scholarly journals MORPHOLOGY AND RESPONSIVENESS OF THE TWO LARGEST OVARIAN FOLLICLES IN ANESTROUS EWES

1977 ◽  
Vol 57 (3) ◽  
pp. 459-464 ◽  
Author(s):  
PIERRE MATTON ◽  
JACQUES BHÉREUR ◽  
J. J. DUFOUR
Keyword(s):  
Breeding Season ◽  
Ovarian Follicles ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
India Ink

The morphology and the responsiveness of ovarian follicles to an ovulating stimulus imposed in the presence or absence of previously induced corpora lutea (CL) were studied in anestrous DLS ewes (Dorset × Leicester × Suffolk). Induction of CL formation was done with 500 IU of PMSG given intravenously. In CL-bearing ewes, the diameter of the largest follicle was significantly larger 12 and 16 days after PMSG injection, while that of the second largest follicle was increased only on day 12. When ovulation was induced with 500 IU PMSG on day 16, the presence of a previously induced CL did not modify the ovulation rate. The two largest follicles identified with India ink markings 4 days prior to PMSG injection did not respond by ovulation and most of these follicles had become completely atretic by day 21 of the experiment. When the two largest follicles, however, were identified and marked on the day of PMSG injection, 65% of them responded to the stimulus. This indicated that turnover of the large follicles was occurring during the anestrous season as is the case during the normal breeding season.

IDENTIFICATION OF OVARIAN FOLLICLES AT ESTRUS AND DEVELOPMENT OF THEIR ENSUING CORPORA LUTEA IN SINGLE AND MULTIPLE OVULATING EWES ON TWO FEEDING REGIMES

1977 ◽  
Vol 57 (4) ◽  
pp. 647-652 ◽  
Author(s):  
J. J. DUFOUR ◽  
P. MATTON
Keyword(s):  
High Energy ◽  
Ovarian Follicles ◽  
Low Energy ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
The Third ◽  
India Ink ◽  
Feeding Regimes

Twelve hours after standing estrus was first detected, 30 ewes had their four largest follicles identified and marked with India ink. Seven days later, ovulation rates and origin of the corpora lutea (CL) from previously marked follicles were determined. Feeding a high energy ration from day 10 to estrus did not change the ovulation rate as compared to feeding a low energy ration. Its only effect was to increase the diameter of the third and fourth largest follicles. The diameter of the largest follicle was identical in single and multiple ovulators. However, in multiple ovulators, the diameter of the second largest follicle was larger than in single ovulators. The largest follicle identified at estrus developed into a CL that was 15% heavier in single than in multiple ovulators. In multiple ovulators, the second largest follicle developed into a CL of weight similar to that from the largest follicle.

A note on attainment of puberty of september-born early-maturing ewe lambs in relation to level of nutrition

1991 ◽  
Vol 53 (3) ◽  
pp. 407-409 ◽  
Author(s):  
F. Forcada ◽  
J. A. Abecia ◽  
L. Zarazaga
Keyword(s):  
Sexual Activity ◽  
Breeding Season ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Ewe Lambs ◽  
Early Maturing ◽  
Age At Puberty

The attainment of puberty in September-born early-maturing ewe lambs was studied at Zaragoza (latitude 41° 40' N). Thirty twin Salz females were allocated to two groups receiving two nutrition levels after 3 months of age: high (500 g/day lucerne hay and 500 g/day concentrate) (H) and low (500 g/ day lucerne hay) (L). Oestrus was detected daily by aproned rams. Corpora lutea were counted after oestrus and plasma progesterone levels monitored each week.In the first breeding season (January to February) the percentage of females showing sexual activity (silent emulation or oestrus and ovulation) was higher in the H compared with the L group (67 and 20%; P < 0/05). Nonpubertal oestrus before the main breeding season was detected in 67% of animals. In the main breeding season and for H and L groups respectively, percentage of females showing silent ovulation before puberty was 67 and 33% and mean age at puberty extended to 319 (s.e. 4-8) and 314 (s.e. 3·7) days. Ovulation rate at puberty was 1·73 (s.e. 0·13) and 1·33 (s.e. 0·15) respectively (P < 0·05).

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.

