Crossbreeding Dairy Cattle. II. Weights and Body Measurements of Purebred Holstein and Guernsey Females and Their Reciprocal Crossbreds

Body weights and five linear body measurements of reciprocal crossbred and purebred Holstein and Guernsey females were analyzed and compared. Weights and measurements were taken at Means of the crossbreds were larger than those of the purebreds at all ages for all variables. Effects of crossbreeding were significant in 21 of the 30 cases at the ages of 3, 6, 12, 18, and 24 months, but were significant in none of the 18 cases at 30, 36, and 48 months. Effects of crossbreeding decreased linearly as age increased. The percentage increase for weight ranged from 7.1% at birth to 1.5% at 48 months. Percentage increases were greater for weight than for body measurements and were larger for the measures of fleshiness, chest depth, heart girth, and paunch girth, than for the skeletal measurements, wither height, and body length. At all ages, calves out of Holstein dams were approximately 20% heavier than those out of Guernsey dams, whereas calves by Holstein sires were approximately 9% heavier than those by Guernsey sires. The difference between the magnitude of the effects of breed of dam and breed of sire did not change as age increased and was likely a result of prenatal maternal effects.