Factors influencing growth of rumen, liver, and other organs in kids weaned from milk replacers to solid foods.

From pooled data of many feeding trials with kids fed various types of solid foods from 37 days of age and slaughtered thereafter, relationships between such independent variables as age, cumulative intake of solid food, weight gain, and/or final body weight and such dependent variables as weights and such dependent variables as weights of stomach-compartments, heart, liver, kidneys, and spleen were analyzed. Growth of forestomachs, and especially rumen mucosa, relative to body weight was stimulated only in feeding periods of solid foods. Gain, intake of solid food, and final body weight were the best predictors for growth of forestomach-compartments, liver, and heart, respectively. Correlations were large between ruminoreticulum weight and liver weight and among weights of forestomach-compartments. Second degree polynomials were fitted to predict the curvilinear relationships between solid-food intake and either ruminoreticulum weight or rumen mucosal weight, and a linear equation was fitted to predict the relationship between solid-food intake and liver weight. Feeding of roughage increased rumen muscular and omasal weights. Growth of the rumen under stimulation of solid-food intake may be regulated by the same biological factors contributing to increased growth rate of the whole animal. In this situation, growth of the rumen may be correlated closely with growth of the liver.