FR 27. Milk production: responses to high temperature
Milk production, fat and protein contents during last summer are analyzed in the Units of Intensive Milk Production at Rafaela Experimental Station, in Santa Fe, Argentina. Milk production presented an inverse relationship with maximum temperature (P<.01) while percentage of protein decreased as a function of minimum temperature (P<.05). Fat contents also decreased with increasing temperature, the relationship not being statistically significant. When considering a heat wave during December, during which maximum temperature reached 37.9 ºC, these responses were even more significant. Daily milk production per cow after the heat wave was 3.0 L lower than it was before this highly stressing period. It is concluded that temperatures as high as those recorded during the heat wave would not allow for a recovery of milk production; and that protein contents would be more sensitive to the lack of night recovery of the lactating animals.