Intra-farm variation of rodent infestations on poultry farms of central Argentina     

Gómez Villafañe IE  Cavia R  Busch M  Bilenca DN 《British poultry science》2003,44(5):669-673

1. During the summer and winter of 1998 we monitored rodent infestation in the sheds of 9 poultry farms in central Argentina to estimate variation in rodent infestation within farms and its possible association with shed structure and farm design. 2. We observed great heterogeneity in rodent infestations, with a mean variation of 37% in the 'Rodent Infestation Index' (RII; an estimate of rodent density revealed by tracks) between sheds of the same farm. 3. In summer, the group of sheds that showed the highest RII had a higher chicken density than the group of sheds with the lowest RII. Sheds located between other sheds of the same farm showed a lower RII than sheds located beside the perimeter of the farm. 4. Our results support the hypothesis that rodents show habitat selection at both macro (farm) and microhabitat (shed) scales, and that the variables associated with these associations can change according to the scale. 5. Our observation that sheds located beside the perimeter of the farms are prone to rodent invasions reinforces our previous recommendation that farms with an efficient control of vegetation growth around their perimeter would have appreciably lower rodent infestations.  相似文献   

Environmental and genetic variation of the effective radiative properties of the coat of Holstein cows under tropical conditions     

Alex Sandro Campos Maia  Roberto Gomes da Silva  Elaine Cristina Abaker Bertipaglia 《Livestock Production Science》2005,92(3):307-315

Morphological characteristics, coat effective radiative properties, and the percentage of white colour were measured in the coats of 973 Holstein cows, and estimates of the genetic parameters were obtained for these traits, except morphological characteristics. The results showed that white coats are more dense with long, thin hairs, while the black coats are less dense with short, thick hairs. Effective transmissivity is greater in the less-dense coats with short, thin hairs, independently of coat colour. Effective reflectivity depends more on the variation in the radiative properties of the coat and skin surface rather than on the morphological characteristics of the coat. Effective absorptivity is greater in black and dense coats with long, thick hairs, than in the white and less-dense coat with short, thin hairs. All heritability estimates were of low magnitude, except for the percentage of white coat colour.  相似文献   

Somatic embryogenesis and plant regeneration in Opuntia ficus-indica (L.) Mill. (Cactaceae)     

Francisco Linhares Arruda Ferreira Gomes  Fabíola Fernandes Heredia  Priscilla Barbeta e Silva  Olivardo Facó  Francisco de Assis de Paiva Campos 《Scientia Horticulturae》2006

We present here a method for the regeneration of the prickly-pear (Opuntia ficus-indica (L.) Mill.) through somatic embryogenesis (SE). Direct SE was induced by cultivating shoot apices devoid of leaf primordia on semisolid Murashige and Skoog (MS) basal medium supplemented with 4-amino 3,5,6-trichloropicolinic acid (picloram) at 4 mg l⁻¹. Somatic embryogenesis was influenced by the type, age, physiological and developmental stage of the explants, and also by light conditions, wounding, and the sucrose concentration in the induction medium. A histological analysis confirmed SE by revealing the presence of a closed vascular system in the developing embryos and the absence of a vascular connection between the somatic embryos and the explant.  相似文献   

Isolation of Staphylococcus schleiferi subspecies coagulans from two cases of canine pyoderma     

Bes M  Guérin-Faublée V  Freney J  Etienne J 《The Veterinary record》2002,150(15):487-488

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Investigation of putative CDT gene in Escherichia coli isolates from pigs with diarrhea     

da Silva AS  da Silva Leite D 《Veterinary microbiology》2002,89(2-3):195-199

In this study, 98 Escherichia coli isolates from 42 diarrheic neonatal piglets were screened for the presence of cytolethal distending toxin coding gene by polymerase chain reaction (PCR). PCR yielded a single product which was specifically generated for E. coli cdt(+) control strain and not for other control strains. Twenty two (22.4%) of the isolates tested were cdtB positive, and 50% of the cdtB(+) isolates were also estII positive. The most prevalent pathotype was O32 cdtB(+) estII(+), which accounted for 59% of the cdtB positive strains. These results indicate an association between the presence of the cdtB gene and diarrhea, and support the need for further studies to determine the role of this toxin in diarrhea.  相似文献   

Morphological aspects of the capybara stomach (Hydrochaeris hydrochaeris): gross and microscopic structure     

Moraes PT  Pacheco MR  de Souza WM  da Silva RA  Neto PB  Barreto CS  Ribeiro AA 《Anatomia, histologia, embryologia》2002,31(6):362-366

The digestive system of the capybara has been investigated because of its coprofagia habits, important for their absorptive activity. These species present differences in terms of gastrointestinal morphological characters when compared with other rodents. Macroscopiclly, the stomach of the capybara is constituted of the following parts: cardiac, pyloric, body, fundic and gastric diverticulum. It presents two curvatures, one big and another small. Externally, the presence of gastric bands (tenias) is observed. With regards to the volumetric view, the gastric capacity varies from 850 to 2010 ml, with an average of 1498.57 ml. So, the stomach of this animal can be classified as a simple stomach, in the format of a curved sack and similar to an inverted letter 'J'. The gastric mucous membrane presents a surface filled by numerous tortuous gastric folds and longitudinally distributed along all its extension. The mucous tunic also possesses recesses located among the successive gastric folds, which were denoted as gastric parts with numerous openings described as gastric pits. In the cardiac part, a glandular epithelium with cardiac glands is noticed containing a lot of parietal and mucous neck cells. The fundic part, body and gastric diverticulum contain proper gastric glands with main, parietal and mucous neck cells. Finally, the pyloric part has pyloric glands with two cellular types, mucous neck and parietal cells.  相似文献   

