Will Swiss cheese makers ban automatic milking systems?

Tuesday, October 2, 2012

Robotic milking is now a feature of many new dairy barns in the main European milk producing countries. But processors are getting nervous about the effects on milk quality. Switzerland is the first country to consider penalizing farmers who choose to go automatic

by NORMAN DUNN

There's no argument that robotic milking has changed dairying completely, especially on family farms throughout Europe. But have side-effects on milk quality been ignored too long?

Certainly the Swiss Society of Cheese Makers (FROMARTE) is already considering a ban on automatic milking systems (AMS) for its milk suppliers.

FROMARTE director Jacques Gygax says a study ordered by cheese makers in Switzerland has found that raw milk quality from automatic systems is clearly poorer than that from conventional milking parlours. While somatic cell count and total bacteria count are both higher, the main contention is the increase in free fatty acids (FFA) in milk from automatic systems.

This is not the first investigation finding more damage is done to the membranes surrounding fat globules in the milk. Indirectly, this leads to the increase in the free acids. Cheese is certainly one of the most important products from the Swiss dairy sector and these free acids, especially hexanoic or caproic fatty acid, can result in cheese turning rancid. But other dairy products don't escape the effects of FFA, which result in what the technicians call off-flavours.

Last year, as reported in Better Farming at the time, one of Europe's largest milk processors, Denmark-based Arla Foods, reported similar quality issues with milk from automatic systems. This was especially important in Denmark where go-ahead farmers lead the rest of Europe in adopting AMS for their dairy herds. Arla reckoned high pumping pressures needed with many systems (more than 100 metres from robot to bulk tank) might be responsible for the increased presence of FFA.

The Swiss investigation seems to have largely dismissed pump action as a direct major cause and, instead, suggests the increased frequency of milking as a possible reason.

Already the section of Swiss cheese makers that specializes in Gruyére has announced that it will accept no more milk from any farmer introducing a robot milking system. Ten Swiss farmers with robot milking already supplying milk for Gruyére are being allowed to continue deliveries. But the quality of their milk is under intense investigation at the moment and a further increase in FFA will probably mean that the milk will be refused by the cheese makers, according to FROMARTE. The society also feels that the makers of other cheeses in Switzerland will also take this route and might eventually ban robot milking systems altogether.

More worrying for most farmers is the lack of consensus about what causes this increase in FFA. A Dutch survey reported by Dr. Kees de Koning from the University of Wageningen Livestock Research Institute, for instance, does consider pump action as a cause (physical damage to fat globule membranes) but dismisses increased frequency of milking.

Milking three times per day in a conventional parlour, for instance, results in a small increase in FFA but nothing like the rise when herds change to AMS, where milking frequency average is actually slightly under three times per day. The Dutch survey has shifted the spotlight a little towards agitation through air intake into the milk stream or air leakage from the clusters.  Robotic systems have been found to have three to four times higher air intakes during milking than conventional milking clusters.  

What about the type of AMS used? A Danish study in 2006 looked at FFA increases in milk from five different types of AMS. It found significant differences in FFA levels between the models. Unfortunately, though, there were no clear pointers to what difference in technical specifications might cause the FFA increases.  

The Danish report, from Morten Rasmussen of the Danish Institute of Agricultural Sciences in Foulum, identifies stage of lactation as important through the effect of higher yields and different levels of milk constituents, including fat. What it also focuses on is the effect of cooling the milk before pumping.

A related survey of 55 AMS herds showed that those with milk cooling problems had a higher incidence of FFA. Correcting the cooling faults took FFA levels down to below those of the average levels for conventionally milked herds.

All of which suggests there's still a lot of research work to be done. European farmers are hoping that practical solutions will be found before other leading processors start thinking about refusing deliveries from automatic milking systems. BF

Norman Dunn writes about European agriculture from Germany.