Animal Selection and Evaluation
Livestock Evaluation
Why Evaluate Livestock?
• Success in the production of livestock
depends on the ability to select animals
efficient in their production and
reproduction capabilities.
• Develop ability to recognize carcass and
breeding merit, as well as, understand the
economic value differences when
comparing livestock.
To Predict Production
Performance...
• Rate of gain is amount of weight
gained on a per day basis.
• Feed efficiency is the amount of feed
consumed divided by the amount of
weight gained. Approximate estimate
for each specie (lbs. of feed/lbs. of
gain): Cattle 7:1, Sheep 5:1, Swine
3:1.
To Predict Production
Performance...
• Livestock with greater length, width, and
depth of body tend to have a greater ability
to grow and gain at a faster rate.
• Performance capabilities are difficult to
predict from visual evaluation. Production
and performance records of relatives are
good indicators.
To Predict Production
Performance...
• Performance records of relatives help to
estimate growth potential of the individual.
Terminology used is:
– Cattle: birth weight, weaning weight, yearling
weight, etc.
– Swine: 21 day litter weight, days to 230 lbs.,
sow productivity index, etc.
– Sheep: type of birth (single, twins, triplets), 90
day weight, ewe index, etc.
To Predict Production
Performance...
• There is no agreement as to the ideal
size or weight of any species. This is
influenced by:
– Economy: feed prices, production costs,
supply and demand for meat.
– Consumer: fat content and portion size of
product.
– Environment: Amount and quality of feed
resources, temp., rainfall, etc.
To Predict Reproductive Performance in
Beef Cattle
• Calving ease may be estimated to a certain extent
by estimating:
– Width b/t pin bones. More width generally
indicates greater width in the birth canal.
– Slope of rump. Pin bone should be slightly
below the hook bone when the animal is viewed
from the side.
– Shoulder should blend smoothly into the neck
at both the top and bottom of the shoulder when
viewed from the front.
To Predict Reproductive
Performance in Beef Cattle
• Milking ability may be estimated by:
– Udder development, teat placement, and
teat quality.
– Examine past production record of the
dam and female offspring of the sire.
• Production records from the parents
are the best way to evaluate
reproductive performance and
capabilities.
To Predict Reproductive
Performance in Beef Cattle
• Skeletal soundness:
– If properly designed, an animal should have
free, easy movement.
– If an animal has mobility problems at an early
age and light weight, it will only be magnified
in later life.
– The animals feet, legs and body should indicate
a long, productive life.
Correct (Right) / Incorrect (Left)
Structures
To Predict Reproductive
Performance in Sheep
• Production records from the dam are used
extensively. They should provide the
following:
– Multiple birth ability.
– Number of lambs raised vs. number born.
– Weaning weight, milking ability.
To Predict Reproductive
Performance in Sheep
• Skeletal correctness
– Straight lined, level top, and legs are
straight, and set wide apart, both front
and rear.
– Must have freedom of movement.
• Growth potential
– Select sheep that have the ability to
grow rapidly
– Capacity: length, width, and depth of
body
Correct Structure
To Predict Reproductive
Performance in Swine
• Production records are very useful in
identifying superior individuals.
– Litter size, number of pigs born vs. number
raised.
– Litter weight.
– Slow productivity index.
– Days to 230 lbs.
To Predict Reproductive
Performance in Swine
• Skeletal correctness
– It is essential that hogs are structurally correct
because many are raised in confinement
systems (i.e., concrete slotted floor buildings)
– More early level rump and top, sound feet and
legs, width of body, and long and fluid stride.
• Growth potential: Hogs with more capacity
have a tendency to grow more rapidly.
Correct (left)/Incorrect (right)
Structure
To Predict Reproductive
Performance in Swine
• Milking ability
– Select gilts that have a minimum of 6
functional, evenly spaced nipples on each side
of the underline.
– Nipples should be prominent.
– Avoid an underline that has several
abnormalities (i.e., pin nipples, inverted, etc.)
Correct Nipple Structure
What is an Ideal Market Animal?
Beef
• Ideal market beef should:
– Quality grade few choice which means
marbling in the meat and under 24 months of
age.
– Yield grade 1 or 2 which means a minimum of
fat and more muscle.
– Average back fat of .4 in. (measured at 12th
rib.)
Location of 12th Rib
Beef
• Ideal market beef should:
– Required ribeye area: Base 600 lb. carcass
needs 11.0 square in.
– Yield a carcass weighing between 500 and 750
lbs. to best fit market demand.
Beef
• The consumer’s recent trend toward
health awareness has influenced the
meat industry tremendously. For
example:
– USDA grading procedures have
changed. Greater value for lean, heavy
muscled cattle.
– Poultry and fish consumption have
increased greatly due to their lower fat
and lower cholesterol content.
Beef
– The fat content in 7 cuts of beef rank between
the chicken breast and thigh. (Not as fat as
consumers think.)
– The beef market is now focusing its promotion
on what consumers want - - convenience.
Beef
• Packer concerns:
– Cattle are purchased by the pound - fat is worth
about 1/10 of what lean meat is worth.
– Consequently, the packer loses money on fat
cattle.
Beef
• Producer concerns:
– Fat is less efficient to produce than muscle so
cattle gaining fat eat the same amount of feed
but gain less efficiently.
– Packers do not want to buy cattle that are
excessively fat.
Swine
• Ideal market hog should:
– Be lean and heavy muscled.
– Have a width through a ham equal to or greater
than the width through the shoulder and both
should be wider than the back.
– Have average back fat thickness of less than 1.0
inches (measured at the 10th rib).
– Have a minimum of 5.0 in. of loin eye.
Location of 10th Rib
Swine
• Ideal market hog should:
– Should be yield grade U.S. No. 1, which
depends on the amount of back fat and muscle.
– Carcass merit is an indication of the amount of
muscle/meat the carcass contains.
Sheep
• The ideal market lamb should:
– Be heavily muscled with superior conformation
and correctness.
– Have a 2.5 square in. ribeye or larger.
– At market weight have .1 to .2 in. of back fat
(measured at 12th rib) and be uniform in its fat
cover.
– Have a leg score of low choice or better.
– Be uniform in its thickness from head to dock.
Location of 12th Rib
Sheep
• The reasons for the change in the market
lamb desired today are very similar to the
reasons for the change in the type of market
steer.