Productivity as Two-Year-Olds of Angus-Holstein Crossbreds Compared to Angus Heifers under Range Conditions

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Abstract
The productivity as 2-year-olds of 31 Angus-Holstein crossbred heifers was compared to 41 grade Angus heifers under tall grass range conditions. The period studied was from breeding as yearling through weaning of the first calf. Characteristics evaluated were milk production, calf growth, reproduction performance, and cow weight changes. Effect of calving date on early milk production was also examined. All heifers were exposed to yearling Angus bulls during a 90-day breeding season. The heifers were on native grass at all times which was supplemented with hay and protein cubes during the winter. Daily milk production was estimated at biweekly and monthly intervals by the calf nursing method. Calf weights and cow weights and condition scores were taken at each milk test. In the fall, calves were weaned at an average age of 205 days, and the cows were pregnancy checked to determine conception rate. The crossbred cows produced more milk at all test periods. Milk yield during early lactation varied according to calving date, especially in the crossbreds. The 200 day adjusted total milk production for the crossbred cows was higher (P<.01) than the Angus cows by 341 kg (1136 vs. 795 kg). The 205 day adjusted weaning weights of the crossbred calves were heavier (P<.05) than the Angus calves by 20.3 and 34.5 kg for the steers and heifers, respectively. However, the most important result was that only 13% of the crossbred cows that nursed calves rebred compared to 63% of the Angus cows. This difference was probably due to the low nutritional level on the range. The crossbreds lost 25.5 kg during the lactation period compared to 3.2 kg (P<.01) for the Angus. These results indicate that crossbreds are capable of producing more milk and heavier weaning calves under range conditions but probably need a higher level of nutrition to rebreed and maintain body weight. Copyright © 1971. American Society of Animal Science . Copyright 1971 by American Society of Animal Science.

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