Calf Feeding and Management
Future Prospects

Introduction
The current economic growth in the Irish economy has resulted in the scarcity or unavailability of casual labour on many dairy farms. In the past, casual labour was available for calf rearing, thereby removing this task from those milking the cows. Secondly, farmers are looking for "quality time" to pursue social or recreational activities and the concept of evening milking followed by feeding of calves does not facilitate the concept of "quality time". Thirdly, the requirement to register calf births and obtain a passport before calves can be sold off the farm of birth results in many calves remaining for longer periods on the farm of birth than heretofore. The challenge therefore is to provide a calf rearing system with minimum labour or to time for calf feeding off peak time, i.e. mid-morning or early afternoon.

Milk Feeding Systems
Currently, the most common system is warm feeding of milk or milk replacer twice a day by bucket to calves which are individually penned for the first week and then group penned, with 4 or 6 calves per pen thereafter. The calves receive a daily allowance of concentrates from a trough usually located at the front of the pen. Water may be supplied from a self filling water bowl or may be manually carried to the pen from a cold water source. There are a number of options which can be employed which will significantly reduce or re-organise the calf rearing labour input.

1. Once a day feeding
This system is designed to feed the minimum amount of milk replacer daily and thus promote solid feed intake. Calves are weaned off liquid feed at an early age, usually about 6 weeks, after consuming 12.5 kg of milk replacer. The early weaning schedule shown in Table 1 is suitable. In this feeding schedule the milk feed is offered once daily from 7 days of age (Day 1) for a 35-day period.

Table 1. Early weaning feeding schedule. *Calves are weaned after 35 days provided that they are consuming 750 g of concentrate daily.
Period: 1-5 days

• Milk replacer (g/day): 250
• Liquid (litres/day): 2

Period: 6-35 days*

• Milk replacer (g/day): 375
• Liquid (litres/day): 3
  

This system depends on a high overall standard of husbandry and housing and suits the experienced calf-rearer. Calves on this system should be eating at least 750 g of solid feed daily, immediately before weaning.

A recent experiment at Grange compared an early weaning system which involved feeding 12.5 kg of milk replacer and abruptly weaning after 32 days with the Grange bucket feeding routine which involved feeding 25 kg of milk replacer and abruptly weaning at 42 days. While the calves offered 12.5 kg of milk replacer ate 10% more concentrate there was a 7 kg liveweight gain advantage at 84 days in favour of the calves offered the 25 kg of milk replacer (Table 2).

Table 2. Effect of early weaning calves off a reduced quality of milk replacer on calf performance 1 to 84 days
Weaned 32 d

• Milk replacer intake (kg): 12.5
• Concentrate intake (kg): 122
• Liveweight gain (kg): 43.3

Weaned 42 d

• Milk replacer intake (kg): 25
• Concentrate intake (kg): 111
• Liveweight gain (kg): 50.1

2. Teat fed from a well
In this system, the milk allowance is fed from a trough located between two group pens. The trough is designed such that there are a number of wells in the trough sufficient to allow each calf in the pen to have access to its own well and drink the milk allowance via a teat. One trough with 12 wells of 2 litres capacity would service two group pens each with 6 calves. The milk is pumped directly to the trough from a warm container in the dairy through a flexible hose which can be moved rapidly from trough to trough. Similarly, one trough with 12 wells with 3 or 4 litre capacity would service two group pens each with 6 calves on a once a day feeding programme. With this system of meal feeding, bedding and routine inspection of the calves is undertaken at off peak times. A joint Teagasc research project involving staff at Grange and Moorepark will evaluate this system against the more conventional bucket feeding system with respect to labour saving, calf health and performance. The main appeal of this system is that it facilitates feeding of restricted amounts of milk in a short-time frame.

