Abstract
As a result of pioneering work of Hofmann (1973, 1989), nutritional ecologists classify ruminants into three feeding-type categories: browsers (“concentrate” feeders), grazers, and intermediate or mixed feeders. Hofmann proposed that these feeding types result from evolutionary adaptations in the anatomy of the digestive system and that one consequence is shorter retention of the digesta in the rumen of browsers, and thus a decreased efficiency of fiber digestion relative to that of grazers. We examined the hypotheses that (1) fiber digestion of browsers is lower than that of grazers, (2) salivary gland size is larger in all browsers than in grazers, (3) the browser's larger salivary glands produce larger volumes of thin serous saliva than those of grazers, and (4) thus, browsers have higher liquid passage rates than do grazers. We found that the extent of fiber digestion is not significantly different between browsers and grazers, although fiber digestion is positively related to herbivore size. In general, salivary gland size is approximately 4 times larger in browsers than grazers, but some browsers (e.g., greater kudu) have small, grazer-sized salivary glands. Resting (non-feeding or ruminating) saliva flow rates of mule deer (browser) and domestic sheep and cattle (grazers) were not significantly different from each other. Finally, ruminal liquid flow rates were not different between feeding types. We conclude that many of Hofmann's nutritional and physiological interpretations of anatomical differences amongst ruminants are not supportable.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Austin PJ, Suchar LA, Robbins CT, Hagerman AE (1989) Tannin-binding proteins in saliva of deer and their absence in saliva of sheep and cattle. J Chem Ecol 15:1335–1347
BakerDL, Hansen DR (1985) Comparative digestion of grass in mule deer and elk. J Wildl Manage 49:77–79
Baker DL, Hobbs NT (1987) Strategies of digestion: digestive efficiency and retention time of forage diets in montane ungulates. Can J Zool 65:1978–1984
Beauchemin KA, Buchanan-Smith JG (1990) Effects of fiber source and method of feeding on chewing activities, digestive function, and productivity of dairy cows. J Dairy Sci 73:749–762
Colucci PE, Macleod GK, Grovum WL, McMillan I (1984) Comparative digestion and digesta kinetics in sheep and cattle. Can J Anim Sci 64 Suppl:173–174
Domingue BMF, Dellow DW, Wilson PR, Barry TN (1990) Comparative nutrition of deer, goats and sheep. Proc N Z Soc Anim Prod 50:39–42
Domingue BMF, Dellow DW, Wilson PR, Barry TN (1991) Comparative digestion in deer, goats, and sheep. N Z J Agric Res 34:45–53
Foose TJ (1982) Trophic strategies of ruminant versus nonruminant ungulates. PhD Thesis, University of Chicago
Goetsch AL, Galyean M (1982) Effect of dietary concentrate level on rumen fluid dilution rate. Can J Anim Sci 62:649–652
Gordon IJ, Illius AW (1994) The functional significance of the browser-grazer dichotomy in African ruminants. Oecologia 98:167–175
Hanley TA, Robbins CT, Hagerman AE, McArthur C (1992) Predicting digestible protein and digestible dry matter in tannincontaining forages consumed by ruminants. Ecology 73: 537–541
Hendricksen R, Poppi D, Minson D (1981) The voluntary intake, digestibility and retention time by cattle and sheep of stem and leaf fractions of a tropical legume (Leblab purpureus). Aust J Agric Res 32:389–398
Hofmann RR (1973) The ruminant stomach (stomach structure and feeding habits of East Afrcian game ruminants). (East African Monographs in Biology, vol 2). East African Literature Bureau, Nairobi
Hofmann RR (1989) Evolutionary steps of ecophysiological adaptation and diversification of ruminants: a comparative view of their digestive system. Oecologia 78:443–457
Kattnig RM, Pordomingo AJ, Schneberger AG, Duff GC, Wallace JD (1992) Influence of saline water on intake, digesta kinetics, and serum profiles of steers. J Range Manage 45:514–518
Kay RNB (1987) Weights of salivary glands in some ruminant animals. J Zool 211:431–436
