Which milk source is best for your calves? The calculator below facilitates a simple comparison on cost, energy and protein value. It provides a quick comparison between whole milk and up to two CMR’s.
Many CMRs are more cost-effective than feeding saleable milk from the tank. This is especially true when we factor in the risks of Johne’s disease and the possibility that whole milk from the cow isn’t necessarily designed for the modern calf!
Milk yields per cow have changed a lot, yet often calf rearing practices have changed little. Is it time for a rethink?
When using the calculator it is worth concidering the potential dry matter intake that is achievable for a given weight. DMI from CMR is typically around 2% of the calf’s liveweight in the first week, rising to 2.25% thereafter (i.e. as 45kg calf would be around 900g). Ad-lib calves >65Kg are closer to 2.5% of LW*.
As shown by the work of de Passille**, illustrated in the chart, intakes can be variable across and within liveweights. Management, hygiene, environment as well as nutrition all play a part in intakes.
For whole milk from the farm; the calculator works best if you use your own milk composition. It’s worth taking a moment to concider the variability of fat and protein in the whole milk from your tank or taken from a number of individual cows. The variability can be huge from day to day and even AM to PM. Nutritionally this isn’t ideal.
Ultimately, over the pre-weaning period, it will be the combined nutrition of colostrum, milk, and starter that will determine growth to weaning. Ensuring that the total nutrition of the calf is met is the single most important factor to deliver value.
The choice of skim v whey is also a factor. You may value a skim above a whey if you require clotting for more sustained digestion. However, little difference in performance has been reported where effective starter feeds are offered in combination.
A further, yet important, variable should be considered when choosing a starter. Some CMRs have added features that can assist the development of the calf and could lead to better first and subsequent lactation performance. While not a straightforward calculation, it is worth factoring in the value you place on the chosen CMR.
The calculator below is a useful base guide when selecting, but creating a full calf nutrition plan; including starter, forage offered, management and environment will provide a much fuller picture.