title: Evaluation of optimum roughage to concentrate ratio in maize stover based complete rations for efficient microbial biomass production using in vitro gas production technique.
abstract: OBJECTIVE
  A study was undertaken to evaluate the optimum roughage to concentrate ratio in maize stover (MS) based complete diets for efficient microbial biomass production (EMBP) using in vitro gas production technique.
  
  
  METHODS
  MS based complete diets with roughage to concentrate ratio of 100:0, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, and 30:70 were formulated, and 200 mg of oven-dried sample was incubated in water bath at 39°C along with media (rumen liquor [RL] - buffer) in in vitro gas syringes to evaluate the gas production. The gas produced was recorded at 8 and 24 h of incubation. In vitro organic matter digestibility (IVOMD), metabolizable energy (ME), truly digestible organic matter (TDOM), partitioning factor (PF), and EMBP were calculated using appropriate formulae. Ammonia nitrogen and total volatile fatty acids (TVFAs) production were analyzed in RL fluid-media mixture after 24 h of incubation.
  
  
  RESULTS
  In vitro gas production (ml) at 24 h incubation, IVOMD, ME, TDOM, TVFA concentration, and ammonia nitrogen production were increased (p<0.01) in proportion to the increase in the level of concentrate in the diet. Significantly (p<0.01) higher PF and EMBP was noticed in total mixed ration with roughage to concentrate ratio of 60:40 and 50:50 followed by 70:30 and 40:60.
  
  
  CONCLUSIONS
  Based on the results, it was concluded that the MS can be included in complete rations for ruminants at the level of 50-60% for better microbial biomass synthesis which in turn influences the performance of growing sheep.
authors.affiliation: Department of Animal Nutrition, College of Veterinary Science, Kadapa - 516 360, Andhra Pradesh, India.
authors.forename: Y Ramana
authors.initials: YR
authors.lastname: Reddy
authors.affiliation: Department of Animal Nutrition, College of Veterinary Science, Hyderabad - 500 030, Telangana, India.
authors.forename: N Nalini
authors.initials: NN
authors.lastname: Kumari
authors.affiliation: Department of Animal Nutrition, College of Veterinary Science, Hyderabad - 500 030, Telangana, India.
authors.forename: T
authors.initials: T
authors.lastname: Monika
authors.affiliation: Department of Animal Nutrition, College of Veterinary Science, Hyderabad - 500 030, Telangana, India.
authors.forename: K
authors.initials: K
authors.lastname: Sridhar
keywords: complete ration; in vitro gas technique; maize stover; roughage to concentrate ratio