MASTITIS management is highly effective but far from conventional for Tasmanian dairy farm manager Richard Hori. That's no surprise given the herd is milked through a robotic dairy.
Mr Hori manages a 200-cow Holstein herd in the Pyengana Valley, which is a 20-minute drive inland of the north-east coast of Tasmania.
The herd split calves with 40 per cent calving in autumn and 60pc in spring and is milked through three Lely single-box units.
The farm was one of the first in Tasmania to invest in automatic milking systems (AMS) in June 2010. Mr Hori began working on the farm 12 months later and has since taken on the lease of the farm.
Milk quality is a priority for Mr Hori, who has a contract to supply Pyengana Dairy, a milk plant and cheese factory which adjoins the farm and is owned by the Tasmanian Food Co.
The herd's current average cell count for 2018-19 to date is 131,000 and ranges from as low as 30,000 to 218,000 depending on seasonal conditions.
While the AMS approach to mastitis management is different to a conventional dairy, it's not difficult, according to Mr Hori.
"Robotic milking is a totally different way of dairy farming with a reliance on sensors and computers - instead of people - to monitor issues such as mastitis," he said.
"In a lot of ways, the robots and the computer system become your eyes and ears on the herd.
"It doesn't mean you're not involved - you still need a good routine to constantly check things and act when the computer sends you an alert - but you're not relying on people in the dairy to identify and manage cows with mastitis."
Detecting cows
Every AMS unit on the Pyengana farm has on-line electrical conductivity sensors, which monitor each quarter in real time at every milking. The data collected is then used to generate an 'alert' when the conductivity level passes a set threshold.
Dr Nicolas Lyons, from NSW DPI's The Milking Edge* project, said that while electrical conductivity testing was the most common measure used to detect mastitis in AMS dairies, other sensor technologies were also used to detect mastitis. They include monitoring milk colour, temperature, yield, milk flow rates and the time between milkings. Some AMS units had on-line somatic cell counters as well.
"Research underway at the University is Sydney by PhD student, Momena Khatun, is looking at optimising which combinations of measurements could enhance mastitis detection in AMS dairies even further. Results so far look promising," Dr Lyons said.
Mr Hori makes a point of regularly checking his computer in the office to watch for alerts on cows going through the dairy. "The AMS makes identifying clinical cows straightforward, but once detected they need to be acted on," Mr Hori said.
"Mastitis management still means you have to have a routine.
"We don't have good mobile coverage in Pyengana so I can't access the data on a mobile phone, but I make a point of looking at the computer three to four times a day - depending the season - to see what is happening with the cows.
"The computer alerts are also backed up by manual observation of milk filters. We change two milk filters every day between washes.
"When you look at the reports generated by the system there are always a few new cows with cell counts going up and a handful of cows we need to keep an eye on. The detection and alert system allows us to act quickly on potential cases of mastitis - as soon as a quarter becomes infected and the cow is milked, the cow and infected quarter will appear on a report.
"The AMS system means we don't miss a case of mastitis and then have an undetected cow going through a number of milkings and affecting the herd's milk quality; which is the sort of thing which can happen in a conventional dairy."
Once the AMS identifies a cow as having a milk quality issue, the system is set to automatically draft the suspect cow into a treatment yard before the next milking. "Some systems will allow the computer to automatically draft suspect cows, but I tend to enter the cows into the computer manually," Mr Hori said. "I run a small herd, so I know all the cows and tend to know where they are in the grazing system and when a particular cow is likely to come through the dairy.
"I'll make myself aware of when a suspect cow is coming into the shed and will intercept her prior to milking and manually strip her out so she does not have to wait around in a holding yard for me to let her out.
"Before I treat her, I record against the cow's ID in the computer which quarters are treated, which drugs are used, the number of treatments and the withholding period.
"This is crucial because it's important the computer system knows to divert the milk from the treated cows away from the vat for the entire withholding period, plus an extra 24 hours."
The AMS will then automatically do a 1-2 minute wash after handling a treated cow with separated milk, before letting the next cow into the milking unit. This is instead of the normal 2-3 second rinse between standard milkings.
Mr Hori also uses the same system to record freshly calved cows, so the colostrum is redirected into a separate line at the dairy.
Quarter time
The ability of an AMS dairy to monitor and milk each quarter individually has significant benefits with mastitis management, according to Mr Hori.
"One of the advantages of the AMS is being able to get information on what is happening in each quarter of every cow, especially in late lactation," he said.
"There can be cows coming through in late lactation which are still producing at a high level but may have a milk quality issue in one quarter.
"The computer system allows me to set the AMS so that it will dry the problem quarter off in a cow, who is still producing well in the other three quarters.
"This means I can keep the cow in production rather than drying her off which can be important in managing numbers and total production. I want to keep cow numbers and not cull a cow unnecessarily."
Mr Hori grew up with his parents share dairy farming on the North Island of New Zealand but working in Tasmania has been his first experience with robotic milking.
"When I moved to Tasmania and first started working for the farm owners - the Healy family - in 2011, I couldn't believe how lucky I was to be working on an AMS farm," he said.
"I began leasing the farm in 2015 and am now in the process of buying their herd."
While the AMS frees up time which would otherwise be spent milking cows in a conventional dairy, more time is spent analysing individual cow reports and focusing on pasture management.
One of the keys to running an AMS dairy is ensuring cows keep coming to the shed and there is an even cow flow in a 24-hour period.
"It makes pasture management crucial and I tend to plan three to four weeks ahead where I want the cows to go," Mr Hori said. "If your pasture management isn't spot on and your plans are wrong, there are big ramifications on voluntary cow flow through the dairy and milk production suffers.
"Our average annual rainfall is in the order of 1100-1200 millimetres a year - which means it can get very wet and cold in winter.
"We can get a bit of mud on the laneway in winters but it's not a major contributor to mastitis because we only ever have small number of cows on the laneways at any one time."D
Contact: Nicolas Lyons, mobile 0401 650 073, email nicolas.lyons@dpi.nsw.gov.au.
*The Milking Edge is a collaborative industry project funded by Dairy Australia, NSW Department of Primary Industries and DeLaval, supporting AMS on Australian dairy farms. Dr Nicolas Lyons is the project leader.
