UNIVERSITY OF ILLINOIS
Agricultural Experiment Station
BULLETIN No. 314
A TECHNICAL STUDY
OF THE MAINTENANCE AND
FATTENING OF LAMBS
AND THEIR UTILIZATION OF A RATION
OF ALFALFA HAY AND CORN
BY H. H. MITCHELL, W. G. KAMMLADE,
AND T. S. HAMILTON
URBAXA, ILLINOIS, AUGUST, 1928
CONTENTS
PACE
PLAN OF THE EXPERIMENT 31
CHEMICAL COMPOSITION OF CHECK LAMBS 33
MAINTENANCE EXPERIMENT 37
Body Weight Changes 38
Results of Digestion and Metabolism Trials 38
Average Daily Intake of Feed and Energy 40
Composition of the Maintenance Lambs 40
Changes in Energy Content of the Maintenance Lambs 44
Corrected Maintenance Requirements 45
Net Energy Required for Maintenance 47
THE FATTENING EXPERIMENT 48
Results of the Digestion and Metabolism Trials 50
Composition of the Fat Lambs 51
Composition of the Gains in Weight 54
Distribution of Added Nutrients in the Carcasses 56
Utilization of Feed Energy in Fattening 57
SUMMARY 59
A TECHNICAL STUDY OF THE MAINTENANCE
AND FATTENING OF LAMBS AND THEIR
UTILIZATION OF A RATION OF
ALFALFA HAY AND CORN
H. H. MITCHELL, W. G. KAMMLADE, AND T. S. HAMILTON1
The lack of information concerning the nutrient requirements of
sheep and their efficiency in utilizing food nutrients, is mainly responsi-
ble for the general application to sheep of results obtained with cattle,
and for the complacency felt in thus transferring bodily to one species
information and measurements secured with another. It is high time
that experimental investigations on the nutrition of sheep be carried
out that will either establish this assumed similarity between sheep
and cattle or will permit a separate evaluation of sheep.
In Bulletin 283 of this Station is a description of an experiment
on 12 sheep designed to determine the maintenance requirement in
terms of metabolizable energy, the composition of gains put on during
fattening, and the relation between the metabolizable energy consumed
above maintenance and the gross energy of the gains made. The ra-
tions used in all cases consisted of alfalfa hay only. The rate of fat-
tening secured on alfalfa hay alone was slow, and the refusal of feed
in some of the metabolism trials as well as during the fattening period
complicated the interpretation of some of the results secured. It was
therefore decided to repeat the experiment using a ration more accept-
able to sheep and more conducive to fattening. In other respects also
the plan of the second experiment differed from that of the first tho
the objects sought were essentially the same.
PLAN OF THE EXPERIMENT
The general plan of the experiment provided for the slaughter and
analysis of a group of check lambs at the beginning of the experiment
and of a group of fattened lambs at the end of the experiment. From
these results the composition of the gains put on during fattening could
be computed. A third group of lambs was to be fed such amounts of
the fattening ration as may be required for the maintenance of weight,
The slaughter and analysis of these lambs at the end of their mainten-
ance feeding either would demonstrate that the ration consumed was
in fact a maintenance ration (with respect to energy) or would afford
'H. H. Mitchell, Chief in Animal Nutrition; W. G. Kammlade, Assistant Chief in Sheep
Husbandry ; and T. S. Hamilton, Associate in Animal Nutrition.
31
32 BULLETIN No. 314 [August,
a more or less satisfactory' basis for correcting the ration fed by mak-
ing due allowance for energy stored in or lost from the body during
the feeding period.
It was decided to use young lambs in this work and to carry the
fattened lambs to a desirable market weight of approximately 90
pounds. In the spring of 1925 the required number of grade lambs,
about three months of age was available, and accordingly on April 16
six of these lambs were killed and subsequently analyzed. These were
to constitute the check group. The ration chosen consisted of equal
parts of alfalfa hay and corn. Two other groups of lambs were started
on maintenance and fattening rations, but they did not eat well. They
did not adapt themselves to the system of individual feeding, probably
because they were too young, and the experiment was therefore dis-
continued.
In the fall of the same year some lambs were obtained from an
Oregon ranch. They were a mixed group of ewes and wethers, dropped
by western ewes bred to purebred Hampshire rams. At the time the
experiment was resumed in September, they were from five to five and
a half months old. On September 21, eight of these lambs were slaugh-
tered and analyzed as a check group; another group of eight was fed
a ration of alfalfa hay and corn in equal parts for maintenance of
weight, while a third group of nine was fed for fattening on the same
ration. The lambs were fed individually in all cases.
The individual feeding of these lambs was successful. The main-
tenance group was on feed until the early part of February or March,
the final date varying for different individuals. During this period
metabolism and digestion trials were made upon each of the eight
lambs. At the termination of the period of experimental feeding, the
lambs were slaughtered and analyzed.
The lambs in the fattening group were fed until weights approxi-
mating 90 pounds were reached, when they were slaughtered and ana-
lyzed. Two of the lambs were slaughtered on December 21, 1925, five
on January 5, 1926, one on February 9, and one on February 18. Di-
gestion and metabolism trials were made upon only five of the nine
lambs in this group.
The pen in which the lambs were allowed to exercise was approxi-
mately one by five rods. The lambs were fed in individual feeding
crates located in a shed open toward the south. Water and salt were
provided ad libitum. Except at feeding time, the lambs were allowed
the run of the open pen. Body weights were taken weekly, and all
feed used was sampled continuously and submitted to a routine chem-
ical analysis, including the determination of calcium and of the heat
of combustion. The carcass samples also were analyzed for calcium
and gross energy.
THE MAINTENANCE AND FATTENING OF LAMBS 33
CHEMICAL COMPOSITION OF CHECK LAMBS
Altho the results of the analysis of the first group of check lambs
were not used in the later computations of the experiment, they are
nevertheless reported because of their interest and importance as rep-
resentative of the composition of lambs three to four months of age.
Two samples were prepared from each lamb for chemical analysis:
ll) a carcass sample prepared from one-half of the dressed carcass,
including one kidney; and (2) an offal sample, including the blood,
head, skin, and feet, visceral fats, and all viscera except the kidneys.
A composite wool sample for the group of six lambs was also analyzed,
the lambs being shorn before slaughter. In preparing the two samples
the different tissues were ground separately according to convenience
and ultimately mixed together thoroly.
The slaughter data, the total weights of lean, fat, bone, offal, and
wool, and the percentage composition of the chemical samples from
the first group of grade lambs will be found in Tables 1, 2, and 3. The
estimated percentage composition and gross energy content of the
lambs, on the basis of the live weight as well as of the empty weight,
are given in Table 4.
About a year before the first group of check lambs was slaugh-
tered, advantage was taken of an opportunity to analyze a number of
new-born lambs that had died from unknown causes a day or two
after birth. Four of these new-born lambs were of average weight or
better and appeared normal in every respect. The first two were pre-
mature, having been dropped about ten days before the termination of
the normal gestation period. They were subnormal in weight and
composition. Since these analyses have not heretofore been published,
they have been summarized in Table 5. They possess the same gen-
eral significance as the analysis of other groups of lambs reported in
this bulletin.
The second group of check lambs, used in the computations of
this experiment, was slaughtered and analyzed according to the same
scheme as the first group, the samples being composited in exactly
the same manner. The results obtained are summarized in Tables 6.
7, 8. and 9.
These western lambs were in somewhat poorer condition than the
younger grade lambs killed in the spring of 1925. Another noticeable
difference between the western and the grade lambs relates to the ash
content. The western lambs contained 4.79 percent of ash on the basis
of the empty weight, while the grades contained only 3.32 percent. The
calcium made up approximately the same percentage of the total ash
in each group, i.e., 28.5 and 27.4. The greater ash content of the west-
ern lambs may be traced definitely to their greater bone content. No
weights on the total skeleton are available, but the bones in the dressed
34
BULLETIN No. 314
[August,
TABLE 1. — SLAUGHTER DATA FROM FIRST GROUP OF CHECK LAMBS
(All weights in pounds)
Lamb No
1
21
25
12
22
30
Average
Live weight
47.4
50.1
47.8
54.4
50.9
49.7
50.1
Wool
1.76
1.65
1.08
1.71
1.54
1.11
1.48
Blood ...
1.94
2.19
2.25
2.19
2.31
2.38
2.21
Skin and feet
4.44
4.56
4.56
4.38
5.13
4.69
4.63
Caul fat
.56
.56
.50
.56
.19
.44
47
Gut fat
.31
.31
.44
.56
.75
.44
.47
Contents of first three
6.25
4.63
6.38
6.06
4.31
4.69
5.39
Contents of 4th stomach
2.44
2.06
2.13
1.38
1.75
1.31
1.85
Contents of entire
8.69
6 69
8 51
7.44
6.06
6.00
7.23
Warm dressed carcass. . .
Cold dressed carcass
20.81
20.05
3.65
25.38
24.85
2 09
21.06
20.90
76
27.31
26.53
2 86
24.50
23.50
4.08
24.25
23.50
3.09
23.89
23.22
2.76
18.3
13.3
17.8
13.6
11.9
12.1
14.5
Dressing percentage
42.7
49.6
43.8
48.8
46.2
47.2
46.4
TABLE 2. — WEIGHTS OF SAMPLES ANALYZED FROM FIRST GROUP OF CHECK LAMBS
Lamb
No.
