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.

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.

Relationships among uterine and placental factors in prolific ewes and their relevance to variations in foetal weight

1980 ◽  
Vol 30 (1) ◽  
pp. 115-124 ◽  
Author(s):  
S. M. Rhind ◽  
J. J. Robinson ◽  
I. McDonald
Keyword(s):  
Litter Size ◽  
Late Pregnancy ◽  
Ovulation Rate ◽  
Total Weight ◽  
Under Nutrition ◽  
Foetal Mortality ◽  
The Mean ◽  
The Individual

ABSTRACTObservations were made on the distribution of ovulations between the two ovaries, the distribution of foetuses between the two uterine horns, the total numbers of cotyledonary burrs, and the weights and numbers of foetal cotyledons for each foetus in 80 Finnish Landrace × Dorset Horn ewes killed between 50 and 145 days of gestation. While ovulations were randomly distributed between right and left ovaries, viable foetuses were more evenly distributed between right and left uterine horns. Migration of embryos between the horns contributed to this relative balance but early foetal mortality, which increased with ovulation rate, tended to upset it. The mean number of foetal cotyledons per foetus depended on litter size and distribution, and at any fixed litter size was substantially reduced in those ewes with six or more ovulations. Foetal weights were also relatively low in these ewes. The total weight of cotyledons per foetus decreased by about 12% for each increase of one in number of foetuses, as compared with a 20% decrease in number of cotyledons but only a 7 to 11 % decrease in the weight of the individual foetuses. Comparisons between foetuses within the same litter led to similar trends in the ratios of cotyledon numbers, cotyledon weights and foetal weights. It is suggested that the presence of some very small lambs in large litters should not be attributed to maternal under-nutrition in late pregnancy.

Genetics of reproduction in the rabbit.

2021 ◽  
pp. 212-233
Author(s):  
Miriam Piles ◽  
Maria Antonia Santacreu ◽  
Agustin Blasco ◽  
Jun Pablo Sanchez
Keyword(s):  
Litter Size ◽  
Reproductive Cycle ◽  
Genetic Determinism ◽  
Ovulation Rate ◽  
Biological Processes ◽  
Embryo Survival ◽  
Male And Female ◽  
Fetal Survival

Abstract This chapter describes the genetic determinism of all traits involved in male and female reproductive performances in rabbits. All traits related to the underlying biological processes leading to the mating outcome, as well as some of its general features, such as the homogeneity of the reproductive performances, are considered (semen and ejaculate characteristics, ovulation rate, fertility, embryo survival, fetal survival and litter size). Different parameters of fertility and litter size are discussed, including the contribution of both sexes to each phase of the reproductive cycle.

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.

The effect of energy or protein supplementation on embryo survival rate in ewes

1995 ◽  
Vol 1995 ◽  
pp. 55-55
Author(s):  
M.G. Diskin ◽  
J.P. Hanrahan
Keyword(s):  
Survival Rate ◽  
Litter Size ◽  
Protein Supplementation ◽  
Ovulation Rate ◽  
Reproductive Efficiency ◽  
Protein Supplement ◽  
Embryo Survival ◽  
Rumen Undegradable Protein

Embryo survival rate is a major factor determining litter size and overall reproductive efficiency in sheep. In sheep, as ovulation rate increases the proportion of embryos surviving decreases. There is evidence, from cattle, that feeding a rumen-undegradable protein supplement enhances embryo survival rate. The objective of this experiment was to determine the effect on embryo survival rate in high prolific ewes of feeding an energy or protein supplement.

Late pregnancy ewe feeding and lamb performance in early life. 1. Pregnancy feeding levels and perinatal lamb mortality

1979 ◽  
Vol 29 (3) ◽  
pp. 393-399 ◽  
Author(s):  
A. M. Khalaf ◽  
D. L. Doxey ◽  
J. T. Baxter ◽  
W. J. M. Black ◽  
J. FitzSimons ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Litter Size ◽  
Live Weight ◽  
Late Pregnancy ◽  
Metabolizable Energy ◽  
Daily Weight Gain ◽  
Early Lactation ◽  
The Mean ◽  
Metabolizable Energy Intake ◽  
Immunoglobulin Levels

ABSTRACTOne hundred and thirty-nine Scottish Half bred ewes were studied during the last 8 weeks of pregnancy, through parturition and early lactation. They were divided, on the basis of their metabolizable energy intake during this period, into low (483 MJ/ewe; L), medium (742 MJ/ewe; M) or high (974 MJ/ewe; H) feeding groups.Ewe weight change (from mating to 12 h post lambing) was directly related to nutritional level and the number of lambs born, e.g. L ewes with triplets lost a mean 13·8 kg, while H ewes with single lambs gained 14·3 kg.Lamb birth weight and perinatal lamb mortality levels were affected by ewe nutrition and litter size. L twins weighed 19% less at birth than H twins; L triplets weighed 26% less than H triplets. The mortality rate of L twins was 23% greater than M twins; L triplets exceeded the H triplet mortality rate by 87%.Ewe energy feeding during late pregnancy affected the mean daily weight gain of lambs for at least 3 weeks after birth. H single, twin and triplet lambs grew 12%, 15% and 16% faster than M lambs and 19%, 31 % and 31 % faster than L lambs respectively.The H group produced 33 % more lamb live weight at 3 weeks of age for every lamb born than did the L group.Lamb serum immunoglobulin levels were related to litter size but did not reflect the differences in ewe feeding during late pregnancy.

