23 February 2010

3 minute read

Feeding and nutrition management can improve yields and fertility as well as reduce the length of time between calvings, said Mr Clay.

Housing plays an important part of this as cows must have constant access to food and water to improve performance and rumen health.

A number of cows are lost throughout the first lactation. This is because little is done to help them adapt into the larger herd, where they are having to constantly compete for basic essentials.

A rumen holds around 130-200 litres. A healthy rumen will have two contractions per minute. (The rumen is found on the left side of the animal.) To look for a healthy rumen, handlers must watch for regurgitation, re-chewing and re-swallowing.

When observing cows lying down, 70-75 per cent of them should be cudding. If not there is something wrong with the diet, warned Mr Clay.

Cud should be chewed 50-70 times, he says, when it is you know there is enough structural fibre in the diet.

Ideally rumen pH should be between 6.2 and 6.5 throughout a 24 hour period. However in reality this does not happen due to feeding patterns.

The higher the level of concentrate in feed, the more fluctuations there is in the pH and so there is an increased risk of sub-acute ruminal acidosis (SARA).

SARA is also known as chronic or sub-clinical acidosis. It is a digestive disorder that is characterised by extended periods of depressed ruminal pH below 5.5. Symptoms include loose muck, regurgitation of fluid, reduced cudding and cows can often be found crouched in the corner of a shed.

Common feeding practices often leave cows standing waiting for feed which reduces the pH and also reduces the feed conversion efficiency as nutrients are not broken down, which in turn reduces productivity.

Whilst cows with clinical acidosis can be cured, it is likely milk yields and possibly a fertility cycle will have been lost, says Mr Clay.

Nutritional values but also practical matters can be addressed to look at this.

The first thing to look at is the amount of straw in a diet and the length of it. Longer chops of straw will float to the top of the rumen and allow other feeds to be filtered down, it also allows the rumen to slow the breaking down process. However research from the US has suggested that shorter to medium length straw is more beneficial, but in the UK longer length straw is often used, says Mr Clay.

• Ensure all cows (particularly new heifers) have constant access to feed and water.
• Make sure they are not spending large amounts of time standing.
• Monitor cudding rates to know there is enough structural fibre in the diet.