Journal of reproduction and fertility. Supplement.
Discontinued
Publisher:
Blackwell Scientific Publications for Journals of Reproduction and Fertility,. Cambridge, UK : Journals of Reproduction and Fertility, Ltd.
Frequency: Irregular
Country: England
Language: English
Author(s):
Society for the Study of Fertility.
Start Year:1966 - 2001
Identifiers
| ISSN: | 0449-3087 (Print) 0449-3087 (Linking) |
| NLM ID: | 0225652 |
| (DNLM): | J37020000(s) |
| (OCoLC): | 01639439 |
| Coden: | JRFSAR |
| LCCN: | sn 82004517 |
| Classification: | W1 JO868KA |
Effects of pinealectomy in Pony mares. When mares were pinealectomized in summer or in winter there was no difference in the annual ovulation date of these animals and of pineal-intact controls during the first post-operative breeding season but in the second season the ovulation date of the winter pinealectomized mares was significantly delayed, suggesting a long-term but clear pineal involvement in seasonal reproductive patterns. Exposure of pinealectomized mares to a stimulatory photoperiod failed to advance the average date of first annual ovulation and was similar to that of intact mares receiving no stimulatory lighting. The ...
Effect of number and frequency of inseminations on fertility of mares. Data from 257 normally cyclic mares used in trials over a 10-year period were examined to establish the relationship between the number of inseminations per cycle, duration of oestrus and pregnancy rate. Mares that became pregnant were inseminated more (P less than 0.05) frequently per cycle than mares that did not become pregnant (3.4 versus 2.8). First-cycle pregnancy rates of 22.2, 34.0, 38.6, 52.5, 58.3 and 52.2% were attained when mares were inseminated 1, 2, 3, 4, 5 or 6 or more times per cycle, respectively. The duration of oestrus in mares that became pregnancy was longer (P less than ...
Effects of injected ovarian steroids on reproductive patterns and performance in post-partum mares. Treatment of foaling mares with 150 mg progesterone and 10 mg oestradiol daily beginning within 12 h of parturition resulted in a delay of ovulation (15.6 +/- 2.6 days compared with 10.3 +/- 2.4 days in untreated mares). When mares were mated after this 5.3-day delay there was no advantage in reproductive performance over that of mares mated according to a conventional management system. Gonadotrophin secretion was inhibited during treatment but the following secretory patterns were similar to those of normal oestrous periods.
Antibodies to the zona pellucida in mares. Cross-reactivity tests indicated that the equine zona pellucida shares common antigen(s) with porcine zona. Porcine oocytes were therefore used to test for the presence of zona antibodies in the sera of horses. Serum samples were collected from 65 mares infertile for unexplained causes: 7 mares were strongly positive for antibodies reactive to porcine zona pellucida as determined by an indirect immunofluorescence method. Of these 7 mares, aged 8-23 years, 2 were nulliparous and 5 were multiparous. Zona-covered horse oocytes were treated with sera from 4 mares previously identified as zona posi...
Effect of increased photoperiod on hormone concentrations in thoroughbred stallions. Stallions on two Central Kentucky farms (9/farm) were studied during the 1980 breeding season. On one farm stallions were exposed to an increased photoperiod (16 h light/day) from 1 December 1979; on the second farm the stallions were maintained in an ambient photoperiod. On the basis of matings per conception (total mating/mares in foal) stallions on each farm were assigned to a high fertility (1 . 9-2 . 4 matings per conception, N = 4) or low fertility (2 . 6-5 . 6 matings per conception, N = 5) group. Exposure of stallions to increased photoperiod significantly increased serum concentration...
Breeding behaviour of a stallion at pasture with 20 mares in synchronized oestrus. A 6-year-old stallion was placed in a pasture for 9 days with 20 mares in which oestrus was synchronized with two treatments of PGF-2 alpha given 15 days apart. Breeding and observation began 3 days after the second treatment. Observations were carried out during the daylight hours (05:00 to 21:30 h). Eighteen mares showed oestrus and mated an average of 4.56 times each (range 1-12). There were 1.74 mounts per mating. The maximum number of matings by the stallion during 1 day was 16 on Day 2. The overall mean interval between matings was 72.8 min, ranging from 34.5 min on Day 1 to 128.7 on Day...
A comparison of agents for inducing parturition in mares in the pre-viable and premature periods of gestation. Various regimens of prostaglandins, alone or followed by oxytocin, were given to induce parturition in mares during the pre-viable and premature periods of gestation and in near-term mares. The most successful method of induction was found to be 2 i.m. injections of 500 micrograms fluprostenol (Equimate: I.C.I.) at a 2-h interval followed (if necessary) by 10-20 i.u. oxytocin injected i.v. in 5 i.u. serial increments every 15-20 min. Peak concentrations of the prostaglandin metabolite (PGFM) in response to the inducing agents were shown to be associated with delivery at, but not before, 320 da...
Blood gas and acid–base status in spontaneously delivered, term-induced and induced premature foals. Six spontaneously delivered foals, 8 Thoroughbred foals induced at term with fluprostenol and 17 Pony foals induced prematurely with fluprostenol and oxytocin at a gestational age of 270 to 330 days were studied to determine PO2, PCO2, pH, base excess and HCO3 values in arterial blood between birth and 7 days of age. The Pony foals were subdivided into those that survived greater than 24 h (N = 9) and less than 9 h (N = 8). Blood gas and acid base values in the term-induced foals were similar to those in spontaneously delivered foals. The induced premature foals surviving greater than 24 h had...
