LECTURE 29- Livestock production systems III: pastoral livestock production

what happens to grass quality as it grows

• Leaves start to die as grass reaches a certain maturity

• Main stem solidifies with fibers and seed head grows

• Grass growth eventually stops growing and the grass dies, leaving the dry seedhead

what happens to grass nutritive value as it grows

• grass is 75-80% digestable when actively growing

• fibre accumulates as grass matures, and makes digestibility harder

• becomes less nutritive due to fibre and seedheads

What influences pasture supply?

• Rainfall and temperature

• Previous grazing

• Types of pasture

• Seasonal things

What influences pasture/animal demand?

• animal’s energy requirements

• Animal activity/production

• Environmental temperature

What influences animal energy requirements

Maintenance and lactation (also growth and pregnancy)

what species are seasonal breeding animals

• sheep

• goats

• deer

• horses

what animals are non-seasonal breeders

• Cattle

• Pigs

• Poultry

why are cattle treated as seasonal animals in NZ

 so that lactation can align with spring pasture growth (to meet energy demands)

what is seasonal sheep production like

spring: lambing and lactation

summer: lambs weaned off mothers and given supplementary feed

autumn: mating season

winter: ewes pregnant over winter

what is seasonal dairy cattle production like

spring: calving and early lactations, cows are bred

summer: middle of lactation

autumn: late lactation

winter: cows are dried off in preparation for calving

how is pasture mass measured

pre- and post-grazing pasture mass/cover (kg DM/ha)

what is the pre-grazing pasture target for sheep

1100 to 1500 kgDM/ha

what is the post-grazing pasture target for sheep

 800 to 1000 kg DM/ha

what is the pre-grazing pasture target for dairy cows

1900 to 2100 kgDM/ha

what is the post-grazing pasture target for dairy cows

1500 to 1600 kg DM/ha

whats the purpise of grazin targets

Targets helps to optimise intake efficiency

what happens if pasture gets too long

 pasture growth is slow with a decrease in quality, and pasture death with dead matter occurs

what happens if pasture gets too short

pasture regrowth will be small because of not enough leaf. Grazing too low restricts intake