On the Development of the Eminentia Mediana of the Hypophysis in Rana temporaria, Studied in Normal, Hypophysectomized, and Thyroidectomized Tadpoles.

In the Rana temporaria tadpole, the part of the infundibular floor that eventually becomes the eminentia mediana is very thin throughout premetamorphosis; the supply of aminergic and neurosecretory nerves is poor, and the area is covered by a few fenestrated capillaries. The organ begins to thicken around mid-prometamorphosis owing to a marked invasion of nerves. At this stage it is also penetrated by capillaries and perivascular space extensions, which together form the neurovascular link structures. These become more pronounced during metamorphic climax, when the eminentia mediana attains the adult appearance. Development of the organ is arrested at the premetamorphic stage after thyroidectomy in the young premetamorphic tadpole. Removal of the adenohypophysial primordium from the embryo of the tailbud stage prevents the vascular—but not the neural—component of the eminentia from developing beyond the premetamorphic stage. By contrast, in the American Rana -species investigated the neural component also fails to develop after hypophysectomy.     

Monoamines in the hypothalamo-hypophyseal system of the mouse with special reference to the ontogenetic aspects

Summary An accumulation of monoamines is found in the adult eminentia mediana and infundibular stem, close to the capillaries of the primary plexus, where they seem to be stored mainly in closely packed delicate varicose fibres, often with swollen endings, droplets. The first traces of monoamines are visible in the embryonic eminentia of fetuses from the last three days of the gestation period, but typical monoamine-containing fibre endings close to the primary plexus capillaries in zona externa are not found until towards the end of the first post-natal week. The adult condition is attained two weeks later. Nearly all cells in the adult pars intermedia show a specific yellowish fluorescence whose intensity shows a wide individual variation. Such fluorescent cells are sometimes present in the intermedia of the new-born. In some but not all adult specimens, a fluorescent varicose fibre system is visible. Fluorescent fibres were first observed in the intermedia of the new-born. Fluorescent fibres are visible in n. arcuatus and n. paraventricularis in the fetus at the 16th day of the gestation period. Nerve cell bodies storing visible amounts of monoamines are found in n. arcuatus, n. periventricularis anterior, and n. premammillaris ventralis of the adult. This amine storing activity is first visible in n. arcuatus of the embryo at the 17th day of the gestation period. The adult condition of these cells is reached during the first postnatal week.     

Morphology and distribution of type II supraependymal cells in the third ventricle of the guinea pig.

The distribution and morphology of phagocytic (Type II) supraependymal cells residing within the third ventricle of the guinea pig were investigated by scanning electron microscopy. Type II supraependymal cells were restricted to nonciliated regions of the ventricle. They were most numerous on the choroid plexus, abundant within the infundibular recess and were present on the ventricular floor in the region of the median eminence. Morphologically, they were characterized by a soma from which pseudopodia-like processes extended to the subjacent ependyma. Type II cells varied in configuration according to their location. Those residing on the choroid plexus typically had irregular somas and possessed processes that generally terminated in finger-like extensions. In contrast, cells on the ventricular floor and within the infundibular recess were stellate and possessed processes that terminated in fan-like cytoplasmic expansion. There were no differences noted in the frequency, distribution or morphology of Type II supraependymal cells in male and female animals. Furthermore, cell frequency did not appear to vary in relation to the estrous cycle. The data suggest that the pleomorphism exhibited by Type II supraependymal cells may reflect adaptations to diverse environmental conditions present within different regions of the third ventricle.     

Supraependymal cells and fibers in the third ventricle of the domestic chicken. A scanning electron microscopic study

Supraependymal cells, fibers and what are presumed to be neuronal bulb-like projections were found in the third ventricle of the domestic chicken with a scanning electron microscope. At least two types of supraependymal cells were found: neuron-like cells and phagocyte-like cells. The former were predominantly seen in the area of the paraventricular organ and infundibular recess. The latter were abundant on the ventricular surface of the median eminence and subfornical organ. Bulb or club-like projections thought to be the dendritic terminals of CSF-contacting neurons were observed in the area of the paraventricular organ and infundibular recess. Similar structures were observed at the preoptic recess as well. The supraependymal neuronal components found in the domestic chicken differed from those of mammals in several respects: 1. the wall of the third ventricle was devoid of supraependymal fibrous plexus except for that of the paraventricular organ; 2. bulb-like projections were abundant in the area of the paraventricular organ; 3. supraependymal neuron-like cells were unipolar or bipolar in appearance. These data underline the dissimilarity of the CSF-contacting neuronal system of birds and mammals.     

