Variation in ovulation rate and litter size of Cambridge sheep

1996 ◽  
Vol 62 (3) ◽  
pp. 489-495 ◽  
Author(s):  
I. Ap Dewi ◽  
J. B. Owen ◽  
A. El-Sheikh ◽  
R. F. E. Axford ◽  
M. Beigi-Nassiri
Keyword(s):  
Litter Size ◽  
Genetic Correlations ◽  
Selection Criterion ◽  
Ovulation Rate ◽  
Ewe Lamb

AbstractOvulation rate (OR) and litter size (LS) were recorded in a flock of Cambridge sheep from 1984 to 1994 and from 1976 to 1994 respectively. There were 1516 and 2480 OR and LS records with means of 3·2 and 2·5 respectively. There was considerable variation in results between years ranging from 2·2 to 3·2 for LS and from 2·8 to 4·2 for OR. Ewe lamb OR was affected by year of recording, some years having higher OR than others. Rearing type (single, twin or triplet) also affected ewe lamb OR, twins having lower OR than both singles and triplets. Ewe lamb OR decreased with later date of birth reflecting a lower age at OR counting. Ewe lamb LS was affected by year of recording and there was also an interaction between date of birth and year indicating that OR decreased with later date of birth in some years but not in others. OR of adult ewes was affected by year of recording which also interacted with age (2, 3 and 4). Generally, OR increased with age but this trend was not observed in all years. LS of adult ewes was significantly affected by year and increased with ewe age (2, 3 and 4). Heritability and repeatability were determined for ewe lamb OR and LS and adult ewe OR and LS in univariate and two-trait analyses using DFREML. Heritabilities of ewe lamb OR (0·18 to 0·21) and LS (0·05 to 0·08) were lower than corresponding adult ewe values for OR (0·19 to 0·34) and LS (0·19 to 0·22). Ewe OR had a lower repeatability (0·43 to 0·55) than LS (0·30 to 0·80). High genetic correlations (>0·9) were obtained for combinations of ewe lamb OR, ewe lamb LS, adult ewe OR and adult ewe LS. The importance of analysing ewe lamb and ewe records separately is discussed as is the value of ewe lamb OR as a selection criterion.

scholarly journals Genetic studies of ovulation rate in the mouse

1969 ◽  
Vol 13 (1) ◽  
pp. 25-46 ◽  
Author(s):  
R. B. Land ◽  
D. S. Falconer
Keyword(s):  
Litter Size ◽  
Genetic Correlations ◽  
Ovulation Rate ◽  
Realized Heritability ◽  
Laboratory Mice ◽  
Response Curves ◽  
Genetic Studies ◽  
Induced Ovulation ◽  
Selection For ◽  
High Control

Genetic and physiological studies of ovulation rate, both natural and induced, in a random bred population of laboratory mice led to the following results.(1) The heritability of natural ovulation rate in nulliparous females was 22±19%, estimated from the correlation between paternal half-sibs.(2) Selection applied to natural ovulation in primiparous females led to a response in both directions, with a realized heritability of 31% (h2 within litters = 0·18 ± 0·013). The number of eggs shed by the High, Control and Low lines after 12 generations were respectively 21, 16 and 14.(3) Selection applied to ovulation induced by 4 i.u. of PMS led also to a response in both directions, with a realized heritability of 22% (h2 within litters = 0·11 ± 0·038). The induced ovulation rates of the High, Control and Low lines after 12 generations were respectively 29, 19 and 14 eggs.(4) PMS-equivalents were calculated from dose-response curves, and were found to be nearly the same in all lines except the line selected for high natural ovulation rate, which had a PMS-equivalent nearly double that of the Control. From this it was inferred that the increase of ovulation rate resulting from selection for high natural ovulation was due to an increased FSH activity, whereas the changes of ovulation rate resulting from selection for low natural ovulation and for both high and low induced ovulation were due to changes of ovarian sensitivity.(5) Genetic correlations, estimated from correlated responses to selection, were: (i) between natural and induced ovulation in primiparous females, 0·33; (ii) between primiparous and nulliparous females in natural ovulation, 0·46; (iii) between primiparous and nulliparous females in induced ovulation, 0·82.(6) The selection for induced ovulation produced changes in litter size following natural ovulation that were nearly equal to the changes in natural ovulation rate. The selection for natural ovulation, however, produced no clear changes of litter size.

