selection Differential ◽  
Genetic Response ◽  
Factors Affecting ◽  
Silver Fox ◽  
One Year

A selection experiment for more confident silver foxes was arranged to find out possibilities to obtain selection response in confidence. Variation in aggressiveness and ease of capture was also studied. Fixed factors affecting the traits were studied using WSYS program. Covariances for breeding values were estimated with REML and multitrait animal models using VCE4 and Pest programs. It appeared that males were more confident than females. Cubs born in small litters tended to be more confident, less aggressive and easier to capture compared to those born in greater litters. Cubs of one-year-old dams seemed to be more confident and easier compared to those of older dams. Moderate estimate of heritability was obtained for confidence (h2 = 0.22). During three years of selection, genetic response of 0.13 points was achieved in confidence in selection line compared to control line. A higher selection differential existed in males than females. Predicted response of 0.21 points was slightly higher than the estimated one. No heritability was observed in aggressiveness, while a low one existed in ease of capture (h2 = 0.07). No association between confidence and the other behaviour traits were found.;

scholarly journals SELECTION FOR BLOOD PRESSURE LEVELS IN MICE

Genetics ◽  
1974 ◽  
Vol 76 (3) ◽  
pp. 537-549
Author(s):  
Gunther Schlager
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Population Bottleneck ◽  
Control Line ◽  
Selected Lines ◽  
High Line ◽  
Selection For ◽  
Random Control

ABSTRACT Response to two-way selection for systolic blood pressure was immediate and continuous for about eight generations. In the twelfth generation, the High males differed from the Low males by 38 mmHG; the females differed by 39 mmHg. There was little overlap between the two lines and they were statistically significant from each other and from the Random control line. There appeared to be no more additive genetic variance in the eleventh and twelfth generations. Causes for the cessation of response are explored. This is probably due to a combination of natural selection acting to reduce litter sizes in the Low line, a higher incidence of sudden deaths in the High line, and loss of favorable alleles as both selection lines went through a population bottleneck in the ninth generation.—In the eleventh generation, the selected lines were used to produce F1, F2, and backcross generations. A genetic analysis yielded significant additive and dominance components in the inheritance of systolic blood pressure.

scholarly journals The impact of maternal genetic merit and country of origin on ewe reproductive performance, lambing performance and ewe survival

2021 ◽  
Author(s):  
N Fetherstone ◽  
N McHugh ◽  
T M Boland ◽  
F M McGovern
Keyword(s):  
New Zealand ◽  
Birth Weight ◽  
Litter Size ◽  
Country Of Origin ◽  
Reproductive Traits ◽  
Gestation Length ◽  
Genetic Merit ◽  
Genetic Groups ◽  
One Year ◽  
The Impact

Abstract The objective of this study was to investigate the impact of the ewe’s maternal genetic merit and country of origin (New Zealand or Ireland) on ewe reproductive, lambing and productivity traits. The study was performed over a four year period (2016 to 2019) and consisted of three genetic groups: high maternal genetic merit New Zealand (NZ), high maternal genetic merit Irish (High Irish) and low maternal genetic merit Irish (Low Irish) ewes. Each group contained 30 Suffolk and 30 Texel ewes, selected based on the respective national maternal genetic indexes; i.e. either the New Zealand Maternal Worth (New Zealand group) or the €uro-star Replacement index (Irish groups). The impact of maternal genetic merit on reproductive traits such as litter size; lambing traits such as gestation length, birth weight, lambing difficulty, mothering ability, and productivity traits such as the number of lambs born and weaned were analyzed using linear mixed models. For binary traits, the impact of maternal genetic merit on reproductive traits such as conception to first AI service; lambing traits such as dystocia, perinatal lamb mortality and productivity traits such as ewe survival were analyzed using logistic regression. New Zealand ewes outperformed Low Irish ewes for conception to first AI (P&lt;0.05) and litter size (P=0.05). Irish ewes were more likely to suffer from dystocia (6.84 (High Irish) and 8.25 (Low Irish) times) compared to NZ ewes (P&lt;0.001); birth weight and perinatal mortality did not differ between groups (P&gt;0.05). Lambs born from NZ ewes were 4.67 (95% CI: 1.89 to 11.55; P&lt;0.001) and 6.54 (95% CI: 2.56 to 16.71; P&lt;0.001) times more likely to stand up and suckle unassisted relative to lambs born from High or Low Irish ewes, respectively. New Zealand and High Irish ewes had a greater number of lambs born and weaned throughout the duration of the study compared to their Low Irish counterparts (P&lt;0.001). New Zealand ewes tended to be more likely to survive from one year to the next compared to Low Irish ewes (P=0.07). Irish ewes of high maternal genetic merit outperformed their Low counterparts in total number of lambs born and weaned per ewe, but performance did not differ across other traits investigated. This highlights the importance of continuous development of the Irish maternal sheep index to ensure favourable improvements in reproductive, lambing and productivity traits at farm level. Overall, results demonstrate the suitability of NZ genetics in an Irish production system.

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