Kayouli C, Jouany JP, Demeyer DI, Taoueb H, Dardillat C (1993) Compartive studies on the degradation and mean retention time of solid and liquid phases in the forestomachs of dromedaries and sheep fed on low-quality roughages from Tunisia. Anim Feed Sci Tech 40:343–355
Kennedy PM, McSweeney CS, Welch JG (1992) Influency of dietary particle size on intake, digestion, and passage rate of digesta in goats and sheep fed wheaten (Triticum aestivum) hay. Small Ruminant Res 9:125–138
McArthur C, Robbins CT, Hagerman AE, Hanley TA (1993) Diet selection by a ruminant generalist browser in relation to plant chemistry. Can J Zool 71:2236–2243
McNaughton SJ, Georgiadis NJ (1986) Ecology of African grazing and browsing ungulates. Annu Rev Ecol Syst 17:39–65
Mould ED, Robbins CT (1982) Digestive capabilities in elk compared to white-tailed deer. J Wildl Manage 46:22–29
Murray MG (1993) Comparative nutrition of wildebeest, hartebeest and topi in the Serengeti. Afr J Ecol 31:172–177
Owen-Smith N (1991) Grazers and browsers: ecological and social contrasts among African ruminants. In: Spitz F, Janeau G, Gonzalez G, Aulagnier S (eds) Ongules/Ungulates 91. SFEPM-IRGM, Toulouse, pp 175–181
Poppi D, Minson D, Ternouth J (1981) Studies of cattle and sheep eating leaf and stem fractions of grasses. II. Factors controlling retention of food in the reticulo-rumen. Aust J Agric Res 32:109–121
Renecker LA, Hudson RJ (1990) Digestive kinetics of moose (Alces alces), wapiti (Cervus elaphus) and cattle. Anim Prod 50:51–61
Robbins CT (1993) Wildlife feeding and nutrition. Academic Press, New York
Robbins CT, Mole S, Hagerman AE, Hanley TA (1987) Role of tannins in defending plants against ruminants: Reduction in dry matter digestion? Ecology 68:1606–1615
Shaver RD, Nytes AJ, Satter LD, Jorgensen NA (1986) Influence of amount of feed intake and forage physical form on digestion and passage of prebloom alfalfa hay in dairy cows. J Dairy Sci 69:1545–1559
Silanikove N, Tagari H, Shkolnik A (1993) Comparison of rate of passage, fermentation rate and efficiency of digestion of high fiber diet in desert Bedouin goats compared to Swiss Saanen goats. Small Ruminant Res 12:45–60
Spalinger DE, Robbins CT, Hanley TA (1986) The asessment of handling time in ruminants: the effect of plant chemical and physical structure on the rate of breakdown of plant particles in the rumen of mule deer and elk. Can J Zool 64:312–321
Spalinger DE, Robbins CT, Hanley TA (1993) Adaptive rumen function in elk (Cervus elaphus nelsoni) and mule deer (Odocoileus hemionus hemionus). Can J Zool 71:601–610
Tatman WR, Judkins MB, Krysl LJ, Moss GE (1991) Gastrointestinal digesta passage and fermentation patterns associated with restricted intake of a low-quality forage in ewes. Small Ruminant Res 4:393–399
Uden P, Colucci P, Van Soest P (1980) Investigation of chromium, cerium and cobalt as markers in digesta. Rate of passage studies. J Sci Food Agric 31:625–632
Ullrey DE, Youatt WG, Johnson HE, Fay LD, Purser DB, Schoepke BL, Magee WT (1971) Limitations of winter aspen browse for the white-tailed deer. J Wildl Manage 35:732–743
Ullrey DE, Youatt WG, Johnson HE, Cowan AB, Covert RL, Magee WT (1972) Digestibility and estimated metabolizability of aspen browse for white-tailed deer. J Wildl Manage 36:885–891
Ullrey DE, Nellist JT, Duvendeck JP, Whetter PA, Fay LD (1987) Digestibility of vegetative rye for white-tailed deer. J Wildl Manage 51:51–53
Van Soest P (1982) Nutritional ecology of the ruminant. O and B, Corvallis, Oregon
Wickstorm ML, Robbins CT, Hanley TA, Spalinger DE, Parish SM (1984) Food intake and foraging energetics of elk and mule deer. J Wildl Manage 48:1285–1301
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Robbins, C.T., Spalinger, D.E. & van Hoven, W. Adaptation of ruminants to browse and grass diets: are anatomical-based browser-grazer interpretations valid?. Oecologia 103, 208–213 (1995). https://doi.org/10.1007/BF00329082
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00329082