Latency of the jaw-opening reflex in the premature, preweaning and adolescent pig (hanford strain miniature pig, Sus scrofa)

The jaw-opening (digastric) reflex was elicited by electrical stimulation of oral mucosa in miniature pigs (Sus scrofa) varying in age from 5 days premature to 101 days post-term. The latency of reflex electromyographic activity varied between 12-14 ms in the most immature animals and 9-11 ms in the oldest animals. The very long-latency digastric responses found in the immature young of nesting mammals were not seen in the relatively precocious young of this species.