Уточнить поиск
Результаты 41-50 из 572
Effects of larkspur (Delphinium barbeyi) on heart rate and electrically evoked electromyographic response of the external anal sphincter in cattle
2009
Green, Benedict T. | Pfister, James A. | Cook, Daniel | Welch, Kevin D. | Stegelmeier, Bryan L. | Lee, Stephen T. | Gardner, Dale R. | Knoppel, Edward L. | Panter, Kip E.
Objective--To determine whether larkspur-derived N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-type alkaloids alter heart rate and electrically evoked electromyographic (eEMG) response of the external anal sphincter (EAS) in cattle and whether these effects can be reversed by acetylcholinesterase inhibitors. Animals--12 beef heifers and 4 cows. Procedures--3 or 4 heifers were used in 1 or 2 of 7 dose-response experiments; heart rate and EAS eEMG response were assessed before and 24 hours after oral treatment with larkspur (doses equivalent to 0.5 to 15 mg of MSAL-type alkaloids/kg). In 3 subsequent experiments, 3 heifers (1 of which was replaced with another heifer in the control experiment) each received 10 mg of MSAL-type alkaloids/kg and were injected IV with physostigmine (0.04 mg/kg), neostigmine (0.04 mg/kg), or saline (0.9% NaCl) solution 24 hours later, prior to assessment. Additionally, EAS eEMG response was measured in 4 cows before and after epidural administration of 2% lidocaine hydrochloride. Results--Larkspur-treated heifers developed dose-related increases in heart rate and decreases in EAS eEMG response. Twenty-four hours after administration of MSAL-type alkaloids, neostigmine decreased heart rate but did not affect eEMG response, whereas physostigmine did not affect heart rate but caused a 2-fold increase in eEMG response. In cows, epidural anesthesia did not alter eEMG response, suggesting that transdermal stimulation of the EAS pudendal innervation did not occur. Conclusions and Clinical Relevance--In cattle, cardiac effects and muscle weakness or loss of EAS eEMG response induced by larkspur-derived MSAL-type alkaloids were reversed by neostigmine or physostigmine, respectively. Treatment with anticholinesterase inhibitors may alter the clinical effects of larkspur poisoning in cattle.
Показать больше [+] Меньше [-]Blood platelet counts, morphology and morphometry in lions, <i>Panthera leo</i>
2009
L. Du Plessis
Due to logistical problems in obtaining sufficient blood samples from apparently healthy animals in the wild in order to establish normal haematological reference values, only limited information regarding the blood platelet count and morphology of free-living lions (Panthera leo) is available. This study provides information on platelet counts and describes their morphology with particular reference to size in two normal, healthy and free-ranging lion populations. Blood samples were collected from a total of 16 lions. Platelet counts, determined manually, ranged between 218 and 358 x 109/ℓ. Light microscopy showed mostly activated platelets of various sizes with prominent granules. At the ultrastructural level the platelets revealed typical mammalian platelet morphology. However, morphometricanalysis revealed a significant difference (P < 0.001) in platelet size between the two groups of animals. Basic haematological information obtained in this study may be helpful in future comparative studies between animals of the same species as well as in other felids.
Показать больше [+] Меньше [-]Assessing the economics of animal trypanosomosis in Africa - history and current perspectives : vector-borne diseases : trypanosomosis
2009
A.P.M. Shaw
Finding appropriate ways of dealing with the problem of tsetse and trypanosomosis will be an important component of efforts to alleviate poverty in Africa. This article reviews the history of economic analyses of the problem, starting with the use of cost to guide choice of technique for tsetse control in the 1950s, followed by work in the 1970s and 1980s linking these to the impact of the disease on livestock productivity, and in the 1990s to its wider impact. In the current situation, with limited resources and a range of techniques for controlling or eliminating tsetse, the cost implications of choosing one technique or another are important and a recent study reviewed these costs. A novel approach to assessing the potential benefits from removing trypanosomosis by creating 'money maps' showed that high losses from animal trypanosomosis currently occur in areas with high cattle population densities on the margins of the tsetse distribution and where animal traction is an important component of farming systems. Given the importance of the decisions to be made in the next decade, when prioritising and choosing techniques for dealing with tsetse and trypanosomosis, more work needs to be done underpinning such mapping exercises and estimating the true cost and likely impact of planned interventions.
