In July 2010, the following daily temperatures were measured in the farm of VÚŽV, v.v.i. at Netluky on average: maximum 28,5±5,4oC, minimum 15,3±3,0oC in July 2010; 15 days were tropical, with temperatures above 30oC. The goal of the work was to ascertain how dairy cows respond by milk production to such high temperatures and how the temperatures influence the aerobic stability of corn silage. The lowest yield (24,5 l/cow/day) was registered on the day when the outside temperature was the highest (36,7 oC). When it got colder to about 20oC after three weeks, the milk yield increased from 25,8 to 27,2 litres per milk cow and day within four days. The average daily milk yield of 227 dairy cows amounted to 25,9±0,7 l/cow/day in that month. The measurement of the temperatures of the surface layers of the silages demonstrated negative influence of high temperatures on the aerobic stability of silages. The silage samples taken from a depth of 0 to 15 cm after 24 hours of aeration (access of air) had average temperatures of 56,3±3,4oC, from a depth of 16 to 30 cm 42,0±2,1oC, from a depth of 31 to 45 cm 29,8±4,1oC, from a depth of 46 to 60 cm 25,5±0,7oC.