PREGNANCY scanning ewes for the number of lambs they are carrying can provide a benefit of at least $5.75 per ewe, according to the latest results in a University of Adelaide led project.
Agri-Partner Consulting principal consultant Hamish Dickson said some producers were reluctant to scan due to uncertainty about the economics of it or not having enough paddocks on their farm for smaller mobs, but the project 'Increasing lambing percentages through better use of pregnancy scanning technology' had found the business case stacked up.
Mr Dickson - who presented these figures at the Mackillop Farm Management Group workshop last week at Lucindale - said these benefits could be even higher in flocks lambing early in the season.
"The closer to the feed deficit, the higher this figure is because you are opening up more of an opportunity to reduce your feed requirements for the drys or offload them if you are selling them," he said.
This included preferential nutrition for twin-bearing ewes, which require far more feed than those not in-lamb or carrying singles.
The economic analysis, which looked at many different production scenarios, also found a $3.30/ewe average benefit for pregnancy scanning for 'wet or dry" (pregnant or not pregnant).
This was particularly useful in detecting joining failures early in the season and identifying animals that could be sold in a tight season.
Mr Dickson said it was important producers considered how they would use the scanning results on-farm rather than just collecting the data.
He also encouraged them to look at the broader benefits of identifying multiples, such as understanding lamb survival rates, when considering whether to scan.
"If we haven't pregnancy scanned we don't know if the foetal losses occurring pre-marking are high or low and where to focus our time and attention to get our lamb survival, our lamb marking and fertility rates increased," he said.
"We might find that someone is achieving 100 per cent lambing and the conception rate is only 120pc so the lamb survival rate is quite good but if someone is scanning at 170 or 180pc and still only marking 100pc, we know there is a big issue there that needs to be dealt with."
Those with self-replacing flocks can use this information to select replacements by knowing which lambs have been raised as twins.
Mr Dickson said producers were increasingly using foetal ageing of lambs at pregnancy scanning to understand whether the ewe had joined up at the start or end of the joining window.
"It may be simply looking at scanning for early and late (lambing ewes) and then potentially know that this group, whether it is a half or third, are due to start lambing now, whereas the other group have another two or three weeks," he said.
"We are going to run them in a separate part of the property and graze those bigger paddocks a bit longer."
Mr Dickson said it was also a great way to fine tune marking and weaning processes and have lambs in a tighter weight range.
"We are not weaning our youngest lambs that may only be six or eight weeks old, we can make sure they are all around 10 weeks old," he said.
PLANNING GIVES BEST RESULTS
TIMING of pregnancy scanning is everything for achieving 95pc-plus accuracy, according to Cousins Merino Services' Josh Cousins.
The Burra-based scanner, who works across the state, urged producers to plan with their technicians to be on-farm between 50-90 days after joining for the best results.
"At 35-40 days you are only seeing a tiny pocket of fluid on the screen, at 40-50 days you are up to 90pc accuracy and from 50 to 90 days you are right in the middle and seeing them well," he said.
"For multiples you don't want to be going any more than 80 to 100 days - after that it is a jumbled mess in that ewe and your accuracy decreases drastically."
Mr Cousins said it was important scanners had the correct dates of when rams were in and out and the ewes being scanned were off feed and water overnight for at least eight hours.
"If they have a full rumen or bladder, it just pushes their stomach out and can push the pregnancy around," he said.
"I might be scrolling around (in the uterus) and not see anything but then lean right forward and find it is pushed forward."
If you have a happy scanner they are probably going to do a better job.
- JOSH COUSINS, Cousins Merino Services
Fat ewes (anything above a condition score four) also created a similar issue as a full rumen, while joining periods beyond six to eight weeks made a high accuracy more difficult.
Among Mr Cousins other tips for success were watering down the race and forcing yard prior to scanning to ensure, as sheep moved the yards, dust was not circulating at the scanning crate.
"If you have a happy scanner they are probably going to do a better job," he said.
Mr Cousins said throughput numbers depended on individual set ups and whether lambs were being foetal aged but it was often possible to scan 400 ewes an hour.
It generally came down to having adequate staff so the sheep followed each other into the crate rather than how quickly the scanner is operating.
"You need at least two people (helping) but that third person makes a massive difference," he said.
"If a sheep is leaning back on my arm I am barely able to see what is going on inside of her and if I don't have any help letting her go, I might open the gate to get her to flow and she might bolt out."
Start the day with all the big news in agriculture. Sign up here to receive our daily Stock Journal newsletter.