The effects of dietary fibre and puberty induction method on ovarian activity of gilts

1996 ◽  
Vol 1996 ◽  
pp. 145-145
Author(s):  
V L Glasgow ◽  
A H Stewart ◽  
S A Edwards
Keyword(s):  
Litter Size ◽  
Dietary Fibre ◽  
Ovulation Rate ◽  
Ovarian Activity ◽  
Induction Method ◽  
High Level

In commercial systems it is highly desirable that gilts are synchronised into a predictable first heat. The use of PMSG/hCG injections (PG 600) has met with some success inducing a synchronised fertile oestrus and slightly increased ovulation rate (Schilling and Cerne, 1972) in gilts and anoestrus sows. Diets containing a high proportion of dietary fibre may influence litter size in gilts (Stewart et al, 1995). The aim of this study was to determine the effect of a high level of dietary fibre on oestrus expression and ovulation rate of gilts synchronised with exogenous gonadotrophins (PG600) or given daily boar stimulus.

THE ACCUMULATIVE EFFECT OF FINNSHEEP BREEDING IN CROSSBREEDING SCHEMES: REPRODUCTIVE PERFORMANCE

1988 ◽  
Vol 68 (1) ◽  
pp. 69-81 ◽  
Author(s):  
MOHAMED H. FAHMY ◽  
JACQUES J. DUFOUR
Keyword(s):  
Body Weight ◽  
Mortality Rate ◽  
Key Words ◽  
Litter Size ◽  
Reproductive Performance ◽  
Conception Rate ◽  
Ovulation Rate ◽  
Genetic Groups ◽  
Linear Regressions ◽  
Size At Birth

Reproductive performance and body weight were studied on 361 ewes, representing Finnsheep (F), DLS (a population of 1/2 Dorset, 1/4 Leicester, 1/4 Suffolk) and seven combinations ranging from 1/8 to 7/8 Finnsheep breeding. Conception rate in yearlings was 61.5% for DLS compared to 89.0% for F with the crosses being intermediate. Conception rate in older ewes was similar in the different genetic groups (avg. 94%). Ovulation rate and litter size at birth of DLS ewes were 1.72 and 1.44 lambs, which was less than half those of F ewes (3.51 and 2.86 lambs, respectively). Both traits increased progressively with an increase in F breeding in crosses and with advances in age. DLS ewes weaned 1.22 lambs compared to 2.03 lambs for F ewes and 1.84 lambs for 4/8 F ewes. The heaviest litters at weaning (31.7 kg) were raised by 4/8 F ewes, followed by 7/8 F (30.8 kg) while those raised by DLS ewes weighed 23.0 kg and F ewes 29.1 kg. Percentage of ova lost per ewe mated averaged 24% and ranged between 18% (DLS and 1/8 F) and 29% (6/8 F). About 3.6% of lambs were born dead and a further 13.8% died before weaning. Preweaning mortality rate was highest in F (22.9%) and lowest in 3/8 F (9.4%). Average kilograms of lambs weaned per ewe exposed was highest in 4/8 F (27.6 kg) followed by F (26.0 kg), whereas that of DLS was the lowest at 18.1 kg. The 4/8 F cross showed 25% heterosis in kg of lambs weaned per ewe exposed and 52.5% increase over DLS. Significant positive linear regressions were calculated for ovulation rate, litter size and preweaning mortality rate on proportion of Finnsheep breeding in crosses. The relation was quadratic for percent ova lost and lamb mortality at weaning. Yearling DLS females weighted 36 kg compared to 44 kg for F yearlings. However, at 5 yr of age DLS ewes weighed 62 kg, 5 kg heavier than F ewes. The heaviest ewes at all ages were the 4/8 F (45 kg at 1 yr, 65 kg at 5 yr). Key words: Reproduction, DLS sheep, Finnsheep, crossbreeding, heterosis, repeatabilities

scholarly journals Active immunization against the proregions of GDF9 or BMP15 alters ovulation rate and litter size in mice

