this study was conducted to investigate direct and maternal effects on some economic traits in north iranian native fowls. traits considered were body weight at 1 day of age (bw1), body weight at 8 weeks of age (bw8), body weight at 12 weeks of age (bw12), egg number (en) during the first 12 weeks of laying period, egg weight at 1st day of laying (ew1), mean egg weight at 28th, 30th and 32nd we...

It has not been possible to propagate a malignant neoplasm of the rabbit with cell-free filtrates, or desiccated tumor tissue or by the use of fluid media kept in contact with tumor tissue. These findings confirm the results of previous experiments carried out with early generations of the tumor. The existence of an agent distinct from the tumor cell which could initiate growth has not been dem...

Five weeks old guinea fowls were inoculated intraocularly with a 20% bursal suspension containing a local Nigerian isolate of infectious burfa! disease virus (IBDV) which had a bursal lesion titre of 10· per 0.5 mI. No clinical signs were observed. Gross lesions were absent and microscopic lesions were not found in the bursa, spleen and kidney on days 3 and 5 post infection (PI). IBDV antigen w...

Minute coccobacilliform bodies have regularly been found in the nasal exudate of fowl infected both by injection and by contact with the coryza of slow onset. These bodies are commonly less than 0.5micro in diameter and are predominantly extracellular. They have consistently failed to grow in artificial media. They are held back by Berkefeld V filters which are impermeable to Hemophilus gallina...