Animal Science Department


Date of this Version

December 2001


Published for Proceedings, The Range Beef Cow Symposium XVII December 11, 12, and 13, 2001 - Casper, Wyoming.


Reproductive failure in young cows is expensive to many beef operations in the Northern Great Plains. Scientists, nutritionists, and producers have typically placed great effort into heifer development and mature cow management at the expense of two- and three-year-old cows. Meek et al. (1999), working with a ranch in the Nebraska Sandhills, found that the net present value (current animal value accounting for time value of money) of beef females peaked at four years old. Why were bred heifers and pregnant two-year-olds not more valuable than four-year-old cows? Reproductive failure in the young cows did not allow them to stay in the herd to generate revenue over time. In most operations, it is important for cows to produce multiple calves to recover the costs of development.

Managing the nutrition program of young females to meet metabolizable protein (MP) requirements may offer an opportunity to improve reproduction. Supplementation with undegradable intake protein (UIP), also known as bypass or escape protein, may be necessary to meet MP requirements in young females.