Aldrin epoxidase and 7-ethoxyresorufin-O-deethylase (EROD) activity in livers from lambs of three different breeds of Norwegian sheep

The concentration of aldrin epoxidase was significantly greater in the livers of Norwegian Pelt lambs than in those of Rygja lambs but did not differ significantly between either of these two breeds and Spael lambs. Conversely, although there was no detectable EROD activity in the livers of many of the lambs in all three breeds, the median activity was greater in the livers of Rygja lambs than was the case for Spael lambs.Abbreviations EDTA ethylenediaminetetraacetic acid - EROD 7-ethoxyresorufin-O-deethylase - GST glutathioneS-transferase     

Microsomal enzymes in lambs and adult sheep,and their possible relationship to alveld

The difference in susceptibility to alveld between lambs and adult sheep may be caused by differences in the microsomal enzyme activities in their livers. There was no difference in NADPH-cytochrome c reductase or 7-ethoxyresorufin-O-deethylase (EROD) activity between ewes, control lambs and phenobarbitone-dosed lambs 3 weeks after dosing ceased. However, aldrin epoxidase activity was at that time significantly highest in the phenobarbitone-dosed lambs and significantly lowest in the ewes. The liver cytosolic glutathione transferase activity was significantly highest in the ewes and significantly lowest in the control lambs at the same time.     

Fungi onNarthecium ossifragum leaves and their possible involvement in alveld disease of Norwegian lambs

Spores ofPithomyces chartarum (Berk. & Curt.) M.B. Ellis were only rarely seen on leaves ofNarthecium ossifragum (L.) Hudson collected in summer from five areas in western Norway in which alveld, a photosensitization disease of lambs, is endemic.Cladosporium magnusianum (Jaap) M.B. Ellis was found on all 118 leaf samples collected in the summers of 1990 and 1991. The hypothesis thatP. chartarum contributes to the aetiology of alveld could not be supported, but it is possible thatC. magnusianum may have a role in the causation of the disease.     

Glycogen accumulation and histological changes in the livers of lambs with alveld and experimental sporidesmin intoxication

Alveld is a hepatogenous photosensitization disease seen in lambs grazing Narthecium ossifragum pastures in Norway. Mycotoxins, possibly sporidesmin, have been suspected to cause the liver damage in alveld as in facial eczema. The histological changes in the liver of alveld cases and in lambs photosensitized after experimental sporidesmin intoxication were compared. The liver damage characterized by necrosis in single centrilobular hepatocytes, was of the same type in both conditions. Minor to moderate portal fibroplasia and bile duct proliferation were almost always present. Accumulated glycogen was seen in hepatocytes in the centrilobular areas. This was significantly correlated to the enzymatically measured glycogen content and there was good correlation between parenchymal damage and glycogen accumulation. The glucose-6-phosphatase and glycogen phosphorylase activities were normal. These findings indicate that parenchymal damage, rather than obstruction of the bile ducts, caused the retention of phylloerythrin both in alveld cases and in experimentally sporidesmin-intoxicated lambs. The accumulation of glycogen could not be explained.Abbreviations HE haematoxylin and eoson - PAS periodic acid Schiff - EDTA ethylene diamine tetracetic acid     

Failure to induce toxicity in lambs by administering saponins from Narthecium ossifragum

It has been suggested that saponins produced by Narthecium ossifragum (Bog asphodel) may be the direct cause of the toxicity leading to the hepatogenous photosensitivity disease alveld seen in Norwegian lambs. Lambs fed large quantities of freeze-dried N. ossifragum did not develop alveld. Chemical investigations on the freeze-dried material and fresh N. ossifragum showed no difference in their saponin content. These results indicate that alveld is not caused solely by the saponins produced by N. ossifragum.     

Levels of oestrone sulphate during pregnancy in different breeds of cows and its possible association with retained foetal membranes.

The levels of oestrone sulphate in plasma of pregnant cows was followed from 30 days of pregnancy until parturition. The Swedish Jersey Breed (SJB) showed significantly lower levels of oestrone sulphate between 101 and 200 days of pregnancy than either the Swedish Red and White (SRB) or the Swedish Lowland Breed (SLB). No significant difference was noted between SRB and SLB. On days 141-160 of gestation the oestrone sulphate values were still below the 10 nmol/l level for the SJB while they were above this level for the SRB and the SLB, and the difference was significant. In the SJB, levels above 10 nmol/l were reached on days 161-180 of gestation. In the second part of this study the levels of oestrone sulphate were measured around parturition in SRB cows. At parturition, the levels of oestrone sulphate rose to peak values of 79.9 +/- 5.2 nmol/l and then decreased to 6.6 +/- 0.5 nmol/l on the day after calving. In one cow peak values of 66.0 nmol/l were reached 2 days prior to parturition, and subsequently dropped to 7.0 nmol/l at parturition. This cow had retained foetal membranes. A possible relationship between low oestrone sulphate levels prior to parturition and retained foetal membranes is discussed.     

