خيارات البحث
النتائج 101 - 110 من 616
Proceedings: Onderstepoort Centenary Pan-African Veterinary Conference : foreword النص الكامل
2009
Editorial Office
In 1908 a Pan-African Veterinary Conference formed part of the inauguration ceremony of the Onderstepoort Veterinary Laboratory. Attended by 18 delegates from 12 countries in southern Africa, including the four colonies and three protectorates forming British South Africa, Rhodesia, German South West Africa, Portuguese East Africa, Madagascar and the Belgian Congo, discussions focussed on the animal diseases of the region with the emphasis on trypanosomosis (nagana) and East Coast fever. The successful meeting was followed by a series of similar conferences held in different African countries during the first half of the 20th Century.
اظهر المزيد [+] اقل [-]Pharmacokinetic profile and some pharmacodynamic aspects of cefquinome in chickens النص الكامل
2009
A. A. M. El-Gendy | M. A. Tohamy | Abeer M. Radi
The pharmacokinetic profile and some pharmacodynamic aspects of cefquinome were studied after intramuscular (IM) and subcutaneous (SC) administration of a single dose of 2 mg kg-1 b.wt. in chickens. Tissue distribution and residues of cefquinome after repeated IM injection for 5 consecutive days were also estimated. Cefquinome was rapidly absorbed after IM and SC injection as indicated by short half-lives of absorption (t0.s(ab)) of 0.170 and 0.262 h., respectively, while the elimination half-lives (t05(el)) were 3.428 and 25.023 h., respectively. Repeated IM doses of cefquinome (2 mg kg-1 b.wt., once daily) for 5 consecutive days caused no change in serum enzyme activities of ALT and AST, but induced significant increase in serum uric acid concentration after 72 to 120 hours of administration. The withdrawal time of cefquinome from tissue of chickens is 5 days following the last dose. Cefquinome has a wide spectrum of activity against Esherchia coli, Proteus mirabilis and Pseudomonas aeroginosa.
اظهر المزيد [+] اقل [-]Twinning in dairy cattle and its effect on milk yield, lactation length, dry period length and calf performance النص الكامل
2009
A. S. Mostafa
The twinning rate in a herd of Holstein dairy cattle and its effect on lactation and calf performance was investigated by using records of 5815 calving events. Data from twin calving Holstein cows in (TEC-DAP) farm in Al-Fayum Governorate between January 1997 and April 2008 were compared to those giving singles to study the differences in subsequent milk yield, previous and subsequent lactation and dry period length, as well as calf performance. The obtained average twinning rate was 1.4% during the period of the study. Cows giving twins had a significantly (p<0.01) lower daily, peak and 305-d milk yields than those with singles. There was no significant difference (p>0.05) in previous and subsequent lactation and dry period length between cows calving twins or singles. Calves born as twins were significantly (p<0.005) lighter at birth and weaning time than single calves, whereas total birth weight and total weaning weight were significantly (p<0.005) increased for twins than singles. Daily body weight gain from birth to weaning was significantly lower (p<0.005) for twin than single calves. Twinning in dairy cattle has a negative depressive effect on subsequent milk yield. Calf weight produced at weaning per cow calving can be increased in cows producing twins relative to cows producing singles. Alleviation of twinning constraints including dystocia, reduced calf survival and low reproductive performance requires improved management practices and early diagnosis of cows gestating twins in order to provide higher nutritive requirements in the last trimester of gestation and proper timing of drying off, and for higher assistance requirements at parturition. Thus, due to the increased disadvantages which did not offset the additional returns earned by calves, twinning in dairy cattle via selection or artificial induction appears not to be desirable.
