Grober Nutrition

inter-feeding in cold climatic conditions requires additional attention to ensure that the young calf is provided with sufficient nutrients for maintenance and for growth expectations.

The young calf has limited reserves of energy and when exposed to temperatures below the lower critical temperature for extended periods of time, these reserves are quickly depleted. For example a day old calf has about 500g of fat and 180g of glycogen that it can mobilize and metabolize for energy sources. These reserves of energy would be exhausted in approximately 18 hours (Okamoto et al, 1986).

Researchers (1985) have shown weight gains were highest for calves fed additional solids and were greater with more feedings per day. This was in comparison to adding a whey fat blend to the ration.

The table below illustrates the effect of reducing temperatures on energy retention by the young calf and the amount of Excel milk replacer (ME: 4.33 Mcal/kg DM) required to maintain energy balance.

(adapted from Schrama et al, 1993) *calculations based on extra heat production value of 2.15 kcal/kg0.75 per day per °C below critical temperature.

This clearly shows that the energy requirement of the young calf is dramatically increased when the environmental temperature falls below its critical temperature. If target growth rates are to be maintained then producers must feed their calves extra energy during winter months.

Ways to help the young calf under conditions of cold stress are:

• Ensure that the calf has access to dry, well-bedded shelter that provides protection from wind and is free from drafts.

• Provide extra energy through its feed by increasing the amount of milk or milk replacer being fed. (see related table for Excel/ High Performance and VG milk replacer)

• Observe the weather forecast so that changes can be introduced gradually.

• Calves with a negative energy balance will use brown fat stores available to generate heat to maintain core body temperature. This is not efficient and will affect the health status and immune function of the young calf.

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