A note on the reproductive performance of greyface ewes in moderately fat and very fat condition at mating

1984 ◽  
Vol 38 (2) ◽  
pp. 305-307 ◽  
Author(s):  
S. M. Rhind ◽  
R. G. Gunn ◽  
J. M. Doney ◽  
I. D. Leslie
Keyword(s):  
Reproductive Performance ◽  
Survival Rates ◽  
Ovulation Rate ◽  
Embryo Survival ◽  
Expected Time ◽  
Lambing Rate

ABSTRACTOestrous activity, ovulation rates and embryo survival rates were investigated in Border Leicester × Scottish Blackface (Greyface) ewes with condition scores of approximately 2·75 (moderately fat) or 3·5 (very fat) at mating. Four of a group of 20 very fat ewes failed to show oestrus at the expected time. Very fat ewes had a higher mean ovulation rate (3·36 v. 2·33; P < 0·05) but a slightly lower potential lambing rate (1·10 v. 1·42 lambs born per ewe put to ram) than the moderately fatewes.

Effect of restricted food intake, before and/or after mating, on the reproductive performance of Greyface ewes

1989 ◽  
Vol 48 (1) ◽  
pp. 149-155 ◽  
Author(s):  
S. M. Rhind ◽  
W. A. C. McKelvey ◽  
S. McMillen ◽  
R. G. Gunn ◽  
D. A. Eiston
Keyword(s):  
Food Intake ◽  
Reproductive Performance ◽  
Live Weight ◽  
Experimental Period ◽  
Metabolizable Energy ◽  
Ovulation Rate ◽  
Daily Ration ◽  
The Mean ◽  
Low Levels ◽  
Lambing Rate

ABSTRACTThe effect on the reproductive performance of Greyface (Border Leicester × Scottish Blackface) ewes of a low level food intake and associated loss of live weight from either 14 days before mating, or from the time of mating, until 11 to 26 days after mating, was investigated. Ewes (252) were allocated to one of three treatments with ewes within each treatment divided into two flocks (flock A: 16 ewes per treatment; flock B: 68 ewes per treatment). Ewes of treatment LL were given a ration providing proportionately 0·5 estimated metabolizable energy (ME) requirements for maintenance from 2 weeks before mating. Those of treatment HL were given a daily ration providing 1·5 estimated ME requirements for maintenance until mating and the restricted ration thereafter. Ewes of treatment HH were given the higher ration throughout the experimental period. Flock A ewes were slaughtered at 11 days post mating and flock B ewes at between 18 and 26 days post mating. Treatment differences in the ovulation rates of flock A ewes were not statistically significant but in flock B, ewes of treatment LL had a lower mean ovulation rate (1·81) than those of treatments HL (2·23) and HH (2·09) (P < 0·001). The lower ovulation rate of LL ewes relative to HL ewes in flock B was reflected in a lower mean potential lambing rate per ewe pregnant than in the HL treatment (1·58 v. 1·79; P < 0·01) and per ewe put to the ram (1·37 v. 1·65; P < 0·01). HL ewes had a slightly lower mean potential lambing rate per ewe pregnant (1·79 v. 1·97; P < 01) and per ewe put to the ram (1·65 v. 1·82; P < 0·05) than HH ewes. Ova wastage rates of LL + HL and HH ewes were 0·26 and 014 (P < 001) respectively at 24 days post mating. Values for LL and HL ewes (0·27 and 0·25 respectively) were not significantly different.Estimated mean conceptus lengths were 370, 500 and 1400 μin for LL, HL and HH ewes respectively (P < 0·05).It is concluded that low food intake before mating reduced the mean ovulation rate and low intakes after mating compromised embryo growth rate and induced a higher rate of ova wastage; this increase in the incidence of ova wastage was not significantly exacerbated by the low levels of intake prior to mating.

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.

