LEADING NEW Zealand vet Neil Chesterton visited the Murray region in April for a series of workshops and on-farm demonstrations focused on preventing lameness.
Lameness is a significant cost to dairy businesses and to herds, and in most cases it is preventable.
Improving cow flow, through good stockmanship and the maintenance of well-designed infrastructure, can help to reduce lameness.
With cows moving frequently between feeds, into and out of the dairy and yards, improving cow flow will also improve the efficiency of farm operations.
Understanding cow behaviour is the first step in designing a system that works well. Dr Chesterton gave the following examples.
Cows keep a watch on their surroundings, with their almost 330-degree vision, when their head is down.
Their vision is predominantly monocular, with only 25 to 50-degree binocular vision, which enables them to perceive depth, distance and speed. They need time to interpret what they see. They also have a blind spot directly behind them of about 30 degrees.
Cows keep their head down to watch their footing. Walking normally, a cow’s back foot will follow the front, landing in almost the same place she has lifted the front foot from and that she knows is clear of obstacles.
Even in the dark she must keep her head down so that if she stands on a sharp stone she can quickly lift or drop her head to take the pressure off the affected foot. When a cow is put under pressure, her head is forced up, increasing the risk of foot damage if she steps in the wrong place.
Flight zone and balance points
The flight zone is the space a cow needs to feel safe. The distance varies between cows and they have different zones for people and for more dominant cows. Looking a cow in the eye increases its flight zone.
Working on the edge of a cow’s flight zone, using balance points as the target of closeness or contact and moving quietly closer to encourage her to move, results in low-stress handling. The most important balance point of the cow is the shoulder.
Walking, tracks and obstacles
Cows are followers. They will follow set leaders and maintain set orders. These orders vary for collecting (walking and arriving at the dairy) and for milking.
Cows like wide laneways with plenty of space to move and a relatively flat platform to walk on. It’s a fine balance between having a laneway that cows find comfortable to walk on and one that allows for good drainage to prevent muddy conditions (also a risk for lameness).
Laneways should follow ridge alignments or catchment divides so that water naturally drains away. A gentle camber of no more than five per cent to parallel drains works well.
Cows don’t like steep slopes. A comfortable slope down or up has a gradient of 1 m for every 10m, but they can tolerate steeper gradients in short sections.
A critical area that needs constant maintenance is where the gravel laneway meets the concrete of the milking yard. One common cause of the track breaking down is yard wash-down water flowing onto the gravel.
A nib wall will reduce this risk. The nib wall of up to 20 cm must have well-defined edges. Although rounded nibs might look friendly to feet, cows often misplace the foot and slip down the face rather than taking a clear step over them. Cows will hesitate when they are put in this situation, slowing down the flow in and out of the dairy.
The yard and milking shed
Cows need space so they can move among each other in the dairy yard to re-order themselves. You should allow 1.8 to 2 square metres per cow for larger breeds (600 to 700 kg) and 1.3 square metres for smaller ones (450 kg).
When there is adequate space, cows at the front of the line, who prefer to milk later, will wait to be passed by other cows. When there is not, cows who like to be milked earlier will push through the herd, putting cows off balance and increasing the likelihood of misplaced footing.
Signs that cows are under too much pressure, or that there is not enough space, include side-to-side touching, elevated heads, bunching rather than following and low dominance cows reversing to escape from the head of dominant cows.
Concrete with a surface that is too smooth will affect cow flow. Grooves can be cut or the surface scabbled to reduce slipping.
If you use a backing gate, use it consistently and only to take up empty space or it will cause fear.
The backing gate should move no faster than 6 m a minute in a rectangular yard and no more than 12 m a minute in round yards. The backing gate should never be moved more than five seconds at any one movement and must never be used to push cows.
Cows are creatures of habit. Developing routines and a consistent culture around handling can help to reduce stress and will always improve cow flow.
It is important that everyone on the farm is attuned to cow behaviour and the systems in place for moving and milking cattle in a low-stress, low-pressure environment.