Utilization of Biomarkers to Study the Grazing Behavior of Herbivore Species

Abstract

Knowledge on diet selection of different herbivore species under each specific vegetation community is essential to develop and apply appropriate management decisions for each grazing system in order to, simultaneously, have a more efficient and sustainable utilization of pasture resources and the best animal performance level. In this chapter, traditional and more recent methodologies that can be used for studying diet selection of both domestic and wild herbivores are briefly presented, identifying the main advantages and limitations of their use. Particular emphasis is given to the utilization of epicuticular compounds, namely alkanes, long-chain fatty acids and long-chain alcohols, as faecal markers. The validation of their use is presented taking into account studies performed with different animal species under controlled conditions. The main advantages and shortcomings for their application to field studies with grazing animals are highlighted. Data indicate that the combination of these epicuticular compounds seems promising to overcome the enumerated constraints, allowing its application to more complex vegetation communities.

Evaluation of N-alkanes as Faecal Markers to Estimate Diet Composition, Feed Intake, and Digestibility in European Bison (Bison bonasus)

“…)ey can also be aggressive and unpredictable; thus the ability to reduce contact time and handling with animals improves safety for the person performing the handling and decreases the amount of labour needed to implement a successful nutritional study. Results obtained in metabolic cages studies indicate an incomplete recovery of n-alkanes in the faeces of ruminant species, pointing out to a possible positive association between their carbon-chain length and their faecal recovery [6,11,30]. Due to this association, it is expected that only the long-chain n-alkanes achieve high levels of faecal recovery and can provide accurate estimates of digestibility.…”

“…covering their nutritional needs for each specific situation (captive or wild) and providing efficient and sustainable management of the existing vegetation [3][4][5]. )is information is required to match areas of foraging with different types of herbivores and, as stated by Holechek et al [3], to select species compatible with the forage resource, to choose species to reseed, to predict the effect of overgrazing by different animals, to identify new species on which to base management, as well as helping to preserve species balance and achieving better animal performance [6].…”

“…Nowadays, the n-alkanes are the wax components most widely studied and used in herbivore nutrition studies as faecal indigestible markers [9] (Dove and Mayes, 2005). )e use of these markers allows to overcome accuracy and animal welfare issues and intensive labour that are major limitations identified in the traditional techniques, and present more extended results [6].…”

Assessment of diet composition of free-ranging addax antelopes (Addaxnasomaculatus) by the combination of microhistological procedures andn-alkanes and long-chain alcohols as fecal markers

“…Similar proportions were observed by Lin et al (2009) It should be pointed out that diet composition estimates were obtained using marker fecal concentrations corrected with data obtained in metabolic cage studies performed with cattle as they belong to the same family (Bovidae) and have similar body mass to antelopes. As some authors (Lin et al 2009;Ferreira et al 2017) suggest a diet composition effect on markers' fecal recovery, ideally, fecal recovery data on antelopes fed with diets similar to those normally selected by these animals in wild conditions should have been applied. The need of using precise D r a f t fecal-recovery corrections for obtaining accurate estimates of diet composition is highlighted by different authors for both n-alkanes (Dove and Mayes 2006;Lin et al 2007) and LCOH (Dove and Charmley 2008;Lin et al 2009) in ruminant species.…”

“…This allows the technique to be applied to complex situations where there is a high number of plant species to be discriminated (Dove and Mayes 2005). This increases the accuracy of diet composition estimate by providing a specific "fingerprint" for each plant species based on multiple marker profiles (Ali et al 2005;Ferreira et al 2017). Although the majority of previous studies were on domestic herbivore species, this technique could be used with wild herbivores species (Monks et al 2005).…”