Growth and Development – Composition An S 426 Spring 2007

1. Growth and Development – CompositionAn S 426 Spring 2007

2. Growth and Development – Composition • Function of genotype and environment • Cattle have 30 pairs of chromosomes • Sex determines the development and function of the organs and glands Example: • Glands produce hormones which cause certain things to occur in the body – some seen and others unseen Examples:

3. Growth and Development – Composition Sigmoid prenatal and postnatal growth patterns

4. Growth and Development – Composition • Four segments of growth curve (i.e. postnatal) 1. 2. 3. 4. • Compensatory gain Why important:

5. Impacts of frame size –

6. Impacts of frame size –

7. Impacts of frame size –

8. Growth and Development – Composition • Results: 1. Later maturity of large framed cattle Period 1 – no difference between types for ADG and F/G Period 2 – small framed cattle gained slower and were less efficient Period 3 – large framed cattle became less efficient 2. Large type cattle had higher DFI and ADG (P < 0.01) • F/G over total feeding period nearly the same

9. Growth and Development – Composition • Results: 3. Implants improved ADG (P < 0.01); 44 lb. in large and 70 lb in small framed cattle • F/G was improved + 13.3% in small type cattle, but no difference in large type cattle

10. Growth and Development – Composition • Results: 4. Large frame cattle had less BF and larger LEA; when adjusted for carcass weight, small type had larger LEA (P < 0.01) 5. Small framed cattle appear to respond more to implants than large framed cattle

11. Growth and Development – Composition • Endocrinology – Interrelationships of small, medium and large frame cattle and estradiol implants Study: Assumptions: 1. 2.

12. Growth and Development – Composition

13. Growth and Development – Composition

14. Growth and Development – Composition • Results: 1. Small frame, earlier maturing cattle, had higher concentrations of insulin (P < 0.05) and lower concentrations of GH 2. Large frame, later maturing cattle, had higher concentrations of GH (P < 0.10) and lower concentrations of insulin 3. Within each cattle type, implanted cattle had higher concentrations of GH

15. Growth and Development – Composition • Results: 4. Thus, higher insulin concentrations in small, early maturity types of cattle may explain earlier fat deposition Whereas, the greater concentrations of GH in large, later maturing types of cattle may account for the greater growth rate and later fat deposition

16. Growth and Development – Composition • Concepts of growth and development • Deposition of tissues: 1st 2nd 3rd 4th

17. Growth and Development – Composition • Concepts of growth and development • Muscle and fat development Number of cells determined early in prenatal period • To increase muscle, need to select for more cells • To increase fat, increase fat cell size fat distribution in carcass: • Subcutaneous = • Intermuscular = • Intramuscular = • Internal =

18. Growth and Development – Composition • Concepts of growth and development • Schematic:

19. Growth and Development – Composition • Concepts of growth and development GHRF – Synthetic estrogens (implants)