The oncogenic potential of eleven avian adenovirus strains.

Oncogenic potentials of 11 strains of avian adenovirus representing 10 serotypes were investigated in 22 litters of 1-day-old Syrian hamsters (Mesocricetus auratus). Hamsters were inoculated via two routes: subcutaneous dose of 0.12 ml and intracerebral dose of 0.02 ml. Six strains, Indiana-C (Ind-C), chicken embryo lethal orphan (CELO), Stein, 75-1A, B-3, and A-2, induced fibrosarcomas subcutaneously at the inoculation site. Hamsters inoculated intracerebrally with Ind-C, CELO, Stein, B-3, and A-2 developed carcinomas of the choroid plexus. Strain 75-1A virus produced tumors on subcutaneous inoculation but failed to produce tumors on intracerebral inoculation. The Tipton, J-2, T-8, C-2B, and X-11 strains did not produce tumors in hamsters. Uninoculated control hamsters did not develop tumors.

Two outbreaks of colibacillosis in commercial caged layers.

A severe septicemia of Escherichia coli etiology was diagnosed in two houses containing 51,570 and 76,200 layers with mortalities of 6.83% and 4.27%, respectively. Dead birds were removed every other day; however, on occasion, gathering was done on the third day. The disease started in 22-wk-old pullets, and 3 wk later was diagnosed in 82-wk-old birds in an adjoining house. The duration of mortality in house 1 was 12 wk and in house 2 was 13 wk. A non-lactose-fermenting E. coli was isolated. Another outbreak of colibacillosis was diagnosed with 7.8% mortality at a different farm containing 47,000 110-wk-old hens and 10,000 40-wk-old pullets. On this farm the duration of mortality was not provided. Antibiotic treatment failed to reduce losses; chlorine added to the drinking water was effective in controlling the spread of disease and in reducing mortality at both farms.

Effect of particle size of the calcium source on performance of broiler chicks fed diets with different calcium and phosphorus levels.

Broiler chicks were fed diets differing in calcium (Ca) level, source, and particle size. The basal diet fed in most experiments contained .62% total phosphorus and .49% Ca from sources other than the Ca sources being compared. Performance was not affected by Ca source in diets with .9% Ca. In diets with 1.5% Ca, gain and bone ash were significantly lower with a powdered, USP grade calcium carbonate than with limestone particles passing through a 1,000-mu screen and retained by a 417-mu screen. Crushing these particles to allow them to pass through a 74-mu screen caused them to behave like the powdered calcium carbonate. Particles of this limestone had to at least pass through a 147-mu screen to cause a greater reduction in gain; the finest particles tested (passed a 74-mu screen) reduced performance most. When graded levels of fine and medium particles were fed, the higher levels reduced gain, and less of the fine particles was required to produce a given reduction. In a high Ca-low P diet, fine particles of the Ca source were more deleterious than medium. Apparently, chicks can shunt excess Ca in the form of medium particles (150 to 1,000 mu) through the digestive system better than they can the more reactive, fine particles.