Empty
weight
Dressed carcass composite
Offal
Wool
Lean
Fat
Bone
Total
1
kgs.
17.58
19.69
17.81
21.30
20.35
19.84
19.43
grams
5 988
7 352
6 035
7 672
6 876
6 748
6 779
grams
1 391
2 035
1 432
2 286
1 706
2 Oil
1 810
grams
1 736
1 722
1 783
1 998
2 028
1 808
1 846
grams
9 115
11 109
9 250
11 956
10 610
10 567
10 435
grams
6 740
6 730
7 140
7 161
7 561
7 224
7 093
grams
798
748
490
776
699
503
669
21
25
12
22
30
Average.. .
TABLE 3. — PERCENTAGE COMPOSITION AND ENERGY VALUE OF SAMPLES
ANALYZED FROM FIRST GROUP OF CHECK LAMBS
Lamb
No.
Dry
substance
Crude
protein
Ether
extract
Ash
Calcium
Calcium
in percent
of total
ash
Gross
energy
per grams
Carcass composite samples
1
44.04
17.11
21.23
5.21
1.85
35.5
sm. cals.
2 866
21
48.32
16.32
24 77
4 62
1 46
31.6
3 088
25
43.47
18.26
19 62
5 22
1.72
33.0
2 746
12
53.56
15 95
26 74
3 55
99
27.9
3 306
22
44.02
16.87
22 15
3 90
1.28
32.8
2 897
30
44 74
16 46
23 32
3 55
1 01
28 5
2 951
Average. . . .
46.36
16.83
22.97
4.34
1.39
31.6
2 976
Offal samples
1...
32 . 08
16 89
12 10
2 47
59
23 9
1 969
21
34.31
16.88
12 79
1 85
47
25 4
2 086
25
29.76
17 07
9 93
2 10
48
22 9
1 780
12
32.70
16 06
12 22
1 83
40
21 9
2 112
22 .
28.93
16 37
0 52
1 89
39
20 6
1 760
30
28.94
16 44
9 58
1 94
41
21.1
1 743
Average
31.12
16.62
11.02
2.01
.46
23.5
1 908
Composite wool samples
1-30... 91.89
70.75
13.75
7 47
.28
3.75
4 938
1928]
THE MAINTENANCE AND FATTENING OF LAMBS
35
TABLE 4. — PERCENTAGE COMPOSITION AND GROSS ENERGY CONTENT
OF FIRST GROUP OF CHECK LAMBS
Lamb
No.
Dry
substance
Crude
protein
Crude
fat
Ash
Calcium
Calcium
in percent
of total
ash
Gross
energy
per gram
On basis of live weight
1
32 11
15 15
13 29
3 25
98
sm. cals.
2 013
21
36 80
15 32
16 37
3 08
86
2 290
25
30.46
15.00
11.95
3.09
. 90
1 870
12
38 33
14 63
16 94
2 47
80
2 370
22
32 47
15 24
13 72
2 64
72
2 059
30
32.27
14.. 54
14.32
2 44
.61
2 050
Average. . . .
33.74
14.98
14.43
2.83
.78
2 109
On basis of empty weight
1. ..
39 30
IS 54
16 27
3 98
1 20
30 2
2 465
21
42.46
17.67
18.82
3.56
1.00
28 1
2 643
25
37 06
IS 25
14 54
3 76
1 09
29 0
2 276
12
44.41
16 95
19 63
2 SB
70
24.5
2 746
22
36.86
17.30
15 58
3.00
,82
27.3
2 338
30
36 69
16 53
16 28
2 77
70
25 3
2 331
Average. . . .
39.46
17.54
16.85
3.32
.92
27.4
2 467
TABLE 5. — PERCENTAGE COMPOSITION AND GROSS ENERGY OF XEW-BORN LAMBS
Breeding
Birth
weight l
Dry
substance
Crude
protein
Ether
extract
Ash
Gross
energy per
grams
Ibs.
6 0
18 99
11 38
2 32
2 35
sm. cals.
1 Oil
7 0
18 04
11 19
1 SI
•' (is
882
9 75
23 02
14 94
2 S2
3 36
1 148
10 7
23 32
15 44
2 SS
3 02
1 30S
Southdown
6 6
24 69
15 19
2 76
3 S4
1 324
Southdown
7.2
22 66
16 44
2 44
3.35
1 236
Average2
23.42
15.50
2.72
3.39
1 254
'Sixteen Southdown lambs dropped from ewes in the University flock during the same year
averaged 7.7 pounds in weight at birth; 24 Rambouillet lambs averaged 9.7 pounds. Exclusive of
first two lambs.
TABLE 6. — SLAUGHTER DATA FROM SECOND GROUP OF CHECK LAMBS
(All weights in pounds)
Lamb Xo
156
29
64
44
83
7>
80
81
Aver-
age
Live weight
59 7
60 6
5s 4
60 6
57 4
5S 1
•
58 6
Wool
3 38
3 38
2 81
3 06
3 69
•' ti3
3 13
3 13
3 15
Blood
3 44
2 81
2 63
2 25
2 7.")
3 00
2 r:>
2 63
2 7s
Skin and feet
6 38
4 75
5 38
4 SI
5 (ID
-
5 19
5.38
5.34
Caul fat .
25
69
3s
81
44
."id
56
38
.50
Gut fat
56
44
56
50
44
44
44
44
.48
Contents of first tin
5 19
6 81
4 81
5 31
9 81
6 56
6 06
5.69
6.28
Contents of 4th stomach
4 31
3 13
3 06
2 50
3 56
2 88
2 69
2 44
3.07
Contents of entire
alimentary tract
Warm dressed carcass. .
Cold dressed carcass ....
Percent shrinkage
Percent "fill"
9.50
26.19
25.61
2.21
15 9
9.94
28.19
27.60
2.09
16 4
7.87
27.94
27.20
2.65
13 7
7.81
27.56
26.86
2.64
13 3
13.37
26.25
25.49
2.90
22 1
9.44
26.38
25.68
2 ..65
16 4
8.75
27 . :>!>
26.66
3.27
15 1
8.13
8
!
3.28
14.6
9.35
26.99
26.27
2.70
15.9
Dressing percentage. . . .
42.9
45.6
47.3
46.0
42.1
44.8
45.9
44.9
36
BULLETIN Xo. 314
I
ss .i;ed 1.846 grams for the grades and 2.588 grams for the
western lambs, which is equal to 9.52 and 11.61 percent respectively
the empty weight and 11.45 and 13.52 percent of the fat-free empty
weight.
TABLE 7. — WEIGHTS OF SAMPLES ANALYZED FROM SECOND GROUP OF CHECK LAMBS
Lamb
;•.
Empty
Dressed - •- - •
-'•
Wool
:.'.
Fat
Bone1
!' •'
ii
1
22 --
22. 97
22 :
22 7
21.41
21.75
22.4
21. (
22.30
-
' 413
1 •-;
. . ,-
] L7
- B •-
• '
r 896
: _ K
' 616
-
: 92
1 441
'
".
1 133
1 130
1 211
1 000
1 349
•
- 858
2 • •
.
2 641
2 523
2 <
2 646
2 543
. 588
11 453
12 047
9
' 78 I
11 3.50
• 2 •
11 7i
10 342
11 553
-
- 852
-
7 571
" 617
7 ;-
7 • 7
-
7 886
- . '
1 .533
1 533
1 27i
; 388
1 674
1 193
1 420
1 • -•
1 430
• .
44
S3 ... .
--
-
51
' : - ...-
Exclus f I ies of 1 I and feel
TABLE S. — PERCENTAGE C< - fa < ION AND ENERGY VALUE OF SAMPLES
ANALYZED FROM SECOND GROUP OF CHECK LAMBS
Lamb
,
-
pro-
: • -
-
Calcium
in percent
• .
C
per trr
•mposite san.:
156.. ..
•
'
- • -
Z
-
-
-
ti
..
•
17
17 1
7
17.31
- - -
•
•
- ~
;
_ - -
-
- -
•
• -
7 -
7 1
-
- ;
'
1 !
4.77
-
•-
5.90
5.90
.- ' 1
-
•
_
1.56
_
•
•_
1.99
1 ~
1 2
34.4
- J
•
-
•
3.3 . 7
caii.
2 -
' -
_
^
- 177
^
2 691
\
-
•
•
Offal samples
156
27 7
i
i
30.26
-
-
•
-
16.44
7.32
12.63
13.15
9.60
11.14
9.91
10.36
i ii
•
ii .
.71
_
88
77
-
.71
K
23.1
. !
2
24.6
-
25.0
24.5
J7
2 005
1 701
2
-
1 77-
1 914
1 71-
•
.
