Selecting Beef Cattle
OVERVIEW
INSTRUCTOR:
UNIT: Discussing Animal Selection, Reproduction, Breeding, and Genetics
LESSON: Selecting Beef Cattle
IMS REFERENCE: #8399
TOPIC NOTES
SELECTING BEEF CATTLE
The purpose of this topic is to introduce methods of beef cattle selection that are currently
utilized by many successful producers in today’s beef industry. While there are various
types of beef cattle producers (slaughter, stocker, cow/calf, and purebred breeders), this
topic deals mainly with the commercial cow/calf producer and the purebred breeder of
cattle. Numerous factors are involved in the selection of beef cattle. Knowledge of these
selection practices and how to properly apply them can help improve a producer’s herd
genetics and economics.
METHODS OF SELECTION
The methods of beef cattle selection that are used must support the goals of the
production system type. The objectives of commercial cow/calf producers and purebred
breeders are similar; however, the management practices may be quite different. The goal
of most cow/calf producers is to produce the maximum pounds of calf at the most
economical cost, while the objective of the purebred breeder is to produce breeding cattle
for purchase by other breeders and commercial cow/calf producers.
The three principal areas considered in the selection of breeding animals are visual
appraisal, pedigree, and performance. Producers often consider all of these factors in the
selection of breeding animals. Depending upon the producer’s objectives, varying
degrees of emphasis are placed on the selection factors. For example, the purebred
breeder often places more emphasis on pedigree than does the cow/calf producer.
VISUAL APPRAISAL AS A BASIS OF SELECTION
Selection by visual appraisal has been responsible for much of the genetic improvement
of beef cattle. Visual appraisal can be a good indicator of frame size, muscle and body
structure, predisposition to waste, feet and leg structure, and breed character of the
individual’s offspring.
A close relationship exists between the appearance of a breeding beef animal and its
reproductive efficiency, a critical factor in the success of purebred and commercial
operations. Breeding cattle must be able to reproduce regularly over a long period of time
to be economically productive. Before discussing factors to consider in visual appraisal,
one must have knowledge of the parts of a beef animal (see Figure 1). An understanding
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of beef animal parts and their description is necessary for effective communication in any
segment of the beef industry involving live cattle or carcass evaluation.
The following characteristics of a beef animal should be visually appraised and then
combined with production records and pedigree analyses to do an effective job in
selecting beef breeding animals.
Body Structure
Body structure is a major factor in the visual evaluation of beef cattle. The general body
structure of the animal is a good indicator of production characteristics. Cattle with the
correct body structure will be more efficient producers, thus having more potential for
economic returns.
The neck of a beef animal should be moderately long, which is an indicator of growth.
The animal should be clean in the throat area. The loin and rump should be long, wide,
and level causing the animal to be long and strong in its back. Extremely short-bodied
and short-legged cattle are associated with excessive fat deposition and inefficient growth
rates. In comparison, excessively long-legged and long-bodied cattle are associated with
late maturity and low-quality grades. The round of beef cattle should be deep and wide
when viewed from the rear, with the widest portion being about midway between the tail
head and hock.
The shoulder should be well muscled but free of coarseness. Offspring with extremely
heavy, open shoulders can cause calving difficulties. A beef animal should be moderately
trim in its rear flank, underline, and brisket, and carry minimal excessive waste. At the
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same time, the animal should show good depth of body, indicating body capacity and
overall productiveness. An animal that has a wide, full heart girth, adequate spring of the
fore-ribs, and a wide chest floor and chest indicates proper growth and function of vital
organs. Adequate width between front and hind legs also indicates good body capacity
and muscling.
Soundness of Feet and Legs
Visual appraisal of structural soundness is useful in evaluating longevity and
productivity. For cattle to travel and remain sound during a long productive life, they
must have correct conformation of feet and legs. The legs should be squarely set under
the four corners of a beef animal and be reasonably straight. The shoulders should not be
too straight as this may be an indicator of leg problems. Animals that exhibit signs of
structural abnormalities (see Figure 2) should not be selected as potential breeding
animals.
Examples of common structural abnormalities of the feet and legs include:
Post-legged – hind legs are set too far back, thus making them too straight
Sickle-hocked – hind legs are set too far under the body
Knock-kneed – front legs are close at the knees and feet are “toed-out”
Pigeon-toed – front feet are “toed-in”
Bow-legged – hind legs are wide at the hocks and feet are “toed in”
Cow-hocked – hind legs are close at the hocks and feet are “toed-out”
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An animal’s productive longevity is largely dependent on its structural soundness.
Longevity is important in all phases of beef production because it affects the number of
replacement animals necessary to maintain a herd. An animal’s movement should be free
and easy as opposed to being uncoordinated, slow, stiff, and restricted. Animals with
uneven, small, curled, or twisted toes and crooked feet usually become lame and should
not be selected. Unsound feet, legs, and joints affect the ability of bulls to follow and
breed cows, which reduces herd productivity.
