Sheep Of Different Ages Research Articles

Distrofia muscular nutricional em ovinos na Paraíba

Descreve-se um surto de distrofia muscular nutricional em ovinos no semi-árido Nordestino. Foram afetados animais de 3-4 meses de idade, da raça Dorper, pesando 30-40 kg. Os animais eram alimentados, à vontade, com leite, ração balanceada, capim Tifton e sal mineral. Dos 70 animais Dorper, 6 adoeceram e morreram em um período de 48 horas. Apresentaram temperatura, entre 40 e 41ºC, incoordenação com posterior paralisia e decúbito, depressão, prostração e diminuição dos reflexos pupilar e de ameaça, flacidez da língua e mandíbula, salivação, edema submandibular, dispnéia e aumento da freqüência cardíaca. A morte ocorreu após curso clínico de 6- 12 horas. Na necropsia de 3 animais, os músculos esqueléticos estavam de coloração pálida, o fígado estava aumentado de volume e de coloração amarelada, os gânglios parotídeos, submandibulares, retrofaríngeos, prescapulares e mediastínicos estavam aumentados de volume e avermelhados e os pulmões apresentavam áreas vermelhas. Na histologia havia necrose segmentar de todos os músculos examinados e congestão dos gânglios linfáticos e pulmão. Posteriormente mais três animais adoeceram, sendo tratado com oxitetraciclina e complexo vitamínico A,D e E. Desses 3 animais, 2 morreram e um sobreviveu. Na mesma fazenda havia e não adoeceram 20 ovinos da raça Santa Inês, da mesma idade que os animais afetados, que recebiam a mesma alimentação exceto o leite, e 900 ovinos de outras idades. A superalimentação em animais com rápido crescimento e o estresse causado pela restrição de água durantes 2 dias, para aumentar o consumo de leite, parecem ter sido fatores predisponentes para a ocorrência da doença. É possível, também, que algum dos minerais suplementados tenha antagonizado o Se presente na alimentação.

Load distribution of articular cartilage from MR-images by neural nets

Artificial neural nets were used to determine the Young's modulus and spatial load distribution in articular cartilage by means of T2-weighted MR imaging. MR images were obtained in vitro (ex vivo?) from the joints of sheep of different ages (3 months, 9 months, 15 months, 1.5 years, 5 years, 5.5 years) and pigs (4 and 6 months) with a Bruker AMX 300 (7 T) spectrometer equipped with a micro-imaging unit. The knee of a 29-year-old male volunteer was studied in vivo under mechanical load using a clinical Siemens Vision MRT (1.5 T). The load of the cartilage is understood as a non-linear image transformation of loaded versus unloaded images. The artificial neural net was used to recognize given reference pixels of the unloaded cartilage within the image of the loaded cartilage. The Young's modulus was calculated from the local strain and the external pressure using the Hooke's law. With this method, the average Young's modulus was obtained in relationship to the biological age of the cartilage. The investigated age interval showed a progressive increase of 0.5 ± 0.3 MPa per year. These results are consistent with published results. As shown in this pilot study, the method of neural nets allows the visualization of the spatial load distribution within the articular cartilage.

Outbreaks of pythiosis in two flocks of sheep in northeastern Brazil.

Two outbreaks of cutaneous pythiosis caused by Pythium insidiosum were diagnosed in two herds of crossbred hair wool sheep of different ages in the semiarid region of Northeastern Brazil. In one herd of 120 sheep, 40 were affected. The other outbreak affected six sheep out of 80. Local swellings with ulcerative lesions were observed in the limbs and abdominal and prescapular regions. Three sheep were necropsied. Two of them had lung metastasis characterized by multifocal nodules measuring 0.5-2 cm. In one animal, the prescapular lymph node was also affected. In another, the cutaneous lesion extended to the sesamoid bone. Microscopically, there were multifocal granulomas with intralesional P. insidiosum hyphae and Splendore-Hoeppli material surrounding the hyphae. The diagnosis was based on the histologic lesions, immunohistochemical identification, and culture of the etiologic agent. One sheep treated with potassium iodide recovered. Standing in swampy water for long periods in a warm aquatic environment seems to be the reason for the high prevalence of the disease.