-
-
78
-
-
Composite wool sample
Entire group
91.57
70.19
6.47
10.88
.28
2.57
4 563
: -
THE MAINTENANCE AND FATTE>
-
TABLE 9. — PERCENTAGE COMPOSITION AND Gr;< .•-- I : NTENT
OF SECOND GROCP OF CHECK LAMBS
Lamb Dry Crude :
Xo. substance pr- . • :ract
Ui
-
-
•
ri
Gross
'-
• sram
1 . M • . reigfat
156 . 31 66
16.66
16.42 12 12
• - 13.04
LS.84 14.75
16 . 02 10.95
11.37
17.06 11.41
16.96
16.40 11.90
4.73
32
3.45
4.34
3.49
; 21
;
3.99
- 2
1.32
1
. _
_
2
-
.01
1.14
', ','.', .' ','•',
/ i - o; *. to
co2s.
i • \
. 17
- - •
I 851
1 909
1
: a •-
1 171
29 ... 34 73
64 33.74
44 35 OS
83 . 30 9>,
78 ... . 32 54
80 ?.3 33
81 . •••-•,
Average 33.09
• _ . | • - • - gfai
156 37.64
19.81 11.51
19.64
L8.7S 15.10
18 . 29 L7 . 02
14.11
19.17 13.61
20.09 13.44
1 -• _ •
19.52 14.15
! • -
1 S7
1
'
1 18
'
- 9S
1 - -
4.79
: ^
-
1.45
>7
1.43
3
18
1.36
2 1 1
2 V '
_ '
2 581
. -'
_ 284
2 274
2 2li
2 346
29 41.54
64 39 09
44. 10.49
83 "
78.. 5.8J
39 24
81 S.24
Average 39.37
MAINTENANCE EXPERIMENT
The feeding of the eight maintenance lambs started on October
10. 1925. Their weekly weight.- from this ".mil February 6 or 13
are given in Table 10.
TABLE 10. — WEEKLY WEIGHTS OF LAMBS DURING MAINTENANCE FEEDING PERIOD*
- ' : ~
Lamb Xo
10
11
-
.
-
136
_
Oct. 10
65
63
65
•
-
63
i
17
.
-
'
i
61
61
24
]
j
66
65
-
31
64
65
65
fifi
65
_
Nov. 7
72
69
'
69
1
-
J
14
-
69
66
64
-
21
69
~
71
~
69
28
67
-
70
69
66
64
Dec. 5
-
66
J
71
1
i
69
12
1
J
'
-
-
19
66
65
•
a
66
66
-
-
69
-
-_
71
•
n
-
Jan -
'
70
73
i
74
70
73
9
70
-
n
-
j |
69
16
69
71
--
j
-I
-
-
23
71
74
-
74
73
-
30
71
73
J
'
73
-
Feb. 6
73
79
77
::
n
1
- .
13
76
-'
Final weight ....
69.4
73.2
71.7
71.6
74.9
69.0
n i
'- -
Average weight .
68.2
69.2
70.6
J
69.3
67.1
70.6
66.5
'Xo. 136 was slaughtered on Fei>: . • -. » N : - : . . . " - » and
Xos. 11 and 43 on March 4. Some of the weekly w, j ;1 from
the table and from the averages because of irregularities incide:.'
38 BULLETIN Xo. 314 [August,
Body Weight Changes
The weight records in Table 10 indicate that the feeding was ap-
preciably more liberal than a maintenance ration. All lambs increased
in weight slowly. They were started on .8 pound of alfalfa hay and
.8 pound of corn per head daily. On November 21 this allowance was
decreased to .7 pound of each feed daily for all of the lambs except
Nos. 75 and 136. The same reduction was made for Lamb 75 on No-
vember 28; Lamb 136 was carried thruout at the higher level. The
chemical composition of the different samples of feeds collected at the
sheep barn and at the Nutrition Laboratory, where the metabolism
tests were run, is given in Table 11.
Results of Digestion and Metabolism Trials
In the last few weeks of the experiment each of the maintenance
lambs was subjected to a digestion and metabolism trial during which
feces and urine were quantitatively collected for 10 days. In each
case the lambs had been consuming for several weeks prior to the
collection period a constant daily amount of feed, the same as that
consumed during the time of collection of excreta. The excreta passed
during the first day in the metabolism crate were rejected. The meta-
bolism crates used have been described in Bulletin 283 from this Sta-
tion. The coefficients of digestibility for the different nutrients, com-
puted according to the ordinary method, have been summarized in
Table 12.
In addition to the routine analyses of feed and feces, the gross
energy was also determined in these samples, as well as in the urine,
by combustion in the bomb calorimeter. These determinations per-
mitted the computation of the metabolizable energy in the mainten-
ance rations (Table 13). The nitrogen balances of the lambs during
the metabolism trials are shown in Table 14. All lambs were storing
nitrogen.
An average of 59.7 percent of the gross energy of the ration was
metabolizable. Armsby has computed1 from his own experiments on
steers that the gross energy of alfalfa is 44 percent metabolizable and
that of corn 75 percent metabolizable. For a ration containing ap-
proximately equal amounts of gross energy from these two feeds, as
was true of the ration fed the maintenance lambs, one would expect
with steers that 59.5 percent (average of 44 and 75) of the gross
energy would be metabolizable, a value practically identical with the
average percentage actually obtained with the maintenance lambs.
Forbes and associates have recently reported2 some energy metabolism
studies on two steers receiving a ration containing equal parts of alfalfa
'Arinshy, H. P. Tho nutrition of farm animals, 661. Macmillan. 1917.
"Forbes, E. B., ct al. Amer. Soc. Anim. Prod. Proc., 1927.
1928}
THE MAINTENANCE AND FATTENING OF LAMBS
39
(iross energy
per gram
~ c: t- — < i.e rr.
£ — S -r J) -r
Z £. 'S '" ~
x ~. 5 c c^
i
-C
£
a
•~-
~ ' ':£ ' T
x ^* i^-
d -o :o
IIIII:K ,>s
03
X
c
s. ! . .
EH
H
•a
-: x r: x -t —
5; — — — X :S
o^re-t-
X
•o
ri
us
NANC
5. r- r- b- -,c ce
\
§1
— i-
i; x cr. ?1 £ £
ce M re s; re
•M
IN
O
H
a
a £
~ ~~
re re re re re
E
£
a
ii
X; "~e CT: f~ r- X
-• — < x -r M
M re — x t~
'c
'C
•HV.IS.S.
i 0 •- ~ - -0
7^ 7j re c*i 71!
o
c
O
Q
r t
>
2
_
re c-i re £. ri
»
=
£
~ -r -r ^r -r re
£SSE2
I
ic
O
i =
•g'S
^; re c: X ~ 7*
•2S7!qs
i
"E
r.
r1" £
i -i i-e -• — re
X C5 ~ c: X
1
i
s
0
^ ^
c
1
o
o
|
X=!5S3^ =
re t; -r •*? -^
s
w
H
G
"1
SSSSS
x x r^; * x
O
ID
re
1.
TABLE 1
Description of
feed sample
i'i^'C'u
I''ed at barn
Metabiilism trial1 . .
Metabolism trials2. .
Metabolism trials3. .
l'Vd at barn
— re
t_ —
i|
H
2~
= n
o
"3
Q
='-? S u
^ "T>I ^ ^ o
L=i! j3
•^ ^ t~ ^ —
'These sai
metaboliam trial
40 Buiuocr Na 3M
.-•'--" ~ - " - - - LAMBS
•rita
-
••MM
-
proteia
-
Crud«
-
-
• -
ft
'
!*«*•
fwnri.
-
•
1
-
sa
'
-. •
'
-
-
-
"
60
~
"»
-
-
".
-
"
~
!
gj
-
"
]
53
-
59
- -
"
-
i
-- :
-
gross
maintei cioi • . .' '
- , t. These 1 ~ sely with thos
-
Di:".v Iz:^ke c: Feed and E~ergy
i
ring the main1 \ r 100
- ~ ..• • • • .. • _ : " r - i Q to 1
100-: .
. * : to 100 and i ;• :. - ~".~ ::.e ral
-thini: f the weight of i tot two-thirds
100. _ body
=ize with i :o i - tsm v the 1 met
- - _
mus - . - . • . _ • . • . . _ - - 2 st g
horizontally Since :he — A.r.-enanre of these lambs involved both the
.
- is th< " :
T . _ " ould be
eriod
- •. - •
kings e ob-
tained only by «; v;^r.:ering and analyzing the maintenance lambs and
comparing '.heir : r.'.-rr.: o: energy with that of the check lambs, which
, - . - .
\
Composition of the Maintenance Lambs
iin-
tenance lan'r - ir- given in Tables 16. 17. 18. and 19. "With this group
-
-.
*—— - •----.'--•
-_;-£ r : - ~ •? '_ ^ _: •: - ;
Jt
-.- - - ------ Z ••—. —
— ^ - - - r - - : 5 — s
5.. 5 = .-------•;
.- 5 1 = •£--.-.-.--.-.- -
. - ^ . _. . _ . _ _
— -- " -
s
z =
"
z
- • - ~ ~ _ 2
: r " C I " • — 3
= - - - - • : -
. ;=-c-r-r r' — *
.-_ ^ - _ - ; _ _- _ - ^ -~-
L - ~ ~ ~ ^ ~ — '
~.
