Genetic selection proves test under drought

August 10, 2018 | Kim Woods | Outcross Media

Genetic selection for condition score (muscle and fat) is paying dividends during the drought with Merino sheep able to handle the challenge for NSW grower Chad Taylor.

Unfed stud (spring lambing) ewes scanned 151 per cent in lamb in May during the second driest 12 months on record on his Wellington property, “Marapana’’.

Within the autumn lambing mob, 129 per cent of lambs were marked to ewes joined with 100 per cent survival from marking to weaning despite the drought.

Chad and his wife Louise have recorded just 75mm of rain this year, on the back of a failed spring at their Mumblebone Merino stud.

“Condition score maintains production when the pressure is on, with drought being a serious pressure for the stock,’’ Mr Taylor said.

“When combined with lambing in a dry period, it is extreme pressure so the animals with the genetic reserve of body condition score through muscle and fat, are the sheep that will continue performing.’’

The Taylors are due to begin lamb marking and are expecting above average rates.

“A significant part of that has been the genetics we have been selecting for and aiming for reproduction, which links closely to condition score,’’ Mr Taylor said.

“We hadn’t ever fed a grown sheep ever but this year we have been forced to supplementary feed.

“The feeding had not started when we scanned all (autumn lambing) ewes (including maidens) in February at 162 per cent in lamb.’’

The unmulesed mixed age ewes had cut an average of 3.6kg of 18.9 micron wool at the six monthly shearing.

The mixed age AIed ewes had an 88 per cent conception rate with a 157 per cent lambing potential while the maiden AIed ewes recorded an 84 per cent conception rate and 134 per cent lambing potential.

Mr Taylor said ewes in a low body score condition may lose up to 10 per cent wool cut if their lamb was lost shortly after birth.

The ewe’s loss in fleeceweight rises to 20 per cent if the lamb dies at weaning.

“Fat and muscle is an important profit driver, even for flocks focusing on wool cut, to maintain lamb survival,’’ he said.

To increase genetic gain in fat and muscle, Mumblebone has used one of the nation’s most elite Merino rams, Moojepin 120652, as an AI and natural joining sire for 350 stud ewes.

With semen sold to New Zealand, the ram was bought by Mumblebone from the Thompson family as a four-year-old proven sire in 2016.

The ram has Australian Sheep Breeding Values for growth, fat, muscle, yearling staple length, number of lambs weaned, early breech wrinkle, dressing percentage and intramuscular fat in the top one per cent.

Mr Taylor said the combination of carcase and wool traits was well suited to flocks wanting to inject serious fat and muscle.

More than 60 young rams sired by Moojepin 120652 will be offered by Mumblebone at the annual on-property sale on October 10.

“Those rams have been the clear leaders in their contemporary group for condition score (fat and muscle), and have been joined to top end wool ewes,’’ Mr Taylor said.

“The combination of wool in terms of quality, quantity and length, mixed with fat, muscle and growth on a polled sheep with good feet and structure, is the balance of traits we are aiming for.

“Once you have all of those traits, it makes it easier to combine them at a higher level and offer them as a balanced package in the sale.

“We are side sampling at the moment and time after time, these thumping bodies are coming through with beautiful wool – it is genetically exciting.

“Selecting for high performing animals under good conditions can be productive but those same animals under tough conditions are the ones which fall apart first.

“Sheep with condition score bred into them, continue to perform when the pressure is on.’’

With the wool market experiencing record high prices, Mr Taylor said there was a risk growers could select for wool traits at the expense of others.

“We can have fleeceweight and carcase to maintain a body condition to cut good weights of wool on heaps of lambs that survive, and continue to grow to have the best of both worlds,’’ he said.

“The efficiency of foetus conversion is an important part of breeding – we are not only saving those lambs but saving the wool cut on the mother producing those lambs, as well as the wool off the lambs themselves.

“High reproduction is such a valuable tool in terms of flexibility in restocking and driving turnover when times are good.’’

Mumblebone stud will stage a field day on Tuesday, September 11 in conjunction with the 12 Mile Stud Tour, an initiative presenting more than 700 rams for inspection by six studs, all located within 20 minutes of each other.

Participating studs are Allendale, Coddington Uardry, Boxleigh Park, Mumblebone, Glenwood and Gunnegalderie.