Rearing healthy calves

Article supplied by McInnes. McInnes 'Milk Bar' products are exclusive to RD1.

The main calf health problems encountered with calf rearing are nutritional scours, pneumonia, and cross sucking of ears, navels and udders after feeding. Many of these problems can be eliminated by correct feeding.

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 by enzymes in the abomasum before also passing into the intestine for absorption.

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.

Saliva balances the pH in the abomasum, which helps the milk to curd in the abomasum. It 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 calf's first and main defense against infection.

For optimal calf health always choose teats and feeders with a slow feeding gravity teat that has no valve in it (such as the Milk Bar Teat). This ensures your calves will produce the saliva they need for good digestion.

What to feed

• Birth - 4 weeks
  Feed milk at 10 - 12% of the calf's birth weight building to 15% over the first 2 weeks (4 to 6 litres per day for a 40kg calf) and grain or meal ad-lib. 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 abomasum.
• 4 weeks - 8 weeks
  Hay or pasture can be added to the diet when they are eating approximately 250 grams of grain or meal per day. Wean from milk when they are eating 0.75 to 1kg of grain per day.
• Weaning - 12 weeks
  The rumen will not be fully functional to properly digest pasture until the calf is about 12 weeks old, so grain should be fed to make sure the calf gets the required nutrients.

Healthy rumen, healthy calf

Developing a healthy rumen is important to ease the transition from a pre-ruminant to a ruminant animal. The pictures below 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

Did you know?

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. Milk in the rumen begins to ferment and has a harmful effect on the development of the rumen wall. Poor rumen development has a long term effect on the growth and production of the animal.

Always choose slow feeding gravity teats without valves and ensure the teat is no more than 600mm (2ft) off the ground.

Calf housing

• The ideal pen size is 1.5 to 2 square meters per calf.
• The ideal bedding for calf pens is sawdust, shavings or bark. The calf will then remain dry and clean. Do not remove sawdust, just keep adding a layer as necessary.
• Calves need good ventilation, in a draft free environment. You should be able to sit in a pen and light a match without the flame going out.
• Calves have no problem coping with the cold, but are unable to thrive in a wet drafty environment.