Effects of post-weaning stress and feeding management on return to oestrus and reproductive traits during early pregnancy in swine

1976 ◽  
Vol 23 (1) ◽  
pp. 103-110 ◽  
Author(s):  
M. H. Fahmy ◽  
J. J. Dufour
Keyword(s):  
Survival Rates ◽  
Reproductive Traits ◽  
Ovulation Rate ◽  
Embryo Survival ◽  
Feeding Management ◽  
Weaning Stress ◽  
Feeding Regimes ◽  
Ad Libitum ◽  
Breed Crosses ◽  
Interval Weight

SUMMARYA total of 177 sows representing five two-breed crosses were used in a 2×2 factorial experiment to study the effects of post-weaning stress (changing environment and group housing) and feeding regime (flushing by feeding ad libitum until mating) on the weaning-oestrus interval and other reproductive traits up to 30 days of pregnancy.The group which was stressed had about 10% (P<0·05) fewer reproductive failures than those not stressed, while little difference was found between the two feeding regimes. About 61% of the flushed sows returned to oestrus within 7 days after weaning, 9% higher than for those not flushed. The stress treatment had little effect on the weaning-oestrus interval. Neither treatment affected ovarian and follicular-fluid weights, percentage of follicles of different sizes, ovulation rate nor number of viable embryos. The flushed group, however, had 9% lower embryo survival than the group not flushed. A positive relation was found between the number of days on ad libitum feeding and ovulation rate and embryonic mortality.Differences among breeds were significant for all the traits, except weaning-oestrus interval, weight of follicular fluids, percentage of large follicles, ovulation and survival rates. The weaning-oestrus interval was not significantly correlated with any of the reproductive traits studied.

Reproductive performance and milk production of the improved Awassi breed as compared with its crosses with the Booroola Merino

1995 ◽  
Vol 60 (1) ◽  
pp. 109-115 ◽  
Author(s):  
E. Gootwine ◽  
A. Bor ◽  
R. Braw-Tal ◽  
A. Zenou
Keyword(s):  
Milk Production ◽  
Survival Rates ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Embryo Survival ◽  
Average Birth Weight ◽  
Significant Difference ◽  
Per Se ◽  
Lamb Survival ◽  
Awassi Breed

AbstractOvulation rate, embryo survival, lamb production, lamb survival and milk production of Awassi and BooroolaAwassi crossbred ewes, kept indoors, were compared. Awassi were non-carriers while Booroola × Awassi (F1) and about half of 3/4 Awassi-1/4 Booroola (BQ) ewes were heterozygous at the FecB gene. Mean ovulation rate increased by 1·5 to 1·6 corpora lutea per ewe ovulating and prolificacy by 0·7 lambs born per ewe lambing in Fj and BC1 (B+) ewes as compared with Awassi. Embryo survival rates in BC1 ewes with two, three and four ovulations were 0·83, 0·68 and 0·71, respectively. Lamb survival rates at 1 day of age were 0·93, 0·90 and 0·77 and average birth weight was 4·9, 4·0 and 3·0 kg for lambs born as singles, twins and triplets, respectively. Average milk production of the Awassi was 506 I per ewe per lactation. F1 and BC1 ewes produced respectively, proportionately 0·48 and 0·63 of the Awassi milk production and there was no significant difference in milk production between BC1,(B+) and BC1(++) ewes. The relatively low milk production of the Booroola Awassi crosses suggests that heterosis and recombination effects on milk production were negative. It is concluded that incorporation of the B allele per se can increase lamb production in the Awassi without affecting its milk production.

scholarly journals The effect of reproductive loss on the performance of a research flock

2020 ◽  
Vol 98 (3) ◽  
Author(s):  
Paul R Shorten ◽  
Sara J Edwards ◽  
Jenny L Juengel
Keyword(s):  
Reproductive Performance ◽  
Ovulation Rate ◽  
Relative Importance ◽  
Sheep Flock ◽  
Embryo Survival ◽  
Reproductive Loss ◽  
Selection For ◽  
Lamb Survival ◽  
And Performance

