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

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.

Vaccination against follistatin and the effect on ovulation rate in estrus-induced gilts

2003 ◽  
Vol 83 (3) ◽  
pp. 487-492
Author(s):  
C. R. Christensen ◽  
M. J. Redmond ◽  
B. Laarveld
Keyword(s):  
Treatment Group ◽  
Key Words ◽  
Luteal Phase ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Significant Difference ◽  
Ovarian Morphology ◽  
Antibody Titers

Primiparous sows were vaccinated against follistatin to determine the effect on ovulation rate following typical commercial estrus induction and synchronization. Seventy-five gilts received four vaccinations against a recombinant porcine follistatin (FS) or a sham vaccine (CTL). At 85 kg, gilts were induced into estrus with a combination of PG600 and hCG and synchronized using PGF2α. At the second estrus, antibody titers ranged from 0 to1:6400 in the FS-vaccinated treatment group and no FS antibodies were detected in the CTL group. Late in the second subsequent luteal phase the reproductive tracts of the gilts that had displayed two estruses were collected. There was no significant difference in the number of corpora lutea (FS = 13.2 ± 0.5, CTL = 14.5 ± 0.7) or corpora albicantia (FS = 12.1 ± 1.9, CTL = 12.3 ± 2.0) between treatments. Follistatin-vaccinated gilts displayed an increased number of luteal structures which resembled corpora hemorrhagica (P = 0.04). This study shows that vaccination of gilts against FS concurrent with estrus induction and synchronization affected ovarian morphology, although an effect on ovulation rate was not apparent. Key words: Swine, follistatin, immunoneutralization, fecundity, ovulation rate

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

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.

REPEATABILITY OF OVULATION RATE, NUMBER OF LAMBS BORN AND OVA LOSS IN SHEEP WITH DIFFERENT OVULATION RATES

1989 ◽  
Vol 69 (2) ◽  
pp. 307-314 ◽  
Author(s):  
M. H. FAHMY
Keyword(s):  
Key Words ◽  
Litter Size ◽  
First Record ◽  
Linear Increase ◽  
Genetic Group ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Genetic Groups ◽  
Quadratic Relationship

Ovulation and lambing records of 214 ewes from nine genetic groups varying in ovulation rate (OR) from 1.8 to 3.2 corpora lutea (CL) and number of lambs born (LB) from 1.2 to 2.1 were analyzed to study the relation between OR, LB, ova loss (OL) and their repeatabilities. The nine genetic groups were DLS, Finnsheep (F) and seven crosses from these two breeds ranging from 1/8 to 7/8 Finnsheep breeding. Intrayear repeatability of OR averaged 0.59 for all genetic groups combined. It ranged from −0.20 for DLS to 0.93 for 5/8 F. Interyear repeatability averaged 0.38 and ranged from 0 for DLS to 0.54 for 3/8 F. OR showed a linear increase (b = 0.22 ± 0.02) with increase in Finnsheep breeding whereas repeatabilities showed a significant quadratic relationship. Repeatability of OR was more associated with variability than with mean OR. Repeatability of OR for ewes which had 1, 2, 3 or 4 CL at first record and averaged 2.3 ± 0.5,2.5 ± 0.7,3.4 ± 1.0 and 3.4 ± 1.3 CL at the following two records was, −0.09, 0.33, 0.42 and 0.42, respectively. Lambs born increased with the increase in Finnsheep breeding from 1.2 for DLS to 2.1 for Finnsheep. Ova loss averaged 35% and was fairly constant in the different genetic groups. Repeatabilities for LB and OL for each genetic group were generally small and mostly nonsignificantly different from zero. For the genetic groups combined the estimates were 0.15 and 0.14 for LB and OL, respectively. The correlation between OR and LB (0.25) was lower than that between OR and OL (0.58) and LB and EM (−0.62). Key words: Ovulation rate, litter size, ova loss, repeatability, Finnsheep crosses, DLS sheep

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

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.

A note on the effect of level of nutrition after weaning on the resumption of reproductive activity by ewes of two Spanish breeds lambing in spring

1993 ◽  
Vol 56 (2) ◽  
pp. 273-276 ◽  
Author(s):  
J. A. Abecia ◽  
F. Forcada ◽  
L. Zarazaga
Keyword(s):  
Breeding Season ◽  
Reproductive Activity ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Medium Term ◽  
Sheep Breeds ◽  
Mean Time

Two experiments were carried out from April to September 1990 at Zaragoza, Spain. Fifty-three Rasa Aragonesa (RA) ewes, weaned in April, were studied in experiment 1, whilst 33 Salz (Sz) ewes, weaned in June, were studied in experiment 2. From weaning onwards, the animals were allocated to two groups receiving two planes of nutrition: high (H) and low (L). Mean time between weaning and the first detected oestrus was 113 (s.e. 2·7) and 52 (s.e. 3·0) days for RA and Sz ewes, without any significant effect of the plane of nutrition. Ewes of the H group showed a constantly higher ovulation rate than those of the L group with a significant effect of the plane of nutrition in the second fortnight of August (P < 0·05) and of September (P < 0·001) in RA ewes (1·68 v. 1·29 and 1·89 v. 1·38 corpora lutea for H and L groups, respectively) and in September (P < 0·01) in Sz ewes (2·53 v. 2·00 corpora lutea for H and L groups).In conclusion, a slightly higher plane of nutrition after weaning in these sheep breeds, lambing in spring, cannot advance either the reproductive resumption or increase the ovulation rate of the first cycle. The high plane of nutrition after weaning exerts a significant effect on the ovulation rate in the medium term, in the early breeding season.

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