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

Abstract

Global warming has been increasing heat stress threat in animals, which can be monitored via the Temperature Humidity Index (THI). The present study describes the THI pattern and the relationship between THI and the production performances of dairy cows in a selected area of Bangladesh. The THI value was calculated using weather station data gathered over 35 years. Based on the THI pattern, January and June were identified as the coolest and hottest months, respectively. Consequently, the production performances of 10 crossbred cows with homogenous characteristics were monitored every January and June for a 5-year period. The average THIMEAN was found to be 17% higher in June when compared to January; with this increment of THIMEAN, average milk production was decreased by 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 a negative correlation. However, ash content increased by 15.3%, which indicates a positive correlation. In addition, multiple regression analysis revealed that, with each point increase in THIMEAN and rectal temperature, there was a decrease in milk yield of 0.04 and 1.17 kg ECM, respectively. In contrary, each point increase in THIMEAN resulted in 0.059 °C increase of rectal temperature. Taken together, THIMEAN calculated using meteorological station data has a distinct relationship with the production performances of lactating crossbred dairy cows.

Analysis of the climatic trends and heat stress periods for ruminants rearing in Bangladesh

“…Based on the HS levels established for ruminants ( Lallo et al, 2018 ), the THI ruminant values showed thermal stress level, even in the winter season ( Fig. 3 ), which aligns with findings from prior research ( Lallo et al, 2018 ; Hossain et al, 2022 ; Al Reyad et al, 2016 ; Chanda et al, 2018 ). A study ( Lallo et al, 2018 ) found that ruminants THI increased more rapidly at Montego Bay compared to the other two areas after the cooler winter season.…”

“…One case study found that highest average THI value in dairy cow was reported in the month of July in a specific region of Bangladesh ( Al Reyad et al, 2016 ). Other studies in Bangladesh examined the THI of dairy farms discovered that the highest THI was in the month of May ( Chanda et al, 2018 ) and June ( Hossain et al, 2022 ). Our study revealed that the west central area had the greatest THI ruminant level, with June becoming the hottest month.…”

“…T represents the dry-bulb temperature, while Td represents the dew point temperature, both measured in degrees Celsius. The dew point temperature (Td) was estimated using the dry-bulb temperature and relative humidity calculation from Hossain et al (2022) . …”

Assessment of the temperature and humidity index (THI) to facilitate the establishment of a ruminant rearing system in Bangladesh

“…Temperature and humidity have a significant impact on livestock farming and are major contributors to global warming. Due to global climate change, several challenges are being encountered in different locations of Bangladesh (Hossain et al, 2022). Different indices are employed to assess the level of heat stress experienced by livestock.…”