In the natural state, as a calf drinks from a cow, it drinks slowly with its neck stretched out, and the calf produces a lot of saliva. This helps to close the esophageal groove, which makes the milk bypass the rumen and enter the abomasum.
When the milk enters the abomasum rennin and other enzymes curd the milk. The whey is squeezed from the abomasum and into the intestine for digestion.
The milk curd is then broken down benzymes in the abomasum before also passing into the intestine for absorption.

The saliva which the calf has produced while suckling slowly then balances the pH in the abomasum, which helps the milk to curd in the abomasum. Saliva also contains essential enzymes such as lipase, which is necessary for digestion of fats, a vital energy source. It also contains natural antibiotic properties, which are a young calfs first and main defense against infection.
When a calf is fed fast, it cannot produce the saliva it needs to digest milk. This causes the calf to suck on ears, navels and udders, as well as its surroundings in order to try and make the saliva it should have produced while suckling. Fast feeding can lead to milk overflowing the esophageal groove and entering the rumen where it will sour and ferment in the absence of enzymes, leading to digestive upsets. Fast feeding and insufficient saliva can also result in lack of curding allowing whole milk to enter the small intestine, which leads to bacterial fermentation, leading to nutritional scours.

E-COLI NUMBERS MULTIPLY RAPIDLY WHEN IN CONTACT WITH RAW MILK,
WHICH IS A LEADING CAUSE OF NUTRITIONAL SCOURS IN YOUNG CALVES.

Check out the saliva drool produced by these calves feeding from a Milk Bar 6 fitted with Milk Bar Teats.

What to Feed and When..

There are 3 phases in the development of a calfs digestive system.
Liquid feeding phase: All nutrients are obtained from milk or milk replacer for about the first 3 weeks.
Transition Phase: Milk and starter rations both contribute to meeting the nutrient requirements. Start feeding starter ration as soon as possible. After 3 weeks the rumen will be developed enough for the ration to be contributing to the energy required for growth, but it will not be developed enough to digest pasture of hay. The calf can be weaned when it is consuming 800gm to 1kg of starter ration per day.
Ruminant Phase: The nutrients are derived from solid feeds through microbial fermentation in the rumen. By the time the calf is 12 weeks the rumen will be developed enough for the calf to thrive on pasture (or pasture based feeds) or grain.
Clean water should be available. Calves should drink water from a trough, not suckle it from a teat, as water must go to the rumen, not the abomasum.

Available MJME(approximate) per product. MJME equals MegaJoules of Metabolisable Energy. Whole milk- 3 MJME/Litre Colostrum- 3.4 MJME/Litre Whole milk powder- 21.9 MJME/kg Starter ration- 11-13 MJME/kg DM

A 40kg calf requires 6.8MJME /day for maintenance in ambient conditions, and more in cold, draughty, or damp conditions when the calf will use energy for warmth. Calves require 11.4 MJME to gain 1 kg of live weight.
For a 40kg calf to gain 0.8kg/day it will require a minimum of 15.9 MJME (6.8 for maintenence plus 80% of 11.4MJME to gain .8kg), which is 5.3 litres of whole milk.

Developing a Healthy Rumen ..

Development of a healthy rumen is important to ease the transition from a pre-ruminant to a ruminant animal.
These pictures show how the rumen of 4 week old calves have developed when fed various combinations of milk, grain and hay. A healthy rumen has a dark colouration which is caused by increased tissue mass and large blood vessels. The papillae in a healthy rumen are numerous and visible without magnification.

Milk only	Milk and Hay	Milk and Grain

In addition to feeding a combination of milk and grains to develop the rumen, you should also be aware of how your calves are drinking their milk. When a calf is fed too fast, too much milk, without the correct suckling action, or in the wrong feeding position, milk will enter the rumen where it will begin to ferment. Fermenting milk in the rumen will form abnormal acids and lower the pH of the rumen. This can cause long term damage that can effect the growth and production potential of the animal. Milk Bar Teats ensure all milk enters the abomasum, NOT the rumen.

If you would like further advice or to book a Free On Farm consultation please ring us on 0800 104 119.