Breeding animals with feet or leg problems are not physically capable of being
productive over an extended period of time.
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Muscling and Muscle Structure
Evaluating muscling is another important factor to consider when visually appraising
beef cattle. Muscling is the source of meat for consumers, and therefore is essential to
evaluate. Muscling is indicated by conformation, overall thickness and fullness, and
muscular development in relation to skeletal size.
Bulls
Thick, heavy, long muscling is desired in bulls. This is indicated by length and size of
muscling in the forearm and gaskin areas, width and bulge of muscling in the stifle area
as viewed from the rear and side, width between the hind legs (both standing and
walking), thickness, length, and bulge of muscling in the back and loin, and expression of
muscling in the shoulder and round as the animal moves. Length of muscling is largely
determined by length of bone. If muscling is thick and bulging in one area of an animal’s
body, the animal is usually heavily muscled throughout the body. Animals with extreme
muscling, to the point of being impaired in movement or appearing “double-muscled,”
should not be selected.
Cows and Heifers
Muscling in females should be long, smooth, and of moderate thickness. In females,
short, coarse, bulky muscling is usually a sign of poor reproductive efficiency and low
milking ability. A female’s overall body shape should have a slightly angular appearance,
with a slight skin fold shown by the dewlap down the throat and in the brisket area. The
shoulders should be moderately muscled and “clean.” The shoulder blades should extend
to the top of the vertebrae, giving a lean appearance to the top of the shoulders.
Frame or Skeletal Size
Frame size is a numerical description that refers to an animal’s skeletal size, that is, its
height and body length in relation to its age. Frame size indicates growth, but also is an
indirect measure of the composition or fat-to-lean ratio, of beef animals. Frame size can
be used to approximate projected mature size, and to characterize performance potential
and nutritional requirements of an animal. Substantial frame score variation exists among
cattle. Ideal frame scores and desired body types differ depending on the production
scenarios, such as varying ration formulations, management systems, and market
endpoints.
Researchers at the University of Wisconsin have developed a system under which cattle
can be classified into seven frame types. Using this system, most British breeds of cattle
will fall into frame sizes 1 to 5 and most exotic cattle will range from frame sizes 3 to 7.
Shown in Figure 3 are the seven frame types of beef cattle. Lower frame scores are
descriptive of cattle that tend to be shorter in stature, earlier maturing for their age, and
tend to “finish” and mature at lighter body weights. Higher frame scores are descriptive
of cattle that are taller in stature, have a slower rate of maturation, and tend to finish and
mature at relatively heavier body weights. Large framed cattle tend to be leaner, grow
faster, and produce more pounds of edible beef per day of age than smaller framed cattle.
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The Beef Improvement Federation (BIF) used the measurement of hip height and
correlated it with the seven frame types. They found that linear measurement of wither
height or hip height is the most accurate predictor of frame type. When taking this
measurement, care must be taken to ensure that the animal is standing up well on a level
surface, and the measurement is taken from the same point on each animal measured. Hip
height measurements should be taken at the hip directly above the hook bone. Tables 1
and 2 show the relationship of hip height to frame score at a given age for heifers and
bulls as determined by the BIF.
Most commercial producers use medium framed cows (900 to 1,300 pounds at calf
weaning time), as they are more economical. Usually, the cows are bred to large framed
bulls. Typically, small framed cows produce calves with less growth potential and have
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little salvage value. Large framed cows are not as economical because they have higher
body maintenance requirements. However, some large framed cows are required in
purebred herds to produce large framed bulls.
Animal scientists at Texas A&M University recommend that bulls be a minimum of
frame size 6 (51 inches at the hip) at 12 months of age and weigh 22 or more pounds for
each inch of height (minimum of 1,120 pounds). Mature bulls should weigh a minimum
of 1,700 pounds and have a minimum hip height of 57 inches. These researchers also
recommend that bulls weigh at least 600 pounds at weaning and exhibit rapid, efficient
growth rates, thus maximizing muscle production and minimizing fat deposition.
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Reproductive Soundness
Bulls
Bulls should be free of eye problems (e.g., cancer, pinkeye, and cloudy eyes) because
good vision is required to find cows that are in heat. As mentioned earlier, soundness of
feet and legs is critical because bulls will have to travel in order to mount and mate with
females. The testicles should be well developed, uniform in size, and properly balanced
in relation to the age and size of the bull. The scrotum and testicles should be a minimum
of 30 centimeters (approximately 12 inches) in circumference on a twelve-month hold
bull to indicate adequate reproductive ability. Although bulls with Brahman breeding will
exhibit a more pendulous sheath, the sheath region should be “tight” or free from excess
skin folds and obstructions. Bulls should exhibit adequate libido, or sex drive.
