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Evaluation of live animals takes into consideration any measurements or subjective evaluations that help describe an animal. For example, evaluation involves physical examination of bulls to include penis, rectal examination, and scrotum (including scrotal circumference--see 2. Reproduction).
Some other common measurements of cattle include: backfat, pelvic size (see 2. Reproduction), height at the shoulder, height at the hip, and length of body.
In recent years, measurements for height have become a descriptive supplement to many herd testing programs. Adjusted weights and weight ratios accompanied by linear measurements for height have added another dimension to evaluating the fat-lean ratio of an individual animal in a performance program.
Linear measurements are objective. They serve as supplemental information for comprehensive performance testing. How much emphasis breeders should place on linear measurement information should depend on their goals relative to shape and growth patterns, the extent to which certain shape relationships may be important to them, and any advantage these shape relationships give them in marketing beef cattle.
A linear measurement should never be interpreted as a replacement for the weight of an animal at a given age. Instead, linear measurements should be used with growth information as a supplement for selection. No one frame size for an animal will be best for all feed resources, breeding systems, and feed costs. Reproductive efficiency and market weight will determine the optimum frame size range within a given set of feed resources, breeding systems, and production costs.
5.1: Frame Score
Frame score is a convenient way of describing the skeletal size of cattle. With adequate height growth curves, most animals should maintain the same frame score throughout their life while their actual height increases with age. This allows one frame score value to be used regardless of when the animal was evaluated (within the range of available data). Environmental factors can alter the growth rate from an animal’s genetic capability. Nutrition level is a major factor. Cattle fed less than adequate nutrition will grow slower than the tables indicate while cattle fed extremely high levels will grow faster.
The recommended point for linear measurement for height is to a point directly over the hooks (Fig. 5.1). This measurement is adjusted to relatively logical production end points at 205 days and 365 days (within the BIF ranges currently used for adjusted weights). It is recommended that the actual hip height and adjusted hip height be printed in the national cattle evaluation (see Sire Evaluation section) but that no height ratio be calculated.
Adequate height growth curves must take into consideration the differences in growth rate between small and large frame cattle. The accompanying tables and equations are currently the best estimates of cattle height and growth rate.
Figure 5.1.--Height Measurement
Table 5.1--Bull Hip Height (inches) Frame Score
Age in
Months |
Frame Score |
| 1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
| 5 |
33.5 | 35.5 | 37.5 | 39.5 | 41.6 | 43.6 | 45.6 | 47.7 | 49.7 |
| 6 |
34.8 | 36.8 | 38.8 | 40.8 | 42.9 | 44.9 | 46.9 | 48.9 | 51.0 |
| 7 |
36.0 | 38.0 | 40.0 | 42.1 | 44.1 | 46.1 | 48.1 | 50.1 | 52.2 |
| 8 |
37.2 | 39.2 | 41.2 | 43.2 | 45.2 | 47.2 | 49.3 | 51.3 | 53.3 |
| 9 |
38.2 | 40.2 | 42.3 | 44.3 | 46.3 | 48.3 | 50.3 | 52.3 | 54.3 |
| 10 |
39.2 | 41.2 | 43.3 | 45.3 | 47.3 | 49.3 | 51.3 | 53.3 | 55.3 |
| 11 |
40.2 | 42.2 | 44.2 | 46.2 | 48.2 | 50.2 | 52.2 | 54.2 | 56.2 |
| 12 |
41.0 | 43.0 | 45.0 | 47.0 | 49.0 | 51.0 | 53.0 | 55.0 | 57.0 |
| 13 |
41.8 | 43.8 | 45.8 | 47.8 | 49.8 | 51.8 | 53.8 | 55.8 | 57.7 |
| 14 |
42.5 | 44.5 | 46.5 | 48.5 | 50.4 | 52.4 | 54.4 | 56.4 | 58.4 |
| 15 |
43.1 | 45.1 | 47.1 | 49.1 | 51.1 | 53.0 | 55.0 | 57.0 | 59.0 |
| 16 |
43.6 | 45.6 | 47.6 | 49.6 | 51.6 | 53.6 | 55.6 | 57.5 | 59.5 |
| 17 |
44.1 | 46.1 | 48.1 | 50.1 | 52.0 | 54.0 | 56.0 | 58.0 | 60.0 |
| 18 |
44.5 | 46.5 | 48.5 | 50.5 | 52.4 | 54.4 | 56.4 | 58.4 | 60.3 |
