Sheep Heads Research Articles

Range-uncertainty imaging for obtaining dose perturbations in proton therapy

The proton dose distribution of a monoenergetic parallel proton beam in a biological sample (a sheep head in a mold) has been calculated using a Monte Carlo code. The calculations have been performed both including the effect of multiple Coulomb scattering of the protons at the atoms in the phantom and without it. The resulting dose distributions were subtracted from each other and their absolute value was integrated in the direction of the incident proton beam. This projected dose difference was compared to measurements of proton range uncertainties obtained using proton radiography data. A nearly linear relationship between the dose perturbations and the range variations was found which indicates that measured range variations can be used to predict dose perturbations in proton therapy.

Effect of abdominal vibroacoustic stimulation on sound and acceleration levels at the head of the fetal sheep

To measure the vibratory response of the fetal head and abdominal wall in sheep during vibroacoustic stimulation. A piezoresistive accelerometer was attached to the skulls of seven sheep fetuses (128-134 days' gestational age), and a miniature hydrophone was attached to the skin overlying the fetal temporal bone. During fetal preparation and vibroacoustic stimulation procedures, ewes were anesthetized and supine. Vibroacoustic stimulation of the maternal abdomen was produced by each of two clinical devices that differed in spectral content, and an electric toothbrush. The approximate fundamental frequencies (f0) and first overtones (f1), as determined by both recordings of intrauterine sound pressure level and fetal head acceleration, were as follows: fetal acoustic stimulator, 75 and 150 Hz; electronic larynx, 150 and 300 Hz; and electric toothbrush, 25 and 50 Hz, respectively. At fundamental frequencies and first overtones, the ranges of fetal head accelerations (expressed in 1/12-octave bands) were as follows: fetal acoustic stimulator, 10-53 and 25-224 mm/sec2; electronic larynx, 10-53 and 18-114 mm/sec2; and electric toothbrush, 33-792 and 8-116 mm/sec2, respectively. Sound pressure levels exceeded 110 dB in all cases. High sound pressure levels in the uterus were proportional to fetal head vibration levels. Vibroacoustic stimulation of the surface of the abdomen of pregnant sheep is accompanied by both acoustic and vibratory exposure of the fetus.

Government fiscal policy in mandatory Palestine in the 1930s

The fiscal system of Palestine under Ottoman rule was divided into two: the autonomous Sanjaq, or District of Jerusalem, came under the direct control of the Ministry of Finance at Constantinople, whilst the Sanjaqs of Acre and Nablus were administered from Beirut.' There were three direct rural taxes: the Werko, the Tithe, and the Animal Tax. The Werko rate was 4 per mille of the capital value of Miri, or State Land, as it had been assessed 25 years previously; the Tithe was collected at 12.5 per cent rather than 10 per cent on the gross yield of the land; and the Animal Tax was a tax per head of sheep, goat or pig, and those camels and buffaloes not used for ploughing.2 With time, large estates had been formed in Ottoman Palestine through the farming out of tax-collection. Here, the collection of tax especially meant the 'ushr tax, or the yearly tithe due on agricultural land.3 Taxcollection was farmed out for short periods in exchange for large payments to the government. The 12.5 per cent tithe of gross yield was a heavy burden for the peasantry as it translated to approximately 35 per cent of the net yield which rarely exceeded the minimum subsistence needs of the fellah,4 who was already at the mercy of the tax-collector. Partly to cover his own costs, and partly to make a gain, the multazim, or tax-collector, often exacted over half of the peasant's produce and so:

