SEXED sheep semen is being used by major Australian wool, prime lamb and maternal seedstock breeders to quickly lift the number of superior rams and ewes for sale and spread genetic gains.
The technology is being adopted to replicate a sire’s superior sheep meat traits in all-male progeny satisfy demand for high impact plain-bodied rams to lift non-mulesed wool production and to lift ewe numbers in new breeds.
Total Livestock Genetics Paul Douglas at Camperdown in Victoria said sexed semen was provided for Murnong Farming at Inverleigh last year to produce all-female progeny and fast-track development of the Probreed Highlander flock. TLG is now undertaking other projects for sheep meat and Merino breeders, he said.
Mr Douglas said sexed semen had been mainly used in the dairy industry, but the sheep industry was just beginning to embrace the technology.
“Last year we did 115 doses (of sexed semen) and this year we will probably do 800-1000 doses.”
The cost of each dose of fresh sexed semen is about $35 and one dose is artificially inseminated in each ewe. Artificial insemination results can vary, but in one flock last year an 85 percent pregnancy rate was achieved with fresh sexed semen, compared with 82pc with fresh unsexed semen.
In an Australian Wool Innovation-funded project at the Wurrook Merino Stud in Victoria with Livestock Breeding Services, the laparoscopic insemination of about 300 ewes with female X-chromosome-bearing sperm at normal commercial doses achieved a 78pc pregnancy rate, while fresh sexed semen resulted in pregnancy rates as high as 65pc depending on sperm dose used.
Mr Douglas said some sheep breeders are looking to have semen sexed to produce more ewes from superior rams for flock recovery or “optimisation” of a genotype, and to yield more rams for sale from selected sires and dams. Most interest is coming from stud breeders, but there has also been interest from commercial first cross ewe breeders wanting to produce only ewe lambs, he said.
Sexed semen will intensify Lambpro sheep selection
On Twitter yesterday, Lampro principal Tom Bull said he was pumped about his first batch of sexed Primeline semen arriving in two weeks. The maternal and terminal seedstock producer said his flock’s high fertility was giving an excess number of ewes and a shortage of rams, and he had decided to AI 450 ewes with male semen generated by TLG.
“At the end of the day when you are getting 150pc of lambs you do get a lot of females coming through the system, basically more than we need.
“We’ve been short of rams for a few years now, so we are getting top proven rams and mass producing them – out of 400 ewes potentially you can produce 400 ram lambs.”
Lampro sold about 1800 maternal Primeline rams last year, but Mr Bull believed another 500-600 could have been sold.
“It’s almost a bit of the Attack of the Clones, most of our clients want the same ram, so from our point of view it’s about finding those super sires and just mass producing them.”
He said most ram clients want a similar spread of breeding values in their Primeline rams.
“We are going to test 30 young Primeline rams and out of that we just want two or three super sires that tick the box for growth, fertility, muscle, marbling and everything else, and just mass produce them for our clients.”
He said sexed semen will intensify selection in flocks.
“I think this will consolidate genetics more and really most lamb producers just want a son of the highest performing ram they can get.
“This will just facilitate that process.”
Pooginook to use sexed semen to satisfy “impact” ram demand
Pooginook Merino Stud manager John Sutherland said the flock donated two rams to TLG for sexed semen research two years ago.
“This year we’ve got a special order for a large client to breed a specific style of sheep.”
He said semen has been sexed from a specially selected plain-breeched Poll Merino ram with a proven record of low wastage with white crimpy 19.5 micron wool, and good fat and muscle breeding values.
“He has a pedigree of very low breech wrinkle and breech cover sheep.”
Mr Sutherland said the ram was joined last year to some selected horned stud ewes that proved his impact on breech wrinkle without affecting the overall balance of measure production traits — wool and carcase — in the progeny.
Mr Sutherland has now selected other stud ewes to be inseminated with sexed male semen from the sire to produce “impact” rams for the commercial client to quickly plain breeches in his flock.
Mr Sutherland said the approach will ensure the flock of this flock and others retains the core virtues of Pooginook genetics – white crimpy wool on plain-bodied sheep with “good make and shape”, high fertility, easy doing ability and improved fat and muscle.
Mr Sutherland said the stud’s ewes weaned 124pc of lambs last year, so with a lot of ewes available and ewe lambs being joined this year this meant Pooginook could afford to put some ewes into the sexed semen project for impact ram production. He said 560 stud ewes were being inseminated with sexed semen from the impact sire.
Mr Douglas said he also saw potential for the export of frozen sexed semen, but more research was needed.
“We may find that with direct laproscopic AI using sexed semen with two million cells per straw that one million cells might achieve the same desired conception rate, and that would be cheaper again.”