Dairy calves are young cattle raised within the dairy industry, serving as the future milking herd. Their proper care and development from birth directly influence the productivity and longevity of the entire dairy operation, ensuring sustainable milk production and genetic improvement.
Life Stages of a Dairy Calf
Dairy calves receive significant postnatal care immediately after birth. Within hours, calves are separated from their mothers for precise monitoring of their health and nutrient intake. This early separation also helps ensure the mother’s well-being.
The first step involves feeding colostrum, the nutrient-dense first milk from the mother, which provides essential antibodies to the calf’s developing immune system. Calves are housed individually in calf hutches for their first six to eight weeks, offering protection from illness and injury while allowing farmers to monitor individual feed consumption. These hutches provide a clean, dry, and well-ventilated space, allowing the calf to stretch and lie down comfortably.
The transition from liquid to solid feed, known as weaning, occurs when calves are between six to ten weeks old, provided they are consuming enough solid feed. Following weaning, calves are moved into group pens, where they continue to grow into heifers. These young females are then bred around their yearling stage, aiming for their first calving at approximately two years of age, at which point they join the milking herd.
Nutritional Needs and Feeding Practices
The nutritional program for dairy calves begins with colostrum, rich in proteins, vitamins, and minerals like copper, iron, magnesium, and manganese. Calves should receive high-quality colostrum, at least 3 to 4 liters, within the first 1 to 6 hours after birth to ensure adequate absorption of immunoglobulins for disease resistance. Delaying this feeding can reduce the calf’s ability to absorb these protective antibodies.
After the initial colostrum period, calves are fed either whole milk or milk replacers. Milk replacers are chosen for their cost-effectiveness and are formulated to provide necessary nutrients for growth and health. Calves receive milk or milk replacer at a rate of 10-20% of their body weight daily, in two or three feedings, adjusted for factors like desired daily weight gain, calf health, and environmental conditions.
Calf starter feed, a dry grain mixture, is introduced early, by day four, to encourage rumen development. This feed stimulates the growth of rumen papillae, which are necessary for the calf to digest solid feeds efficiently. Fresh, clean water should always be available, as it is important for rumen development and overall hydration, even with liquid feed. Forage, such as hay, is introduced closer to weaning or after the rumen is fully functional.
Ensuring Calf Health and Welfare
Maintaining calf health involves proactive measures against common challenges like scours (diarrhea) and respiratory diseases. Preventative strategies include colostrum management and consistent vaccination programs tailored to specific farm needs. Ensuring calves achieve adequate serum total protein levels, above 5.1 g/dL, indicates successful passive transfer of immunity.
Hygiene and proper housing conditions are also important for preventing illness. Cleanliness of bedding, provision of dry and well-drained areas, and adequate ventilation are important to minimize disease spread. Housing systems, whether individual hutches or group pens, should offer enough space for calves to move freely, with a recommended minimum of 2.3 to 2.8 square meters per calf in group housing.
Calf welfare extends to humane handling and environmental comfort. This includes providing protection from extreme temperatures, with consideration for calf jackets in cold weather and proper airflow in hot conditions. Practices like disbudding, which is the removal of horn buds, are performed at 2-6 weeks of age with local anesthesia and anti-inflammatories to manage pain.