Small ruminant production in Lebanon's Beka'a Valley

A formal survey was conducted in 1993 to identify small ruminant production systems and constraints in the Beka'a Valley of Lebanon. Cluster analysis revealed three basic production systems. Cluster 1 consisted of medium size (200 head) sedentary village flocks comprised of > 70% sheep with rangelands supplying less than 20% of their annual diet. Cluster 2 consisted of large migratory flocks (400 head) of sheep and goats in roughly equal numbers. The flocks owned by landless farmers made heavy use of rangelands (> 45% of annual diet). Cluster 3, with medium size (200 head) mixed flocks, made moderate use of rangelands, 30% of annual diet. The results indicated seasonality in production components and low productivity in all three clusters. Supplemental feeding and grazing reflected differences in feed sources used among clusters. Hand-feeding, however, accounted for 85% of diets between December and March. Small ruminant production contributed an average of 70% of farmers' income in all clusters, supplemented by off-farm activities (19%) and crop production (11%). Farmers' perception of the major constraints to sheep and goat productivity were similar among clusters. They include: (1) health problems, namely infective diseases and parasites, and lack of veterinary services, (2) feed availability, in particular expensive feed supplements, (3) poor marketing of animal products. Future research is needed in the following fields: (1) full-screening of all diseases to develop an adequate health program, (2) on-farm feeding trials to optimize feeding systems, (3) range and grazing research to determine proper stocking rates and season of use, (4) bioeconomic analysis and marketing research to asses the future viability of the small ruminant sector.

An animal model for training in endoscopic nasal and sinus surgery.

An animal model has been devised to allow trainees in nasal and sinus endoscopy to develop basic instrument handling and psychomotor skills, without risk to patients. The sheep's head obtained from the abattoir was modified slightly to simulate more closely the human situation. The model permits nasendoscopy, foreign body removal, septoplasty, turbinate reduction, frontal and maxillary sinoscopy, antrostomy and an epistaxis exercise. To date the tissues have been used freshly thawed, and must be used on the day of preparation.

The Macroanatomic Study on Terminal Branches of the External Jugular Vein in Akkaraman Sheep

Ten heads of akkaraman sheep of different sex were used. Latex was injected through the external jugular vein for investigation purposes. The following was determined: Ventral cerebral vein arises from the external jugular vein and it anastomoses with the emissary vein of the jugular foramen. The dorsal cerebral vein enteres the temporal meatus and originates from the superficial temporal vein. The linguofacial vein arisis from the external jugular vein. The lingual vein takes its origin from the linguofacial vein the Pterygoid plexus consisted of several anatomotic veins located between the pterygoid muscles the venous drainage of the nasal mucosa is mainly via the sphenopalatina vein.

A REPORT ON THE COMPARATIVE RESPONSE OF SHEEP EPIDERMAL SQUAMOUS-CELL CARCINOMA TO INTRAARTERIAL VERSUS INTRAVENOUS CISPLATIN INFUSION

There is an apparent lack of randomised clinical trials demonstrating a therapeutic advantage for intra-arterial, versus systemic, cisplatin administration as cancer treatment. A spontaneous, head and neck epidermal squamous cell carcinoma in sheep was used to compare intra-arterial and equivalent dose intravenous cisplatin infusion. The objective response rate for intra-arterially infused lesions was 73%, with a mean tumour regression for all carcinomas of 70% +/- 6 (sem). In comparison, 27% of intravenously treated carcinomas showed an objective response, the mean volume reduction being 42% +/- 6 (sem). Statistical comparison of the number of objective response lesions was significantly in favour of intra-arterial cisplatin therapy (p<0.05), as was the difference in the mean tumour response for both groups (p<0.005). The experimental data suggest that further study of the clinical application of intra-arterial induction cisplatin therapy is warranted.

Proton radiography as a tool for quality control in proton therapy.

Proton radiography is investigated for its use as a quality control tool in proton therapy. Images were produced both with range and range uncertainty information of protons passing through phantoms (Alderson phantom and a sheep's head). With the range images the correct positioning of the patient with respect to the beam could be verified. The range uncertainty images were used to quantitatively detect range variations of protons passing through inhomogeneities in the patient. These measurements can be used to indicate critical situations during proton therapy or to determine the safety margin around the tumor volume. With the range information the precision of different calibrations of computer tomography Hounsfield values to relative proton stopping power, used for proton treatment planning, was determined. It is found that the precision in range can be improved by a detailed analysis of the calibration data obtained from tissue-substitute measurements, by a factor of 2.5. The resulting range errors are in the order of the positioning precision (approximately 1 mm).

