Numerous trials have demonstrated the importance of good calf rearing practices on increasing 1st lactation and lifetime milk production, thus profitability. Early rumen development, gut health and integrity, and avoiding a weaning check are key factors influencing calf growth.
Highly degradable starch based feeds promote development of the rumen and its papillae. Recent trials have also shown that including specific strains of live yeast promote the proliferation of cellulolytic bacteria, important for fibre degradation, resulting in higher feed intakes at and just after weaning. The higher feed intakes are important to avoid any growth checks after weaning.
This is key where calves are expected to eat and grow from high forage intakes. Calves remain monogastrics for the first 3-4 weeks of their lives, so building the rumen should be a key consideration for any forage based system. Any growth checks experienced throughout the pre-weaning and weaning period can have significant effects on lifetime production. Creating a rumen environment with healthy papillae development and cellulolytic bacteria growth can improve forage utilisation and calves’ responses to forage intake.
Gut health and integrity are crucial in the efficient utilisation of nutrients for growth, which has led to widespread use of probiotics (beneficial bacteria) and acidifiers with very young calves, to minimise the risks of early scours associated with pathogenic bacteria such as E. coli. A more recent development has been to include antibodies against specific bacteria or viruses, e.g. rotavirus in some probiotic products. This can be especially useful with calves that may not have consumed sufficient high quality colostrum soon after birth.
Coccidiostats are generally included in milk replacers, products to fortify whole milk and calf feeds to help calves build up an immunity to avoid suffering from coccidiosis, which can seriously affect their health and growth. The Eimeria protozoal spores may be present in either or both calf rearing sheds and paddocks, so it is important to use coccidiostats before and after weaning and turn out. Trials have also demonstrated better efficacy in using the same coccidiostat in the milk or milk replacer and calf meal.
Growing healthy calves also requires good housing, environment, biosecurity, hygiene, disinfection, welfare and stockmanship, so it is important to take a holistic (whole system) approach, as the end effect is more than just the sum of all the parts. Early rumen development and good nutrition are key aspects of this approach, and help calves maximise their genetic potential.
As featured in NZ Dairy Farmer