ESSAYS 



MEAT PRODUCTION (J. Alan Murray, B.Sc, University College, 

 Reading) 



Butcher's meat consists generally of the dressed carcases of oxen, sheep, and 

 pigs. Two phenomena contribute towards its production — viz. growth and fattening 

 of the animal. In a popular sense these terms are well understood, but they 

 have not been defined, and the phenomena are often confused or imperfectly dis- 

 tinguished. They are, however, distinct ; either may occur apart from the other. 



Growth implies, essentially, extension of the frame and, normally, in con- 

 junction therewith, development of other tissues associated with the same. 

 Fattening implies the formation of new tissue apart from and independently of 

 any extension of the frame. Growth is always positive ; the skeleton develops 

 gradually to its maximum size, and does not again contract at any stage within 

 the lifetime of an animal destined for butcher's meat. Fattening may be either 

 positive or negative ; lean animals become fat, and those which are fat may again 

 become lean. Such changes are referred to, technically, as alterations in the 

 "condition" of the animal. Any alteration in condition or in size alters the mass 

 of the body, but a negative change in the former may be wholly or partially 

 compensated by increase in the latter. The live weight, by itself, therefore, tells 

 nothing. The test of condition is the ratio of mass to size, M/V — i.e. the apparent 

 density of the body. Determination of size by direct linear measurement is a 

 matter of considerable practical difficulty. 



The term "fattening" is employed, technically, to describe what happens when 

 animals consume considerable quantities of readily digestible foods in excess of 

 maintenance requirements. Under these conditions the animals increase in 

 weight and become visibly fatter. But the conditions are also favourable to 

 growth, and if the animal has not already attained its full stature it develops in 

 this direction also. The whole of the increase produced is commonly referred to 

 as "fattening increase," though, as a rule, in modern farming practice, much of it 

 is due to growth. 



In experiments intended to establish relations between food consumed and 

 increase produced, failure to discriminate between growth and fattening reduces the 

 scientific and economic value of the results almost to vanishing point. The two 

 kinds of increase differ in composition and in the rate at which they are formed. 

 Apart from these considerations the total quantity has but little significance. 



Lawes and Gilbert slaughtered certain lean and fat animals and estimated the 

 composition of the entire bodies by chemical analysis. From these data and the 

 recorded weights of various groups of animals in lean and fat condition they 

 calculated the composition of the increase as a whole. The results varied, of 

 course, according to the amount of increase made by the several groups. As a 

 rule only the averages are quoted in textbooks, and this seems to have given rise 

 to a widespread impression that the composition of the increase is constant. 

 That it is approximately constant under like conditions is more than probable; 

 but conditions alter and farming practice varies. A rather drastic change has 

 recently been recommended. 1 Other inferences may be drawn from the analytical 



1 Journal of Board of Agriculture, vol. xxiii. No. 10, p. 986. 



665 