ORIGINAL ARTICLE: Effects of ambient temperature and soybean meal supplementation on intake and digestion of two sheep breeds differing in mature size

The aim of this study was to compare the intake and digestive physiology of mature ewes of two breeds ? Ile‐de‐France (mature weight: 75–80 kg) and Churra‐da‐Terra‐Quente (CTQ; mature weight: 45–50 kg) ? and evaluate the effects of ambient temperature and protein supplementation in the comparison. The temperature (25 °C vs. 11 °C) and soybean meal supplementation (150 g/kg of ingested hay on dry matter basis vs. unsupplemented control) were evaluated in 48 adult ewes of two breeds fed hay ad libitum and at a restricted level of intake. The intake, digestibility, rumen pH and NH₃–N, rumen outflow rates, faeces particle size and thyroid hormones levels were measured. These hormones can be related with gastrointestinal motility, thus explaining rumen outflow rate patterns. Dry matter intake per kg of body weight was higher in CTQ ewes (p < 0.05). This breed also exhibited lower organic matter and neutral detergent fibre digestibility (p < 0.001) and higher solid (p < 0.001) and liquid (p < 0.01) rumen outflow rates irrespective of intake level, supplementation or temperature. Rumen pH remained above 6.6 in all treatments. NH₃–N rumen content was similar (p > 0.05) when breeds were fed only hay. There was no breed effect (p > 0.05) on faeces particle size. Triiodothyronine was not affected (p > 0.05) by breed and thyroxine was higher (p < 0.10) in the CTQ breed but only at the lower temperatures (breed × temperature, p < 0.05). Ile‐de‐France sheep showed a lack of adaptation to lower temperatures. This study suggests that the native CTQ breed fulfils its metabolic needs by having a higher intake and inherits faster flow through the gastrointestinal tract, as a result, its digestive ability is diminished.     

Effect of birth weight,gender and litter characteristics on summer mortality in lambs of Norwegian breeds

Abstract

This study describes how birth weight, gender, litter size, and age of dam affect lamb mortality during the summer period, using data on lambs of the breeds Spælsau (N ≈ 110 000) and Norwegian White Sheep (N ≈ 450 000) during 1994 to 2005. A general mixed linear model was used for the analysis. Birth weight affected summer mortality non-proportionally: an increase in weight from very small towards the breed mean strongly deflated mortality risk; weigh increase above breed means had little effect. Male lambs had a higher mortality than females, and lambs born by 12-months-old dams were in greater risk than those having older dams. Increasing litter size resulted in increased mortality. The results are discussed and recommendations for future research, with focus on breeding and genotype by environment interaction effects are made.     

Toxoplasmosis in sheep,goats and cattle in central Ethiopia

In a seroepidemiological survey using an indirect haemagglutination assay, the prevalence rate of toxoplasmosis in central Ethiopia was 22.9% of 899 sheep, 11.6% of 753 goats and 6.6% of 785 cattle. There were high titres of 1:256 or more which suggest current infections. These results indicate that toxoplasmosis may be an important cause of reproductive wastage in small ruminants. The public health significance of this disease is discussed. Improved hygiene and management could reduce the prevalence of the disease.     

Summer Variation in the Concentration of Steroidal Sapogenins in and the Degree of Fungal Infection on Narthecium ossifragum plants from Møre og Romsdal County,Norway

Thirty-nine leaf samples ofNarthecium ossifragum collected from eight sites in More og Romsdal County, Norway, during June–September 1997 and 41 leaf samples collected at five sites in the same county during June–August 1998 were analysed for the concentrations of steroidal sapogenins using GC-MS. The 1998 samples were also examined for fungal elements (conidia and hyphae) after incubation in a moist chamber for 10–14 days. The highest 1997 and 1998 leaf sapogenin concentrations (4881 and 7115 mg/kg dry matter, respectively) were 13–14 times greater than the lowest sapogenin concentrations found (344 and 531 mg/kg dry matter, respectively). The results did not reveal systematic differences in sapogenin concentrations between the two seasons, or between samples harvested early or late in the same seasons, or between sapogenin concentrations in plants harvested at different sites.Cladosporium magnusianum was the predominant fungus found in the samples. The degree of fungal infection on the samples was in generally low, but the number ofC. magnusianum colonies in the moist chamber preparations and fungal elements (conidia and hyphae) in leaf washings and on leaves tended to increase with time. Factor analysis and multiple regression analysis performed on the chemical and fungal results suggest that sporulation may have occurred in the fungi in response to increase in sapogenin concentrations.     

