Feeds And Feeding PDF

9 = KEY TERMS --------- OBJECTIVES ---------- - The balance of browsing versus grazing is different in goats compared with other domestic ruminants. - The browsing process in goats is only partly "driven" by bipedal grazing. - That as a consequence, goats will select different pla...

9 = KEY TERMS --------- OBJECTIVES ---------- - The balance of browsing versus grazing is different in goats compared with other domestic ruminants. - The browsing process in goats is only partly "driven" by bipedal grazing. - That as a consequence, goats will select different plant species than sheep or cattle, when confronted with the same biomass. - That within goats, diet selection will be affected by age, sex, buccal architecture/dentition, and physiological state. - Analyzing the validity of statements about dietary preferences and diet selection in goats. - That the evidence suggesting that goats digest forage better than sheep, or that they eat more of a given forage than sheep, is not conclusive. - The importance of dietary condensed tannins as one component of the diet selection process. - How to synthesize this knowledge into a comparative understanding of the processes of diet selection and intake in goats, compared with other domestic herbivores. 179 INTRODUCTION ------------ EATING BEHAVIOR AND DIET SELECTION ---------------------------------- 1. Species composition of the biomass/ season of year 2. Clover content of and clover position in the "sward" 3. "Presentation" of the biomass---zero grazing versus grazing; species in rows cf. mixed sward; species offered separately or together 4. Sward height, biomass; stocking rate 5. Condensed tannin content of species on offer 6. Dry matter content of the forage 7. Odor/flavor of the forage 8. Previous experience and adaptation of grazing animals; species of animal that grazed biomass previously 9. Differences in possible instantaneous intake rate between biomass components 10. Breed, gender, age, and physiological state of goats 11. Buccal architecture and integrity of teeth 12. Goats grazing separately or co-grazing with other species 13. Grazing height, bipedal versus quadripedal foraging **4** **3.5** **3** **2.5** **2** **1.5** **1** **0.5** **0** ***Quercus ilex Viburnum*** ***tinus*** ### Factors Influencing Diet Selection **100** **80** **60** **40** **20** **0**  - goats---1.65 m and 2.10 m - cattle---1.47 m and 1.90 m - sheep---0.87 m and 1.17 m **70** 1. Quantitative studies of the fate of condensed tannins during gut transit have shown substantial losses between intake and feces (e.g., Perez-Maldonado and Norton, 1996), suggesting the possibility of microbial metabo- lism of tannins in the gut. 2. One might expect that a herbivore's intake of a feed- stuff containing a secondary compound would be limited by its ability to detoxify the compound. The predicted consequence of this is that herbivores would choose a mixed diet to minimize the effects of the consumption of any particular secondary compound (see Foley et al., 1999). According to this hypothesis, the goat would consume its typically mixed diet not *because* of its overall capacity to detoxify secondary compounds, but in order to *avoid* a high intake of any +-----------------------+-----------------------+-----------------------+ | *Without hay | | 73\* | | supplement* | | | | | | | | \% of foraging time | | | | eating: Lentisk | | | +=======================+=======================+=======================+ | | | 12\* | +-----------------------+-----------------------+-----------------------+ | | | 26 | +-----------------------+-----------------------+-----------------------+ | | | 62\* | +-----------------------+-----------------------+-----------------------+ | | | 10 | +-----------------------+-----------------------+-----------------------+ DIGESTIBILITY AND FEED INTAKE ----------------------------- ### Forage Digestion and Intake in Goats FEEDING HOUSED GOATS, SUPPLEMENTARY FEEDING, DROUGHT FEEDING ------------------------------------------------------------ ### Feeding of Housed Goats ### Supplementary Feeding under Field Conditions 1. Substitution rate increases when more forage is avail- able or when forage is of higher quality, or if higher quality supplements are fed, because of associative effects between the digestion of supplement and the digestion of the fiber of the forage. 2. It is usually greater (though not always) if more supple- ment is fed or if the supplement is fed infrequently. 3. For a given quantity and quality of forage on offer, the degree of substitution can be altered by the animals' physiological state. For a given forage base and supple- ment, animals with a higher nutrient demand (such as lactation) will usually exhibit a lower substitution rate. ### Drought Feeding of Goats SUMMARY -------