During the past two years experimental high efficiency feeds have heen 

 compounded and studied. Two of the feeds were tested in each of the two 

 years of work. The best high-efficiency feed improved feed efficiency 20 

 percent in one year and 7 percent in the second year. Of the total of five 

 high-efficiency feeds used, one was equal to the control in one year and 

 all others gave a better feed efficiency. The average improvement was 12.1 

 percent. 



R. C. RiN'GROSE, L. AI. Potter, R. 'SI. Hatch 



Immunization of Two-Day-Old Chicks Against Infectious 

 Bronchitis and Newcastle Disease by the Spray Technique 



While the use of a field strain of infectious bronchitis virus, in a vac- 

 cine in birds over four weeks old, has shown definite advantages in the 

 control of the disease in replacement flocks, the procedure could not be 

 used with reliability in broiler flocks. Further, at times serious compli- 

 cations with other respiratory and protozoan diseases often occur when 

 birds over four weeks old are inoculated with infectious bronchitis virus. 



During the past year a concentrated eft'ort has l)een made in the 

 screening of field strains. One strain has been found which has apparent 

 safety and immunizing properties when used on parental-immune chicks at 

 two days of age by means of a spray technique. In addition, it has been 

 found possible to combine this strain with the Blacksburg strain of New- 

 castle virus and to immunize the birds against both Newcastle disease and 

 infectious bronchitis. 



T.aboratory chicks were inoculated at two days of age with the com- 

 l)ination vaccine. The chicks were parentally immune to Newcastle and 

 infectious bronchitis. At 12 weeks oi age the same birds, according to 

 challenge and serological test, possessed resistance to Newcastle disease 

 and infectious bronchitis. 



During the past 7 weeks field trials have been initiated on some 

 176,000 birds under various conditions with apparent safety- Resistance 

 to both Newcastle disease and infectious bronchitis has been demonstrated 

 at five weeks from such trials. 



Therefore, if upon further trials at older ages resistance to Newcastle 

 disease and infectious bronchitis can still be demonstrated, it would appear 

 we may have a procedure of immunization which would Ije of considerable 

 help to the industry in controlling Newcastle disease and infectious l)ron- 

 chitis. 



W. R. DuxLOP 



Influence of Egg Holding-Room Environment upon the 

 Hatchability of Eggs and the Quality of Chicks Hatched 



In order to determine whether the environment of the holding room 

 efl^ects hatchability and chick quality an experiment was conducted in which 

 hatching eggs were held under three conditions : ( 1 ) walk-in refrigerator 

 (temperature 50°. humidity 80 percent), (2) egg cellar (average condi- 

 tions). (3) office (high temperature and low humidity). 



Hatchabilitv data were ol)tained and the chicks were graded bv a 

 competent grader. The results are as follows : 



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