Relationship of Meteorological Data with Heat Stress Effect on Dairy Cows of Smallholder Farmers

Global warming has been increasing heat stress threat in animals which can be monitored by Temperature Humidity Index (THI). The present study describes the relationship of THI, calculated using 35 years period weather station data, and production performances of dairy cattle in a se-lected area of Bangladesh. The month January and June were identified as the coolest and hottest, respectively. Based on this outcome, every year in the month of January and June production performances of 10 crossbred cows with homogenous characteristics were monitored for a period of 5 years. The average THIMEAN value was found 17% higher in June as compared to January, and with this increment of THIMEAN average milk production was decreased 24.4% (p<0.05). The milk fat and protein content were also reduced (p<0.05) by 14.5 and 15.2%, respectively suggesting negative correlation as like as milk production. However, ash content was increased 15.3% that indicates a positive correlation. In addition, multiple regression analysis revealed each point increase in THIMEAN and rectal temperature, there was a decrease in milk yield 0.04 and 1.17 kg ECM, respectively. In contrary, each point increase in THIMEAN resulted 0.059 C increase of rectal temperature. Taken together, THIMEAN value calculated using metrological station data has distinct relationship with the production performances of lactating crossbred dairy cows.