| 19 |
44.9 | 46.8 | 48.8 | 50.8 | 52.7 | 54.7 | 56.7 | 58.7 | 60.6 |
| 20 |
45.1 | 47.1 | 49.1 | 51.0 | 53.0 | 55.0 | 56.9 | 58.9 | 60.9 |
| 21 |
45.3 | 47.3 | 49.2 | 51.2 | 53.2 | 55.1 | 57.1 | 59.1 | 61.0 |
|
Frame Score = -11.548 + 0.4878 (Ht) - 0.0289 (Days of Age) + 0.00001947(Days of Age)2 + 0.0000334 (Ht) (Days of Age)
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Table 5.2--Heifer Hip Height (inches) Frame Score
Age in
Months |
Frame Score |
| 1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
| 5 |
33.1 | 35.1 | 37.2 | 39.3 | 41.3 | 43.4 | 45.5 | 47.5 | 49.6 |
| 6 |
34.1 | 36.2 | 38.2 | 40.3 | 42.3 | 44.4 | 46.5 | 48.5 | 50.6 |
| 7 |
35.1 | 37.1 | 39.2 | 41.2 | 43.3 | 45.3 | 47.4 | 49.4 | 51.5 |
| 8 |
36.0 | 38.0 | 40.1 | 42.1 | 44.1 | 46.2 | 48.2 | 50.2 | 52.3 |
| 9 |
36.8 | 38.9 | 40.9 | 42.9 | 44.9 | 47.0 | 49.0 | 51.0 | 53.0 |
| 10 |
37.6 | 39.6 | 41.6 | 43.7 | 45.7 | 47.7 | 49.7 | 51.7 | 53.8 |
| 11 |
38.3 | 40.3 | 42.3 | 44.3 | 46.4 | 48.4 | 50.4 | 52.4 | 54.4 |
| 12 |
39.0 | 41.0 | 43.0 | 45.0 | 47.0 | 49.0 | 51.0 | 53.0 | 55.0 |
| 13 |
39.6 | 41.6 | 43.6 | 45.5 | 47.5 | 49.5 | 51.5 | 53.5 | 55.5 |
| 14 |
40.1 | 42.1 | 44.1 | 46.1 | 48.0 | 50.0 | 52.0 | 54.0 | 56.0 |
| 15 |
40.6 | 42.6 | 44.5 | 46.5 | 48.5 | 50.5 | 52.4 | 54.4 | 56.47 |
| 16 |
41.0 | 43.0 | 44.9 | 46.9 | 48.9 | 50.8 | 52.8 | 54.8 | 56.7 |
| 17 |
41.4 | 43.3 | 45.3 | 47.2 | 49.2 | 51.1 | 53.1 | 55.1 | 57.0 |
| 18 |
41.7 | 43.6 | 45.6 | 47.5 | 49.5 | 51.4 | 53.4 | 55.3 | 57.3 |
| 19 |
41.9 | 43.9 | 45.8 | 47.7 | 49.7 | 51.6 | 53.6 | 55.5 | 57.4 |
| 20 |
42..1 | 44.1 | 46.0 | 47.9 | 49.8 | 51.8 | 53.7 | 55.6 | 57.6 |
| 21 |
42.3 | 44.2 | 46.1 | 48.0 | 50.0 | 51.9 | 53.8 | 55.7 | 57.7 |
|
Frame Score = -11.7086 + 0.4723 (Ht) - 0.0239 (Days of Age) + 0.0000146 (Days of Age)2 + 0.0000759 (Ht) (Days of Age)
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5.1.1: Adjusted Weaning Heights. The sex adjustment factor for heights at weaning are:
|
Bulls: | 0.033 inch |
| Heifers: | 0.025 inch
|
Age-of-dam adjustment factors for height at weaning are:
Age of Dam
(years) |
Bulls
(weaning weight) |
Heifers
(weaning weight) |
|
| 2 and 13 or older |
1.02 |
1.02 |
| 3 and 12 |
1.015 |
1.015 |
4 and 11 or older |
1.01 |
1.01 |
5 through 10 |
-----(No Adjustment)----- |
|
To adjust heights to 205 days for sex; (1) multiply the number of days under 205 by 0.033 for bulls or 0.025 for heifers, and ~ to the actual height; or (2) multiply the number of days over 205 by 0.033 for bulls or 0.025 for heifers and subtract the result from the actual height. To adjust for age of dam, multiply the adjusted height for sex by the age-of-dam factor.
Example:(heifer)
Actual data: Born January 1, 1979; birth weight 70 pounds; weaned July 21, 1979; weight 470 pounds; height 38 inches; 201 days old; dam 3 years old; adjusted 205-day weight is 496 pounds.
|
205 days - 201 days = 4 days
38 inches + (4 * 0.025) = 38.1 inches * 1.015 = 38.67 inches = 205-day height adjusted for age of dam and sex of calf.
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5.1.2: Adjusted Postweaning Heights.
1. Bulls -- Daily adjustment may be made as follows:
- Adjustment for bulls under 365 days:
Actual height + (Number of days under 365 x 0.033) = Adjusted height.
- Adjustment for bulls over 365 days:
Actual height - (Number of days over 365 x 0.025)
2. Heifers -- Remember that the great variation in the nutritional levels of rations which heifers are fed between weaning and 1 year old can vary their growth rate slightly. The following daily adjustments, however, are fairly accurate for all heifers fed to gain in a range from 0.75 to 2.0 pounds per day.
- Adjustment for heifers under 365 days:
Actual height + (Number of days under 365 x 0.025) = Adjusted height.
- Adjustment for heifers over 365 days:
Actual height - (Number of days over 365 x 0.025)
Example:(bull)
Actual data: 359 days old; height 49.5 inches; adjusted 365-day weight is 1,050 pounds.
365 days - 359 days = 6 days
49.5 inches + (6 * 0.033) = 49.7 inches = Adjusted postweaning height.
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