اظهر المزيد [+] اقل [-]Persistence mechanisms in tick-borne diseases : tick-borne diseases النص الكامل
2009
A.F. Barbet
The use of new, highly sensitive diagnostic methods has revealed persistent infections to be a common feature of different tick-borne diseases, such as babesiosis, anaplasmosis and heartwater. Antigenic variation can contribute to disease persistence through the continual elaboration of new surface structures, and we know in several instances how this is achieved. Known or suspected mechanisms of persistence in babesial parasites include cytoadhesion and rapid variation of the adhesive ligand in Babesia bovis and genetic diversity in several merozoite stage proteins of different Babesia spp. In Anaplasma, extensive variation in the pfam01617 gene family accompanies cycling of organism levels in chronic infection. One result from the pioneering research at Onderstepoort is the definition of a related polymorphic gene family that is likely involved in immunity against heartwater disease. We are beginning to understand the sizes of the antigenic repertoires and full definition is close, with the possibility of applying simultaneous high-throughput sequencing to the order of 1 000 small genomes. We also, for the first time, can consider modifying these genomes and looking at effects on persistence and virulence. However, important biological questions remain unanswered; for example, why we are seeing a new emerging Anaplasma infection of humans and is infection of endothelial cells by Anaplasma significant to persistence in vivo.
اظهر المزيد [+] اقل [-]A brief history of botulism in South Africa : historical overview : Onderstepoort and veterinary research in Africa النص الكامل
2009
C.M. Cameron
When looking back into the history of botulism and contemplating the final understanding of the syndrome and the ultimate solutions, there are four facets that stand out clearly. The first is that much of the solution was guided by astute observations, curious travellers, committed veterinarians and particularly farmers themselves who were able to relate the occurrence of the condition to climatic and grazing conditions. Secondly, there was the identification of the osteophagia and pica syndrome which led to the feeding of bone-meal as a successful mitigating measure as well as the establishment that botulism was not due to a plant poisoning. Thirdly, the solution of the problem depended on the integration of experience and knowledge from diverse disciplines such as soil science, animal behaviour and husbandry, nutrition, botany and ultimately advanced bacteriology and the science of immunology. Finally it required the technical advancement to produce toxoids in large quantities and formulate effective aluminium hydroxide precipitated and oil emulsion vaccines.
اظهر المزيد [+] اقل [-]Some anatomical studies on the arterial supply and venous drainage of the tail of the buffalo "Bos Bubalis L." النص الكامل
2009
M. R. A. Gad | Z. A. Adam | M. G. Tawfiek
Twenty tails of buffaloes were used in this study from apparently healthy adult animals. They are dissected to reveal their arteries and veins. Fourteen photographs illustrated the results in the study. The study revealed that the arterial supply of the tail comes from the median caudal, superficial caudal, deep caudal, dorsolateral caudal arteries and the tail is drained by five caudal veins; median caudal, two ventrolateral caudal and two lateral caudal veins.
اظهر المزيد [+] اقل [-]Studies on Edwardsiella tarda infection in catfish and Tilapia nilotica النص الكامل
2009
Heidy Abo El-Yazeed | Mai D. Ibrahem
Edwardsiella tarda was recovered from cultured freshwater catfish (Claries gariepinus) with a prevalence rate of 0.42% in summer season. Experimental infectivity studies of E. tarda in Catfish and Tilapia nilotica were done using the intraperitoneal (I/P) and intramuscular (I/M) routes. Experimentally infected Catfish with a dose of 0.3 ml from E. tarda bacterial suspension of 108 CFU/ml manifested pathognomonic clinical signs and postmortem lesions than the experimentally infected Tilapia nilotica. Application of PCR technique for rapid detection of E. tarda infection in the experimentally infected fishes gave positive reaction in 4th day post infection in catfish and the 7th day post infection in Tilapia nilotica.
