Every farmer knows it is impossible to select a liner size that works for each cow and every individual teat.
Whichever liner you choose, a liner is inherently a compromise, irrespective of the milking equipment being used. You can only choose a liner to suit the majority of the herd. Yet every teat is an individual. Teats can be seen to vary widely in their dimensions and texture. They vary between cows and even between teats in a single udder. Furthermore, each teat’s dimensions change dramatically during the various stages of milking.
In a conventional milking cup, it is this compromised choice of liner sizing that means some teats will suffer from a poorly fitting liner. This in turn leads to several negative effects
Excessively high vacuum in the mouthpiece chamber of the liner causes swelling of the teat both externally and, crucially even though not visible, internally
The internal swelling – congestion – restricts the capacity of the teat canal slowing down milk flow and preventing full milk-out, leaving milk in the udder
Slower milk flow means the teats are under vacuum for longer than is desirable and makes them prone to increased trauma
With intelligent venting, the risk of congestion is significantly reduced because the ADF InVent milking cluster continuously controls vacuum levels on each teat individually
The unique InVent technology introduces clean, filtered air into the mouthpiece of the liner when vacuum rises to a threshold level
This acts to maintain the vacuum at the ideal “sweet spot” that is comfortable for the cow and also maintains peak milk flow
Calmer cows with fewer kick-offs
Faster milk let down and shorter milking times
More complete milk-outs and higher yields
Gentler milking action on teats
WHAT CAUSES EXCESSIVE VACUUM LEVELS?
At the start of milking, prior to full milk let down whilst milk flow rate is relatively low, the teat is exposed to high levels of vacuum in the mouthpiece chamber of the liner. Once the cow reaches peak milk flow, the teat plumps up, filling the barrel of the liner.
Vacuum levels reduce at this stage. Towards the end of milking, as milk flow decreases, vacuum levels once again rise exposing the teat to potential trauma and damage.
Oedema is the accumulation of excess tissue fluid in the teat and is normally preceded by congestion. Externally it can be seen by changes in skin colour and palpable ringing or thickening of the teat.
Over-milking can lead to hyperkeratosis which is the visible thickening and roughening of the skin around the teat orifice. It leads to increased risk of mastitis infection.
We asked dairy experts to conduct independent assessments of the ADF InVent system. Their comprehensive testing programme compares ADF InVent against an unvented milking system to look for differences in post-milking teat condition.