خيارات البحث
النتائج 91 - 100 من 445
Sample collection factors affect the sensitivity of the diagnostic test for Tritrichomonas foetus in bulls النص الكامل
2003
Parker, Sarah | Campbell, John | Ribble, Carl | Gajadhar, Alvin
The current diagnostic test for Tritrichomonas foetus involves the culture of collected preputial or vaginal samples. In an earlier study, which evaluated sampling tools for use with bulls, it was observed that the sensitivity of the diagnostic test was higher for 2nd samples collected from the right side of the prepuce than it was for samples collected 1st from the left side. The study described in this paper was conducted to evaluate which of these factors was responsible for the effect on diagnostic sensitivity. Twenty-nine bulls infected with T. foetus were repeatedly sampled in a 2-factor cross-over design. Samples taken from the right side of the prepuce were 4 times as likely to be positive as samples taken from the left side (P = 0.03). Other factors did not have a significant effect on the outcome of the diagnostic test. Unexpected factors may affect the sensitivity of the diagnostic test for T. foetus.
اظهر المزيد [+] اقل [-]Results of epidemic simulation modeling to evaluate strategies to control an outbreak of foot-and-mouth disease النص الكامل
2003
Bates, Thomas W. | Thurmond, Mark C. | Carpenter, Tim E.
Objective-To assess estimated effectiveness of control and eradication procedures for foot-andmouth disease (FMD) in a region of California. Sample Population-2,238 herds and 5 sale yards in Fresno, Kings, and Tulare counties of California. Procedure-A spatial stochastic model was used to simulate hypothetical epidemics of FMD for specified control scenarios that included a baseline eradication strategy mandated by USDA and supplemental control strategies of slaughter or vaccination of all animals within a specified distance of infected herds, slaughter of only high-risk animals identified by use of a model simulation, and expansion of infected and surveillance zones. Results-Median number of herds affected varied from 1 to 385 (17% of all herds), depending on type of index herd and delay in diagnosis of FMD. Percentage of herds infected decreased from that of the baseline eradication strategy by expanding the designated infected area from 10 to 20 km (48%), vaccinating within a 50-km radius of an infected herd (41%), slaughtering the 10 highest-risk herds for each infected herd (39%), and slaughtering all animals within 5 km of an infected herd (24%). Conclusions and Clinical Relevance-Results for the model provided a means of assessing the relative merits of potential strategies for control and eradication of FMD should it enter the US livestock population. For the study region, preemptive slaughter of highest-risk herds and vaccination of all animals within a specified distance of an infected herd consistently decreased size and duration of an epidemic, compared with the baseline eradication strategy.
اظهر المزيد [+] اقل [-]Effects of diet formulations containing proteins from different sources on intestinal colonization by Campylobacter jejuni in broiler chickens النص الكامل
2003
Udayamputhoor, Roy S. | Hariharan, Harry | Van Lunen, Ted A. | Lewis, P Jeffrey | Heaney, S. (Susan) | Price, Lawrence | Woodward, David
The objective of this study was to compare the effects of 3 diet formulations containing different protein sources (animal, plant, and a combination of animal and plant) on the colonization of Campylobacter jejuni in the gastrointestinal tract of broiler chickens. A freshly isolated strain of C. jejuni (biotype IV, serotype HS O:21, O:29, HL untypable) from a broiler chicken was used to infect 3-day-old chicks that had been free of C. jejuni; 0.5 mL of an inoculum containing 108 colony-forming units was administered orally. Shedding of the organism was studied, and C. jejuni in the ceca, jejuni, and crop were enumerated by quantitative culture. The isolates recovered from the birds during the study period of 35 d were characterized and confirmed as C. jejuni by the use of standard methods and underwent biotyping, serotyping, antimicrobial susceptibility testing by disk diffusion and the E-test, and flagellin gene typing. A cyclical pattern of shedding of C. jejuni was observed in all the birds. Colonization was highest in the ceca. The ceca of birds receiving plant-protein-based feed had significantly less colonization then the ceca of birds receiving the other types of feed, whereas the differences in colonization of the jejuni and crops were not significant. Characterization by biotyping, serotyping, and flagellin gene typing showed that 95% of the recovered isolates were identical to the strain used for infecting the chicks. However, with the Lior-HL typing scheme, 74% of the recovered isolates were HL untypable. Antimicrobial resistance testing did not reveal significant differences between the infecting strain and the recovered isolates among the different feed groups.
