How to lick pain

by Sarah Haines

ows know how to lick the pain associated with birth -- literally, say U of G researchers.

Carlos Pinheiro Machado, an animal and poultry science master's student, and Prof. Frank Hurnik believe the amniotic fluid cows ingest by licking newborn calves minimizes post-birthing pain.

The researchers say tests they performed at the Elora Research Station suggest there's a "placental opioid enhancement factor" in the fluid, meaning it has an analgesic effect similar to ASA.

"When it comes to pain management in cows, Mother Nature knows best," says Hurnik. "Licking appears to help them feel better."

The researchers conducted their year-long project with 36 dairy cows. The animals were divided into two groups -- those that had the opportunity to lick their calves (and ingest amniotic fluid) after giving birth and those that were distanced from their calves immediately following birth.

Both groups were exposed to heat lamp-like devices in their stalls. Researchers observed how long the animals remained comfortable with the heat the lamps gave off. They found the cows that licked their calves tolerated it longer, suggesting an elevated pain threshold.

"We believe that the analgesic effect of the amniotic fluid was responsible for this increase in pain threshold," says Hurnik. "We don't know the chemistry at work -- we need to work with a chemist to analyse the fluid's composition."

The researchers say licking has another benefit. During the first hours after birth, mothers' licking stimulates the calves' circulation and motivates them to stand up and seek nourishment. It also helps new mothers focus on protecting and nurturing their newborns because the distraction of post-natal pain is reduced.

"This is valuable information for farmers," says Hurnik. "Understanding cows' behavior will help us improve the management of calving and consequently their well-being. We should try to understand these natural processes."

This research is sponsored in part by the Ontario Ministry of Agriculture, Food and Rural Affairs.