Experimental Transmission of Ovine Herpesvirus-2 in Sheep

Transmission of ovine herpesvirus-2 (OvHV-2) in sheep via natural contact and nasal secretions was examined. OvHV-2-free lambs were produced by separating newborn lambs from their mothers within 5 days of birth and raising them in an isolation facility. Transmission experiments via natural contact were conducted by keeping OvHV-2-free lambs with OvHV-2-infected sheep of different ages. Six of the infected ewes in this experiment were pregnant and gave birth during the experimental period. OvHV-2 was not transmitted from the adult sheep, though viral DNA was consistently detected in their peripheral blood leukocytes (PBL). On the other hand, OvHV-2 was transmitted from recently infected lambs to sheep at 10 or 12 weeks after the onset of contact. In addition, we attempted the experimental transmission of OvHV-2 via nasal secretions, by transferring nasal washings from infected sheep to the nostrils of uninfected sheep. Sheep receiving the nasal washings from infected adult sheep maintained their negative status for 15 months, whereas sheep receiving nasal washings from recently infected lambs acquired OvHV-2 by 8 months. The results of these experiments support that OvHV-2 is more easily transmitted to negative sheep by recently infected lambs than by adult sheep. Further, it is supposed that the nasal cavity is a portal for entry and shedding of infectious OvHV-2 in sheep.

Prevalence, intensity, and fertility of ovine cystic echinococcosis in the central Peruvian Andes

An abattoir survey of 212 sheep of different ages was undertaken to determine the local epidemiological transmission patterns of Echinococcus granulosus in the central Peruvian Andes. Overall prevalence of the disease in sheep in this survey (which ended in July 1996) was 77·4%, with 96% of sheep aged ⩾6 years being infected. Of 1165 cysts examined, 41·1 % were fertile with a mean protoscolex viability of 73·2%. A logistic regression model for the distribution of cyst fertility and type by age, location and size is described. Mathematical modelling also determined that infection pressure on sheep was 0·44 infections per year and that the mean number of cysts increased linearly by 1·28 cysts per year. These data suggest that E. granulosus is in an endemic state in this area and control measures could drive the disease towards extinction.

Serological Investigation of Granulocytic Ehrlichia Infection in Sheep in Norway

Serum samples of 749 sheep from 75 sheep flocks in Norway, i.e. 361 lambs (6 to 7 months old) and 388 adults (>1.5 year), were analysed for antibodies to Ehrlichia equi. Ten animals from each flock were examined. Seropositive animals were found along the coast of southern Norway from Vestfold to Sør-Trøndelag (as far north as 63°38'N). Seropositive sheep were not found in southeast, east or northern Norway. Thirty-two flocks were seropositive, although tick-borne fever had only been diagnosed earlier in half of these. In 78% of the seropositive flocks, more than 80% of the sheep were seropositive. A total of 35.7 % and 36.3 % of lambs and adults were found seropositive, respectively. However, the overall seroprevalence among animals that had been grazing on Ixodes pastures were 0.80 for the lambs and 0.84 for the adults. Mean antibody titres (± SD) (log10) in seropositive lambs and adults were 2.59 (± 0.449) and 2.70 (± 0.481), respectively. No significant differences in either seroprevalence or mean antibody titre between sheep of different ages were obtained in this study. Based on antibodies 94% of sheep flocks on Ixodes pastures were infected with a granulocytic Ehrlichia infection. The association between seropositive flocks and Ixodes infested pasture shows a very high degree of agreement (p < 0.00001). The present study indicates that granulocytic Ehrlichia infection in sheep is underdiagnosed in Norway.

