During the 2018 Graham Centre Livestock Forum held in Wagga Wagga, Dr Sue Hatcher addressed the issue of identifying those ewes which are restricting the flock performance.
Dr Hatcher is a director of Makin Outcomes, an independent research and development consultancy speacilising in applied sheep genetics, reproduction and fibre metrology based in Orange.
“The industry is riding the wave with record prices, but there have been significant changes to the demographics of the sheep flock,” she said.
“The sheep flock has declined quite dramatically, but we are still getting record lamb slaughter numbers.”
Those increased slaughter numbers are due to the proportionate lift in ewe numbers across the Australian flock.
“We have never had this many breeding ewes in our flock,” Dr Hatcher said.
“Never before have we had this focus on wool production, on lamb production and reproduction, and particularly for Merinos.”
Never before have we had this focus on wool production, on lamb production and reproduction, and particularly for Merinos
Lifting the reproductive capacity of a flock depends on doing a lot of little things correctly, and producers were advised to continue the practices consistently.
Genetic improvement in reproduction is effective and produces permanent gain in the flock, and using the results of trials Dr Hatcher showed the benefit which can be achieved by identifying those ewes with lower fertility.
“Compared with the ewe which weaned lambs twice at two and three years of age, the ewe which was dry twice was a lot less fertile as she got older, she weaned a lot fewer lambs and lamb survival was poorer,” she said.
“It was interesting to note the high performance among the older ewes was due to a high proportion of twins.”
Adopting the strategy of culling dry twice ewes and retaining the proven ewes for additional lambing opportunities requires changing from a fixed age structure.
Dr Hatcher questioned the practice of selling the ewes once they have reached their fifth year.
“Join them again, and maybe sell them at six and half or older if they are sound,” she said.
Cull passengers to lift flock returns
You have ewes in your flock which consistently don’t perform well and you have ewes which consistently perform above expectations.
Identifying the low performing ewes was the message Dr Sue Hatcher imparted during the 2018 Graham Center Livestock Forum held in Wagga Wagga to a very receptive audience.
By selecting ewes to retain in the flock based on their own reproductive performance, a boost to the net reproduction rate can be achieved in the current generation.
“Identifying those ewes who wean lambs as young sheep is a really good indicator of their productive capacity through her lifetime,” Dr Hatcher said.
“The theory is at two and three years you identify your non-performers and those who are dry twice are taken out of the breeding flock.”
They can be retained if they are good wool producers, but there isn’t any advantage in continuing their presence in a joined mob.
“We are left with our proven performers who are getting pregnant and weaning their lambs, so why not keep them for a bit longer?”