Показать больше [+] Меньше [-]Molecular monitoring of African swine fever virus using surveys targeted at adult Ornithodoros ticks : a re-evaluation of Mkuze Game Reserve, South Africa
2009
L.F. Arnot | J.T. du Toit | A.D.S. Bastos
The Mkuze Game Reserve (MGR), in north-eastern KwaZulu-Natal Province, South Africa is an African swine fever virus (ASF) controlled area. In a survey conducted in 1978, ASF prevalence in warthogs and Ornithodoros ticks in MGR was determined to be 2 % and 0.06 %, respectively. These values, acknowledged as being unusually low compared to other East and southern African ASF-positive sylvatic-cycle host populations, have not been assessed since. The availability of a sensitive PCR-based virus detection method, developed specifically for the sylvatic tampan host, prompted a re-evaluation of ASF virus (ASFV) prevalence in MGR ticks. Of the 98 warthog burrows inspected for Ornithodoros presence, 59 (60.2 %) were found to contain tampans and tick sampling was significantly male-biased. Whilst gender sampling-bias is not unusual, the 27 % increase in infestation rate of warthog burrows since the 1978 survey is noteworthy as it anticipates a concomitant increase in ASFV prevalence, particularly in light of the high proportion (75 %) of adult ticks sampled. However, despite DNA integrity being confirmed by internal control amplification of the host 16S gene, PCR screening failed to detect ASFV. These results suggest that ASFV has either disappeared from MGR or if present, is localized, occurring at exceptionally low levels. Further extensive surveys are required to establish the ASFV status of sylvatic hosts in this controlled area.
Показать больше [+] Меньше [-]Detection of testosterone residues in farm fish tissue
2009
H. R. Abdel-Dayem | Hanaa M. Soltan | G. Naser
A total of one hundred samples of marketed fish farm; 25each of tilapia (Oreochromis niloticus), Mugil cephalus, Carp (Silver) and fry; were collected from different localities at Al- Behera and Kafr El-Shakh Provinces. The samples were examined for detection of testosterone hormone by Thin Layer chromatography (TLC) as well as it was quantitatively assayed by Radio-Immuno-Assay (RIA). The obtained result revealed that the testosterone residues were detected in flesh of farm fish of Tilapia (Oreochromis nilotocus) and Carp (Silver), each constituting 24% and 4 %; respectively but it could be failed to detect in each of Mugil cephalus and fry. The hormonal residues of testosterone was ranged from 3.25 to 34.9 ng/g with mean value 4.22±1.1 ng/g in positive samples of Tilapia, while only one sample of Carp showed 22.0 ng/g, Mugil cephalus and Fry showed no detectable level of hormonal residues. The public health significance of detectable levels was discussed as well as the recommendations to avoid health hazards from such fish were mentioned.
Показать больше [+] Меньше [-]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.
Показать больше [+] Меньше [-]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.
Показать больше [+] Меньше [-]In vivo and in vitro study on the effect of Bacillus subtilis and its byproducts on Clostridium perfringens Type A
2009
I. A. Radwan | Eman R. Hassan
The objectives of this study were to screen the possible effects of B. subtilis and its soluble byproducts against C. perfringens, a causative agent of necrotic enteritis (NE) in chickens. The use of B. subtilis strain was found to be inactive in vitro against C. perfringens but its cell filtrate byproducts produced after growth of B. subtilis at 37°C with medium pH adjusted at 5.0, having inhibitory effect in the form of inhibitory zones; measured inhibition of 12 mm. The produced anticlostridial factor was not affected by heat treatment at 70, 100 or 121°C for 15 minutes. The study recorded the responses of broiler chickens to oral administration of C. perfringens and the possible antagonistic effects of B. subtilis and its cell-free filtrate byproducts in vivo. Results revealed that B. subtilis decreased the severity of intestinal necrotic lesions produced after oral inoculation of C. perfringens and the suggested anticlostridial effect was more clear when the cell- free filtrate produced by growing B. subtilis at 37°C with pH 5.0 was added to feed at a dose of 20 ml/kg of ration.
