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Theiler and the 'Spirit of Onderstepoort' Introductory keynote address : historical overview : Onderstepoort and veterinary research in Africa
2009
R.D. Bigalke
Although Theiler became internationally known for his pioneering veterinary research a distant century ago, there are probably few veterinary researchers today who have not heard of him. Onderstepoort, the research institute he created, is equally well, if not even better, known. Moreover, the name Onderstepoort is not only associated with his institute but also with the only South African faculty of veterinary science, another Theiler 'baby'. The purpose of this presentation is to determine why this was so, and to what extent the fame was justified. Was it due to the 'Spirit of Onderstepoort' sometimes referred to by Theiler in the early as well as later stages of his career, or was there perhaps more to it, and what was Theiler's share in the development of that spirit, that fame
اظهر المزيد [+] اقل [-]Supplementation of antioxidants for in Vitro embryo production of buffaloes
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 [-]Livestock policy and trade issues in SADC : policy and trade issues
2009
B. Hulman
As from 2001, the Southern African Development Community (SADC) has embarked on a course to deepen regional integration through restructuring. Under the new structure SADC has centralised the coordination of its activities to the Secretariat in Gaborone. The former Sector Coordinating Units have been merged into four directorates, one of which is the Food, Agriculture and Natural Resources (FANR) Directorate, which comprises, amongst others, the Livestock Development Unit (LDU).
اظهر المزيد [+] اقل [-]Field study on control of chronic respiratory disease in vertically infected broiler chicks
2009
M. M. Amer | K. M. El-Bayomi | Zenab, M. S. Gera | A. E. A. Hanafei
Our field studies had been carried out after in vitro antibiogram of E. coli to compare the effect of pulmotil (macroloide), enerofloxacin (fluoroquinolones) and doxycycline (tetracycline) in controlling mycoplasma and E. coli as a cause of CRD in broilers. The drugs were used in single or in combination. Two doses at the 3rd and 23rd day of age on performance of commercial broiler Ross derived from mycoplasma SPA-test positive breeders and E. coli positive isolation at the 1st day of age. The prevalence of marked air sac gross lesions in non treated control group indicated the development of CRD and severity of lesions increased with age. The used drugs played a role in controlling infection as treated groups showed milder lesions while more sever lesions were in doxycycline treated group. Protection against mortality was less in the treated pins than untreated ones. Cumulative culls % was low (1.1) in pen treated with enrofloxacin, (1.5) in pulmotil + enrofloxacin, (1.6) in doxycycline, and (1.7) in pulmotil + enrofloxacin; while pulmotil and control were the same (2.2%). Losses expressed as total mortality and culls % were the lowest in pulmotil + enrofloxacin and enrofloxacin (3.2 and 3.6), other treated pins showed the same values (4.2), while the highest was in non treated ones (5.8%). Average Body wt. in pulmotil + enrofloxacin, pulmotil, and enrofloxacin treated pens were higher (1934, 1924 and 1819 gm) than doxycycline (1802 gm), Pulmotil + Doxycycline (1705 gm) and non treated control (1708 gm). CFCR in pulmotil or enrofloxacin and in combination medicated pens were higher than other treatments and non medicated pen. Average day/ week/ gain in control non treated was equal to that of pulmotil or enrofloxacin (65g), slight lower value was in their combination (63g) followed by 58 g in doxycycline. The lowest ADG /w/g value was in pulmotil + doxycycline (52 g). Calculated EEF of treated and non medicated pens were higher than > 280. The medicated pens with either pulmotil or/ enrofloxacin and there compilation were superior (333, 313 and 330; respectively) and close to the farm stander (346). This study pointed out that E. coli, and Mycoplasma with life ND vaccine reduced broiler performance and the used drugs were of values in control such infections. The in vitro antibiotics sensitivity testing of E. coli is important to obtain good results and drug combinations must be carefully performed.
اظهر المزيد [+] اقل [-]Studies on the cumulative effect of sodium thiomersal on broilers vaccinated with inactivated poultry vaccines
2009
Zeinab M. Sror | Anhar Abd El-Moety | Hanan, M. Ibrahim | M. L. Sayed, A. R. Mahmoud | A. R. Mahmoud | S. M. Shafei | M. H. Khodeir
Merthiolate (Thiomersal) is known to be used as antimicrobial agent in inactivated vaccines without affecting vaccine potency. The present work investigated the effect of thiomersal contents in ND, AI and IBD inactivated vaccines on liver and kidney functions of vaccinated birds. The histopathological effect and the withdrawal time of such mercurial product from vaccinated chicken muscles were also investigated. Results revealed that residual thiomersal contents in ND, AI and IBD were 0.03; 0.02 and 0.03mg/ml respectively. Liver and kidney function parameters showed significant increases in serum activities of alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST) up to the 4th week post vaccination. Serum urea was significantly decreased on the 3rd week in vaccinated birds compared to control ones. Significant increase in serum creatinine in vaccinated chickens was recorded on the 5th week post vaccination. Liver and kidney functions’ parameters remain high allover the experimental period (8 weeks). The histopathological examination of liver specimens revealed degeneration of hepatic cells and congestion of the central vein with inflammatory cell infiltration and congestion of blood vessels as well as coagulative necrosis. The spleen of vaccinated chickens showed depletion of lymphocytes while lungs showed thickening of the alveolar. Mercury contents in muscle were 0.72, 0.52; 0.046 and 0.00 mg/kg on the 1st, 2nd, 3rd and 4th week post last vaccination that considered safe to the consumer. It is recommended that vaccinated poultry with inactivated vaccines containing thiomersal should not be slaughtered before at least 4 weeks and it is preferable to use combined inactivated vaccines to reduce the thiomersal contents as possible.
