14 2 Journal of Agricultural Research voi.xx. No. 2 



THE PROBLEM 



Profitable production of broilers begins with the baby chicks and 

 extends over a period of about eight weeks, at the end of which time 

 the birds should weigh, as a flock, approximately 1% pounds each. 



Our problem consisted of two parts: 



1. To ascertain the mineral content of poultry feeds and, from this as 

 a basis, to determine the potential acidity and potential alkalinity of 

 these feeds. 



2. To determine the acid-base balance of the feed mixtures used in 

 our experimental feeding work in the production of broilers, giving some 

 of the feeding results. 



EXPERIMENTAL METHODS 



The baby chicks were produced from a single flock of pure-bred 

 Single-Comb White Leghorns, bred at the station and college poultry 

 plant, and were hatched in the same incubator. Each lot was housed 

 under similar oil-burning hovers of 100-chick capacity. 



The experiment was carried on in periods of 8 weeks each and extended 

 over three periods, or 24 weeks. The samples of feeds for analyses were 

 obtained, as composite samples, from the various bags of feed used in 

 the experiment. The potential acidity and potential alkalinity were 

 estimated from the mineral analyses of the feed samples. 



The caloric values of all the animal food rations — No. 2, 3, 4, and 7 — 

 are about the same, being 27 to 31 per cent protein calories. The soybean 

 meal ration is in the same column so far as protein calories are concerned. 

 The grain feeds have less protein caloric value, having only 12 per cent. 

 Dried buttermilk functions as base. The meat scrap and bone meal and the 

 digester tankage are base on account of the large amount of calcium in the 

 bone. Blood is normally alkaline because of the sodium salts. The grain 

 ration is 61.96 cc. acid per pound. The mashes are all alkaline or base. 

 Those containing milk or bone — rations 2,3, and 4 — run high in base ele- 

 ments, while the blood meal runs only 41.21 cc. base and compares 

 favorably with the two rations containing no animal food but contain- 

 ing protein from leguminous sources. 



It will be noted that ration No. 6, the peanut-meal mixture, is low in 

 protein caloric value. This is due to the fact that the peanut meal 

 used was ground peanuts and hulls, not fat-extracted, and showed 40.4 

 per cent fat content. 



Many interesting things are brought out by Table IV. The greatest 

 gain in weight in chicks is during the first eight weeks, or the first period. 

 Following the first period the increase in weight is gradually less during 

 the remainder of the two periods. 



The amount of feed required to produce a pound of gain gradually 

 grows greater as the bird becomes older. 