Ontogeny of IGF-I responsiveness to bGH in young lambs☆

The ontogeny of hepatic growth hormone (GH) receptors (GHR), as measured by responses of both plasma insulin-like growth factor-I (IGF-I) and hepatic GHR to an exogenous bGH stimulus, was examined using sheep of different ages (Days 1–7, 14–21, 28–35, and 56–63 of life, and yearlings). The IGF-I response to bGH was first examined in yearling sheep using two doses of bGH (0.1 and 0.2 mg/kg LW/d). Based on these results, lambs in four groups up to Day 63 of life were treated for 5 d with bGH ( n = 10) at a dose of 0.15 mg/kg LW/d or with saline ( n = 10). Jugular blood samples were taken once daily on Days −1, 4, and 5 of treatment. bGH treatment in lambs up to Day 63 of life had little effect on plasma concentrations of GH, insulin, glucose or urea, but significantly (P < 0.05) increased circulating concentrations of IGF-I at all ages and of NEFA at Day 62/63 of life. In contrast, bGH treatment at either dose in yearlings significantly increased these parameters, except for plasma urea concentrations which were decreased in bGH-treated yearlings. However, the responses of plasma IGF-I concentration to bGH stimulus in lambs up to Day 63 of life were small compared to those in yearling sheep. Consistent with this, bGH treatment failed to affect hepatic GH binding in young lambs, but up-regulated it in yearling sheep. Furthermore, basal (unstimulated) GH binding did not differ between sheep of 7 vs. 63 vs. 365 d of age, despite the greater IGF-I responses to bGH in the latter group. It is suggested that hepatic GHR in lambs up to Day 63 of life are not fully functional compared to the situation in yearlings.

Methane emissions from sheep

A total of 1137 observations from sheep of different age fed with rations of different composition were collected from the literature. This study used measures of methane emissions from sheep under different feeding conditions to compute regression equations to predict methane emissions from ration descriptive variables. It was also tested whether the material validated other common prediction equations. Methane emissions from all sheep averaged 22.15 g day −1. For growing sheep and adult sheep they equalled 23.16 g day −1 and 20.48 g day −1, respectively, with significant differences ( P ≤ 0.05). The percentage loss of methane (% of gross energy intake) averaged 7.22, 7.23 and 7.22%, respectively. Methane emissions increased ( P ≤ 0.05) with increasing live weight, feeding level measured as multiples of maintenance and digestibility of dry matter and decreased for rations with wider ratios of crude fibre intake and intake of N-free extracts. Crude fibre content in the ration and energy density of the ration showed no clearly identifiable effect on methane emissions.

Changes in the fatty acid composition of stored erythrocytes from sheep of different ages

This study examined the profile in sheep erythrocyte fatty acids from animals of different ages during storage at 4°C in a nutritive medium for up to 6 days. The changes found in the fatty acyl profile were a decrease ( P<0.01) in the percentage of arachidonic acid and an increase ( P<0.01) in the percentage of minor fatty acids (representing < 2% in each case; 20:2, 22:0 and 22:1) with respect to fresh erythrocytes in all age groups. However, the saturated/unsaturated ratios and unsaturated index started almost constant in all cases. The changes observed occurred after 24–48 h of storage, with significant increases ( P<0.01) in the fluorescence detected in the lipid extracts from stored erythrocytes during this period. The above findings suggest peroxidative damage and changes in the erythrocyte lipid membrane during storage.

Whole body metabolism of cysteine and glutathione and their utilization in the skin of Romney sheep: consequences for wool growth