The effects of experimentally induced fever on the estimated blood flow to and oxygen utilization by the liver and the viscera drained by the portal vein in sheep

Intrajugular injection of a purified E. coli lipopolysaccharide induced a biphasic fever in sheep after a latent period of 12 to 20 min. The changes in the blood flow from the liver and from the viscera drained by the portal vein were: (a) in the latent period, decreases in total hepatic blood flow (THF) due to decreased portal venous blood flow (PVF); (b) during the first febrile phase, increases in THF due to increased hepatic arterial blood flow and, (c) in the second febrile phase, increases in THF due to decreased PVF. Although there were large variations in the oxygen supply to the viscera drained by the portal vein and to the liver, there were relatively small or no changes in their oxygen consumption.     

Looking for prognosticators in ovine anaplasmosis: discriminant analysis of clinical and haematological parameters in lambs belonging to differently susceptible breeds experimentally infected with Anaplasma ovis

Background

A study was carried out to evaluate the response of different native sheep breeds to experimental infection with Anaplasma ovis, the most prevalent sheep tick-borne pathogen in Apulia (Southern Italy). Thirty-four lambs belonging to a Northern European breed (Suffolk) and two Southern Italian breeds (Comisana and Altamurana) were infected. Eleven clinical as well as haematological parameters were monitored at different temporal resolutions on the same subjects before and after the infection, resulting in a data set of 435 observations. The present work, aiming to further the research, presents the results of a multivariate analysis carried out to identify which parameters out of the eleven considered are the most reliable parameters to be considered as markers of the disease phenotype as well as prognosticators of practical clinical importance.

Results

Data were analysed by discriminant analysis. Out of the eleven considered variables (red blood cells, packed cell volume, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin content, haemoglobin concentration, white blood cells, neutrophils, leukocytes, platelets, rectal temperature), only seven were included in the step-wise model since significantly increasing the Mahlanobis distance between the two closest groups. Both discriminant functions resulted to be highly significant (P < 0.0001) and the percentage of variation accounted for by the first discriminant function was 63.6% of the variance in the grouping variable.

Conclusions

Taken together, the observed results stress the marked differentiation among the three breeds in terms of physio-pathological phenotypes indicating packed cell volume and red blood cell count as the most informative parameters in the routine clinical practice for A. ovis infection in sheep.     

Accumulation of Sapogenin Conjugates and Histological Changes in the Liver and Kidneys of Lambs Suffering from Alveld,a Hepatogenous Photosensitization Disease of Sheep Grazing Narthecium ossifragum

Sixteen lambs exhibiting hepatogenous photosensitization (alveld) after grazing pasture containing Narthecium ossifragum and seven nonphotosensitized lambs grazing the same pastures were studied. All the alveld-affected lambs revealed liver damage dominated by single cell necrosis, portal fibroplasia and bile duct proliferation. Crystalloid clefts were demonstrated in the bile ducts of two and in the hepatocytes and Kupffer cells of nine photosensitized lambs. Plasma bilirubin concentration was severely increased in ten of the cases of alveld whereas the activity of aspartate aminotransferase was moderately to severely increased in seven cases. The activity of glutamate dehydrogenase was moderately elevated in one of the photosensitized lambs. The main histopathological findings in the kidneys from the alveld-affected lambs were dilated tubules, often with eosinophilic material in the tubular lumina. Regenerative changes were seen in a large proportion of the renal sections. Elevated plasma concentrations of urea and creatinine, and the renal histopathological changes, suggested that the photosensitized lambs had been through a phase of renal injury. Analysis of the free and conjugated sapogenin content in liver tissue and bile was performed by gas chromatography–mass spectrometry. There were significantly higher concentrations of conjugated episapogenins in both the liver and bile in the alveld-affected lambs than in the nonphotosensitized lambs.     

