Developmental changes in composition of cats' milk: Trace elements, minerals, protein carbohydrate and fat

The concentrations of iron, copper, zinc, manganese, calcium, magnesium, protein, carbohydrate and fat were analyzed in cats' milk during the course of lactation. Cats' milk is different from most species in that the concentrations of iron, copper, zinc and manganese are lower during the first 2 days of lactation than on days 3-7. After the initial rise in the concentration of these elements, the concentration of iron decreased from 5.9 μg/ml to 3.0 μg/ml, with most of the decrease occurring between day 8 and 21. Copper concentration declined from 1.6 μg/ml to 0.8 μg/ml, with most of the change occurring between days 8 and 28. Concentration of manganese increased during lactation, from 0.14 μg/ml to 0.39 μg/ml. Calcium concentration increased rapidly during the first 3 weeks from 550 μg/ml to 1500 μg/ml, with little change thereafter. The magnesium concentration (≃100 μg/ml) and zinc concentration (≃6 μg/ml) were not affected by stage of lactation. Protein increased during lactation from 4% to 7%, and fat from 3% to 5%, whereas carbohydrate concentration (≃4%) did not change significantly. These data demonstrate that the nutrient intake of the kitten changes markedly during the early neonatal period and that these changes should be taken into account in evaluating studies of suckling cats.