WATER-BALANCE OF SMALL LACTATING RODENTS .4. RATES OF MILK-PRODUCTION IN AUSTRALIAN RODENTS AND THE GUINEA-PIG

Rates of milk production were determined for the guinea pig and Australian rodents from a variety of habitats. Variation of growth rates of young within species show strong dependence upon milk-solid intake, whereas variation of growth rates of young between species is only weakly correlated with milk-solid intake. In the guinea pig, about 50% of the H2O secreted in milk is returned to the mother by recycling, which is important to the H2O economy of the mother. The amount of H2O recycled in the endemic rodents was not determined accurately.