اظهر المزيد [+] اقل [-]Twinning in dairy cattle and its effect on milk yield, lactation length, dry period length and calf performance
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 [-]A study on the biological and immunological characteristics of Listonella anguillarum and Vibrio vulnificus extracellular products
2009
F.R. El-Seedy | W.H. Hassan | Hala A. El-Newery | Mona, M. Husien
Two fish pathogens, namely Listonella anguillarum (Vibrio anguillarum) and Vibrio vulnificus, which were beta-haemolytic, hemagglutinating with 1% D-mannose and hydroxamate siderophore producer were used in this study. The extracellular products (ECPs) of both species were of high enzymatic and haemolytic activities. SDS-PAGE analysis of ECPs of L. anguillarumand V. vulnificus revealed 4 band (20.7 to 47.5kDa) and 2 bands (30.1 to 46kDa) respectively. The cumulative mortalities in O. niloticus produced by crude ECPs of L. anguillarum (0.2ml/fish; 2.4mg protein /ml) and V. vulnificus (0.2ml/fish; 1.6mg protein /ml) were 90% and 80%. Heat treatment of ECPs of L. anguillarum and V. vulnificus at 56°C for 30 min reduced the mortalities to 30% and 20%, respectively. LD50 values in O. niloticus using crude and heat treated ECPs of L. anguillarum were 1.7 and 3.9 ^g protein/g fish; while those of V. vulnificus were 1.34 and 2.8 ^g protein /g fish, respectively. Injection of levamisole at a dose of 5mg/Kg fish, concurrently with ECPs of L. anguillarum and V. vulnificus resulted in subsidence of the mortality percentages from 90 to 40 and from 80 to 30, respectively. Ten laying hens were immunized with ECPs of L. anguillarum for preparation of specific egg immunoglobulins. The total protein content of IgY preparations collected from eggs of hens immunized with ECPs of L. anguillarum reached its peak 2 weeks post 3rd booster dose (3.820 ± 0.0700 g/dl). The molecular weight of separated protein bands of IgY preparations ranged from 183-191kDa. Fish injected (I/P) with specific anti ECPs IgY of L. anguillarum (4 mg/ fish) followed by I/P injection of ECPs of L. anguillarum (0.2 ml/fish; 2.4 mg protein /ml) showed a 10% mortality rate, while those challenged after receiving specific anti ECPs (100 mg/ kg B.W. orally) showed no mortalities.
اظهر المزيد [+] اقل [-]A century of tick taxonomy in South Africa : tick-borne diseases
2009
I.G. Horak
Eighty ixodid tick species, 25 argasid tick species and Nuttalliella namaqua occur in South Africa. Twenty-one of the 80 ixodid species and two of the argasid species occur only in this country, while N. namaqua is present only in South Africa and Namibia. Forty-six of the 80 ixodid species and 16 of the 25 argasid species as well as N. namaqua have been described as new species since 1908. People working in South Africa have written or contributed to the descriptions of 24 of these 63 new species, while foreign researchers have described the remainder. New species indigenous to South Africa are still being discovered, while the names of some species, well known because of their veterinary importance, have been altered.
اظهر المزيد [+] اقل [-]The effects of low levels of dietary trace minerals on the plasma levels, faecal excretion health and performance of pigs in a hot African climate
2009
M.H. Boma | G. Bilkei
The present study was performed in order to evaluate the effects of lower than usual industry levels of dietary trace minerals on plasma levels, faecal excretion, performance, mortality and morbidity in growing-finishing pigs in a hot African climate. Group 1 (n =100 pigs) received a diet with common industry levels of trace minerals. Group 2 (n =100 pigs) received reduced dietary trace mineral levels but were fed the same basic diet as Group 1. Mortality, morbidity, pig performance and carcass measurements were evaluated. Two pigs in Group 1 and three pigs in Group 2 died. Thirteen pigs in Group 1 and 27 pigs in Group 2 were medically treated (P < 0.05). Carcass masses, back fat depth, loin depth, and lean percent were not significantly different between the groups. However, the carcasses when evaluated revealed a non-significant higher back fat thickness, lower loin eye area and percentage of fat free lean in barrows compared to gilts within each group. Despite lower initial masses, pigs fed diets containing industry levels of trace minerals were heavier (P < 0.05) and had a higher (P < 0.05) than average daily gains compared to those that received a diet containing lower levels of trace minerals. Faecal zinc excretion was significantly lower (P < 0.05) in pigs fed with lower dietary zinc levels. Copper, manganese and iron excretion were not affected (P > 0.05) by the dietary levels of these trace minerals. Plasma trace mineral concentrations were not affected by the dietary treatment.
اظهر المزيد [+] اقل [-]Some pharmacodynamic interactions between salinomycin and vitamin E or selenium in chickens
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.
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