407 SUPERSTIMULATORY RESPONSE WITH DECREASING DOSES OF FOLLICLE-STIMULATING HORMONE v. A SINGLE DOSE OF FOLLICLE-STIMULATING HORMONE - EQUINE CHORIONIC GONADOTROPIN DURING BREEDING AND NONBREEDING SEASON IN SHEEP

2010 ◽  
Vol 22 (1) ◽  
pp. 360
Author(s):  
M. I. Cueto ◽  
F. Pereyra-Bonnet ◽  
P. Silvestre ◽  
A. E. Gibbons
Keyword(s):  
Single Dose ◽  
Breeding Season ◽  
Recovery Rate ◽  
Follicle Stimulating Hormone ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Nonbreeding Season ◽  
Embryo Recovery ◽  
The One ◽  
Stimulating Hormone

The aim of the study was to assess possible variations in superovulatory yields due to different FSH treatments at 2 times of the year. Superovulation and embryo recovery were performed during the breeding (n = 63) andnonbreeding (n = 46) seasons in Merino ewes located at 41°S latitude. Animals were kept under the same conditions, housed outdoors in a sheltered and covered pen, and were fed a liveweight maintenance ration. All animals received 60-mg medroxyprogesterone acetate intravaginal sponges (Progespon®, Syntex, Buenos Aires, Argentina) for 14 days. Ewes were then randomly assigned to 2 different superovulatory treatments: classic (n = 74) and one shot (n = 35) in both seasons. Classic superovulatory treatment consisted of 7 decreasing doses (2 × 48 mg, 2 × 24 mg, 2 × 20 mg, and1 × 16 mg NIH-FSH-P1)ofFSH (Folltropin®-V, Bioniche, Belleville, Ontario, Canada), administered twice daily from 48 h before to 24 h after pessary removal. A dose of eCG (300 IU; Novormon®, Syntex) was administered at progestagen removal. One shot superovulatory treatment consisted of a single dose of FSH (70 mg NIH-FSH-P1) plus 300 UI of eCG injected at pessary withdrawal. Embryo donors were inseminated by laparoscopy with frozen-thawed semen (100 × 106 spz) 12 h after the onset of estrus. Surgical embryo recovery was done on Day 7 after sponge withdrawal and embryos were graded for quality according to morphology (Grade 1 = excellent or good; Grade 2 = fair; Grade 3 = poor; and Grade 4 = dead or degenerated; IETS 1998). A 2 × 2 factorial ANOVA was used to test the main effects (season and superovulatory treatment) and interactions. There were no significant differences in the proportion of responding ewes (>3 corpora lutea), ovulation rate, and recovered Grades 1 to 2 embryos between the breeding and nonbreeding season (Table 1; P > 0.05). However, number of recovered ova/embryos and ova/embryo recovery rate were higher during the breeding season compared with the nonbreeding season, whereas the percentage of nonfertilized ova was lower in the breeding season than in the nonbreeding season (P < 0.05). Analysis of data comparing superovulatory treatments showed that the proportion of responding ewes, ovulation rate, recovered embryos, and recovered Grades 1 to 2 embryos were lower for the one shot treatment than for the classic treatment (P < 0.05). Embryo recovery rate and nonfertilization rate did not differ between treatments (P > 0.05). It was concluded that there was an increase in the number of total recovered ova/embryos during the breeding season compared with the nonbreeding season, although the number of recovered good-quality embryos was not affected. The use of multiple FSH injections produced a higher number of total recovered and viable embryos in Merino sheep than the one shot superovulatory treatment. Table 1.Embryo yields in ewes submitted to superovulation

THE BREEDING SEASON AND OVULATION RATE OF DLS EWES AS DETERMINED BY LAPAROSCOPY

1986 ◽  
Vol 66 (1) ◽  
pp. 297-301 ◽  
Author(s):  
MOHAMED H. FAHMY ◽  
JACQUES J. DUFOUR
Keyword(s):  
Key Words ◽  
Breeding Season ◽  
Ovulation Rate ◽  
Corpora Lutea

