Effects of sex, age, and body weight on the growth of selected organs and body parts of indigenous Nigerian pigs.

The absolute and relative growth of the head, spleen, kidney fat, stomach, and intestine were studied for 64 intact male, castrated male, and female indigenous Nigerian pigs each. Highly significant (P less than 0.001) sex, age, and sex X age interactions were obtained for the absolute and relative weights of some of the organs and body parts. The results indicate that the organ and part growth was particularly rapid between birth and 280 days of age, but stabilized beyond that time. The average growth coefficient 'b' obtained from the linearized form Y = axb of the growth equation varied between 0.819 for the head and 1.677 for the kidney fat and agreed with relevant values reported in the literature. They confirmed the sequential anterior-posterior growth pattern of organs and body parts in different anatomical regions of the body. A comparison of the allometric and quadratic models used indicated that the organ/body part growth was better described by body weight than by age.