Journal of Chemical Ecology

, Volume 23, Issue 2, pp 275–288 | Cite as

Dynamics of Preference by Sheep Offered Foods Varying in Flavors, Nutrients, and A Toxin

  • Jian Wang
  • Frederick D. Provenza


We conducted two experiments to determine how toxicosis affected preference of sheep for foods varying in flavors, nutrients, and a toxin. The first experiment determined how toxicosis affected the preference of lambs (fed a basal ration of alfalfa pellets) for foods that varied in energy and a toxin. Thirty lambs (10/treatment) were given LiCl by gavage (0, 50, or 100 mg/kg body wt/day), and 1 hr later were offered for 15 min/day foods containing different amounts (low, medium, high) of energy (barley) and a toxin (LiCl) added to alfalfa. The proportions of barley and LiCl changed every three to six days during the 30-day study. The results showed: (1) lambs' food preferences were high > medium > low for barley in the absence of LiCl; (2) lambs quickly regulated intake of foods in response to changes in barley and LiCl concentrations, even with short exposures (15 min/day); (3) lambs maintained intake of LiCl at about 57 mg/kg body wt by adjusting intake of food containing LiCl in accord with the amount of LiCl they received by gavage; and (4) as barley levels increased, intake of foods containing LiCl increased. The second experiment determined the relative influence of flavors, nutrients, and toxins on food preferences of lambs. We did this by treatments in which different flavors (onion and oregano at 1%) were paired with different levels of energy (depending on the addition of wheat to rabbit pellets) or a toxin (LiCl). At six-day intervals, we varied the types of food offered, either changing the nutrient or toxin content and the flavors. The resulting analyses of preference showed lambs markedly preferred foods high in nutrients and low in toxins, regardless of flavor, when changes in food flavor were not correlated with changes in nutrient and toxin concentrations. Thus, in both experiments lambs quickly regulated intake of foods varying in nutrients and a toxin according to the lambs' toxicological and nutritional state. Even with brief eating bouts lambs discriminated accurately and exhibited little permanent preference or aversion in postconditioning preference tests. The lambs remained in an unbiased testing mode, sampling anew the food. This is adaptive because the toxin and nutrient contents of plants vary with season and location. Most taste aversion studies emphasize the permanence of aversions and miss the dynamic sampling power of animals.