3. Mobile teat barrow
Another group feeding by teat option is to use a mobile teat barrow with attached milk container tank, holding sufficient milk for all the calves in the pen, it is possible to teat feed and yet restrict the amount of milk offered. However, it is difficult to avoid some unevenness in intakes. Good stockmanship is required. There should be eight calves or less per pen, preferably of the same age and size. Slow, timid drinkers should be removed and all calves should be allowed suckle the teats for 3 minutes after their milk allowance is consumed. This will help to avoid navel sucking. The calves should be offered their milk allowance once daily from 7 days of age (Day 1). The feeding schedule is shown in Table 1. This system suits calf houses with pens designed to hold five to eight calves each and with passageways at least 2 metres wide.

4. Automatic feeding

Ad libitum Feeding of Whole Milk

Whole milk can be offered ad libitum warm via a teat from plastic containers. There are a number of specially designed automatic feeders available for whole milk feeding.

These feeders have the capacity to feed between 30 and 50 calves at any one time. Calves may be accommodated in four pens each containing 8 to 12 calves or two pens each containing 15 to 25 calves. The routine for automatic feeder use is similar to that adopted for feeders used to dispense milk replacer. When planning an ad libitum feeding system for whole milk the following should also be taken into account:

1. Calves can be trained to drink from a teat using a teated bucket once the calf is removed from the cow.
2. Milk should be taken cold from the bulk tank and transported to the feeding site.
3. Particular attention must be given to the method of transportation of milk from the dairy to the feeder. Forty calves can consume 120 gallons of whole milk daily. The mobile tank must be fitted with a pump which will ensure rapid collection and delivery of the whole milk.
4. All equipment used to store and transport the whole milk should be cleaned daily.
5. Never add fresh milk to stale milk.
   

Automatic and Semi-Automatic Feeders
Rearing calves using automatic systems is not easy and considerable experience is necessary to avoid losses. House design must be correct and many problems, such as extra urine wet bedding), are peculiar to this system compared to the bucket-rearing systems. The ad libitum feeding systems all need very diligent stockmanship and can never be used as a substitute for poor husbandry practices. The following operational measures should be observed when using an automatic feeder:

1. Calibrate automatic feeder at weekly intervals and for different brands of milk replacers and different batches of the same brand
   
2. Use only milk replacers which are free-flowing
   
3. Maintain regular checks on the mechanical operation of the automatic feeder as outlined in the manufacturer's manual
   
4. Clean feeder mixing-bowl daily and "milk lines" at least three times weekly
   
5. Set feeder nipple in calf pen 700 mm to 800 mm above floor level
   
6. Level of milk replacer in mixing bowl when full should be 50 mm below nipple height in order to avoid leaking
   
7. Provide a drain adjacent to feeder to remove all liquid out of the building
   
8. Always have the floor area sloping from the bedded area
   

Weaning Calves Off Ad Lib Systems
Weaning a calf off milk or milk replacer is always a critical operation. This task is more difficult in ad libitum than in bucket feeding systems. It is important to avoid any major change in growth at this stage. When calves have ad libitum access to warm milk replacer from an automatic feeder, they have little interest in consuming solid feed. Low intake of solid feed at weaning severely reduces performance immediately after weaning. Successful weaning depends on having an average intake of 750 g of concentrates per head daily in the week before weaning. Concentrate consumption in the period immediately before weaning can be increased by restricting the availability of milk replacer for 7 to 14 days pre-weaning. This can be done by:
a. Limiting the total quantity of milk replacer offered by restricting the daily allowance per calf in the period prior to weaning; 2 weeks before weaning allow 0.75 kg milk powder and 1 week before weaning allow 0.50 kg powder per calf per day, or
b. Limiting daily access to the nipples in the period before weaning; 2 weeks before weaning allow 12 hours access and 1 week before weaning allow 6 hours access per day, or
c. Reducing the bore of the pipeline by restricting the flow of the milk for 7 to 14 days before weaning, thus making it difficult for the calf to satisfy its appetite with milk and encouraging it to consume solid food.
d. Abruptly turning off the water heating system and reducing the concentration from 10 to 5% is also effective in reducing milk intake and thereby increasing concentrate intake.