Sound Pressure Gradients Across the Head of Fetal Sheep in Utero During Vibroacoustic Stimulation

This study was undertaken to determine if sound pressures reaching the right and left ears of the sheep fetus are equal during vibroacoustic stimulation using an electronic artificial larynx (EAL). Three ewes (one carrying twins) were sacrificed as part of other experiments. Two miniature hydrophones were fixed to skin in the left and right temporal areas of the exteriorized fetal heads. The fetal head was replaced in the uterus and aligned such that the two hydrophones were in line with the axis of stimulation and at right angles to the abdominal surface. Intrauterine sound pressure levels (SPL) from both hydrophones were compared during extraabdominal stimulation with an electronic artificial larynx. SPL at the proximal hydrophone ranged from 138-145 dB (re: 20 μPa), and were on average 17 dB greater than SPL from the distal hydrophone. One-third octave band analyses of the two hydrophone outputs revealed marked differences in frequency content. For example, differences in SPL were 19 dB at 100 Hz. 25 dB at 2,000 Hz, 34 dB at 5,000 Hz and 15 dB at 20,000 Hz. During vibroacoustic stimulation using an EAL, a significant differential in sound pressure level and frequency content reaching the right and left fetal ears may occur.

Non-biting muscidae and control methods

Many non-biting muscids (filth flies) are characterised by the habit of visiting manure or rotting organic material to feed and/or oviposit. As these flies also often have close associations with human beings, as well as human habitations and domestic animals, they are potentially both a nuisance and a contributory factor in the transmission of diseases. The authors examine the biology, economic importance and control of four of the most important non-biting muscids: housefly, Musca domestica; face fly, Musca autumnalis; Australian bush fly, Musca vetustissima; sheep head fly, Hydrotaea irritans.

Growth and body composition of Omani local sheep 1. Live-weight growth and carcass and non-carcass characteristics

AbstractForty-five local Omani ram, wether and ewe lambs were reared from birth until slaughter at 18, 28 or 38 kg live weight (five of each ‘sex’ at each weight group) on an ad libitum concentrate diet and Rhodesgrass hay.Ram lambs grew faster from birth and reached predetermined slaughter weights earlier than wether and ewe lambs. At 28 kg live weight, ram lambs had: heavier heads, feet, reticulo-rumens and livers; higher muscle and bone and lower fat proportions in the carcass; lower muscle: bone and higher muscle: fat ratios; higher proportions of carcass but lower non-carcass fat than had wether and ewe lambs. The head, feet, alimentary tract, liver and heart of Omani sheep grew at a lower rate; the skin grew at a similar rate and the carcass grew at a rate faster than empty body weight (EBW). Relative to EBW, muscle grew at a similar rate, fat faster and bone slower. Both carcass and non-carcass fats grew at a rate higher than that of the growth of EBW, with non-carcass fat growing at a higher rate than that of carcass fat. The growth rate of omental fat was the fastest followed by kidney, mesenteric, subcutaneous, tail, scrotal, intermuscular and pelvic fats respectively.This study demonstrated that Omani sheep have good potential for growth if they are managed and fed satisfactorily. Omani sheep are early maturing for which reason it is recommended that they be slaughtered at lighter weights to avoid higher fat content in the carcass. Castration in Omani sheep is not recommended for production of meat lambs under intensive systems as it resulted in reduced growth rates and deposition of excess fat at lower slaughter weights.

Controlled release insecticide devices for protection of sheep against head strike caused by Lucilia cuprina

