Heat index based identification of critical heat stress zone for production traits in murrah Buffalo under subtropical climate

• Published in: Biological rhythm research 2023-03, Vol.54 (3), p.334-343
• Main Authors: Behera, Rajalaxmi, Chakravarty, Atish Kumar, Kashyap, Neeraj, Sahu, Adhikari, Deshmukh, Bharti, Dash, Soumya
• Format: Article
• Language: English
• Subjects: critical heat stress zone; daily milk yield; fat; Heat stress; Milk production; murrah; SNF; Temperature effects; THI
• ISSN: 0929-1016; 1744-4179
• DOI: 10.1080/09291016.2023.2171225

Novel study on identification of critical heat stress zone (CHSZ) taking 20 years data was carried out in Indian buffaloes considering the effect of temperature humidity index-THI on milk production and composition traits. More than 3 lakh daily milk yield records (DMY); 9864 records each of monthly test day fat% (MTDF%) and SNF% (MTDSNF%) and meteorological data were collected from ICAR-NDRI and ICAR-CSSRI, Karnal, respectively. THI model [THI = (0.55× T db + 0.2× T dp ) × 1.8 + 32 + 17.5] by National Research Council in 1971 was used for computing THI. The year was classified into: Heat Stress Zone (HSZ) and Non-Heat Stress Zone (NHSZ) based on the trends of rising THI and declining milk production and composition traits. For DMY, NHSZ was 1 st October to 9 th April and HSZ was 10 th April-30 th September. For composition traits, October-March was NHSZ and April-September the HSZ. Within the HSZ regression analysis was conducted to find the zone where maximum drop in traits occur per unit rise in THI. A maximum decline in DMY 92.20 gram was observed during 15 th August-14 th September; identified as CHSZ for DMY. Similarly, maximum drop in MTDF% (b = −0.052) and MTDSNF% (b = −0.0114) observed during July-August, considered as CHSZ.