UWA's Graeme Martin is the pioneer of teasing

It was the 1970s, pre-desktop computer days and Mr Martin was completing a PhD in animal science at The University of Western Australia (UWA).

He was monitoring how brain signals control a ewe's decision to ovulate, particularly with changes in night-length and responses to socio-sexual signals (today more commonly known as teasing or the ram effect).

In other words - how to induce ovulation, outside of seasonal breeding and at a time sheep do not usually ovulate.

"I remember plotting those hormone pulses, like blips, and thinking bloody hell," the now professor Martin said.

"Their response to the smell of a new or unfamiliar ram was so violent and fast.

"I expected the blips to slowly drift up but instead they responded in seconds - it was astonishing."

This year, professor Martin celebrates 50 years at UWA as a student, teacher and major contributor to agricultural research.

His roots can be traced back to growing up on a Wheatbelt sheep and cereal farm, working in Europe as a research scientist and teaching livestock and agricultural science at the university he was once a student at.

Professor Martin's research has primarily been based on animals using the 'three Ps' - photons, pheromones and phood (food) - to breed successfully.

And if you're a WA sheep producer, there's every chance you're using his research findings - like 'teasing' - in your everyday farming practices.

The discovery of the brain signals for teasing in the 1970s has been a highlight of professor Martin's extensive career in science and sheep reproduction.

A Merino ewe was known to best ovulate in February to May.

However, professor Martin found when a ewe was joined with an unfamiliar ram - outside of the usual breeding cycle - she produced the brain signal, which released an egg only two days later.

"Within a second of being introduced to the ram the ewe's brain switched on," professor Martin said.

"The blips increased even faster than I could take a blood sample.

"She smelled the ram and, if it was one she hadn't met before, she produced an egg."

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Realising the ewe remembered the smell of individual rams, professor Martin and his team decided to look inside the memory area of the brain.

What he found was that the new smell created new cells and a new memory - meaning the ewe would remember the ram the next time they met.

It is believed this memory lasts for six weeks.

Suddenly, management became easier for sheep farmers and the view ewes had to be kept away from all rams quashed.

They simply had to make sure 'novel' males were used as teasers.

Professor Martin then moved his attention and research to the nutrition of the ram, again monitoring the hormonal blips produced by the brain.

Since the 1980s, farmers have known if you feed rams lupins their testis will grow.

"I discovered when we gave lupins to the rams the brain blips increased within six hours," professor Martin said.

"Knowing lupins were good food, the brain decides to put more effort into reproduction by making the testis grow, producing more sperm and impregnating more females."

Professor Martin also studied 'flushing', a trick in which feeding sheep lupins for three days increases twinning rates.

However, this had to be done within a specific three-day window of the cycle, leading up to ovulation.

"The reality is you don't know exactly when a sheep is about to ovulate unless you put rams in for teasing," professor Martin said.

"So with this method, all the ewes smell the ram at the same time, their blips turn on and they produce eggs at the same time - their cycles are synchronised.

"Merino sheep in particular are tuned into their nutritional environment.

"With something like teasing and feeding lupins they can gamble on twins - whereas other genotypes normally wouldn't."

Professor Martin said teasing would only work when ewes weren't normally ovulating.

He said the best time would be anywhere from the beginning of December to the end of January.

"When I started as a student, we discussed chemical control of sheep production.

"There were 100 years of scientific effort leading to that point - trying to find the hormones, which control reproduction so we could manipulate it.

"Now, we have a complete reversal and are saying, 'let's avoid hormones'.

"In other words, teasing is better than hormone injections - it is clean."

This thinking led professor Martin and his colleagues to start thinking about 'clean, green and ethical' management.

"We saw how teasing could be combined with nutritional supplements, or flushing, to give us even more precise control over reproduction.

"When you tease your ewes, they all ovulate on the same day and you can use lupins to maximise the value by flushing to increase twinning rate.

"Then, knowing the ewes are going to progress through pregnancy and have their lambs at the same time, you can manage lambing conditions and have reduce lamb mortality.

"All of these things blend into a controlled process - even for flocks on big farms."

Beyond scientific discoveries, professor Martin said the friendships he had formed has been one of the most enjoyable parts of his career.

This includes the PhD students he supervised, colleagues, scientists, industry representatives and farmers.

Technically he retired from UWA in 2020, but this hasn't stopped him.

In more recent times, he has collaborated with Dr Johan Greeff, who was a geneticist with WA Department of Primary Industry and Regional Development, to focus on genetic resistance to gastro-intestinal worms in sheep.

While only in the early days, this could prove a gamechanger to the agricultural industry, particularly when it comes to preventing flystrike and avoiding mulesing.

"Dr Greeff had been breeding sheep resistant to worms for decades," professor Martin said.

"The problem was that some animals resistant to worms were still getting diarrhoea, apparently because they were over-reacting to the few worms in their gut.

"So, they'd still get get flystrike - we had not solved 100pc of the problem."

Professor Martin's team began collaborating with the Marshall Centre for Infectious Diseases to investigate the 'sheep-worm-flystrike complex'.

They investigated the immune system of sheep to try and figure out why some sheep would get diarrhoea, when others didn't.

Research showed that some genes affected by the selection were responsible for resistance to worms in the gut, causing rejection of the worms.

Other genes affected by selection were responsible for repairing the gut tissue that the worms had damaged.

Professor Martin said the damaged gut leaks salts, protein and water into the gut cavity, causing diarrhoea.

"We are still in the depths of that research," he said.

"Our aim is to use this new information to find a way to breed sheep that are more resistant to both flystrike and worms, so farmers don't need to rely on medication or mulesing.

"For me, science hasn't just been about making a discovery, it has also been about seeing how a discovery can change the world."