Assessing thermal neutral zones in Sri Lanka for ten different dairy cattle breeds and crosses: An approach using temperature humidity index (THI)

The magnitude of heat stress in dairy cattle is assessed using temperature humidity index (THI) widely the world. present study was conducted to assess appropriateness incorporating THI recommending breeds different areas Sri Lanka. considered 10 genotypes commonly reared for milk production country.  Daily values were computed by employing a thermal model, = Tdb - [0.55 (0.55 × RH/100)] (Tdb 58) data collected from 26 meteorological stations 2005-2014. regions and threshold used produce maps. Among crosses, Jersey crossbreds, except Friesian cross, showed high coping ability with comparatively capacity. Local not affected within range observed country. based recommendation distribution could be made identifying variation genotype minimizing vulnerability climate change. Therefore, costly management interventions needed mitigate related low productivity under smallholder systems abated. Key words: Climate change, breeds, stress.