A Mobile Transmitter

Press, Volume CIV, Issue 30745, 8 May 1965, Page 9

A Mobile Transmitter

Mr K. R. Drew, an animal research scientist from Invermay research station, is using an electronic technique to help him in work he is doing on sheep nutrition at Ruakura agricultural research centre near Hamilton.

By using small transmitters strapped to the backs of sheep he is able to record the noises the sheep’s jaws and teeth make when the animals are grazing and so study the grazing pattern without having to keep a 24-hour watch in the paddock. The grazing noises are transmitted back to a receiver in an office at the research centre and are recorded on tape for study by research workers at leisure.

Study of this nature is considered by no means impractical. When information obtained from the study is correlated with additional data obtained in other ways it could help to present a fairly accurate picture of sheep grazing habits, what pasture they select and the digestibility of that pasture.

What Ruakura scientists are trying to find out is how much feed a sheep eats, what it does with this feed, and how it modifies its grazing pattern according to the amount and quality of the feed available.

The research workers say these questions require accurate answers if better feeding systems for sheep are to be developed. Livestock nutrition is one of the most important fields of study at Ruakura and Mr Drew is gaining additional experience there before a nutrition section is established at Invermay. Last week at Ruakura a series of crunching noises were coming from a tape recorder. The sounds were those of a sheep grazing and when for a second or so there was no noise at all it meant that the sheep was pausing and deciding where to take the next bite. Mr Drew has learned to recognise the sounds by first watching the

sheep and recording at the same time.

While the recording was being played a ewe in a nearby paddock was grazing but she looked a little different from other sheep in the group. Strapped to her back was a small transmitter with an aerial protruding from it and two wires connecting the transmitter to small electrodes glued to the sheep’s jaws.

Housed in a small, flat box, the transmitters work off a 1.3 volt battery. Since they weigh less than a pound, including the harness to strap them on, they interfere in no way with the sheep’s freedom of movement.

The technique is being improved by Mr George Nicholls, an English radio engineer who came to New Zealand in 1960 to take up beekeeping but became one of the electronics staff at Ruakura instead. Mr Nicholls is holding the

ewe in the photograph above. The radio transmitter and aerial can be seen on the back of this sheep. This is an extension of a technique used successfully at Ruakura in the past to record changes in the rate of sheep’s heart beats following shearing in cold weather. The information has been used to determine whether it is safe to shear and how much wool should be left on under certain weather conditions.

Ruakura has used electronics in other ways—the development of a very sound type of electric fence and the measurement of pasture yield with a piece of equipment known as a radio grassmeter.

A number of scientists at the centre are doing their research with a spirit of adventurous enthusiasm best summed up in the words of one of them: “It might be a miracle if this works but let’s give it a go anyway.”