Ovaries of 19 DLS (1/2 Dorset 1/4 Leicester 1/4 Suffolk) ewes were examined by laparoscopy at 16- to 18-day intervals to determine the length of the breeding season. Nine ewes (47%) had corpora lutea (CL) and/or corpora albicantia (CA) between 22 Apr. and 26 May 1983. The average date of the first estrus accompanied by mounting was 28 Aug. ± 10 d in 1983 and 20 Sept. ± 15 d in 1984. The interval between first and last observed CL and first and last mounting averaged 251 ± 28, and 222 ± 32 d, respectively. The average dates in 1984 when mounting ceased and CL and CA were last observed were 11 Apr. ± 26 d, 26 Apr. ± 27 d and 9 May ± 30 d, respectively. The anestrous period averaged 133 ± 28 d. The average ovulation rate at the last two cycles of a season and the first two cycles of the following breeding season were 1.6 ± 0.53 and 1.7 ± 0.65 for the 1983 and 1.1 ± 0.31 and 1.4 ± 0.71 for the 1984 seasons, respectively. Key words: Breeding season, ovulation rate, laparoscopy, DLS sheep

Prepubertal reduction of the ovarian follicle population by combined LH-releasing hormone antagonist treatment and unilateral ovariectomy influences follicle characteristics but not the ovulation rate at first oestrus

1992 ◽  
Vol 135 (3) ◽  
pp. 439-446 ◽  
Author(s):  
W. A. van Cappellen ◽  
E. C. M. van Leeuwen ◽  
P. Kramer ◽  
H. M. A. Meijs-Roelofs
Keyword(s):  
Ovarian Follicle ◽  
Ovarian Follicles ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Normal Range ◽  
Juvenile Period ◽  
Unilateral Ovariectomy ◽  
Releasing Hormone ◽  
Total Pool ◽  
Lh Releasing Hormone

ABSTRACT The effect on first ovulation of the massive reduction of the total pool of ovarian follicles during the infantile and late juvenile period was studied in rats. Treatment with an LH-releasing hormone antagonist (LHRH-A) during infancy (5 mg/kg body weight on days 6, 9, 12 and 15 of life) was combined with unilateral ovariectomy performed on either day 15 (early ULO) or 2–5 days before the expected day of first ovulation (late ULO). Rats were killed on the day of first or second oestrus, when blood was collected and the (remaining) ovaries were prepared for differential counting of follicles and corpora lutea. In addition, blood was sampled 8 h after ULO and the ovaries studied histologically in the group of rats which were unilaterally ovariectomized 2–5 days before first ovulation. The time of first ovulation was not influenced by treatment with LHRH-A, early or late ULO, or a combination of LHRH-A treatment and ULO. Ovulation rate after LHRH-A treatment was decreased, but was still within the normal range in intact rats and in early ULO rats compared with saline-treated controls. Serum FSH concentrations 8 h after ULO performed 2–5 days before first ovulation were similar in saline- and LHRH-A-treated rats (845 ± 59 and 801 ± 99 (s.e.m.) μg/l respectively) and had increased compared with intact controls (216 ± 15 μg/l). Treatment with LHRH-A resulted in a reduction of more than 50% in healthy and atretic follicles, and late ULO reduced the number of healthy follicles even further. In saline-treated rats late ULO decreased the rate of atresia, but in LHRH-A-treated rats atresia was not reduced further by (late or early) ULO. It is concluded that even after massive reduction of the pool of ovarian follicles by early LHRH-A treatment combined with late or early ULO, the timing of the first ovulation was normal and ovulation rates, although somewhat lower in some LHRH-A-treated rats, were within the normal range. Journal of Endocrinology (1992) 135, 439–446

212 EFFECT OF A LOW DOSE OF eCG ON SUPEROVULATION AND EMBRYO COLLECTION IN WOOD BISON DURING THE BREEDING SEASON

2014 ◽  
Vol 26 (1) ◽  
pp. 220
Author(s):  
J. M. Palomino ◽  
R. J. Mapletoft ◽  
M. R. Woodbury ◽  
M. P. Cervantes ◽  
G. P. Adams
Keyword(s):  
Breeding Season ◽  
Low Dose ◽  
Transvaginal Ultrasound ◽  
Animal Health ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Chi Square ◽  
Chi Square Test ◽  
Wood Bison ◽  
Follicular Response

