For decades, many farms have been feeding 4 or 5 litres per day of whole milk or calf milk replacer (CMR). Those same farms can also share their stories of disease or bacteria outbreaks within their calf sheds. Expensive vaccination programs, no end of sleepless nights, and obsession with a particular virus or bacteria have followed this.
At the ProviCo Rural Calf Health Forum in Melbourne in March, calf health expert Sam Barringer said this was focusing on the bullet, not on the gun or who pulled the trigger.
While not wanting to downplay the importance of identifying the particular bug, Dr Barringer suggests the real focus should be on what circumstances allowed that situation to occur and why the bug overcame the calf's natural health defences.
Although cleanliness and hygiene are crucial, inadequate nutrition is almost always the primary issue.
The importance of colostrum, especially the first colostrum, is widely known, and the sooner this is delivered, the better. Use a brix meter, understand what you've got, and if you don't have enough high-quality colostrum, use a colostrum supplement.
Now, let's return to those calves feeding only 4 or 5 litres daily.
If a calf remained feeding on the cow, it would receive between 8-10 feeds per day, roughly 1 litre per feed. Assuming 125g of solids (fat, protein, and lactose) per 1 litre of whole milk, the calf would consume almost 1kg of milk solids per day. When you compare that with the calf in the rearing program, which consumes 4 litres/day, that equates to 500g grams of milk solids the calf receives. Also, young calves aren't yet eating any starter muesli at this age. We are underfeeding calves from the get-go!
It's that underfeeding that opens the door to disease.
So, feeding more solids is a key component of the solution — animals on a better nutritional plan typically have greater health.
So, how much do calves need?
There is no simple answer, as temperature and environment also play a role. Broadly speaking, between 1.5 and 2 per cent of body weight as milk solids is a good guide.
Think of it a little like the cows. We feed them in kilos of dry matter — it's the same with calves. We need to think in terms of their DM intake, even though we deliver it as a liquid: 1 litre of milk equals 125g DMI, so 4 litres of milk/day equals 500g DMI/day.
We have all the tools at our disposal — milk, water, calf milk powder, and the number of feeds per day. All we need to do is manipulate each of these tools to optimise the nutrition we offer our calves.
Adding milk powders to whole milk increases the level of nutrition per litre, so we can feed fewer total litres but provide more solids to the calf and sell more milk.
The tool we use to aid us in this milk math is the NRC Calculator. It's a free phone app available from most app stores and helps you run different scenarios to see which one gives the best outcome.
Some rules of thumb
Rules of thumb are dangerous because they can be broken without consequence. However, we should keep them in mind regardless, as sooner or later, we get bitten.
Whole milk is about 12.5 per cent solids (125g/litre). Milk powders are 1g of powder equals 1g of solids. Keep your final milk solution below 16 per cent solids (use water to dilute if needed), ideally below 15 per cent.
The maximum suggested DMI for Holsteins is 1.1kg/day and for Jerseys is 0.9kg/day. Try to get the milk mix protein above the fat.
Using powders with whole milk is called ‘fortifying milk’, a practice used globally. Fortifying with the right powder can significantly improve calf outcomes.
Which powder?
Nothing is as good as whole milk; that's why milk processors pay us for it. However, we must consider the other significant change we have imposed on the calf.
Off its mother, it would get that high-fat milk in 8-plus feeds over the whole day. We are trying to squeeze all of that nutrition into two feeds.
Those two big feeds of high-fat whole milk take time for the young calf to digest and, importantly, discourage it from eating grain-based starters. We want the calf to eat starter, as this is what develops the rumen and encourages even faster growth.
To combat this, when feeding whole milk, we use a particular milk powder combination known as a balancer or extender to lift the overall calories and protein intake but try to hold the fat at a level the calf can handle.
Traditional CMRs are high in fat, so they don't help this fat-satiety effect.
ProviCo Rural launched ProviCo ENHANCE into the market in 2023, providing dairy farmers with this valuable tool. ProviCo ENHANCE is 25 per cent protein but only 10 per cent fat, so it uses all the goodness of the whole milk fat but dilutes it back to a level the calf can more easily manage in a twice-a-day feeding system.
ProviCo ENHANCE helps provide the calf with the higher nutrition plan it needs but at 25 per cent of the cost of a premium CMR. In turn, this helps improve average daily gain and, importantly, often lowers the cost of gain in most situations. Even better, improving milk nutrition encourages calves to eat more solid feed (Gelsinger, 2016).
In conclusion
Calf rearing can be a time-consuming job, incurring a lot of expense and heartache.
Next time you see a sick calf, don't just look for the bullet (the bug); stop and ask yourself about the gun and the finger on the trigger — it could well be inadequate DMI.
The good news is that the solution is available, improves the outcomes for all your calves, and reduces the cost of gain (but that’s another article).
For more information on ProviCo ENHANCE, colostrum supplements, milk fortification or calf rearing in general, contact your ProviCo calf specialist.
By Hugh Archibald, ProviCo Rural technical and nutrition manager.
