The dispersal of Culicoides brevitarsis in eastern New South Wales and associations with the occurrences of arbovirus infections in cattle

Distributions of the vector Culicoides brevitarsis Kieffer (Diptera: Ceratopogonidae) (determined from light trap data) and 2 arboviruses (determined from seroconversions in sentinel cattle) were studied in eastern New South Wales in 1993–94. C brevitarsis was recorded progressively from endemic areas on the north coast, to Nowra on the south coast, and westward to Scone, in the Hunter Valley. C brevitarsis also survived through winter at Paterson, in the Hunter Valley. Its apparently focal reappearance in this marginal area had no obvious effect on the broad pattern of its progression or the dispersal of Akabane and bluetongue viruses. These viruses were first recorded from foci near Coffs Harbour, on the mid-north coast. Their first occurrences at different locations were associated with those of C brevitarsis, but not with each other. The viruses were found only within the recorded limits of the vector's distribution. Delays between the initial occurrence of C brevitarsis and first evidence of virus transmissions at locations ranged from 2 to 7 months. The delays decreased away from the points of focus and were negatively associated with the time of initial occurrence of the vector. Seroconversions to the viruses were related to the presence of C brevitarsis. However, the densities of C brevitarsis had no apparent effect on the initial numbers of cattle seroconverting to either virus. The results support the conclusion that the progressions of C brevitarsis and Akabane and bluetongue viruses were the result of gradual movements by the vector.     

Polyglandular endocrinopathy type II (Schmidt's syndrome) in a Dobermann pinscher

A three‐year‐old, female neutered, Dobermann pinscher was presented for investigation of lethargy, episodic collapse, ataxia and myxoedema. Primary hypothyroidism and primary cortisol‐deficient hypoadrenocorticism were diagnosed based on history, physical examination and compatible hormonal analysis. Increased serum concentrations of thyroglobulin autoantibodies and 21‐hydroxylase autoantibodies indicated an immune‐mediated aetiology. The case was complicated by lymphadenopathy with hand‐mirror lymphocytes, classically identified in lymphoma. A polymerase chain reaction test for antigen receptor rearrangement indicated polyclonality and therefore reactive lymphadenopathy. The dog's clinical signs resolved following introduction of levothyroxine and prednisolone. Prioritising the problem‐based approach in this case facilitated the diagnosis of hypoadrenocorticism in addition to hypothyroidism due to the persistence of clinical signs despite thyroxine replacement. Importantly, atypical adrenal gland dysfunction was not misinterpreted as inadequate therapeutic response to thyroxine supplementation. The observation that polyglandular endocrinopathy type II can occur in dogs suggests that in dogs with a suboptimal response to treatment for hypothyroidism or hypoadrenocorticism comorbid endocrinopathies should be investigated.     

Characterization of cattle of a five-breed diallel: VI. Fat deposition patterns of serially slaughtered bulls

Dissection and chemical analysis data from 197 bulls of 15 breedtypes were used to examine the distribution of total fat (TOTFAT) among carcass fat (CFAT), viscera fat (VIF), kidney plus pelvic fat (KPF) and blood fat (BLF). The bulls were obtained from a five-breed diallel involving Angus, Brahman, Hereford, Holstein and Jersey; reciprocal crosses were pooled. One or two bulls of each breedtype were slaughtered at each of seven ages: 6, 9, 12, 15, 18, 24 and 30 mo. An allometric equation was utilized to describe growth rate of each fat depot relative to either TOTFAT or carcass side weight (CSW). The pooled within-breedtype differential growth rates obtained from the allometric equation indicated that as TOTFAT or CSW increased, the proportion composed of CFAT and KPF increased (growth coefficients significantly greater than 1), whereas the proportion composed of VIF and BLF decreased (growth coefficients significantly less than 1). Holstein and Jersey tended to have more CFAT than Hereford, Angus and Brahman. Jersey had more KPF than other breeds. Crossbreds exhibited positive heterosis for CFAT and VIF, and negative heterosis for KPF. On a constant CSW basis, there were no significant breedtype differences in TOTFAT: nevertheless, differences in fat distribution among breedtypes persisted. There were different amounts of fat at the depots studied, but fat growth coefficients relative to TOTFAT tended to be homogeneous among breedtypes.     