Escherichia coli heat-stable enterotoxin b (STb) in vivo internalization within rat intestinal epithelial cells     

Labrie V  Harel J  Dubreuil JD 《Veterinary research》2002,33(2):223-228

Heat-stable enterotoxin b (STb) is a low molecular weight toxin known to bind sulfatide, its receptor. The fate of STb bound to rat intestinal epithelium cells was followed using an anti-toxin gold labeled assay and transmission electron microscopy. The data suggest that STb toxin and the fusion protein maltose binding protein (MBP)-STb were internalized whereas its mutant I41 E-M42R with reduced hydrophobicity did not show internalization. There was a significant difference in the mean of gold particles per field between rat intestine incubated with STb or the fusion protein MBP-STb and the negative control consisting of intestine incubated with PBS alone. No subcellular compartment seems to be particularly aimed by the toxin as gold particles were randomly distributed within the cell.  相似文献   

PREVALENCE OF GALLBLADDER SLUDGE IN DOGS AS ASSESSED BY ULTRASONOGRAPHY     

Catharina  Brömel  DR. MED.VET  Paul Y.  Barthez  DVM  Renée  Léveillé  DVM  Peter V.  Scrivani  DVM 《Veterinary radiology & ultrasound》1998,39(3):206-21

Ultrasonography of the gallbladder was performed in 3 groups of dogs: 30 clinically healthy dogs, 50 dogs with hepatobiliary disease, and 50 dogs with diseases other than hepatobiliary disease. The gallbladder was evaluated for the presence of sludge (echogenic material without acoustic shadowing). Maximal gallbladder length, width, height, and area were measured as well as the gallbladder wall thickness. The relative sludge area was calculated as the ratio of sludge area over gallbladder area on longitudinal images. No significant difference was found in the prevalence of gallbladder sludge among healthy dogs (53%), dogs with hepatobiliary diseases (62%), and dogs with other disease (48%). The mean age of dogs with sludge was higher than the mean age of dogs without sludge in dogs with hepatobiliary disease and dogs with other diseases (p ≤0.05). The mean relative sludge area did not differ significantly among the 3 groups. A trend to larger gallbladder dimensions in dogs with sludge compared to dogs without sludge was detected within the 3 groups. The gallbladder wall thickness was not different between dogs with and without sludge within the 3 groups. However, the gallbladder wall was more frequently isoechoic than hyperechoic to the liver in dogs with sludge than in dogs without sludge. The results of this study indicate that gallbladder sludge, in dogs, in not particularly associated with hepatobiliary disease and should be considered an incidental finding.  相似文献   

Seroepidemiology of rinderpest in bovids in Sri Lanka using the enzyme linked immunosorbent assay (ELISA) technique     

Indira Silva  Ashoka Dangolla  John Allen 《Preventive veterinary medicine》1998,37(1-4):69-75

Approximately 0.2% (n=4397) of the bovids (cattle and buffalo) in Sri Lanka were sampled, from June 1992 using a multi-stage sampling procedure. Serum antibodies for the rinderpest virus were detected using the competitive enzyme-linked immunosorbent assay. The age, the agroclimatic zone, the management system practiced in the farms, and the vaccination history of the sampled bovids were studied as potential risk factors for being seropositive.

The prevalence of rinderpest antibodies in non-vaccinated bovids was 3.5% (n=4101). The prevalence was higher in the dry zone (9%; where the outbreak emerged in 1987), compared to bovids in the other zones (1%). Seropositive bovids over three years of age were approximately at fourfold higher chances of being seropositive compared to those that were ≤3 years old. The higher prevalence in older animals is probably due to exposure to the virus during the 1987 epidemic. Bovids from the dry zone (annual rainfall 20 to 35 inches) were at higher odds of being seropositive even after controlling for the possible effects of age, agroclimatic zone, management system and vaccination. The fact that 62% of bovids from the dry zone in this study were reared under extensive management system (free grazing) which allow unrestricted contact between animals, may be the reason for the above finding. A relatively poor response to vaccination observed in vaccinated bovids (seroprevalence=12%; n=296) could be attributed to difficulties in maintaining the vaccine at recommended temperatures in the field. This is the first island-wide study on seroprevalence of rinderpest in Sri Lanka.  相似文献   

油桃新品种‘中油桃4 号’     

王志强  刘淑娥  牛良  宗学普  宋银花 《园艺学报》2003,30(5):631-631

 ‘中油桃4 号’是通过有性杂交育成的早熟、优质、抗裂油桃新品种。果实椭圆形至近圆形,单果质量116～145 g , 果面全红, 艳丽美观。果肉黄, 可溶性固形物11 %～15 % , 品质优。果实发育期72 d。丰产。  相似文献