EFFECTS OF CLIMATE CHANGE ON MILK YIELD AND MILK COMPOSITION IN THAI CROSSBRED HOLSTEIN COWS

The purpose of this research was to study effects of climate changes on milk yield and milk composition of Holstein crossbred . This study uses data recording total milk production per farm each day and milk composition (from 2013-2017): fat percentage (% Fat), protein percentage (% Pro), solid not fat percentage (% SNF) and total solid percentage (% TS) from 79 farmers in Mahasarakham Province, Thailand. The temperature and humidity data were obtained from records of meteorological center. Using temperature and relative humidity for calculate temperature humidity index (THI). The effects of THI on milk yield and milk composition were assessed by procedure REG using SAS. The study indicated that, the weather was hot and humid. The temperature ranged from 20.88 - 33.01 degrees C. and average humidity was 72.59%. The highest THI (82.07) was in May. The relationship between THI and milk yield was negatively related. The slope value was -0.099, it meaning that when the THI value increased by 1 unit the milk yield decreased by 0.099 kg / cow / day. The THI group for effect of THI on milk yield and milk composition was set 4 groups (THI 1 = THI <= 70,THI 2 = 74 <= THI<70,THI 3=78 <= THI<74,=THI 4 =THI>78). The highest THI effect on low milk yield. In contrast, low THI (THI 1 and THI 2) effect on high milk yields. The climate change, temperature and humidity increase effects on milk production of dairy cows to decrease.