GPS helps keeping track of pasture

A cow on a Hamilton farm has a GPS unit attached as part of 
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A cow on a Hamilton farm has a GPS unit attached as part of a study by postgraduate student Jamie Haultain. Photo by Dairy NZ
Attaching GPS units to cows in a herd could one day play a role in helping the farmer predict which paddock needs to be regrassed next.

DairyNZ postgraduate student Jamie Haultain used the concept as part of his masters project and presented the information at a recent DairyNZ farmers' forum in Invercargill.

Mr Haultain put the global positioning system (GPS) units on collars of three cows in each of the herds he was studying on a farm near Hamilton, for a year.

The units, which cost $1000 each, recorded the paddock grazed each day by the cows.

The data was then downloaded daily.

He said he then compared the milk production and cow numbers that grazed the paddock to pasture grown (calculated from pasture walks). By using information from the GPS units he could tell which paddocks were entered each day and from there get a record of milk production generated from that particular paddock.

''By applying production back to the paddock grazed, we can get a record of which paddock was the most productive,'' Mr Haultain said.

''The analysis looks at pasture performance during the different seasons.''

He confirmed the accuracy of the information by pasture walks and plate metering and took into account seasonal variations.

''We have got a really good response in terms of [the relationship between] paddocks grazed and how much milk production.''

Using the information, farmers could rank their best and worst performing paddocks, and use that information for their pasture renewal and fertilising programmes as well as cultivar selection, he said.

''Not many farmers have that information.

''Most farmers have a big whiteboard in the dairy or a note pad that can get lost.

''This way farmers have an automatic performance measure.''

He said farmers tended to renew 5% or 10% of their paddock area each year.

''By not regularly measuring the paddocks they generally only have a limited idea of which paddocks do not produce well. The reality is that it is difficult to identify the best and worst paddocks without some form of measure.

''The key thing is they can work out if they are making the right decisions about which paddock to regrass.

''A good paddock can grow up to 100% more pasture than a poor paddock so what we are trying to do is show the farmers which paddocks are best.

''If they are not renovating the poorest paddock, they are not closing the gap [between the bottom and the top] and not getting maximum response to their grassing scheme.''

However, his data did not take into account supplement feeding.

Mr Haultain's next step is to complete his masters and he hopes to continue with the study later.

GPS units for dairy farms could eventually provide information on heat and lameness detection; grazing preferences; virtual fencing; misplaced, missing or stray cows and calving problems he said.

- by Yvonne O'Hara

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