Factors influencing the inactive behaviours of stall-fed sheep under experimental conditions

Time spent on inactive behaviours (loafing, resting and sleeping) by 100 st all-fed sheep was recorded on three occasions for 24 consecutive hours. Bou t length and inter-bout length for each inactive behaviour were recorded. D ata related to behaviour duration, bout duration and inter-bout duration we re subjected to Kruskal-Wallis one-way analysis of variance by ranks to det ermine differences between the seven categories of sheep, viz. lamb (12), y oung (10), hogget (24), ram (12), pregnant ewe (12), lactating ewe (10), an d non-pregnant ewe (20). The Wilcoxon signed ranked test was used to study the significance of differences between day-time (part of the day with natu ral light, 06.01-18.00 h) and night-time (time of darkness, 18.01-06.00 h). Loafing (375 min per day) was the most frequent form of inactive behaviour followed by resting (252 min per day) and sleeping (56 min per day). Compa red to rains, lambs took more time (P < 0.05) for all three forms of inacti ve behaviour except loafing time during day-time. Diurnal variation (P < 0. 05) was observed for loafing time in hogget and resting time in non-pregnan t ewes. Bout length of loafing, resting and sleeping had durations of 9, 12 and 12 min, respectively, at day-time and 9, 13 and 15 min, respectively, at night-time. The inter-bout length during day-time and night-time was 23 and 29 min, respectively. for loafing; 52 and 53 min, respectively, for res ting and 154 and 220 min, respectively, for sleeping. For the three inactiv e behaviours, short duration bout length (< 16 min) was predominant; about 90% of total bouts of each inactive behaviour had duration of < 30 min. Res urgence of resting activity occurred either before 15 min or after 30 min o f completion of the preceding bout. Two-thirds of total inter-bout lengths for loafing and sleeping activity had durations of < 16 and > 30 min, respe ctively. Knowledge on the inactive behaviour will help to develop managemen t practices for rearing sheep under stall-fed conditions. (C) 2001 Publishe d by Elsevier Science B.V.