اظهر المزيد [+] اقل [-]Supplementation of antioxidants for in Vitro embryo production of buffaloes النص الكامل
2009
S. S. Ibrahim | A. Aboul-Ela | E.A. Mabrouk | K.M. Ali | A. A. Ahmed
Biological hazards associated with oxidative stress resulted in defective in vitro embryo production “IVEP”. Reactive oxygen species “ROS” may originate from embryo metabolism and/or embryo surroundings. In an attempt to overcome such challenge, the present study correlates between the influence of 3 antioxidants and buffalo oocyte development up to morula and blastocyst stages. It was found that taurine addition (either alone or concomitant with ascorbic acid “AA” or mannitol) to media during in vitro maturation “IVM” has the potency to enhance IVEP in buffaloes. On the other side, AA and mannitol either alone or in combination are invalid to improve developmental rate of mature buffalo oocytes to reach morula and blastocyst stages. In a second experiment, the best treatment (taurine and AA) was added to both in vitro fertilization “IVF” and culture “IVC” media. This treatment resulted in significant elevation of the cleavage rate and morula development without influencing blastocyst rate as compared with their corresponding values following the addition to IVM medium alone. Thus, it could be concluded that addition of taurine with AA into both IVM and IVF media enhances maturation of buffalo oocytes and activates the cells to undergo cleavage and morula development.
اظهر المزيد [+] اقل [-]Comparison between urethrostomy and penile resection for treatment of congenital penile urethral dilatation in calves النص الكامل
2009
A. M. Sedeek | H. A. Bakr
A clinical study was conducted under field condition during the period from January 2005 to December 2008 in Beni-Suef province on a total number of 15 calves suffered from congenital penile urethral dilatation at the perineal region. The affection was diagnosed and treated surgically under field condition and treatment included perineal urethrostomy (8 calves) and partial resection of penis including the dilated urethra (7 calves). Results revealed that duration of surgery for urethrostomy was shorter (mean 36.25 minutes) than penile resection (mean 85.71 minutes), bleeding was so extensive in penile resection group than urethrostomy one and cost of surgery was lower for urethrostomy than penile resection but aftercare cost was twice that of penile resection. Complications were higher in urethrostomy group, recovery period was nearly the same in both groups (14.37 and 14.28 days), mean body gain was higher in penile resection group (82 kg) than urethrostomy group (77.14 kg), and both groups considered of low quality animals at market as a result of loss of breeding capability and presence of urine scald. It could be concluded that both techniques are satisfactory but partial penile resection including the dilated urethra is superior to urethrostomy despite the higher cost and invasive surgical procedure.
اظهر المزيد [+] اقل [-]Some pharmacodynamic interactions between salinomycin and vitamin E or selenium in chickens النص الكامل
2009
S.E. El-Sadek | M. A. Tohamy | Abeer A. El-Badry | Noha A. M. Fouad | A. A. M. El-Gendy
The present study was conducted to determine the effect of salinomycin at a concentration 60 and 120 ppm alone and with vitamin E or selenium on haematological and biochemical parameters and histopathological changes of the treated chicken. Salinomycin (120 ppm) induced decrease in body weight, feed consumption and feed conversion efficiency. In addition, when salinomycin (120 ppm) given with vitamin E, the body performance improved significantly, but when sodium selenite used, body performance significantly decreased. Salinomycin at concentration 120 ppm induced decrease in blood parameters (RBCs count, TLC count, Hb content and PCV %). Concurrent use of vitamin E with salinomycin leads to improvement of these parameters. Salinomycin at 120 ppm induced significant increase in enzymes activities (ALT and AST). The uses of vitamin E with slinomycin (120 ppm) caused significant decrease in these activities. In contrast to selenium, which reduce the activity of AST enzyme only. Salinomycin at 120 ppm decreased the total protein concentration and increased the level of creatinine and uric acid. Concurrent administrations of vitamin E or selenium with salinomycin have no effect on these parameters. At 120 ppm salinomycin, selenium increased the creatinine concentration in blood serum. The drug at 60 or 120 ppm induced various pathological changes in certain tissues (liver, heart, kidney and skeletal muscle) ranged from degeneration to necrosis of these tissues. Concurrent administration of salinomycin with vitamin E or selenium revealed that vitamin E decreased the pathological changes of studied tissues.
اظهر المزيد [+] اقل [-]