BACKING GATES in the collecting yard can improve cow flow by 10-20%, but only when properly managed and milkers avoid chasing cows into the parlour, says Andy Johnson a Wisconsin-based vet.

“A major problem we find is milkers not allowing the backing gate to train cows to enter the parlour. Cows are easily confused when at one milking they are supposed to move with the gate, but at the next milking someone comes out to chase them in,” he says.

Dr Johnson believes gates operated by just one or two controls from the pit are inefficient. Each time the gate has to be moved, the milker has to walk to push a button. This wastes time and impinges on the milking routine.

He suggests using a backing gate controlled via a cable installed on both sides of the parlour, running the full length of the pit. “When the cable is pulled, only a bell or buzzer rings. This way, cows are trained to move on the bell rather than being pushed by the gate.”

In British parlours, the backing-gate control box is often sited at the cow entrance where the milker spends the least time, says ADAS parlour specialist Ian Ohnstad.

He recommends at least four control boxes or one rope down the centre of the parlour so the operator is never more than one step away.

“The other option is to fix the gate on a creep feature. This works on the principle that each cow takes up 1.5m sq of collecting yard. As cows are let in to the parlour, the backing gate moves this pre-measured amount.”

Again, this is ideally linked to an audible warning signal plus a hock rail which stimulates cows into action. But he warns against filling a collecting yard with cows and simply sticking the gate at the end.

“The cow at the front doesn’t know what’s happening and is rammed into the parlour, whereas the cows at the back are crushed and stressed, slowing milk let-down.” Instead, Mr Ohnstad advises moving cows in small groups – enough to fill four rows of the parlour.

Gates can cost £8000-£9000 or be home-made, but Mr Ohnstad believes most units can justify the cost. “The time saved can be spent on mastitis detection or better teat preparation.”