Ruminant Feeding Systems

Question 1

What are the main challenges in a pasture-based ruminant production system?

Answer 1

Seasonality of growth and pasture quality

Question 2

Why are pastures important in ruminant feeding systems?

Answer 2

Grow year round
Animals harvest their own feed
Cheap source of feed

Question 3

How do changes in pasture quality impact animal performance?

Answer 3

higher quality means more nutritious
need to account for energy needed for growth, pregnancy, reproduction, lactation, and body condition score
lower quality lowers production

Question 4

How is feed quality measured in ruminant systems?

Answer 4

digestibility (%)
metabolizable energy (ME)
protein content (%)

Question 5

What management strategies could a farmer use to cope with variations in pasture growth?

Answer 5

have a high enough stocking rate to use pasture efficiently
timing (calving/lambing, weaning, sales, and drying off)
rotational grazing
supplementation
off-feeding
culling

Question 6

what are the biological processes in ruminants

Answer 6

maintenance
lactation
reproduction
liveweight gain (growth or body condition score)
activity
wool/fibre growth

Question 7

What factors influence the energy requirements for liveweight gain?

Answer 7

proportion of fat and protein laid down

Question 8

What factors influence the energy requirements for pregnancy?

Answer 8

birthweight
number of offspring
stage of pregnancy
(includes growth of fetus AND placenta)

Question 9

What factors influence the energy requirements for lactation?

Answer 9

volume and composition (fat, protein, and lactose)

Question 10

How can efficiency of production be measured?

Answer 10

animal basis (liveweight, milk solids)
per kg DM eaten
using financial metrics

Question 11

Why is a twin bearing ewe more efficient than a single-bearing ewe?

Answer 11

Less feed intake per lamb weight, but still close in growth to single lamb for weaning weight

Question 12

What factors can limit feed intake?

Answer 12

low quality diets (physically can’t consume enough feed to meet demands)
late pregnancy (fetus takes up abdomen and rumen space)
early lactation (multiple babies means higher requirements for lactation)

Question 13

What are the two equations to calculate efficiency of lactation?

Answer 13

kg MS/kg liveweight
kg MS/kg feed eaten

Question 14

Aside from ME, what else is needed for most biological processes?

Answer 14

Metabolizable protein (MP)

Question 15

How does body condition score contribute to animal intake?

Answer 15

Nutrients from tissue turnover (fat and protein) contribute to meeting nutrient requirements
animals will low BCS may be moved to be fed more or less by farmers

Question 16

How can selection by the animal influence feed intake?

Answer 16

will avoid stems and dead matter
search for their preference
won’t eat something they dislike
may graze too low then lower pasture quality

Question 17

What is selection by the animal influenced by?

Answer 17

palatability
aversion
nutrient needs
availability
age/experience
competition
species

Question 18

What parts/types of plant do sheep & cows prefer?

Answer 18

clover and grass

Question 19

What parts/types of plant do goats prefer?

Answer 19

grass, weeds, & browse
avoid clover

Question 20

What parts/types of plant do deer prefer?

Answer 20

forage and browse with low fibre

Question 21

Does selection differ between young and mature animals?

Answer 21

Yes;
young animals still need to learn to graze new feeds
different stages of growth have different nutritional requirements, so they will prefer different kinds of feed

Question 22

What is the common pasture mass for ewes?

Answer 22

800-1200 kg DM/ha (2-4 cm)

Question 23

What is the common pasture mass for dairy cows?

Answer 23

1800-2200 kg DM/ha

Question 24

What is the purpose of pasture mass targets?

Answer 24

ensures animals are well fed
ensures the pasture will regrow as fast as possible
peak photosynthesis during grazing

Question 25

How does intensive grazing impact sward quality?

Answer 25

minimizes stem encourages grass and clover growth restricts maximum intake essential for successful and profitable use of pasture

Question 26

How does lax grazing impact sward quality?

Answer 26

suppresses clover growth increases stem and dead matter reduces digestibility increases work to chew forage (lowers rate of digestion and lowers intake)

Question 27

When do ruminants graze?

Answer 27

in the mornings late afternoon before sunset

Question 28

What feed is preferred by ruminants during afternoon grazing? Why?

Answer 28

grass; higher bulk and slower to digest, fills the rumen overnight to reduce the need for grazing

Question 29

What are the three levels of feed planning?

Answer 29

strategic (long term) tactical (few weeks to several months) operational (daily)

Question 30

What is the cheapest feed for ruminants?

Answer 30

pasture; alternative feeds are more costly

Question 31

What is the equation for the average number of clicks in a paddock from the plate meter calculation?

Answer 31

(B - A)/C (end - start)/number of drops (usually 30-50)

Question 32

What is the equation for kg DM/ha in the paddock for *sheep*? (plate meter calculations)

Answer 32

158 x average clicks + 200

Question 33

What is the equation for kg DM/ha in the paddock for *dairy*? (plate meter calculations)

Answer 33

149 x average clicks + 500

Question 34

what factors influence maintenance costs?

Answer 34

species liveweight sex age grazing environment topography climate feed quality physiological state