Basics of ruminant nutrition Flashcards
1
Q
What side of the body is the rumen?
A
LHS
2
Q
What are the bugs in the rumen?
A
- 10 billion / ml bacteria
- 1 million / ml protozoa
1 thousand / ml fungi
3
Q
What is the ratio of primary to secondary rumen contractions?
A
2 primary : 1 secondary
(mixing) (belching/regurgitating)
4
Q
What is milk production determined by?
A
- Genetic merit
- Nutrition
- Health
5
Q
What order should be followed when formulating diet?
A
- Dry matter intake
- Energy
- Protein
- Minerals (macro + trace elements)
- Vitamins
6
Q
What activities should be considered with the animal?
A
- Maintenance
- Activity
- Lactation
- Growth
- Pregnancy
7
Q
How much dry matter does a cow need?
A
- Maintenance = 2% - 2.5% BW = 14kg in 700kg cow
- If lactating = more = 3% BW (higher yielding = more)
- If heavily preg = less
8
Q
What influences dry matter intake?
A
- body weight & fatness – “fat cows eat less”
- milk yield “the more she milks the more she eats”
- stage of production cycle e.g. dry cow, calving, fresh calved (all have reduced DMI).
- type of food (digestibility / rate of passage).
- palatability (mixed forages).
- access - feed barrier, electric fence etc.
- availability - TMR versus parlour feed etc.
- social factors e.g. bullying of heifers.
- stress / pain e.g lameness.
- rumen health - “the right bugs & healthy bugs”
9
Q
What are energy foods?
A
- Carbohydrates
- long chain = slow fermentation = fibre (cellulose)
- short chain = fast fermentation = sugars, starches
- Fats
- Protein
10
Q
What does fermentation of carbohydrates produce?
A
- Volatile fatty acids = acetate, butyrate, propionate
- CO2
- CH4
11
Q
What happens to VFA’s?
A
- Absorbed across rumen wall - health of papillae
- Enter krebbs cycle - energy
- Glucose synthesis - from propionate, MILK
12
Q
What is the fate of fats + oils?
A
- Absorbed in small intestine - protected fats
13
Q
All lactating cows in early lactation lose roughly 0.5 - 1 condition score (50kg)
How can you cope with this?
A
- Eat more - increased her DMI
- Metabolise body tissues - fat + muscle
- Reduce milk yield
14
Q
How much energy does a cow need?
A
- Maintenance = 65-70MJ / day
- Production = 5MJ / litre milk
- Pregnancy = only important in last few weeks
- Weight gain/loss = 30MJ/Kg BW
15
Q
What is protein metabolism in cows?
A
- Rumen degradable protein - N containing compounds = fermented to NH4, used by bugs = forms microbial protein
- Rumen undegradable protein = passed through rumen, digested in abomasum + SI (e.g. Soya)
