Webinar 4 Notes. Post-Mortem Guide

Transcription

1 Webinar 4 Notes Post-Mortem Guide 1. Examine the bird for any external injuries including vent pecking 2. Check for ectoparasites especially under the wing and around the vent 3. Check for vent pasting (faecal material/urates deposited around the vent) 4. Check the overall body condition and feather cover/quality 5. Place the bird in dorsal recumbency 6. Make an incision in the skin on the sternum and peel away 7. Dislocate both hips to improve stability (This also allows you to check the femoral head for infection) 8. Check the sciatic nerve for enlargement (which can be suggestive of Mareks) by parting the medial muscles on the femur 9. Check the body condition based upon the prominence of the breast bone (remember this varies considerably between breeds) 10. Look at the colour of the breast muscle (dark carcases are suggestive or dehydration or septicaemia) 11. Incise the lateral walls of the thorax and abdomen (some people prefer to remove the sternum and front of the rib cage entirely) 12. Observe the liver size- it should be no bigger than the rib cage (enlargement of the liver could suggest mareks, septicaemia or other bacterial infection) 13. Look at the colour of the liver (congested livers can be associated with septicaemia or heart failure. Spots on the liver can be due to Black head or bacterial foci) 14. Look at the air sacs: they should be clear and thin like cling film (any mucus/pus should be suggestive of respiratory disease. Such diseases can chronically thicken the air sacs and cause neovascularisation) 15. Next look at the lungs, which should be a nice salmon pink colour 16. Check the heart for pericarditis, hydropericardium and cardiomegaly 17. Lift up the liver and check the spleen (see below) (between the proventriculus and gizzard) for enlargement and congestion associated with infection

2 18. Check the abdomen for ascities and peritonitis 19. Incise the proventriculis and gizzard (below) to check for erosions and haemorrhage (note the gizzard should be full of stones to aid digestion) 20. Open the lumen of the intestines looking for haemorrhage inflammation and worms 21. Check the kidneys for enlargement

3 22. Next if female check to see if the bird is in lay and check the oviduct 23. Incise the crop to check its contents 24. Incise the lateral walls of the mouth to check for erosions 25. Cut across the caudal maxilla to check for sinusitis 26. Incise the trachea to check for inflammation 27. Finally incise the stifle and hock joints to check for synovitis

4 Sick Chicks There is nothing more natural than seeing a mother hen with her brood of chicks. However nature can be unpredictable and difficult to control and as such many backyard keepers turn to artificial incubation to hatch out birds. Brooding chicks can be a very rewarding process as owners get to watch their brood grow and play at close range. However correct brooding conditions are essential for a happy healthy brood. As with all neonates chicks require heat, light, food, water, bedding and most importantly cleanliness. Many owners are generally good about supplying food, water and heat but cleanliness and lighting are often neglected. The brooding pen should have straw or preferably shavings as a bedding. The brooding pen should be disinfected with a suitable disinfectant after a thorough cleaning with a detergent. Note if coccidiosis has been an issue for a previous batch then an anticoccidial disinfectant should be used. The area should be heated with either a heat lamp or a gas brooder. The ideal temperature for brooding is C for the first two days then decreased by 0.5 C thereafter. When chicks hatch out under a broody hen the mother hen will peck at food and encourage her chicks to eat. Under artificial conditions there is no such mentor to teach the chicks what to eat and drink so good quality lighting is essential so that they can adequately see their food and water. Next it is important to provide chicks with fresh water daily. Ensure owners clean the drinkers daily and that they are low enough for the chicks to drink out of and ensure that the chicks cant drown in them. Some people use the bottoms of old milk containers but these are light when empty and the chicks can tip them over and become trapped. Electrolytes can be added to the water for the first few days to encourage drinking and hydration. In their first week chicks should drink approximately 25 mls per day. Chicks should have fresh starter crumbs placed daily in clean appropriately sized troughs. In its first week a chick will eat around 90 grams of feed. Chicks should be fed feed appropriate to their agei.e. do not feed layers pellets or mash to day old chicks. Happy chicks will be eating, drinking, sleeping and making a low pitched cheeping sound. High pitched cheeping occurs when a chick isn t happy e.g. has been pecked by another chick or its environment isn t correct.

5 Common problems of newly hatched chicks The two most common problems of newly hatched chicks are starve-outs and yolk sac infections. Yolk sac infections are caused by bacteria (usually E. coli) getting into the yolk of the chick (which the chick has inside it for the first few days (3-5) of life as a food source). These bacteria can enter the shell through dirty shells especially from dirty eggs or from washing the eggs in dirty water before incubation. Bacteria can also enter the eggs during incubation through dirty incubators and hatchers. Finally the bacteria can enter the chicks navel after hatching. These chicks usually have a foul odour and mostly die within the first few days of life. They will usually have full crops as the infection takes a few days to take hold. Even if they survive they will often be stunted throughout life. Euthanasia is the best option as treatment is rarely successful. Post-mortem examination usually reveals congested yolk sacs (they should look like runny egg yolk) together with congested livers and spleens indicating bacteraemia. The other common problem with chicks are starve-outs. These are chicks that fail to learn to eat and drink and die after 4 days of age when their yolk sac runs out. For the first few days after hatching curiosity drives chicks to peck at objects and if they are of the correct particle size chicks will ingest them irrespective of whether or not they are food. After a few days of age this desire to peck diminishes and chicks eat due to hunger. If they haven t found food by then they will never learn to eat. There are many possible reasons for this- poor health of the parents, incorrect incubator settings and an incorrect brooding environment. Note: incorrect temperatures, insufficient lighting or too few drinkers and feeders can all contribute to starve-outs. As with yolk sac infection there is little in the way of effective treatment. The best option is to euthanize affected chicks as well as identifying and resolving the underlying factors. Post-mortem examination of affected birds will reveal urate deposits in their ureters due to dehydration together with enlarged gall bladders due to them not eating. White urate deposits in the kidneys of this non-starter chick

6 An inflamed infected yolk sac of a chick with yolk sac infection Aspergillus (Brooder Pneumonia) Brooder pneumonia is a re-emerging disease caused Aspergillus fumigatus. This fungus can be found in damp feed or bedding. Generally speaking spores are commonly found at low levels in poultry houses but rarely do they cause an issue except in certain circumstances: when the environment contains high levels of spores damp or mouldy feed or bedding immunosupressed birds young animals in environments with high spore levels such as day old chicks under brooders (hence the term brooder pneumonia). Traditionally some owners used damp bedding for their young birds. When the damp bedding was placed in the warm brooding environment the spore levels rose dramatically in incubators (these infected eggs can burst and release high levels of spores thus infecting the other chicks in the incubator) What to look out for: dyspnoeic birds which do not have increased respiratory sounds birds gasping in severe cases the nervous system becomes affected causing blindness, torticollis and/or paralysis

7 Diagnosis Diagnosis is generally based upon clinical signs and history. If birds have died a post-mortem together with fungal culture will be of use. In live animals radiography may aide diagnosis. Treatment: Once infected, birds will rarely recover as there is no suitable treatment (antifungals such as Itraconazole may be tried with varying degrees of success) Euthanasia should be considered try and identify the primary source of the spores (it s worth replacing the litter and feed) Fog the affected bird daily with F10 Prevention: The environment should have clean dry dust-free bedding such as bales of shavings The feed should be kept fresh, dust-free and dry The chick environment should be cleaned and disinfected between batches of chicks Never use hay to bed poultry. Several White Fungal Plaques caused by Aspergillus in the air sacs of this chick

8