SUMMARYInfusion of [35S]-labelled cysteine into the jugular of Romney sheep of different ages was used to estimate the extent of combined cysteine and cystine (cyst(e)ine) and glutathione (GSH) interchange in various tissues, including skin, and to measure whole body irreversible loss rates (1LR) for cyst(e)ine. The studies were undertaken at Palmerston North, New Zealand during 1990 and 1991.Reverse phase HPLC using a fluorigenic reagent, 7-fluoro-2,1,3-benzoxadiazole-4-sulphonate (SBD-F) was used for the simultaneous determination of thiols (cysteine and GSH) in whole blood (bound and free fractions), liver, kidney, small intestine, muscle, pancreas and skin. The appearance of [35S]-label in thiol compounds and their oxidation products was determined by ion-exchange HPLC. Specific radioactivities (SRA) for cyst(e)ine and GSH derived from this data showed equivalence for cysteine and GSH SRAs in all tissues, except for whole blood, indicating rapid withintissue interconversion between these thiols. In whole blood, however, the very low SRA for GSH (&lt; 4 DPM/nmol) compared to cyst(e)ine (250 DPM/nmol) indicated markedly slower or negligible exchange with red blood cell GSH, and hence little inter-organ transport of [35S]-label as GSH.Close infusion of [35S] cysteine into a defined patch of skin and collection of the venous outflow permitted directin vivomeasurement of the proportional uptake of cysteine by the skin. Results indicated considerable variation in the uptake of cysteineper se(20–40%) but no, or very little, oxidation of cysteine in the skin and no net export of GSH.The combination of whole body, tissue and skin specific studies of [35S]-labelled cysteine metabolism quantitatively confirmed the very high proportion of circulating cyst(e)ine in sheep which is directed to skin and wool protein synthesis alone, and highlighted those aspects of this metabolism which are of most importance to wool production.

Preferential release of tri-iodothyronine following stimulation by thyrotrophin or thyrotrophin-releasing hormone in sheep of different ages

The influence of TRH and TSH injections on plasma concentrations of tri-iodothyronine (T3) and thyroxine (T4) was investigated in neonatal (injection within 0.5 h after delivery) and growing lambs and in normal, pregnant and lactating adult ewes (all 2 years old and originating from Suffolk, Milksheep and Texal crossbreeds). Neonatal lambs had higher levels of T3, T4 and GH compared with all other groups, whereas prolactin and TSH were higher in lactating ewes. In all animals, injections of TRH increased plasma concentrations of prolactin and TSH after 15 min but not of GH at any time. Small increases in T3 and T4 were observed in neonatal lambs, without any effect on the T3 and T4 ratio, after prolactin administration, whereas prolactin did not influence plasma concentrations of T3 or T4 in all other experimental groups. Similar results for thyroid hormones were obtained after TRH or TSH injections. It was therefore concluded that the effects observed after TRH challenge were mediated by the release of TSH. With the possible exception of neonatal lambs, plasma concentrations of T3 after administration of TRH or TSH were always increased before those of T4; the increase in T3 occurred within 0.5-1 h compared with 2-4 h for T4 in all experimental groups. This resulted in an increased ratio of plasma T3 to T4 up to 4 h after injection. It is concluded that, in sheep, TRH and TSH preferentially release T3 from the thyroid gland probably by a stimulatory effect of TSH on the intrathyroidal conversion of T3 to T4.

Postpubertal Maturation of Endogenous Opioid Regulation of Luteinizing Hormone Secretion in the Female Sheep1

This study investigated whether the role of endogenous opioid peptides in the suppression of LH secretion during seasonal anestrus in the sheep changes with age. The experimental approach was to determine the effect of blockade of opioid receptors with naloxone on LH secretion at different times of year within the anestrous season, and to compare responses between seasonally anestrous sheep of different ages. Sheep, all past the normal age of puberty, were ovariectomized before the study and treated s.c. with estradiol implants to provide a fixed estradiol feedback signal. One-year-old females responded to naloxone with a rapid increase in LH pulse frequency in the early (April) and late (August) phases of their first anestrous season. This response was similar to that previously found in prepubertal female sheep. Only 5 of the 8 females responded to the same naloxone challenge in mid anestrus (June), suggesting that the contribution of opioid pathways to the inhibition of LH secretion at this time of year is not necessarily the same as that in early and late anestrus. None of the older anestrous sheep (greater than or equal to 2 yr) responded to naloxone in June, indicating age-related changes in the role of endogenous opioid mechanisms in the inhibition of LH secretion. Ovary-intact mature sheep did not respond to naloxone, in contrast to our previous observations in intact prepubertal females. We infer that the neural mechanisms underlying the superficially similar hypogonadotropic states that occur during the prepubertal period, first anestrous season, and later anestrous seasons are not identical.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in the phospholipid and fatty acid composition in normal erythrocytes from sheep of different ages. Aminophospholipid organization in the membrane bilayer