Food preference flavor nutrients toxins learning sheep Ovis aries 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. BRATTSTENL. B. 1979. Biochemical defense mechanisms in herbivores against plant allelochemicals, pp. 200–270in G. A. Rosenthal and D. H. Janzen (eds.). Herbivores: Their Interactions with Plant Secondary Metabolites. Academic Press, New York.Google Scholar
  2. BRYANTJ. P.CHAPINF. S., III, and KLEIND. R. 1983. Carbon/nutrient balance of boreal plants in relation to vertebrate herbivory. Oikos 40:357–368.Google Scholar
  3. BRYANTJ. P.REICHARDTP. B., and CLAUSENT. P. 1992. Chemically mediated interactions between woody plants and browsing mammals. J. Range Manage. 45:18–24.Google Scholar
  4. CODYR. P., and SMITHJ. K. 1991. Applied Statistics and the SAS Programming Language. Prentice Hall, Englewood Cliffs, New Jersey, 403 pp.Google Scholar
  5. DUKEJ. A. 1992. Biting the biocide bullet, pp. 474–478in L. F. James, R. F. Keeler, E. M. Bailey, P. R. Cheeke and M. P. Hegarty (eds.). Poisonous Plants: Proceedings of the Third International Symposium. Iowa State University Press, Ames.Google Scholar
  6. DUTOITJ. T.PROVENZAF. D., and NASTISA. S. 1991. Conditioned taste aversions: How sick must a ruminant get before it learns about toxicity in foods? Appl. Anim. Behav. Sci. 30:35–46.Google Scholar
  7. FOLEYW. J.MC CLEANS., and CORKS. J. 1995. Consequences of biotransformation of plant secondary metabolites on acid-base metabolisms—a final common pathway? J. Chem. Ecol. 21:721–743.Google Scholar
  8. FREELANDW. J., and JANZEND. H. 1974. Strategies in herbivory by mammals: The role of plant secondary compounds. Am. Nat. 108:269–289.Google Scholar
  9. GARCIAJ. 1989. Food for Tolman: Cognition and cathexis in concert, pp. 45–85in T. Archer and L. Nilsson (eds.). Aversion, Avoidance and Anxiety. Lawrence Erlbaum Associates, Hillsdale, New Jersey.Google Scholar
  10. GARCIAJ., and RUSINIAKK. W. 1977. Visceral feedback and the taste signal. NATO Conference Series (III—Human Factors), Volume 2, Biofeedback and Behavior. Plenum Press, New York.Google Scholar
  11. HARBORNEJ. B. 1991. The chemical basis of plant defense, pp. 45–59in R. T. Palo and C. T. Robins (eds.). Plant Defenses Against Mammalian Herbivory, CRC Press, Boca Raton, Florida.Google Scholar
  12. HATCHERL., and STEPANSKIE. J. 1994. A Step-by-Step Approach to Using the SAS System for Univariate and Multivariate Statistics. SAS Institute, Cary,North Carolina, 552 pp.Google Scholar
  13. HICKSC. R. 1993. Fundamental Concepts in the Design of Experiments. Saunders College Publishing, New York, 509 pp.Google Scholar
  14. HILLD. L., and MISTRETTAC. M. 1990. Developmental neurobiology of salt taste sensation. TINS 13:188–195.Google Scholar
  15. ILLIUSA. W., and JESSOPN. S. 1995. Modelling metabolic costs of allelochemical ingestion by foraging herbivores. J. Chem. Ecol. 21:693–719.Google Scholar
  16. JOHNSONJ. H.CROOKSHANKH. R., and SMALLEYH. E. 1980. Lithium toxicity in cattle. Vet. Hum. Toxicol. 22:248–251.Google Scholar
  17. LAUNCHBAUGHK. L.PROVENZAF. D., and BURRITTE. A. 1993. How herbivores track variable environments: Response to variability of phytotoxins. J. Chem. Ecol. 19:1047–1056.Google Scholar
  18. LINDROTHR. L. 1988. Adaptation of mammalian herbivores to plant chemical defenses, pp. 415–445in K. C. Spencer (ed.). Chemical Mediation of Coevolution. Academic Press, New York.Google Scholar
  19. MANNERSG. D.PFISTERJ. A.RALPHSM. H.PANTERK. E., and OLSENJ. D. 1992. Larkspur chemistry: Toxic alkaloids in tall larkspurs. J. Range Manage. 45:63–66.Google Scholar
  20. MC ARTHURC.HAGERMANA. E., and ROBBINSC. T. 1991. Physiological strategies of mammalian herbivores against plant defenses, pp. 103–114in R. T. Palo and C. T. Robins (eds.). Plant Defenses Against Mammalian Herbivory. CRC Press, Boca Raton, Florida.Google Scholar
  21. MC KEYD. 1979. The distribution of secondary compounds within plants, pp. 56–133in G. A. Rosenthal and D. H. Janzen (eds.). Herbivores: Their Interactions with Secondary Plant Metabolites. Academic Press, New York.Google Scholar
  22. NRC. 1985. Nutrient Requirements of Sheep. National Academy Press, Washington, D.C., 99 pp.Google Scholar
  23. PROVENZAF. D. 1995. Postingestive feedback as an elementary determinant of food preference and intake in ruminants. J. Range Manage. 48:2–17.Google Scholar
  24. PROVENZAF. D. 1996a. A functional explanation for palatability, pp. 123–125in N. E. West (ed.) Proceedings, Fifth International Rangeland Congress. Society Range Management, Denver.Google Scholar
  25. PROVENZAF. D. 1996b. Acquired aversions as the basis for varied diets of ruminants foraging on rangelands. J. Anim. Sci. 74:2010–2020.Google Scholar
  26. PROVENZAF. D., and BALPHD. F. 1990. Applicability of five diet-selection models to various foraging challenges ruminants encounters, pp. 423–459in R. N. Hughes (ed.). Behavioural Mechanisms of Food Selection. NATO ASI Series G: Ecological Sciences, Vol. 20. Springer-Verlag, Berlin.Google Scholar
  27. PROVENZAF. D.PFISTERJ. A., and CHENEYC. D. 1992. Mechanisms of learning in diet selection with reference to phytotoxicosis in herbivores. J. Range Manage. 45:36–45.Google Scholar
  28. PROVENZAF. D.LYNCHJ. J., and NOLANJ. V. 1993a. The relative importance of mother and toxicosis in the selection of foods by lambs. J. Chem. Ecol. 19:313–323.Google Scholar
  29. PROVENZAF. D.LYNCHJ. J., and NOLANJ. V. 1993b. Temporal contiguity between food ingestion and toxicosis affects the acquisition of food aversions in sheep. Appl. Anim. Behav. Sci.38:269–281.Google Scholar
  30. PROVENZAF. D.LYNCHJ. J., and CHENEYC. D. 1995. Effects of a flavor and food restriction on the intake of novel foods by sheep. Appl. Anim. Behav. Sci. 43:83–93.Google Scholar
  31. PROVENZAF. D.SCOTTC. B.PHYT. S., and LYNCHJ. J. 1996. Preference of sheep for foods varying in flavors and nutrients. J. Anim. Sci. 74:2355–2361.Google Scholar
  32. VILLALBAJ. J., and PROVENZAF. D. 1996. Preference for flavored wheat straw by lambs conditioned with intraruminal administrations of sodium propionate. J. Anim. Sci. 74:2362–2368.Google Scholar
  33. VILLALBAJ. J., and PROVENZAF. D. 1997a. Preference for wheat straw by lambs conditioned with intraruminal infusions of starch. Br. J. Nutr. In press.Google Scholar
  34. VILLALBAJ. J., and PROVENZAF. D. 1997b. Preference for flavored foods by lambs conditioned with intraruminal administrations of nitrogen. Br. J. Nutr. In press.Google Scholar
  35. WANGJ., and PROVENZAF. D. 1996a. Food preference and acceptance of novel foods by lambs depends on the composition of the basal diet. J. Anim. Sci. 74:2349–2354.Google Scholar
  36. WANGJ., and PROVENZAF. D. 1996b. Food deprivation affects preference of sheep for foods varying in nutrients and a toxin. J. Chem. Ecol. 22:2011–2021.Google Scholar

Copyright information

© Plenum Publishing Corporation 1997

Authors and Affiliations

  • Jian Wang
    • 1
  • Frederick D. Provenza
    • 1
  1. 1.Department of Rangeland ResourcesUtah State UniversityLogan

Personalised recommendations