In an effort to conserve a threatened Canadian species, Bison bison athabascae, we developed an embryo collection protocol subsequent to superovulatory treatment involving two doses of FSH diluted in hyaluronan given 48 h apart. The follicular response to superstimulatory treatment was satisfactory, but many follicles did not ovulate, thus limiting the number of embryos collected. Based on recent results in cattle, where replacement of the final doses of FSH with a low dose of eCG resulted in the recovery of a greater number of ova/embryos, the objective of the present study was to evaluate the effect of adding eCG to the superovulatory protocol to increase ovulation rate, embryo collection, and embryo quality in wood bison during the breeding season (September). Ovarian synchronization was induced in wood bison (n = 24) by treatment with a luteolytic dose of prostaglandin (500 mcg, Cloprostenol) followed 8 days later by transvaginal ultrasound-guided follicular ablation. Follicular wave emergence (Day 0) was defined as the day after follicle ablation. Bison were assigned randomly to two groups: FSH (n = 12) and FSH+eCG (n = 12). FSH was diluted in hyaluronan (5 mg mL–1, MAP-5, Bioniche Animal Health, Belleville, ON, Canada) and given intramuscularly on Day 0 (300 mg) and Day 2 (100 mg) in both groups. Bison in the FSH+eCG group received 450 IU eCG (Pregnecol, Bioniche Animal Health) intramuscularly on Day 3, and bison in both groups were administered a luteolytic dose of prostaglandin on Day 3. On Day 5, bison were given 2500 IU hCG (Chorulon, Merck Animal Health, Summit, NJ, USA) intramuscularly to induce ovulation. The bison were artificially inseminated with chilled semen 12 and 24 h after hCG treatment. Nonsurgical embryo collection was performed on Day 13. The ovaries were examined by transrectal ultrasonography on Days 5, 7, and 13 to record the follicular response, ovulation rate, and number of corpora lutea (CL), respectively. Results were compared between groups by t-test or chi-square test (Table 1). The number of ovulatory-sized follicles (≥9 mm), ovulation rate (number ovulations/ovulatory-sized follicles), number of CL, number of ova/embryos, and number of transferable embryos were not different between groups (P = 0.23, P = 0.19, P = 0.25, P = 0.18, P = 0.09, respectively). In conclusion, the superovulatory response and embryo collection rate in wood bison approached that observed in cattle, but were not improved by the addition of a low dose of eCG. Table 1.Response of wood bison (mean ± s.e.m.) to superovulatory treatment with or without eCG

Destinée des deux plus gros follicules des ovaires de brebis à la suite de la destruction du plus gros follicule et/ou de l'enlèvement du corps jaune à deux moments du cycle

1976 ◽  
Vol 54 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Jacques Bhérer ◽  
Jacques DuFour ◽  
Pierre Matton
Keyword(s):  
Inhibitory Effect ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
India Ink

Marking of the largest (F1) and the second largest (F2) follicles of the ovaries of the sheep with India ink has allowed us to observe the fate of these follicles after different treatments.All the F1 and F2 follicles of the controls marked on the 10th day of the cycle became atretic, but when the marking was done on the 14th day, only the F1 (of the marked follicles) ovulated. Destruction of the F1 with or without removal of the corpora lutea allowed some of the F2 to ovulate, whereas only removal of the corpora lutea decreased the number of F1 ovulating. It thus appears that the fate of the F1 is related to the time of the cycle and that the F1 could have an inhibitory effect on the ovulation of the F2. Removal of the corpora lutea also induced the development of several cystic follicles and decreased the total ovulation rate.

A QUANTITATIVE STUDY OF GENETIC DIFFERENCES IN THE INCIDENCE OF OESTRUS, OVULATION AND PLASMA LUTEINIZING HORMONE CONCENTRATION IN THE SHEEP

1973 ◽  
Vol 58 (2) ◽  
pp. 305-317 ◽  
Author(s):  
R. B. LAND ◽  
J. PELLETIER ◽  
J. THIMONIER ◽  
P. MAULÉON
Keyword(s):  
Seasonal Variation ◽  
Luteinizing Hormone ◽  
Breeding Season ◽  
Quantitative Study ◽  
Genetic Differences ◽  
Ovulation Rate ◽  
The Other ◽  
Corpora Lutea ◽  
Hormone Concentration ◽  
Luteinizing Hormone Concentration

