Grassland

Characteristics and growth

after germination, what are the 3 stages of development

- vegetative
- elongation
- reproductive

Vegetative Stage

leaves develop
- tillers form
- old leaves die off, new grow, therefore high level of carbohydrates

Elongation Stage

stem begins to grow
- inflorescence emerge at top of plant
- level of fibre increase because of stem development

Reproductive Stage

• seed head develops

• stem contains enough fibre to support seed head

• wind pollination occurs

• grass seeds develop

• carbohydrates decreased

Categories of Grassland

Rough mountain and hill grazing

Permanent grassland

Leys

Rough mountain and hill grazing

poor quality
- often acidic
- difficult to cultivate

Permanent Grassland

never ploughed
- perennial ryegrass
- more productive than mountain, less productive than leys
- improved by liming and fertilisation

Leys

field or pasture sown by farmer used for grazing by livestock
- temporary
- reseeded regularly

Stocking rate

the number of animals on a given amount of land over a certain period of time

Rough Mountain/Hill Grazing - Botanical Composition

highly variable
- poorer grasses e.g. bent grasses and fescues

Rough Mountain/Hill Grazing - Stocking Rate

low
- livestock cannot be stocked at a high density bc low nutritional value of grass

Rough Mountain/Hill Grazing - Production Levels

low
- not productive, do not lead to high production levels in livestock

Permanent Grassland - Botanical Composition

variable
- both poor grasses and highly productive grasses like PRG

Permanent Grassland - Stocking Rate

higher stocking rate than rmg due to improved grazing conditions

Permanent Grassland - Production Levels

higher than RMG
- better quality than RMG
- can be improved through liming and fertilisation

Leys - Botanical Composition

one or two species which are sown by the farmer dominate
- e.g. RPG and clover

Leys - Stocking Rate

High
- good quality grassland = ability to support large number of livestock

Leys - Production Levels

high
- best grasses are sown in leys

Important characteristics of grass

palatability
- productivity
- digestability

Palatability

how pleasant the grass is to taste to the animal

cattle and sheep are selective grazers

Most palatable grass

Perennial Rye Grass

Productivity

measure of quantity of herbage produced by the grass

Digestibility

the proportion of food that can be assimilated and used in the body compared to the amount of food consumed

Constituents of Grass

sugar, protein, cellulose, fibre

Growth of Grass - Vegetative Stage - impact on digestibility

enters this stage in spring, after germination
- photosynthesises - large amounts of sugar and starch stored in leaves
- more than 80% of grass digestible (by ruminants)

Growth of Grass - Reproductive Stage - Impact on digestibility

- mid-May, begins to produce flowering stems
- fibre needed to support seed head - produced at expense of protein and cars
- fibre increases = carbs drop by 0.5% per day = decreases in digestibility
- 80% - 50% in 1 month

Dry Matter

content remaining in food sample after water has been removed

dmd

the percentage of dry matter that can be digested and assimilated by and animal

DMI

amount of feed an animal consumes, excluding its water content

advantages of PRG

higher palatability, productivity, and digestibility
- High DM
- long growing season = reduced costs for winter feed