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RUMEN DIGESTION
[Vol. XXVIII, Pt. IV,
Factors in cellulose digestion
Cellulose digestion is also affected by different factors. According to Cline
[1952], Hunt [1952] and Brooks et al. [1954a] sulphur in the diet increases cellulose
digestion.
Brooks et al. [1954a] has shown that 10 to 20 mgms of stilboesterol
in diet per day increase the digestion coefficient of cellulose by 6 to 7 per cent. Brooks
et al. [1954b] has also shown that fat reduces cellulose digestion. Zuntz [1913],
Armsby and Fries [1918], Mertins [1933], Mitchell and Hamilton [1940], Hamilton
[1942], Johnson et al. [1942] and Burroughs et al. [1950] have demonstrated
that a readily available form of carbohydrates such as starch has the tendency to
shift the field of bacteria activity and thereby decreasing cellulose digestion. Molas-
ses, glucose and grain diet decrease the cellulose digestion as has been effectively
demonstrated by Bortree et al. [1948] and Arias et al. [1951]. Burrough et al.
[1949, 1950, 1951] has studied the effects of mineral requirements on cellulose diges-
tion in cattle. He and his co-workers have effectively demonstrated that absence
of Na, K, Ca, Mg, S, P, and Fe singly or in group decreases cellulose digestion.
Chappel [1952], Teeri et al. [1953], Ray [1953], Tillman et al. [1954a, 1954b] and
Charles et al. [1955] have confirmed the findings of Burroughs et al ;
these investigators have demonstrated that poor roughage diet can be effectively
utilized by cattle with mineral supplements—a fact which is highly important from
the point of view of economics of feeding and which has lead to the preparation of
mineral supplements for ruminants. [Beeson and Perry, 1953 ; Klosterman, 1953].
Burroughs et al. [1950] has also demonstrated that soyabean oil meal, linseed oil
meal, wheat bran, and cotton seed meal in cows increase cellulose digestion while
meat scrap, fish meat and oats decrease cellulose digestion. Hoflund [1949] has also
demonstrated that late harvest hay has a tendency to increase cellulose digestion.
That protein and vitamin B 12 deficiency for long periods tend to decrease cellulose
digestion has been demonstrated by Hall et al. [1953]. Burroughs et al. [1950, 1951],
Doetsch et al. [1952], Huhtanen et al. [1952], Ruf et al. [1953] and McNeill et al.
[1954] have demonstrated that vitamin B 12 (which these investigators named as
'unknown factor isolated from cow dung ') increases cellulose digestion in ruminants.
Cud inoculation in calves increases cellulose digestion. This has been demon-
strated by Pounden et al. [1948, 1949, 1950] and Conrad et al. [1950].
Urea tends to increase cellulose digestion as has been shown by Harris and
Mitchell [1941], Vanderwath [1942], Louw and Vanderwath [1943], Swift et al.
[1947], Briggs et al. [1948] and Burroughs et al. [1951].
Glucose digestion
Fermentation of glucose is also important in the rumen because of its presence
in feeding stuffs. Woodman and Evans [1938] showed that glucose is broken down
by rumen bacteria to pyruvic and lactic acids. Phillipson and McAnally [1942]
obtained lactic acid when glucose, fructose and sucrose were added to diet but not
with lactose, maltose and galactose in a fistula animal. They have also confirmed
that the latter sugars are fermented slower than the former and in the case of the
former sugars the production of lactic acid exceeds its breakdown, while in the latter
case its production is slower than its breakdown.