The number of prime and Merino lambs dying within 24 hours of birth on Australian farms would fill 45 Olympic sized swimming pools or the MCG to 4.5m deep.
Riverina White Suffolk breeder and sheep industry consultant Murray Long described the loss as “horrendous’’ from a farm profitability and animal welfare point of view.
Mr Long, of Ardlethan, NSW, was a key speaker at the 2015 Australian White Suffolk Conference in Nuriootpa, SA, on February 16.
“Lamb survival is having a real drain on each farmer in the commercial industry – we need to be acutely aware of it,’’ he said.
Starvation and mismothering causes almost 60 per cent of losses followed by dystocia and exposure.
Nationally, marking rates across wool and meat breeds combined have averaged 90 per cent for 2010-2014.
Genetics and management could positively impact lamb mortality by more than 80 per cent, Mr Long said.
He said the Merino breeding objectives of increased fleeceweight and reduced micron decreased lamb survival.
“The average lambs-in-utero scanned in Merino ewes across Australia is 130 per cent with average marking rates of 60-90 per cent,’’ Mr Long said.
“Selecting for genetic fat is an insurance policy for lamb survival. Genetically fatter sheep produce heavier lambs at birth and birthweight drives survival.
“Chances are, not many 2.5kg lambs will make it through to weaning while 80 per cent of lambs weighing 5kg will make it to weaning.
“Genetic fat increases conception rates, ewe recovery after weaning, feed efficiency, lamb birth weights and lamb resilience.’’
Mr Long said management techniques for increasing lamb survival included condition scoring, optimum flock size and providing shelter.
Other techniques include scanning ewes 40 days after ram removal, identifying multiple bearing ewes and segregating them onto high energy feed.
As a rule of thumb, ewes carrying twins require up to 25 per cent more feed.
To reduce ewe mortality in late pregnancy, aim to lamb in condition score 3.5.
Mr Long said Merino producers using terminal rams should aim to keep 90 per cent of single lambs alive and 75-85 per cent of multiples.
“If you are only keeping 40 per cent of twins alive, farm profit is going nowhere,’’ he said.
As a member of the MLA Lamb Forecasting Advisory Committee, Mr Long said lamb survival was critical in the light of last month’s national flock survey revealing 40.6 milion ewes.
“Once the Australian sheep industry hits 40 million ewes, we are no longer a self replacing flock,’’ he said.
“Unless we drastically increase the number of lambs to weaning, our national flock is in danger of decline.’’
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