Observed differences in
stalled weanling horses versus paddock-reared weanlings using continuous
recording
C.R. Heleski, A.C. Shelle,
B.D. Nielsen and A.J. Zanella
Michigan State University,
East Lansing, USA
Significant differences in daily time budgets of stalled weanlings versus paddock-reared weanlings using instantaneous recording have previously been reported (Heleski et al., 1999). While the instantaneous sampling data provided reliable information about behavioral states, such as lying down, it did not sufficiently represent short-duration events.
Twelve Quarter Horse weanlings, average age 4.5 mo, were involved in this 56 d trial which began immediately post-weaning. Six weanlings were weaned in individual box stalls; six weanlings were weaned in a paddock which contained a run-in shed and very limited grazing forage. Based on pre-trial observation, 31 behaviors were defined to record. Six behaviors were later grouped into the category of social encounters: friendly behavior toward each other, mutual grooming, mutual fly swatting, aggressive behavior toward one another, play biting, and submissive champing. Six behaviors were grouped for analysis into the category of abnormal behavior: chewing the stall or shed wall, licking the stall or shed wall, kicking the stall or shed wall, pawing, and bouts of bucking and rearing. Three focal horses were observed at a time. Every five minutes an instantaneous record was written down. Between each instantaneous record, continuous recording was performed. Approximately 32 hours of data was collected for each of the twelve weanlings.
Paddock-reared weanlings performed an average of 3.3 ± 1.2 social interactions/hr. Stalled weanlings were unable to engage in social encounters. Stalled weanlings performed an average of 2.9 ± 1.8 bouts of an abnormal behavior/hr. Paddock-reared weanlings did have the option to engage in abnormal behaviors; however, their incidence was .28 ± .26 per hr.
An interesting and significant (P< .01) difference in frequency of performing investigative behavior was observed between the treatments. Stalled weanlings were observed to investigate 5.6 ± 1.5 times/hr; whereas, paddock-reared weanlings were only observed to investigate 2.25 ± .7 times/hr. It appeared that, over time, the stalled weanlings began to “sham-graze,” which was recorded as investigating. The stalled weanlings would pull hay out of the feeder onto the ground and then using their lips, sift through the shavings to retrieve pieces of the forage. Since paddock-reared weanlings were able to graze and engaged in grazing an average of 7.0 ± 1.3 times per hour, it is possible the stalled weanlings performed sham-grazing as a compensatory behavior.