INTRODUCTION

There are a number of systems used for rearing calves in different parts of the world, which have been developed over the last 20 years. The objective of all these systems is to save time and labour in calf rearing, because in many countries labour is scarce and expensive. Even today, most dairy farms in Europe, UK, North America, Australia and New Zealand are family farms, worked by members of the farmer’s family and employing no extra labour. The feeding of the calves has to be done after all the cows have been milked and the dairy and milking parlours cleaned, so that any system which saves work is highly desirable. The systems discussed in this Lecture are based on the feeding of whole milk and milk substitute powders (see Lecture 8), and they require very high standards of management to be carried out successfully. They can be used in Southern Africa, but are not really recommended; however, as students you should know about them, and if you travel overseas, you will find many of these systems being used every day on commercial farms.

1. REARING CALVES ON GRASS

This system was developed in New Zealand, where most of the dairy farms are all grass farms, and all concentrate has to be bought from feed firms. Their grass consists of pastures with no veld grass as we know it, making it an excellent quality grass and highly nutritious when young. Many New Zealand herds calve in the spring, and the cows get very little supplementary feed; they milk off the grass alone. Due to this, their calves are born in the spring, and they are often only weaned onto grass.

By 8 weeks old, a calf can digest good quality young grass, because the rumen is working and the cellulose in the grass is being broken down by bacteria in the rumen. With calves, the limiting factor is the amount of grass that the calf can eat; being a small animal with a small rumen, the grass has to be of the best quality if the calf is to extract sufficient nutrients from it, to enable the calf to grow. The following factors are the important ones when considering grass for calves:

  • The grass must be young, fresh and growing. Old, fibrous grass that is at the flowering or seeding stage is no use because it is too bulky; the calves will eat it, but they will not be able to get sufficient nutrients to provide for their maintenance and growth.
  • Calves are very selective grazers, they pick out the grass they like and leave the rest. Because of this, they must have plenty of room in the paddock to wander around, selecting the best grass. In other words, the stocking rate must be low.
  • New established pastures are better than old permanent pasture for calves.
  • The grass must be clean; that is, free from worm eggs. Always graze calves ahead of adult stock. Put the calves into a paddock first, let them graze for a few days, and then move them to a fresh paddock. Calves pick up worms very quickly from dung left behind the cows.

The system generally operated in New Zealand is to rear the calves on the early weaning system, weaning them off milk at 5 weeks old. They are then taken from the calf house and put onto young spring grass, fed concentrates up to 8 weeks old and then left to feed on grass only. They must have clean water at all times.

A second system is that the calves are fed ad lib cold milk from a feeder, which is placed in the paddock and kept filled up with fresh cold milk. They get no concentrate at all, only cold milk and grass. The cold milk is introduced at 2 weeks old.

Figure 1: Cows with calves grazing in long grass

Source: smallfarms.cornell

1.   5½ DAY SYSTEM

This system is intended to save labour over the weekend period. The steps followed are:

  • It is suitable for batches of calves being reared on the early weaning system, and can be used with whole milk or milk substitute powder;
Ad Lib: as much as they want to eat; unrestricted.

Feed as for the normal early weaning system for the first 10 days. At 10 days old, the calves should be getting 3 litres of milk a day, fed in two feeds, together with clean water and concentrate ad lib;

  • From 10 days, continue to feed 3 litres a day of milk, but feed the milk from Monday to Saturday morning; do not feed any milk on Saturday afternoon and all day on Sunday. Commence feeding milk again on Monday morning;
  • Always make sure the calves have hay, water and concentrates available, and inspect the calves on Sunday, but do not feed any milk;
  • Wean the calves off milk at 35 days; and
Scour: to have diarrhoea
  • The problem with this system is that the calves tend to scour on Monday afternoon because they have had no milk over the weekend, and a feed on Monday morning.

3.   ONCE-A-DAY SYSTEM

This system was also developed in the UK to save labour. It can be used with whole milk or milk substitute powder, and like all these systems, it requires a high standard of management and very good hygiene. Buckets must be clean and sterilized before feeding the milk, and water and concentrates must be clean and fresh. Calves will not drink dirty water and eat sour concentrate.

  • Feed the calves on the normal early weaning system up to 2 weeks old. At this stage, they should be getting 3 litres of milk a day, fed at blood heat and in two feeds, together with clean water and concentrates ad lib.
  • On day 15, feed the calves their normal morning feed of 1.5 litres of milk. However, do not feed them in the afternoon. Over the next few days, increase the morning feed to 3 litres a day, but this must be done gradually. Continue to feed 3 litres a day, but in one feed in the mornings only.
  • Make sure the calves have clean water, hay and concentrates at all times.
  • Wean the calves off milk at 35 days.

4.   COLD MILK SYSTEM

Again, this system can be used with whole milk or a milk substitute powder.

  • Feed the calves normally for the first 7 days, but gradually reduce the temperature of the milk over the last 2 days.
  • After 7 days, introduce cold milk fed ad lib. This can be done using a milk churn with a special lid with teats – see the diagram below – or by means of an automatic feeder.
  • Feed at cold tap temperature; if milk substitute powder is being used, mix this with water from the cold tap.
  • Make sure the churn or feeder is kept topped up with cold milk, and give it a good cleaning once a day. The average consumption of the calves will be 6 – 7 litres of cold milk a day.
  • Clean water, hay and concentrates should be available all the time.
  • This method can be used to rear calves on grass, as in the New Zealand system already mentioned earlier in the Lecture.

Figure 2: A milk churn with an adapted lid

5.   AUTOMATIC MACHINES

These machines were designed in the USA and are now used in the main dairy farming countries. There are different types of machine, some for feeding cold milk only, and others which can be used for feeding milk substitute powder at blood heat.

This machine will feed calves in their single pens. Cold milk is put into the plastic bin, and the height of the bin above the ground maintains pressure in the tubes leading to the calf pens, keeping them filled with milk. The frame holding the teats moves backwards and forwards, so the teats are moved into the calf pens for 2 minutes in every hour; the calves get one feed every hour. This type of unit can be extended to feed up to 40 calves in a line of single pens.

Figure 3: A warm milk/milk powder feeder

This is a complicated machine which is made up of a container for milk substitute powder, a small tank for water, a mixer, an electric water heater and a time switch. The Machine can mix a set amount of powder with hot water, and the mixture runs into the glass bowl. The calf sucks the teat, taking one minute to empty the bowl. The machine then makes another mix which takes 3 minutes.

These machines are put into a pen with 15 – 20 calves for one machine, and they simply help themselves to a feed – it is labour saving, as the machine has to be refilled with powder and cleaned out once a day. Problems are:

  • The cost of the machine; these machines are very expensive;
  • The stronger calves can get more feed than the weaker calves in the group;
  • Infection can be spread from one calf to another from the teat. All the calves are drinking from the same teat and;
  • Milk cannot be reduced for one calf in the group, as in the case of sickness. Any calf with scour has to be removed from the group and put into a single pen.