VN June 2023

Vetnews | Junie 2023 35 Common Avian Clinical Problems Part 1 Dr Coetzee de Beer Malnutrition One of the most common, if not the most common, seen in clinical pet bird practice results from the feeding of exclusively or predominantly seed diets. Seed is often considered a ‘natural’ birds diet, but birds evolved long before the development of agricultural grain. Seed is high in:  Fat  Carbohydrates  Phosphorous Seed is low in:  Protein  Vitamins (except Vitamin E)  Calcium  Other minerals, e.g. zinc Feeding a high/all-seed diet results in a variety of disease syndromes  Hypovitaminosis A o Low Vitamin A results in hyperkeratinisation of the epithelial cells lining the upper respiratory tract, the upper gastrointestinal tract, and the ureters. This shortage predisposes these sites to secondary infections or causes dysfunction.  Hepatic lipidosis o The presentation of high dietary fat results in fat deposits in the liver. Eventually, severe liver disease and coagulopathies can develop.  Diabetes mellitus o Type II diabetes (insulin resistance) is common in middle-aged to older obese birds.  Cardiovascular disease o Atherosclerosis is commonly seen in many older birds with high dietary fat intake.  Nutritional secondary hyperparathyroidism o Metabolic bone disease is commonly seen in egg- laying hens and juveniles fed on all-seed diets.  Skin and feather dystrophies o Abnormal feather colour and structure, scaly pruritic skin and beak/nail overgrowth are often seen in long- termmalnourished birds.  Immunosuppression o Malnourished birds are more susceptible to infectious diseases than birds on a balanced diet. Chlamydiosis TheOrganism As of 2010, Chlamydiosis has been classified as a Gram-negative, non- motile, obligate intracellular bacteria of the Order Chlamydiales, Family Chlamydiaceae.There are two genera – Chlamydia and Chlamydophila. Chlamydia is the genera of veterinary interest. • Six Species are recognised: a. C. psittaci – birds, cattle, humans b. C. abortus – sheep, goats, cattle c. C. pneumoniae – humans, reptiles, amphibians, horses, koalas d. C. pecorum – ruminants & koalas e. C. felis – cats f. C. caviae – guinea pigs Chlamydia psittaci • Five serovars (A – E); different serovars infect specific species (eg A infects psittacines, E infects columbiformes). Psittacines are most frequently infected with serovar A (genotype A) strains but can also be infectedwith serovar B strains. Serovar A strains are considered to be highly pathogenic • Synonym: psittacosis, ornithosis • It has been a known zoonotic for about 100 years Clinical signs The virulence of the strain affects the clinical course, with clinical signs ranging from inapparent to severe septicaemia and acute death. Typically though, the disease affects either the respiratory tract, the gastrointestinal tract and liver, or both: • Respiratory signs • Conjunctivitis, often with loss or matting of peri-ocular feathers • Dyspnoea – tail bobbing, mouth-breathing • Sneezing o Purulent nasal discharge o Sinus distension • Gastrointestinal/hepatic signs o Diarrhoea o Biliverdinuria – green urates and urine o ‘Sick Bird Look’– fluffed, lethargic, anorexia, weight loss Technical I Article >>> 36 Feedingabalanceddiet is essential for thewell-beingof all birds. Modern-formulateddiets can takemuchof the guessworkout of aviannutritionbutshouldbesupplementedwithvegetablesand occasional fruit. Keep inmind that there is no single diet suitable for all species.