A syndrome of pathological fractures in the proximal tibiotarsi of White Leghorn x New Hampshire pullets.
A condition causing lameness was found in 22 five to 8-week-old New Hampshire x White Leghorn pullets, which represented about 10% of the flock. Examination of the proximal tibiotarsi revealed bilateral transverse lines of necrosis just below the growth plates. Histologically, the growth plate was widened and thickened, and irregular. Fibroplasia, an increase in osteoclasts and an infiltration with heterophils was present at the line of necrosis. There was marked lymphoid hypertrophy in the metaphsis distal to the areas of necrosis. The condition was probably due to collapse of trabeculae. Over 2,000 other pullets of the same age, some of which had more rapid growth rates, were reared on the same feed but were not clinically affected. There were some similarities between this condition and Moller-Barlow disease (vitamin C deficiency) which occurs in young children and other mammalian species.
Reece
R L
RL
Department of Agriculture and Rural Affairs, Veterinary Research Institute, Parkville, Victoria, Australia.
Dickson
D B
DB