Sucking, state, and activity: Term-preterm comparisons

Abstract

Forty Holstein heifer calves were assigned to be fed whole milk from either bucket, bucket with pacifier, nipple bottle, or nipple bottle with pacifier. The pacifier was a nursing bottle with an unperforated nipple. Calves were housed in individual hutches and fed twice daily. Calves were 3 d of age at first observation and were observed biweekly until 42 d of age. Observations were conducted beginning at either 1000 or 1400 h from September through March. A novel object (bicycle inner tube), selected to serve as a focal object for the sucking drive, was placed in the calf's environment and calf behaviors observed during the next 5 min.Time of observation did not influence nonnutritive oral behaviors (sniffing, licking, sucking, chewing, oral grooming, and nose licking). Time spent in nonnutritive oral behaviors increased with age. Regardless of availability of a pacifier, bucket-fed calves spent more time in sniffing the focal object than bottle-fed calves. Calves with access to pacifiers sucked other objects more than calves without pacifiers. The more curious animals spent more time involved in nonnutritive oral behaviors.