ANIMAL PRODUCTION. 69 



ANIMAL PRODUCTION. 



The role of inorganic phosphorus in the nutrition of animals, E. B. Hart, 

 E. V. McCoLLUM. and J. G. Fuller (Aiiicr. Jour. I'liysiol., ;i:i (WO!)), No. //, 

 PI). 2.'i6-277). — The object of these experinieuts was to determine whether in- 

 organic i)hosphates could take the place of organic phosphates in a ration for 

 growing swine. 



In the first experiment IG pigs, averaging 47 lbs. each in weight, were fed for 

 95 days a basal ration low in phosphorus, which consisted of rice, wheat 

 gluten, and of wheat bran fi-om which phytin, the organic form of phosphorus, 

 had been removed by washing. The pigs which were fed the basal ration each 

 received daily 1.12 gm. of phosphorus and made an average gain of 28.i}3 lbs., 

 but though they gained in weight their limbs were weak and their appetites 

 poor. Two lots of pigs that had jirecipitated calcium phosphate supplying daily 

 5..5 gnis. and 2.7") gms. phosphorus, respectively, added to their basal ration 

 gained in the same time an average of 52.6 lbs. per pig. The lot fed a normal 

 ration of ground rice, whole bran, and wheat gluten that contained on an aver- 

 age 5.4 gms. of phosphorus in the daily ration gained an average of 59 lbs. in 

 weight per pig. The final lot fed a normal ration of ground corn, ground oats, 

 wheat middlings, and oil meal supplying daily 5.45 gms. phosphorus made an 

 average gain of 65.5 lbs. per pig. 



These experiments were repeated, but in addition two known tri-calcium phos- 

 phates were used. One was a bone ash, the other a crude ground phosphate 

 rock (floats). During a portion of the experimental period one animal from 

 each lot was placed in a cage and an accurate balance of the income and outgo 

 of phosphorus was determined. The intake of phosphorus of the pig that re- 

 ceived only the basal ration was l.OS gm. daily, but the average amount retained 

 was but 0.53 gm. daily, which was insufficient for complete nutrition. The 

 average intake of total phosphorus in the lots receiving inorganic phosphates as 

 a supplementary food was from 4 to 5 gm. daily. "The average amounts re- 

 tained daily ranged from 1.5 gm. in the bone-ash fed pig to 2.35 gm. in the 

 float-fed pig. There wei-e days when the float-fed pig retained 3.11 gm." 



Analyses were made of the feeds and of different parts of the slaughtered 

 animals. The specific gravity and the breaking strength of bones were also 

 determined. From data secured from the two experiments reported the follow- 

 ing deductions are drawn : 



"On the ration extremely low in phosphorus, pigs made as large gains up to 

 75 or 100 lbs. when starting at weights of from 40 to 50 lbs. as animals receiv- 

 ing an abundance of this element. After reaching this point loss of weight 

 began, followed by collapse. 



" When such low phosphorus rations as induced the above symptoms were 

 supplemented with calcium phosphates, no untoward results appeared. Animals 

 fed a low phosphorus ration, supplemented with inorganic phosphates, made as 

 vigorous a development as others receiving their phosphorus supply wholly in 

 organic form. 



" Precipitated calcium phosphates, a mixture of di- and tri-calcium phos- 

 phates, gave no better results than did floats, a crude tri-calcium phosphate. 



" Phytin as the supply of phosphorus gave no better results than the inor- 

 ganic phosphates. 



"A young animal of 40 lbs. weight receiving inorganic phosphates, together 

 with other salts as supplementary to a ration very low in mineral constituents, 

 grew to be an animal of 280 lbs. weight, bore a litter of fairly vigorous pigs, 

 which on the same ration completed the cycle back to 80 lbs., while animals on 

 the same ration less the inorganic phosphates collapsed in three months, with 

 loss of weight accompanied by a loss of the use of their limbs. 



