228 POULTRY BREEDING AND MANAGEMENT 



more food during the cold weather than during the warm. 

 This is because it requires more food to keep up the heat of 

 the body, and for heat-producing purposes cheap fat foods 

 serve the purpose as well as expensive protein foods. 



Nutritive Ratio. The hardest problem, therefore, in 

 poultry feeding is to compound suitable rations containing 

 the necessary protein in its most available form and at 

 reasonable cost for heavy production. The nutritive ratio 

 is the ratio of digestible protein to digestible fat and heat- 

 producing foods. For egg production a narrow nutritive 

 ratio should be fed. A ratio of one of protein to four or five 

 of carbohydrates and fat is a narrow ratio and will give good 

 results in egg production. In figuring the ratio the fat is 

 multiplied by 2^ as it is estimated that one pound of fat 

 is equal to 2% pounds of carbohydrates. 



It should be understood, however, that the nutritive ratio 

 in itself does not necessarily indicate the true value of the 

 ration. Palatability and other factors have to be consider- 

 ed. At the Utah Station two rations having the same nutri- 

 tive ratio were fed to two different pens of fowls for a year. 

 One of them gave a yield of 201 eggs per fowl; the other 

 133. There was a difference in the kind of the food, but not in 

 the nutritive ratio. Two other pens having rations of simi- 

 lar nutritive ratio gave yields of 101 and 143 eggs respec- 

 tively. At the West Virginia Station laying hens fed a 

 narrow ratio, or nitrogenous ration, produced 17,459 eggs, 

 while the pens with a wide, or carbonaceous ration, laid 

 9,708 eggs. During the experiment the former fowls gained 

 in live weight 1 pound 4 ounces each, while the latter gain- 

 ed only about one-tenth of a pound each, Other experi- 

 ments have shown the superiority of the narrow ratio, or 

 the ration rich in protein or nitrogen. 



The proper nutritive ratio, however, does not guarantee 

 a good egg yield. Regard must be had to the kind of foods 



