As well as common lamb castration methods there are a couple of new methods that can be used in England:
- Castration with a crush clip (e.g ClipFitter)
- Castration with use of anaesthetic simultaneously (e.g Numnuts®)
The following methods are not currently approved for use in England:
- Immunocastration
- Chemical/hormonal castration
There is less evidence about the impact of these practices on animal welfare, productivity, profitability and/or environmental sustainability, compared with the more common methods.
Castration clip (ClipFitter)
This technique combines aspects of both rubber ring castration and the clamp technique.
It uses a clip that is clamped around the scrotum. The clip must be applied using a specialised tool, similar to a set of pliers.
The clip crushes the nerve and spermatic cords almost instantly, and the blood supply is subsequently cut off.
The ClipFitter method is authorised by the Scottish government for use in lambs up to three months of age without anaesthetic, as it is seen to be equivalent to burdizzo clamping.
The law is different In England and Wales, where the ClipFitter method can be used in lambs up to 7 days of age, as it is seen by Defra and the Welsh Government to be equivalent to rubber ring castration.
You apply the clip in a similar position to a rubber ring/clamp, and it remains on the animal until it is shed with the wasted scrotum from around three weeks after application.
In this way, it is similar to combined castration with rubber ring and Burdizzo clamping, but in one step.
A range of applicators and clips are available to accommodate lambs of different sizes (5–20 kg). It is very important that the appropriate size of clip is used for each lamb.
Care must be taken to ensure that clips are applied across the scrotum rather than pointing ‘head to tail’ to prevent trapping the penis in the clip.
The ClipFitter method was trialled by Scotland’s Rural College (SRUC) in 2022 and the results of this study indicate that young lambs (less than seven days old) castrated with ClipFitter expressed similar behaviour to uncastrated handled lambs, and showed a significantly lower pain response compared to rubber ring castration.
In older lambs (4–5 weeks old), ClipFitter caused an increased pain response shortly after application compared with the clamp method plus pain relief.
However, after 18 minutes, there was no significant difference seen between lambs which were castrated with ClipFitter, the clamp method plus pain relief, and uncastrated handled lambs.