Cows and Heifers
A productive cow will have a large spring of ribs, indicating adequate body capacity to
carry a large, healthy calf. Females should be wide and long from hip to pin bones and
deep from pins to the stifle joint, indicating calving ease. However, the widest portion of
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the fertile cow should be the midrib. The udder should be strongly attached with a level
floor and the teats should be proportional to body size.
Predisposition to Waste
The location and degree of fat deposition is very important in the beef industry. Finish
affects carcass yield. Consumers prefer an optimum combination of intramuscular fat
(marbling) and total fat (finish). Finish and marbling contribute to the juiciness, flavor,
and palatability of meat. A correct degree of finish is necessary to ensure proper quality
and high cutability in the carcass. The degree of finish on a breeding animal will vary
depending on the energy level and amount of feed the animal is being fed. The season of
the year is also a factor in fat deposition.
Bulls
Bulls should naturally show an even, thin distribution of fat, even when they are being
fed heavily or during the nonbreeding season. Excessively fat bulls will lack libido.
Indicators of predisposition to excessive waste are large amounts of loose hide in the
dewlap or brisket, excessive depth in the flank, and loose hide in the twist.
Cows and Heifers
Females should never be fed to excessively fat conditions. Fatty tissue is deposited in
their udders and around their reproductive organs, resulting in reduced milk production
and lower reproductive rates. Females will normally deposit more fat in the brisket, along
the underline, and over the ribs and back than will bulls, especially during their dry
season. The fat deposits can be advantageous if not excessive, because these cattle will
require less feed during the winter, in comparison to “poor-doing” or “hard-fleshing”
cattle.
Breed Character
Each particular breed of animal is composed of a unique combination of genetics that
allows the animal to be recognized as a member of that breed (i.e., its phenotype). Breed
character is the “trademark” or specific identity for the breed that the animal represents.
In purebreds, the traits that distinguish one breed from another include:
• Hair color or hair color patterns
• Head size and shape
• Ear size, shape, and carriage
• Dewlap characteristics
• Sheath characteristics
• Overall body shape
• Horned or polled
If an animal is being purchased as a purebred, it should exhibit the significant
characteristics of that breed thus making it eligible for registration. Breeders should
purchase the breed or breeds of cattle that will produce the type of offspring most
desirable for their production system and end market.
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Temperament
The temperament, or disposition, of the breeding animals one selects can be important to
their overall productivity. Genetic makeup and environmental conditions are two factors
that affect the disposition of cattle. A producer’s handling methods also have a significant
impact on an animal’s temperament. All breeds of cattle have some individuals that have
“bad” or undesirable temperament, but some breeds have a tendency to be more nervous
than others. Frequently, indicators of bad temperament are high-headedness, nervousness,
frequent urination, charging, and kicking. Temperament may be even more critical in the
cows that are selected, because gentle, easy-handling mothers usually raise better calves.
On the other hand, a bad tempered bull can be dangerous regardless of his genetic
superiority. Cattle with very poor dispositions should be culled to prevent human injury,
decrease excitability of other animals, and minimize repair costs of facilities from
damages caused by destructive behaviors. However, it should be noted that culling is not
an effective solution if bad handling is causing the problem. In this case, the handling
methods and facilities should be examined.
Sales are often not a good time to make decisions about an animal’s temperament.
Frequently, sale animals will express abnormal behaviors because of pre-sale handling
and processing. These behaviors may not be a true indicator of their temperament under
normal pasture conditions. When possible, selection in the pasture is a more desirable
option for this trait.
Conformation Scores
A conformation score is a characteristic often provided with sale cattle. The criteria for
establishing the score (usually form, shape, and visual appearance) may be provided by a
breed association, an individual breeder, or some other authority. Figure 4 is an
evaluation form for a conformation scoring system developed by Mr. Frank Litterst,
Texas A&M University, Dr. Randall Grooms, Texas Agricultural Extension Service, and
Mr. J. D. Sartwelle, Jr., owner, Port City Stockyards, Sealy, Texas. This system was
devised to evaluate bulls at the Houston Livestock Show and Rodeo All-Breeds Bull
Sale. The factors to consider in using this system have been discussed earlier in this topic.
This evaluation form could be used in the selection of females as well as bulls for a
breeding cattle herd.
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PEDIGREE AS A BASIS OF SELECTION
Pedigree data is information on the genotype or performance of ancestors and collateral
relatives of an individual. When using pedigree as a basis of selection, the animals are
selected based on the merit of their ancestors. If a pedigree is used, greatest value should
be placed on the most recent ancestors because of their close genetic relationship to the
animal to be evaluated. The percentage of genes in a superior animal is halved in each
successive generation; therefore, parents and grandparents are the only animals that will
contribute significantly to an offspring’s genotype.
