Reproduction in the Female Dasyurid Antechinus-Minimus-Maritimus (Marsupialia, Dasyuridae)

1986 ◽  
Vol 34 (2) ◽  
pp. 189 ◽  
Author(s):  
BA Wilson
Keyword(s):  
Epithelial Cells ◽  
Breeding Season ◽  
Field Data ◽  
Corpora Lutea ◽  
Mark Recapture ◽  
Laboratory Colony ◽  
Pattern Length ◽  
Young Breeding ◽  
Length Of Gestation

Reproduction in female Antechinus minimus maritimus was investigated in the field and laboratory. Field data were obtained from a mark-recapture study. A laboratory colony was maintained to investigate the oestrous pattern, length of gestation and development of pouch young. Breeding occurred in winter with births in July or August. Gestation (mean � SD) was 30.6 � l.5 days for animals mated in the laboratory. Epithelial cells were present in the urine for 34.8 � 8.3 days, a lengthy period compared to A. stuartii (19.3 � 4.4 days). Ovaries from females before the breeding season contained small developing follicles. During the breeding season Graafian follicles (4-8 per ovary) or corpora lutea (4-13 per ovary) were found. Reproduction in A. m. maritimus females is similar to that described previously in other Antechinus.

Reproduction in a laboratory colony of the marsupial mouse Sminthopsis larapinta (Mardupialia : Dasyuridae)

1969 ◽  
Vol 17 (4) ◽  
pp. 637 ◽  
Author(s):  
GK Godfrey
Keyword(s):  
Breeding Season ◽  
Maximum Size ◽  
Urogenital Sinus ◽  
Corpora Lutea ◽  
Young Females ◽  
The Third ◽  
Laboratory Colony ◽  
The Mean ◽  
Mean Cycle ◽  
North Western

A laboratory colony of S. larapinta was established with three females and four males received from north-western Queensland. Over a period of two and a half years 109 young were born and second-generation descendants were produced. In the third breeding season oestrous cycles were irregular and, in the few instances where copulation was recorded, this was associated with almost 100% prenatal mortality. The colony became extinct without the cause being definitely established. In Adelaide S. larapinta had a well-defined breeding season with all females either pregnant or in oestrus from July to February. From March until June all the females were in anoestrus. The males produced sperm throughout the year. A technique was developed for determining the length of the oestrous cycle, based upon the incidence of epithelial cells in the urine. S. larapinta is polyoestrous, with a mean cycle length of 26.25�0.5 days. Gestation occupies 12.5 days, and a maximum of eight young remain in the pouch, attached to the teats, for 40 days. They are suckled in the nest for a further 30 days. Weaning takes place at 70 days, and the young females come into oestrus from 4 months of age onwards. Twenty female reproductive tracts were sectioned and examined and the anatomy and histology described briefly. The mean number of ova shed per ovulation was 30.6 (n = 12) with one instance of 40. The corpora lutea are formed rapidly, and reach their maximum size towards the end of pregnancy. They have completely regressed by the seventh week of lactation. The young are born through a pseudovaginal canal which extends from the median vagina to the urogenital sinus. This closes within 24-48 hr of parturition. The high "pre-pouch" and litter mortality observed during this study is discussed.

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 stage of breeding season or pre-mating oestrogen and progestagen therapy on fertility in ewe lambs

1994 ◽  
Vol 59 (3) ◽  
pp. 429-434 ◽  
Author(s):  
N. F. G. Beck ◽  
M. C. G. Davies
Keyword(s):  
Breeding Season ◽  
Corpora Lutea ◽  
Oestrogen Therapy ◽  
Crown Rump Length ◽  
Ewe Lambs ◽  
Oestradiol Benzoate

AbstractAn investigation was conducted to determine the effect of mating at puberty or third oestrus or after pre-mating oestrogen and progestagen therapy, designed to mimic the changes that occur in plasma oestrogen and progesterone concentrations during the 1st, 2nd or 3rd oestrous cycles, on fertility in ewe lambs. Twenty-five ewe lambs were mated at puberty on mean date of 18 October and 21 were mated at third oestrus on 3 December. Of these, 28% and 81% of animals mated at puberty and third oestrus lambed, respectively (P < 0·05). A similar number of ewe lambs were mated within 24 h of ram introduction in the groups given one, two or three consecutive applications oestrogen and progestagen (25 μg oestradiol benzoate followed 48 h later by a progestagen pessary left in situ for days). Of the 43 corpora lutea, 21 were represented by viable embryos in the 37 animals holding to service after one application compared with 34 out of 46 corpora lutea in 40 animals given three applications (P < 0·05). Furthermore, embryo crown-rump length, embryo weight and amniotic sac width was greater (P < 0·05), on day of pregnancy, in animals given one compared with three applications of oestrogen and progestagen. These results demonstrate that fertility is improved in ewe lambs mated on third oestrus or after progestagen and oestrogen therapy designed to simulate three oestrous cycles.

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.

Development in calves and heifers after hypophysial stalk transection or hypophysectomy.

