PhD

An investigation was carried out to determine the ruminal protein
degradability of groundnut cake, gingelly cake, rubber seed cake, coconut
cake yellow maize, wheat bran and guinea grass and to determine the
correlation between their degradability in rumen and solubility in mineral
solvents and autoclaved rumen fluid. The effect of heat treatment and the
formaldehyde treatment on the protein degradability of groundnut cake,
gingelly cake and rubber seed cake was also studied. The effect of different
levels of degradable proteins in the ration on the rumen fermentation
pattern in cows and on growth rate and digestibility of nutrients in calves
were also studied.
The degradability of proteins of the feed stuffs in the rumen were
estimated employing the nylon bag technique using five fistulated cows.
The effective protein degradability was determined using the formula P = a
+ bc where k is the
c+k
fractional outflow rate from the rumen and a, b and c are the constants of
the exponential equation p = a + b (1 – e–ct). The effective protein
degradability values of groundnut cake, gingelly cake, rubber seed cake,
coconut cake, yellow maize, wheat bran and guinea grass at a rumen
outflow rate of 0.05/h were 66.76, 85.12, 68.12, 68.61, 19.09, 22.83, 77.02
and 41.50 per cent respectively. Among the oil cakes coconut cake was least
degradable in the rumen and was found to be a good source of bypass
protein for ruminants. Heat treatment (1500C for 2 hours) reduced the
protein degradability of groundnut cake, gingelly cake and rubber seed
cake by 83.18, 76.80 and 70.10 per cent respectively at an outflow rate of
0.05/h and the formaldehyde
treatment (1 g/100g CP) reduced the protein degradability of these cakes by
55.98, 45.45 and 44.33 per cent respectively at the same outflow rate.
Significant correlations were observed between protein degradability of
feed stuffs in the rumen and their solubility in 0.15 M sodium chloride (r =
0.79), McDoughal’s artificial saliva (r = 0.74) and autoclaved rumen fluid (r
= 0.81). No correlation could be observed between the protein degradability
in the rumen and the solubility in Burroughs mineral solution. A
significantly high correlation (r = 0.91) was also observed between protein
degradability in the rumen and the percentage of protein loss from control
bags due to washing.
Rumen pH and ammonia nitrogen concentration were significantly
higher in the animals receiving rations with higher levels (76.90%) of
degradable proteins. The total volatile fatty acid concentration was
significantly high in the animals receiving rations with lower levels
(45.30%) of degradable protein.
The effect of three levels (44.50, 60.50 and 71.30 per cent) of degradable
proteins in the ration on growth and digestibility of nutrients was studied
using 18 growing calves divided into three groups. The final body weight
and the daily weight gain of the calves receiving the lower levels (44.50%)
of degradable protein in the ration were significantly high as compared
with those obtained in the case of calves receiving higher levels (60.50 and
71.30%) of degradable protein. The drymatter intake and the digestibility
of nutrients of the rations were not influenced by the level of degradable
proteins in the ration. The optimum level of degradable protein sufficient
to support growth was found to be 45 per cent.