Calf feeding starts in the very first hour of its life. In addition to immunoglobulins, high-quality colostrum also provides your calf with sufficient energy, protein and minerals.

Since a calf is born with very little energy reserves, the rule for the quantity is: as much as possible! This may well be 10 % of the calf's body weight in its first meal, i.e. 3-4 litres. This is of vital importance to immunise the calf, but also for its nutrition.

And that brings us to the most important question: what should I feed? Whole milk or milk replacer (CMR)? Both types of feed have advantages and disadvantages, which will not go into here. But one thing is certain: if feeding programmes with high amounts of milk (i.e. > 10 l milk per day up to ad libitum) are planned, a very highly digestible milk must be used. This is usually whole milk or high-quality CMR (at least 40 % skimmed milk). This is especially the case for young calves.

It is advisable to continue feeding whole milk for at least the first 2-3 weeks, since colostrum or transit milk was given in the first few days.

We have already described the requirements for successful whole milk feeding in detail in our blog "The H&L Whole Milk Story".

Please remember a few important basic points when feeding CMR:

• Avoid concentrations of milk replacer that are too low or too high.

If you feed less than 120 g CMR/l, there is a risk of digestive problems because the protein does not coagulate well in the abomasum. At concentrations above 160 g/l, some milk replacers may not dissolve well and/or excessive osmolarity in the mixed milk may cause inflammation in the gastrointestinal mucosa. Optimum concentrations of feed are between 130 g/l and 150 g/l.

• Observe the mixing recommendation of the CMR manufacturers

There is much debate about whether the CMR concentrations in grams refer to a litre of prepared feed or a litre of water. There's a huge difference of up to 15% energy density. However, conventional mixing recommendations are unfortunately still thought of from the application perspective: i.e. the recommendation "grams per litre of water" only indicates how the milk is to be mixed and not how it is to be fed to a calf.

It is therefore better to use the term % dry matter (% DM). This clearly defines the nutrient density in the prepared milk. In this blog article, we use grams per litre of prepared feed to refer to the concentration.

Important: please note that the CMR concentration you set on the CalfExpert refers to the final mixed milk: a setting of 150 g CMR concentration means 15 % DM in the milk mixture.

In many cases, calves are still restrictively fed milk. This leaves the dairy cattle sector alone on a broad track in the agricultural world. The feed intake of offspring is not restricted in any other type of livestock. The belief that a limited supply of milk encourages calves to eat roughage at an early age, which still prevails in some cases, has been refuted by science and in practice many times over.

We now also know that metabolic programming can be expected to improve the lifetime performance of well-fed animals and hence achieve better long-term commercial results. It would therefore be wrong to save money in this area.

Which is why we say:

Always feed sufficient milk.

You should assume 12-15 % of body weight as the minimum quantity required. This means that a calf with a body weight of 50 kg should not be fed less than 6 l of milk per day. Satisfactory growth rates and better health can be achieved with more milk (approx. 15-20 % of body weight). You can start reducing the amount of feed in small steps after about 6 weeks. We recommend feeding calves with milk until they are 10-12 weeks old.

Essentially, you now need to choose between two basic approaches to feeding:

1. Restrictive feeding
2. Metabolic feeding with milk quantities that are higher than the theoretical nutrient supply would call for.

Restrictive feeding yields average growth performance at low cost, while metabolic feeding will maximise the performance potential of your calves. However, this will raise your feed costs.

A conventional feeding curve involves 3 different phases:

1. The initial feeding phase in the first 1-2 weeks of life
2. The subsequent plateau phase until the age of about 5-6 weeks
3. The final weaning phase until milk has been completely withdrawn.

How these phases are structured can vary greatly from farm to farm. The following section therefore only provides general recommendations that you can adapt to suit your individual farm and, where necessary, discuss with your feed consultant.

A calf weighing 40-50 kg has an energy requirement of 14-16 MJ of metabolisable energy based on a daily weight gain of 400 g. This can be provided by 5-6 l of whole milk or 800-1,000 g of CMR each day. However, young calves often feed hesitantly and slowly and therefore need to be carefully trained to ensure that they ingest sufficient energy.

With a restrictive feeding curve, for example, 6 litres of milk would be fed over a period of 7 days, and the amount of milk fed would then be slowly increased so that the calves receive 8 litres of milk after 14 days.

Calves are able to drink larger quantities of milk after 2-3 weeks.

In a restrictive feeding curve, you would feed e.g. 8 litres per animal per day and maintain this amount right through to weaning.

Around 22 MJ of metabolisable energy are required for daily gains of 800 to 1,000 g for a calf weighing 50 kg. This means at least 9 l of whole milk or 1,500 g of CMR. Consequently, quantities of over 10 l up to ad libitum intake are often set during metabolic feeding. This equates to a maximum of 15-18 litres when feeding by buckets with two feeds, as the buckets only have a volume of 9 litres. It is very easy to set high feeding quantities on the calf feeder, because the feeding quantity can be divided into small portions using the visit quantity function (see below).

You can set a daily amount of e.g. 12 litres if you do not explicitly wish to feed ad libitum at the feeder. A calf will then receive up to 1,800 g of CMR per day with an increased CMR concentration of e.g. 150 g/l feed.

The duration of the plateau phase should be based on the calves' intake of concentrated feed. Weaning can begin once the animals consume enough dry feed to compensate for the missing energy from the milk. You can find detailed information on this in our blog article "Powerfood for Calves".

As a rule of thumb, it can be said that gradual weaning can be started at a concentrate intake of 1 kg per day. It is difficult to determine this when keeping animals in groups. This is why weaning is usually undertaken according to age.

Since a calf's digestive system can only adapt slowly to solid feed, a reduction in the quantity of milk should be effected over a period of 4-6 weeks in order to avoid a drop in growth following weaning.

You could, for example, start at 6 weeks of age during the restrictive feeding curve and wean over a period of 4 weeks. When bucket feeding with the MilkTaxi, you could feed 2 litres each week. Appropriate markings on the hutches can help here.

Calf growth has proven to be a good alternative for determining the ideal time for weaning, since recording individual concentrate intake in group housing is difficult to accomplish in practice. This is because this additional growth is very likely to be accompanied by a higher intake of concentrate if all calves receive the same amount of milk according to the feeding curve, but some calves develop better than others. Higher daily weight gains are therefore a good indicator for earlier weaning.

Do not feed too little or too much milk in one meal.

Feed at least 2 litres of milk per meal. Calves will not be full and will not have their suckling needs satisfied if the quantities per visit are low. This can lead to unease and reciprocal suckling.

Also make sure that all quantities are about the same on visit:

• Good distribution: daily amount: 8 l, visit amount 2 l; i.e. 4 visits with 2 l on each visit.
• Poor distribution: daily quantity 8 l, visit quantity 2.5 l; i.e. three visits with 2.5 l and one visit with 0.5 l.

Limit milk feed to a maximum of 3 litres for young calves (up to the age of 4 weeks) and to a maximum of 4 litres for older calves. You should also focus on slow increases here, just as you do with feed composition or CMR concentration. You can easily set this transition on the CalfExpert calf feeder, e.g. in a visit quantity curve.

The metabolic feeding curve described in this article is not an ad libitum curve. Most calves would consume more than 12 litres. However, it is possible to program higher quantities on the calf feeder. However, missing call-off quantities must then be regularly expected and these will be added to the feeder's alarm list. The Holm & Laue CalfExpert accounts for this fact and only issues an alert when a calf's milk consumption falls below a critical threshold.

You can find out more about feeding recommendations for ad libitum feeders in the next blog article.