Table 4.

Summary statistics for environmental THI, physiological performance, and milk yield in April (non-heat stress) and July (heat stress)

Index at test day	Non-heat stress (April)	Heat stress (July)
Rectal temperature	38.50 ± 0.19	39.3 ± 0.67
Respiration rate score	37.67 ± 6.37	95.17 ± 16.30
Drooling score	1 ± 0.00	2 ± 0.82
Milk yield	41.48 ± 3.52	35.25 ± 3.71
THI	61.37 ± 8.18	81.62 ± 3.89