VARIATION OF INDIVIDUAL PIGS IN ECONOMY OF 



GAIN^ 



By R. C. ASHBY and A. W. Malcomson, Division of Animal Husbandry, Minnesota 

 Agricultural Experiment Station'^ 



When the initial tests with self-feeders were undertaken in 19 14 the 

 question at once arose, "What variations will appear in rations as selected 

 by individual pigs?" To answer it 10 pigs were self -fed individually 

 during the summer of 191 5. A study of their rations has been published.^ 

 But in tabulating the data another factor presented itself — namely, 

 material variations in economy of gain by the different individuals. 

 Two similar tests have been continued in order to gain further information 

 on this point. It is our purpose to report here the results thus far ob- 

 tained. • 



While marked variations have been found with all groups tested, no 

 attempt is made to explain them, because facilities have been entirely 

 inadequate to permit a fundamental study. In one instance the junior 

 author has made thorough type and conformation studies of 15 individ- 

 uals. His data will appear in thesis form. 



To date 67 individuals, representing 14 litters, have been fed indi- 

 vidually. The experiments have been conducted during three summers 

 and are reported as tests A, B, and C. As explained later this report 

 includes the data on 63 pigs. 



TEST A, FEEDING PERIOD 128 DAYS 



As mentioned, the records of the pigs fed in 191 5 are already available. 

 A summary for nine pigs is presented here. No. 1 1 being omitted because 

 of its low final weight. For the nine pigs the average initial weight was 

 47.42 pounds and the average final weight 267.33 pounds. A comparison 

 of the pigs is given in Table I. 



Classified according to the degree of variation from the mean or normal 

 grain requirement for the group : 



1 pig shows a variation from the mean of more than 10 per cent. 



2 pigs show a variation from the mean of between 5 and 10 per cent. 

 6 pigs show a variation from the mean of less than 5 per cent. 



' Published with the approval of the Director as Paper No. 152, Journal Series, Minnesota Agricultural 

 Experiment Station. 



2 The authors express to Prof. H. K. Hayes their appreciation for assistance in arranging and verifying 

 the correlation table, and to Dr. C. W. Gay and Miss Alice McFeely for helpful suggestions. 



' AsHBY, R. C. SELF-BALANCED RATIONS BY INDIVIDUAL PIGS. In Amcr. Soc. Anim. Prod. Proc. 1915/16 

 p. 197-209, illus. 191 7. 



Journal of Agricultural Research, Vol. XJX, No. s 



Washington, D. C. June i, 1920 



ui (225) Key No. Minn.-4o 



