ECONOMIC USE OF FORAGES IN LIVESTOCK PRODUCTION 9 
grain. Grain was in the form of corn. Forage consumed while in 
dry lot was brome grass-alfalfa hay. Forage consumed as pasture 
was also a brome grass-alfalfa mixture. In deriving the substitution 
relationships, forage consumed as pasture was converted to its hay 
equivalent. Table 4 shows that a rather wide range of forage-grain 
combinations will produce 100 pounds of choice beef. As in produc- 
tion of milk and pork, less and less grain is saved as more and more 
forage is added to the ration. 
Taste 4.—Forage and grain feed combinations and substitution rates 
in production of 100 pounds of gain on choice yearling feeder 
steers * : 
Average quan- 
tity of forage 
required to 
replace 3 
Feed combinations for producing 100 pounds of |Average quantity 
gain in weight of grain replaced 
per pound of 
forage added 
Forage Grain (pounds) (pounds) oe Hien ao 
Forage as per- 
centage of total 
feed (percent) 
a potions tie 953. 4 29. 6 
#00 : 0. 353 2. 83 H 
GOO ake wee 2 882. 7 40. 5 
\ _ 326 3.07 { 
SOOL sew lerrtes 817.5 49. 5 
\ 298 3. 36 { 
eNO iy ek 757.9 56. 9 
\ 271 3. 69 { 
00: PHA ot F 703. 9 |: 63.0 
\ 249 4. 02 { 
WOO Seta een, 654. 0 68. 2 
\ 211 4,74 { 
GOO. Thee Oe 611. 8 72. 3 
\ 189 5. 29 { 
1B SOO wht ee a Shun: 574. 0 75. 8 
\ 166 6. 02 { 
PVE ee 541. 8 78.7 
\ 133 7.52 { 
POo anew hs 515) 1 81.0 
\ aad 9. 01 { 
DOO ok 493. 8 82. 9 
\ 079 12. 50 { 
e008 i ail DOI 478, 0 84. 5 
\ 056 |- 17. 86 { 
POO sn less 467. 8 85.7 
1. 
RO008 Hwee E 463. 0 O28 poe 86. 6 
1 Based on following regression equation: X,=1111.15—0.4219X,+0.0000686 X,2, 
where X,; refers to pounds of forage and X, to pounds of grain per 100 pounds 
of gain. The average gain in weight per steer was 350 pounds; the gain was less 
for steers on the high-grain rations and more for those on the high-forage rations. 
Feed requirements were converted to per 100 pounds of gain as experimental data 
are customarily expressed in that form. 
FEED-SUBSTITUTION RATES IN LAMB FEEDING 
Forage-grain substitution rates for fattening lambs shown in table 
» are based on an experiment at the Iowa Agricultural Experiment 
Station which involved lambs fed six combinations of chopped alfalfa 
hay and corn (2). The rate at which hay substitutes for grain in 