----- . - -
: -
- -
: ; • '
42
BULLETIN No. 314
[August,
1
co o co oo
(N O CO CO (O •*
^-H 050
!r>
co o> oo oo co i-i
CN rH
>
OOO-H
K3 "5 N CN T)< CO
(Nl> COOO
CO
SS&&3-
C^ CNCN
coSSSS
°^ ^§
00
T-l O 10 10 -H r-l
CO b* Oi O5 O5
' *^ CN N
OOOOO
I-IT)< O>CO
INOS oro
t~
iHf. CO CO CO 1-H
Mrt ^^
rH rH
>oirao>o
COCOCOl^Tfl
OOO t^O
•*
^SooS""1
C>'~t IN N
o >o 10 >o
iccc cooo
tO Tl" rH IO Tjl
000 Ng
CN
Sg§§8-
^^ CN-H
-t- —I
300 O ..
• • coo
INN
(NCOCOt^TjH ^H 00
.00 COCO
rH T)< 1-100 i-l ""
TfllH
1C »O O CO
< 00 U3 1C 1-1 r-l (Ni-i
•So •"Og-B-ooo.-.S;
:S^:§2l§2-gJ
;^|,a|aa|ig
« g g §^.2-2 ^.2-2
l!§a-glgg-2ss
a8^i-2-ssift-g
li-i-ilsg^;^
agss'gYj'g'si'S
Sa.S?SP"-S^^^ " 3 =
Ca)SS_aiO)ft E"§ ft ft
OM^P^MMgg^gg
? 2"3"3 0^.^00=500
&^^H^OO|00
C<;HH •« S
1928]
THE MAINTENANCE AND FATTENING OF LAMBS
43
TABLE 16. — SLAUGHTER DATA FROM THE MAINTENANCE LAMBS
(All weights in pounds)
136
85
75
22
10
25
11
43
Aver-
age
Live weight
72.8
72.4
69.0
71.7
69.4
71.6
73.2
74 9
71 9
Wool
2 80
4 00
3 90
5 25
4 50
6 65
4 75
4 91
4 60
Blood
2.80
3.25
4.10
3.70
2.90
3.20
3 00
3 17
3 27
8 50
7 20
5 70
6 50
5 15
6 35
6 66
6 83
6 61
Caul fat. .
.80
1.60
1.50
1 55
1 35
1 75
1 69
1 46
1 46
Gut fat
.80
1.10
1.35
1.25
1.40
1.10
1 24
1 02
1 16
Contents of first three
5.15
5 15
4.70
5 40
3 65
5 05
5 29
5 45
4 98.
Contents of 4th stomach
3 90
2 55
3 05
2 55
2 00
2 15
3 07
3 40
2 8$
Contents of entire
alimentary tract
Warm dressed carcass. .
Cold dressed carcass ....
Percent shrinkage
9.05
37.00
36.08
2.49
7.70
37.50
36.90
1.60
7.75
35.50
34.60
2.54
7.95
35.75
34.86
2.49
5.65
39.50
38.91
1.49
7.20
37.25
36.55
1.88
8.36
36.75
35.03
4.68
8.85
37.75
36.86
2.36
7.81
37.1$
36.22
2.44
Percent "fill"
12 4
10 6
11 2
11 1
8 1
10 1
11 4
11 8
10 8
Dressing percentage. . . .
49.5
51.0
50.2
48.6
56.1
51.1
47.8
49.2
50.4
TABLE 17. — WEIGHTS OF SAMPLES ANALYZED FROM THE MAINTENANCE LAMBS
Lamb
Empty
Edible flesh
Offal
Wnnl
No.
weight
Lean
Fat
Total
136.. .
kgs.
28.94
grams
10 767
grams
2 614
grams
13 381
grams
3 998
grams
8 838
grams
1 270
85
29 34
9 989
2 960
12 949
3 970
8 155
1 814
75.
27 76
10 677
1 740
12 417
• 4 178
8 672
1 769
22... .
10... .
25... .
11... .
43... .
Average..
28 . 94
28.91
29.21
29.43
29.96
29.08
10 427
10 399
10 136
9 59S
9 944
10 242
2 125
4 051
3 304
3 262
3 462
2 940
12 552
14 450
13 440
12 860
13 406
13 182
4 116
3 529
3 791
4 248
4 311
4 018
8 915
7 725
8 530
8 528
8 610
8 497
2 381
2 041
3 016
2 155
2 227
2 084
three instead of two samples were taken from each carcass besides
the composite wool sample for the group. The sample of edible flesh
represented the lean, including the kidneys, and the fat from the
dressed carcass. The bone sample included the bones of the dressed
carcass and the bones of the head and feet, as roughly cleaned with a
butcher knife. The offal sample contained the blood, the shorn skin,
and the flesh, brain, and eyes from the head, together with all viscera
and visceral fat.
It is evident from Tables 9 and 19 that the carcasses of the main-
tenance lambs were appreciably fatter than those of the check lambs.
On the live-weight basis the maintenance lambs contained 19.25 per-
cent of fat as compared with 11.90 percent for the check lambs; on
the basis of the empty weight these percentages were 21.57 and 14.15
respectively. The increase in weight of the maintenance lambs thru-
out their feeding period increased still further the storage of energy in
their bodies. Evidently the ration fed was appreciably greater in
energy value than the lambs required for the maintenance of energy
equilibrium. An attempt to correct the ration fed to energy equili-
brium has been made in Table 20.
44
BULLETIN No. 314
[August,
TABLE 18. — PERCENTAGE COMPOSITION AND ENERGY VALUE OF SAMPLES
ANALYZED FROM THE MAINTENANCE LAMBS
Lamb
No.
Dry
substance
Crude
protein
Ether
extract
Ash
Calcium
Calcium
in percent
of total
ash
Gross
energy
per gram
Edible flesh samples
136...
49 53
15 38
26 68
.91
.025
2.75
sm. cals.
3374
85
49.49
15.13
27.83
.82
.027
3.29
3612
75 .
41 32
16 63
21 91
89
026
2 92
3033
22
39 61
16 56
22 57
.87
.027
3. 10
3066
10
47.36
14.88
32.03
.77
.025
3.25
3777
25. .
45 47
15 38
30 31
.79
.030
3.80
3706
11
49 04
15 00
32.81
.76
.026
3.42
3820
43.
49 24
15 31
28 63
83
023
2 77
3551
Average. . . .
46.38
15.53
27.85
.83
.026
3.16
3492
Bone samples
136
60.79
59.90
58.66
58.24
57 . 84
60.40
55.74
57.74
58.66
19.17
19.52
19.51
19.38
18.96
19.38
18.02
19.31
19.16 -
17.96
19.77
18.44
17.31
16.71
20.86
19.77
18.59
18.68
20.90
18.78
18.64
18.73
19.55
18.21
16.41
18.35
18.70
7.84
7.09
7.03
7.00
7.33
6.72
6.14
6.99
7.02
37 . 5
37.8
37.7
37.4
37.5
36.9
37.4
38.1
37. 5
2862
3115
2905
2781
2679
3092
2816
2802
2882
85
75
22.
10
25
11. ..
43
Average. . . .
Offal samples
136
31.89
35.99
36.53
35.99
43.01
38.94
39.08
36. 3S
37.23
15.2.5
15.25
13.19
13.81
14.38
14.56
13.94
15.00
14.42
15.51
18.43
21.04
18.74
21.50
20.51
21.21
18.04
19.37
.91
1.09
.97
1.09
.99
.94
.98
1.05
1.00
.026
.030
.035
.023
.034
.026
.022
.029
.028
2.86
2.75
3.61
2.11
3.43
2.77
2.24
2.76
2.82
2319
2650
2674
2639
2914
2889
2811
2524
2678
85..
75
22
10
25
11
43...
1
Average. . . .
Wool samples
136-43
91.57
60.63
8.60
11.6
.177
1.53
4460
Changes in Energy Content of the Maintenance Lambs
The carcasses of the maintenance lambs contained an average of
89.9 therms of gross energy. Assuming that their energy content at
the beginning of the feeding period was the same as that of the check
lambs at slaughter, i.e., 894 calories per pound, the initial energy con-
tent of the maintenance lambs may be estimated; this has been done
in Table 20, giving an average estimate of 56.4 therms. Hence during
the period of feeding, the maintenance lambs added some 33.5 therms
of gross energy to their bodies at the rate of 252 calories per day. The
daily ration therefore provided 252 calories of net energy in excess of
the maintenance requirements. It may be estimated from Armsby's
data1 that the metabolizable energy of a ration consisting of equal
'The average gross energy of the alfalfa hay consumed by the maintenance
sheep was 4,108 calories per kilogram and that of the corn, 3.986 calories per
1928}
THE MAINTENANCE AND FATTENING OF LAMBS
45
TABLE 19. — PERCENTAGE COMPOSITION AND GROSS ENERGY
CONTENT OF THE MAINTENANCE LAMBS
Lamb
No.
Dry
substance
Crude
protein
Ether
extract
Ash
Calcium
Calcium
in percent
of total
ash
Gross
energy
per gram
On basis of live weight
136...
39.47
41.42
39.55
39.19
44.73 •
44.61
42.07
41.97
41.63
14.96
15.75
16.29
17.05
16.42
18.09
15.62
16.26
16.31
17.46
18.76
17.48
16.65
22.42
21.17
21.23
18.79
J9.25
3.58
3.53
3.77
3.85
3.54
3.78
3.40
3.68
3.64
.97
.88
.97
.92
.85
.82
.81
.91
.88
28.0
24.8
25.5
23.6
23.7
21.5
23.6
24.5
24.4
SOT. cals.
