Ewe need more greens if boys are on your mind
Australian scientists may have cracked the holy grail of animal farming, discovering how to markedly manipulate the sex ratio of lambs.
Researchers at Wagga working with local sheep farmers in the NSW Riverina, have found that adding two handfuls of oats or grain a day to the paddock diet of female sheep for four weeks before they are mated with a ram, can cause up to 70 per cent of the resulting lambs to be born girls.
In stark contrast, leaving the ewe flock in a paddock eating only grass led to a much higher number of boy lambs being born five months later, with the lusher and greener the grass or lucerne available at the time of conception proportionally boosting the ratio of ram lambs born.
Ed Clayton, senior animal nutritionist with the NSW Department of Primary Industries at Wagga, said the early results and field trials looked promising, with woolgrowers often preferring to have more female lambs to build and expand their breeding flocks and boost genetic advances.
But some farmers prefer more male lambs, as they grow faster and reach a weight at which they are ready for eating quicker, or they may operate a merino stud selling adult rams for breeding.
Dr Clayton said it appeared that the Omega-3 fatty acids in green grass fed to the ewes just before mating — also found in salmon, oily fish, nuts and green vegetables — was responsible for more male lambs being born.
Oats and most cereal grains — as well as eggs — are high in Omega-6 fatty acids, which seem to deliver more female offspring.
Dr Clayton acknowledged there were potential implications for humans in his groundbreaking research, which reinforces other findings that the diet of the pro- spective mother at the time of conception can influence the gender of the child.
He said it was still too early in his sheep feeding trials to emphatically suggest a woman wanting a baby boy should drink lots of green kale smoothies and eat salmon while trying to become pregnant, while a woman desperate for a girl should stick to muesli, rolled oats and porridge.
On his Holbrook sheep property, prime lamb producer Tim Trescowthick has watched Dr Clayton’s nearby trials with fascination, believing that if farmers had the ability to manipulate or shift the sex ratio of their lambs in different seasonal conditions, it would be a very useful and flexible management tool.
“In some years, I would be seeking more male lambs because they grow faster and are ready for market earlier, while after a drought I might be wanting more ewe lambs if I was restocking and rebuilding my flock numbers,’’ he said.
Lamb producer Tim Trescowthick with his flock of sheep on his Roachdale property near Holbrook, in southern NSW