Exposure to ram wool stimulates gonadotropin-releasing hormone pulse generator activity in the female goat

In the sheep and goat, exposure of anestrous females to a conspecific male odor enhances reproductive activity. Interestingly, a previous report indicated that male goat hair stimulated pulsatile luteinizing hormone (LH) secretion in the ewe. In the present study, we addressed whether ram wool affects the gonadotropin-releasing hormone (GnRH) pulse generator activity in the female goat. Five ovariectomized (OVX) goats were chronically implanted with recording electrodes in the mediobasal hypothalamus, and manifestations of the GnRH pulse generator were monitored as characteristic increases in multiple-unit activity (MUA volleys). Wool or hair samples were collected from a mature ram, ewe and male goat, and their effects on the MUA volley were examined. The exposure to ram wool induced an MUA volley within 1 min in all five OVX goats, as did the exposure to male goat hair. The ewe wool had no effect on the timing of an MUA volley occurrence. An invariable association of MUA volleys with LH pulses in the peripheral circulation was also confirmed in two OVX goats exposed to ram wool. The present results clearly indicate that exposure to ram wool stimulates pulsatile GnRH/LH release in the female goat. Since exposure to male goat hair enhances pulsatile LH secretion in the ewe, it is likely that very similar, if not identical, molecules are contained in the male-effect pheromone in the sheep and goat.     

The influence of superovulation preparations on the levels of catecholamines in eminentia mediana, the pituitary and pineal gland of the sheep.

The influence of hormonal superovulation preparations of FSH (450 IU) or PMSG (1500 IU), on the levels of catecholamines (dopamine, norepinephrine and epinephrine) was studied in the oestrus period using radioenzymatic methods. The administration of FSH caused a significant increase in the concentrations of norepinephrine (NE) and epinephrine (EPI) in eminentia mediana (EM) of sheep (p<0.001 and p<0.01, respectively). The pituitary gland exhibited an increase in the level of norepinephrine after administration PMSG while no marked changes were recorded for epinephrine and dopamine (DA). The administration of FSH affected the increase in pituitary epinephrine (p<0.01). The hormonal stimulation by FSH resulted in a marked decrease of dopamine (p<0.05) as well as in a significant increase of norepinephrine (p<0.05) and epinephrine (p<0.05) in the epiphysis. The comparison of the effect of hormonal preparations on the changes in catecholamine levels showed that the effect of FSH was observed mostly in eminentia mediana and the pituitary gland while that of PMSG was recorded in the epiphysis.     

Visna Virus Meningoencephalomyelitis in Goats

A progressive paresis was encountered in herds of Swedish goats. The symptoms developed during a period of weeks or months, and were initially often seen as a weakness of the hind limbs before the animals became paralytic. The development and the histopathological lesions of the disease in the GNS and the lungs were similar to those of visna in sheep. In vitro grown choroid plexus cells, prepared from affected goats, showed foci of polykaryocytes. Electron microscopy revealed the presence of particles morphologically similar to those of sheep visna virus (SVV). Goats experimentally infected with the goat visna virus (GVV) developed GNS lesions similar to those of visna in sheep and became seropositive to SVV. The results of complement fixation tests, carried out on sera from 11 goat herds, showed a coincidence between seropositiveness and the occurrence of disease in one and the same herd. Using the ELISA method, an average of 80 % of the goats in 5 herds were found to be seropositive to GVV.     

Comparative aspects of biochemical polymorphism in the blood of Caprinae species and their hybrids

Biochemical variation at 14 blood loci was reviewed, and specific features compared experimentally in sheep Ovis aries, mouflon Ovis musimon, goat Capra hircus, aoudad Ammotragus lervia and in 2 stillborn aoudad × goat hybrids. Variation at 3 loci was also studied in dall sheep Ovis dalli, bighorn sheep Ovis canadensis and rocky mountain goat Oreamnos americanus. Haemoglobin C production in an anaemic Hb AB mouflon and in mouflon × sheep hybrids was examined. Mouflon differ from domestic sheep in that synthesis of both Hb β^AHb β^Bchains is switched off during Hb C production. The mouflon × sheep hybrids switched off one or both chains depending on whether they had inherited sheep or mouflon Hb β chain genes. In general aoudad showed a closer affinity to goats than to sheep.     

