A dairy calf’s milk feeding period is a golden opportunity to maximise growth. If you get it right, you will prime your growing heifers for a productive milking future when they enter the adult herd at around 24-months-of-age.
Calving heifers down at 24-months-of-age, rather than 30 months, will also help to reduce your dairy farm’s carbon footprint.
The later a heifer calves, the more feed she will consume in the rearing period, and so the more greenhouse gases (GHG) she will emit prior to milk production. Heifer rearing inefficiency increases the carbon footprint of the whole herd.
According to Una Hickey from Volac Milk Replacers Ltd., a heifer calf’s relative ability to turn nutrients into growth peaks during the early life milk feeding period, so you simply must take maximum advantage.
“During the first two months of its life, a dairy heifer calf is able turn 100g of feed into 50g of growth. That’s a feed conversion efficiency of 2:1 or 50%, but as the animal ages, this diminishes steadily, so much so that by the time a calf is 11-months-old, 100g of feed will be delivering just 8g of growth,” Hickey said.
“What’s more, research has shown that it costs less to rear a heifer from birth to 24-months-of-age when feeding 6L, rather than 4L/day of milk replacer.
“Heifers reared on 6L/day up to two-months-of age were less expensive to produce. This is because those reared on 4L/day had to grow later in life (when feed conversion efficiency is low) to reach the same body weight at first calving,” she added.
However, Una points out that environmental stress can adversely affect feed conversion efficiency: “Draughty housing and wet bedding may result in cold, sick calves that will take more energy from their feed to keep warm and fight disease, leaving less nutrition available for growth.”
Feeding the right amount of a well-mixed, proven calf milk formula is crucial when making the most of the early life feed conversion efficiency.
Both the ingredients and the volume of milk fed can affect feed efficiency; the more digestible your milk replacer, the more efficient it will be at delivering growth.
“A milk replacer’s digestibility is influenced by the type of protein and fat source used, along with its manufacturing process. Consequently, it always pays to buy a calf milk replacer from a trusted supplier.
“[E.g.,] provided your colostrum management and feeding protocol is sound – and your calves have access to fresh water, roughage and a palatable starter concentrate – we know that feeding a good heifer calf up to 900g (750g minimum) of a concentrated whey protein, Imunopro®-based calf milk replacer daily will allow you to meet optimum rearing targets.
“Indeed, these feeding levels are crucial if you want to calve heifers down with an adequate body size at 24-months,” she said.
Volac Milk Replacers Limited makes Imunopro® from liquid whey and then formulates in a balanced range of high quality nutrition and health ingredients to meet modern calf development requirements.
“The first phase is liquid blending where the Imunopro® milk complex is balanced with the necessary additional protein, oils and sugars required to allow calves to hit optimum growth and development targets when fed recommended daily amounts of milk replacer.
“The protein is balanced to ensure calves will be fed the optimum amount of true protein in the form of essential amino acids.
“It is important to appreciate that the crude protein content on the bag label does not give you an indication of the useable protein available to the calf.
“The oil is balanced with high quality vegetable fats to mimic the milk fat profile, plus the addition of butyrate (C4:0), which has been shown recently to improve gut health.
“The sugars are also balanced to ensure the final milk replacer product contains the correct energy level to meet accepted target growth rates,” she said.
She adds that the fully-balanced liquid blend is then spray dried for optimum mixability, palatability and consistency.
Finally, the addition of a proven package of health ingredients plus enhanced levels of vitamins and minerals.
