The Animal-Plant Complex in Forage Palatability Phenomena

Abstract

No universally-recognized definition of the term “palatability” exists, but the concept of palatability is of more importance than any specific definition. Palatability is a complex phenomenon determined by animal, plant and environmental variables. Evidence exists that sheep and cattle sometimes possess different degrees of sensitivity to palatability factors when a choice of feeds is offered. Individual animals differ in their preferences for plant species. Some forage plant species and genotypes within species are consistently unpalatable to grazing ruminants. Specific characteristics, such as alkaloids, may be highly associated with lack of palatability of some plant species or genotypes. Natural and induced environmental factors frequently influence plant selection by ruminants. Experimental evidence reveals that forage species preferences of grazing sheep can be affected by preconditioning the animals to initially unpalatable species. Forage plant preferences by ruminants can be attributed at times to the senses of touch, sight, smell, taste, and instinct. Evidence discounts the existence of a generalized “nutritional wisdom” by animals as they select the forages that they consume.