The anemia-induced reversible switch from hemoglobin A to hemoglobin C in caprine ruminants: immunochemical evidence that both hemoglobins are found in the same cell

During anemic episodes, goats and certain sheep replace hemoglobin A (HbA = α₂β₂^A) with hemoglobin C (HbC = α₂β₂^C). Rabbit serum directed against either purified sheep HbA or purified sheep HbC was prepared. Both types were used to test whether the two hemoglobins are found in the same cell during switching by an indirect fluorescent antibody assay.Unabsorbed antisheep HbA cross-reacted extensively with goat HbA but to a lesser extent with goat or sheep HbC. Similarly, unabsorbed antisheep HbC reacted with these antigens in the order: Sheep HbC > goat HbC > sheep HbA > goat HbA. Cross-absorption resulted in sera specific either for sheep and goat HbA or for sheep and goat HbC. The specificities were confirmed by indirect fluorescent antibody staining of sheep and goat erythrocytes containing either at least 99% HbA or at least 99% HbC.Smears of erythrocytes from sheep and goats in the process of switching were reacted with one of the absorbed sera then with fluorescein conjugated antirabbit immunoglobulin G. The sum of the fractions stained both by anti-HbA and by anti-HbC exceeded 100% during the switch. Most strikingly when HbA was replacing HbC, nearly all cells stained for HbC while more than half stained for HbA. Thus, the two hemoglobins are found in the same cell during switching.     

Regulation of steroid synthesis and metabolism in isolated binucleate cells of the placenta in sheep and goats.

Binucleate cells of sheep and goat fetal placentae comprise about one-fifth of the trophectodermal layer at the feto-maternal interface. When isolated and incubated in vitro they produce the steroids that are synthesized by the placenta in vivo (progesterone in sheep, 5 beta-pregnane-3 alpha,20 alpha diol in goats). This study demonstrates that progesterone synthesis in binucleate cell preparations in sheep was increased by prostaglandin (PG) E-2, nordihydroguaiaracetic acid (NDGA) and methylisobutylxanthine, but reduced by indomethacin, whereas in goats only NDGA produced any effect (an increase). None of the other compounds tested (luteinizing hormone, follicle stimulating hormone, prolactin, dibutyryl cAMP, A23187 or phorbolmyristic acetate) had any effect. Sheep binucleate cells also produced PGE-2 from arachidonic acid. These results suggest that, in sheep, products of both the cyclooxygenase (producing PGE-2) and lipoxygenase (inhibited by NDGA) pathways of arachidonic acid metabolism have regulatory roles in placental steroid synthesis, but only the lipoxygenase pathway is relevant in goats.     

Preferences for sheep or goats in Indonesia

This paper aims to explore farmers’ preferences for sheep or goats based on feeding practices, animal and flock performances and economic benefits of sheep and goats in different agro-ecological zones in Central Java, Indonesia. In total, 150 smallholder farmers were selected from three agro-ecological zones: the lowlands, the middle zone, and the uplands. Feeding and performance parameters were estimated through weekly farm visits and farm records, from September 2001 to August 2003. In the lowlands, small ruminants were fed mainly with field grass and crop residues, whereas in the middle zone and uplands feeds fed were mainly field grass and leaves. Sheep were given more opportunities to graze than goats, however, grazing was not a major component in the diets. In the lowlands and the middle zone the differences in feed intakes, ADG and reproductive performances between sheep and goats were small. In all zones, does had significantly larger litters than ewes. In the uplands, goats had a significantly higher DMI, grew slightly faster, and had a higher weaning rate than sheep. Consequently, in the uplands, the total economic benefits from goat flocks were 25% higher than from sheep flocks. The major differences in agro-ecological conditions that affect the choice for sheep or goats were the availability of cassava peels in the lowlands, favouring a choice for sheep, and the abundance of leaves in the middle zone and uplands, which favours keeping goats. The promotion of goats by the government, the family tradition of keeping sheep or goats, the preference for sacrificing sheep for religious festivities, and the high initial investment needed to buy goat breeding stock could be other important motives to keep sheep or goats. Sheep fattening based on rice bran supplementation could be a feasible innovation in the lowlands. In the middle zone and uplands goat breeding could make a positive contribution to rural livelihoods.     

Hemoglobin function in the developing goat and sheep

Comparative studies of the blood of newly born goats and sheep have indicated a number of mechanisms which are responsible for a decreasing affinity for molecular oxygen in these developing animals during the first 40 to 60 days after birth.
The concentration of 2,3-DPG in the red cells of young goats increases four to sixfold during the first 3 to 4 days of life, and this increase is associated with a marked decrease in the cellular pH; 2,3-DPG does not bind to hemoglobins of goats and the decreased affinity for oxygen of goat blood at this period is apparently due to the lowered pH produced by the large increase of intracellular anions. Similar changes occur in young lambs.
After 15 to 20 days the changes of the dissociation curve are related more to structural differences between adult and fetal hemoglobins; cellular pH moves closer to the values of adult red cells. In goats of this age the predominate hemoglobins are those with β chains and these have dissociation curves shifted further to the right than other adult hemoglobins.
In young lambs Hb-C is found only in association with Hb-A but the amount present seldom exceeds 5 to 10%. The oxygen affinities of sheep Hb-A and Hb-C are identical but higher than that of sheep Hb-B.     

