Competition, activity budget and feed intake of ewes when reducing the feeding space

Abstract

Even if ruminants are fed roughage ad libitum, reducing the number of feeding places may have negative effects on both feed intake and behaviour. The aim of this experiment was to investigate effects of reduced feeding space on competition, activity budget and feed intake of ewes fed ad libitum on two types of roughages. A 3 × 2 factorial experiment was conducted with number of animals per feeding place (1:1, 2:1 or 3:1) and type of roughage (grass silage or hay) as main factors. A total of 48 pregnant, adult ewes of the Dala breed were randomly divided into eight groups of six animals; four of these groups were fed grass silage whereas the other four groups were fed hay. The ewes were video recorded for 24 h at the end of each experimental period, and the activities such as feeding, queuing and resting of each ewe were scored using 10-min instantaneous scan sampling. Displacements from the feed barrier were scored continuously for the first 10 min of every hour. Daily intake of silage was not affected by reducing the feeding space from 1:1 to 1:3, but for ewes fed on hay, the daily intake was significantly reduced by 6.8% ( P < 0.05). However, time spent eating hay was significantly longer than time spent eating silage ( P < 0.05). Irrespectively of type of roughage, time spent eating was significantly reduced ( P < 0.0001) whereas CV for eating was increased ( P < 0.05) when feeding space was reduced. Overall, the competition level was higher when the ewes were fed on hay than on silage (queuing: P < 0.01; displacements: P < 0.01). In the hay treatment, the time spent queuing increased from 0.3% in the 1:1 treatment to 5.3% in the 3:1 treatment, but this was not significant in the silage treatment ( P < 0.001). Number of displacements was low at one ewe per feeding place, but increased significantly when feeding space was reduced in the hay treatment ( P < 0.01). In conclusion, the ewes competed more for access to feed in the hay than in the silage treatment, and increased competition with reduced feeding space was only found when the ewes were fed on hay. Similar results were found concerning feed intake. Thus, the effects of reduced feeding space are likely to depend on the type of roughage used.