Effects of restricted time allocation to pasture on feeding behaviour, intake and milk production of dairy sheep rotationally grazing Italian ryegrass (Lolium multiflorum Lam) in spring G. Molle A,C , M. Decandia A , V. Giovanetti A , C. Manca A , M. Acciaro A , G. Epifani A , L. Salis A , A. Cabiddu A , M. Sitzia A and A. Cannas B A Agris Sardegna, Dipartimento per la Ricerca nelle Produzioni Animali, 07040 Olmedo, Italy. B Dipartimento di Agraria, Università di Sassari, 07100 Sassari, Italy. C Corresponding author. Email: gmolle@agrisricerca.it Abstract. The effects of restricted time allocation (2, 4 or 6 h/day) to pasture and grazing day (Day 1, initial; Day 4, intermediate; Day 7, final) on feeding behaviour, intake and performance were assessed in Sarda dairy ewes, rotationally grazing Italian ryegrass plots for 7 days, with 21 days of regrowth. A randomised block design with two replicates per access time was used with six groups of six ewes each. The ewes were supplemented daily with 400 g/head of a commercial concentrate at milking, 300 g/head of lupin after grazing and 700 g/head of ryegrass hay overnight. Pasture variables, feeding behaviour, herbage and supplement DM intake, and milk yield and composition were measured on 12 days (4 per target grazing day). Plot average data were analysed by a bifactorial model with interaction, which was not significant. Sward height and herbage mass decreased between Day 1 and Day 4 (P < 0.05). Leaf area index dropped from Day 1 to Day 7 (P < 0.05). Eating time, as proportion of access time, and intake rate were higher in 2 h/day groups than in the others (P < 0.05). Nevertheless, herbage and total intake were higher in 6 h/day than in 2 h/day groups, being 4 h/day groups intermediate (P < 0.05). Herbage intake decreased with grazing period (P < 0.05). Fat normalised milk yield was higher in 6 h/day groups than in the others (P < 0.05) and in Day 1 and Day 4 than in Day 7 (P < 0.05). To conclude, time restriction below 6 h/day and pasture depletion, in terms of herbage quality, constrained intake and performance of rotationally grazing dairy ewes. Additional keywords: LAI, nutrition, sheep milk. Received 14 March 2014, accepted 12 May 2014, published online 10 July 2014 Introduction Restricting time allocation to pasture can tackle herbage shortage during periods of low herbage growth, provided that supplements are offered to fill the nutrient deficit, and can also increase the efficiency of herbage utilisation by reducing trampling effect and curbing pollution (Clark et al. 2010). Grazing cows submitted to restricted time access to pasture tend to compensate for the reduction in time allocated to pasture with an increase in intake rate and proportion of time devoted to grazing (e.g. Gregorini et al. 2009), whereas data on sheep are scanty. Orr et al.(2001) studied meal duration restriction from 120 min to 15 min in meat sheep grazing either perennial ryegrass or white clover under non-limiting sward height conditions. The authors found that the shorter the meal duration the higher the proportion of the time devoted to eating, so that intake rate did not change with meal duration in ryegrass or clover pastures. Iason et al. (1999) evaluated access time restriction from 24 h/day to ~8 h/day in lactating ewes continuously stocked on a permanent grassland at 6 cm or 3 cm of sward height, and found a significant decrease in herbage intake (HI) in the ewes grazing only the shorter sward. Information on the effects of time restriction and its interaction with pasture availability and quality in dairy sheep grazing Mediterranean forages is limited, as reviewed by Molle et al. (2004a). The objective of this study was to assess the effect of time allocation to pasture and pasture availability and quality on feeding behaviour, intake and performance of dairy ewes rotationally grazing Italian ryegrass (Lolium multiflorum Lam) in spring. Materials and methods Experimental design A randomised block design was used with two replicates per treatment. The treatments were: 2-h access to pasture (2 h/day), approximately from 0800 to 1000 Central European Time (CET); 4-h access to pasture (4 h/day), approximately from 0800 to 1200 CET; and 6-h access to pasture (6 h/day), approximately from 0800 to 1400 CET. The grazing day within grazing period (initial day, Day 1; intermediate day, CSIRO PUBLISHING Animal Production Science, 2014, 54, 1233–1237 http://dx.doi.org/10.1071/AN14376 Journal compilation Ó CSIRO 2014 www.publish.csiro.au/journals/an