Transcript Whole Body Animal Growth

WHOLE BODY
ANIMAL GROWTH
ANSC 590 ANIMAL GROWTH
AND DEVELOPMENT
GROWTH CURVES
Represents an increase in size relative to
a period of time (figure 9.1)
 Often impacted on compositional levels of
varying tissues ie. Muscle, fat, bone, CT
 Dependent on plane of nutrition and stage
of development
 Four phases of growth (figure 9.5)
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AGE and MATURITY
Chronological versus physiological
 Maturity is the point in time when an
animal reaches its highest level of
complexity or development
 Absolute growth rate: utilizes units
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 ADG,
WDA, Birth, Weaning, etc. (Figure 9.9)
 Growth rates of various tissues (figure 9.11)
Changes in Body Measurements
Quantifiable
 Carcass length in pork – value
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 Standard
reference points of measurement
LEA/REA (LD muscle)- cross section
 FT (SubQ) – where is the best place to
measure?????
 Body weight measures (table 9.2)
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Body Measures
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Empty body wt.
 Withhold
feed and water for 24 hours prior to
slaughter to secure shrunken weights
 Research methods: withhold feed for 12-24
hrs. prior to weighing if conducting research
 Pasture gain test
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Conduct a pre and post weight (shrunk wt. if less
than 90 day trial)
Dressing percent
Removal of everything but the carcass
 Factors that affect DP: fill, muscle, fat,
hide, etc.
 Assessment of value in the animal industry
Table 9.3
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Changes in carcass components
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Figures (9.13,14,15)
Bone- increases at a decreasing rate
Muscle is the fastest growing during early life
and post weaning, yet decreases with time
Fat is the fastest growing at physiological
maturity
A decrease in bone and muscle is due to the
extreme increase in fat percentage
Changes in chemical composition
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Protein, fat, and water
Muscle ranges from 68-85%
Moisture to protein ratio = 4:1
Decreases with age Table 9.4
 Myoglobin increases with age
 Water content of CT and adipose
tissue also
decrease with age
 Water also decreases in bone with age because of
inorganic salts deposited in modified CT to increase
bone strength
Changes in chemical composition
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CT increases with age
Accretion of collagen and elastin fibers must be
increased to form the matrix of fasciluli to form
the CT to hold the muscle bundles
Muscle fibers increase in size, yet CT decreases
in percent thus increases in size
 The
relative amount of CT in bone and fat is also
affected by the deposition of inorganic salts and lipids
Changes in chemical composition
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Nucleoproteins
 Increases
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with age yet decreases in %
Fat
 More
variable yet increases or accumulates in various
depots with age including the depots associated with
muscle
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Minerals
 Increases
with age as a general rule, yet is not true
for some ie. sodium decreases with muscle growth
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Ca, P, and K all increase with growth and with age
Factors affecting carcass
composition
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Genetics
Species
Selection and domestication
Muscle distribution
Fat distribution
Breed
Frame size
Sex
Genetics on carcass composition
Mutation or intensive selection
 Influence of environment
 Phenotype versus genotype
 Heritability estimates
 Table 9.8
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Species affect on carcass
composition
Variation between species Table 9.9
 Deposition of tissues, esp. fat
 Order of fat deposition between species
 Proportion of composition compared
anatomically
 Value differences among composition
parts of each species
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Muscle distribution
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Table 9.12 & 13
Comparison of muscle wt. distribution between
species
Ruminant versus non-ruminant and their
relationship to prehension properties
Domestic versus non-domesticated species
Meat versus milk type selection
Figure 9.26 muscle to bone ratios
Fat distribution
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Table 9.14 and Figure 9.19
Huge differences between ruminant and nonruminants
At the beginning, carcass fat is fairly even in
distribution
However, a growth increases and maturity
develops fat begins to accumulate varying
percentages at different anatomical locations
Figure 9.20 & 27
Breed variations
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Various breeds have:
 Different
maturity patterns
 Frame sizes
 Meat versus dairy type
 Selection pressure for muscling
 Figure 9.22
 Table 9.20
Frame Size
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Growth patterns
Feedlot gain and efficiency
Chronological vs Physiological maturity
Quality Grade vs fat deposition
Compositional Endpoints
Dairy vs Meat type
Dressing Percentage variations
Forage availability and utilization
Figures 9.23, 24, & 25
Tables 9.16 - 19
Sex
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Definitions
Figure 9.28, 29
Table 9.25, 26
Except for pigs, females mature earliest
Intact males have a greater proportion of muscles in the
forequarter while heifers in the proximal pelvic limb
Castrate males are intermediate
Heifers at the same physiological slaughter age and
maturity will be fatter lower yielding