1. WHOLE BODY ANIMAL GROWTH ANSC 590 ANIMAL GROWTH AND DEVELOPMENT

2. GROWTH CURVES Represents an increase in size relative to a period of time (figure 9.1) Often impacted on compositional levels of varying tissues ie. Muscle, fat, bone, CT Dependent on plane of nutrition and stage of development Four phases of growth (figure 9.5)

3. AGE and MATURITY Chronological versus physiological Maturity is the point in time when an animal reaches its highest level of complexity or development Absolute growth rate: utilizes units  ADG, WDA, Birth, Weaning, etc. (Figure 9.9)  Growth rates of various tissues (figure 9.11)

4. Changes in Body Measurements Quantifiable Carcass length in pork – value  Standard reference points of measurement LEA/REA (LD muscle)- cross section FT (SubQ) – where is the best place to measure????? Body weight measures (table 9.2)

5. Body Measures Empty body wt.  Withhold feed and water for 24 hours prior to slaughter to secure shrunken weights  Research methods: withhold feed for 12-24 hrs. prior to weighing if conducting research  Pasture gain test Conduct a pre and post weight (shrunk wt. if less than 90 day trial)

6. Dressing percent Removal of everything but the carcass Factors that affect DP: fill, muscle, fat, hide, etc. Assessment of value in the animal industry Table 9.3

7. Changes in carcass components Figures (9.13,14,15) Bone- increases at a decreasing rate Muscle is the fastest growing during early life and post weaning, yet decreases with time Fat is the fastest growing at physiological maturity A decrease in bone and muscle is due to the extreme increase in fat percentage

8. Changes in chemical composition Protein, fat, and water Muscle ranges from 68-85% Moisture to protein ratio = 4:1 Decreases with age Table 9.4  Myoglobin increases with age  Water content of CT and adipose tissue also decrease with age  Water also decreases in bone with age because of inorganic salts deposited in modified CT to increase bone strength

9. Changes in chemical composition CT increases with age Accretion of collagen and elastin fibers must be increased to form the matrix of fasciluli to form the CT to hold the muscle bundles Muscle fibers increase in size, yet CT decreases in percent thus increases in size  The relative amount of CT in bone and fat is also affected by the deposition of inorganic salts and lipids

10. Changes in chemical composition Nucleoproteins  Increases with age yet decreases in % Fat  More variable yet increases or accumulates in various depots with age including the depots associated with muscle Minerals  Increases with age as a general rule, yet is not true for some ie. sodium decreases with muscle growth Ca, P, and K all increase with growth and with age

11. Factors affecting carcass composition Genetics Species Selection and domestication Muscle distribution Fat distribution Breed Frame size Sex

12. Genetics on carcass composition Mutation or intensive selection Influence of environment Phenotype versus genotype Heritability estimates Table 9.8

13. Species affect on carcass composition Variation between species Table 9.9 Deposition of tissues, esp. fat Order of fat deposition between species Proportion of composition compared anatomically Value differences among composition parts of each species

14. Muscle distribution Table 9.12 & 13 Comparison of muscle wt. distribution between species Ruminant versus non-ruminant and their relationship to prehension properties Domestic versus non-domesticated species Meat versus milk type selection Figure 9.26 muscle to bone ratios

15. Fat distribution Table 9.14 and Figure 9.19 Huge differences between ruminant and non- ruminants At the beginning, carcass fat is fairly even in distribution However, a growth increases and maturity develops fat begins to accumulate varying percentages at different anatomical locations Figure 9.20 & 27

16. Breed variations Various breeds have:  Different maturity patterns  Frame sizes  Meat versus dairy type  Selection pressure for muscling  Figure 9.22  Table 9.20

17. Frame Size Growth patterns Feedlot gain and efficiency Chronological vs Physiological maturity Quality Grade vs fat deposition Compositional Endpoints Dairy vs Meat type Dressing Percentage variations Forage availability and utilization Figures 9.23, 24, & 25 Tables 9.16 - 19

18. Sex Definitions Figure 9.28, 29 Table 9.25, 26 Except for pigs, females mature earliest Intact males have a greater proportion of muscles in the forequarter while heifers in the proximal pelvic limb Castrate males are intermediate Heifers at the same physiological slaughter age and maturity will be fatter lower yielding