The ontogenesis of monoaminergic nerve fibres in the hypophysis of Rana temporaria with special reference to the pars distalis

Summary In Rana temporaria tadpoles, fluorescent fibres appear in the prospective eminentia mediana, the pars intermedia and the pars distalis at Gosner's stage 25. During prometamorphosis the amount of fluorescent material increases around the developing primary capillary plexus in the eminentia mediana. In the pars intermedia the fibres form a dense fluorescent network but in the pars distalis the fibres are few and delicate.At stages 42–43, the onset of climax, the pars distalis fibres disappear. The possible functional significance of the pars distalis fibres is discussed.The background adaptation ability appears at stages 28–29, while the fluorescent pars intermedia innervation is observable at stage 25.     

Sero-prevalence,risk factors and distribution of sheep and goat pox in Amhara Region,Ethiopia

Background

Sheep pox and goat pox are contagious viral diseases of sheep and goats, respectively. The diseases result in substantial economic losses due to decreased milk and meat production, damage to hides and wool, and possible trade restriction. A study was undertaken in Amhara region of Ethiopia. A cross-sectional study design was used to estimate the sero-prevalence and identify associated risk factors, while retrospective study design was used to assess the temporal and spatial distribution of the disease. A total of 672 serum samples were collected from 30 Kebeles and tested using virus neutralization test.

Results

From a total of 672 sera tested, 104 (15.5%) were positive for sheep and goat pox virus antibody; from which 56 (17%) were sheep and 48 (14%) were goats. The diseases were prevalent in all study zones, the highest sero-prevalence was observed in South Gondar (20.9%) and the lowest in North Gondar and West Gojjam zones (11.9% each). From the potential risk factors considered (species, sex, age, agro-ecology and location); only sex and age were significantly associated (p?<?0.05) with the diseases in multivariable logistic regression. Female and young animals were at higher risk than their counterparts. From January 2010 to December 2014, a total of 366 outbreaks, 12,822 cases and 1480 deaths due to SP and 182 outbreaks, 10,066 cases and 997 deaths due to GP were recorded in Amhara National Regional State.

Conclusion

Both the serological and the outbreak data revealed that sheep and goat pox is one of the most prevalent and widespread diseases of sheep and goats in the study area. Hence, annual mass vaccination program must be implemented for economic and viable control of sheep and goat pox diseases in the Amhara region in particular and at a national level in general.

     

Presence of species-specific, monomorphic antigens on sheep and goat binucleate cells

Immunocytochemical assays for sheep and goat species-specific, monomorphic antigens were developed utilizing polyclonal antisera from sheep and goats immunized by interspecific pregnancy. The assays were applied to cell isolates from sheep and goat fetal cotyledons collected from allogeneic pregnancies at Days 35, 40 and 120 of gestation. The isolates contained 7 to 48% binucleate cells (BNC). Using these assays, the sheep-specific antigen was detected on sheep cotyledonary cell isolates on all days of gestation tested (P < 0.001); the assay also detected the antigen on the BNC subset of the cotyledonary cell isolate population (P < 0.001). The caprine-specific antigen was shown to be present on cotyledonary cell isolates (P < 0.05), although the presence of the antigen could not be demonstrated with statistical confidence on goat BNC due to insufficient numbers of discernible cells. Binucleate cells contribute to the formation of the syncytial layer of the placenta by fusing with maternal epithelial cells and with the syncytium. The species-specific antigen (or antigens) is present on BNC at the appropriate time of gestation at which it (they) could play a role in the humoral immune response to interspecific and hybrid pregnancies observed in ewes and does.     