Frequently, too much emphasis is placed on outstanding ancestors several generations
back in the pedigree. Sometimes the pedigree of a particular animal may become very
popular because of a fad. However, this may change rather quickly and often the value of
the pedigree will decrease, or the characteristics that were highly sought after previously
may even be discriminated against in the future.
The best uses of pedigree information are in the selection of young animals before
production and performance records are available and in the selection of highly heritable
characteristics such as longevity, yearling weight, and mothering ability. Pedigree
information is also useful in identifying genetic abnormalities, as well as selecting for
traits expressed only in one sex. However, more emphasis should be placed on individual
performance and progeny testing than on pedigree.
PERFORMANCE AS A BASIS OF SELECTION
Performance testing is the measuring of traits that can be observed and may include either
individual performance or progeny testing. Testing usually focuses on the traits that have
the greatest economic importance. Potentially, the most improvement is offered by those
traits that are highly heritable as indicated in Table 3. The heritability percentage
identifies that portion of variation that is passed on from parent to offspring.
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There are considerable differences in cattle regarding the transmission of economically
important traits such as birth weight, mothering or milking ability, weaning weight,
yearling weight, efficiency of gain, carcass merit, and conformation score. However,
genetic improvements can be made by evaluating individual performance criteria and the
results of progeny testing. One must understand that these traits are affected by the
environment, as well as by genetics. Usually, the most accurate method of selecting cattle
is an approach that couples individual performance and progeny testing.
Measurements of Reproductive Performance
Reproductive performance has the highest economic value of all the traits. Understanding
reproductive performance data and applying it to beef cattle management can help
producers identify and measure efficiency and progress of production.
One of the most important measures of reproductive performance of a profitable breeding
operation is the weaned calf crop percentage. For each 10% drop in calf crop weaned, an
increase of about 20% occurs in production costs (as determined under Texas conditions).
Reproductive performance can be improved through selection based on carefully kept
records of reproduction. Reproductive records that are helpful include conception rate,
calf crop (percentage born and weaned), calving interval, and birth weight relative to
calving ease.
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Conception Rate
The conception rate of a herd is determined by comparing the number of breeding age
females that conceive or become pregnant to the total number of breeding age females
that were exposed to a bull during the breeding season. A conception rate percentage can
be calculated by using the following formula.
Calf Crop Percentage (Born)
Calf crop percentage is determined by dividing the number of calves born by the number
of cows that were exposed to a bull during the breeding season.
Calf Crop Percentage (Weaned)
Percentage weaned is computed by dividing the number of calves weaned by the number
of cows that were exposed to a bull during the breeding season.
Calving Interval
This measure of reproductive performance is the average length of time in days between
successive parturitions or calvings for all of the breeding age females in a herd. It would
be calculated for each cow and then an average would be computed for the herd, which
would be a measure of the fertility of the herd.
Cow A
Calving Dates: 3/1/00 and 3/1/01, then Calving Interval = 365 days
Cow B
Calving Dates: 4/1/00 and 8/1/01, then Calving Interval = 485 days
Cow B should be culled for poor reproductive efficiency.
Birth Weight Related to Calving Difficulty
Average birth weights of offspring should be considered when selecting breeding beef
cattle because they are directly related to ease of calving. Calving difficulty (dystocia)
can increase calf losses, cow mortality, and veterinary and labor costs, as well as delay
return to estrus and decrease conception rates.
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Calves that are heavy at birth require a larger birth canal or pelvic area for normal
delivery than do lighter calves. Birth weights in excess of 90 pounds usually create
calving difficulty. Heifers are more likely to experience calving difficulty; so more care
must be taken when selecting bulls for heifers than for cows. Many producers of breeding
stock, especially bulls, will provide buyers with calving ease information such as calving
difficulty scores (see Table 4).
The primary goal of every cow/calf producer should be to produce one live healthy calf
from each cow every twelve months. Cows that are incapable of meeting these standards
should be culled. Palpation can assist producers in early detection and elimination of poor
producers. Heifer replacements should be selected only from cows with excellent
reproductive records.
Fertility Testing of Bulls
Fertility testing is an important consideration when selecting a bull. Young bulls as well
as old bulls should be fertility tested before being used. Fertility testing involves physical
and visual evaluation of the bull’s reproductive soundness.
A breeding soundness exam (BSE) is a common method for fertility testing bulls. A BSE
includes a physical examination of the bull’s reproductive system, a measurement of the
bull’s scrotal circumference, and an evaluation of the bull’s semen.
The bull’s external genitalia can be examined visually and should not exhibit any
structural abnormalities. Internal organs of the bull’s reproductive system can be
examined for size, shape, and consistency through rectal palpation. Scrotal circumference
should be evaluated because of its relationship to sperm production and semen volume.
