The Value of Crossing Strains of New Hampshires for Broiler Production. 



Five strains of New Hampshires were studied to determine whether 

 cross-strain progency are superior to pure-strain progeny in certain broiler 

 characteristics to ten weeks of age. The following crosses were made: 



Meat type x meat type 

 Meat type x dual purpose 

 Meat type x egg type 

 Dual purpose x dual purpose 

 Dual purpose x egg type 



In each of the five matings, males of one strain were mated concurrently 

 with females of the. same strain and with females of a different strain. This 

 technique made it possible to produce simultaneously pure-strain and cross- 

 strain progeny. The cross-strain progeny were half brothers — half sisters 

 to the pure-strain progeny. A total of 751 chicks were produced from these 

 matings. 



Preliminary results show that fertility averaged 7.5 percent and hatch- 

 ability 4.6 percent higher among the cross strains than among the pure 

 strains. Rate of growth of the cross-strains progeny was superior to that of 

 the pure-strain offspring when the two meat-type strains were mated together, 

 but in no other matings. The failure to obtain a "kick" in growth (with one 

 exception) may be due in part to the rather large differences in adult size of 

 the birds among some of the types of matings. 



Cross-strain progeny consumed their feed more efficiently than pure- 

 strain progeny from the same mating in three out of the five matings. This 

 was true even though two of these three groups cross-strain progeny grew 

 at a slower rate than their pure-strain half siblings. Cross-strain and pure- 

 strain progeny from one of the remaining matings were similar in feed 

 efficiency and in the other mating were less efficient in converting feed to 

 meat. 



Cross-strain offspring showed no consistent superiority over the pure- 

 strain progeny in width of breast. Losses due to mortality during the ten- 

 week growth period were approximately the same in the two kinds of off- 

 spring. 



This project will be continued another year with some different strains, 

 and reciprocal matings will be made. 



W. M. Collins 



Problems Involved in the Vaccination of Infectious Bronchitis. 



During the past vear a survey of the existing vaccination program for 

 the last two years was made. The information was compiled on a yearly basis 

 presenting some factual evidence as to the actual problems and their exist- 

 ence throughout the state. The first year 261 questionnaires and the second 

 year 169 questionnaires were returned. This involved some 780,224 birds 

 the first year and 321,992 the second year. 



In both instances it was found that the greatest number of birds was 

 inoculated from 4 to 8 weeks. It appeared the problems of infectious bronchi- 

 tis inoculation were greater in the. fall and winter months. In regard to the 

 age of the birds the greater success was attained in the birds which were 

 inoculated 8 weeks and over. 



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