2 Mar 2022
Study by researchers at the RVC shows repeated needle use increases the required puncture force, raising chances of pain experience by the piglets.
Paul Imrie
Job Title
Researchers viewed needles under scanning electron microscopy to view the results of repeated use.
An RVC study has provided critical data to support recommendations that needles are changed between litters of 12 piglets to protect piglet welfare.
Research has shown that repeated needle use increases the required puncture force, which could lead to increased pain experienced by piglets.
More than 8.9 million pigs are reared for slaughter in the UK each year, with 60% reared indoors. The majority of indoor-born piglets require an iron injection in the first few days of birth to prevent anaemia, which reduces growth rates, and increases disease susceptibility and mortality.
Reuse of needles between animals is common in livestock farming, but failing to change needles regularly could cause pain and distress in piglets, researchers said.
In conducting the study, the research team – led by undergraduate veterinary student Kathryn Owen and supported by Nicola Blackie, senior lecturer in production animal science, and Troy Gibson, associate professor in animal welfare science – examined the force required to puncture the skin of a piglet cadaver for the 1st time, 12th time, 36th time and 100th time.
Researchers also 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 and the electron microscopy imaging showed visible damage to the needle tip after 12 uses.
Farmers were also surveyed about their needle usage as part of the research and, of 31 respondents, 81% of the farms reported needle reuse.
A total of 39% said they changed the needles between litters or earlier if damaged and 23% changed the needle when it felt blunt or damaged, after each injection session or when changing the iron solution bottle.
Speaking about the research, Ms Owen said it provided data to support the recommendation that needles should be changed between litters or even more often and hoped it would inform advice vets gave to their clients.
She 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.”
The full study is available online.