The bull’s semen should be evaluated for volume, morphology, and motility.
If conception rates are a problem, fertility testing of bulls should not be overlooked. An
entire breeding season could be lost by using an infertile sire. It is important to remember
that previously tested, fertile bulls may later experience infertility because of disease,
injury, or other reasons. Therefore, it is a good practice to test for fertility before each
breeding season.
Measurements of Growth and Gain Performance
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Weaning Weights (Adjusted to 205 Days)
Weaning weights are used to evaluate differences in mothering ability of cows and the
growth potential of calves. For best estimates of genetic worth of weaning weight, it is
necessary to adjust individual calf records to a standard basis. Most organizations that
record weaning weights use weights taken between 160 to 205 days and adjust this
weight to a uniform age of 205 days. This procedure is summarized by the following
formula.
If the actual birth weight is unknown, 70 can be used for this figure. The 205-day weight
should then be adjusted for the age of the dam and for the sex of the calf. This is
necessary for uniformity in evaluating 205-day weights. Table 5 can be used to adjust the
205-day weights to a mature dam equivalent for bulls and heifers.
Note: Depending on the age of the dam and the sex of the calf, select the appropriate
number of pounds to be added to the adjusted 205-day weight.
Weaning weight ratios within sex groups are calculated by dividing each individual
animal’s 205-day weaning weight, adjusted for age of dam, by the average of its sex
group. Weaning weight ratios provide a record of each animal’s deviation from the
average of its contemporaries. It is calculated by using the following formula.
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Yearling weights at 365 days are particularly important because of their high heritability
and high genetic association with efficiency of gain. Yearling weight is the best
performance measure for selecting bulls. It is closely related to the eventual market
weight of the steers to be produced. Usually, the weights are adjusted to a 365-day basis,
yearling weight, or to a 550-day basis, long yearling weight. The following formula is
used for making the adjustment.
To compute the 452 and 550-day adjusted weights, 247 and 345 should be substituted
respectively for 160 in the previous formula. A yearling weight ratio can be calculated by
comparing the individual’s yearling weight to the average of a specific sex group. All
animals in a sex group must have been given similar environmental treatment for the
weights and ratios to be meaningful and comparable. The following formula is used for
this calculation.
Individual rate of gain testing is usually conducted on bull calves or short yearlings to
determine their ability to grow. Testing the rate and efficiency of gain is very important
in bull selection as the timing and length of this test period coincides with the finishing
period of the feedlot phase for the calves that the bulls will sire. Most of the tests are
conducted for a period of 140 days. An initial weight is taken at the beginning of the test
and a final weight at its conclusion. The formula for determining rate of gain is shown
below.
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When making comparisons of animals on gain tests, particularly from central gain test
stations, weaning weights and weight per day of age should be considered along with the
gain test results. According to researchers at Texas A&M University, bulls on gain tests
should have an average daily gain of 3.5 pounds requiring less than seven pounds of feed
for each pound of gain. Another factor to consider is that performance on an animal’s test
is influenced by the handling and management received prior to the test. Therefore, it is
necessary to include pre-test adjustment periods.
Central test stations are locations where animals from numerous herds are collected to
evaluate differences in specific performance traits under uniform conditions (e.g., a gain
test). Central test data is valid for comparison of animals only within that particular test
and not between years and test stations. Even if all test stations followed similar
guidelines, comparisons of performance of animals at different locations would be invalid
because of differences in environment, nutrition, and other factors. Ratios should be
calculated only within a breed within a test group. Producers should try and find a test
station that has nutritional and environmental conditions similar to their own production
systems. The data provided by central test stations can be useful selection and marketing
tools.
A low weight per day of age and a high gain per day of age while on test indicate an
extremely low weaning weight or a long period of little or no gain before the cattle were
placed on test. This could mean much of the superiority in rate of gain while on test is
compensatory gain instead of genetic ability to grow rapidly. The compensatory gain may
be a result of low weaning weights because of poor mothering ability or other
environmental factors. The following formula is used to calculate the rate of gain ratio.
This is a comparison of one animal with the other animals on the 140-day test. A ratio of
100 is the group average. An average daily gain ratio of 110 indicates that a bull is 10%
above the group average for rate of gain.
Weight Per Day of Age
The weight per day of age of an individual can be a good indicator of genetic growth
potential. However, this measurement contains a potentially unreliable variable because it
only uses the actual weight of the individual and divides it by the actual age in days of the
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animal. For example, there are not any adjustments in this figure for the age or mothering
ability of the individual’s dam or other environmental factors such as nutritional level
after weaning. Any of these variables could influence, either negatively or positively, the
animal’s genetic ability for growth. The formula for calculating weight per day of age is
shown below.
