80 PRINCIPLES OF FEEDING FARM ANIMALS 



to equal a pound of mixed grain in nutritive effect, while in the case 

 of a poor quality of this hay it will take 3 pounds to equal a feed 

 unit, etc. 



The value of pasture may vary between 6 and 12 units per day, 

 according to the kind and the condition of the pasture and the 

 production of the cows. The former figure may be applied in case 

 of scant or largely dried-up pastures or for dry cows; the latter 

 for heavy-producing cows on luxurious pasture. 



A simple example will readily explain the application of the 

 system. We will suppose that a cow ate 750 pounds of hay, 150 

 pounds of wheat bran, and 90 pounds of ground corn during a cer- 

 tain month. She consequently received : 



7.50 divided by 2.5, or 300 feed units in the hay eaten; 



150 divided by 1.1, or 136 feeds units in the bran, and 



90 feed units in the corn, 

 making a total feed consumption of 526 feed units for the 

 month. If she yielded 30 pounds of butter fat during the month on 

 this feed, she produced 30 -=- 5.26, or 5.7 pounds of butter fat per 

 100 feed units. 



By the use of the unit values given, the feed consumption of in- 

 dividual cows for an entire year may be obtained and compared 

 with their production, thus enabling a farmer to determine whether 

 a cow is a sufficiently high and economical producer to remain in 

 the herd, and the net returns for the feed which each cow in the herd 

 has yielded. It also makes it possible to compare the results obtained 

 in different herds, and furnishes valuable data for studies of the 

 relation of feed to dairy production. 



The Feed-Unit Standard. — The following feeding standard for 

 dairy cows, according to the feed-unit system, has been proposed by 

 Hansson, of the Eoyal Swedish Academy, for a 1000-pound cow 

 per day: 



For maintenance, 0.65 pound digestible protein and 6.6 feed units. 

 For production, 0.045 pound to 0-05 pound digestible protein and y 3 

 feed unit per pound of milk. 1 



Example. — A 1000-pound cow, yielding 24 pounds of 4 per cent milk 

 daily, receives 30 pounds silage, 8 pounds clover hay, 3 pounds corn meal, 

 and 3 pounds gluten feed. How many feed units does she receive in her 

 feed, and how many units are required per 100 pounds of milk and per 

 pound of butter fat? How much digestible protein and how many feed 

 units should she receive according to the feed-unit standard? 



1 " Kontrolforen. Arbetsfalt," Stockholm, 1910. A "Feed Unit" stand- 

 ard for horses has also been suggested by Hansson, based on recent experi- 

 mental work at the Swedish Experiment Station (Bui. 126). 