Some aspects of equine embryo transfer. The number of successful embryo recoveries was 56.0% in experimental mares with no history of breeding problems but in barren mares only 34.3% of embryo recovery attempts were successful. When a recovery attempt was successful, the incidence of twin embryos was 10.7% in experimental mares and 16.7% in barren mares. Maintenance of embryos in vitro for greater than 6 h before non-surgical transfer significantly reduced pregnancy rates compared to maintenance for less than 3 h. The pregnancy rate in recipients at 100 days after ovulation was lower (P less than 0.05) than those at 24 and 30 days a...
Isolation and identification of steroids from gonadal vein blood of the fetal horse. Direct connection of the artery of a fetal ovary to the carotid artery of the mare allowed collection of a large volume of blood over a 30-min period. Extraction of steroids and their fractionation was followed by separation of the steroids by alumina adsorption chromatography, and Sephadex LH-20 and Celite partition chromatography. Further resolution of the material by HPLC led to the identification of dehydroepiandrosterone (DHA) by nuclear magnetic resonance and mass spectrometry. Other compounds were isolated, which remain to be identified fully, but in the 8th month of pregnancy the princ...
Effects of exogenous steroids on serum FSH and LH, and on follicular development in cyclic mares. Cyclic mares were given daily i.m. injections of 150 mg progesterone (Group P, N = 4), 150 mg progesterone and 10 mg oestradiol-17 beta (Group PE, N = 3), 10 mg oestradiol-17 beta (Group E, N = 3) or cottonseed oil vehicle (Group C, N = 4), from the day after ovulation (Day 1) to Day 28. Blood samples were collected daily, and the ovaries were palpated every 1-2 days. Serum FSH and LH concentrations were measured in all samples, and means determined for 7 consecutive 4-day periods throughout treatment. Comparisons within each steroid treatment group between time periods and comparisons between...
The repeatability of seminal characteristics of stallions. Fifteen seminal characteristics were measured in ejaculates from 4 laboratory stallions and from 164 commercial stud stallions. Complete field and laboratory data were available from 536 and 531 ejaculates, respectively. These were obtained over 4 breeding seasons (1974/75-1977/78) and 9 breeds were represented. Stallions at commercial studs produced 1-13 ejaculates at intervals of approximately 4 weeks and ranging from 1 h to 1 year apart. Intra-class correlations or 'repeatability' of each seminal characteristic were calculated. Significant between-stallion variation occurred in all characte...
Use of ultrasound echography for early diagnosis of single and twin pregnancy in the mare. In 1981 a trial was conducted on 6 Newmarket Thoroughbred stud farms into the use of real-time ultrasound echography (scanning) as an aid to the early diagnosis of pregnancy in the mare. The procedure was found to be practicable and interpretation of the findings was relatively straightforward. Pregnancy was positively diagnosed from as early as 14 days after ovulation and a number of twin pregnancies were recognized, some in which the conceptuses were situated in separate horns of the uterus but an almost equal number in which the conceptuses were together in the same horn. It was concluded t...
Glucocorticoid suppression of oestrus, follicles, LH and ovulation in the mare. Dexamethasone, a synthetic glucocorticoid, was administered (30 mg/day) from Day 10 after ovulation to assess the involvement of the adrenal glands in the ovulatory cycle. Only 1 of 8 mares treated in this way exhibited behavioural oestrus, compared to 7 of 8 control mares. Mean maximum LH concentration and follicle size were significantly reduced. Ovulation occurred in 1 and possibly in 2 other treated mares, compared to all 8 control mares. The results demonstrated that dexamethasone can interfere with ovulation and associated events in the mare, but the mechanism of action is uncertain.
Epidemiological and bacteriological studies of Corynebacterium equi isolates from Californian farms. Soil samples were collected from 6 horse breeding establishments in California and cultured for Corynebacterium equi. Only 3 of the farms had a history of the occurrence of pneumonia caused by C. equi. One farm had experienced an outbreak in 5 out of 6 foals just before soil sampling. Soil isolates were identified as C. equi on the basis of physical and biochemical characteristics found to be consistent with isolates of equine origin. C. equi was found in many soil samples within endemic areas where greatest concentrations were obtained in places accessible to horses. On non-endemic farms, onl...
Characteristics and fertility of stallion semen. A study of stallion fertility was conducted on commercial studs in eastern Australia over 4 breeding seasons (1974/75-1977/78). Data from 47 stallions (66 stallion seasons) aged 2-26 years and representing 7 breeds and 1664 mares were used to relate seminal characteristics to fertility. Percentage pregnancies per service was the most sensitive measure of fertility with stallions on commercial studs. Breed and age of stallion, breeding season and the referral status of the stallion ('suspect' or 'normal') had significant (P less than 0.01) effects on fertility. The semen characteristics that we...
Transmission electron microscopy of horse embryos 3-16 days after ovulation. The 23 embryos were obtained by flushing the reproductive tract. Though the general cytology was observed, most attention was given to the formation of the embryonic capsule. It first appeared as a thin uniform layer on the inner surface of the zona pellucida of embryos recovered from the uterus on Day 6. By Day 8 the capsule was about 1 micron thick and the zona pellucida had been shed. In fixed embryos of 11 days and over the capsule was 3 microns thick and had a finely stippled but otherwise homogeneous appearance.
Patterns of stallion sexual behaviour in the absence of mares. In the first experiment the response of 93 adult stallions to stimulated and natural sexual stimuli was observed just before and 2 weeks after the breeding season (December and July respectively). About 72% of the stallions reacted the same before and after the breeding season (P less than 0.01) while 9% behaved similarly and 19% differently. Also, 72% of the stallions reacted with sexual arousal (mounting) to one of 3 successive simulated sexual stimuli; 25% to a dummy, an additional 44% to a gentle stallion and another 3% to a dummy smeared with mucus and urine from a mare in oestrus. In ano...