EXAMPLE OF PERFORMANCE DATA FOR A BULL
Many breeders provide a considerable amount of information on sale animals. This
information is beneficial to prospective buyers in evaluating the efficiency and
productivity of a bull, which aids in selection. The type and amount of information
provided varies with the breeder and sale. Figure 5 is an example of the information
provided in an advertisement for bulls completing a test and offered through a sale.
On-Off Date – Refers to the dates the bull was placed on and taken off test.
Code I.D. – The name of the bull and the brand used to identify it.
Sire – This is the sire of the bull placed on test.
DOB – Date of birth. (This bull was born 10-19-99.)
Int. Ht. – Hip height of the bull when placed on gain test (48 inches).
End Ht. – Hip height of the bull when taken off test (54.5 inches).
HT. Grown – Grown height or frame score (6.5). This score is obtained by referring to
the chart developed by the Beef Improvement Federation.
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Adj. 205 – Adjusted 205-day weight (581 lbs.). The bull’s actual weaning weight is
adjusted to 205 days and for age of dam.
Wean Wt. – Weaning Weight (600 lbs.). This is the actual weight of the bull at weaning.
Intl. Wt. – Initial Weight (855 lbs.). The weight of the bull when placed on test.
140-Day Act. Wt. – 140-day actual weight (1225 lbs.). The weight of the bull at the
conclusion of the test.
140-Day Cum. ADG – 140-day cumulative average daily gain (2.643 lbs.). The average
daily gain during the 140-day test.
ADG Rat. – Average daily gain ratio (99.9). The bull’s ADG compared to the other bulls
on test.
WT. Day Age – Weight per day of age. This will indicate the daily growth of the bull
(2.69 lbs.).
WT. Day Age Rat. – Weight per day of age ratio (102). With a 102 ratio, this bull is two
percent better than the average for the group.
Day of Age – The actual number of days of age (455).
Scrotal Circum. – Scrotal Circumference (36 cm). Used as an indicator of fertility.
PROGENY TESTING
Progeny testing is a method of evaluating an animal’s breeding value by observing its
transmitting ability through a study of the characteristics of its offspring. It is the most
accurate method of selection when adequate tests are conducted. Progeny testing is
particularly useful in selecting for carcass traits (when good indicators are not available
on live animals), for sex-limited traits (milk production and mothering ability), and for
traits with low heritability. Progeny testing has an advantage of greater accuracy over
other tests. Through its use, breeders can determine the differences in the genetic ability
of their cattle.
The primary disadvantage of progeny testing is that it is not possible to include cows in
the testing program. The individual cow will not produce enough calves in a lifetime for
an accurate evaluation, because the generation interval for cattle is too long. Although not
completely accurate, cows can be selected on their production by evaluating their calves
at weaning. This factor is based primarily on the cow’s mothering ability.
Carcass Merit
Carcass merit is a production trait of a bull that can only be measured through progeny
testing. Carcass merit is measured primarily by carcass weight, tenderness, quality grade,
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and yield grade. Many cattle breed associations have devised a system for recognizing
superior meat sires. Usually, the evaluation of 8 to 12 carcasses of a bull’s progeny will
indicate his probable transmitting ability of carcass traits. However, when evaluating a
sire’s progeny for carcass merit, the progeny selected for evaluation should be the result
of random matings, be the same sex, and be reared under similar environmental
conditions.
Quality Traits
When evaluating a sire’s progeny for carcass merit, the carcasses are graded for quality
traits based on the overall palatability of the edible portion of the carcass. USDA quality
grades include prime, choice, good, standard, commercial, and utility. These grades are
determined by the maturity, color, texture, amount, and firmness of lean muscle as well
as the marbling within the lean and degree of finish on the carcass.
Quantity Traits
The carcass is also graded for quantity traits based on the amount of marketable meat the
carcass will yield. USDA yield grades range from 1 to 5, according to the amount of KPH
fat, external fat thickness over the 12th rib, area of the ribeye muscle at the 12th rib, and
hot carcass weight. Cattle producers should select sires capable of producing superior
beef carcasses. Beef cattle specialists at Texas A&M University recommend that sires
selected produce progeny that will yield carcasses grading at least low choice with a
minimum “small” degree of marbling and a maximum of 0.04 inches of outside carcass
fat/100 pounds of live weight. The carcasses should contain ribeyes with areas of 1.1 to
1.4 square inches/100 pounds live weight, have a minimum dressing percentage of 60%,
and consist of 50% or higher of boneless retail trimmed loin, rib, round, and chuck.
