Jan. 8,19x7 
Ewes' Milk 
33 
Weight increase in the development of an early lamb from birth to the 
time when it is most profitably marketed (approximately three months) 
is marked by two distinct processes of increment: (1) Growth 1 and(2) mast, 
or fattening. It is obvious that the first is the more important process, 
since it determines size and weight. Fattening is merely a padding of 
the structural tissues of the body and does not contribute material for 
growth or structural increase. It is obvious that fattening would be of 
little value in young lambs which failed to make growth. 2 On the other 
hand, young animals may make good growth and yet not present that 
condition of “finish” demanded by the market if deposition of fat has 
not gone hand in hand with growth, a condition not uncommonly found 
in calves fed on skim milk. 
The direct body-increment value of milk fat then lies chiefly in its 
capacity to promote mast simultaneously with growth, so far as the grow¬ 
ing of early lambs for market is concerned. That milk fat is necessary 
and can not be entirely substituted with success in the ration of growing 
animals is conclusively shown by the experiments of Mendel and Os¬ 
borne (11). 3 Their observations are in entire accord with the practical 
knowledge of feeders and breeders that young animals make a more 
rapid continued growth when given whole milk. This is well illustrated 
by the fact that no successful exhibitor would fit calves for the show ring 
with skim milk. Milk fat here is shown to have an indirect effect on 
weight increase by stimulating growth. Since fat in this capacity serves 
as a stimulus and not as a material for structural increase (growth), its 
quantitative variability in milk is probably not so important from this 
standpoint, a conclusion which is also suggested by the practical results 
shown in this paper. In other words, milk which is normally low in fat 
appears still to supply a sufficient amount of this substance to growing 
animals, provided it is available in sufficient quantity to meet the demand 
for protein and ash—that is to say, the demand for proteins and ash is 
relatively so much greater than the demand for fat in growing animals 
of suckling age that milk which is quantitatively sufficient to supply the 
former will contain a large enough total to aqswer all demands for the 
latter. 
RELATION OF MILK YIELD TO GROWTH OF LAMBS 
The effect of the quantitative factor in the milk yield of ewes on suc¬ 
cessful sheep raising under our ordinary farm conditions is a question of 
economic importance, although little or no attention is being paid to it 
1 Repair and maintenance are here included with demands for growth. 
* Just the contrary is true in mature animals that have finished their growth. 
8 "It has been shown that this cessation of growth can be stopped and growth resumed by the substitu¬ 
tion of other naturally occurring fats for part of the lard in the ration. In butter fat, egg fat, cod-liver fat* * 
and beef fat, and more specifically in the fractions of these containing the oil components liquid at ordinary 
temperatures, there exists a determinant of growth in the sense in which this expression has been discussed 
above." (n, p. 216.) 