Development and aging processes in mammals are associated with changes in several physiological parameters. The aim of the present study was to investigate the changes in erythrocyte lipid composition during sheep development. In all the age groups studied, cholesterol/phospholipid ratios remained constant, at close to unity, while phospholipid patterns (sphingomyelin: 45–51%, phosphotidylethnolamine: 26–33%, phosphatidylserine: 13–19% and phosphatidylcholine: <2%) changed during development, with a statistically significant decrease ( P < 0.01) in phosphatidylserine and an increase in sphingomyelin content. These data suggest an increase in the rigidity of the erythrocyte lipid bilayer in adult sheep when compared with 1-month-old animals due to a decrease in the phosphatidylserine/sphingomyelin ratio. Fatty acid profiles consistently showed 5 main acids: oleic (52–54%), stearic (17–18%). linoleic (9–15%), palmitic (8.5–11%) and arachidonic acid (2–3%) and arachidonic acid (2–3%), mainly with significant variations ( P < 0.01) in palmitic and linoleic acid contents, respectively reaching the highest and lowest percentages in the youngest sheep. However, the developmental process seems to have no influence on the aminophospholipid topology of erythrocytes. This study suggests that the animals' developmental process has a marked effect on the lipid composition of erythrocyte membranes, which could affect cell functions.

Social organization of Merino sheep of different ages, sex and family structure

Four different groups of Merino sheep were established and social interactions were examined in paddocks which were barren or with trees and other topographic features. Two groups had been established for 2 years. One group consisted of ewes of the same age and the other contained mothers and their unweaned offspring aged 2 and 1 year. Two other groups were established recently: one consisted of sheep of different sexes whose ages ranged from 1 to 5 years and the other group contained ewes of two different age groups. Age effects on cohesive and aggressive behaviours were apparent, with older animals being involved in more fights (usually between themselves), initiating more movements and showing more attention behaviours. In dominance tests the number of fights was significantly higher in the single sex, single age group. In the field, the family group was markedly less responsive in terms of fighting, movement and attention behaviours when compared with the other social groupings. This effect was most obvious in the barren environment. If a behaviour was observed frequently in one member of a family group it normally occurred in the other members of that family. It was twice as likely if the mother of the family initiated a movement that it would be followed by one of her descendants and particularly the younger one. The level of fighting was no different between members of the same family as between members of different families. The evidence for the family group being a socially more complex unit than the other three groups is discussed. The possibility is raised that a socially complex group may be less affected by environmental heterogeneity than groups that were not as well integrated socially.

Specific radioimmunoassay for ovine bone gla-protein (osteocalcin).

We developed a sensitive and specific radioimmunoassay for ovine bone gla-protein (osteocalcin) using a polyclonal rabbit antibody raised against ovine bone gla-protein. Bone from lambs was extracted in 0.5 mol/l EDTA and desalted on Sephadex G-25. Bone gla-protein was purified by gel filtration chromatography over Sephadex G-100 and ion-exchange chromatography on DEAE-Sephadex A-25. The protein, subjected to monodimensional electrophoresis migrated as a single spot in SDS PAGE with the same apparent molecular weight of 12 kD as bovine bone gla-protein. The amino acid composition of purified bone gla-protein was in agreement with a previous publication. The competitive RIA uses 125I-labelled bone gla-protein as a tracer and a complex of a second antibody and polyethylene glycol to separate free and antibody-bound 125I-labelled bone gla-protein. The intra- and inter-assay variations are less than 6 and 10%, respectively. There is no reactivity of our antisera with dog sera. The cross-reactivity is only partial with calf and human sera and complete with ovine sera. We measured bone gla-protein levels in serum of 96 normal male sheep of different ages. Serum bone gla-protein rapidly and significantly (P less than 0.001) decreased from 535 +/- 169 microgram/l at birth, to 240 +/- 43 microgram/l at 45 days, 152 +/- 44 micrograms/l at 90 days, and 5.9 +/- 0.7 microgram/l at 7 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Flux of inorganic phosphate across the sheep rumen wall in vivo and in vitro.

