Why you should check the feeding habits of cows

Nearly all cows sort their feed to some extent but the amount of sorting varies across herds.

In order to evaluate the level of feed sorting in your dairy farm, producers need to understand the symptoms, causes and consequences of the ‘vice’ before it becomes a problem, especially cows fed on Total Mixed Rations (TMR).

How to recognise feed sorting behaviour

Observing your cows, especially lactating ones eat, is always helpful in revealing the signs and behaviours that indicate over-sorting of feed.

When a well-balanced all-palatable ration is provided, cows bury their heads down onto the feed and eat aggressively from the top, with the head often staying on one spot or moving slightly.

Spilling of feed from their mouths is normally fairly low and eating may be done rapidly.

On the other hand, sorting raises a red flag on feed palatability and to practically see this, look for the warning signs expressed by the majority of cows.

In most cases, cows will show a pattern of circling the feed with their noses and nibbling. Lots of feed will be falling off their mouths and you will see holes burrowed in the feed in attempts to look for fresh, finer and palatable feed.

In the end, loads of less desirable feed is left in the trough and gets wasted.

Causes and consequences

When cows select what they want to eat rather than eating what the nutritionist planned for them, production and animal welfare will suffer.

Feed sorting indicates that cows get different diets as often showed in varying manure consistency, rumen acidosis and inconsistent feed intake from one animal to another.

There are common contributors to over-sorting by dairy cows. One such is the feed particle size. Who would eat bones first when served with plenty of beef steak?

Cows have a similar feeding intelligence. When forage fibre is cut long, cows will sort through the feed and consume the more palatable ones, a practice which is worsened when the lengthy chops are not favourite part of their diets.

Farmers may not chop forages to required sizes probably because the process is time consuming or they lack appropriate equipment.

Providing cows with lengthy stemmed forages promote selecting parts of the diet different than the intended. Cutting forages to desired lengths of about one inch really helps.

Next to particle size is effective fibre inclusion rate. Maintaining the optimal pH of the rumen requires that diets contain adequate amounts of physically effective fibre.

Since most farms aim at maximising milk production, diets provided mainly constitute concentrates and high quality forages that are limited with the effective fibre.

Sorting due to reduced intake of physically effective fibre may increase production of Volatile Fatty Acids (VFAs) and cause ruminal pH to drop below the optimal levels and lead to sub-acute acidosis.

Cows that suffer sub-acute rumen acidosis reduce production triggered by inconsistent feed intake, poor feed efficiency and reduced feed digestibility.

Such cows also get susceptible to diarrhoea and laminitis which results in discomfort.

Inclusion of enough effective fibre in the ration encourages rumination or simply chewing cud that results in saliva production.

Saliva contains buffers that help in maintaining the pH in the rumen and a more optimum environment for the rumen bacteria that digest the fibre.

Chews between 55-70 times per cud is normal for a healthy cow. Putting too much concentrates in diet is another risk. If using TMR, it is advisable to follow the level of inclusions of concentrate part as prescribed by your nutritionist.

Then again, farmers who supplement cows with dairy meal are not off the hook. It is obvious that dairy meal is desired by every cow and increases milk production but attempts to over feed them on this encourages heavy feed sorting.

This translates to huge waste of money, alters milk composition, lowering rumen pH exposing the cows to high risk of rumen acidosis.

Cows are social animals, but herd-level factors like overcrowding and limited access to feed troughs can contribute to feed sorting.

In a crowded unit, the dominant and older cows bully and sort out more fresh feed, leaving the timid ones with the less digestible portions.

You may sometimes wonder why some animals crowded for instance in a lactation herd are much thinner than their mates yet they are fed the ‘same’ ration. This is due to their inability to compete for feed trough space.

It is therefore a good practice to group cows differently. Feeding troughs should be easily accessible and placed at reasonable heights where at all cows can feed at the same time to minimise or eliminate competition when feeding.

Department of Animal Science, Egerton University.