Live animal evaluation takes into consideration any subjective measurements
that help describe an animal. Some common measurements of cattle include
backfat, pelvic area, scrotal circumference, height at the shoulder, height
at the hip, and length of body.
In recent years, height measurements have become a descriptive supplement
to many herd testing programs. Linear measurements for height have added
another dimension to evaluating the lean-fat ratio of an individual animal.
How much emphasis breeders should place on linear measurement should depend
on their goals relative to type of cattle desired. A linear measurement
should never be interpreted as a replacement for the weight of an animal
at a given age.
Frame Score
Frame score is a convenient way of describing the skeletal size of
cattle. The Beef Improvement Federation Guidelines (1996) define frame
score as follows:
Frame score is a score based on subjective evaluation of height or actual measurement of hip height. This score is related to harvest weights at which cattle should attain a given quality grade or attain a given amount of fat thickness.
Frame score of an animal is determined by mathematical equations that use age and height as variables. No one frame size for an animal will be best for all feed resources, breeding systems, and feed costs. Reproductive efficiency and projected market weight will determine the optimum frame size range within a given set of feed resources, breeding systems, and production costs.
With adequate height growth curves, most animals should maintain the same frame score throughout their life while their actual height increases with age. Frame size can be influenced by nutritional management. Frame score is easily determined if age and height in inches are available (Tables 1 through 4). Estimates of cattle heights and corresponding frame scores are given for bulls and heifers (5 to 21 months), as well as mature bulls and cows (24 to 48 months). Bull height estimates may be used to approximate steer frame values.
The recommended point for linear measurement of hip height is over the hooks and hip bones (Figure 1).Hip heights should not be used as a replacement for other performance data. Although no one frame size is best for all producers, hip heights or frame scores do provide supplemental information for the breeder and the buyer. Hip heights should be measured in inches directly over the hooks (hip bones) with the animal standing on a level surface. To make accurate comparisons, age should be considered when measuring hip height. For additional information regarding hip height adjustments on postweaning bulls, see OSU Extension Facts F-3002 Postweaning Evaluation Programs for Beef Bulls.
Frame score tables are recommended by the Beef Improvement Federation. Individual breed associations have developed their own frame score charts. A producer who is interested in one breed should contact that particular breed association.
Reference:
Beef Improvement Federation (BIF) Guidelines. 1996. Seventh
edition. pp. 17-20.
Original Publication was written by Charles McPeake.
From:
http://www.ansi.okstate.edu/exten/beef/f-3271/f-3271.html