FEEDING DAIRY CATTLE 235 
cows were separated into three groups of the same number of cows 
within each of the dairy breeds represented, Holstein, Jersey, and 
Guernsey, according to their production of butter fat; the data 
for the different groups have been combined and are given in the 
following table: 3? 
Returns from Cows of Different Producing Powers 
Per 100 feed units 
Butter! Cont | Nat | Feed 
Groups pounds feed |Teturns| units Bnipee Malas 
pounds | products 
1. Highest producers (134 cows)....| 5291 | $79.10 | $87.72 | 7161 7.39 $2.33 
2. Medium producers (133 cows)....| 420.6 | 71.08] 63.01] 6574 6.40 2.04 
3. Lowest producers (131 cows)..... 338.9 65.95 | 42.17] 6084 5.57 1.78 
Differences between 1 and 3..../ 190.2 | 18.15] 45.55] 1077 1.82 .55 
In per cent............065 56 20 108 18 32 31 
While the difference in the average production of butter fat by 
groups 1 and 3 amounted to 190.2 pounds, or 56 per cent, calculated 
on the production of group 3, the cost of feed for the two groups 
increased only 20 per cent, and that of total number of feed units 
18 per cent. The differences in net returns (the value of products 
above cost of feed), on the other hand, amounted to 108 per cent, 
and 100 feed units produced 31 to 32 per cent more butter fat or 
value of products in case of group 1 compared with group 3; that 
is, the best cows made the largest production at a relatively much 
lower feed cost; hence the percentage increase in the net returns 
secured was much greater than that in butter fat, viz., 108 per 
cent above that for the lowest lot. The number of feed units con- 
sumed in the rations fed was increased by only 18 per cent, and 
the efficiency of the rations calculated per 100 feed units was 
increased by over 30 per cent. 
The same lesson is taught still more strikingly by the results 
obtained with the best ten and the poorest ten cows in the competi- 
tion (Fig. 45); the feed of the former cost $114.66 per head for 
the year, while the net returns were $124.29, or 52 per cent; the 
feed of the latter cost $61.10, and the net returns were $14.89, or 
only 20 per cent. 
The preceding results were obtained with.excellent dairy cows, 
of families that had been bred persistently for a large milk pro- 
duction for many generations. Cows of this type respond to 
heavier feeding by an increased milk production; other cows of 
different breeding, or bred for beef production, would gain in body 
™ Wisconsin Bulletin 226, p. 22. 
