Epidemiology of sheep myiases in São Paulo State, Brazil

A survey of Diptera species causing cutaneous myiases on sheep in Botucatu, São Paulo, Brazil was made to determine seasonal incidence, predilection sites and the factors predisposing to infestation. Sheep were checked daily for myiases for one year. At two week intervals larvae from wounds were collected for identification. Only larvae of Dermatobia hominis and Cochliomyia hominivorax were found. Myiases due to C. hominivorax were observed during the whole year with high incidence from January to April. The feet, vulva, tail and scrotum were most frequently infested. Wounds were the commonest predisposing factor. © 1992 Centre for Tropical Veterinary Medicine, University of Edinburgh.

Effect of air temperature and humidity on ingestive behaviour of sheep

Thirty-two Polwarth ewes, of ages up to 1 year, were observed in a climatic chamber (24 to 45° C) for eight periods of 5 h each. The observations were made through a window in the chamber wall. All animals were observed four times, then shorn and observed four times again. The animals were given weighed quantities of water and feed consisting of commercial concentrate plus Rhodes grass (Chloris gayana) hay. The water and feed remaining after 5 h of observation were weighed. The following traits were analysed: time eating hay (TEH), time eating concentrate (TEC), time drinking water (TDW), weight of hay eaten (WHE), weight of concentrate eaten (WCE), volume of ingested water (VIW), ruminating time standing up (RTS), ruminating time lying down (RTL), idling time standing up (ITS), and idling time lying down (ITL). Shearing had a significant effect for all traits except ITS. Shearing resulted in higher values for all traits except for ITS and ITL. Ingestion of hay (TEH and WHE) decreased with increased air temperature and humidity, while the ingestion of concentrate (TEC) and WHE) and water (TDW and VIW) increased. Rumination decreased with increased air temperature and humidity, and was higher in shorn than in unshorn sheep. © 1992 International Society of Biometeorology.

Influence of hot environments on some blood variables of sheep

Thirty-two Polwarth sheep of ages up to 1 year were observed under temperatures varying from 10.5 to 46.5°C. The following blood cell counts were made: erythrocyte (RBC), leucocyte (WBC), eosinophil (EOS), neutrophil (NEU), lymphocyte (LYM) and monocyte (MON). Other traits measured were: haemoglobin (HB), haematocrit (HT), blood glucose (GLU) and serum protein (PROT). Multivariate analysis of variance was used and the results showed a significant (P<0.001) effect for the interaction of shearing and temperature treatment. Under temperatures >25°C, sheep presented a decrease of RBC, WBC, HB and HT, these differences being greater in the shorn than in the unshorn animals. Unshorn animals presented higher variations in EOS, NEU, LYM, MON and GLU. Blood glucose increased under high temperatures in the shorn animals (from 56.36±0.65 mg/100 ml to 60.52±0.69 mg/100 ml) as in the unshorn animals (from 54.72±0.74 mg/100 ml to 57.56±0.77 mg/100 ml). © 1992 International Society of Biometeorology.

Optic neuropathy in sheep associated with overdosage of closantel

This report describes clinical and pathological findings in 2 flocks in Brazil where blindness and deaths in sheep occurred after closantel overdosage. Depression, weakness, and blindness affected 37 animals and 17 died in 2 flocks of 190 animals. Two animals submitted for ophthalmic examination showed no inflammation in the anterior segment of both eyes; posterior segment evaluation by indirect ophthalmoscopy suggested retinal degeneration. One postmortem evaluation local spongy vacuolization was in several regions of the brain and the optical nerves had severe axonal degeneration.

Synaptonemal complex analysis of Nellore and Gyr breeds of Bos taurus indicus

A synaptonemal complex (SC) study of specimens of Nellore and Gyr breeds of Bos taurus indicus was performed with the main objective to identify and determinate the frequency of abnormalities of SC and the frequency of cells with abnormalities. All animals analyzed had 29 autosomal bivalents and one sexual bivalent. The Nellore breed had 30.00% of cells with SC abnormalities while the Gyr breed had only 11.11%. Statistical analyses showed that there were not significant differences for the number of cells with abnormalities among the breeds studied. The subspecies Bos taurus indicus had 16.92% of cells showing abnormalities, being 62.82% of these abnormalities in zygotene and 37.18% in pachytene. Some aspects regarding the frequency of cells with abnormalities and the fertility of Nellore and Gyr breeds are discussed.