Successful pregnancy in goats carrying their genetically identical conceptus

Mammalian pregnancies are naturally allogeneic, but syngeneic pregnancies have been carried to term in laboratory animal species. The need for maternal immune recognition during mammalian pregnancy is still unclear. Allogeneic pregnancies are protected from maternal immune attack by the nature of the trophoblast and its interactions with maternal tissues at the maternal-fetal interface. Syngeneic pregnancy models and the success of pregnancies in immunosuppressed mice challenge the necessity of a maternal immune response in mammals. This study was designed to investigate if outbred, domestic sheep and goats can successfully establish and maintain a syngeneic pregnancy. Embryo splitting and cryopreservation techniques were used to enable sheep and goat demi-embryos to be transferred to genetically identical females. Allogeneic pregnancies were established from the transfer of demi-embryos subjected to the same manipulations to assess demi-embryo survival and pregnancy rates under conventional immune compatibility conditions. Syngeneic pregnancies were established and carried to term in goats (2/11) but not in sheep (0/24). Microsatellite and DNA fingerprinting analyses confirmed that each kid was a genetically identical twin to the female that carried it to term. Our results demonstrated that genetic disparity is not required for the establishment and maintenance of pregnancy in goats, but our results were inconclusive for sheep.     

Activities of glutathione-S-transferase and ethoxycoumarin-O-deethylase in tissues of camels, sheep, goats and rats.

1. The activities of the drug metabolizing enzymes ethoxycoumarin-O-deethylase, glutathione-S-transferase, and protein concentrations were measured in vitro in the liver, kidney and duodenal mucosa of camels, sheep, goats and rats. 2. Enzyme activities were generally higher in the liver than in the kidney and duodenal mucosa in the four species studied. 3. The activities of ethoxycoumarin-O-deethylase and glutathione-S-transferase in liver of male kids were about one third and half of that in adult male goats, respectively. In the kidney and duodenal mucosa of male kids, the activity of glutathione-S-transferase was about 70% and 53% of that in the mature male goat, respectively. In the latter tissues, however, there was no detectable activity of ethoxycoumarin-O-deethylase. 4. In general, goats and sheep had similar activities of the two enzymes which were significantly higher than those found in camels and rats. 5. Some sex-related differences were noted in the activity of the two enzymes studied. Female sheep had significantly higher hepatic glutathione-S-transferase than the male: while the enzyme activity in the kidney and duodenal mucosa of male goats was significantly higher than in females. Male rats had higher hepatic ethoxycoumarin-O-deethylase activity than females.     

Attempted cross-transmission of coccidia between sheep and goats and description of Eimeria ovinoidalis sp. n.

Attempted infection of 2 young lambs with oocysts of Eimeria christenseni from a goat was unsuccessful. Negative results were obtained also when young kids were fed oocysts of Eimeria ninakohlyakimovae from sheep. There was no difficulty in infecting lambs with the sheep coccidium resembling E. ninakohlyakimovae nor goats with the goat coccidium E. christenseni. Oocysts from the goat measured 38.4 X 26.7 microns, but were easily distinguished from Eimeria ahsata from the sheep by sporocyst size and shape, and from Eimeria ovina by oocyst size. Eimeria ninakohlyakimovae-like oocysts from sheep averaged 23.0 X 18.2 microns and were morphologically indistinguishable from previously reported goat coccidia. Since no cross infections of sheep and goats could be accomplished with oocysts of Eimeria sp. characteristic of one or the other host, I concluded that sheep coccidia previously known as E. ninakohlykimovae are distinct from morphologically similar goat coccidia and therefore constitute a separate species. Since the name E. ninakohlyakimovae was first used for coccidia from the goat, the sheep coccidium is renamed Eimeria ovinoidalis with oocyst structure and endogenous stages similar to those previously described from the sheep.     

Attempted Cross-Transmission of Coccidia Between Sheep and Goats and Description of Eimeria ovinoidalis sp. n.

SYNOPSIS.
Attempted infection of 2 young lambs with oocysts of Eimeria christenseni from a goat was unsuccessful. Negative results were obtained also when young kids were fed oocysts of Eimeria ninakohlyakimovae from sheep. There was no difficulty in infecting lambs with the sheep coccidium resembling E. ninakohlyakimovae nor goats with the goat coccidium E. christenseni. Oocysts from the goat measured 38.4 × 26.7 m, but were easily distinguished from Eimeria ahsata from the sheep by sporocyst size and shape, and from Eimeria ovina by oocyst size. Eimeria ninakohlyakimovae -like oocysts from sheep averaged 23.0 ×18.2 m and were morphologically indistinguishable from previously reported goat coccidia.
Since no cross infections of sheep and goats could be accomplished with oocysts of Eimeria sp. characteristic of one or the other host, I concluded that sheep coccidia previously known as E. ninakohlyakimovae are distinct from morphologically similar goat coccidia and therefore constitute a separate species. Since the name E. ninakohlyakimovae was first used for coccidia from the goat, the sheep coccidium is renamed Eimeria ovinoidalis with oocyst structure and endogenous stages similar to those previously described from the sheep.