Experiments were done in vivo and in vitro to study the flux of inorganic phosphate (P1) across the rumen wall in sheep. The technique of the temporarily isolated and washed reticulo-rumen was applied to measure P1 net flux at nine different P1 concentrations in the buffer solutions introduced into the reticulo-rumen for 1 h. Six sheep were either P replete (4.25 g P d-1) or in a P-depleted state (1.05 g P d-1). Under both dietary treatments P1 net secretion into the reticulorumen was found at P1 concentrations between 0.1 and 2.2 mmol l-1 whereas P1 net absorption was observed at P1 concentrations between 4.1 and 15.8 mmol l-1. There were positive linear relationships between P1 concentration and P1 net flux for the whole concentration range studied in repleted and in depleted sheep. There were no indications of active transport components or saturation phenomena. Unidirectional P1 fluxes were then measured in Ussing chambers with 32P using a total of 100 rumen wall epithelia obtained from eighteen sheep of different ages. No P1 net flux was found under short-circuit conditions. Experiments with changed potential differences (+25 or -25 mV at serosal side) showed that P1 flux was influenced by the electrical gradient indicating electrogenic phosphate ion diffusion without involvement of active transport processes. Critical evaluation of the obtained unidirectional flux ratios suggests that part of the P1 flux was electroneutral, e.g. by ion exchange or cotransport. The results from these studies show that the reticulo-rumen substantially contributes to phosphate absorption from the sheep gastrointestinal tract.

Biological activity of thymus preparations from sheep of different ages

Biological activity of thymus preparations from sheep of different ages

The utilization of gelled maize starch in the small intestine of sheep.

1. A solution of gelled maize starch and Cr-EDTA was continuously infused for 4 weeks via the abomasum into sheep of different ages. The proportions of infused α-glucoside passing the terminal ileum as glucan (ethanol-precipitable α-glucoside), dextrins (ethanol-soluble glucose polymers) and glucose, and the glucan and over-all α-glucoside disappearances in the small intestine were determined. Ethanol-soluble α-glucoside compounds in ileal digesta were further separated by paper chromatography.2. Glucan was efficiently degraded, since little reached the terminal ileum. Most of the α-glucoside in ileal digesta consisted of glucose and dextrins (mainly short chain length oligosaccharides), suggesting that α-amylase activity was not limiting over-all starch utilization.3. No adaptation of intestinal starch utilization was evident except that the proportion of infused α-glucoside passing the terminal ileum as glucose decreased with time.4. A negative correlation existed between the pH and the total α-glucoside content of the ileal digesta, possibly relating to changes in the microbial activity.5. The advantages and disadvantages of feeding with starch so as to by-pass rumen fermentation are discussed.

Electrolytes and water in the brain and cerebrospinal fluid of the foetal sheep and guinea-pig.