Características anátomo-estruturais da pelé de ovinos (ovis áries L.) lanados e deslanados, relacionadas com o aspecto físico-mecânico do couro

The objective of the study was establishing the anatomical-structural differences between the skin of non-wool sheep of the Morada Nova breed and wool-on sheep of the Polwarth or Ideal breeds and their relations to the physical-mechanical characteristics of their leather after tanning. Ten animals of both breeds were used, with five animals of approximately one and four years of age of each breed. The animals were slaughtered, and immediately after skinning, samples were taken viewing the microtomy of the skin in the dorsal, lateral, ventral, hind and palette regions, parallel and perpendicular to the head-tail axle, and perpendicular to the grain of the skin. The skins were depilated, chromium-tanned and re-tanned. From the leather, three samples were taken from the two directions considered from the regions studied for physical-mechanical analysis, for tension and tear resistance and distension on the lastometer. The average of the results of the physical-mechanical analysis were compared by Tukey test at the levels of 1 and 5% probability. The breed, the age, the region and the position exerted a positive effect on the values of the resistance of the leather to tension for the Morada Nova four year old sheep, reaching a minimum of 200 kg/cm . The region and the position exerted a positive effect on the values of tear-resistence of the leather for both breeds studied, reaching a minimum of 40 kg/cm. The resistance of the leather on distension was superior to 8 mm, for all the animals studied, not influenced by breed, age, region or position. The skin of the Ideal sheep presented a thermostatic skin layer greater than the reticular layer with great folicular and glandular density, contrary to the skin of the Morada Nova sheep where the thermostatic and reticular layers are of approximately the same thickness, with less folicular and glandular density.

Biological control of sheep parasite nematodes by nematode-trapping fungi: In vitro activity and after passage through the gastrointestinal tract

The main method used for the control of gastrointestinal nematodes in sheep production is the application of chemotherapeutic agents, which often lead to the selection of parasites resistant to given active principles. Biological control can be considered a promising alternative, contributing to an increase in the efficacy of verminous control. We determined the in vitro activity and in situ survival of the predatory fungi Arthrobotrys musiformis and Arthrobotrys conoides during passage through the gastrointestinal tract of sheep after oral administration of conidia in microencapsulated form and as a liquid in natura. Initial in vitro tests showed that both fungi were efficient in the predation of trichostrongylid L3 larvae present in the faeces of sheep naturally infected with gastrointestinal nematodes. The fungi presented high nematophagous activity, which was 99.3% for A. conoides and 73.7% for A. musiformis. A. conoides did not survive passage through the gastrointestinal tract under the conditions of the present experiment. On the other hand, A. musiformis was reisolated after administration in either microencapsulated or liquid form, suggesting that this species is a promising alternative for the control of nematodes in sheep since it survives without any protection (in natura). © Springer 2005.

Efficacy of homeopathic treatment against natural infection of sheep by gastrointestinal nematodes.

The efficacy of the homeopathic treatment with the Fator Vermes, administered according to the manufacturer's recommendations, was evaluated against gastrointestinal nematodes infections in sheep. The experiment was divided into two phases: in the first phase (January/06/2004 to April/30/2004), the animals of the treated (n=10) and control (n=10) groups were treated individually with conventional anthelmintics to avoid deaths. In the second phase (April/30/2004 to July/06/2004), the sheep from the group that received the Fator Vermes were treated as they had been in the previous phase, while the control group animals were treated with conventional anthelmintics at 14 day intervals. In the first phase of the experiment, there was no significant difference (P>0.05) between group means regarding egg counts in feces (EPG), weight gain, or packed cell volume (PCV). Meanwhile, in the second phase, the control group sheep had a significantly higher weight gain, higher PCV values, and lower EPG counts. Infective larvae of Haemonchus spp., Trichostrongylus spp., Cooperia spp., and Oesophagostomum spp. were identified in the fecal cultures. After six months of daily treatment with the Fator Vermes, it was not possible to substantiate the product's benefits in both sheep health and productivity or in the prophylaxis of gastrointestinal nematode infections.

