1. Growth and Development
Dr. Randy Harp

2. Growth: Growth is an increase in mass True Growth?? Tissues Bone
Internal organs
Muscle
Fat
True Growth??

3. Growth: Growth is an increase in mass True Growth?
Tissues
Bone
Internal organs
Muscle
Fat
True Growth?
Everything except Fat

4. Normal Postnatal Growth Curves of Bone, Muscle, and Fata
Maturity
Muscle
Growth
Units
Fat
Birth
Bone
Time Units
a Adapted from Boggs, et al, 1998

5. Normal Growth Curve of Cattlea
Units
Time Units
a Adapted from Berg & Butterfield, 1976
Birth
Maturity
1400 lbs
1100 lbs
900 lbs

7. Age:
Physiological Age
Chronological Age

8. Age: Physiological Age Development of the animal relative to maturity
Chronological Age
Actual Age in days

9. Fat Tissue Depots: Subcutaneous Fat Internal Fat Intermuscular Fat
Intramuscular Fat

10. Fat Tissue Depots: (order)
Subcutaneous Fat ~ Backfat (3rd)
Internal Fat ~ KPH (1st)
Intermuscular Fat ~ Seam fat (2nd)
Intramuscular Fat ~ Marbling (4th)

11. Normal Postnatal Growth Curves of Bone, Muscle, and Fata
Maturity
Marbling
Muscle
Growth
Units
Fat
Birth
Bone
Time Units
a Adapted from Boggs, et al, 1998

12. Visual Indicators of Finish

13. Visual Indicators of Finish

14. Visual Indicators of Finish
BF 1.50
REA 10.6
YG 6.0 BF
REA 13.5
YG 3.3

15. Visual Indicators of Finish

16. Types of Growth: Hyperplasia Hypertrophy Increase in cell number
Occurs during Prenatal growth
Research indicates that cell number is set
Hypertrophy
Increase in cell size after birth

17. Benefits to altering growth:
Increase in the amount of product to sell
Change composition of saleable product

18. Methods to alter growth:
Natural
A) Genetics
British vs European/Continental Breeds
British ~ “Maternal”
Earlier rate of maturity
Less muscle more fat
Continental ~ “Growth and Carcass” “Terminal”
Later rate of maturity
More muscle less fat
F1 Progeny
Heterosis

19. Factors Affecting Growth:
Natural
B) Nutrition:
1. Types of growing/finishing cattle
a. Grass Cattle - growing
b. Finishing- growing/fattening

20. Methods to alter growth:
Adminstered ~ Growth Promoting Agents
A) Implants
- Made of naturally occurring hormones
- Estrogen, Progesterone
Ralgro, Synovex, etc.
- Synthetics Trenbolone Acetate (TBA)

21. What Implants do: Improved Feed Efficiency
Increased Average Daily Gain
Increased Dry Matter Intake
Increase in Body Mass

22. What Implants do: Improved Feed Efficiency 15%
Increased Average Daily Gain 10%
Increased Dry Matter Intake 5-10%
Increase in Body Mass %
Efficiencies and increase in wt gain can result in
dollars advantage over non-implanted

23. Methods to alter growth:
Administered ~ Growth Promoting Agents
A) Implants
B) Beta Agonists

24. Beta Agonists: Ractopamine HCl - Cattle ~ Optaflex
Fed last days 100 – 300 mg / day
Improvement: ) Performance
F/G, ADG same DMI
2) Dressing Percent
3) Carcass wt
4) No adverse affect on Marbling ) Tenderness affected at 300 mg
Zilpaterol HCl –
6.8 g/ton to provide mg/hd/day
Fed as Showmaxx via layman OR
Fed in feedlots in concentrate form supervised by a DVM