Evaluation of production and reproduction of sheep, goat and alpaca genotypes in the Small Ruminant Collaborative Research Support Program

Research has been conducted as part of the Small Ruminant Collaborative Research Support Program (SR-CRSP) on evaluation of genetic resources and methods of effecting genetic improvement of small ruminants in the participating countries. In Kenya, the focus has been on development of a dual-purpose goat for milk and meat production in farming areas, utilizing two locally adapted breeds, Galla and East African, and two imported dairy breeds, Anglo-Nubian and Toggenburg, into a single stock. That research now has reached the stage of field testing. In Morocco, the performance of a highly prolific breed of sheep, the D'Man, and of a less prolific but larger breed, commonly raised under extensive management, the Sardi, and of their F1, F2 and backcross progeny has been evaluated for several reproduction and growth traits. Prolificacy of the D'Man was transmitted additively, but there was favorable heterosis for age at puberty, fertility and growth rate, resulting in substantial heterosis in total performance. In Indonesia, a high degree of variability in prolificacy in sheep appears to be due to segregation of a gene with large effect on ovulation rate, similar in some respects to the Booroola gene. In Peru, work has involved evaluation of effectiveness of current selection programs and estimation of phenotypic and genetic parameters, in unimproved and improved types of sheep, with a limited amount of work also on alpacas. Fiber production is the principal economic trait in alpacas. There also has been work on evaluation of hair sheep in Brazil, Kenya and Indonesia.     

IMAGING DIAGNOSIS—A CASE OF SPONTANEOUS HEPATIC PORTAL VEIN GAS IN AN 11‐MONTH‐OLD WEST HIGHLAND WHITE TERRIER

An 11‐month‐old female entire West Highland White Terrier presented for chronic diarrhea with acute deterioration in demeanor and progression to systemic inflammatory response syndrome. Transcutaneous abdominal ultrasonography identified colonic ulceration and secondary mucosal gas. Suspected hepatic portal vein gas and hepatic parenchyma gas were also visualized. The patient was stabilized and managed for ulcerative colitis. Based on endoscopic biopsies, the dog was diagnosed with severe, chronic, pyogranulomatous colitis. On repeat ultrasonographic evaluation the portal vein and hepatic gas had resolved but the patient deteriorated and was ultimately euthanized due to sepsis.     

The North American Animal Disease Spread Model: a simulation model to assist decision making in evaluating animal disease incursions

The North American Animal Disease Spread Model is a stochastic, spatial, state-transition simulation model for the spread of highly contagious diseases of animals. It was developed with broad international support to assist policy development and decision making involving disease incursions. User-established parameters define model behavior in terms of disease progression; disease spread by animal-to-animal contact, contact with contaminated personnel or equipment, and airborne dissemination; and the implementation of control measures such as destruction and vaccination. Resources available to implement disease control strategies, as well as the direct costs associated with these strategies, are taken into consideration. The model records a wide variety of measures of the extent of simulated outbreaks and other characteristics. The graphical interface and output visualization features also make it a useful tool for training and preparedness exercises. This model is now being used to evaluate outbreak scenarios and potential control strategies for several economically important exotic animal diseases in the United States, Canada, and elsewhere. NAADSM is freely available via the Internet at http://www.naadsm.org.     

Biological control of Phytophthora parasitica var. Nicotianae on tobacco seedlings with non-pathogenic binucleate Rhizoctonia fungi

Nonpathogenic binucleate Rhizoctonia fungi (BNR) controlled black shank caused by Phytophthora parasitica var. nicotianae on greenhouse-grown tobacco seedlings in styrofoam float trays. Three BNR isolates were incorporated into a soil-less mix on colonized, pulverized, sifted rice particles; colonized whole rice grains; or on pelleted tobacco seeds coated with 0.5% methyl cellulose. Five-wk-old seedlings were inoculated with zoospores of P. parasitica var. nicotianae and disease rated over 10 d. The level of protection varied with method of BNR application, ranging from 40 to 70%. Overall, control was better when BNR isolates were applied on rice inocula rather than on BNR-colonized tobacco seeds. From 15% to 80% of individual roots from seedlings grown in soil-less mix amended with BNR-colonized rice grains were colonized while only 0–20% of roots from seedlings grown from BNR-colonized tobacco seeds were colonized. Likewise, 37–100% of soil-less mix amended with BNR-colonized rice grains contained BNR's while less than 3% of soil-less mix was colonized when seedlings emerged from BNR-colonized tobacco seeds. This is the first demonstration of biocontrol of Phytophthora by BNR fungi.