Sheep and cattle grazing alternately: Nematode parasitism and pasture decontamination

Three grazing management systems were compared to examine pasture decontamination of gastrointestinal nematode parasites (GIN) of sheep (Ovies aries) and cattle (Bos taurus). They consisted of sheep and cattle grazing paddocks alternately for 32, 96 or 192 days over 2 years. Pastureland (8.43 ha) was subdivided into six areas of eight paddocks each to produce an eight-paddock rotational grazing system. Every paddock was grazed for 4 days and then rested for 28 days. Sixty-six Ile de France ewes and 12 steers were randomly divided into three groups (22 sheep and four cattle per group). Each grazing system included a cattle area and a sheep area. Sheep and cattle interchanged areas every 32 days in system 1 (Group 1), every 96 days in system 2 (Group 2) and every 192 days in system 3 (Group 3). Fecal examination and larvae counting on pasture were performed every 32 days. During summer, winter and spring 2005, tracer lambs free of nematode infection were introduced into each sheep group and later sacrificed for quantification and identification of GIN species. All cattle were sacrificed for the same purpose. The main parasites found in tracer lambs were Haemonchus contortus and Trichostrongylus colubriformis, and in cattle, Haemonchus similis, Cooperia punctata and Oesophagostomum radiatum. Pasture contamination by sheep-infective GIN larvae was considerably reduced after 96 or 192 days of cattle grazing. Cross-infections between sheep and cattle GIN were not significant, which suggested that integrated grazing using such animals could be used for pasture decontamination. However, as effective anthelmintics were not available, decontamination was not sufficient for proper prophylaxis of GIN infections in Ile de France sheep, which are quite susceptible to such parasites. © 2007 Elsevier B.V. All rights reserved.

Semen variables of sheep (Ovis aries) experimentally infected with Toxoplasma gondii

The influence of Toxoplasma gondii on semen variables and sperm morphology of sheep was evaluated in eight reproductive males distributed into three experimental groups: GI, three sheep inoculated with 2.0 × 105 of P strain oocytes; GII, three sheep infected with 1.0 × 106 of RH strain tachyzoites and; GIII two control sheep. Clinical (rectal temperature, cardiac and respiratory frequencies), parasite and serology exams (IIF) were realized. Sperm variables (volume, motility, vigor and concentration) and semen morphology for each sheep were also evaluated. Thus, semen and blood collections were assessed on post-inoculation days (PIDs)-1,3,5,7,11,14 and weekly thereafter up to PID 70. Clinical alterations were observed (hypothermia and anorexia) in infected sheep from groups GI and GII. Parasitic outbreaks were detected in five sheep. All the infected sheep produced antibodies against T. gondii from PID 5 onwards, reaching a peak of 4096 and 8192 for group GI and GII sheep, respectively. Differences (P < 0.05) were observed regarding the ejaculate volume between the inoculated groups (oocytes and tachyzoites) and control. Even though experimental toxoplasmic infection resulted in clinical symptomology in the inoculated sheep, the minimal alterations in sperm pathologies could not be directly attributed to T. gondii. © 2008 Elsevier B.V. All rights reserved.

Ultrastructure of sheep primordial follicles cultured in the presence of indol acetic acid, EGF, and FSH

The aim of this study was to investigate the ultrastructural characteristics of primordial follicles after culturing of sheep ovarian cortical slices in the presence of indol acetic acid (IAA), Epidermal Growth Factor (EGF), and FSH. To evaluate ultrastructure of primordial follicles cultured in MEM (control) or in MEM containing IAA, EGF, and FSH, fragments of cultured tissue were processes for transmission electron microscopy. Except in the control, primordial follicles cultured in supplemented media for 6d were ultrastructurally normal. They had oocyte with intact nucleus and the cytoplasm contained heterogeneous-sized lipid droplets and numerous round or elongated mitochondria with intact parallel cristae were observed. Rough endoplasmic reticulum (RER) was rarely found. The granulosa cells cytoplasm contained a great number of mitochondria and abundant RER. In conclusion, the presence of IAA, EGF, and FSH helped to maintain ultrastructural integrity of sheep primordial follicles cultured in vitro. © 2011 Evelyn Rabelo Andrade et al.

Effect of percutaneous transthoracic lung biopsy on oxidative metabolism in sheep

This study aimed to assess the effect of percutaneous transthoracic lung biopsy on the oxidative metabolism of sheep by measuring the oxidative stress markers of superoxide dismutase (SOD), total glutathione (GSH-t), peroxidase (GSH-Px) and thiobarbituric acid reactive substances (TBARS) in the red cells of these animals. Blood samples were collected from 20 clinically healthy sheep prior to, and 30 min after, percutaneous transthoracic lung biopsy. After biopsy, there was a significant decrease (p < 0.05) in SOD and GSH-Px activity, with no significant change (p ≥ 0.05) in GSH-t and TBARS concentrations. These results showed that percutaneous transthoracic lung biopsy did not significantly affect the oxidative metabolism of sheep 30 min after the procedure, which may be used widely in this species without causing serious tissue damage. © 2012. The Authors.

