Calf transition: managing and feeding the calf through weaning

In recent years, the industry has progressively provided greater milk allowances to young calves in an attempt to improve growth performance and health, and foster the expression of the full milk potential. However, these feeding programs have challenged the ability of the calf to transition from a liquid to a solid diet. Increased supply of milk in combination with a gradual weaning scheme can promote greater growth, reduce hunger distress, and improve feed efficiency in calves; but an adequate intake (~2 kg/d) of pelleted or texturized calf starter feed at weaning is necessary for calves to smoothly transition maintaining gains >1.2 kg/d, which should minimize health disorders and optimize rearing costs. The ideal feeding management of calves would consist of feeding either pelleted starter feeds along with some poor quality (in terms of nutrient content) chopped grass forage, or well formulated texturized starter feeds that provide sufficient abrasive action in the rumen. A successful transition depends, among other factors, on an adequate rumen development, which is not only affected by the amount and type of solid feed consumed but also by the nutrients supplied from liquid feed, the weaning method imposed, the solid feed program, and the social management of the calves. Milk allowance should be progressively reduced before weaning to ensure that sufficient amounts of solid feed are consumed by calves to continue support growth. However, these weaning methods may be difficult to implement in small herds, and under those circumstances a more practical approach consists of reducing milk allowance in two phases, first reducing the amount of milk at each milk feeding, and then reducing the number of milk offers. Weaning in groups (and raising calves in groups long before weaning) fosters solid feed intake, and this should ease transition and minimize cross-suckling behavior (as calves are more likely to cover their energy needs form solid feed). Feed sorting develops early in life, and calves at that stage may select, provided the chance, in favor of components with high-energy density or those that a more preferred to calves. Ideally, the transition ration should provide some amount of forage to ensure adequate abrasive activity, rumen motility, and passage rate, along with sufficient amounts of starch to sustain growth.