Evidence for freedom from Johne's disease in cattle and goats in Western Australia   总被引：1，自引：0，他引：1  

TM ELLIS  RT NORRIS  PAJ MARTIN  RH CASEY  CD HAWKINS 《Australian veterinary journal》1998,76(9):630-633

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Genetic diversity of feral alfalfa (<Emphasis Type="Italic">Medicago</Emphasis> <Emphasis Type="Italic">sativa</Emphasis> L.) populations occurring in Manitoba,Canada and comparison with alfalfa cultivars: an analysis using SSR markers and phenotypic traits     

M. V. Bagavathiannan  B. Julier  P. Barre  R. H. Gulden  R. C. Van Acker 《Euphytica》2010,173(3):419-432

Feral populations of cultivated crops may act as reservoirs for novel traits and aid in trait movement across the landscape. Knowledge on the genetic diversity of feral populations may provide new insights into their origin and evolution and may help in the design of efficient novel trait confinement protocols. In this study, the genetic diversity of 12 feral alfalfa (Medicago sativa) populations originating from southern Manitoba (Canada) and 10 alfalfa cultivars and a M. falcata germplasm were investigated using eight SSR markers (i.e., microsatellites) and 14 phenotypic traits. We found that the genetic diversity observed in feral populations was similar to the diversity detected among the 10 cultivars. Analysis of molecular variance revealed that there was great genetic variation within (99.8%) rather than between different feral populations. Cluster analysis (unweighted pair-group method using arithmetic average) revealed no differentiation between feral populations and cultivars for neutral loci. High levels of population differentiation for phenotypic traits (and not for neutral markers) suggest the occurrence of heterogeneous selection for adaptive traits. The phenotypic traits we studied did not distinctly separate feral populations from cultivars but there was evidence of natural selection in feral populations for traits including winter survivability, rhizome production, and prostrate growth habit. Our results suggest that feral alfalfa populations need to be considered in the risk assessment of alfalfa containing novel genetically modified (GM) traits. Further, feral alfalfa populations may be regarded as a source of new germplasm for plant improvement.  相似文献   

Active Immunization against Gonadotrophin-releasing Hormone in Chinese Male Pigs   总被引：1，自引：0，他引：1  

XY Zeng  JA Turkstra  DFM van de Wiel  DZ Guo  XY Liu  RH Meloen  WMM Schaaper  FQ Chen  HB Oonk  & X Zhang 《Reproduction in domestic animals》2001,36(2):101-105

We have investigated, under the normal conditions of local Chinese pig farming, castration of young male pigs by vaccination with a newly developed vaccine against gonadotrophin releasing hormone (GnRH). Because of the very early onset of puberty, long fattening period and relatively harsh circumstances in Chinese pig production, an investigation of the endocrine response of Chinese breeds to this type of vaccination was of particular interest. Fifteen crossbred boars (Yorkshire × Yanan) from three different litters were randomly assigned to three groups of five animals each. The first group was immunized at 13 weeks of age with a GnRH tandem dimer OVA‐conjugate in Specol and received a booster immunization 8 weeks later. The second group was injected with Specol alone and served as untreated controls. The remaining group was surgically castrated at the time of weaning (at 6 weeks of age). Pigs were fed ad libitum from weaning onwards. All animals were slaughtered at 31 weeks of age. Immunized boars had undetectable or low serum testosterone (0.09 ± 0.12 ng/ml), low fat androstenone (0.05 ± 0.01 μg/g) levels and very low testes weights (19.1 ± 4.3 g). Intact controls had much higher serum levels of testosterone (9.76 ± 4.81 ng/ml), fat androstenone levels (2.26 ± 0.87 μg/g) and testes weights (114.3 ± 29.41 g) at slaughter. Both the immunized and castrated group grew significantly faster than intact boars (p < 0.01). Average daily gains in immunized, castrated and intact animals were 0.69 ± 0.08, 0.63 ± 0.05 and 0.42 ± 0.07 kg (mean ± SD), respectively. The present data demonstrate for the first time that the newly developed anti‐GnRH vaccine works very well under practical Chinese pig farming conditions, and can be an attractive alternative to surgical castration.  相似文献   

The effects of allopurinol on the ultrastructure of ischaemic and reperfused large intestine of sheep   总被引：1，自引：0，他引：1  

M AHMADINEJAD  MAE REX  RH SUTTON  CC POLLITT  B CRIBB 《Australian veterinary journal》1996,74(2):135-139

Objective To test the possible inhibitory effect of allopurinol on reperfusion injury, caused by oxygen-derived free radicals, of sheep large intestine.
Design An ultrastructural study on caecal tissues from control and treated groups.  

