520.2123b—Spectinomycin powder.
        
        (a) Specifications.
         Each gram (g) of powder contains spectinomycin dihydrochloride pentahydrate equivalent to 0.5 g spectinomycin.
    
    
    
    
        
        (d) Conditions of use in chickens.
         It is administered in the drinking water of growing chickens as follows:
    
    
        
        (1) Indications for use and amounts—
        
        (i) 
         For increased rate of weight gain and improved feed efficiency in broiler chickens, administer 0.5 g per gallon of water as the only source of drinking water for the first 3 days of life and for 1 day following each vaccination.
    
    
        
        (ii) 
         As an aid in controlling infectious synovitis due to Mycoplasma synoviae in broiler chickens, administer 1 g per gallon of water as the only source of drinking water for the first 3 to 5 days of life.
    
    
        
        (iii) 
         As an aid in the prevention or control of losses due to CRD associated  with M. gallisepticum (PPLO) in growing chickens, administer 2 g per gallon of water as the only source of drinking water for the first 3 days of life and for 1 day following each vaccination.
    
    
        
        (2) Limitations.
         Do not administer to laying chickens. Do not administer within 5 days of slaughter.