256 LINES OF PIGS SELECTED FOR COMPONENT TRAITS OF LITTER SIZE EXHIBIT DIFFERENTIAL GENE REGULATION AT THE ONSET OF EMBRYO (TROPHECTODERM) ELONGATION

2006 ◽  
Vol 18 (2) ◽  
pp. 235 ◽  
Author(s):  
J. R. Miles ◽  
L. A. Blomberg ◽  
B. A. Freking ◽  
K. A. Zuelke
Keyword(s):  
Gene Expression ◽  
Immune Modulation ◽  
Interleukin 1 ◽  
Regulatory Protein ◽  
Constitutive Expression ◽  
Cell Interaction ◽  
Ovulation Rate ◽  
Control Line ◽  
Embryo Survival ◽  
Cytochrome P450scc

Significant embryonic (<18%) loss occurs in the pig as the pre-implantation embryo undergoes a dramatic morphological change from ovoid (8-10 mm) at gestational Day 11 to a long, thin filament (<150 mm) by Day 12. Lines of pigs selected for increased uterine capacity have improved embryonic survival, whereas pigs selected for increased ovulation rate have decreased embryo survival. Alterations in the expression of genes that play key roles in embryo elongation and maternal recognition of pregnancy may reflect differences in embryo survival observed in these lines of pigs. The objective of the current study was to evaluate the expression level of transcripts involved in developmentally important processes, such as steroidogenesis, cellular differentiation, cell-cell interaction, and immune modulation, at the onset of porcine embryo elongation (gestational Day 11) in control animals and lines selected for increased ovulation rate or uterine capacity. Total RNA was isolated from Day 11 ovoid embryos, and gene expression was measured via real-time PCR. Data were analyzed for analysis of variance using GLM procedures. Expression of steroidogenic acute regulatory protein mRNA was decreased (P = 0.02) in embryos from the ovulation rate and uterine capacity lines compared with controls. Similarly, expression of cytochrome P450scc and aromatase mRNA were decreased (P < 0.003) in embryos from the ovulation rate and uterine capacity lines, compared with the control line. Interestingly, 17�-hydroxylase mRNA expression was decreased (P = 0.0004) only in embryos from the ovulation rate line compared with the control and uterine capacity lines. In contrast, expression of cytokeratin-8 and -18 mRNA were increased (P < 0.02) in embryos from the uterine capacity and ovulation rate lines, compared with controls. Expression of galectin 1 mRNA was increased (P = 0.02) in embryos from the uterine capacity line, compared with the ovulation rate line. Expression of interleukin-1 receptor type 1 mRNA was increased (P = 0.03) in embryos from the uterine capacity line, compared with both the control and the uterine capacity lines. Constitutive expression of 17�-hydroxysteroid dehydrogenase, stratifin, and interleukin-1� mRNA were observed in embryos from all lines. These results demonstrate altered gene expression in embryos from pigs selected for increased uterine capacity and ovulation rate compared with controls, and may contribute to differences observed in embryo survival between these lines of pigs.

Genetic studies of prolificacy in New Zealand sheep

1998 ◽  
Vol 67 (2) ◽  
pp. 289-297 ◽  
Author(s):  
G. H. Davis ◽  
C. A. Morris ◽  
K. G. Dodds
Keyword(s):  
Litter Size ◽  
Heritability Estimate ◽  
Ovulation Rate ◽  
The Other ◽  
Relationship Matrix ◽  
Research Station ◽  
Embryo Survival ◽  
Genetic Studies ◽  
Average Litter Size ◽  
Likelihood Model