Differentially transcribed genes in skeletal muscle of lambs

The objective of this study was to compare gene transcription profiles in Longissimus dorsi muscle of the following four hair sheep genetic groups, Morada Nova (MO), Brazilian Somali (SO), Santa Inĉs (SI) and 1/2 Dorper×1/2 Morada Nova (F1). These groups all display different postnatal muscle growth. The transcriptomes of the skeletal muscle of the lambs (at 200 days of age) were profiled by using oligonucleotide microarrays and reverse transcription-quantitative real-time PCR (RT-qPCR). The microarray experiment identified 262 transcripts that were differentially expressed when transcription levels were compared between the different breeds. A total of 23 transcripts among which those involved in skeletal muscle development (MyoD1 and IGFBP4), lipogenesis and adipogenesis (C/EBPδ, PPARγ and PGDS) were differentially expressed in at least in one comparison. Clustering analysis showed that there is greater similarity in gene expression between the MO and SI breeds and between F1 and SO genetic groups. The SO breed has the most distinct expression pattern. The RT-qPCR results confirmed the findings from the microarray study. A positive correlation was observed between the expression of MyoD1 and the cold carcass yield. The negative correlations between the weight and yield of cold carcass with the expression of C/EBPδ mean that the selection for adipogenesis could lead to a lower carcass weight. The GLUT3 and PYGL gene transcripts were negatively correlated with fat thickness, but ATP5G1 was positively correlated with this trait. Interestingly, many genes negatively correlated with PUFA were positively correlated with cold carcass yield. In conclusion, the present work demonstrated that there are breed-specific expression patterns in Brazilian hair sheep genetic groups. The differences in gene expression among genetic groups were consistent with their phenotypic differences. The positive correlation of the MyoD1 expression with the cold carcass yield suggests that this gene is important for tissue growth in sheep. The positive correlation of the C/EBPδ expression with PUFA provides an opportunity to select for lipid deposition in meat animals. © 2012 Elsevier B.V.

Supplementation of diets for Santa Ines sheep with organic and inorganic zinc sources

This research was conducted with objective to evaluate the effect of different zinc (Zn) sources and doses in the diet for Santa Ines sheep. Forty lambs at weaning, with 18.4 kg of body weight were supplemented with three different sources of zinc (zinc oxide (ZnO), zinc amino acid and zinc proteinate) and three doses of zinc (200, 400 and 600 mg/kg DM) added to the basal diet. At every 28 days, animals were weighted and blood samples were collected for analyses of zinc (Zn), alkaline phosphatase and immunoglobulin G (IgG) and M (IgM). At the end of experiment, liver samples were collected for determination of the hepatic zinc levels. Zinc was analyzed with atomic absorption spectrophotometer, while phosphatase alkaline and immunoglobulins G and M were analyzed using Laborlab and Bioclin kits, respectively. There was no effect of diets on phosphatase alkaline levels and hepatic zinc, but there was difference in the plasmatic zinc levels and IgG and IgM levels. Based on the accumulation of hepatic zinc, the estimate of the zinc bioavailability, through the regression equation, showed that supplementation with organic and inorganic sources of zinc did not differ in the diet of Santa Ines sheep. © 2012 Sociedade Brasileira de Zootecnia.

Effect of roscovitine and cycloheximide on ultrastructure of sheep oocytes

It is believed the temporary meiosis arrest with roscovitine or cycloheximide may improve the in vitro developmental competence of oocytes in different animal species. However, little is known about the effects of these inhibitors on ultrastructure of ovines cumulus-oocyte complexes (COCs). The aim of this study was to evaluate the progression of cytoplasmic maturation and the ultrastructural changes in sheep COCs exposed to roscovitine or cycloheximide, at acceptable concentrations. COCs were in vitro cultured for 24. h in maturation medium (control group) containing 100 μM roscovitine or 1 μg/mL cycloheximide (treatment groups). After this time, some COCs were cultured for further 22. h in inhibitor-free medium. The ultrastructure organization of COCs was evaluated by transmission electron microscopy before (immature group) and after in vitro culture for 24 and 46. h. As expected, signs of immaturity and maturity were observed in immature and control groups, respectively. In treatment with roscovitine, there were cumulus cells degeneration, swelling of mitochondrias, few cortical granules and many vesicles with electron-dense material. However, in cycloheximide treatment there were not signs of degeneration or cellular senescence. Metabolic units and mitochondrial pleomorphism were found in all experimental groups. These evidences demonstrate that roscovitine promoted irreversible ultrastructural changes while cycloheximide did not affect the cytoplasmic maturation. However, the implications on embryo development are still unclear. © 2012 Elsevier B.V.