USING ESTIMATED BREEDING VALUE (EBV) AND EXPECTED PROGENY
DIFFERENCE (EPD) IN SELECTING BEEF CATTLE
Estimated Breeding Value (EBV)
Estimated Breeding Value (EBV) is an estimate of an individual’s true breeding value for
a trait. EBV is based on the heritability of the trait and the performance of the individual
and close relatives. EBVs for growth traits are generally expressed as ratios. EBVs are
more accurate than individual performance records (IPR); therefore they are more useful
in selecting breeding cattle. EBV includes the individual’s performance records as well as
records of collateral relatives such as the sire, dam, sire of dam, and half brothers and
sisters. EBVs are valuable in the selection of young bulls and females for birth weight,
weaning weight, yearling weight, and mothering ability (milk).
A bull can transmit only one-half of his superiority for a trait to his offspring, as
calculated by EBV. For example, a bull with an EBV of 108 for yearling weight has a
genetic potential or estimated breeding value of 8% above the average of those bulls to
which he was compared. The value to be placed on this figure is dependent on whether he
was compared to other bulls from his herd, to bulls from several different herds, or to
many other bulls of his breed.
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Expected Progeny Difference (EPD)
One-half of the EBV is equal to the Expected Progeny Difference (EPD). Using the same
bull mentioned above, the amount of change that could be expected in yearling weights
of his offspring would only be a 4% increase. The reason the bull transmits only 4% is
because the dam transmits the other half of the trait.
If a bull has an EBV for yearling weight of +60 pounds, it would have an EPD of +30
pounds and be expected to add 30 pounds in yearling weight to a herd in comparison to a
bull with an EPD of zero for the same trait. Expected progeny differences have replaced
EBVs in most breed association programs. EPDs provide a prediction of future progeny
performance of one individual compared to another individual within a breed for a
specific trait. The most common EPDs reported are birth weight, milk, weaning weight,
maternal, and yearling weight. EPDs are based on a herd or breed average. Different
breeds have different bases; therefore, it is very difficult to compare EPDs across breeds.
Some adjustment factors exist for comparisons across breeds, but the information is less
accurate than within-breed comparisons. Accuracy (ACC) of the EPD is given for each
trait. The accuracy value reflects the degree of relevance of the information used to
calculate an individual EPD. It is a measure of confidence that the EPD reflects the true
genetic merit of an animal. The accuracy can range from zero (very poor) to one
(extremely accurate).
Accuracy can be classified into three basic categories, low (.00 – 0.50), moderate (0.51 –
0.70), and high (0.71 – 1.00). Accuracy indicates whether the EPD estimate is based on
solid herd data or whether it is little more than a guess. Highly accurate EPDs are very
reliable, the greater the accuracy of the EPD, the more reliable the data. However,
accuracy does not indicate how variable an individual’s offspring may be.
The use of EPDs allows producers to make comparative selection decisions for beef
cattle traits of economic importance. In selecting a bull, the breeder should review the
individual performance data first and then review the pedigree. The next step is to review
the Pedigree Index (PI). If a bull’s sire and maternal grandsire (sire of dam) are included
in the breed summaries, a pedigree index can be calculated on traits of interest and their
EPDs can be evaluated.
A young bull to select would be one with a superior IPR, would have been sired by a
superior bull, and would have been calved by a cow sired by a superior bull. This is the
best method of selection next to buying a proven superior bull. The most economical way
a commercial breeder can obtain the use of a proven superior sire is with artificial
insemination (A.I.).
It is fairly simple to use performance information in selecting A.I. sires. First, the breeder
must determine the traits on which the bull will be selected. Most breed associations
publish a sire summary on an annual basis in order to provide current genetic evaluations
on progeny-proven sires within their breed. The summaries include calculated EPDs for
the traits of the sires listed in the summary. Tables 6 and 7 are examples of a sire’s EPDs
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in a sire evaluation report. The information presented in sire summaries can be beneficial
to purebred and commercial producers alike.
The systematic use of sire summaries, in conjunction with other performance and
pedigree data as well as visual appraisal, can be beneficial tools for beef cattle producers.
Knowledge of selection methods can help producers reduce the risks associated with beef
cattle selection and improve the genetics and productivity of their herds.
BW – Birth Weight - Relative birth weight, excluding maternal influence.
WW – Weaning Weight - Weight at 205 days of age, excluding maternal influence.
YW – Yearling Weight - Weight at 365 days of age, excluding maternal influence.
MILK – Maternal Influence - (lbs. WW) Maternal influence produced by daughters of
this individual.
TM – Total Maternal - Milk EPD + 1/2 WW EPD (expectations of daughters of this
individual).
CE – Calving Ease (direct) - Ease of calving of calves sired by this individual.
CE DTRS – Calving Ease Daughters - Ease of calving experienced by daughters of this
individual.
GL – Gestation Length - (days) Predicts average difference in length of gestation of
daughters of this individual.
