Feb 24, 2016 · Weaners (3 to 15 months): The protein content in the feed after weaning to 1 yr should be 16%, and from to 1 year to 16 months should be 14% CP. During this stage of heifer rearing, avoid overfeeding with concentrates because over conditioned heifers produce less milk in their later life than those reared in moderate level of nutrition.