The following review questions are intended to point out
 out and help you understand some of the major points in
 the recommended reading material in Scientific Farm Animal
 Production (8th Ed.) by R. E. Taylor and T. G. Field.
     
CHAPTER 18:  Growth and Development
    
In class we discussed bone growth, muscle growth and development, 
and fat (adipose cell) development as they relate to body composition, 
feed efficiency, and daily gain of farm animals.  We discussed only 
a portion of the material covered in Chapter 18.

In the text, review the pages in the latter half of the chapter 
beginning with "Growth Curves" and the figures associated with
those pages.  The following headings are included:

     GROWTH CURVES
     CARCASS COMPOSITION
          Effects of Frame Size
          Effect of Sex
          Effect of Muscling

The following questions are taken primarily from your notes; the text 
will be helpful for the growth curves and carcass composition questions.

      
CHAPTER 18:  Growth and Development
    
 18-1. What is the definition of growth?  Why can't it be
       defined simply as gain in weight?  Can fat deposition
       be included in the definition of true growth?
    
 18-2. Give the composition (percent muscle, fat, and bone)
       of a typical yield grade 3, Choice steer.  Compare
       this to the composition of the YG 5 steer shown in the
       color plate section of your text.  What components
       changed the most between a YG 3 and a YG 5 steer? 
       Which changed the least?

 18-3. In what two ways does growth occur?  When does
       hyperplasia occur for most types of cells/tissues in
       the body?  When does hypertrophy occur?

 18-4. How do bones grow in length?  How do they increase in
       diameter?  You need to mention changes in the marrow
       cavity when describing changes in bone diameter.

 18-5. What is the "break joint" vs. the "spool joint" in
       determining whether a sheep is lamb or mutton?

 18-6. How do we use our knowledge of bone growth to
       determine the "maturity" of a carcass when determining
       beef quality grades?
    
 18-7. What two factors (or measurements) are used to
       determine frame size in cattle?  
    
       Why is height at the hips used for frame size rather
       than some other measurement?
    
       Why is frame size important to know when purchasing
       immature cattle such as a young herd sire?
    
 18-8. What are adipose cells?  When an animal grows, does
       fattening occur by hyperplasia or hypertrophy of
       adipose cells.
    
 18-9. We discussed four areas or sites that fat is deposited
       as an animal grows and accumulates body fat.  What are
       these four sites and in what general order does
       fattening occur among these sites?
    
18-10. Of the four sites in 18-9, which contains the largest
       quantity of fat in hogs?  Which is largest in beef?
    
18-11. There are three layers of subcutaneous fat in hogs? 
       Which are affected most when we select for decreased
       backfat thickness?  Which is affected least?
    
18-12. Describe how subcutaneous fat deposition occurs on
       cattle.  What/where are the initial sites and how does
       fat deposition spread from those sites.
    
18-13. One of the sites of fat deposition is important in
       determining quality grades for beef.  Give two names
       used for this site.  What is fat at this site an
       indicator of in terms of "eating quality" of beef?
    
18-14. What measurements can we make on live animals to help
       us know when to market them so 60-70% of them will
       grade Choice with having too many that will be YG 4? 
       Specifically, where are these measurements made?
    
18-15. What is the relationship between the sex of an animal
       and fat deposition (or leanness)?  The text also
       discusses this.
    
18-16. Discuss the relationships between muscle location,
       contraction, connective tissue, and meat tenderness. 
       Where does the more tender meat tend to come from on
       the carcass?  The least tender?  What are some of the
       reasons for the differences in tenderness?  How does
       tenderness relate to age of the animal?
    
18-17. What is meant by "aging" of meat?
    
18-18. GROWTH CURVES.  You should be able to draw
       representative growth curves for cattle or swine three
       ways:
    
       1) A single sigmoidal curve representing change in
          weight as an animal gets older.  You should be
          able to identify points on that line where gains
          are the most rapid, feed efficiency is best,
          muscle growth begins to slow, and fat deposition
          begins to accelerate.
    
       2) Three lines representing the growth (increased
          weight) of bone, muscle, and fat as an animal
          grows from birth to market weight.
    
       3) Three lines representing the growth of bone,
          muscle, and fat as a PERCENTAGE of the total
          weight gain of the animal at different ages or
          weights.  We did this in class for hogs.  For
          example, for a 50-lb. feeder pig, bone accounted
          for 12% of the gain, fat 28%, and muscle 60%.  You
          don't need to know the specific numbers, but you
          should understand the general relationship of the
          three curves.
    
       Your text has a good discussion of growth curves and
       carcass composition.
    
18-19. What happens to percent water in the body as an animal
       gets fatter.  Why does this change occur?

18-20. What is the calorie content of a gram of fat, protein,
       and carbohydrate?  This refers to a gram of actual
       fat, protein, or carbohydrate....no water.  (Remember,
       even though we say "calories" they actually are
       "kilocalories" (kcal).)  Using this knowledge of
       calorie content of a gram of fat, protein or
       carbohydrate, you can look at the label of a food and
       calculate the number of kcal in a serving.  Your
       calculated number of kcal should be very close to the
       calories listed on the label.  Have you tried this?
    
18-21. As an animal gets fatter, feed efficiency gets worse,
       and daily gain gets slower.  Give two reasons that
       feed efficiency gets worse.  (It may be helpful to
       review the concepts you learned in questions 19 and 20
       above.)  Why does daily gain get slower?
    
18-22. We looked at slides similar to Fig. 18.16 in your text
       and discussed the effects of frame size on carcass
       composition.  How should we compare the performance,
       efficiency, and carcass composition (percent muscle
       and fat) of animals having different frame sizes?  Is
       it reasonable to say that larger-framed cattle are
       leaner than smaller-framed animals?