1. Samples of cisternal cerebrospinal fluid (c.s.f.) and blood plasma have been obtained nearly simultaneously from foetal sheep of different ages, the foetus having been exteriorized and maintained in a normal state with respect to its blood gases and arterial pH. The brains were removed from these foetuses and also from foetal guinea-pigs after exsanguination.2. A comprehensive study has been made of the concentrations of water, chloride, sodium, potassium, calcium and magnesium in blood plasma, c.s.f. and brain from foetal sheep and in brain from foetal guinea-pigs during development in utero. Maternal arterial blood plasma, cisternal c.s.f. and brain from the sheep and brain from the guinea-pig have been analysed for comparison.3. Concentrations of the ions analysed in foetal blood plasma are similar to those found by others in the sheep and other species. In the case of calcium, the results suggest an active maintenance of the concentration of this ion in foetal plasma by the placenta.4. The chloride concentration in c.s.f. at ages between 65 days and term (147 days) averaged 1.19 times that in foetal plasma, but only 1.08 at 45-50 days; the sodium concentration in c.s.f. was also slightly reduced at this time. The increase in the c.s.f./plasma ratios for chloride and sodium appears to coincide with the first development of the blood-brain and blood-c.s.f. barriers to non-electrolytes.5. Magnesium was at a slightly higher concentration in c.s.f. than in plasma at all foetal ages and did not vary with age. The concentrations of potassium and calcium in c.s.f. were high at early ages and fell to reach adult concentrations after birth: the mechanisms determining the concentrations of the various ions in c.s.f. develop at very different, largely independent, rates.6. The water content of the cerebral hemispheres of the foetal sheep was stable at 90% of the wet weight till 105 days and fell thereafter. The contents of chloride, sodium and potassium followed paraboloid relations with age. Chloride and sodium reached a peak of 62 and 81 m-equiv/kg respectively between 89 and 105 days in the sheep. Potassium was at a minimum of 65 m-equiv/kg at the same time. The content of water and these electrolytes in the cerebral hemispheres of the foetal guinea-pig underwent similar changes, the maxima and minimum occurring as in the sheep at two-thirds of the total length of the pregnancy, namely 65 days in the guinea-pig. At 46 days in the guinea-pig, chloride in brain reached 53 m-equiv/kg, sodium was 68 m-equiv/kg and potassium was 75 m-equiv/kg. In contrast to the sheep, no reversal of the sodium-potassium ratio occurred. These changes in water and electrolytes probably represent a rise, a peak and a decrease in the volume of the extracellular space of cerebral cortex, but changes in the volume occupied by a cell-type, containing much intracellular chloride and sodium, could also contribute to this phenomenon.7. The calcium content in the cerebral hemispheres of the foetal sheep remained at about 3.0 m-equiv/kg throughout pregnancy. Magnesium in the cerebral hemispheres of both the foetal sheep and the guinea-pig showed a trough in concentration during pregnancy which corresponded approximately in position to the minimum in potassium content and the maxima in chloride and sodium contents. Lowest values were 9.6 m-equiv/kg at 105 days in the sheep and 9.5 m-equiv/kg at 51 days in the guinea-pig.

Dicrocoelium Dendriticum (Rudolphi, 1819) Looss, 1899 in Turkey I. Field Studies of Intermediate and Final Hosts in the South Marmara Region, 1968

SUMMARY This study was conducted throughout the year 1968, with the object of determining the incidence of D. dendriticum infection in sheep of different ages, and of identifying the first and second intermediate hosts (land snails and ants respectively) at two places which are representative of South Marmara geographic region: Karacabey State Farm, Bursa, and Kumkale State Farm, Canakkale. The mean infection rate in sheep one year old or more was 64 per cent at Karacabey and 74 per cent at Kumkale, being higher in older sheep. In lambs born in winter 1967–1968, the first eggs of D. dendriticum were observed in the faeces in August 1968 at Karacabey and November 1968 at Kumkale. These observations indicate that lambs began to acquire their infections during the period May and June. A total of 14,684 land snails was collected from the grazing areas of sheep on the two farms (8282 from Karacabey and 6402 from Kumkale), identified, and examined for the larval stages of D. dendriticum. Helicopsis krynickii (Andrz.), H. protea (Rossm.), Cernuella virgata (D.C.) and Trochoidea pyramidata (Drap.) are new snail hosts records. Helicella candicans (Pfr.), Helicopsis derbentina (Andrz.), Monacha carthusiana (Mull.), and Cochicella acuta (Mull.), which are known hosts in Europe and Russia, have been recorded as hosts for the first time in Turkey. Infection rates in these snails ranged from 0.3 to 41.6 per cent. Monthly observations showed that snails were infected from April to December, with highest infection rates in summer and autumn.