Dm. Early et Fd. Provenza, FOOD FLAVOR AND NUTRITIONAL CHARACTERISTICS ALTER DYNAMICS OF FOOD PREFERENCE IN LAMBS, Journal of animal science, 76(3), 1998, pp. 728-734
We addressed two questions involving food preference. First, we determ
ined how a food's flavor and nutritional. characteristics affected pre
ference. In three trials, we offered lambs isonitrogenous foods differ
ing in energy (trial 1, 90% TDN; trial 2, 100% TDN; trial 3, 110% TDN)
; each food was offered in apple and maple flavors. We hypothesized th
at preference for apple-or maple-flavored food would decrease with inc
reasing duration of exposure (1, 2, or 4 d), and we speculated that ri
se change in preference would intensify when food contained inadequate
or excessive levels of energy. After eating food in one flavor, lambs
preferred the alternative flavor, even after only a 1-d exposure, and
preference for the alternative flavor was greater when the food had i
nadequate or excessive energy (P <.05). The second experiment determin
ed whether eating a food with rapidly or slowly digestible sources of
energy in the morning affected lambs' food preferences in the evening.
We speculated that lambs fed rapidly-digestible food in the morning m
ay prefer a slowly digestible food in the afternoon because slowly dig
estible food better maintains nutrient status throughout the night or
because preference for the rapidly digestible food decreases after exp
osure in the morning. We offered lambs isonitrogenous and isocaloric f
oods, that differed in rates of digestion, in apple and maple flavors.
Lambs fed rapidly digestible food in the morning preferred slowly dig
estible food in the alternative flavor in the evening. However, lambs
fed slowly digestible food in either flavor in the morning preferred s
lowly digestible food in both flavors in the evening (P <.05). These r
esults show that lambs' preferences change as a result of food ingesti
on, and the degree of change in preference depends on the nutritional
characteristics of the food. These findings further suggest food intak
e might be increased by providing a variety of foods to livestock on r
angelands, pastures, or in confinement.