Abstract The reproductive performance of a sheep flock is dependent on a multitude of complex interacting factors. Achieving optimal flock performance requires knowledge of the reproductive steps and how these are linked and related to available measurements of the state and performance of the flock. The goal was to use previously collected data from a research flock that had undergone selection for fecundity (11,369 lambing records), to model the key reproductive steps affecting flock reproductive performance. The model was used to investigate how changes in liveweight, age, ovulation rate, number of fetuses at midpregnancy, number of lambs born, and birthweight affect the number of lambs weaned and the weaning weight of each lamb in this flock. The data available from the research flock were used to parameterize models of each reproductive step and assess the role of ewe age and premating liveweight on each reproductive step. These models were then linked together as a simulation tool to assess the role of different parameters on flock reproductive performance, which was defined as the total weight of lambs weaned per ewe exposed to the ram. Flock elasticities were calculated that characterize the relative importance of the effect of average premating ewe liveweight (0.81), average ovulation rate (0.33), variance in ovulation rate (−0.095), embryo survival (0.72), lamb survival (1.03), conception failure (0.35), and average ewe age (0.056) on the total kilograms of lamb liveweight at weaning per ewe exposed to the ram. The largest elasticity for lamb survival indicated that a 1% increase in lamb survival is expected to have a 1.03% increase in the total kilograms of lamb liveweight at weaning per ewe exposed to the ram in this flock. Assuming similar costs, interventions to increase lamb survival for this flock will provide the largest increase in the total kilograms of lamb liveweight at weaning per ewe exposed to the ram, which is a key metric of flock performance.

The effect of protein restriction during the rearing period and age on reproductive function in the gilt

1998 ◽  
Vol 1998 ◽  
pp. 155-155
Author(s):  
VL Glasgow ◽  
SA Edwards ◽  
TG McEvoy ◽  
M Shanks
Keyword(s):  
Body Composition ◽  
Reproductive Performance ◽  
Present Experiment ◽  
Protein Quality ◽  
Reproductive Function ◽  
Early Embryo ◽  
Protein Restriction ◽  
Ovulation Rate ◽  
Embryo Survival ◽  
Early Embryo Development

Reproductive performance of gilts/sows can be influenced by metabolic state at crucial points in the reproductive cycle and indeed at a crucial age. It has generally been found that moderate to severe protein restriction has no effect on litter size or embryo survival at day 28 (Pharazyn et al, 1991) when given to gilts over the gestation period. However protein quality and quantity can affect reproductive performance in gilts when imposed over the prepubertal period as indicated previously by lower ovulation rate at an induced puberty and poorer expression of a second oestrus (Cia et al, 1996). In the present experiment the effects of two diets differing in lysine:energy ratio on body composition and subsequent oestrus response, ovulation rate and early embryo development in gilts of two different ages were studied.

Melatonin Treatment of Donor and Recipient Ewes in an Embryo Transfer Programme: Effects on Ovulation Rate and Embryo Survival During Normal Seasonal Anoestrus

1994 ◽  
Vol 1994 ◽  
pp. 78-78
Author(s):  
J.J. Robinson ◽  
T.G. McEvoy ◽  
R.P. Aitken ◽  
I. Robertson
Keyword(s):  
Embryo Transfer ◽  
Intrauterine Insemination ◽  
Survival Rates ◽  
Ovulation Rate ◽  
Fertilization Failure ◽  
Melatonin Treatment ◽  
Embryo Survival ◽  
Seasonal Differences ◽  
Uterine Environment ◽  
Expected Values

Conception rates and litter sizes in ewes are often higher during the peak of the breeding season than at the beginning or end. How much of this is due to seasonal differences in ovulation rate (Montgomery et al 1988) and ram fertility (Colas, 1983) is uncertain. Using laparoscopic intrauterine insemination which virtually eliminates fertilization failure, Aitken et al (1990) obtained estimates of embryo survival for Greyface ewes induced to ovulate in mid-June (mid anoestrus) that were 25, 19 and 13% below the expected values for 2, 3 and 4 ovulations respectively. While this implies that embryos transferred to recipient ewes at an induced oestrus during seasonal anoestrus may have sub-optimal survival rates, it does not identify whether the cause lies solely with the embryo or with the uterine environment or with both. The present study employs reciprocal embryo transfer in conjunction with melatonin treatment to identify the influence of seasonality on the inherent viability of the embryos and the ability of the uterine environment to sustain pregnancy.

