1. Evaluating Fat and Muscle in Livestock
Developed by:
Celina Johnson
University of Florida

2. Why is it Important to Evaluate Fat and Muscle?
Meat Animals - we sell muscle
All gender classes - important
Intact males, market animals and replacement females.
Johnson, 1997

3. How Do Animals Get Fat?
Top to Bottom
Front to Rear
Johnson, 1997

4. Growth Curve 4 3 2 1 1. Prenatal 2. Rapid Growth 3. Fat deposit begins
Time
Wt.
market 2
puberty
1. Prenatal
2. Rapid Growth
3. Fat deposit begins
4. Fat 1
Johnson, 1997

5. Female usually deposits fat earlier than castrates or intact males.
Effects of Sex
Female usually deposits fat earlier than castrates or intact males.
Cattle: Heifers market at lighter wts.
Exception: Swine
boar gilt barrow
lean fat
Johnson, 1997

6. Effects of Frame Size Small Framed animals:
Greater deposit of fat at lighter weights
At the same body composition, small animals will be lighter.
Johnson, 1997

7. At Equal Body Composition:
Weights: Lg > Med > Small
Efficiency: Equal, same point on growth curve
At Equal Weight:
Efficiency: Lg > Med > Small
why? Composition
Johnson, 1997

8. Effects of Frame Size Age Influences Large Medium Weight Small Age
Johnson, 1997

9. Effects of Frame Size Weight Influences Large Medium Weight Small Age
Johnson, 1997

10. Fat Deposition Sites Brisket (cattle), Jowl (hogs), Breast (lambs)
Ribs
Loin Edge
Twist Area
Flank
Tailhead area
Johnson, 1997

11. Fat Deposition Sites
Johnson, 1997

12. Muscle Evaluation Sites
Hindquarter (round - cattle; leg - lamb; ham - hog)
Stifle
Forearm
Over Top - loin and rump
Width of Base
Johnson, 1997

13. Muscle Evaluation Sites
Johnson, 1997

14. Muscle Evaluation Sites
Johnson, 1997

15. Body Shapes
The widest part of the animal should be at the stifle, indicating lean, not fat
Desirable
Undesirable
Johnson, 1997

16. Lean Hog
Johnson, 1997

17. Over Finished Hog
Johnson, 1997

18. Under Finished Beef
Johnson, 1997

19. Over Finished Beef
Johnson, 1997