Animals

Fifty sheep in four ischaemic and reperfused (treatment) groups and one control group. Three of the treatment groups were subdivided for half to be injected with allopurinol and the other half with its solvent, potassium hydroxide (KOH).
Procedure Ischaemia of the caecum was induced in the four treatment groups for 60 minutes by clamping the apex. Allopurinol and its KOH solvent were injected intravenously in three treatment groups prior to ischaemia. Samples were collected before and 1 hour after induction of ischaemia and 1 min, 1 h and 8 h after reperfusion. Tissues were processed and examined with an electron microscope.
Results Untreated and solvent injected sheep showed minor ultrastructural changes following ischaemia. With reperfusion, there was severe mitochondrial, goblet cell and basement membrane damage. Tissues from allopurinoltreated sheep were preserved and appeared similar to tissues from the control group.  

Conclusion:

Pre-treatment with allopurinol prevented damage to tissues whereas untreated or allopurinol solventtreated showed severe damage following reperfusion. It is believed that allopurinol, an analogue of hypoxanthine and xanthine, prevents reperfusion injury by competitively binding with xanthine oxidase. This reduces or inhibits the xanthine oxidase mediated conversion of hypoxanthine to xanthine thereby preventing the formation of oxygen-derived free radicals.  相似文献   

Relative contribution of genotype, seed size and environment to secondary seed dormancy potential in Canadian spring oilseed rape (Brassica napus)     

R H Gulden  A G Thomas†  & S J Shirtliffe 《Weed Research》2004,44(2):97-106

Secondary seed dormancy has been linked to seedbank persistence of volunteer oilseed rape (Brassica napus) in western Canada. It has been suggested that there is a genetic component to secondary seed dormancy expression in oilseed rape, but little is known of its importance in relation to non‐genetic factors. In a series of experiments we investigated the relative importance of genotype, seed size, time of windrowing and pre‐ and post‐harvest environment on the expression of secondary seed dormancy. We found that genotype contributed between 44 and 82% to the total variation in secondary seed dormancy. A broad range in secondary seed dormancy expression was observed among 16 genotypes examined. Nevertheless, three‐quarters of the genotypes investigated exhibited relatively high potential for the expression of secondary seed dormancy (back‐transformed mean 71% dormant seeds). Seed size contributed 21% to the total variation, while the influence of seed maturity (harvest regime) on secondary seed dormancy expression was negligible. Despite diverging environmental conditions during the four growing seasons spanning these experiments, the influence of pre‐harvest environment on seed dormancy expression was relatively small and ranged from 0.1% to 4.5%. Secondary seed dormancy potential decreased over time during seed storage. This decrease was greatest when seeds were stored at ambient temperatures and least when seeds were stored at ?70°C.  相似文献   

ULTRASONOGRAPHIC APPEARANCE AND CLINICAL FINDINGS IN 14 DOGS WITH GALLBLADDER MUCOCELE     

JG Besso  DEDV  RH Wrigley  BVSc  MS DVR  JM Gliatto  VMD CRL Webster  DVM 《Veterinary radiology & ultrasound》2000,41(3):261-271

Fourteen dogs with enlarged gallbladders and immobile stellate or finely striated bile patterns on ultrasound are described. Smaller breeds and older dogs were overrepresented, with 4/14 Cocker Spaniels. Most dogs presented for nonspecific clinical signs such as vomiting, anorexia and lethargy. Abdominal pain, icterus and hyperthermia were the most common findings on physical examination. All dogs except one had serum elevation of total bilirubin and/or alkaline phosphatase, alanine aminotransferase and gamma glutamyl transferase. All dogs were diagnosed with a gallbladder mucocele upon histologic and/or macroscopic evaluation. Ultrasonographically, mucoceles are characterized by the appearance of the stellate or finely striated bile patterns and differ from biliary sludge by the absence of gravity dependent bile movement. On ultrasound, gallbladder wall thickness and wall appearance were variable and nonspecific. The cystic or common bile duct were normal sized in 5 dogs although all 5 had evidence of biliary obstruction at surgery or necropsy. Loss of gallbladder wall integrity and/or gallbladder rupture were present in 50% of the dogs, all located in the fundus. Gallbladder wall discontinuity on ultrasound indicated rupture whereas neither bile patterns predicted the likelihood of gallbladder rupture. Pericholecystic hyperechoic fat or fluid were suggestive of but not diagnostic for a gallbladder rupture. Cholecystectomy appears to be an appropriate treatment for mucoceles, if not to treat a gallbladder rupture, at least in most dogs to prevent it since gallbladder wall necrosis was identified by histology in 9 of 10 dogs. Mucosal hyperplasia was present in all gallbladders examined histologically. Positive aerobic bacterial culture was obtained from bile in 6 of 9 dogs. Cholecystitis was diagnosed histologically in 5 dogs and 4 dogs had signs of gallbladder infection solely upon bacterial bile culture. Gallbladder infection was not present with all the mucoceles suggesting that biliary stasis and mucosal hyperplasia may be the primary factors involved in mucocele formation. Based on the results of our study, we suggest two alternate courses of action in the presence of a distended gallbladder with an immobile ultrasonographic stellate or finely striated bile pattern: a cholecystectomy when clinical or biochemical signs of hepatobiliary disease are present or a medical treatment (antibiotics and choleretics) and patient monitoring by follow-up ultrasound examinations when the patient does not have clinical or biochemical abnormalities. An aerobic bile culture should be obtained in all patients, by ultrasound-guided fine needle aspirate or at surgery.  相似文献   