1977 ◽  
Vol 232 (5) ◽  
pp. E497
Author(s):  
L L Anderson
Keyword(s):  
Epithelial Cells ◽  
Sexual Development ◽  
Follicular Development ◽  
Seminal Vesicles ◽  
Corpora Lutea ◽  
Gonadal Function ◽  
Ovarian Weight ◽  
Thyroid Glands ◽  
Estrous Behavior ◽  
Sexually Mature

Growth was inhibited markedly in prepuberal bull and heifer calves after either hypophysial stalk transection or hypophysectomy as compared with that found in sham-operated calves or in unoperated calves. Male mounting behavior and evidence of puberal estrous behavior were lost or undetected after hypophysial stalk transection or hypophysectomy. Testes regressed, contained few spermatogonia and interstitial cells, and lacked spermatogenesis. Epithelial cells of seminal vesicles, bulbourethral glands, and prostate were cuboidal, indicating inadequate testicular androgen. Atresia of numerous ovarian follicles and reduced ovarian weight occurred in hypophysectomized heifer calves. Graafian follicles regressed after hypophysial stalk transection of sexually mature heifers, but ovaries responded to pregnant mare serum and human chorionic gonadotropin by follicular development, ovulation, and formation of multiple corpora lutea. Thyroid and adrenal gland weights decreased and adrenal cortices atrophied after hypophysectomy, but not after stalk transection. Thyroid glands contained colloid-filled follicles with flattened epithelial cells; atrophy was more extensive after hypophysectomy. Hypophysial stalk transection or hypophysectomy severely depresses growth and arrests sexual development in young calves, but in mature animals exongenous gonadotropins can sustain gonadal function.

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

Reproduction of the Rabbit, Oryctolagus cunniculus (L.), on Macquarie Island, Subantarctic

1978 ◽  
Vol 5 (3) ◽  
pp. 317 ◽  
Author(s):  
IJ Skira
Keyword(s):  
Breeding Season ◽  
Annual Cycle ◽  
First Year ◽  
Corpora Lutea ◽  
Macquarie Island ◽  
Pregnant Females

The reproduction of rabbits on Macquarie I. was studied from December 1973 to February 1975. The breeding season extended from late August 1974 to mid-March 1975; both sexes showed an annual cycle in development and regression of the gonads. Between mid-October and mid-November 92% of females sampled were pregnant; during this period the maximum numbers of corpora lutea and embryos were 8.55 and 6.50 per female respectively. Few resorptions occurred although the number of pregnant females that resorbed increased as the breeding season progressed. Of all rabbit kittens produced in the 1974-75 breeding season, 64% were born by mid-December 1974. Female rabbits in their first year of breeding bore the greatest number of kittens; natality decreased as females aged.

The Ecology of Rattus lutreolus III*. The Rise and Fall of a Commensal Population

1980 ◽  
Vol 7 (2) ◽  
pp. 199 ◽  
Author(s):  
RW Braithwaite
Keyword(s):  
Body Size ◽  
Habitat Use ◽  
Breeding Season ◽  
Sexual Maturity ◽  
Free Living ◽  
Mark Recapture

A free-living population of R. lutreolus living in and around the zoo enclosures of the Sir Colin MacKenzie Fauna Park at Healesville was studied for 27 months by use of mark-recapture trapping techniques. The demography of this population is compared with that of a natural heathland population. The breeding season was 2-3 months longer, growth of juveniles was more rapid, sexual maturity earlier, minimum survival shorter, body size larger, and habitat use less restricted in the commensal population. The evolution of the population and its decline are discussed.

scholarly journals Abundance estimate and seasonal patterns of grey seal (Halichoerus grypus) occurrence in Brittany, France, as assessed by photo-identification and capture–mark–recapture

2007 ◽  
Vol 87 (1) ◽  
pp. 365-372 ◽  
Author(s):  
Maureen Gerondeau ◽  
Christophe Barbraud ◽  
Vincent Ridoux ◽  
Cécile Vincent
Keyword(s):  
Breeding Season ◽  
Site Fidelity ◽  
Seasonal Abundance ◽  
Breeding Period ◽  
Home Ranges ◽  
Grey Seal ◽  
British Isles ◽  
Mark Recapture ◽  
Abundance Estimate ◽  
Photo Identification

It has been suggested that the large grey seal colonies around the British Isles form local populations within a metapopulation, and that seal movements outside the breeding season lead to considerable overlap between individual home ranges. Individual behaviour and population dynamics of small peripheral colonies may also play a role in the metapopulation. We studied the French grey seal colony of the Molène archipelago, at the southern-most limit of the species' range. We analysed photo-identification data with capture–mark–recapture techniques in order to estimate the total seasonal abundance of grey seals in the archipelago and to quantify the seasonal rates of occurrence or movements of male and female seals. We found that between 58 (95% confidence interval: 48–71) and 98 (95% CI: 75–175) individuals hauled out in the archipelago during the summers of 1999 and 2000. The use of multistate models allowed the assessment of seasonal site fidelity and indicated that it varied between key periods of the annual cycle, particularly for females. Males showed a constant fidelity rate of 56% from one season to another. Hence, even though they showed high inter-annual site fidelity, they did not seem to have a preferred season for using the archipelago. On the contrary, female grey seals showed the highest site fidelity between moult and summer (around 80%), and the lowest fidelity between summer and the breeding period (34–43%). Thus, females seem to use the Molène archipelago preferentially in summer and leave the site before the breeding season, which explains the very low local pup production. Philopatry may explain this pre-breeding emigration, and we suggest that most grey seals observed in the Molène archipelago were born and breed in other local breeding populations, probably the south-western British Isles.

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