AbstractData on ovulation rate, embryo survival and litter size have been analysed from the 1988-96 records collected at AgResearch's Woodlands Research Station on 2180 elite (highly prolific) ewes of three breeds: Romney, Coopworth and Perendale. The Romneys included a subgroup found to carry the sex-linked Inverdale high prolificacy gene. Foundation animals for all breeds were screened on high litter size (lambs born, alive or dead, per ewe lambing) from industry flocks. Prior to being transferred to Woodlands between 1979 and 1984, their average litter size was 2·66. Ovulation rates for descendants of the foundation ewes averaged 2·15 (Romney), 2·43 (Coopworth), 2·15 (Perendale) and 2·96 for the Romney subgroup carrying the Inverdale gene. Embryo survival averaged 0·84 except for a low value in Inverdales (0·76). Using a restricted maximum likelihood model, with full relationship matrix, the within-breed heritability of ovulation rate over all ages and breeds (excluding Inverdale) was 0·14 (s.e. 0·03), with repeatability 0·26 (s.e. 0·02). Litter size averaged 1-80 (Romney), 2·05 (Coopworth), 1·76 (Perendale) and 2·17 (Inverdale). The heritability estimate for litter size (excluding Inverdale) was 0·073 (s.e. 0·018), from data for all ages. The genetic correlation between ovulation rate and litter size was 0·91 (s.e. 0·08). The standard deviation for ovulation rate in the Inverdales was 1·75 times as great as the average of the other three breeds. Embryo survival to term for ewes conceiving to two, three or four ovulations averaged 0·89, 0·77 and 0·64, respectively, and was significantly different among breeds fP < 0·001). The greater ovulation rate in Inverdales than Romneys was sufficient to explain the Inverdale effect on reduced embryo survival. The highest embryo survival was observed in the Coopworth breed (P < 0·001).

Short-term undernutrition and prenatal mortality in young and mature Merino ewes

1975 ◽  
Vol 84 (1) ◽  
pp. 113-117 ◽  
Author(s):  
A. J. Mackenzie ◽  
T. N. Edey
Keyword(s):  
Ovulation Rate ◽  
Control Group ◽  
Corpora Lutea ◽  
Short Term ◽  
Embryo Survival ◽  
Body Weights ◽  
Cycle Lengths ◽  
The Mean ◽  
Group 2 ◽  
The Right

SUMMARYPrenatal mortality was examined in 74 primiparous Merino ewes which, after hand mating to fertile rams on the second oestrus following synchronization, were allocated to two groups. One group of 38 ewes was confined to yards and restricted to approximately 30% of their maintenance requirement for 14 days while the other group of 36 remained at pasture. The degree and timing of prenatal loss was assessed by corpora lutea counts, pregnancy diagnosis about day 40, returns to service and lambing records.The mean ovulation rate was 1·06 and the 19-day non-return rate was 87·8%. Pregnancy failed in a higher proportion of the underfed ewes (45·0%) than in the control ewes (30·8%) but this difference did not reach significance. Of the ewes returning to service, significantly more did so with cycles longer than 19 days in the underfed group (9/12) than in the control group (2/8), indicating that in the latter stages, the treatment may have been detrimental to embryo survival.In a second experiment, ovulation rate and prenatal mortality, assessed as in the first experiment, were studied in 85 mature Merino ewes subjected to the following nutritional treatments: HH, control; HL, 30% submaintenance feeding for 14 days following mating; LH, 15% submaintenance feeding for 7 days prior to mating; LL, both submaintenance treatments.Acute undernutrition prior to mating (LH) had no effect on ovulation rate or prenatal mortality. Ovulation rates were low over all groups (mean 1·09) and thus precluded any valid examination of ovulation rate and body weight relationships. The right ovary was significantly more active in producing ova than the left in all groups (P < 0·05). Although ova wastage was apparently higher in. the post-mating undernutrition groups (HL, 44%; LL, 48%; LH, 50%) than in the control group (HH, 35%), the differences were not significant. An increased incidence of extended (> 19 days) first-return cycle lengths in group LL provided some evidence of induced prenatal mortality.In so far as the experiments can be considered together, they indicate that if body weights are comparable, primiparous 1½-year-old ewes are not necessarily more susceptible than mature ewes to prenatal mortality induced by severe short-term undernutrition.

scholarly journals Ovarian Transcriptomic Analysis Reveals Differential Expression Genes Associated with Cell Death Process after Selection for Ovulation Rate in Rabbits

Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1924
Author(s):  
Marta Serna-García ◽  
Rosa Peiró ◽  
Eva Serna ◽  
María Antonia Santacreu
Keyword(s):  
Cell Death ◽  
Litter Size ◽  
Ovarian Tissue ◽  
Ovulation Rate ◽  
Death Process ◽  
Meat Production ◽  
Control Line ◽  
Differential Expression Genes ◽  
Cell Death Process ◽  
Rabbit Meat

Litter size is an essential trait in rabbit meat production but with low heritability. A selection experiment for ovulation rate has been performed for 10 generations to improve litter size in rabbits. The selected line increased two ova more than the control line but nevertheless a negative correlation was observed with prenatal survival. A transcriptomic study was performed, using microarrays, in ovarian tissue from females belonging to the selected line and the control line. Our results showed 1357 differential expressed genes and nineteen potential biomarkers associated with prenatal mortality, which could explain differences between litter size in rabbits. Cell death was the most relevant process.

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