Ovarian response, ova recovery and fertility in merino ewes superovulated either during the luteal phase of their oestrous cycle or after intravaginal progestagen treatment

Five groups of merino ewes were treated with 1000 i.u. of pregnant mare serum gonadotropin (PMSG) as a single injection per ewe. Three of these groups received treatment on days 7,9 and 11 of their oestrous cycle. Oestrus was synchronized with 125 mg of prostaglandin F2α (PG) given two days after PMSG. Oestrus in the other two groups was synchronized by intravaginal progesterone sponges inserted for 14 days. In one group, the sponges were inserted nine days after oestrus onset. In the other group the stage of the oestrous cycle was unknown. In both these groups, PMSG was given a day prior to sponge removal. No significant differences were recorded for either the mean numbers of corpora lutea, unovulated follicles or ova recovery between the five groups. However, progestagen synchronized ewes yielded significantly more fertilized ova (p < 0.05) than PG synchronized ewes

Effect of the method of estrus synchronization and PMSG dosage on estrus and twinning in Ethiopian Menz sheep

Examines the effect of two dosages of PMSG on the onset of estrus and twinning in an African breed of sheep whose estrus was synchronized using either intravaginal progestogen sponge or prostaglandin F2 alph. Table 1 summarises the results of the study. Most ewes (>75 percent) manifested estrus within 72 hours of either sponge removal or the second PGF2 alpha injection. The time to estrus was significantly (P=0.025) shorter in prostaglandin than in progestogen-synchronised ewes, but there was no difference within the synchronisation groups. A few ewes (2 to 4) per group did not conceive to the synchronised estrus, and returned to service, but there was no difference between groups. Twinning and, therefore, the total number of lambs born increased with the PMSG dosage but did not reach overall significant levels between groups

Limitations of intrauterine balloon catheters for ova collection in sheep

Attempts were made to collect ova from superovulated ewes by surgically fitting a balloon catheter in each uterine lumen either during the luteal phase or follicular phase of their oestrous cycle. A total of six ovulations and 37 unovulated follicles were observed and one unfertilized, degenerating ovum was collected from the six catheterised ewes. This was significantly different (P < 0.01) from the 22 ovulations and eight unovulated follicles observed and the 14 ova recovered from the three control ewes. The presence of catheters prevented plasma LH peak during the oestrus following catheterisation, and as a result, ovulation failed as evidenced by the low plasma progesterone levels from that oestrus throughout the experiment. No pathogenic micro-organisms were isolated from the uteri of any of the ewes. However, histological studies showed infiltration of lymphocytes and monocytes in the endometrium of the catheterised ewes but not in the controls, indicating an immunological type of reaction to the presence of the catheters

Peripubertal plasma progesterone patterns in Ethiopian Menze ewe lambs

Plasma progesterone concentrations were determined every 10 days for 38 grazing Menz ewe lambs from weaning until conception. Lambs were either fed extra supplementry concentrates and/or drenched for endoparasites. Inadequate nutrition delayed puberty onset by 4 to 5 months. Progesterone concentrations, determined by the ELISA technique, were basal before puberty. Subsequently, 63 percent lambs exhibited a `silent ovulation' prior to first behavioural oestrus but, transient rises of progesterone were not observed in 45 percent of lambs conceiving at first mating. Further, first oestrous was unovulatory (non-pubertal) in 21.1 percent of animals which may bias estimates of puberty onset based only on first oestrous behaviour. 5 percent of lambs exhibited a gestational oestrous

A retrospective study on some reproductive parameters of German shepherd bitches in Kenya : research communication

Data relating to reproductive parameters of German shepherd bitches were collected from registered German shepherd dog (GSD) breeders with information kept over a 15-year period (1982-1997). The information obtained was verified using the East African Kennel Club records. A total of 594 bitches from 280 breeders were recorded. From these, 798 heats were observed, 594 of which were used for breeding, resulting in 3592 puppies. The mean age at puberty was 519.0 ± 41 days. Heats occurred throughout the year, although significantly (P < 0.05) higher and lower incidences were observed in October and April respectively. Pregnancy significantly (P < 0.01) increased interoestrous interval, which was 247.8 ± 99.6 and 183 ± 52 days among bred/pregnant and non-bred bitches respectively. Most bitches in oestrus (73.7 %) were bred, and breeding was carried out throughout the year, with a distribution closely related to that of heat incidence. Subsequently, whelping occurred throughout the year, and 95.5 %of the bitches that were mated whelped. A mean gestation period of 60.6 ± 5.1 days was observed. The mean litter size was 6.4 ± 0.4 puppies, and did not differ significantly between months. The preweaning losses were low, with 2.3 % stillbirths, 0.9 % culls and 11.4 % mortalities

An epidemiological survey demonstrating decline in reproductive efficiency with age and non-seasonality of reproductive parameters in German shepherd bitches in Kenya

An epidemiological survey undertaken in Kenya indicated that 2 previously well-established factors, namely decline in reproductive efficiency with age, and non-seasonality of canine reproductive parameters, hold true for German shepherd (GSD) bitches in Kenya. Data collection formswere distributed to randomly selected GSDbreeders and information so obtained was verified using East African Kennel Club records. Whelping was recorded throughout the year. The litter size varied from 1 to 14 pups per litter with a mean of 6.3 ±0.4 SD puppies. Records of 567 whelpings and 3592 puppies were studied. The mean monthly whelping rate was 47.3 ±7.2. There was no significant difference in the mean litter size by month (P < 0.05)

The effects of endoparasites on the reproductive performance of on-farm sheep in the Ethiopian highlands

In 1988 and 1989, the effects of endoparasites on reproductive performance of on-farm sheep were studied at 5 sites in the Ethiopian highlands using nematode eggs per gram (EPG) counts, treamatode EPG and packed-cell volume (PCV). Mean litter size, lambing interval, annual reproductive rate and abortion rate were 1.04 to 1.33, 216 to 263 days, 1.7 to 2.1 and 1.3 to 6.5 percent, respectively, in different sites. Although, lambing interval and endoparasitism were significantly different at different sites, there was no significant differences in the level of endoparasitism affected body weights and body conditions scores of breeding ewes. Nursing ewes had more nematode and trematode EPG, low body weight and low body condition score compared with ewes during pregnancy and at lambing. This lactation-rise in EPG could be attributed to stress of suckling which reduced resistance.# percen

Studies on the reproductive performance of Ethiopian sheep by means of an Enzyme Immunoassay Technique; a review

Reviews aspects of several studies on the reproductive performance of Ethiopian Menz sheep in which plasma progesterone concentrations were monitored. The radioimmunoassay (RTA) technique has been used for determining progesterone concentration in blood and milk (Pope et al 1976; Holdsworth 1980), but it requires the use of radioisotopes, expensive equipment and special arrangements for the disposal of waste. In contrast, the enzyme-linked immunosorbent assay (ELISA) is equally accurate, safer and uses less costly equipment. Moreover, commercial ELISA kits are available and some of these can be used qualitatively, making the procedure suitable for field application in the tropics. Table 1 gives summaries of the effect of nutrition and treatment for endoporasites on the trait. Altogether, 50 oestrus period were either detected by rams or confirmed from progesterone profiles