Optimizing fiber and protein levels in diet of lactating Murrah buffaloes to ameliorate heat stress: Effect on physiological status and production performance

摘要

The objective of study was to assess the outcome of feeding six total mixed rations (TMR), differing in NDF and protein content, for their synergistic effect on ameliorating heat load of lactating Murrah buffaloes evident through improved physiological and production performance. Thirty six lactating Murrah buffaloes (587 ? 12.3, MY 9 ? 2.2, Parity 2.5 ? 1.5) were arranged in a 3 ? 2 factorial design with three levels of dietary NDF (30, 34.5 and 37% dietary NDF) and two levels of metabolizable protein (MP; 7.0% and 8.4%). Buffaloes were fed either of six dietary treatments: 30%NDF; 7.0% MP (CF1, as recommended), 34.5%NDF; 7.0% MP (MF1), 37%NDF; 7.0% MP (HF1), 30%NDF; 8.4% MP (CF2), 34.5%NDF; 8.4% MP (MF2) and 37%NDF; 8.4% MP (HF2). TMR offered with maize silage and respective concentrate for 90 days feeding trial. Fortnightly feed samples and weekly milk samples collection was done for analyses. Metabolic trial conducted in mid of experiment for estimating nutrient digestibility. Throughout the trial, THI level (79.7?83.8) denoted that buffaloes were exposed to stressful environment. Higher MP in diet reduced pulse rate in buffaloes as compared with lower MP diet. Rectal temperature was lower in Murrah buffaloes fed MF2 diet whereas; minimum breathing rate was recorded for high protein fed group. The MF2 diet increased dry matter intake (kg/d) by 2.7%, milk yield (kg/d) by 8.3% and feed efficiency (milk/DMI) by 7.2% as compared with CF1 group indicating reduced heat load. Increase in protein intake along with improved protein digestibility in MF2 group was recorded. Measured 6%FCM and ECM (kg/d), milk fat (%) and total solid (%) were higher in MF2 treatment group. Results revealed that 34.5% NDF and 8.4% MP have a positive influence on amelioration of heat stress in present experimental conditions.