اظهر المزيد [+] اقل [-]Verification by polymerase chain reaction of vertical transmission of Theileria sergenti in cows النص الكامل
2003
Baek, Byeong K. | Soo, Kim B. | Kim, Jin H. | Hur, Jin | Lee, Bou O. | Jung, J.M. | Onuma, Misao | Oluoch, Anthony O. | Kim, Chʻang-hyŏn | Kakoma, Ibulaimu
To evaluate the transplacental transfer of Theileria sergenti infection in cattle, we used DNA probes to detect T. sergenti in 6 pregnant cows and their calves. All the animals were monitored by parasitologic, serologic, and polymerase chain reaction (PCR) assays for a predicted 875-base-pair (bp) DNA product and a 684-bp amplicon detected by nested PCR in the blood and spleens of aborted fetuses. An open reading frame (ORF) starting at nucleotide 170 and terminating at position 1021 was shown to code for a polypeptide of 283 amino acid residues. All 6 dams and 5 calves were positive for T. sergenti in all tests. One calf was positive only with nested PCR. We conclude that transplacental transmission of T. sergenti is a significant problem. The relevance of the data in the programmed introduction of new (especially pregnant) animals into established clean herds needs serious consideration with regard to control of theileriosis and other tickborne diseases.
اظهر المزيد [+] اقل [-]Brucella abortus infection in indigenous Korean dogs النص الكامل
2003
Baek, B.K. | Lim, C.W. | Rahman, M.S. | Kim, C-Hyun | Oluoch, A. | Kakoma, I.
Three dogs reared on a dairy farm with a high incidence for Brucella abortus were serologically positive for B. abortus and no other Brucella spp. The identity of the organism was confirmed to be B. abortus by AMOS (abortus melitensis ovis suis)-polymerase chain reaction with specific primers for B. canis. One hundred percent homology of the canine isolate and the bovine pathogen isolated from the farm was demonstrated. The only possible source of infection was infected cattle on the same farm. It is suggested that dogs be routinely included in brucellosis surveillance and eradication programs.
اظهر المزيد [+] اقل [-]Antagonism of adenosine receptors by caffeine and caffeine metabolites in equine forebrain tissues النص الكامل
2003
Zhou, Jizhong | Vickroy, Thomas W.
Objective-To determine the presence of adenosine receptor subtypes A1 and A2a in equine forebrain tissues and to characterize the interactions of caffeine and its metabolites with adenosine receptors in the CNS of horses. Sample Population-Brain tissue specimens obtained during necropsy from 5 adult male research Procedures-Membrane-enriched homogenates from cerebral cortex and striatum were evaluated by radioligand binding assays with the A1-selective ligand [3H]DPCPX and the A2a-selective ligand [3H]ZM241385. Functional responses to adenosine receptor agonists and antagonists were determined by a nucleotide exchange assay using [35S]-guanosine 5'-(γ-thio) triphosphate [35S]GTPγS). Results-Saturable high affinity [3H]DPCPX binding (A1) sites were detected in cerebral cortex and striatum, whereas high-affinity [3H]ZM241385 binding (A2a) sites were detected only in striatum. Caffeine and related methylxanthines had similar binding affinities at A1 and A2a sites with rank orders of drug binding affinities (theophylline > paraxanthine ≥ caffeine >> theobromine) similar to other species. [35S]GTPγS exchange revealed that caffeine and its metabolites act as pure adenosine receptor antagonists at concentrations that correspond to A1 and A2a receptor binding affinities. Conclusions and Clinical Relevance-Results of our study affirm the presence of guanine nucleotide binding protein linked adenosine receptors (ie, high-affinity A1 and A2a adenosine receptors) in equine forebrain tissues and reveal the antagonistic actions by caffeine and several biologically active caffeine metabolites. Antagonism of adenosine actions in the equine CNS by these stimulants may be responsible for some central actions of methylxanthine drugs, including motor stimulation and enhanced racing performance.
اظهر المزيد [+] اقل [-]Interactions of morphine and isoflurane in horses النص الكامل
2003
Steffey, Eugene P. | Eisele, John H. | Baggot, Desmond
Objective-To quantitate dose- and time-related magnitudes of interactive effects of morphine (MOR) and isoflurane (ISO) in horses and to characterize pharmacokinetics of MOR in plasma and the ventilatory response to MOR during administration of ISO. Animals-6 adult horses. Procedure-Horses were anesthetized 3 times to determine the minimum alveolar concentration (MAC) of ISO in O2 and then to characterize the change in anesthetic requirement as defined by the alteration in ISO MAC following IV administration of saline (0.9% NaCl) solution and 2 doses of MOR (low dose, 0.25 mg/kg; high dose, 2.0 mg/kg). Arterial blood samples were obtained before and after MOR and analyzed. Results-Mean +/- SD baseline ISO MAC was 1.43 +/- 0.06%. The ISO MAC did not change with time after administration of saline solution. Effects of MOR on ISO MAC varied. Maximal change in MAC ranged from –20.2 to +28.3% and -18.9 to +56.2% after low and high doses of MOR, respectively. Typical half-life of MOR in plasma was 40 to 60 minutes and related to dose. Mean PaCO2 increased from 70 mm Hg before MOR to 88 to 102 mm Hg for 30 to 240 minutes after the high dose of MOR. Recovery from anesthesia after administration of the high dose of MOR was considered undesirable and dangerous. Conclusions and Clinical Relevance-Our results do not support routine clinical use of MOR administered IV at dosages of 0.25 or 2.0 mg/kg as an adjuvant to anesthesia in horses administered ISO.
