US Dairy Production expert Mike Hutjens recently visited Australia, conducting seminars in regional Victoria organised by the Australian Association of Animal Nutrition. Some farmers may have been fortunate enough to attend one of these information filled sessions. One of the topics mentioned was accelerated calf rearing. Below is some information relating to this that may differ somewhat from our conventional calf rearing systems.
When should calves be weaned?
If you consider that 5 litres of milk (@ 40c/L =$2.00) contains roughly the same amount of Metabolisable energy (dry matter (DM) basis) as 1kg of concentrate (@ $500/t = $0.50), then it is easy to see that weaning calves off milk and onto grain is extremely cost effective. However, it is important to remember that the first 6-8 weeks will set a calf up for the rest of its life, so restricting milk intake too much could be detrimental to long term profitability.
A trial compared a conventional feeding system (4.6L milk/day) against feeding ad-lib milk (8-8.7L milk) for the first 6 weeks. The results are outlined below. The potential for higher production in the first lactation far exceeded the cost of feeding extra milk in the first 6 weeks.
Calves should be weaned when their rumen is fully developed and functional, not at a set weight or age. A calf weaned with an under-developed rumen will show a dramatic fall in growth. The best indication of rumen development is how much solid feed the calf is consuming. Calves should not be weaned until they are eating at least 1kg/day of calf starter. In a group situation intake should average 1.5kg/day before weaning to ensure that all calves in the group will be consuming enough to be weaned successfully.
How high in Protein does the calf starter need to be?
The protein source for calves as nature intended is milk. If you take into account that milk is 86-87% water (13-14% DM), then 3.0%-3.5% protein milk equates to around 23-25% protein on a DM basis. Therefore calf starter needs to be at least 20% protein to effectively act as a milk substitute. Feeding starter less than 20% protein has been found to reduce growth rate and feed efficiency in calves less than 2 months old.