Уточнить поиск
Результаты 1-10 из 572
More appropriate disease control policies for the developing world Полный текст
2009
Mariner, Jeffrey C.
Investment in disease control should be targeted to critical points that provide the greatest benefit to the livelihoods of livestock-dependent stakeholders. Risk-based targeting should balance the impacts of diseases against the feasibility of their control. This requires sensitive and specific surveillance systems that provide representative overviews of the animal health situation for accurate assessment of disease impact and transmission patterns. Assessment of impact should include household and market effects. The key in surveillance is involving livestock owners using active methods that ensure their disease priorities are addressed. Epidemiological targeting of interventions to critical points in disease transmission cycles should be done to obtain maximal disease reduction. Interventions should be delivered in full partnership with both private and community-based stakeholders to assure high uptake and sustainability. In developing countries, approaches such as participatory disease surveillance and community-based animal health programs have been effective and comply with international animal health standards.
Показать больше [+] Меньше [-]Evaluation of the control of pathogen load by an anti-Salmonella bacterium in a herd of cattle with persistent Salmonella infection Полный текст
2009
Patton, Toni G. | Sharma, Vijay K. | Carlson, Steve A.
To determine whether an anti-Salmonella bacterium is involved in control of pathogen load in persistently infected cattle herds. 24 Holstein calves experimentally infected and 39 Holstein cows naturally infected with Salmonella spp. An Escherichia coli (designated as P8E5) that possessed anti-Salmonella activity was isolated from Salmonella-negative bovine feces obtained from a herd with endemic Salmonella infection. In vitro analysis involved enumerating Salmonella enterica serovar Typhimurium coincubated with E coli P8E5. In vivo analysis involved coadministration of Salmonella spp and E coli P8E5 or an E coli control strain to neonatal Holstein calves. Fecal samples were collected on multiple days after inoculation, and quantitative PCR assay was performed by use of Salmonella-specific primers. E coli P8E5 reduced viability of Salmonella spp in vitro. Shedding of Salmonella organisms was diminished in calves administered E coli P8E5, whereas the control strain of E coli had no effect on shedding of Salmonella organisms. In this study, an E coli strain was identified that possessed bacteriocin-like activity and was able to decrease viability of Salmonella organisms in vitro and in vivo. Therefore, it is possible that this organism could be representative of native microbiota that dampen Salmonella spp in persistently infected cattle herds.
Показать больше [+] Меньше [-]Effects of larkspur (Delphinium barbeyi) on heart rate and electrically evoked electromyographic response of the external anal sphincter in cattle Полный текст
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 [-]Effect of twin vs. single births on gestation length, reproductive performance, dystocia, calf survival rate and culling in Holstein cows Полный текст
2009
A. S. Mostafa
Data of Holstein dairy cows in a private farm (TEC-DAP) in Al-Fayum Governorate comprising 5815 calving events (80 for twins and 5735 for singles) in the period from January 1997 to April 2008 were used to determine if there was any significant difference between twin and single calving cows in gestation length, reproductive performance, incidence of dystocia, perinatal calf survival and mortality rates and culling rate. Cows giving twins had shorter (p < 0.0001) gestation and more (p < 0.005) days to first heat, first service and days open than cows giving singles. Incidence of dystocia was higher in cows with twins (22.5%) than those with singletons (7.22%). Survival rate of singles was 12.9% greater than that of twins at birth, whereas perinatal mortality rate was 16.25 % (9.37% stillborn & 6.88% dead after birth) for twins and 3.33% (2.06% stillborn & 1.27% dead after birth) for singles. Culling rate was greater in cows producing twins (61.53%) than those with singles (30.73%). Twinning in cattle shortens the length of gestation, impairs subsequent reproductive performance by prolonging postpartum breeding intervals, increases the incidence of dystocia and perinatal calf mortality and increases number of cows to be culled during subsequent lactation. Thus, twinning in dairy cattle is undesirable due to its detrimental effect on cow fertility and health and calf survival. However, these adverse effects can be minimized by preparturient diagnosis of twin pregnancy and timely administration of obstetrical assistance which aids in management of dystocia to facilitate delivery of twin calves and to increase their neonatal survival.
