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.

The survival of embryos transferred in large groups to sheep of breeds with different ovulation rates

1977 ◽  
Vol 24 (2) ◽  
pp. 183-187 ◽  
Author(s):  
R. B. Land ◽  
I. Wilmut
Keyword(s):  
Survival Rate ◽  
Litter Size ◽  
Ovulation Rate ◽  
Embryo Survival ◽  
Large Numbers ◽  
Natural Mating ◽  
Large Groups ◽  
Black Faces

SUMMARYThe possibility that embryo survival in a breed of sheep may be related to the number of embryos normally present after natural mating was investigated by transferring large numbers of embryos to sheep of breeds with an approximately two-fold difference in ovulation rate. When the same number of embryos (14) was transferred to each of 12 Scottish Blackface and 11 Finnish Landrace ewes survival was greater in the Finn ewes (10%) than in the Black-faces (4%). The survival of 28% of embryos when transferred in groups of 7 to each of 14 Scottish Blackface ewes indicated that survival was not similar in the two breeds when the number of embryos present was a similar multiple of their natural ovulation rates. When the number of embryos transferred to Scottish Black-face ewes increased from 7 to 14 the decline in survival rate was so great that the number of lambs born also declined, indicating an intermediate optimum ovulation rate for maximum litter size.

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.

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.

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.

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).

scholarly journals SOME ASPECTS OF REPRODUCTIVE EFFICIENCY IN AWASSI EWES: A REVIEW

2021 ◽  
Vol 52 (1) ◽  
pp. 20-27
Author(s):  
Jalal E. Alkass ◽  
Hani N. Hermiz ◽  
Mevan Ibrahim Baper
Keyword(s):  
Genetic Variation ◽  
Survival Rate ◽  
Litter Size ◽  
Management Practices ◽  
Review Article ◽  
Reproductive Capacity ◽  
Reproductive Efficiency ◽  
Overall Efficiency ◽  
Heritability Estimates

Reproductive efficiency in terms of fertility, Prolificacy and survival rate are considered the major components of overall efficiency in sheep productivity. While fertility of Awassi ewes is moderate to high depending on feeding and management practices, however, litter size is low and Awassi is not considered a prolific breed. Heritability estimates of these traits are rather low, and reflect small genetic variation in these traits. The possible avenues for increasing reproductive capacity environmentally and genetically are discussed in the text of this review article.

scholarly journals Performance of Booroola Merino and Finnsheep crossbred lambs and ewes

1988 ◽  
Vol 60 (6) ◽  
pp. 492-499 ◽  
Author(s):  
L. D. Young ◽  
G. E. Dickerson
Keyword(s):  
Birth Weight ◽  
Survival Rate ◽  
Breeding Season ◽  
Litter Size ◽  
Conception Rate ◽  
Embryo Survival ◽  
Ewe Lambs ◽  
Significant Difference ◽  
Kidney Fat ◽  
The Difference

Booroola Merino (B, n= 18) and Finnsheep (F, n =31) rams were mated to F ewes and C3 ewes (1/2 Columbia, 1/4 Suffolk, 1/4 Hampshire). Progeny of these matings were evaluated for performance traits including ewe reproduction through 3 years of age. Averaged over dam breeds, there was no significant difference between B and F sires for conception rate (CR), litter size (LS) at birth or weaning or for lamb mortality to weaning. The difference among sire breeds was not large or significant for birth weight but F sired lambs were significantly heavier than B sired lambs at 63 and 147 days of age. Relative to F sired lambs, B sired lambs had a higher dressing percentage and less fat at the 12th rib but equal estimated percentage kidney fat. A significantly smaller percentage of B-C3 than F, F-C3 or B-F ewe lambs reached puberty by the end of their first breeding season. Ovulation rate at first mating was higher but embryo survival rate tended to be lower for B sired ewes than for F sired ewes. At 2 years of age, B sired ewes produced about 1 kg more wool than F sired ewes. With the exception of the very poor CR of B-C3 ewes at first parity, the differences between the four ewe genotypes were not large or significant for CR at first, second and third parity. The difference between B and F sired ewes in LS at birth was not significant at first parity but B sired ewes were more prolific at second and third parities. However, differences in lamb mortality reduced, and in some cases removed, the differences in LS by weaning time. Relative use of these breeds in commercial U.S. production schemes is discussed.

scholarly journals Effects of flush feeding strategy before breeding on reproductive performance of modern replacement gilts: impacts on ovulation rate and litter traits

2020 ◽  
Vol 98 (6) ◽  
Author(s):  
André L Mallmann ◽  
Lidia S Arend ◽  
Gabriela S Oliveira ◽  
Ana P G Mellagi ◽  
Rafael R Ulguim ◽  
...  
Keyword(s):  
Litter Size ◽  
Reproductive Performance ◽  
Feeding Strategy ◽  
Early Embryo ◽  
Ovulation Rate ◽  
Breeding Cycle ◽  
Corpora Lutea ◽  
Embryo Survival ◽  
Estrous Cycles ◽  
Litter Traits

Abstract AbstractThe effects of two feed levels offered during two estrous cycles before insemination were evaluated on the reproductive performance of gilts. A total of 93 gilts (PIC Hendersonville, TN) were individually housed and manually fed twice a day with 2.1 or 3.6 kg/d of a corn and soybean meal-based diet (3.15 Mcal ME/kg and 0.64% standardized ileal digestible lysine), during two estrous cycles before breeding (cycle 1, between first and second estrus; cycle 2, between second and third estrus). Gilts were weighed at the beginning of the experiment, at second and third estrus, and at slaughter (30.2 ± 1.2 d of gestation). Follicles were counted at second estrus, and the embryo-placental units and the corpora lutea were individually counted, measured, and weighed at slaughter. Gilts fed 3.6 kg/d had greater BW gain during cycle 1 and cycle 2 (P &lt; 0.001; + 9.8 kg and + 10.0 kg, respectively) becoming heavier at second and third estrus (P &lt; 0.001). At second estrus, gilts fed 3.6 kg/d had 1.6 more medium-large follicles (P = 0.074) but no difference in follicle size (P = 0.530) was observed. Gilts fed 3.6 kg/d in cycle 1 or cycle 2 had a greater ovulation rate at third estrus (P &lt; 0.016) than those receiving 2.1 kg/d. Also, 3.6 kg/d in cycle 2 increased early embryo mortality (P = 0.006; 2.3 vs. 1.1 dead embryos) and consequently reduced total embryo survival (P = 0.002; 84.6 vs. 90.1%). Gilts fed 3.6 kg/d during cycle 1 had two more total embryos (P &lt; 0.001; 17.2 vs. 15.1) and two more vital embryos on day 30 (P &lt; 0.001; 16.7 vs. 14.5) in comparison with gilts fed 2.1 kg/d. The coefficient of variation for placental length was greater for gilts fed 3.6 kg/d during cycle 1 (P = 0.003). No further significant effects of feeding levels were observed on embryo and placental traits (P ≥ 0.063). These results suggest that the feeding level during the first cycle after pubertal estrus is crucial to set ovulation rate and potential litter size for breeding at next estrus. However, flush feeding gilts before insemination can negatively impact litter size by reducing embryo survival when breeding at third estrus.

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