Effects of body condition and environmental stress on ovulation rate, embryo survival, and associated plasma follicle stimulating hormone, luteinizing hormone, prolactin and progesterone profiles in Scottish Blackface ewes

1984 ◽  
Vol 38 (2) ◽  
pp. 201-209 ◽  
Author(s):  
S. M. Rhind ◽  
J. M. Doney ◽  
R. G. Gunn ◽  
I. D. Leslie
Keyword(s):  
Luteinizing Hormone ◽  
Body Condition ◽  
Follicle Stimulating Hormone ◽  
Survival Rates ◽  
Ovulation Rate ◽  
Embryo Survival ◽  
Luteal Function ◽  
Endocrine Status ◽  
The Difference ◽  
Stimulating Hormone

ABSTRACTIn a 2 × 2 factorial experiment, half of each of two groups of ewes in high (20 ewes) or low body condition (20 ewes) were subjected to procedures designed to simulate normal management and climatic stresses, and the effects of these treatments on ovulation rate, embryo survival and endocrine status were investigated.The mean ovulation rate of ewes in the high condition group was significantly higher than that of ewes in the low condition group (1·8 v. 11) (P < 0·001). Embryo survival rates were unaffected. Neither ovulation rate nor embryo survival were affected by stressful treatments.Circulating follicle stimulating hormone, luteinizing hormone and prolactin levels were recorded in the peri-ovulatory period. Mean circulating follicle stimulating hormone levels were similar in three of the treatment groups but were generally lower in ewes in the low condition/stressed group. This difference was significant in some of the sampling periods. Neither basal levels of luteinizing hormone nor the size of the pre-ovulatory luteinizing hormone surge were significantly affected by level of body condition or stress but the surge began earlier in ewes in the low condition groups. The difference in timing was not, however, related to ovulation rate. Circulating prolactin levels were consistently and often significantly lower in ewes in poor condition (P < 0·05). Levels were not significantly affected by stress.While ovulation rate was affected by body condition, the recorded progesterone profiles during the first 2 weeks after mating suggest that luteal function was not affected by any of the treatments applied.

The effect of age and growth traits on puberty and reproductive performance in the gilt

1988 ◽  
Vol 46 (3) ◽  
pp. 427-436 ◽  
Author(s):  
P. J. Burnett ◽  
N. Walker ◽  
D. J. Kilpatrick
Keyword(s):  
Litter Size ◽  
Reproductive Performance ◽  
Growth Traits ◽  
Block Design ◽  
Survival Rates ◽  
Live Weight ◽  
Significant Trend ◽  
Age And Growth ◽  
Regression Equations ◽  
Embryo Survival

ABSTRACTAn experiment involving 320 gilts was conducted to investigate the effects of age and growth traits on puberty attainment and reproductive performance in gilts given boar stimulation with or without exogenous gonadotropins. Following ad libitum feeding during rearing, groups of gilts were stimulated for puberty at one of four ages, namely 130, 150, 170 or 190 days. Within each age group, gilts were selected to maximize the variation in live weight, relocated, mixed and allocated to two treatments in a randomized-block design: (a) mature boar contact (boars only) and (b) boar contact plus an intramuscular injection of 400 i.u. pregnant mare's serum gonadotropin + 200 i.u. human chorionic gonadotropin (boars + PG600). Gilts were mated at puberty and slaughtered at 35 days post coitum.For the gilts on the boars-only treatment, the interval from stimulation to puberty decreased significantly (P < 0·05) and became less variable with ascending age at stimulation. Increasing live weight at a given age also reduced the interval from stimulation to puberty. Multiple regression equations involving age, live weight and backfat thickness at stimulation and growth rate from birth to stimulation were calculated to obtain a prediction equation for the interval from stimulation to puberty. The effects of age and live weight at mating on ovulation rate, embryo survival and number of live embryos 35 days post coitum were not significant.For the gilts on the boars + PG600 treatment, 92% attained puberty within 6 days of treatment, with a non-significant trend to improve with increasing age. Mating rates were similar to those on the boars-only treatment (90%). Ovulation rates were higher (P < 0·001) but embryo survival rates were lower (P < 0·001) in the boars + PG600 group, resulting in similar litter size at 35 days post coitum in the boars-only and boars + PG600 treatments. There was a non-significant trend for litter size to increase with age in the boars + PG600 treatment. Thirty-eight of the gilts treated with hormones failed to conceive and 53% were found by ovarian morphology at slaughter to be cycling normally with a tendency for this proportion to increase with age.

Sign in / Sign up

Export Citation Format

Share Document