SUMMARY Seasonal variation in the ovulation rate and incidence of ovulation was examined in 15 Romanov and 15 Solognote ewes by endoscopy. The ovulation rate of the Romanovs was found to be related to the incidence of ovulation (r = 0·78) and to the incidence of oestrus as measured by daily teasing with aproned entire rams (r = 0·83). The ovulation rate of the Romanovs was greater than that of the Solognotes, and was 2·6 and 1·1 corpora lutea in the two breeds, respectively, in the autumn. The durations of the breeding season and of oestrus of the Romanovs exceeded those of the Solognotes. The characteristics of the preovulatory discharge of luteinizing hormone (LH) and the daily plasma LH levels were studied by radioimmunoassay in the Romanov and Solognote ewes and in ewes of the Berrichon and Berrichon × Romanov breeds. The interval between the onset of oestrus and the discharge of LH was greater in the Romanovs (17·6 h) than in the other breeds (mean = 7·5 h). The total release of LH, however, was not related to the number of corpora lutea formed.

Effect of previous lambing date and subsequent month of mating on reproductive performance in Mule ewes

1999 ◽  
Vol 69 (1) ◽  
pp. 217-222 ◽  
Author(s):  
L. M. Mitchell ◽  
M. E. King ◽  
R. P. Aitken ◽  
J. M. Wallace
Keyword(s):  
Factorial Design ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Fertilization Failure ◽  
Mating Period ◽  
Natural Photoperiod ◽  
Natural Breeding ◽  
Main Factor

AbstractThe objective was to determine the effect of previous lambing date and subsequent month of mating on reproductive performance in Mule (Bluefaced Leicester × Scottish Blackface) ewes. Sixty-four ewes which had previously lambed in January (13 January (s.e. = 1 day)) and 80 ewes which had previously lambed in May (15 May (s.e. = 1 day)) were allocated equally to four mating periods (30 August to 17 September, 1 November to 19 November, 3 January to 21 January and 14 February to 4 March) in a 2 × 4 factorial design. From 20 days before and during their designated mating period, January- and May-lambing ewes were separately housed in straw-bedded pens under natural photoperiod and were given 1 kg per head per day dried grass pellets. A vasectomized ram was continuously present with each group for 17 days and was replaced by a raddled, fertility tested entire Suffolk ram at the start of the mating period. Ewes were mated at a single natural oestrus and those marked by the ram were recorded daily. Ovulation rate was measured by laparoscopy on day 6 after mating. For ewes which had previously lambed in January (16 per group), numbers by month of mating that showed oestrous behaviour, ovulated and were pregnant, respectively, were: September, 16, 15 and 12; November, 16, 15 and 14; January, 15, 15 and 10 and February, 15, 16 and 7. Mean (s.e.) ovulation rates by month of mating were 2·1 (0.16), 2·5 (0.19), 2·1 (0.09) and 2·2 (0.19) corpora lutea per ewe ovulating, and lambing rates by month of mating were 1·3 (0.25), 1·9 (0.25), 1·2 (0.24) and 0·8 (0.23) lambs per ewe to the ram. For ewes which had previously lambed in May (20 per group), numbers by month of mating that showed oestrous behaviour, ovulated and were pregnant, respectively, were: September, 13, 20 and 12; November, 20, 20 and 19; January, 20, 20 and 17 and February, 20, 20 and 13. Mean (s.e.) ovulation rates by month of mating were 2·0 (0.13), 2·3 (0.11), 2·1 (0.05) and 2·2 (0.11) corpora lutea per ewe ovulating, and lambing rates by month of mating were 1·0 (0.21), 2·1 (0.15), 1·5 (0.17) and 1·2 (0.21) lambs per ewe to the ram. Ovulation, pregnancy and lambing rates were not influenced by previous lambing date, but lambing rates were significantly (P < 0·01) reduced for ewes mated in September and February compared with November. Results demonstrate that in Mule ewes acceptable ovulation rates can be achieved throughout the period September to February but lambing rates are reduced when ewes are mated at the extremes of their natural breeding season. The main factor contributing to the reduction in lambing rates was an increase in the number of ewes failing to establish pregnancy as a consequence of ovulation without oestrous behaviour, fertilization failure and (or) total embryo loss.

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