Important Growth Concepts for Animal Production. Luis Nabté-Solís

Outline 1. Introduction 2. Growth Concepts 3. Factors affecting growth 4. Conclusions

Introduction Growth  new cells. (increase in mass, not water increase)Growth  new cells. (increase in mass, not water increase) Not only cell multiplication (hyperplasia), also cell enlargement (hypertrophy)Not only cell multiplication (hyperplasia), also cell enlargement (hypertrophy) By definition, growth includes deposition of fat even though muscle mass is of primary interest in meat production.By definition, growth includes deposition of fat even though muscle mass is of primary interest in meat production. Mature size generally is considered the point at which muscle mass reaches a maximum.Mature size generally is considered the point at which muscle mass reaches a maximum.

ME = NE g + NE l + NE y + NE m + H i E NE g energy content of the tissue deposited (Berg and Butterfield, 1976)

Growth curves and tissues growth rate (Owens et al., 1993)

(Berg and Butterfield, 1976)

Body Composition

Owens, et al., 1995

(Owens et al., 1993)

Effect of feeding level on Body Composition (Diaz et al., 2001)

Problem Review… (Diaz et al. 2001),

Breed Effect on Body Composition and Growth Jenkins and Ferrel, 1997

(Berg and Butterfield, 1976)

Goats Breeds and Crossbreeds and economical assessment (Pineda et al., 1998)

Conclusions Growth is a critical period in the animal production Body composition is mainly determined by the stage of growth, breed, sex, and age Body composition can explain in some extent differences in maintenance requirements differences between breeds Growth and Body Composition studies can help to choose the more adequate breed for specific conditions Nutrient supply can alter body composition of neonatal ruminants