It is important, however, to emphasise that it is difficult to avoid having to feed much less than 50 kg of milk replacer (100 gallons whole milk) per calf in ad libitum systems. Lower intakes than this can present problems at weaning. As already indicated, it is most important to ensure that each calf is eating 750 g of concentrates per day at weaning, otherwise liveweight setbacks will occur and the control of respiratory diseases in particular can be a problem.

Automatic feeding adds considerably to the costs of calf rearing as the amount of milk consumed will be approximately doubled that consumed in a conventional bucket system which offers the calf the equivalent of 40 to 45 gallons of milk. The main advantage of the system is that it can be serviced at off peak times and calf feeding and milking do not coincide. Calves sold off an ad libitum system will generally be in a more "fleshy" condition and therefore tend to command a high price in the market place.

Whole Milk or Milk Replacer
In the 60’s, 70’s and 80’s many companies spent much time and effort into developing calf milk replacers and alternative to whole milk. Firstly, the skim based calf milk replacers with the milk fat being replaced by animal or vegetable fat. Secondly, zero skim calf milk replacer as the subsidy paid on skim based milk replacers was decreased, the milk protein was replaced by vegetable protein. With these milk replacers no clotting occurs in the calf’s abomasum. However, with the advent of milk quotas and super levy payments, there has been a major substitution of calf milk replacers with whole milk feeding in either restricted amounts or in large quantities through ad libitum feeding. The proposed reduction in milk price under Agenda 2000 is expected to further increase the usage of whole milk on dairy farms.

Value of Whole Milk
At Grange we carried out experiments comparing whole milk and milk replacers at a similar daily dry matter intake and found that the calves offered the whole milk tended to have slightly higher daily liveweight gains. The increased gain associated with whole milk was primarily due to its higher energy value: it has a fat content (g/kg) of 35 compared with 23 for the milk replacer.

Farmers however, should be aware that the value of whole milk fed to the calf varies and decreases when milk is fed as a substitute for concentrates.

A guide to the value of milk at various feeding levels is as follows: (use instead of milk replacer or concentrate).
Up to 50 gallons - Milk Replacer
50 to 100 gallons - Milk Replacer and Concentrate
100+ gallons - Concentrates

In the future we can expect that dairy farms will be the principal location for the artificial rearing of calves. Whole milk will be the principal liquid feed. Management techniques to reduce the labour inputs into calf rearing will be applied. These will include calf feeding at off peak times and transporting the milk from the parlour to the calf house in a labour efficient manner. Farmers who purchase calves from dairy farms need to consider the age of the calf when planning a milk replacer feeding routine. If the calf is already 4 weeks of age at time of purchase then a shorter milk feeding routine is required.

A study conducted at Grange showed that feeding 12.5 kg compared to 25 kg to purchased spring born Continental X calves did not have any significant effect on growth rate. The calves on the 12.5 kg of milk replacer consumed more concentrates and were better prepared for weaning. Liveweight in mid-May was 104 and 100 kg for 12.5 and 25 kg of milk replacer treatments, respectively.

They received an individual allowance of 25kg of milk replacer powder offered warm at 38oC by bucket during the first 42 days and had ad libitum access to a concentrate ration throughout the 56 day period.

Milk Replacer Feeding Programme
Calves had ad libitum access to a concentrate ration throughout the 56 day period.

Period: 1-4 days

• Amount (litres/feed): 2
• Number of feeds daily: 2
  

Period: 5-28 days

• Amount (litres/feed): 3
• Number of feeds daily: 2
  

Period: 29-42 days

• Amount (litres/feed): 3
  
• Number of feeds daily: 1

Phil Rogers MRCVS, Lucan, Dublin, Ireland​
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