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Biomedical subjects

D A Barr

Publications and source records attributed to D A Barr.

At least 37 records · Page 2Linked to original sources
PubMed1988

Influence of dietary electrolyte balance, source of added potassium and anticoccidial agents on the performance of male broilers.

1. The performance of 1680 male broiler chickens was measured from one to 42 d of age. They were given diets with three (125, 165 and 205 mEq/kg) electrolyte balances (sodium + potassium - chloride), two sources of added potassium (carbonate or sulphate) and two anticoccidial agents (90 mg/kg of either monensin or lasalocid). 2. The dietary treatments had no significant effects on the growth performance of broiler chickens in the starter phase. 3. In the finisher phase, the chickens given the diets containing lasalocid utilised food less efficiently that those given the diets containing monensin. 4. There were significant interactions between dietary electrolyte balance and source of added potassium on body weight gains and food:gain ratios in the finisher phase. In diets with an electrolyte balance of 205 mEq/kg, the inclusion of potassium sulphate instead of potassium carbonate increased body weight gains by 3.4% and reduced food:gain ratios by 4.6%. 5. The body weight gains of chickens given the finisher diets containing lasalocid and added potassium carbonate were reduced by 2.6% compared to those of chickens given the diets containing monensin or added potassium sulphate. 6. The litter moisture content was higher in pens with chickens on the diets with an electrolyte balance of 205 mEq/kg than on the diets with either 125 or 165 mEq/kg. Both lasalocid and potassium sulphate tended to increase the litter moisture content. 7. It may be concluded that the inclusion of 90 mg/kg of either monensin or lasalocid in broiler diets does not alter the balance of electrolytes required for optimum growth performance of broiler chickens.

Animals↗
PubMed1987

Pathogenicity studies with a strain of fowl adenovirus serotype 8 (VRI-33) in chickens.

Experiments were undertaken to study the pathogenesis of VRI-33, a strain of fowl adenovirus serotype 8 isolated from the liver of a broiler chicken with inclusion body hepatitis. A 30% death rate resulted from oral infection of one-day-old specific pathogen free chickens with 10(6) plaque forming units of VRI-33. Chickens 10, 14, 21 and 28 days of age did not die following infection via natural routes but there were some motalities following infection via parenteral routes. Immunodepression by neonatal cyclophosphamide treatment, followed by infection with VRI-33 via non-parenteral routes, caused varying degrees of hepatitis with basophilic intranuclear inclusion bodies in hepatocytes. The mortality rate of cyclophosphamide-treated, VRI-33 infected chickens, was not significantly altered by post-infection temperature stress. Infection with infectious bursal disease virus, followed by infection with VRI-33 via natural routes at 14 days of age, was not associated with mortalities.

Adenoviridae↗
PubMed1986

Diseases diagnosed in replacement layer and breeder chicken flocks in Victoria, Australia, 1977 to 1985.

During the period from July 1977 to June 1985, specimens from 766 replacement layer and breeder chicken flocks were submitted to the Veterinary Research Institute, Victoria, Australia, for investigation of morbidity, mortality and, or, poor performance. A total of 5940 necropsies, as well as numerous ancillary tests, were performed. The findings for these flocks are presented and the consequences of some particular diseases noted.

Animals↗
PubMed1986

Effect of dietary phosphorus concentration and electrolyte balance on the growth performance of broiler chickens.

The performance of 1680 male and female broiler chickens given diets with either a low (4.7-4.3 g/kg) or high (8.9-8.2 g/kg) content of inorganic phosphorus and four (150, 200, 250 and 300 mEq/kg) electrolyte balances (Na+K-Cl) was measured from 1-d-old to 49 d of age. Diets with the higher concentration of inorganic phosphorus reduced body weight gains in the starter (P less than 0.01) and finisher (P less than 0.05) phases but the efficiency of food utilisation was reduced only in the starter phase (P less than 0.05). The reduction in body weight gain was greater in males than in females. The growth depression caused by the higher concentration of inorganic phosphorus in the finisher diets was partially alleviated by increasing the electrolyte balance to either 250 or 300 mEq/kg diet. The higher concentration of inorganic phosphorus significantly reduced the dressing percentage and increased the abdominal fat pad weight and litter moisture content. Electrolyte balance had no significant effects on efficiency of food utilisation, abdominal fat pad weights or litter moisture content. Neither the dietary concentration of phosphorus nor the electrolyte balance had a significant effect on mortality or ash content of the tibia.

Animal Nutritional Physiological Phenomena↗
PubMed1986

The application of the ELISA to the diagnosis and control of avian encephalomyelitis.

An ELISA for measuring serum antibody against avian encephalomyelitis virus (AEV) was evaluated for its application to the diagnosis and control of avian encephalomyelitis (AE). A scoring system was developed for this ELISA (AE ELISA-Index) so that the overall level of antibody in the flock could be presented in a single, convenient number. During suspected outbreaks of disease thought to have been caused by AEV infection, the AE ELISA-Index increased in sequential serum samples. High levels of antibody against AEV were measured in 13 flocks experiencing egg productivity problems. Variable levels of antibody activity against infectious bronchitis virus (IBV) were also observed in 11 of these flocks. The AE ELISA-Index was correlated with the embryo susceptibility test. Application of the AE ELISA has indicated that natural exposure to the virus does not occur in all flocks, and vaccination failures were detected sufficiently early for revaccination to be administered before the onset of lay.

Animals↗
PubMed1985

Toxicity episodes involving agricultural chemicals and other substances in birds in Victoria, Australia.

A series of case reports detailing observations on toxicity episodes in birds caused by a variety of agricultural chemicals and other substances is presented. These problems arose as a result of ignorance, accident and malicious intent. The episodes involved maldison, monocrotophos, fenitrothion, trichlorofon, dieldrin, chlordane, endrin, metaldehyde, bromadiolone, arsenic, lead and zinc. An unresolved episode where toxicity was implicated is also included.

Animals↗
PubMed1985

Diseases diagnosed in broiler chicken flocks in Victoria, Australia, 1977 to 1984.

During the period July 1977 to June 1984, specimens from 1402 broiler chicken flocks were submitted to the Veterinary Research Institute, Victoria, Australia for investigation of morbidity, mortality and, or, poor performance. A total of 19,450 post mortem examinations, as well as numerous ancillary tests, were performed. The findings on these flocks are presented and the consequences of some particular diseases noted.

Anemia, Aplastic↗
PubMed1984

Field, clinical and pathological observations of a runting and stunting syndrome in broilers.

Observations on a runting and stunting syndrome in broiler chickens in Victoria, Australia, based on general observations from 1980 to 1983 on 2244 chickens from 109 affected broiler chicken flocks, are summarised. The details on 156 of these birds from five affected flocks with varying runting percentages are presented. Typically affected birds were presented with atrophy of the pancreas, the thymus and the bursa of Fabricius.

Animals↗
PubMed1984

Pancreatic degeneration in broilers with runting and stunting syndrome.

A number of plasma biochemical parameters were examined in five outbreaks of runting in broiler chickens. In four of the five outbreaks, runts showed consistent elevations in plasma amylase activity and reductions in glutathione peroxidase activity. In two of the five outbreaks the plasma vitamin E concentration was reduced, as was the activity of plasma alkaline phosphatase. A highly significant number of runted chickens were found to have pancreatic degeneration, elevated plasma amylase activity and reduced plasma glutathione peroxidase activity, compared with non-runted chickens. The implications of these changes are discussed in relation to the aetiology of runting and stunting syndrome and, in particular, the possible involvement of selenium.

Alkaline Phosphatase↗