10 CIRCULAR 905, U. S. DEPARTMENT OF AGRICULTURE 
lamb feeding falls somewhere between that for hogs and dairy cattle | 
or beef fattening. Twenty-five pounds of choice or prime gain on | 
feeder lambs can be produced with 40 pounds of hay and 130.9 pounds 
of grain. A 10-pound increase in forage reduces the grain require- 
ment for producing 25 pounds of gain to only 125.1 pounds; thus an 
average of 0.58 pound of grain is saved per pound of hay added at this | 
level. At the other extreme, an increase from 160 to 170 pounds of 
forage per lamb results in a decrease from 92.5 to 91.6 pounds of 
grain required to put on 25 pounds of prime or choice gain—a re- 
placement rate of only 0.09 pound of grain saved per pound of forage 
added. 
Tasie 5.—Forage and grain feed combinations and substitution rates 
in producing 25 pounds of gain on feeder lambs} 
Average quan- 
Feed combinations for producing 25 pounds of |Average quantity tity of forage 
~ Babnued ee eee required to | centage of total 
| forage added Dada x feed (percent) 
Forage Grain (pounds) (pounds) grain (pounds) 
Pounds 
AQ eh es ae 130. 9 23. 4 
0. 58 1.72 
ee ee 125. 1 28. 6 
\ 50 2. 00 { 
GOLA oe eee 120. 1 33.3 
\ ae 2. 27 { 
Occ ae ON: 115.7 37.7 
\ 39 2. 56 { 
Rimi Ma ea ee 111.8 41, 7 
\ 35 2. 86 { 
605. ee 108. 3 454 
\ 32 3.12 { 
OG Sete a eto 105. 1 48, 8 
\ 28 3.57 { 
HO. se 102. 3 51. 8 
\ 26 3. 85 { 
ied ees aes 99. 7 ha 6 
\ 23 4. 35 { 
130s kee a 97. 4 57. 2 
\ 20 5. 00 { 
IC ieee Ups oes 95. 4 59.5 
\ 16 6. 25 | 
15g thee Polos ig 93. 8 61.5 
\ 13 7 69 { 
16Q ule - 92.5 63. 4 
| - 1 ea al 
ezaiein ar ee 91.6 || Oe 64.7 
1 Based on following regression equation: 
X,=2.3118—0.0037X,—¥y (2.3118—0.0037X;)2++ 0.021175. X,— 0.000031 Xy?— 5.4267 
0.014792 
where X, refers to pounds of forage and X;, refers to pounds of grain per 25 pounds 
of gain. 
Cost RELATIONSHIPS 
For a farmer who buys both grain and forage in the market, feed 
subsitution rates and market prices of the feeds determine the least- 
cost feed combination for any particular level of production per 
