Effect of induced Fasciola gigantica infection during pre-patency on the performance of buffalo calves fed on different percentage of protein.

Thirty growing Murrah buffalo calves (8-12 months of age, 109.85 ± 2.43) were reared in parasite free conditions and randomly divided into three equal groups as per CRD. They were fed on iso-caloric (2.01 ME Mcal/Kg diet) diets containing standard protein (SP) diet at 100 %, 90 % of SP (medium protein, MP) and 80 % of SP (low protein, LP) of the protein requirements (Kearl 1982). After 21 days of feeding, each group was further subdivided into two sub-groups (A & B). Animals in sub-groups 'A' served as non-infected control, while in sub group 'B' were orally infected with Fasciola gigantica metacercarie (mc; 1,000 each). A metabolic trial of 40 days post infection was carried out in control and parasitized animals. Intake of digestible dry matter, organic matter and acid detergent fibre (ADF) was significantly higher (P < 0.05) in SP group compared to LP group. The digestibility of crude protein (CP) and ADF was significantly higher in SP group compared to MP and LP groups. The digestible crude protein (DCP) and total digestible nutrients (TDN) intakes (g/kgW(0.75)) were also significantly (P < 0.001) higher in SP than MP and LP groups. However, DCP intake was significantly (P < 0.001) lower in infected subgroups compared to control subgroups. Intake and balance (g/d) of nitrogen, calcium and phosphorus were significantly (P < 0.01) higher in SP than MP and LP groups. The average daily gain of buffalo calves fed on SP Uninfected (SPU), SP Infected (SPI), MPU, MPI and LPU, LPI groups was 333, 178, 356, 144, 222 and 144 g and was significantly (P < 0.01) lower in animals fed LP ration. The feed conversion ratio (FCR) was also significantly (P < 0.01) higher in infected sub-groups as compared to respective control groups. The results showed that a SP diet substantially improved the overall performance of buffalo calves in control and infected groups and reduced adverse effect of F. gigantica infection.