Farmers tackle issue of residue in milk
One of the country's top milk quality consultants has warned that dairy farmers risk contaminating their milk with teat spray residue if they do not ensure their cows' teats are properly cleaned before milking.
It was an issue the dairy industry had to stay ahead of, Quality Consultants New Zealand director Josh Wheeler said at the recent New Zealand Milk Quality Conference at the Claudelands Event Centre.
"We are an exporter of dairy products, we have markets to maintain and we have got customers whose sole diet is based on our infant formula. It's a high- risk market and we need to make sure our milk is residue free."
Dairy farmers typically spray their cows' teats in the milking shed as a mastitis treatment.
However, dairy companies have noticed an increase in the amount of milk picked up that has been graded because of teat spray contamination.
The efficiency of the New Zealand dairy industry, where one worker in the milk shed could milk an entire herd, fuelled the problem.
Unlike overseas practice, they did not prepare the teats before milking, he said.
"If we want to continue to work in that environment, we will have to take a different approach to teat sanitising."
Overseas, other dairy industries took the time to wash and wipe teats before putting the cups on for milking. Wheeler doubted they had a residue problem in their milk.
"Because of our efficient milking routine . . . and wanting to promote throughput per person, we limit the amount of udder preparation."
Trial work carried out showed there were no residue failures when it rained.
"The key message here is not removing the teat spray residue prior to the next milking."
He predicted a shift away from teat sprays that were a risk as farmers try to maintain their efficient milking systems.
"If farmers want to use high mix concentrations applied at high levels, they are going to have to look to prepare the teats."
There was also a risk of contamination on farms that used automatic teat sprayers when the teats were still attached to the cups.
If a farmer wanted to reduce the risk of residue, then the teat spray had to be mixed at the lowest concentration and they had to avoid over application.
"If you are going to use a mix with a high concentration, the advice should be that there is a high risk of failure."
He encouraged farmers to talk to their suppliers to get confidence around the product and find out what is in the product and what the risks are.
The industry had been very good at promoting teat spray usage but it needed to improve its messaging around teat spraying practises.
The labelling on products had to change to warn farmers if it could potentially cause a residue risk.
"We need to have a robust residue test in place to make sure these teat sprays that we do approve work and don't cause residues in milk."
Farmer feedback suggested they wanted something different to what companies were supplying.
They wanted thinner sprayers because they aerosoled better and provided better coverage of the teats.
The colour of the spray scared farmers. If it stained their equipment, there was an assumption there was a residue problem.
"So when the teats are coming back in for the next milking and are coloured, you start to worry about what product is on those teats," he said.
Those spray chemicals that failed the residue test were thick, gluggy and sticky.
"Some of the products out there are actually leaving visible residues that you can pull off," he said.
Some farmers had mistakenly thought it was the skin of the cow peeling off from the teat spray when it was the residue.
"It was actually the teat sprayer forming a layer on the teats."