2 504
2 754
2 586
2 583
3 039
3 068
2 849
2 688
2 759
85
75
22 .
10
25
11
43
Average. . . .
On basis of empty weight
136
45.06
46.35
44.56
44.08
48.69
49.59
47.51
47.60
46.68
17.08
17.62
18.36
19.18
17.87
20.11
17.64
18.44
18.29
19.93
20.99
19.70
18.73
24.40
23.53
23.97
21.31
21.57
4.09
3.95
4.25
4.33
3.85
4.20
3.84
4.17
4.09
1.11
.99
1.09
1.03
.93
.91
.92
1.03
1.00
2 859
3 082
2 914
2 905
3 308
3 410
3 217
3 049
3 093
85
75 . ...
22
10
25
11
43
Average. . . .
parts of alfalfa hay and corn is 53 percent net available. Forbes and
associates (loc. cit.) have more recently investigated directly the utili-
zation of the energy of this ration on two steers. From the data ob-
tained it may be computed that the metabolizable energy equivalent to
one-half the maintenance requirement of steers, when added to a main-
tenance ration, increased the energy balance by an amount equal to
55.4 and 55.7 of the added metabolizable energy. In other words, be-
tween a maintenance level of feeding and a level 50 percent higher, the
metabolizable energy appeared to have a net availability of a little
over 55 percent. This percentage is in close agreement with the value
obtained from Armsby's data and has been used in the calculations of
Table 20.
Corrected Maintenance Requirements
Assuming, therefore, that the metabolizable energy consumed by
these lambs above their maintenance requirements possessed a per-
kilognim. Of the gross energy of alfalfa hay 44 percent is available as metaboliz-
able energy, and of corn 75 percent is available (see page 38). Of the metaboliz-
able energy in these feeds the percentage available as net energy for fattening is
(Armsby, "The Nutrition of Farm Animals,'' page 661) for alfalfa hay 39 percent
and for corn 61 percent. Each kilogram of alfalfa hay therefore, contained 4,108
X .44, or 1,808 calories of metabolizable energy, and 1,808 X .39, or 705 calories of
net energy: and each kilogram of corn contained 3,986 X .75, or 2.900 calorics of
metabolizable energy, and 2,900 X .61, or 1,769 calories of net energy. The aver-
age net availability of the metabolizable energy of a ration containing equal parts
705 + 1,769
of these two feeds is therefore
1,808 + 2,900
=52-55
46
BULLETIN Xo. 314
[August.
Average
O OTiS
— IS CM T
£0
CM CO to
— O T
iverage gross
it was found
nance lambs,
nergy intake,
•ed energy.
g
is t- >-* t-
?1 3 30 is CO T t- iS O
cote
t~iO
iS X x'
ft CCO
p had. The
•nance sheep
y the mainte
etabolizable <
valent of sto
iO
X
O T — CO
— O C X 01 iO b- iO O
CO b- OS >O CO IS T IS T
b- CO
§b-o — —
0 —
— i.o -r
le check shee
of the maint
• consumed b
s the daily in
e energy equ
iO
-H ocoo
— ' r- O O T TX iS M
CO O X iS M X X 'S T
— iS— CO
COM
M — X — —
T i.O M
CM X O
e weight as t
ibolism trials
1 gross energ;
by .filtS givi
inetabolizab
CO
CO CO T S:
iO 0 — is" O CX IS —
TO c; is co r~ T »o uo
— iS M T
C1CO
C: iO M — —
— —CO
• kilogram liv
uring the met
y. The tola
n multiplied
gy intake les>
.0
M
O OC 0
— e os o o -HO is T
CO t— S: iO T IO — i.O O
— is CO iS
f~ X CO — ' —
x s-. o
O CO M
~ " 5 'f. r
IN
•N
— S T X O iO X is C!
CO h- X iO M iO O i-O O
— iS — CO
~OT
the same gn
S(t4 calories p
ble as metal)
>f gross encrg
'Daily ineta
=
iS ~. T 0 X C T is p
O iO i.O t— i >— 1
—
M O — 'O
~ •£ '-; •£ t; '3 ~ '3 — '
*~< i-O CM 1*0
>0 X 0 -H —
CO —CO
O 'S CO
p at their initi
er kilogram of li
energy consun
lent gives the
bolizable energ
c.
3
: ; a
c
O
fc
.0
Feeding period, days
Average body weight, pounds
dross energy content, the! ins
Final
Initial'
( lain
Daily intake of metabolizable energy
calories2
Daily storage of energy, calories. . . .
Assumed availability of metabolizabl
energy of the ration, percent
Metabolizable energy equivalent of t
stored energy,3 calories
Maintenance requirements of metalx
energy daily, calories
Per bead*
J'er 100 pounds live weight:
Weight ratio
Surface ratio
Maintenance requirements of ration,!
per 100 pounds live weight:
Weight ratio
Surface ratio
'Assuming that the niaintenan
energy of the check sheep was 1971 ci
that an average of 5!).S percent of tl
divided by the number of days on
8Daily energy storage divided by . .r>5
192S] THE MAINTENANCE AND FATTENING OF LAMBS 47
centage availability of 55, the daily net energy stored, averaging 252
calories, may be taken as equivalent to 458 calories of metabolizablc
energy. The daily intake of metabolizable energy averaged 1,586
calories, so that the maintenance requirement becomes 1,586 — 458
=1,128 calories per head, or 1,637 calories per 100 pounds body weight
computed in proportion to weight, or 1,461 calories per 100 pounds
computed in proportion to the two-thirds power of the weight (body
surface). The quantity of feed has been computed from these values
by means of the average metabolizable energy content of the ration
(1,074 calories per pound).
The choice between the two estimates of the maintenance require-
ment of metabolizable energy is a difficult one, depending as explained
above on the proportions of energy used for the basal metabolism and
for muscular activity. These are unknown. It would be expected
that the more significant method of reducing these estimated require-
ments to a body weight of 100 pounds would give the less variable set
of values. The standard deviation of the estimates made in accord-
ance with the ratio of weights is 226 calories, while that of the esti-
mates made in accordance with the ratio of surfaces is 203 calories.
However, the coefficients of variation are practically the same, 14.4
and 14.5 percent respectively, so that a choice between the two meth-
ods on this basis can hardly be made.
On a ration of alfalfa hay alone it was found in the preceding
investigation with older sheep (see Illinois Bulletin 283) , that the main-
tenance requirement averaged, for 12 sheep, 1,820 calories of metabo-
lizable energy per 100 pounds live weight by using the ratio of weights,
and 1,733 calories by using the ratio of surfaces. These figures are ap-
preciably higher than those computed in the present experiment, a fact
that may reasonably be accounted for by the known poorer utilization
of the metabolizable energy of alfalfa hay than of corn.
Net Energy Required for Maintenance
Forbes and associates (loc. cit.) found that the metabolizable en-
ergy of a maintenance ration of equal parts of alfalfa hay and corn
was 80.8 percent net available for one of their steers (No. 47) and
81.4 percent net available for the other. If lambs may be assumed to
be equally efficient in the utilization of the metabolizable energy of
a similar maintenance ration, the net energy requirement of the lambs
may be computed for "economic maintenance." Applying the average
of the two percentages obtained with steers to the average metaboliz-
able energy requirements given in Table 20 gives a net energy require-
ment of 1,326 calories per 100 pounds live weight according to the
ratio of weights and 1,183 calories according to the ratio of surfaces.
Wood and Capstick1 have recently calculated by an indirect matho-
'Wood. T. B., and Capstick. J. W. Jour. Apr. Sci. 16, 325. 1926.
48
BULLETIN Xo. 314
[August,
matical method that a sheep weighing 100 pounds requires daily for
maintenance 1.26 pounds of starch equivalent, or 1,348 calories of net
energy. This value was computed in proportion to the surface of the
sheep and is therefore to be compared with the estimate of 1,183
calories in this experiment. Wood and Capstick obtained their value
by a mathematical analysis of data concerning the feed consumption
and the variations in weight of twenty-eight sheep. The starch values
of the feed consumed were apparently calculated from the average
tables of Kellner for fattening steers.
THE FATTENING EXPERIMENT
On September 30, 1925, eight lambs averaging 66 pounds in weight
were put upon such amounts of alfalfa hay and corn in equal propor-
tions as they would readily clean up. On October 24 a ninth lamb was
added to this group. These lambs were slaughtered at approximately
90 pounds in order to determine the nature of the gains made during
fattening to a popular slaughter weight and the utilization of the
metabolizable energy consumed and used for that purpose. The week-
ly weights of these lambs will be found in Table 21. The average daily
gains varied from .18 to .36 pound and averaged .25 pound.
The feed consumption of the lambs has been summarized and
averaged in Table 22. The feeds fed at the barns were sampled along
with the feeds of the maintenance lambs, and the analyses of these
samples have been given in Table 11.
