A 10 year project to develop a process to modify the breech of sheep is nearing reality as "Steining" reaches the end of a pre-commercialisation phase.
Developer of the process, Steinfort AgVet managing director Dr John Steinfort, told the 2019 Balmoral Merino Sire Evaluation trial field day that the Steining process had been used on sheep in the trial in November 2017.
"I am very happy with the results. These sheep have grown into their breech modification very well,” he said.
“The equipment testing allows us test its robustness so we can process 1000 lambs a day at lamb marking.”
He said woolgrowers using the process could declare their whole flock "ceased" or "non-mulesed".
Karabeal woolgrower Coby Brewis said they had used the Steining process on 1200 lambs, autumn and spring 2018 drop.
The autumn drop lambs were Steined at weaning and the spring drop at marking.
"Steining at lamb marking is the best fit for our management. We are really happy with the results and the benefits the process brings," she said.
The process involved the application of liquid nitrogen to a specific area of targeted skin on the breech of the sheep and each side of the tail.
The applicator could be adjusted to the width of the skin targeted and the volume of liquid nitrogen could be increased for bigger skin wrinkles.
The process took 15 to 20 seconds to complete and was computer controlled.
Dr Steinfort said the controller was set to go through one cycle per sheep with the jaws gathering and “tenting” the skin.
The process targeted the whole skin thickness (tertiary freeze), clamping the skin at the base of the tented skin and releasing liquid nitrogen in an upwards motion, freezing the targeted clamped skin.
Dr Steinfort said the underlying muscle layers were protected from the freeze action.
“There is a stinging action at application, similar to what we feel having a wart removed with liquid nitrogen and then the skin is numb after the application.
“Pain relief prior to lamb marking processes will reduce the impact of all procedures,” he said.
A study on the impact of Steining on Merino lambs showed there was no difference in average body weight gain of the breech procedure modified (Steined) lambs and lambs that were marked only.
Lambs treated with a surgical mules had an initial setback compared with the Steined group. After 267 days of the trial the surgically mulesed lambs still had a lower average body weight gain, Dr Steinfort said.
“In the 2018 pre-commercialisation trials we have seen differing degrees of breech wool retention due to both the sheep type and depth of freeze, which is related to liquid nitrogen dosage.”
