Thursday, May 19, 2022

Satellites map sheep behaviour

Work by scientists in New Zealand and abroad is calling on some established technology to lift the lid on sheep behaviour.

A trial sheep fitted with an accelerometer, in this case for measuring chewing activity.

Work by scientists in New Zealand and abroad is calling on some established technology to lift the lid on sheep behaviour. Richard Rennie spoke to senior AgResearch scientist Patricia Johnson on the variety of work being undertaken.

Accelerometers and GPS monitors are not entirely new technologies in the New Zealand farming sector. 

Accelerometers have long been part of the tech helping dairy farmers determine cows’ behaviour changes when on heat, for example. 

But work by scientists across several research institutes, and the world, is discovering the value in the technology for better understanding the real time responses of sheep to shifts in conditions and health. 

AgResearch senior scientist Tricia Johnson is among those using the tech that brings some practical solutions to farming challenges. 

Accelerometers measure the rate of change in an object’s movement and are found in multiple applications, from navigation equipment to cell phones and fitness devices.  

GPS tech typically links the device to a satellite station to determine location.

But at a research level, Johnson and her colleagues are starting to get in-depth insights to how sheep behave in the field, reducing the reliance upon less than realistic lab-based trials that inevitably remove the environmental effects of real time activity.

“Attaching an accelerometer under the jaw for example enables us to monitor feed intake, right down to rumination patterns, recording the ‘chew-chew-burp-pause-chew’ type pattern. Detecting those subtleties can help better understand emissions, and in turn the feed efficiency of animals.”

The lab type comparison requires putting animals in a pen and feeding them lucerne-based pellets, quite different from a field environment.

Being able to constantly monitor animal movement is also useful in better understanding their response to illness or ill thrift.

“Looking at them, you get a split second to determine how they are doing. But this tech means their movement can be tracked. It could be a sick animal may have been standing in one place for several hours, feeling unwell.”

Scientists from NZ, Australia and the United States have recently studied the impact of ryegrass staggers on sheep. 

The on-animal sensors have detected changes in animal behaviour, exhibited through extraordinary movement, or lack of it. 

Machine learning analysis of accelerometer data showed the activity of sheep suffering staggers was increased in the morning and midday towards the end of the trial. 

Previous economic monitoring has suggested the value to the industry of being alerted to early signs of staggers and being able to manage it could be worth over $100 a hectare in additional income,and also eases the welfare impact of the condition.

Johnson’s team has also found analysing data that sheep exhibit quite varied differences in how far they will pursue feed.

“We have found there are some real sloths in there that will not venture very far during the day, while others will go far and wide.” 

The study ties in in with her work examining the genetic traits modern sheep require and the team have determined distance travelled is a repeatable trait that has a moderate level of genetic control.

The researchers have also used the GPS tech to better understand ewe behaviour around lambing time,and have highlighted unique patterns of behaviour in terms of where ewes lambed and post lambing movement.

“Two days after we deployed the GPS there was a massive storm and we found quite different behaviours exhibited. Some chose to just lamb out in the middle of it, while others did choose the tree line for shelter.” 

With more data and a larger sample, she believes scientists could get a better fix on how maternal behaviour, lamb survivability and lamb weights may all be linked.

Johnson says the compacting of GPS-accelerometer tech,and a lowering of its cost,would do much to take it beyond the realm of researchers and onto farms.

“In the past sheep farming has probably been the poor cousin to dairying which has a very clear cost:benefit equation in using this tech. Also, we would require greater numbers per farm.”

But she can also see the potential to have a sample of a flock armed with the tech, offering a sentinel like alert to the presence of risks like staggers, facial eczema, or parasite loadings.

“But of course, we are also learning that not every animal responds to these challenges the same and ideally one on every sheep would deliver a better flock health profile for the farmer.”

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