Whether collecting colostrum, keeping high cell count milk out of the tank, or milking mastitis cows, any reject milk system has to milk cows as efficiently as the conventional plant.
This applies whether dump buckets are used or a dedicated reject milk line is installed, says parlour specialist Ian Ohnstad of The Dairy Group.
“Otherwise there is the potential for uneven milking and teat-end damage, which create a starting point for future problems.
“The reject milk set-up should also be cleaned, maintained and – in the case of buckets – stored just as well as the main milking equipment.
There is no point leaving it dirty and expecting it to fire up perfectly after six months of non-use,” he says.
Units installing new parlours often baulk at spending another £5000-6000 on a proprietary dump line, yet this milks cows as well as the main plant.
As a totally separate system, there is no risk of bulk tank contamination and it is washed in place.
This means it is easy to clean, so is more likely to be kept clean.
What Mr Ohnstad tends to see is the old parlour stripped down and a new line for reject milk cobbled together from an old receiver and pipelines.
“This is usually okay for one animal, but once you have two or three it becomes overloaded and floods the system because it can’t get milk away quickly.
Milking is slow or incomplete and units drop off as vacuum disappears.”
A dedicated line also takes away the chore of moving milk around in buckets and is more efficient in block-calving herds, where many cows calve every day.
But he says there is an argument for using dump buckets to control the spread of Johne’s, where pooling of colostrum is not advised.
Milking into a dump bucket ensures a calf can be fed its own dam’s colostrum.
But aside from the numbers needed – four or five buckets to suit block calvings or TB reactors – which make it labour intensive, Mr Ohnstad says cows are usually not milked properly.
“Dump buckets have to have their own vacuum supply and a vacuum-operated pulsator often operates at a different rate and ratio from the rest of the plant.
Often the bucket is fitted with an inadequate sized clawpiece off the old plant, has a leaky lid and operates more slowly.
Yet cows using this equipment most are fresh calvers and mastitic, both critical groups for correct milking.”
He recommends buckets have liners changed at least every six months, using new rubberware, not second-hand.
They should be part of regular parlour maintenance and regularly checked to operate at the correct speed.
“Clean buckets after every use, rinse then scrub with a disinfectant.
This can be done at the end of milking for colostrum, but needs doing after every cow – with the cluster – for mastitic milk.”