Repeated needle use increases the required puncture force, which could lead to increased pain piglets experience.
That is according to new research, which undergraduate veterinary student, Kathryn Owen, led the study with the support of Dr Nicola Blackie, Senior Lecturer in Production Animal Science, and Dr Troy Gibson, Associate Professor in Animal Welfare Science.
The Royal Veterinary College has said this research provides “critical” data supporting the recommendations of changing needles between litters, crucial for protecting piglet welfare.
Most indoor born piglets require an iron injection in the first few days following birth to prevent iron deficiency.
This is known as anaemia, which can reduce growth rates and increase disease susceptibility and mortality.
According to the college, without regular needle changes, the force needed to administer the injection increases and may cause pain and distress for the piglet.
The research team examined the force required to puncture the skin of a piglet cadaver for the first time, 12th time, 36th time and 100th time, mimicking reuse of needles.
Also, the RVC researchers then viewed the needles under scanning electron microscopy to assess the damage caused to needles over repeat usage.
They found that the puncture forces increased after 36 uses. The electron microscopy imaging showed visible damage to the needle tip after only 12 uses.
Survey on iron injection practices
As part of the research, the team also sent a survey to a sample of UK pig farmers, asking about their iron injection practices.
From the 31 respondents, 81% of farms reported needle reuse. Of these, only 39% changed the needle between litters or earlier if damaged.
23% changed the needle when it felt blunt or damaged, after each injection session or when changing the bottle of iron solution.
Kathryn Owen, the lead researcher on this paper and undergraduate veterinary student at RVC, said:
“Needle reuse increases the force required to puncture the skin; this indicates blunting which could cause pain and distress of piglets.”
“Electron microscopy shows that after 12 injections, the needle tip is visibly blunted,” she concluded.
According to the college, this “vital” research provides essential data to support the recommendation that farmers should change needles between litters of piglets or more often.
It said it will also help inform and change the advice vets give to clients and their own practices when reusing needles.
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