اظهر المزيد [+] اقل [-]Proportion of edible and non edible body parts in different strains of laying chickens
2003
Bhatti, B.M. | Anjum, A.R. | Bhatti, S.U. (Poultry Research Inst., Rawalpindi (Pakistan))
This study was conducted to ascertain anatomical variation in different body parts of Desi, Fayoumi, Cross (Rhode Island Red x Fayoumi) and Nick Chick laying hens. A total 16 laying hens of average body weight were selected using random numbers out of 2600 laying hens, slaughtered and eviscerated. It was observed that proportion of neck, ribs, breast, back, wings, thigh and legs out of aggregate weight was highest (51.74 plus minus 2.85) in Fayoumi hens. The proportion of liver, gizzard, heart and spleen combined weight was highest (6.05 plus minus 1.81) in desi hens. The proportion of non edible offals including trachea, lungs, kidneys, blood, feathers, head, crop, proventriculus, intestines, shanks, gizzard waste, skin, tail, testes, ova, oviduct and fat was estimated to be highest i.e. 46.60 plus minus 1.16 in Nick Chick laying hens. The anatomical variation in Desi and Fayoumi chicks was attributable to scavenging habit of these birds. The high proportion of edible offal in commercial Nick Chick hens may be ascribable to higher productive and reproductive traits.
اظهر المزيد [+] اقل [-]Studies on the thermostability of vero cell adapted rinderpest virus vaccine
2003
Asim, M. | Noor, M.S. | Zulfiqar, M. | Hussain, A. | Raza, M.A. (Veterinary Research Inst., Lahore (Pakistan))
This study was conducted to determine the optimum storage temperature for Rinderpest vaccine prepared on vero cells to know the shelf life of the vaccine. The vials were randomly selected from one batch of the vaccine, titrated and stored at minus 20 degree centigrade (Freezer), 4 degree centigrade (refrigerator) and room temperature. The titre was found to be 105.1 per ml. The vials stored at minus 20 degree centigrade & 4 degree centigrade were subjected to titration after an interval of six months for 3 and 2 years respectively. The vials stored at room temperature were tested after 4 weeks, 8 weeks and 12 weeks. Titration results indicated that the titre of the vaccine vials stored at room temperature decreased by 100.9 101.2 and 101.6 after storage time of 4 weeks, 8 weeks and 12 weeks respectively. The vials stored at 4 degree centigrade maintained their titre for a period of six months but after that the loss in titre was 100.4, 101.0, and 102.4 after storage time of one, one and half and two 2 years respectively. The vaccine vials stored at minus 20 degree centigrade maintained their original titres (initial titre of the vaccine) even after the storage for three years. It is concluded that vero cell adapted Rinderpest virus vaccine can be stored at 4 degree centigrade for a period of six months, however, at 20 degree centigrade it can be stored for three years without any adverse effect on titre.
اظهر المزيد [+] اقل [-]Recent advances in sheep breeding
2003
Hanif, M. (Directorate of Planning and Evaluation, Lahore (Pakistan)) | William, H.L.
The effects of melatonin and Light treatments on the reproductive performance of yearling Suffolk rams were investigated. The two groups (A, n = 8; B, n = 8) were given a priming period of long days (18 h Light (L): 6 h dark (D) during 1st February to 14th March. During 14th March to 9th September, group A was exposed to local light + melatonin Implants (Regulin) at 5 weekly intervals, group B was exposed to local light + melatonin Fed (M- 5250) alongwith the feed. The group (C, n = 8) in the local light during 1st February to 14th March and during 14th March to 9th September remained on local light + melatonin implants (Regulin) at 5-weekly intervals. However, the group (D, n=8) was treated as control and kept on local light environment (Lat. 51 degree 43'N) throughout the experiment. Testis diameter, sexual behaviours and semen quality were used to assess reproductive performances. The treatment to group A & B resulted in a significant advancement in high reproductive performance. The treatment to group C indicated that the abrupt application of melatonin in mid March resulted in a weak response in terms of all the criteria of assessment. The investigation indicated that seasonal fluctuations in reproductive behaviour and semen quality may be rephrased by the application of light and melatonin treatments and that these treatments may be considered for the preparation of rams for out of season breeding.
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