British Journal of Nutrition

Animal Nutrition

Preference for wheat straw by lambs conditioned with intraruminal infusions of starch

Juan J. Villalbaa1 and Frederick D. Provenzaa1

a1 Department of Rangeland Resources, Utah State University, Logan, Utah, USA 84322-5230


We hypothesized that feed preference depends on the interplay between flavour and postingestive effects, and we tested two predictions based on this hypothesis: (1) lambs acquire preferences for poorly nutritious feeds paired with starch; and (2) preferences persist when starch is no longer administered. Twenty lambs were randomly allocated to two groups and conditioned as follows: on odd-numbered days, lambs in group 1 received onion-flavoured wheat straw and lambs in group 2 received oregano-flavoured wheat straw. On even-numbered days, the flavours were switched and starch (2-5-9.4% of the digestible energy received/d) was infused into the rumen of aU animals during straw consumption. Four periods of 8 d of conditioning were performed and on the 9th day of each period all animals were offered a choice between onion- and oregano-flavoured straw. After conditioning, starch administration was suspended and lambs were offered onion- and oregano- flavoured straw at weekly intervals for 8 weeks (extinction). Lambs strongly preferred the flavoured straw paired with starch, and this preference persisted during extinction. Thus, these results suggest that the postingestive effects of energy play an important role in the development of feed preferences of ruminants

(Received January 29 1996)

(Revised April 01 1996)

(Accepted April 16 1996)