Western
Meeting of Poultry
Clinicians and Pathologists
|
Clinicians and Pathologists
|
|
A Study Into Leghorn Mortality J. Hanson and D. Onderka Veterinary Laboratory
In 1991, a field study investigating the incidence and causes of mortality in egg-type hen flocks was initiated. The project was suggested by the Alberta Egg Producers Board and the Board put in place funds for collection of birds from seven commercial production units in Alberta. These funds were matched by Alberta Agriculture Research Institute. Frank Robinson, of the University of Alberta, was responsible for initiation and coordination of the project. The Animal Health Lab in Edmonton provided the diagnostic work. Flock size varied among the seven flocks. Four flocks had 5000-9999, two flocks had 10,000 – 19,000, and one flock had 20,000 – 29,999 hens. A total of 81,300 hens were involved in the study. In all flocks, record of total mortality were kept and as much of the total mortality as possible was to be retained for submission to the provincial lab. Overall, the mortality rates ranged from 3.8% to 8.1% with a mean of 6.0%, 4860 birds died in the seven flocks and 1118 (23%) were submitted to the lab for diagnosis. Selected data is provided in the presentation. There was a small increase in the rate of submission during the first four months of the lay period. The major cause of mortality over the seven flocks was vent-picking trauma (27%, ranging from 9% to 44% of submissions). The second most common problem was an array of reproductive disorders (15%). The incidence was greater during the beginning and the end of the lay period. Other problems seen in order of decreasing incidence were emaciation/dehydration, fatty livers, leucosis, N.V.L. (including culling), nephrosis, other trauma, cage layer fatigue, miscellaneous tumours, and intestinal disorders. The project confirmed that non-infectious diseases are not significant as a major cause of mortality in the Alberta Layer industry. In some instances, individual farms had specific disease problems, such as leukosis, and fatty liver disease.
|
|
To send us your comments or questions regarding this web site, click here. |