Seasonal variation in body mass index, cardinal physiological variables and serum thyroid hormones profiles in relation to susceptibility to thermal stress in goat kids

•Cold stress susceptible goats had significantly lower rectal temperature, but higher pulse rate than cold stress tolerant goats.•Heat stress susceptible goats had markedly lower T3 than the heat stress tolerant goats.•Rectal temperature, pulse rate and T3 had greater influence on the susceptibility of kids to thermal stress.•Lower T3 was recorded during the hot-dry season compared to other seasons, whereas T4 remained unaffected.