TABLE 21. — WEEKLY WEIGHTS OF LAMBS DURING FATTENING PERIOD1
(All weights in pounds)
Lamb Xo
33
69
151
169
67
49
54
90
143
1927
Sept. 30
70
67
69
66
65
66
65
65
Oct. 10
69
69
73
69
55
67
69
66
17
68
71
68
70
55
67
66
66
24
65'
73
71
72
76
61
71
70
07
31
66
72
71
71
73
60
70
70
69
N'ov. 7
71
73
80
72
81
71
76
79
75
14
70
SO
77
78
78
69
78
76
72
21
73
80
78
76
78
69
75
74
73
28
73
85
77
79
80
66
76
77
73
Dec. 5
74
87
7!)
81
83
70
79
82
72
12
80
85
81
84
85
74
84
84
72
19
85
90
88
88
90
77
86
85
73
26
35
86
88
78
89
87
79
1926
Jan. 2
91
90
91
82
92
91
82
9
83
83
16
86
86
23
86
85
30
83
86
Feb. 6
85
90
13
87
17
90
Average weights
75 7
77.7
77 5
77 9
77.4
73 9
76 9
76 8
75 5
Average daily gains. . . .
Length of feeding period
.36
.24
.24
.'23
'.29
!l8
27
27
.'l9
in days
73
82
97
97
82
141
97
97
131
'Lambs 67 and 69 were slaughtered on December 21, 1925, after 82 days of feeding; Lambs
151, 169, 54, 33, and 90 were slaughtered on January 5, 1926, after 97 days of feeding; Lamb 143 was
killed on February 8, and Lamb 49 on February 18, after 131 and 141 days of feeding, respectively.
1928]
THE MAINTENANCE AND FATTENING OF LAMBS
49
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50
BULLETIN No. 314
[August,
Results of the Digestion and Metabolism Trials
During the period from October 29 to December 5 digestion and
metabolism trials were made upon five of the nine fattening sheep. As
with the maintenance lambs, the collection periods were of 10 days
duration. For two of the lambs (Nos. 69 and 169) no change in feed
had been made for 29 days before the collection period. For Lamb
33 the feed had been constant for nine days preceding the digestion
experiment, while for Lambs 67 and 151, it had been raised from 2.0
to 2.4 pounds daily on the second day preceding the collection period.
The latter two lambs should not have been put on a digestion exper-
iment so soon after a change of feed, but nevertheless the results ob-
tained in these cases agreed well with the results obtained upon the
other lambs. Except on the final day of collection with Lamb 67, there
was no refused feed in these digestion experiments.
The chemical composition of samples of feed taken during the
digestion and metabolism trials is given in Table 23. The alfalfa hay
fed in these trials was somewhat drier than that fed at the barn (see
Table 11) and somewhat higher in protein, but the corn fed was very
similar in composition to the composite samples taken at the barns.
In Table 24 the coefficients of digestibility of the nutrients in the
ration, as computed in the ordinary way, have been summarized. A
comparison of the average coefficients obtained with these fattening
lambs and those obtained with the maintenance group consuming the
TABLE 23. — CHEMICAL COMPOSITION OF FEED CONSUMED BY THE FATTENING LAMBS
DURING DIGESTION AND METABOLISM TRIALS
Dry
Gross
Lamb No.
sub-
stance
Crude
protein
N-free
extract
Crude
fiber
Ether
extract
Ash
Cal-
cium
energy
per
gram
Alfalfa hay
69, 169..
perct.
92 67
perct.
18 25
perct.
41 97
perct.
22 03
perct.
2 34
perct.
8 08
perct.
sm. cals.
4172
67, 151
93 54
17 38
39 67
25 11
2 17
9 21
1 44
4215
33
93.51
17.06
43.61
22.98
2.37
7.49
1.52
4158
Corn
69, 169
88 93
8 56
73 55
2 19
3 37
1 96
3984
67, 151.. .
87 54
8 73
71 86
2 50
3 18
1 27
3935
33
87.56
8.56
72.09
2.23
3.54
1.14
3918
TABLE 24. — DIGESTION COEFFICIENTS OBTAINED WITH THE FATTENING LAMBS
Lamb
No.
Dry
substance
Crude
protein
N-free
extract
Crude
fiber
Ether
extract
69
perct.
77
perct.
73
perct.
89
perct.
36
perct.
66
169
75
71
88
28
65
67
76
70
89
35
62
151
76
72
89
36
62
33....
75
68
87
49
60
Average
75.8
70.8
88.4
35.4
63.0
THE MAINTENANCE AND FATTENING; OF LAMBS 51
same ration at a different level may be made by turning to Table 12.
In general a higher digestibility was obtained with the fattening lambs.
The determination of the gross energy of feed and excreta in these
digestion experiments permits the calculation of the metabolizable
energy content of the ration, the methane excretion being estimated,
according to Armsby's method for steers, from the digestible carbo-
hydrates consumed. These calculations will be found in Table 25.
For the fattening lambs the ration contained 2.794 therms per kilo-
gram of dry matter, as compared with an average of 2.653 therms ob-
tained with the maintenance lambs (Table 13). For the fattening
lambs the gross energy of the ration was 62.27 percent metabolizable
on the average, as compared with 59.74 percent, for the maintenance
lambs.
The fattening lambs were all storing nitrogen during the collec-
tion periods according to the data assembled in Table 26.
Composition of the Fat Lambs
At the end of feeding periods varying in length from 73 days to
141 days, the nine fattened lambs were slaughtered at weights of ap-
proximately 90 pounds. The method of sampling was essentially the
same as that followed with the maintenance lambs. For each lamb
there were three samples consisting of edible flesh, bone, and offal, and
for all lambs slaughtered on the same day a composite sample of wool
was taken. Slight irregularities in the disposition of the bones of the
head and feet, as between the bone and the offal samples, resulted thru
inadvertance, but these did not affect the accuracy of the final com-
putations. These irregularities are all noted in the tables. The slaugh-
ter data for these lambs, the weights of samples, the results of the
analysis of the samples, and the estimated composition of the total
animals on the live-weight and empty-weight basis are given in Tables
27 to 30. The latter computations, as for all preceding groups of
lambs, include all possible corrections for losses of moisture during
slaughtering and sampling.
The fat lambs contained an average ''fill" of 11.1 percent, as com-
pared with averages of 15.9 for the check lambs and 10.8 for the main-
tenance lambs. On the basis of the empty weight the fat lambs con-
tained an average of 24.89 percent of fat, the maintenance lambs 21.57
percent, and the check lambs 14.15 percent. The average ash percent-
ages for the three groups of lambs on the same basis were 4.17, 4.09,
and 4.79 respectively. The percentage of calcium in the ash of the
empty carcass averaged 22.3 for the fat lambs, 24.4 for the mainten-
ance lambs, and 28.5 for the check lambs. The first group of check
lambs also showed a high average for this value, i.e., 27.4 percent. In
the case of rats, Buckner and Peter1 obtained fairly constant percent-
'Buckner, G. D., and Peter, A. M. Jour. Biol. Chem. 54, 5. 1922.
52
BULLETIN No. 314
[August,
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THE MAINTENANCE AND FATTENING OF LAMBS
53
TABLE 26. — DAILY NITROGEN BALANCES OF THE FATTENING
LAMBS DURING METABOLISM TRIALS
Lamb
No.
Nitrogen of
feed consumed
Nitrogen of
feces
Nitrogen of
urine
Total N
excreted
Nitrogen
balance
69...
grams
19.49
grams
5.20
grams
10.15
grams
15.35
grams
+4.14
169
19.49
5.70
10.39
16.09
+3.40
67
22.72
6.90
11.17
18.07
+4.65
151
22.72
6.26
12.53
18.79
+3.93
33
18.62
5.89
9.72
15.61
+3.01
TABLE 27. — SLAUGHTER DATA FOR THE FATTENED LAMBS
(All weights in pounds)
Lamb No
67
69
151
169
54
33
90
143
49
Live weight ....
Wool . .
87. 4
5 13
88.7
5.94
85.5
4 74
87.8
6.26
87.8
4.84
84.9
4.39
88.8
4.76
85.4
5.35
84.1
5.60
86.7
5 22
Blood
3.56
3.50
3.80
7.67
3.72
2.94
3.56
3.20
3.05
3 89
Skin and feet . .
Caul fat .
7.44
1 75
7.00
2 69
8.55
1.85
6.35
2 34
9.19
1.39
7.56
1.65
8.13
2.18
6.65
2.20
7.00
2 90
7.54
2 11
Gut fat. . . .
.81
.81
.80
.95
.70
1.00
1.02
1.65
1.45
1.02
Contents of
first three
stomachs ....
Contents of 4th
stomach and
intestines. . . .
Contents of
entire alimen-
tary tract. . .
Warm dressed
8.44
2.56
11.00
46.38
8.81
3.00
11.81
44.94
6.25
2.85
9.10
44.75
4.86
3.01
7.87
45.75
7.94
3.41
11.35
43.75
7.58
2.85
10.43
43.50
5.94
3.25
9.19
46.50
4.55
2.80
7.35
47.00
6.80
2.10
8.90
46.00
6.80
2.87
9.67
45.40
Cold dressed
carcass
45.90
44.35
43.33
44.20
42.26
41.85
44.88
45.93
45.07
44.20
Percent
shrinkage ....
Percent "fill". .
Dressing
percentage. . .
