14 UNIV. OF N, H. AGR. EXPERIMENT STATION [Bulletin 250 



Blood counts show that the hemoglobin (oxygen carrier of the blood) 

 in blood of paralytic birds is less than normal. Of the different kinds of 

 white corpuscles, the lymphocytes are most numerous, denoting the 

 presence of an infection. The white corpuscles which overcome infec- 

 tion, the polymorphonuclear leucocytes, are fewer in the blood of paralytic 

 birds. That the formation of blood cells in paralytic birds is being seri- 

 ously disturbed is shown by the decreased content of mast and eosinophils 

 cells. 



Groups of birds were fed three rations which differed only in the content 

 and source of cod-liver oil, and analyses of the calcium and phosphorus 

 content of the blood were made. There was practically no difference in 

 the phosphorus content of the samples. The calcium content, however, 

 differed. The birds fed a ration containing a combination of 1 per cent 

 cod-Hver meal and 1 per cent cod-liver oil had the highest calcium content 

 in the blood; the 1 per cent cod-liver meal-fed group contained 10 per 

 cent less, and the 1 per cent oil-fed group contained 25 per cent less. 

 {Purnell Fund.) 



VACCINATING POULTRY TO PREVENT FOWL-POX 



Fowls vaccinated two years previously to prevent fowl-pox were found 

 by C. L. Martin and C. A. Bottorff still to be immune to artificial infection. 



Further field tests in 25 commercial poultry flocks show best results are 

 obtained from skin vaccinations when flocks are vaccinated three to six 

 weeks prior to coming into egg production. Flocks vaccinated after com- 

 ing into production suffered a severe setback. In the more severe cases 

 the reaction lasted three to six weeks, production returning to normal in 

 five to eight weeks. 



Six flocks containing 15,000 birds were vaccinated by the "Johnson 

 stab method." It was found that the percentage of "takes" by this 

 method is equal to that of any other, that birds can be vaccinated about 

 three times as fast as with the follicle method, that only one-third as much 

 vaccine is required as for the follicle method, that fewer head lesions are 

 observed, and that the vaccine is more easily applied. 



A report of laboratory and field tests on "Vaccinating for the Preven- 

 tion of Fowl-Pox," by E. M. Gildow and C. A. Bottorff, is published as 

 Station Circular 30. {Purnell Fund.) 



COD-LIVER MEAL PROVES SUPERIOR TO COD-LIVER OIL 



Cod-liver meal proved superior to cod-liver oil in the rations of both 

 young chicks and mature pullets in its effects on growth, amount of pig- 

 mentation, and fertility and hatchability of the eggs produced, in a series 

 of feeding tests conducted by H. O. Stuart and T. B. Charles. 



At seven weeks of age, a lot of 75 chicks fed 2 per cent of cod-liver 

 meal attained an average weight of 19.11 ounces, almost two ounces more 

 than the average of a lot fed 1 per cent cod-liver oil. The lot fed 2 per 

 cent cod-liver oil weighed on the average 15.82 ounces; 3 per cent cod- 

 liver oil-fed chicks weighed 13.81 ounces, and 4 per cent oil-fed chicks 

 weighed 15 ounces. Poorer growth results were obtained from excessive 

 oil feeding, the development was slower and less uniform, and less pigment 

 was contained in the birds. Paleness of the shanks was very apparent in 

 the oil-fed lots. 



