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This article was published in 1957
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.
Haemorrhagic Disease in Chickens
M. LINDTNER, D.V.M., Veterinary Research Station, Glenfield.
Haemorrhagic Disease is a pathological condition of young chickens 3-10 weeks of age; characterised by haemorrhages, anaemia and degenerated bone marrow. The incidence of this disease is fairly low and seems to affect only the birds under industrial feeding conditions.
The course of the disease runs for approximately 14 days, with the maximum mortality of 1-40% at the end of this period, and fades away gradually with a fairly slow recovery.
It is not infectious and cannot be transmitted. Although not considered of any major economical importance, an incorrect diagnosis can complicate its course and reverse its usually favourable resolution.
Haemorrhagic Disease appears in the flock with sudden, rather rapidly increasing cases of mortality without much change in general appearance and food consumption of the rest. Inspection of affected birds will show some symptoms varying in degree; related to internal lesions observed later as post-mortem. Basically, Haemorrhagic Disease is a certain, not yet completely understood, pathological condition of bone marrow and blood in which normal prcess of blood-clot formation is markedly retarded. So any haemorrhage produced in bird tissue, whether by external injury (wing binding, toe punching, cannibalism, pox vaccination,etc.) or internal causes (contusions, Coccidiosis, toxic substances,etc.), will continue to bleed for a length of time sufficient to produce irreparable damage to the organism.
The failure of clotting mechanisms could be observed by laboratory technique in which the delay of clot formation normally from 1.8-2.4 minutes up to 90 minutes is observed; which explains the reasons for fatality in some birds.
Beside the external and internal causes of haemorrhage it has been found that the altered blood itself also possess a certain destructive action on the cells of small vessel walls; producing the appearance of spontaneous haemorrhages in any organ.
It was discovered that the lack of Vitamin K may play a major part in this pathological condition.
Understanding the above basic principles and applying them in examination, any symptomatology in birds will be interpreted easily.
Sick birds appear anaemic, weak and listless. Haemorrhages of varying degree will be found in subcutaneous tissue of wings, legs and also in anterior chamber of the eyes. They may show blood-stained diarrhoea in the cases in which the haemorrhages originate from the intestine. At P.M. haemorrhages ranging in size from pin-points up to larger areas, may be found in any tissue or organ. In pectoral or other skeletal muscles, heart, kidneys, proventriculus and under the lining membrane of gizzard. In the early stages the haemorrhages are red, but later when the necrotic process takes over, larger greyish areas can be observed.
Intestines may present circular haemorrhagic spots up to 4 mm. in diameter, particularly in duodenum, and mass pin-point haemorrhages in lower part of intestine. Such a haemorrhagic enteritis may later develop into ulcerative enteritis, even with perforations.
The examination of bone marrow should never be omitted; its appearance is of most important diagnostic value. Cutting along the femur or tibia, the bone marrow is exposed and its colour judged. Healthy marrow is cherry red in colour; whereas in Haemorrhagic Disease it is greyish-yellow. This colour is due to degeneration of bone marrow cells, which are replaced gradually by fatty tissue.
Such a bone marrow is naturally out of function and the production of fresh red cells of blood ceases. The number of red cells in the blood is reduced rapidly: causing anaemia which can be aggravated by loss of blood through haemorrhages.
The Haemorrhagic Disease which has been discussed here is a condition due to Vitamin K deficiency. This Vitamin K, or anti-haemorrhagic, is contained in green leaves of various vegetables (peas, carrots, spinach, cauliflower, cabbage,etc.), cereals and grasses; particularly those rich in leaves directly exposed to the sun's rays. It is stable and remains active also after the drying process. Fish meal is also a rich source of Vitamin K. Various bacteria in the intestinal tract produce a certain amount of Vitamin K which combined with the plant supply, suffices the needs of the bird.
Vitamin K is transmitted through eggs and the hens, being fed on Vitamin K deficient diet, hatch out chickens which develop the haemorrhagic syndrome as early as five days of age. The hen's ration should contain at least 2.5% of cereal grasses in mash.
Vitamin K also is produced synthetically and could be administered by mouth or by injection.
Before deciding on a diagnosis of Haemorrhagic Disease, consideration must be given to many other diseases which present similar haemorrhagic symptoms. For instance:
1. Coccidiosis is often responsible for incorrect diagnosis, particularly when the haemorrhagic lesions in the intestine due to Vitamin K deficiency are very prominent. Examination of intestinal smear for detection of Coccidia and examination of bone marrow, which remains red in cases of Coccidiosis, will clear the situation.
2. Sulphaquinoxalin poisoning due to prolonged treatment for Coccidiosis, if given in repeated high doses of 0.4% for 14 days, will produce lesions easily mistaken for Haemorrhagic Disease. However, the lesions in this case are haemorrhages mostly localised around the kidneys, although they can be found elsewhere. Bone marrow is not very much affected. Withholding the Sulphaquinoxalin intake and giving an abundant supply of green feed or synthetic Vitamin K will improve the condition. Here is the reason why the differential diagnosis of Coccidiosis is of such importance. If the birds are affected with Vitamin K deficiency and by mistake the diagnosis of Coccidiosis is made, treatment with Sulphaquinoxalin will antagonise the Vitamin K, so aggravation of the condition will result and complicate the whole outcome of the disease.
3. Vitamin E deficiency usually presents symptoms in chickens of the condition known as "crazy chick disease", but often the extensive haemorrhages in the subcutaneous tissue and abdominal cavity or intestines can be observed. Bone marrow is not affected and supply of peanut oil will rapidly correct the condition of the Flock.
4. Prolonged treatment with antibiotics and sulpha drugs will destroy this source of Vitamin K production and become a trigger factor for the onset of Haemorrhagic Disease; particularly if Vitamin K is missing from the diet.
5. Dicumerol (Rat poison) poisoning shows a very pronounced haemorrhagic P.M.picture. However, the haemorrhages are spread equally through whole areas in the organs or intestines; accompanied by general congestion of tisues. Bone marrow is red and the history as to whether the birds have ingested rat poison will simplify the differentation.
6. Other factors, such as low sulphur content of fishmeal, Trichlorethylene extracted soy bean meal, mould toxins in feed or litter, nicotine and analine substances, are also responsible for haemorrhagic symptomatology, but are of such a rare incidence that they have no practical value in the field.
Examining the incidence of Haemorrhagic Disease in chickens from the statistical angle, it will be noted that the occurrence of this condition is nearly always associated with preventative Sulphaquinoxalin treatment. Such information gathered from the history of an outbreak could be very valuable for diagnosis and will point out the procedure of treatment.
Abstention from any drugs or antibiotics, abundant green feed supply and administration of synthetic Vitamin K orally or by intramuscular injections will bring about the recovery of the birds in a few days, provided they have not yet become grossly affected.