1.03
12.6
52.5
1.31
13.3
50.0
3.17
10.6
50.7
3.39
9.0
50.4
3.41
12.9
48.1
3.79
12.3
49.3
3.48
10.4
50.6
2.28
8.6
53.8
2.02
10.6
53.6
2.65
11.1
51.0
TABLE 28. — WEIGHTS OF SAMPLES ANALYZED FROM THE FATTENED LAMBS
Lamb
Empty
Edible flesh
Offal
Wool
No.
weight
Lean
Fat
Total
kgs.
grams
grams
grams
grams
grams
grams
67.
34.65
12 108
5 640
17 748
2 703'
10 989
2 327
69.
34.87
12 021
4 974
16 995
2 753'
10 747
2 694
151.
34.65
11 726
4 215
15 941
4 008 2
10 657
2 150
169.
36.24
10 738
5 682
16 420
3 88N =
11 101
2 839
54.
34.70
12 025
3 452
15 477
4 0072
10 978
2 195
33.
33.77
11 433
3 737
15 170
4 0702
10 635
1 991
90.
36.09
11 918
4 452
16 370
4 0142
10 890
2 159
143.
35.43
12 368
5 175
17 543
4 514
9 420
2 427
49.
34.11
10 584
5 885
16 469
3 825
9 910
2 540
Average..
34.95
11 658
4 801
16 459
2 369
•Exclusive of bones of head and of feet, which were put in the offal sample. 8>Jot including
bones of feet, which were put in offal sample.
ages of 25 to 26 thruout the growing period. The bone samples of both
the fat lambs and the maintenance lambs contained normal average
percentages of calcium in the ash (37.6 and 37.5 respectively). The
low ash content of the bone samples as compared with that of well-
calcified bone itself is to be expected in view of the imperfect separa-
tion of bone from soft tissues in the preparation of these samples.
54
BULLETIN No. 314
[August,
TABLE 29. — PERCENTAGE COMPOSITION AND ENERGY VALUE OF SAMPLES
ANALYZED FROM THE FATTENED LAMBS
Lamb
No.
Dry
substance
Crude
protein
Ether
extract
Ash
Calcium
Calcium
in percent
of total
ash
Gross
energy
per gram
Edible flesh samples
67 ...
51.69
13.56
36.86
1.31
.020
1 53
sm. cals.
4 196
69
51.66
13.19
35.84
1.18
.021
1.78
4 061
151 .. .
53.61
14.00
37.60
1 03
.018
1 75
4 292
169
52.14
14.56
34.23
.98
.017
1.73
4 000
54
54.19
15.56
28.60
1.07
.027
2.52
3 421
33
53.38
15.63
28 11
1 41
021
1 49
3 422
90
51.39
14.31
32.94
1.03
.020
1.94
3 794
143
48.88
15.13
33.54
.83
.021
2.53
3 968
49 ..
58.59
14.13
39.64
.73
025
3 42
4 398
Average. . . .
52.84
14.45
34.15
1.06
.021
2.08
3 950
Bone samples1
67...
70.42
19 81
22.59
24.75
9.34
37 7
3 349
69
69.66
18.86
21.79
24.26
9.22
38.0
3 391
151
57 67
17 69
18 95
19 35
7 25
37 5
2 854
169
60 79
18.52
18.87
20.32
7.75
38.1
2 904
54
58.19
18.30
16.56
21.02
7.88
37.5
2 643
33
58 09
16 51
19 00
19.35
7 24
37 4
2 830
90
59 32
18.30
17.93
20.80
7 76
37 3
2 796
143
60.69
20.41
16.23
21.79
8.20
37.6
2 742
49
60 42
21 27
16 25
21 81
8 17
37 5
2 720
Average. . . .
61.69
18.85
18.69
21.49
8.09
37.6
2 914
Offal samples2
67 ....
39 35
14 50
20.05
2.24
.519
23.2
2 759
69
38.06
14 . 56
17.13
2.39
.559
23.4
2 527
151
36 99
14 69
19 87
1 16
.061
5 26
2 576
169 .
37 94
14 13
21 98
1.14
.061
5.35
2 669
54
34.48
15.75
17.00
1.28
.076
5.94
2 327
33
35 99
15 50
19 08
1 31
102
7 79
2 563
90 ... .
38 46
14.69
20.63
1.14
.090
7.89
2 658
143
41.27
14.94
23.64
.92
.021
2.28
3 027
49
42 99
14 69
24 83
.95
.023
2 42
3 166
Average. . . .
Wool samples
67, 69. ...
89 35
60.75
9.05
11.34
.20'
4 344
151, 169, 54,
33, 90
143, 49
89.73
89.62
60.88
60.84
8.83
8.89
15.54
14.34
.203
.203
4 366
4 374
'The samples for Lambs 67 and 69 contained only the bones from the dressed carcass; those for
Lambs 151, 169, 54, 33, and 90 contained in addition the bones of the head; while those for Lambs
143 and 49 contained the bones of head and feet. 2The samples for Nos. 67 and 69 contained
the bones from the head and feet; those for Nos. 151, 169, 54, 33, and 90 contained the bones of the feet;
while those for Nos. 143 and 49 contained only the viscera and other waste. 3The average calcium
content of a composite sample of wool from all fat sheep.
In Table 30, the nine fat lambs are arranged in the order of their
slaughter. No progressive differences in composition are evident, so
that the data obtained do not indicate that the rapid gains are ap-
preciably different in composition from the slow gains.
Composition of the Gains in Weight
On the assumption that the fat lambs at their initial weights
possessed the same composition on the live-weight basis as the second
IMS]
THE MAINTENANCE AND FATTENING OF LAMBS
55
TABLE 30. — PERCENTAGE COMPOSITION AND GROSS ENERGY
CONTENT OF THE FATTENED LAMBS1
Calcium
Gross
Lamb
No.
Dry
substance
Crude
protein
Ether
extract
Ash
Calcium
in percent
of total
energy
per gram
ash
On basis of live weight
67...
44.10
15.01
24.14
3.56
.80
sm. cats.
2 492
69
42 74
14 82
21 82
3 56
80
2 914
151
43 14
15 00
23 37
3 61
78
3 010
169
44.43
16.10
22 47
3.82
.79
2 988
54
41.34
15.58
17.96
3.74
.84
2 476
33
41 76
15 33
18 82
3 77
81
2 582
90
42 02
14.89
21 24
3 61
.82
2 775
143
44.84
16.65
23.37
4.03
.98
3 125
49
48 49
16 10
25 78
3 70
85
3 285
Average. . . .
43.65
15.50
22.10
3.71
.83
2 849
On basis of empty weight
67 .
50 45
17 17
27 61
4 07
92
22 6
2 851
69
49 31
17 10
25 17
4.10
.93
22 7
3 361
151
48.28
16 78
26 15
4.04
.87
21.6
3 368
169
48 80
17 68
24 96
4 19
87
20 7
3 284
.~)4 .
47 48
17 88
20 61
4 29
96
21 9
2 844
33
47.61
17 48
21 45
4.29
.93
21.7
2 943
90
46.88
16.60
23.69
4.03
.91
22.2
3 095
143
49 06
18 23
25 57
4 41
1 07
24 3
3 419
49 . ...
54.22
18 01
28 84
4 14
.95
22.9
3 674
Average. . . .
49.12
17.43
24.89
4.17
.94
22.3
3 205
'Xos. 67 and 69 were killed after 82 days of feeding; 151, 169, 54, 33, and 90 after 97 days; 143
after 131 days; and 49 after 141 days of feeding.
group of check lambs (Table 9), it is possible to compute the compo-
sition of the gains put on during the fattening period. The results of
such a calculation, expressed as percentages of the estimated increase
in empty weight, are given in Table 31. The great variation among the
individual estimates is due not only to the differences in the actual
composition of gains but also to the not inconsiderable error in the
method of estimation, according to which all of the lambs are assumed
to possess the same initial composition.
The average gain in empty weight from about 65 to about 90
pounds contained 75.1 percent of dry matter, 11.9 percent of crude
TABLE 31. — ESTIMATED PERCENTAGE COMPOSITION AND ENERGY VALUE
OF GAINS IN EMPTY WEIGHT PUT ON BY THE FATTENED LAMBS
Lamb
Xo.
Dry
substance
Crude
protein
Ether
extract
Ash
Gross energy
per pound
67
79.8
10 9
63 4
2 1
therms
3 11
69
81.8
9.2
61.2
1 8
3 03
151
73 3
9 1
59 9
2 0
2 83
169
73.7
12.9
53 7
2 6
2 62
54
68.8
13.5
37.6
3.0
1 89
33
70 3
11.8
41 5
2 9
2 08
90
63.3
10.2
44.6
2 3
2 15
143
71 5
15 3
52 2
3 6
2 68
49
93.3
14.0
67.8
2 5
3.27
Average
75.1
11.9
53.6
2.5
2.63
56
BULLETIN No. 314
[August,
protein, 53.6 percent of fat, and 2.5 percent of ash. The computations
for calcium indicated no increase in the store of this mineral. The nine
lambs contained an average of 327 grams of calcium at slaughter and
were estimated to have contained an average of 344 grams initially. It
seems improbable that no calcium was stored during the fattening
period. A slight storage, however, may have been obscured by the
possible error in the estimation of the initial calcium composition of
the lambs.