Development of Reproductive System and Levels of Sexual Hormones in Blood Plasma in Chinese Hu Sheep Ewe Lambs     

GH Yue  CX Xie  RH Cheng 《Reproduction in domestic animals》1996,31(3):725-728

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Antibiotic prophylaxis of lower respiratory tract contamination in horses confined with head elevation for 24 or 48 hours     

SL RAIDAL  RH TAPLIN  GD BAILEY  DN LOVE 《Australian veterinary journal》1997,75(2):126-131

Objective To evaluate the administration of procaine penicillin prior to or during confinement with head elevation as a means of reducing the associated accumulation of inflammatory lower respiratory tract secretions and increased numbers of bacteria within the lower respiratory tract of confined horses. Design and Procedure Two experiments were conducted to evaluate the efficacy of different dose rates and dosing frequencies. In experiment A a single low dose (15,000 IU/kg) of procaine penicillin was administered to four horses immediately prior to confinement with head elevation for 48 hours. The systemic leucocyte response, gross and cytologic characteristics of transtracheal aspirate and bacterial numbers in lower respiratory tract samples were compared with corresponding samples from two horses confined with heads elevated but not given penicillin. The efficacy of higher dose rates (20,000 IU/kg and 40,000 IU/kg) given before and during confinement with heads elevated for 24 hours was evaluated in experiment B. Results Treatment with procaine penicillin had no effect on the systemic leucocyte response or on the accumulation of inflammatory lower respiratory tract secretions at any of the dosing schedules evaluated. The number of bacteria isolated from trans-tracheal samples was reduced at 12 hours for treated horses in experiment A and at 24 hours for experiment B. β-haemolytic Streptococcus spp were not isolated from treated horses in either experiment. Bacterial species isolated from treated horses were predominantly Pasteurella and/or Actinobacillus spp, however, members of the family Enterobacteriaceaé and a Staphylococcus sp were isolated from treated horses. One treated horse in experiment A developed clinically apparent pulmonary disease. Conclusions The prophylactic administration of penicillin before or during confinement did not reliably reduce bacterial numbers or prevent the accumulation of purulent lower respiratory tract secretions in horses confined with their heads elevated. Numbers of β-haemolytic Streptococcus spp were reduced following treatment, suggesting that the repeated administration of procaine penicillin may have some merit as part of a strategy to prevent transport-associated respiratory disease. However, methods directed at minimising the duration of confinement with head elevation, augmentation of the clearance of accumulated secretions and prompt identification of animals in which airway inflammation has extended to the pulmonary parenchyma remain the best ways of minimising transport-associated respiratory disease.  相似文献   

The detection of lice (Bovicola ovis) in mobs of sheep: a comparison of fleece parting, the lamp test and the table locks test     

PW MORCOMBE  GE YOUNG  MD BALL†  RH DUNLOP† 《Australian veterinary journal》1996,73(5):170-173

Knowledge of the presence or absence of lice in a flock of sheep enables wool growers to make informed decisions as to the need for insecticidal treatments. However, with inapparent infestations, traditional methods of detection are not sufficiently sensitive and, as a consequence, flocks may be left untreated. Conversely, the routine application of insecticide to sheep with no sign of infestation is an unnecessary cost. The sensitivity of 3 procedures for detecting lice was evaluated in 68 mobs of sheep from 50 farms. In 24 mobs of sheep known to be lightly infested, lice were detected in 17% by either parting the fleece of 10 sheep or by the lamp test in which 8 g samples of shorn wool from 30 randomly selected fleeces were placed under lamps for 10 min to repel the lice. Twenty of 23 mobs (87%) were found to be infested by the table locks test in which a 30 g sample of locks wool was dissolved in 10% sodium hydroxide and the filtered residue examined with x 40 magnification. A screening test, in which either fleeces on 5 sheep were examined by fleece parting or lice were repelled from 30 shorn fleeces for 5 minutes, detected about 60% of lightly infested mobs. When this was followed by the table locks test 91% of lightly infested mobs were detected. Conducting any one of the tests on more than one mob, and in large mobs testing more frequently, increases the sensitivity of detection of lice within the whole flock.  相似文献   

A survey of skin neoplasms in dogs from the Brisbane region     

JC ER  RH SUTTON 《Australian veterinary journal》1989,66(7):225-227

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