Reproduction ◽  
2012 ◽  
Vol 143 (2) ◽  
pp. 195-201 ◽  
Author(s):  
C Joy McIntosh ◽  
Steve Lawrence ◽  
Peter Smith ◽  
Jennifer L Juengel ◽  
Kenneth P McNatty
Keyword(s):  
Litter Size ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Cross Reactivity ◽  
Full Length ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Immunization Group

The transforming growth factor β (TGFB) superfamily proteins bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9), are essential for mammalian fertility. Recent in vitro evidence suggests that the proregions of mouse BMP15 and GDF9 interact with their mature proteins after secretion. In this study, we have actively immunized mice against these proregions to test the potential in vivo roles on fertility. Mice were immunized with either N- or C-terminus proregion peptides of BMP15 or GDF9, or a full-length GDF9 proregion protein, each conjugated to keyhole limpet hemocyanin (KLH). For each immunization group, ovaries were collected from ten mice for histology after immunization, while a further 20 mice were allowed to breed and litter sizes were counted. To link the ovulation and fertility data of these two experimental end points, mice were joined during the time period identified by histology as being the ovulatory period resulting in to the corpora lutea (CL) counted. Antibody titers in sera increased throughout the study period, with no cross-reactivity observed between BMP15 and GDF9 sera and antigens. Compared with KLH controls, mice immunized with the N-terminus BMP15 proregion peptide had ovaries with fewer CL (P<0.05) and produced smaller litters (P<0.05). In contrast, mice immunized with the full-length GDF9 proregion not only had more CL (P<0.01) but also had significantly smaller litter sizes (P<0.01). None of the treatments affected the number of antral follicles per ovary. These findings are consistent with the hypothesis that the proregions of BMP15 and GDF9, after secretion by the oocyte, have physiologically important roles in regulating ovulation rate and litter size in mice.

The effect of melatonin treatment during the seasonal anoestrus on the superovulatory response and embryo production of high-prolificacy Rasa Aragonesa ewes before culling

2003 ◽  
Vol 2003 ◽  
pp. 82-82
Author(s):  
F. Forcada ◽  
J.A. Abecia ◽  
J.A. Valares
Keyword(s):  
Embryonic Development ◽  
Breeding Season ◽  
Litter Size ◽  
Direct Effect ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Melatonin Treatment ◽  
Embryo Production ◽  
Spring Equinox

The efficacy of melatonin implants inserted around the spring equinox to improve fertility and ovulation rate or litter size in Mediterranean ewes has been previously reported (Chemineau et al., 1996; Forcada et al., 2002a.), indicating the ability of the hormone to regulate the hypothalamic activity (Viguié et al., 1995). Moreover, a direct effect of melatonin on corpora lutea and embryonic development has been also reported (Wallace et al., 1988; Abecia et al., 2002). The use of prolific Rasa Aragonesa (RA) ewes (a Mediterranean breed) before culling as embryo donors has been previously tested in the breeding season (Forcada et al., 2002b.). The aim of this experiment was to improve embryo production during the seasonal anoestrus period in selected superovulated RA ewes at the end of their reproductive lives through the use of melatonin.

scholarly journals Litter size components traits in two Algerian rabbit lines

2021 ◽  
Vol 29 (1) ◽  
pp. 51
Author(s):  
Rafik Belabbas ◽  
Maria de la Luz García ◽  
Hacina AinBaziz ◽  
Ali Berbar ◽  
Maria José Argente
Keyword(s):  
Body Weight ◽  
Litter Size ◽  
Principal Components ◽  
Local Population ◽  
The Body ◽  
Ovulation Rate ◽  
Phenotypic Correlation ◽  
Limiting Factor ◽  
Corpora Lutea ◽  
Synthetic Line