The effectiveness of polymer matrix tags containing (w/w) 8.5% cypermethrin, 7.5% flucythrinate, 13.7% tetrachlorvinphos or 20.0% diazinon in protecting sheep against head strike by the sheep blowfly ( Lucilia cuprina Wiedemann) was investigated in larval implant, fly cage and field studies. Tags impregnated with cypermethrin reduced the total number of egg masses deposited on the heads of sheep in fly cage studies over a 6 week period by 73.3% compared with no treatment. Tags impregnated with flucythrinate reduced the number of egg masses by 25.3% over 21 weeks but there were no significant differences ( P < 0.05) between treated and untreated sheep at individual exposures. Egg masses were found on the majority of tagged sheep and no protection was provided against implants with first instar L. cuprina larvae by either cypermethrin or flucythrinate tags. Tags impregnated with diazinon gave longer protection than treatment with a liquid formulation containing 400 ppm diazinon in larval implant, fly cage and field studies. Over a 12 week period in field studies, 6.6% of rams treated with diazinon tags became struck compared with 30% treated by diazinon jetting 35.7% treated with plastic tags not impregnated with insecticide and 24.2% of untreated rams. When the rams were exposed to high populations of L. cuprina in an exposure house from 13 to 18 weeks after treatment, 3.3% of rams treated with diazinon tags, 57.1% treated by diazinon jetting, 43.8% treated with plastic tags and 23.5% of untreated rams became struck. Most strikes in the diazinon tagged sheep occurred at sites which were not contacted by the tags. Tags impregnated with tetrachlorvinphos reduced the number of strikes in comparison with no treatment in larval implant and fly cage studies but the results were inconsistent and not as good as those from diazinon tags. It is concluded that well designed controlled release devices that reliably contact the wool on the heads of sheep at sites of flystrike risk and which are able to withstand damage from rams fighting may be able to give prolonged protection against head strike.

Grasslands Advance tall fescue establishment and animal performance

Tall fescue (Festuca urundinacea Schreb.) pastures in New Zealand have been considered to have slow establishment (Grasslands Roa) or lower summer quality (the faster establishing AU Triumph). Three experiments were conducted to study the establishment vigour, herbage production and animal growth rates of a new tall fescue cultivar, Grasslands Advance. Establishment vigour of Advance was similar to that of Au Triumph and 30% greater than that of Roa. Advance and AU Triumph were 17 and 8% higher in annual grass production than Roa, with Advance significantly out yielding the other two cultivars in the warm season. Animal performance per head of young sheep on Roa was significantly higher than on AU Triumph in spring, both Advance and Roa having a significant advantage over AU Triumph in the warm season. Keywords: animal performance, Festuca arundinacae, herbage production, pasture establishment, seedling vigour

Variation in density of cattle-visiting muscid flies between Danish inland pastures.

The density of cattle-visiting flies (Muscidae) and the load of black-flies (Simulium spp.) were estimated in twelve and eighteen inland pastures in Denmark in 1984 and 1985 respectively. No differences in the geographical distribution pattern of the predominant cattle-visiting Muscidae were recorded, whilst the relative abundance and density of the species and the total fly-load varied considerably between pastures. In most cases the mean loads of Haematobia irritans (L.) and Hydrotaea irritans (Fall.) on heifers varied significantly in relation to site topography and shelter. These crude site variables explained 65-98% of the variation in densities of horn flies and sheep head flies observed between pastures. Highest densities of Hydrotaea irritans were primarily associated with permanent, low-lying, fairly sheltered grassland sites, whereas the density was low in temporary, dry, wind-exposed pastures. A comparable relationship was found for Haematobia irritans. With Haematobosca stimulans (Mg.) and Morellia spp. no relation between grassland environment and fly density was detected.

Epidemiology of Oestrus ovis in southwest France

From July 1989 to June 1990, 555 heads of adult sheep obtained from Pamiers slaughterhouse (southwest France) were examined for infestation by Oestrus ovis. Infestation was present in 65% of the heads and the mean larval burden per positive case over the year was 24.8. The monthly prevalence rate varied from 44% in April to 88.2% in November. There are usually three generations of Ovis each year: the first March–April, the second in June–July and the last in September–October. There was no fly activity in winter and during the hottest months of summer. On the other hand, nearly all the larvae overwintered as the firs stage. This study emphasizes the seriousness of the problem in the region and the authors recommend three strategic treatments per year during periods of high fly activity.

The role of Hydrotaea irritans in the transmission of summer mastitis

A series of experiments to investigate the possible role of the sheep head fly, Hydrotaea irritans, in the transmission of summer mastitis is reported. These showed that the pathogens Actinomyces pyogenes and Peptococcus indolicus may be harboured in the gut of the fly for up to 96 h following a contaminated meal; A. pyogenes survived on the surface of the fly for a similar period. H. irritans fed on the pathogens can contaminate a subsequent meal by regurgitation. However, no infections resulted from repeated exposure of the teats of heifers or cows to H. irritans fed on blood containing A. pyogenes and P. indolicus or on pus from a case of summer mastitis. In these experiments the frequency of feeding of the flies on the teat was high but subsequent bacterial contamination of the teat skin was low. Artificial contamination of the teat skin with >10 6 cfu A. pyogenes led to a low incidence of mastitis even in the absence of cutaneous damage. Repeated applications of lower doses (<10 4 cfu) did not produce infection.

