PP33 Equine Growth and Development

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PP33Equine Growth and Development

• ANS 3043
• University of Florida
• Dr. Michael J. Fields

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Breed Differences in Birth Weights as Percentages
of Adult Weights
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Percent of Adult Weight Achieved During Growth by
Different Breeds
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Percent of Adult Height Achieved During Growth by
Different Breeds
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Relationship of Wither and Hip Height Growth in
Thoroughbred Foals to 20 Months
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Sex and Weight Relationships in Young
Thoroughbreds First Year of Life
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Sex and Weight Relationships in Young
Thoroughbreds in Second Year of Life
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Height and Girth Measurement Relationships in
Thoroughbreds from Birth to One Year
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Cannon Circumferences of Growing Thoroughbred
Colts and Fillies
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Effects of Weaning Age on Growth
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Rate of Growth in Thoroughbreds After Birth to 18
Months of Age
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Equine Anatomy
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Equine Foreleg Anatomy
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Equine Foreleg AnatomyCarpus and Metacarpus
Proximal
Distal
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Equine Foreleg Anatomy
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Comparing Percent Ossification of Limb Bones in
Premature vs. Term Foals
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Bones Contributing to Growth in Height of the
Horse
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Long Bone Anatomy
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Epiphyseal Plate Anatomy
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Rate of Radial Bone Growth from Each Physis in
Horses
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Ratio of Proximal to Distal Physis Growth in
Horses
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Number of Growth Plates in the Foreleg and
Relation to Height Increase in Growing Horses
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Growth of Proximal and Distal Ends of the Radius
in Several Species
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Dorsal-Palmar View of Equine Foreleg
26 weeks old
One day old
3rd Metacarpal
The indicates the open and fused
physis of each bone at one day old and 26 weeks
old, respectively.
1st Phalanx
2nd Phanlanx
3rd Phanlanx
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Lateral-Medial View of Equine Foreleg
26 weeks old
One day old
3rd Metacarpal
3rd Metacarpal
The indicates the open and fused
physes of each bone at one day old and 26 weeks
old, respectively.
1st Phalanx
1st Phalanx
2nd Phanlanx
3rd Phanlanx
2nd Phanlanx
3rd Phanlanx
(Smallwood et al., 1973)
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Epiphyseal Closure of Equine Forelimbs
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Epiphyseal Closure of Equine Forelimbs
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Percent of Horses With Distal Radius Epiphyseal
Closure According to Age
Mason et al., 1973
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Mineral Composition of the Whole Body of Young
Horses
1 of empty BW 2 mg/g of fat-free dry tissue 3
mg/kg of fat-free dry tissue
a,b,c,d Values with unlike superscripts are
significantly different at 1 (a, b) or 5 (c,d)
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Ash Content and Failure Stress of Equine
Metacarpal Bone in Relation to Age
(El Shorafa et al., 1979)
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Bone Mineral Content of Equine Third Metacarpals
and Age
Bone mineral content does not peak until 6 yrs
old
r2 .92
(Lawrence et al., 1994)
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Managing Growth in the Equine

• Promote a moderate and steady growth rate, which
  will be dependent on mature size
• Extremely rapid growth caused by overfeeding of
  energy may be cause of developmental orthopedic
  disorders (DOD) and unsoundness
• Cartilage invasion of joints
• Wobbler syndrome (cervical vertebral column
  malformation)
• Bone cysts in areas of high compression
• Enlargement of epiphysis
• Angular limb deformities
• Cuboidal bone malformation

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Managing Growth in the Equine

• Decreased growth followed by rapid growth can
  also lead to DOD
• Imbalanced Calcium, Phosphorous and trace
  minerals have also been linked to DOD
• Forced exercise can lead to DOD

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Managing Growth in the Equine

• Diets should contain adequate, but never excess
  energy
• Feed a supplement in horses are also on pasture
• Excess energy maybe most common cause of DOD
• Know and understand where horse is on growth
  curve and adjust diets accordingly
• Adequate energy to protein ratios are essential
• Diets low in portein or a decreased energy to
  protein ratio can result in failure of horse to
  reach mature height and decreased bone mineral
  content

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Managing Growth in the Equine

• Calcium and Phosphorous ratios should be
  maintained between 11 and 31
• Maintain adequate intake of trace minerals
• Calcium, Phosphorous, Copper, Zinc, Manganese,
  Magnesium, Selenium

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Managing Growth in the Equine

• Provide opportunity for ample exercise
• Bone responds to exercise although it must be
  managed closely and combined with a proper
  nutritional program
• Bone will not grow and remodel if animal is
  inactive