SC – Scrotal Circumference - (cm) Circumference is an estimate of age at puberty of
progeny.
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CWT – Carcass Weight – (lbs.) Hot carcass weight. A measurement of body size and
genetic growth potential.
REA – Rib Eye Area – (in.2) A measurement of the longissimus muscle over the 12th rib.
MARB – Marbling – USDA marbling degrees. Evaluated in the rib eye between the 12th
and 13th rib.
FT – External Fat Thickness – (in.) An important factor in red meat yield (percent retail
cuts).
ACKNOWLEDGEMENTS
Holly Hutton, Graduate Assistant, Department of Agricultural Education, Texas A&M
University, researched and developed this topic.
Dr. M. Craig Edwards and Larry Ermis, Curriculum Specialists, Instructional Materials
Service, Texas A&M University, reviewed and edited this topic.
Dr. L. R. Sprott, Extension Beef Cattle Specialist, Texas Agricultural Extension Service,
Texas A&M University, provided information in the development of this topic.
Vickie Marriott, Office Software Associate, Instructional Materials Service, Texas A&M
University, edited and prepared the layout and design for this topic.
Christine Stetter, Artist, Instructional Materials Service, Texas A&M University,
prepared the illustrations for this topic.
Sarah Danek, Graduate Student Worker, Texas A&M University, updated the format of
this topic.
REFERENCES
Dhuyvetter, John. (1995). Beef Cattle Frame Scores. AS-1091. North Dakota State
University Extension. [Online]. Available:
http://www.ext.nodak.edu/extpubs/ansci/beef/as1091w.htm [July 2001]
“Guidelines for Uniform Beef Improvement Programs.” Stillwater, OK: Beef
Improvement Federation,
1990.
Instructional Materials Service. “Livestock Evaluation Handbook,” Catalog No. 4032.
College Station, TX: Instructional Materials Service, Texas A&M University, 2001.
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Taylor, Robert E. and Thomas G. Field. Beef Production and Management Decisions. 3rd
ed. Upper Saddle River, NJ: Prentice Hall, 1999.
Taylor, Robert E. and Thomas G. Field. Scientific Farm Animal Production. 6th ed.
Upper Saddle River, NJ: Prentice Hall, 1998.
GLOSSARY OF TERMS
Carcass yield - Percentage of the live animal weight that becomes the carcass weight at
slaughter.
Collateral - Related to same ancestry but not a direct descendant (e.g., brothers and
sisters).
Commercial cow/calf producer - Producer of beef cattle primarily concerned with pounds
of beef produced; the ultimate product of this type of operation is slaughter beef.
Compensatory gain - An accelerated rate of growth after a period of restricted growth.
Culled - Having eliminated one or more animals from a herd.
Cutability - Fat, lean, and bone composition of a beef carcass; synonymous with “yield
grade.”
Double-muscled - A genetic trait where muscles are greatly enlarged, rather than being
duplicate muscles.
Dry season - Time when a female is nonlactating.
Fertility - Capacity to initiate, sustain, and support reproduction.
Finish - The degree of fatness of an animal.
Generation interval - Average age of parents when their offspring are born.
“Hard-fleshing” - Designating an animal that has difficulty in gaining sufficient weight.
Hot carcass weight - Weight of the carcass as it leaves the slaughter operation, just prior
to being chilled.
Intramuscular fat - Fat within muscle, also called “marbling.”
KPH fat - Kidney, pelvic, and heart fat. An estimate of fat in the kidney knob, pelvic, and
heart areas as a percentage of the chilled carcass weight.
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Longevity - Life span of an animal; usually refers to the number of years a cow remains
productive.
Morphology - The form and structure of an organism or any of its parts.
Palatability - Degree to which food is sufficient in flavor, juiciness, and tenderness as it
relates to being eaten.
Palpation - Examining (by touch) a developing fetus.
Parturition - Process of giving birth.
Pedigree - The record of the ancestry of an animal.
Pendulous - Hanging loosely.
Performance testing - The testing of individuals themselves for various inheritable
growth traits such as weaning weight, rate of gain, yearling weight, etc.
Phenotype - The characteristics of an animal that can be seen or measured.
“Poor-doing” - Designating any meat animal in thin condition.
Progeny testing - The testing of the offspring of individuals for various growth and
carcass traits.
Purebred breeder - Producer of full-blooded beef herd sires or replacement heifers to be
used by commercial cow/calf or other purebred breeders.
Replacement animals - Cattle brought into a herd to replace those that were culled and
sold, or those that died.
Salvage value - Value assigned to an animal at market at the end of its useful life.
Short yearling - An animal that is slightly less than a year old.
Sire - The male parent.
Sire summary - A report of a breeding male’s traits including birth weight, weaning
weight, yearling weight, and maternal breeding value.
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