Each pound of gain in empty weight contained on the average
2.63 therms of gross energy. This value is less than the average value
of 3.25 therms given by Armsby to the energy content of a pound of
gain by fattening animals, but is almost identical with the value re-
ported by Wood1 for two sheep gaining from an average of 87 to one
of 124 pounds in body weight, i.e., 2.64 therms. In Bulletin 283 from
this Station the average energy value of a pound of gain in empty
weight from 87 to 117 pounds was found to equal 2.58 therms. Ap-
parently the weight increase of sheep is remarkably constant in energy
content, largely because it is fairly constant in fat content. In this
experiment the average fat content was 53.6 percent; in the preceding
experiment at this Station it was found to be 47.7 percent, and in
the experiment of Wood it averaged 50.7 percent (on the increase in
live weight). The crude protein percentages were not so constant,
averaging 11.9, 13.2, and 17.6 respectively for the three experiments.
Distribution of Added Nutrients in the Carcasses
It is of interest to compute the distribution of the added nutrients
among the dressed carcass, the offal, and the wool. Such calculations
are complicated somewhat by the different methods of making up the
samples for the check and fat lambs, but satisfactory results may be
obtained on the assumption that the head and feet bones possessed
the same chemical composition as the bones of the dressed carcass.
TABLE 32. — PERCENTAGE DISTRIBUTION OF GAINS IN CHEMICAL CONSTITUENTS OF
THE FAT LAMBS AMONG DRESSED CARCASS, WOOL, AND OFFAL
Dry
substance
Crude
protein
Fat
Ash
Gross
energy
Dressed carcass. . .
Wool
66.7
s s
54.8
26 3
71.4
2 1
15.3
64 9
69.6
5 2
Offal
24 . 5
18.9
26 o
19 8
25 2
Total
100.0
100.0
100.0
100.0
100.0
The weights of head and feet bones were obtained for the fat lambs,
so that the composition of the dressed carcass can be approximated.
The results obtained on this question are assembled in Table 32.
'Wood, T. B. Jour. Min. Agr. [Gr. Brit.] 34, 295. July, 1927.
THE MAINTENANCE AND FATTENING OF LAMBS 57
With the exception of the added mineral matter the dressed car-
cass received most of the nutrient material added to the bodies of the
lambs during their fattening period. An average of 66.7 percent of the
added dry matter, 54.8 percent of the added protein, 71.4 percent of
the added fat, 15.3 percent of the added mineral matter, and 69.6 per-
cent of the added gross energy were found in the dressed carcasses of
these lambs. The added wool contained about two-thirds of the added
mineral matter and about one-fourth of the added protein but very
little of the added energy. The mineral matter found in the wool con-
tained only a trace of calcium and probably consisted of dirt to a large
extent. The failure of these lambs to increase in calcium content altho
increasing in mineral content is thus partially explained.
The main difference in the disposition of added nutrients in the
carcass between these young lambs and the more mature sheep of the
preceding experiment1 relates to the protein. In the former experiment
60 percent of the added protein was found in the wool, the growth of
the carcass being largely completed. In the present experiment less
than 20 percent of the added protein was found in the wool, the dressed
carcass alone containing about 55 percent and the offal parts over
25 percent.
With the more mature sheep, wool growth accounted for greater
percentages of all added nutrients than with the growing lamb. It was
also formed at a much more rapid rate, being equivalent to a daily
growth of .149 pound of protein and 566 calories of gross energy per
day per 1,000 pounds live weight. In the experiment on growing lambs
the daily growth of wool contained an average of only .086 pound of
protein and 377 calories per 1.000 pounds live weight.
Utilization of Feed Energy in Fattening
The relation between the feed energy consumed by the fattening
lambs and their average daily retention of energy is of interest in
throwing light upon the efficiency of utilization of energy by sheep.
The calculations given in Table 33 are concerned with this relation.
The average energy content of the lambs at slaughter was 114.8 therms.
Their initial content, as computed from the initial weights and the
average energy content of the second group of check lambs per unit
of live weight, averaged 59.4 therms. The gain in energy therefore
averaged 55.4 therms, or 568 calories, daily. The average daily intake
of metabolizable energy was 2,427 calories, of which 1.254 calories
were estimated to have been used for maintenance. This estimate is
based upon the average weight of the lambs during the feeding period
and the average metabolizable energy requirements for maintenance
as previously determined, i.e., 1,637 calories per 100 pounds live weight.
'111. Agr. Exp. Sta. Bui. 283, 243, Table 25.
58
BULLETIN Xo. 314
[August,
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1928] THE MAINTENANCE AND FATTENING OF LAMBS 59
the direct ratio of weights being used. Hence, according to these fig-
ures 1,173 calories of metabolizable energy may be considered as avail-
able for production. The production secured averaged 568 calories
daily, or an average of 48.5 percent of the metabolizable energy avail-
able.
As previously mentioned (page 45), experimental work with steers
indicates a percentage availability of metabolizable energy of 53 to 55
for a ration of equal parts of corn and alfalfa hay. The results of this
experiment point, therefore, to a somewhat less efficiency on the part
of the sheep as compared with the steer in the utilization of metaboliz-
able energy. For alfalfa hay alone results have been reported previ-
ously for sheep (Bulletin 283) that are equal to several reported by
Armsby for steers but inferior to some of the later results.
SUMMARY
The digestibility of a ration consisting of equal parts by weight
of alfalfa hay and shelled corn was investigated at two levels of feed-
ing, one representing but little more than a maintenance ration (eight
lambs) and the other representing full feed (five lambs). The coeffi-
cients of digestibility at the higher level were generally greater than
those at the lower, altho the differences were not large. At the higher
level 62.3 percent of the gross energy of the ration was found to be
metabolizable, while at the lower only 59.7 percent was metabolizable.
The metabolizable energy of the ration per kilogram of dry matter was
2.794 therms at the higher level, and 2.653 therms at the lower. For
steers the gross energy in a ration of equal parts of corn and alfalfa
hay has been found to be 60 to 61 percent metabolizable.
In feeding tests upon eight lambs averaging 69 pounds in weight,
the maintenance requirements in terms of pounds of feed and of
metabolizable energy per 100 pounds of weight have been determined
for a ration containing equal parts of alfalfa hay and corn. The data
of feed consumption, feed analyses, and digestion and metabolism
trials have been supplemented by carcass analyses of check lambs
and of the maintenance lambs at the end of their feeding period, in
order to correct for a storage of energy in the body. It was found that
1.53 pounds of feed and 1,637 calories of metabolizable energy were
required per 100 pounds weight for the maintenance of energy equi-
librium. These values may be compared with those determined in a
previous experiment for a ration of alfalfa hay alone, i.e., 2.29 pounds
and 1,820 calories of metabolizable energy.
Nine lambs were used in a fattening experiment to determine the
efficiency in the use of metabolizable energy for production. These
lambs were fattened from about 65 pounds in weight to about 90
60 BULLETIN No. 314
pounds, at which weight they were slaughtered and analyzed. Di-
gestion and metabolism experiments were run upon five of these lambs.
Altho the daily rate of gain varied from .18 to .36 pound, no
relation could be detected between the rate of gain and the composition
of the carcass. On the average the fat content of the empty carcass
increased from 14.15 percent, as determined by the analysis of eight
check lambs at approximately the initial weight, to 24.89 percent.
The average gain in empty weight was calculated to possess the
following composition: 75.1 percent of dry matter, 11.9 percent of pro-
tein, 53.6 percent of fat, and 2.5 percent of ash. Its gross energy value
was 2.63 therms per pound.
Altho the ash content of the lambs increased during fattening, no
increase in the calcium content could be demonstrated. A small in-
crease might well have been obscured by the possible error in the
slaughter experiment. The absence of any indication of a large in-
crease in calcium was due to two factors. In the first place, 65 percent
of the increase in ash occurred in the wool, and largely represented
outside contamination. Again, the percentage of calcium in the ash of
the entire carcass decreased from 27.4 to 28.5 in the check lambs to
22.3 in the fattened lambs, the maintenance lambs showing an average
of 24.4.
The gains in nutrients by the fat lambs were largely added to the
dressed carcass. Thus 66.7 percent of the dry matter of the gains,
54.8 percent of the protein, 71.4 percent of the fat, and 69.6 percent
of the gross energy gained were deposited in the dressed carcass. The
wool growth accounted for 8.8 percent of the dry matter gained, 26.3
percent of the protein. 2.1 percent of the fat, and 5.2 percent of the
energy.
The daily wool growth of these young lambs contained per 1,000
pounds live weight .086 pound of protein and 377 calories. These
values are only about 60 percent as large as those obtained with larger
and older sheep in a previous experiment.
The daily gain of energy by the fattening lambs averaged 568
calories. The average intake of metabolizable energy was 2,427 cal-
ories daily, of which 1,254 calories were estimated to have been re-
quired for maintenance. The difference, 1,173 calories, may therefore
be compared with the energy storage to determine the efficiency of
utilization of the metabolizable energy consumed in excess of the
maintenance requirements. The daily storage of 568 calories is 48.5
percent of the metabolizable energy apparently available for this pur-
pose. We may say, therefore, that between a maintenance level of
feeding and the full- feed level attained by the fattening lambs, the
metabolizable energy of the ration of alfalfa hay and corn was 48.5
percent net available. For steers a utilization of 53 to 55 percent
would be expected for this ration.
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