Показать больше [+] Меньше [-]Impact of age at first calving on reproduction, lactation, postpartum disorders and longevity in Holsteins under Egyptian circumstances
2009
M. M. Hussein | A. A. A. El Agawany
A retrospective study including reproductive and productive data of 1587 primiparous Holstein cows covering a period of eight years. The reproductive data ( interval to 1st service, service period, days open, number of inseminations per conception and calving interval ) and the productive data ( total milk yield, average daily milk yield and 305 day milk yield) were studied as a function of age at first calving and postpartum disorders. Furthermore, other data including life span longevity, number of parities, the cumulative productive days and the average calving interval were also studied as a function of age at first calving. Cows were classified according to the age at first calving into young age calvers (< 24 months), mid age calvers (> 24-28 months) and old age calvers (> 28 months). The obtained data were statistically analyzed, tabulated and discussed. The overall mean age at first calving was 26.68 months in Holstein cows under Egyptian circumstances. Most of first calving (90%) were recorded in cows less than 30 month of age. The results indicated that, the young age calvers tend to have prolonged interval to 1st service, days open and calving interval and the reverse was correct in old age calvers. The postpartum disorders had significantly detrimental effects on the reproductive performance among the different age groups. Young age calvers had a higher incidence of postpartum disorders than those of mid - age calvers and much higher than had the old age group. The postpartum disorders were associated with high milk production specially in mid and old age calvers which may indicate the high predisposition of superior producer cows to postpartum disorders. Life span, longevity, number of parities and the cumulative production days were found to be increased as a function of age at first calving. Meanwhile, the average calving interval of the young age calvers was longer than the other two age groups. Finally, it was recommended to avoid insemination of maiden Holstein heifers less than 17 month of age specially those having superior productive traits.
Показать больше [+] Меньше [-]Molasses as a possible cause of an ''endocrine disruptive syndrome'' in calves
2009
M.S. Masgoret | C.J. Botha | J.G. Myburgh | T.W. Naude | L. Prozesky | V. Naidoo | J.H. van Wyk | E.J. Pool | G.E. Swan
During the mid 1990s a potentially serious, chronic syndrome was reported in well-managed beef and dairy herds from unrelated parts of South Africa. Farmers reported that it manifested as various combinations of decreased production, decreased weaning masses, apparent immune breakdown in previously immunocompetent animals, increased reproductive disorders, various mineral imbalances in non-deficient areas and goitre, noticeable as enlarged thyroid glands. The farmers associated this syndrome with certain batches of sugar cane molasses and molasses-based products. The syndrome was reminiscent of an ''endocrine disruptive syndrome''. The objective of this study was to evaluate the suspected endocrine disruptive effect of molasses included in cattle feed. Using existing in vitro assays, four batches of molasses syrup were screened for possible inclusion in a calf feeding trial. Two batches were selected for the trial. Thirty-two, 4- to 6-week-old, weaned Holstein bull calves were included in the single phase, three treatment, parallel design experiment. In two of the groups of calves, two different batches of molasses were included in their rations respectively. The control group was fed a ration to which no molasses was added, but which was balanced for energy and mineral content. The mass gain of the calves was recorded over the 6-month study period. The calves were clinically examined every week and clinical pathology parameters, immune responses and endocrine effects were regularly evaluated. Even though endocrine disrupting effects were detected with the in vitro screening assays, these could not be reproduced in the calves in the experiment. The two batches of molasses utilized in the calf feeding trial did not induce major differences in any of the parameters measured, with the exception of a lower mass gain in one of the molasses-fed groups (Group 1), which tended towards significance. The results of the study indicate that the two batches of molasses had no endocrine disruptive or immunosuppressive effects in calves.
Показать больше [+] Меньше [-]