Epidemiology of Oestrus ovis infection of sheep in the highveld of Zimbabwe

During a period of 13 months, 507 heads of sheep, obtained from an abattoir near Harare, were examined for infection with Oestrus ovis larvae. The prevalence of infection varied from 6 to 52%, the highest being in November and the lowest in April. The mean annual larval burden was 1.12. The maximum number of larvae recovered from a single head was 57 in the month of November. Two larval peaks were observed, the first and highest in November and the second in August/September. Some flies are present throughout the year, except in May. There are at least 3 generations of flies per year. The wet summer period from January to May seems to be unfavourable, as very few flies are present. There is no overwintering of first instar larvae in the heads of sheep.

Olfactory sensilla on the antenna and maxillary palp of the sheep head fly, Hydrotaea irritans (Fallen) (Diptera : Muscidae)

Antennae and maxillary palps of both sexes of the Sheep Head fly Hydrotaea irritans (Diptera : Muscidae) were investigated using scanning electron microscopy to describe the types, morphology, and distribution of olfactory sensory structures. Only socketed bristles and microtrichia were found on the scape of the antennae. These structures were also observed on the pedicel together with a group of 7–8 as yet undescribed sensilla, whose function is unknown. Olfactory sensilla were not found on these 2 segments or on the arista. Large numbers of olfactory sensilla and microtrichia were present on the funiculus. The former included sensilla trichodea (thick-walled, multiporous sensilla), sensilla styloconica and 6 types of sensilla basiconica (thin-walled, multiporous sensilla), 4 of which occurred individually and 2 of which were found in groups. An olfactory pit containing groups of thin-walled multiporous sensilla was located on the dorsomedian side of the funiculus. All sensilla basiconica were classified on morphological characteristics. The maxillary palps were covered with microtrichia and socketed bristles, but only 1 type of olfactory sensillum was found. This was a type of sensillum basiconicum that differed from any of those found on the antennae. No differences were found in sensilla diversity and distribution between males and females.

Insect transmission of capripoxvirus

Capripoxvirus was transmitted between sheep using Stomoxys calcitrans as a vector. Attempts to transmit capripoxvirus between sheep and between goats using biting lice (Mallophaga species), sucking lice (Damalinia species), sheep head flies (Hydrotaea irritans) and midges (Culicoides nubeculosus) were unsuccessful, although capripoxvirus was isolated from sheep head flies that had previously fed on infected sheep.

Energy requirements for the penetration of heads of domestic stock and the development of a multiple projectile.

The forces and kinetic energy required to penetrate the isolated heads of calves, adult beef cattle, sheep and red deer with a metal probe the same diameter as the bore of an experimental pistol were determined. Approximately 16 and 127 Joules were required to penetrate the heads of adult sheep and cattle, respectively. Using these data a 10 g projectile, consisting of 49 lead pellets and a lead disc in a polyethylene sleeve, was constructed. This projectile, when fired by a charge sufficient to produce a muzzle velocity of 165 m/second, had sufficient kinetic energy to penetrate the heads and brains of cattle, sheep, horses and deer. The projectile was fired from a new design of humane killer with a spring loaded barrel and fitted with a silencer. After penetration of the frontal bones the projectile fragmented and the kinetic energy of its individual particles were insufficient for them to penetrate the opposite side of the head of any of the animals, including one-week-old calves. Fragmentation also caused more brain damage and inhibition of spinal reflexes than a solid free bullet or captive bolt. It is suggested that the use of such a projectile for the emergency slaughter of animals is less hazardous than a solid free bullet and is easier to use and more effective than either a solid free bullet or captive bolt. The projectile was not suitable for killing adult pigs because of problems associated with the frontal sinus.