Invited Review: Genes Involved in the Bovine Heat Stress Response¹

Relationship between infrared coat surface temperature and evaporative heat loss (EVHL) in Holstein dairy cows. Open circles and regression correlation (R²=0.4348) denote EVHL below 35°C. Closed circles and regression correlation (R²=0.0358) denote EVHL above 35°C. Slopes of 2 regressions differ, P<0.001.

Expression of heat shock protein (HSP)-70 in primary bovine mammary epithelial cells cultured for 8h at 42°C. Both prostaglandin A₁ (PGA₁) and prostaglandin E₁ (PGE₁) are 24μM solutions in control media, which is the same as the growth media for d 1 to 8. Expression (y-axis) is relative to control media at 0h and 37°C. Addition of prostaglandins and exposure to temperature began after 8 d in culture at 37°C. Results represent mean of 3 experiments. Different letters indicate significant differences in treatments, P=0.002.

Phase contrast (5×) images of bovine mammary epithelial cells cultured at 37°C or 42°C in media containing prostaglandin A₁ (PGA₁) or saline (Control) for 20h.