<p>The aim of this study was to estimate the limiting litter size components in rabbit females from a Synthetic line (n=32) and a Local population (n=34). Ovulation rate, number of implanted and live embryos were counted by laparoscopy at 12 d after mating. Prolificacy (total newborn, number born alive and mortality) and embryonic, foetal and prenatal survival at day of birth of the 3<sup>rd</sup> gestation were measured. The analysed traits were body weight of the female at mating, ovulation rate, implanted, live and resorbed embryos, embryonic, foetal and prenatal survival, as well as total newborn, number born alive and mortality at birth. Synthetic line females had a higher ovulation rate compared to the Local population (11.03±0.23 vs. 8.41±0.23 corpora lutea; <em>P</em>&lt;0.0001). Synthetic line displayed a higher number of implanted embryos (10.00±0.25 vs. 7.85±0.25 embryos; <em>P</em>&lt;0.0001). No difference was found between groups for number of resorbed embryos. Similar embryonic, foetal and prenatal survival rates were reported between the Synthetic line and the Local population. Additionally, total newborn was higher in the Synthetic line than in the Local population (+1.46 kits; <em>P</em>&lt;0.05). A principal components analysis was performed. The first four principal components (PC) explained more than 90% of the total variation in both lines. Total newborn, number born alive and live embryos were the main variables defining the 1<sup>st</sup> PC. Resorbed embryos and foetal survival were located in the 2<sup>nd</sup> PC. Ovulation rate and embryonic survival were the predominant variables defining the 3<sup>rd</sup> PC. The body weight of females was located in the 4<sup>th</sup> PC. The phenotypic correlation between total newborn and its components were high and positive in both lines, except for ovulation rate and total newborn, where it was moderate in Synthetic line. In conclusion, the females from Synthetic line have a higher total newborn than those from Local population, as a consequence of a higher number of released oocytes and embryos that successfully reach implantation. However, a higher uterine crowding in Synthetic line seems to limit survival of foetuses that reach term of gestation, while ovulation rate is the principal limiting factor of total newborn in Local population.</p>

scholarly journals Estrus reaction of gilts as selection criteria for litter size

2009 ◽  
Vol 25 (5-6-1) ◽  
pp. 535-538
Author(s):  
V. Vidovic ◽  
D. Punos ◽  
M. Tadic
Keyword(s):  
Litter Size ◽  
Selection Criteria ◽  
Genetic Correlations ◽  
Heritability Estimates

The analysis of estrus symptoms has been done on 656 purebred and 884 crossbred gilts. Heritability estimates for estrus reaction in purebreds were low, 0.12 and 0.14 for crossbreds. The heritability for number of ovulation egs in purebred and crossbreds were 0.40. Genetic correlations between estrus reaction and litter size in first litter were high:0.88 than estrus reaction and life production 0.76. Correlation between same traits for crossbreds were higher: 0.93 and 0.87. In carantin room we measured age and weight of gilts together with estrus. The first estrus showed 90.8% and second 90.2% in purebred and 94.7% and 93.8% at F1 gilts. The gilts which did not show regular first and second estrus get born between 2 and 9, average 6.23 for purebred and 7.11 F1 alive piglets. Later on they had longer interval between birth and next estrus, 17- 48, average 32 empty days for purebred and 28 crossbreds gilts. Those animals had significant lover life production. In conclusion, it is necessary to note estrus reaction in carantin room at the beginning of production life of gilts. Gilts with irregular oestrus is necessary to get out of production imediately from carantin room to decrease economical losess in production.

scholarly journals Evaluasi Produktivitas Domba Ekor Gemuk Berdasar Reproductive Rate

2018 ◽  
Vol 20 (2) ◽  
pp. 64
Author(s):  
Sigit Prastowo
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Reproductive Rate ◽  
Ovulation Rate ◽  
Variable Component

<p>Fat Tailed Sheep represent one of Indonesian livestock that having excellence of comparability with other ruminants livestock. The excellence is quickly adult, short of pregnant age, and has the nature of bearing twin, so if evaluated from development aspect will be very beneficial. Reproductive Rate (RR) is a mount of reproduction ability from a group of ewes. Reproductive Rate defined as amount of weaned lamb by ewe every year. Variable/component related to RR are litter size, lamb mortalities before weaning and lambing interval.</p><p>Litter size is general influenced by difference of breeds, age and sufficiency of nutrition. Litter size is peculiarly influenced by ovulation rate that determined by breed, age, nutrition and parity. Lamb age, litter size, birth weight, season, nutrition and parity are influenced lamb mortalities before weaning. Lambing interval determined by nutrition factor and management, which is matting pattern and lamb weaning.</p>

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.

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