Journal of Animal Research: v.5 n.1, p. 47-52. April. 2015
DOI Number: 10.5958/2277-940X.2015.00008.X
Evaluation of Sorghum Stover Based Complete Rations with Different Roughage to
Concentrate Ratio for Efficient Microbial Biomass Production by
Using In Vitro Gas Production Technique
Y. Ramana Reddy 1 , N. Nalini Kumari 2 , T. Monika 2 , M. Pavani 2 and K. Sridhar 2 *
1 International Livestock Research Institute, C/o ICRISAT, Patancheru, Hyderabad, INDIA.
2 Department of Animal Nutrition, College of Veterinary Science, S. V. Veterinary University, Rajendranagar, Hyderabad, INDIA
*Corresponding author: K Sridhar; Email:
Received: 23 January, 2015
Accepted: 26 February, 2015
An in vitro study was conducted to evaluate the optimum roughage to concentrate ratio in complete rations using sorghum
stover (SS) as a roughage source since it is a main feed resource for urban and peri-urban dairies. Eight complete rations were
prepared with roughage (R) to concentrate (C) ratio of 100R:0C to 30R:70C. In vitro gas production (ml) at 24 h incubation, in
vitro organic matter digestibility and metabolizable energy, truly digestible organic matter and ammonia nitrogen production
were increased linearly (P<0.01) as the proportion of concentrate was increased in the ration. Significantly higher (P<0.01)
total volatile fatty acid concentration was observed in 50R:50C, 40R:60C and 30R:70C compared to other rations. Significantly
(P<0.01) highest partitioning factor, microbial biomass production and efficiency of microbial biomass production were
recorded at 60R:40C ratio followed by 50R:50C. Therefore, the present study suggested that SS can be included in complete
rations for ruminants at the level of 60 per cent for economic milk and meat production.
Keywords: Sorghum Stover, Complete ration, In vitro gas technique, Roughage to concentrate ratio.
Crop residues left after harvesting grain from cereal
important to remember here that the ratio of crop residues
crops are the main source of roughage for feeding of
and concentrate in the ruminant diets greatly influences
ruminants in arid and semi-arid regions of India. Currently
the economics and efficiency of utilization of dietary
they constitute more than 40 per cent of dry matter in
nutrients. The supplementation of concentrate mixture
Indian ruminant diets (Rao et al., 2003). More recently
is aimed at maximizing the ruminal microbial protein
Ramachandra et al. (2005) estimated that crop residues
(MP) production. High MP production decreases the need
will provide more than 70% of the feed resources for the
for supplementing rumen undegradable feed protein by
Indian ruminant population by the year 2020. However,
proportionally increasing carbon and nitrogen fixation into
crop residues are low in protein, energy and other
microbial cells there by reducing fermentative carbon (C)
important micronutrients essential for animal production.
losses in CO 2 and CH 4 and nitrogen (N) losses in the urine
Therefore incorporation of concentrate ingredients in
(Blümmel et al., 1999).
crop residue based diets is recommended to overcome
nutrient deficiencies and optimize the efficiency of crop
Sorghum is an important staple food crop in semi-arid
residues utilization in ruminants for growth, gestation
tropical areas and its stover is the main feed resource
and milk production. The concept of complete diet
for urban and peri-urban dairies. Hence, in the present
was promoted by different research workers in India
study, sorghum stover was used as roughage source in the
where both crop residues and concentrate ingredients
complete diet and the optimum roughage to concentrate
were processed and blended together before feeding for
ratio was determined by using in-vitro gas technique.
efficient utilization of crop residues by ruminants. It is
In-vitro gas measuring technique is one of the easy and