Initial conditions and temporal delays influence preference for foods high in tannins and for foraging locations with and without foods high in tannins by sheep

Preference for foods is influenced by experience, which in variable environments changes as animals eat foods that differ temporally and spatially in nutrients and toxins. We hypothesized that variability can affect preferences by influencing the contiguity of food ingestion as young animals learn to forage. To test this hypothesis, we fed lambs two biochemically different foods, one with tannins (T—55.5% beet pulp, 30% grape pomace, 4.5% soybean meal, 10% quebracho tannin; 2.4 Mcal, 8% CP) and one without tannins (NT—35% barley grain, 62% alfalfa hay, 3% soybean meal; 3.0 Mcal, 15% CP) in two temporal arrangements: (1) dissociated in two separate feeding bouts (Group 1; Delayed arrangement) or (2) associated in a sequence in the same feeding bout (Group 2; Sequential arrangement). We then determined if these different associations influenced choice of foods and foraging locations. In Trials 1 and 2, NT and T were both at location 1, whereas either NT or T, respectively, was at location 2. In Trials 3 and 4, the choices were similar, but the NT offered was reduced to half the average intake in Trials 1 and 2. Throughout the trials, both groups of lambs preferred NT to T and they spent more time at locations where NT was present. However, lambs conditioned under the sequential arrangement always ate more T than lambs conditioned under the delayed arrangement, even when NT was available ad libitum at both locations. When the amount of NT offered decreased, lambs conditioned under the sequential arrangement foraged longer at locations with both NT and T or with just T. Even when both groups spent similar time at locations with NT and T, lambs conditioned in the sequential arrangement ate more T than lambs conditioned in the delayed arrangement. Thus, conditioning during initial exposure influenced preferences for foods and foraging locations. Our results help explain why the same food may be perceived differently by different animals, and suggest it may be possible to train animals either to use more diverse arrays of foods or, conversely, to be more selective.