Body weight and seven body dimensions measuring the length, height, width and depth were taken at birth and every 180 days up to 720 days of age on 49 pure Canadian, 49 first cross of 1/2 Brown Swiss 1/2 Canadian, and 30 backcross of 1/4 Brown Swiss 3/4 Canadian heifers. The animals were raised up to 180 days of age at the Deschambault Station, then half the pure Canadian and the first cross were transferred to the La Pocatière Station. At birth, the pure Canadian calves weighed 29.2 kg and were lighter than the first and backcrosses by 6.9 kg (24%) and 4.8 kg (16%), respectively. The two crosses exceeded the pure Canadian in all the dimensions, the differences being significant in height at shoulder and width at rumps. At 360 days of age the two crosses were about 6% heavier and 4% higher at shoulder than the pure Canadian. With the exception of body length after 1 yr of age in which the backcross was slightly inferior to the pure Canadian, the two crosses were generally larger than the pure Canadian, with the backcross being intermediate between the first cross and the pure Canadian. The effects of season of birth and age of dam were found to be non-significant on most of the traits studied in this experiment.
Heat Stress Elicits Different Responses in Peripheral Blood Mononuclear Cells from Brown Swiss and Holstein Cows