The distribution pattern of Sarcocystis species,their transmission and pathogenesis in sheep in Fars Province of Iran

Of 1362 sheep examined during two years in Fars Province of Iran, 786 (57.7%) were positive for Sarcocystis spp. The prevalence was significantly higher (p<0.05) in animals owned by nomadic Assyrians (67.95%) than in those owned by local people (41.86%). More of the animals above 2 years age were infected (69.98%) than young ones (30.02%). Females had a higher prevalence of infection (61.07%) than males (38.93%) but most of the males were younger. There was no variation in the infection rate during spring, summer or autumn, but it was low in winter. The species observed were Sarcocystis gigantea, predominantly in oesophagus, S. medusiformis, mainly in diaphragm, S. tenella in the oesophagus, diaphragm, tongue and heart, and S. arieticanis in the oesophagus, tongue and occasionally in the diaphragm. In transmission studies, the prepatent period for S. gigantea and S. medusiformis and for the two microscopic species was 11–13, 10 and 8–12 days, respectively. The infection could not be transmitted to hamsters and guinea-pigs. The macroscopic species were almost non-pathogenic but were responsible for economic losses because of rejection of carcases or parts thereof at slaughter. The microscopic species caused tissue damage to the affected organs, resulting in haemorrhages, mononuclear infiltration and necrotic changes.Abbreviations DPI days post infection     

Pharmacokinetics of Ricobendazole After its Intravenous,Intraruminal and Subcutaneous Administration in Sheep

Ricobendazole (RBZ) was administered in sheep at the dose rate of 5 mg/kg by intravenous (i.v.) route as a 10% experimental solution, by the intraruminal (i.r.) route as a 10% experimental suspension, and by the subcutaneous (s.c.) route as a 10% commercial formulation available in Argentina. Blood samples were drawn during a 60 h period. Plasma concentrations of RBZ and its inactive metabolite albendazole sulphone (ABZSO₂) were determined by high-performance liquid chromatography. The pharmacokinetic parameters were determined by compartmental analysis. The fitting of the data was done by weighted least-squares non-linear regression analysis. The pharmacokinetic parameters were estimated for every animal by simultaneous fitting of the plasma concentrations profiles of RBZ obtained after its administration by the three routes. The kinetic analysis of ABZSO₂ was performed by a statistical moment approach. Ricobendazole bioavailability was poor after i.r. administration, whereas high and sustained plasma concentrations and higher bioavailability were obtained after s.c. administration. A simple two-compartment open model explains in a mechanical sense the pharmacokinetic behaviour of RBZ in sheep and allows us to estimate the real first-order constant rate of absorption and the loss of drug from the absorption site after its administration by s.c. and i.r. routes.     

Helminths of sheep and goats in desert areas of south-west Mauritania (Trarza)

Faecal samples were obtained from sheep and goats before, during and after the rainy season at three locations in south-west Mauritania. Several animals were also necropsied at the same time.Haemonchus contortus was the most prevalent worm. Infection by digestive-tract strongyles andStrongyloides papillosus was always very light (prevalence less than 20%). Sheep were more heavily infected than goats but animals under 1 year of age were not infected by digestive-tract strongyles. It is likely that young small ruminants became infected during the rainy season and that the parasites so acquired are inhibited in their development and/or survive nearly one year as adults.     

Prevalence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from Mossoró, Rio Grande do Norte, Brazil

Toxoplasma gondii is an obligate intracellular parasite with a variety of hosts, responsible for reproductive problems and economic losses in sheep flocks. Neospora caninum was recently identified and its clinical presentation in sheep is similar to that of toxoplasmosis, which can cause repeated abortions, though less frequently in this species. In order to confirm the prevalence of these agents in the city of Mossoró, Rio Grande do Norte, Brazil, 409 serum samples from adult sheep (364 females and 45 males) were tested by the indirect immunofluorescence antibody test, using cut-off point at a dilution of 1:64 and 1:50 for T. gondii and N. caninum, respectively. From the 35 properties examined, 23 (65.7%) had at least one seropositive animal for T. gondii and six (17.1%) for N. caninum. The prevalence of seropositive animals for T. gondii was 20.7% and for N. caninum 1.8%. There was no association between the presence of the agent’s antibody and gender, reports of reproductive problems and presence of dogs and/or cats in the properties. T. gondii is well distributed and N. caninum has low prevalence in sheep and in the properties of the studied region.     

The stability of glutathione peroxidase activity in plasma from cattle,pigs and sheep on storage in the presence and absence of glutathione

Ovine, bovine and porcine plasma glutathione peroxidase (GSH-Px) activity decreased on storage at both 4°C and 20°C. The ovine and bovine enzymes were significantly less stable than the porcine enzyme. The addition of GSH to a final concentration of 2 mmol/L to plasma samples at the commencement of storage retarded the loss of both ovine and bovine plasma GSH-Px activity. The ovine enzyme was unique in that after inactivation by storage at 4°C, incubation with GSH restored the enzyme activity. It is recommended that plasma GSH-Px should be assayed fresh, or otherwise stored at –20°C.