Показать больше [+] Меньше [-]Blood platelet counts, morphology and morphometry in lions, <i>Panthera leo</i> Полный текст
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 [-]Seroprevalence of <i>Cryptosporidium parvum</i> infection of dairy cows in three northern provinces of Thailand determined by enzyme-linked immunosorbent assay using recombinant antigen CpP23 Полный текст
2009
T. Inpankaew | S. Jittapalapong | J. Phasuk | N. Pinyopanuwut | W. Chimnoi | C. Kengradomkit | C Sunanta | G Zhang | G.O. Aboge | Y. Nishikawa | I. Igarashi | X. Xuan
Cryptosporidium parvum is the most frequent parasitic agent that causes diarrhoea in AIDS patients in Thailand. Cryptosporidiosis outbreaks in humans may be attributed to contamination of their drinking water from infected dairy pastures. A 23-kDa glycoprotein of C. parvum (CpP23) is a sporozoite surface protein that is geographically conserved among C. parvum isolates. This glycoprotein is a potentially useful candidate antigen for the diagnosis of cryptosporidiosis by enzyme-linked immunosorbent assay. Therefore, we investigated the seroprevalence of C. parvum infection in dairy cows in northern Thailand using an ELISA based on recombinant CpP23 antigen. Sera were randomly collected from 642 dairy cows of 42 small-holder farmers, which had the top three highest number of the dairy cows' population in Northern Thailand, that included Chiang Mai, Chiang Rai and Lumpang provinces. The overall seroprevalence of the infection was 4.4 %, and the seropositive rates for the three provinces were 3.3 % in Chiang Mai, 5.1 % in Chiang Rai and 3 % in Lumpang. These results suggest that cattle could play a role in zoonotic cryptosporidiosis in Thailand.
Показать больше [+] Меньше [-]Veterinary education in Africa : current and future perspectives : animal health management in the 21st century Полный текст
2009
G.E. Swan | N.P.J. Kriek
Veterinary education commenced in South Africa in 1920 at the Onderstepoort Veterinary Institute in South Africa in association with the Transvaal University College, now the University of Pretoria. Sir Arnold Theiler, Director of Veterinary Research and Education, was the first Dean. Today there are 46 veterinary training institutions in Africa of which 21 are in sub-Saharan Africa.Veterinary services are indispensable to the sustained health and wellbeing of animals and humans, and agricultural economies of countries worldwide. Veterinary education, postgraduate training, and research, and adequate numbers of veterinarians, are essential to satisfy the millennium development goals, the objectives of NEPAD and the African Union, and the agreements regulating international trade.
Показать больше [+] Меньше [-]Morphology of the tongue of the emu (<i>Dromaius novaehollandiae</i>). I. Gross anatomical features and topography Полный текст
2009
M.R. Crole | J.T. Soley
Despite numerous papers addressing the topic, the gross morphology of the ratite tongue and more specifically that of the emu, has been superficially or poorly described. This paper presents the first definitive macroscopic description of the emu tongue and reviews, consolidates and compares the scattered information on the gross morphology of the ratite tongue available in the literature. Twenty-three heads obtained from birds at slaughter were used for this study. Specimens were fixed in 10 % neutral buffered formalin, rinsed and the gross anatomy described. The emu tongue is divided into a body and a root. The body is triangular, dorsoventrally flattened, pigmented and displays caudally directed lingual papillae on both the lateral and caudal margins. The root, a more conspicuous structure in comparison to other ratites, is triangular, with a raised bulbous component folding over the rostral part of the laryngeal fissure. Following the general trend in ratites, the emu tongue is greatly reduced in comparison to the bill length and is specifically adapted for swallowing during the cranioinertial method of feeding employed by palaeognaths. This study revealed that it is not only the shape of the tongue that differs between ratites, as previously reported, but also its colour, appearance of its margins and root, and its length in comparison to the bill, and the shape of the paraglossum.
Показать больше [+] Меньше [-]Ticks collected from birds in the northern provinces of South Africa, 2004-2006 Полный текст
2009
G. Hasle | I.G. Horak | G. Grieve | H.P. Leinaas | F. Clarke
Approximately 3 000 birds, mainly passerines, caught in mist nets in the northern provinces of South Africa, were examined for ticks. A total of 178 ticks, belonging to 14 species, were recovered from 83 birds of 43 different species. Hyalomma rufipes was the most numerous tick, with 26 larvae and 109 nymphs collected, followed by Amblyomma marmoreum, with 13 larvae and two nymphs. Despite the study being conducted within the distribution range of Amblyomma hebraeum, it was not seen on any passerines, whereas three larger species were infested. The potential for small birds to spread ticks with their associated tick-borne pathogens is discussed.
Показать больше [+] Меньше [-]Poisonous plants : historical overview : Onderstepoort and veterinary research in Africa Полный текст
2009
T.S. Kellerman
South Africa is blessed with one of the richest floras in the world, which - not surprisingly - includes many poisonous plants. Theiler in the founding years believed that plants could be involved in the aetiologies of many of the then unexplained conditions of stock, such as gousiekte and geeldikkop. His subsequent investigations of plant poisonings largely laid the foundation for the future Sections of Toxicology at the Institute and the Faculty of Veterinary Science (UP). The history of research into plant poisonings over the last 100 years is briefly outlined. Some examples of sustained research on important plant poisonings, such as cardiac glycoside poisoning and gousiekte, are given to illustrate our approach to the subject and the progress that has been made. The collation and transfer of information and the impact of plant poisonings on the livestock industry is discussed and possible avenues of future research are investigated.
Показать больше [+] Меньше [-]