station (table 3). Acid detergent lignin was not 
completely recovered in any of the studies re- 
ported. Apparent digestibility of acid detergent 
lignin in alfalfa hay was approximately 10 
percent; however, average values in various 
trials ranged from about 7 to 13 percent. In the 
studies of McCann and Theurer (1967), appar- 
ent digestibility of acid-detergent lignin 
ranged from —8 to 17 percent for individual 
steers fed alfalfa hay in two trials. 
TABLE 3.—Apparent percent digestibility of 
acid detergent lignin by cattle fed alfalfa hay 
(88 percent) of lignin in the fecal samples. Av- 
erage percent of fecal lignin did not differ be- 
tween grab samples and total collection sam- 
ples, but day-to-day fecal lignin concentration 
was significantly different (P < .05). McCann 
(1967) ° estimated that four steers and 3 days 
were required to estimate dry-matter digest- 
ibility using the lignin-ratio technique with a 
95-percent confidence interval of +10 units of 
the mean with a probability of 95 percent. Van 
Dyne and Lofgreen (1964) estimated that 
three animals (sheep or cattle) were required 
to estimate dry-matter digestibility within 10 
percent of the mean with 90 percent confi- 
dence; the average numbers of forage plus 
fecal animals (sheep or cattle) required to esti- 
mate digestion coefficients for crude protein, 
ether extract, other carbohydrates, or cellulose 
were 29, 25, 6, and 5. 
TABLE 4.—E'stimated percent dry-matter di- 
gestibility determined by lignin-ratio technique 
Number of Appar- 
ent 
Ani- Obser- digest- 
Investigator mals vations ibility 
Trei & Hale (1965)* ___- 4 24 7.6 
Amavisea (1966)* -____- 8 12 12.6 
Lambeth (1966)* _____--- 12 12 11.8 
McCann and Theurer 
(1967) Mees eee 8 16 12.0 
Loynachan (1968)? _-____ _ 12 12 6.8 
Total or average __--- 44 76 10.1 
‘Trei, J. E., and Hale, W. H., 1965, Unpublished 
data on file at Univ. Ariz., Tucson, Ariz. ’ 
* Unpublished M.S. Thesis, Univ. Ariz., Tucson, Ariz. 
Lesperance et al. (1967) reported apparent 
digestion coefficients for acid detergent lignin 
of —45 +25 percent and —29 +18 percent in 
studies with steers fed freshly cut grass. It is 
not clear whether these large negative values 
were associated with the type of forage or with 
some factor unique in this study. Using the 
72-percent sulfuric acid method of Ellis et al. 
(1946) for lignin determination, other workers 
have noted incomplete recovery of lignin of 
from 1 to 24 percent (Kane et al. 1950; Balch 
1957; and Elam and Davis 1961). Incomplete 
recovery of lignin will bias nutrient digestibil- 
ity values downward. More studies are needed 
to determine recovery of acid detergent lignin 
from animals with several forage species vary- 
ing in moisture content. An accurate estimate 
of lignin recovery is necessary to obtain mean- 
ingful digestibility coefficients with the lignin- 
ratio technique. Although complete recovery of 
lignin is desirable, it is not necessary since ap- 
propriate correction factors may be effectively 
used (Lucas 1952) if percent recovery can 
be adequately determined. 
McCann and Theurer (1967) compared dry- 
matter digestibility estimated by acid-deter- 
gent lignin with actual values obtained from 
steers fed alfalfa hay (table 4). Dry-matter di- 
gestibility values obtained by the lignin-ratio 
technique using total fecal collection or single 
daily fecal grab samples were similar but dif- 
fered significantly (P < .05) from actual di- 
gestibility determined by total collection. This 
difference was due to the incomplete recovery 
114 
Lignin-ratio technique 
Trial Total Fecal 
Total feces grab 
Steers collection samples samples * 
1 8 ° 58.4 *53.8 *52.8 
2 8 *62.8 *56.6 Siti 
Average ° 60.6 455.2 *55.0 
*McCann and Theurer (1967). 
“Once daily at 7:00 a.m. 
** Means on same line with unlike superscripts differ 
significantly (P<0.05). 
ESTIMATION OF FECAL EXCRETION 
AND FORAGE INTAKE 
Fecal output from grazing animals can be 
measured directly by means of harness and col- 
lection bags (Garrigus and Rusk 1939), but 
this equipment may influence grazing behavior, 
cause the animal considerable distress, and in- 
crease the energy expenditure. Loss of fecal 
material from collection bags may be excessive 
if the bags are not carefully adjusted for each 
animal and if the bags are not emptied fre- 
quently (often two or three times daily). 
The animal must be thoroughly accustomed to 
the collection apparatus if the intake data ob- 
tained is to be meaningful. The results of Hill 
et al. (1961) indicated that feces production 
may be overstimulated when collection bags 
are used intermittently for 4-, 6-, or 24-hour 
collections. Meyer et al. (1956) found that the 
average daily gain of steers fitted with a fecal- 
collection harness was significantly less than 
for those without a harness. It was suggested 
*McCann, C. P. 1967. Nutritional studies using 
chromic oxide and lignin ratio techniques with rumen 
fistulated versus intact steers. Unpublished M.S. The- 
sis, University of Arizona, Tucson, Arizona. 
