Comparison of plasma aldosterone concentration among clinical status groups of dogs with chronic heart failure

The plasma aldosterone concentration (PAC) among clinical status groups of 23 dogs with chronic heart failure was compared at various times after diagnosis of the problem. Eighteen dogs admitted in New York Heart Association (NYHA) class IV clinical status had significant elevations in PAC (P<0.0001), when compared with clinically normal dogs. Five dogs admitted in NYHA class III status and 4 dogs that responded with a change to NYHA class III status had significant elevations in PAC (P<0.01), when compared with clinically normal dogs. In patients with NYHA class IV status, the PAC was significantly greater (P<0.01) than in patients in NYHA class III status. For patients with the poorest prognosis, ie, severe signs of NYHA class IV status, the PAC was not markedly different, when compared with that for patients with a favorable prognosis, ie, recent onset of signs of NYHA class IV status. Patients treated with captopril had significantly lower PAC after therapy (P<0.01), whereas patients treated with hydralazine had significantly higher PAC (P<0.05) after therapy. It was concluded that heart failure in the dog increases PAC, most likely because of renin-angiotensin-aldosterone-system activation, and that the increase is related directly to the clinical status of the patient. Further, it was concluded that treatment of dogs in heart failure with captopril causes a decrease in circulating PAC, whereas treatment with hydralazine causes an increase in circulating PAC.     

Pathogenicity of various isolates of Alcaligenes faecalis for broilers

Day-old broilers or specific-pathogen-free chickens were inoculated intranasally with approximately 1 X 10(8) organisms of eight different field isolates of Alcaligenes faecalis. Major differences in the pathogenicity of isolates and their ability to colonize the trachea were found. Only two isolates (Wilson and Lockamy) produced mild clinical signs of respiratory disease ("snicking," dyspnea). The same two also colonized the respiratory tract, especially the trachea, in large numbers; they persisted for 31 days. Of the remaining six isolates, five were also able to colonize the respiratory tract but did so to a lesser degree and less persistently, without causing clinical signs. Only one isolate (CS) was incapable of becoming established in the respiratory tract of chicks after intranasal inoculation.     

Equine herpesvirus abortion in Australia 1977 to 1982

Until 1977 no case of abortion caused by equine herpesvirus 1 (EHV1) had been recorded in Australia although the virus, called equine rhinopneumonitis virus, had been known to have been present at least since 1962. Outbreaks of EHV1 abortion occurred in New South Wales in 1977 and in 1981. Sporadic cases of EHV1 abortion had been confirmed in some parts of Australia each year since 1975. It was concluded that an abortigenic subtype of EHV1 had been introduced to Australia in 1977 and that the previously endemic respiratory subtype occasionally caused abortion. Virus isolation in a variety of cell cultures and histopathological examination of tissue were shown to be satisfactory methods of diagnosis of EHV1 abortion. Lung proved to be the specimen of choice. Slight serological differences between "abortigenic" and "respiratory" subtypes of EHV1 were found in cross neutralisation tests. A serological survey of 219 Sydney horses of various ages revealed that most yearlings had already acquired neutralising antibody to both subtypes.     

The detection and measurement of stray electrical leakages on dairy farms: effects on performance

Sources of stray electrical leakage from Power Supply Authority alternating current (AC), fence energiser pulses and randomly generated pulses and spikes on 55 dairy farms in the Waikato area were identified between December 1986 and March 1988. The electrical measurements were made using a specifically designed voltmeter able to detect voltages between 0.1V and 1500V, from single voltage spikes of two microseconds or greater duration from direct current (DC) as well as 50 Hz AC. Ninety-five sources of stray voltage were identified, and 53 per cent of properties had more than one source of >0.5V. The major source was from electric fence energisers. Rotary platform parlours were among the commonest sources of random or transient voltage spikes. Leakage of AC into one or other of the components of the milk transport system such as vat, plate cooler, milk lift pump and milk line was common. Owners acknowledged the improvements in milk production, reproductive performance and growth rate of calves after reduction of the exposure of dairy cattle to stray electrical leakage. A representative summary of five case records helps define the range of improvements that may possibly be achieved.     

Organochlorine insecticide problems in livestock

1. Antidotal therapy for acute OC intoxications is symptomatic and supportive. Use sedatives to control convulsions and AC to adsorb any pesticide remaining in the gut, and wash topical exposures. 2. Published kinetics should be applied to field situations with caution. In general, residues decline relatively quickly immediately following the last exposure; thereafter, the rate slows considerably. The elimination-rate constant and, hence, the half-life of any given OC is dependent on many variables that usually are not known under field conditions. This fact may result in serious errors if literature values are relied on too heavily in predicting the outcome of "natural" contamination. As a rule of thumb, elimination data derived from animals experimentally fed to plateau concentrations may be regarded as fairly conservative for such purposes, if the contaminated animals are maintained in a normal fashion. Probably the least risky method of predicting return to marketability is using frequent samples, taken at regular intervals (for example, 1 to 2 weeks) during the first month after last exposure, to adjust literature values. 3. Residues from larger dosages and shorter exposures tend to be smaller in proportion to dose and are eliminated more quickly than those resulting from longer exposures and smaller doses. 4. Activated charcoal is of universal benefit only if given immediately after exposure. 5. Pharmaceutical modifiers of xenobiotic metabolism such as phenobarbital are of very limited value. The particular type and amount of residual OC and the potential economic benefit of therapy should be considered thoroughly before undertaking such therapy. In most cases, the expense won't be justified. 6. Mineral oil increases the fecal excretion of some OC. Fecal excretion, however, is so small in relation to total body burdens that even a several-fold increase may not be useful economically except when residue concentrations are low to start with. 7. Nutritional strategies have the advantage of being very cheap. Practitioners should remember, however, that tissue concentrations actually may increase as body fat decreases. The costs of maintaining animals for an extra 6 to 10 months should be considered before undertaking such an effort.(ABSTRACT TRUNCATED AT 400 WORDS)     

Neurotoxic syndrome of sheep due to the ingestion of plants of the Mediterranean scrub: clinical, histopathological, histochemical and ultrastructural observations

A severe neurological disorder was observed during a very dry season, in sheep pasturing on land with mediterranean vegetation. During the crisis, lasting 5-20", ataxia and convulsions were the main clinical signs. Brain congestion, spongy appearance of the liver, interstitial nephritis and hyperpigmentation of visceral lymph nodes were the most important macroscopic lesions. Histopathological, histochemical and ultrastructural findings confirmed liver and kidney lesions and showed considerable neurovisceral storage of lipofuscin. Although further toxicological and experimental studies are needed to elucidate the origin of the disease, the Authors attribute the outbreak of the neurological syndrome to the ingestion of a neurotoxin containing plant.