Grazers and Browsers
eat leaves, stems, vegetative parts of plants
includes algae (marine mammals) and lichen
does not include fruit, seeds, nectar, pollen or fungi
forage and browse composition - CP
seasonal
<7% from late winter to early spring
~15-50% in the summer
fluctuates with cell wall content
forage and browse composition- Cell wall content
cell wall content- hemicellulose, cellulose, lignin
>50% in late winter
~30% in mid summer
forage and browse composition- soluble carbohydrates
~40% year round
forage and browse composition- Ash
~5% year round
forage and browse composition- EE
<5% year round
Forage and Browse Accessibility
browse–> leaves, twigs, and other high-growing vegetation
changes with season
- as snow depth increases - may make is easier or harder to reach food
- some herbivores may need to access the forage below the snow
Ash content
minerals are very important in herbivorous diets
- Na, K, Ca, P
- Na, Ca, P may be low in many plants
- K is typically high in most plants
- Na:K and Ca:P may be unbalanced
- want Na:K to be 1:4
- want Ca:P to be 2:1
other sources of Na
road salt
rocks
dirt
artificial salt licks
other sources of Ca
chewing bone
mineral licks
chewing eggshells
dirt
Granivores
dry fruit eating frugivores
- eat cereal grains, nuts, seeds
Cultivated seeds vs weed seeds
low CF vs high CF
high NFE vs low NFE
seed composition
- germ is high in EE
- endosperm is high in NFE
- husk is high in CF
Phorphorous availability
some P stored as phytate in seeds
- mostly concentrated in the husk
- reduces digestibility off other nutrients (CHO, CP, EE)
- plant phytases turn phytate into available P when seeds sprout
Mycophages
fungi eating animals fungi are 75% water CP is 60-80 unavailable --> mostly NPN lots of NDF- lots of cell wall BAd Ca:P