Relationship between Preweaning Nutritional Management and the Growth and Development of Angus and Hereford Females

A Total of 206 Angus and Hereford females were used in four trials to determine the effects of three preweaning planes of nutrition imposed by (1) weaning at 140 days, (2) weaning at 240 days and (3) creep-feeding and weaning at 240 days. At 240 days of age, 140-day weaned, 240-day weaned and creep-fed females weighed 175.7, 206.5 and 226.0 kg, respectively. After weaning, all females were treated alike under range conditions. Weights and body measurements, actual and photographic, were taken at 140 days, 240 days, 1.0 year and 6-month intervals thereafter to 4.5 years. Body weight, length of body, height at hooks and withers, and circumference of heart girth were significantly (P<.05) affected by treatment to 1.5 years. The creep-fed females gained the least and the 140-day weaned females the most in structural size between 240 days and 2.0 years of age. The creep-fed females lost more weight and condition during their first pregnancy (which coincided with their first winter) than did the other treatments (which remained rather constant). The creep-fed group also showed a greater decrease in rate of skeletal growth than the other treatments during this period. No significant difference (P>.10) for any measurement of height between 240-day weaned and creep-fed groups was ever noted, although a significant (P<.05) difference between extreme treatments was apparent through 1.5 years of age. The 140-day weaned group tended to remain smaller for all variables studied, but differences after 1.5 years of age were small.