Bovine Nutrition Flashcards
What is ERDP? Give an example
Effective rumen-degrading protein eg urea
What is FME? Give an example
Fermentable metabolisable energy ie starches and sugars
What is RUDP?
Undegradable rumen protein
Digested in abomasum and small intestine
eg soya
High quality, expensive
How much protein does a dairy cow require?
16% if yield < 8000L
18% if yield > 8000L
How much protein is in grass silage?
12-18%
What is ME?
Metabolisable energy
Energy available to animal for maintenance, growth, lactation and pregnancy
What is the capacity of the rumen?
200L +
What are carbohydrates fermented to?
Volatile fatty acids (acetate, butyrate, propionate)
CO2
Methane
What happens to VFAs in the rumen?
Absorbed across rumen wall
Enter Krebbs cyce
Glucose synthesis (from propionate)
How much does a ruminant eat?
2-2.5% BW if doing nothing
If lactating: 3% BW if producing 30L/day, 4% BW if producing 50L/day
If heavily pregnant, eats less as foetus occupies space in abdomen
Give some factors that influence DMI
Body weight and fatness (fat suppresses appetite) Milk yield Stage of production cycle Type of food (digestibility) Palatability Access to feed Availability (TMR vs parlour feed etc) Social factors eg bullying Stress/pain eg lameness Rumen health
When do cows ruminate best?
When lying down
How much energy does a cow require for maintenance?
65-70MJ
+ 5MJ/litre of milk
What are ghrelins?
Hormones involved in appetite
When is milk yield highest?
8 weeks after calving
What DMI should you aim for at peak milk yield?
4% (appetite)
What M/D values should lactating, dry and cows at pasture be fed?
Lactating cows: 11.5-12.3 MJ ME/kg DM
Dry cows: 8-8.5 MJ ME/kg DM
Cows at pasture: no more than 14 MJ ME/kg DM
What are the DM and M/D values for clamp grass silage?
DM: 20-35%
M/D: 10-12 MJ ME/Kg DM
What are the DM and M/D values for maize silage?
DM: 30-35%
M/D: 11-11.5 MJ ME/Kg DM
(High starch so fast fermenting, low protein, poor fibre source)
What are the DM and M/D values for big bale silage?
DM: 30-35%
M/D: 8.5-10.5 MJ ME/Kg DM
What are the DM and M/D values for hay?
DM: 85%
M/D: 8-9 MJ ME/Kg DM
What are the DM and M/D values for straw?
DM: 85%
M/D: 5.5-6.5 MJ ME/Kg DM
What are the DM and M/D values for grass?
DM: 20% or less
M/D: 10-12.5 MJ ME/Kg DM
What are the DM and M/D values for concentrates/cake?
DM: very dry!
M/D: 12.5 MJ ME/Kg as fed
Where do cows get most of their vitamins from?
Rumen bacteria
What are the management aims during the dry period?
Avoid getting fat
Rest period
Mammary regeneration
Rumen development (suitable bugs for post-calving diet, big and muscular, big healthy papillae for good absorption
How long is the dry period?
60 days
What happens to DMI during the dry period?
Decreases, therefore good to get cows eating as soon as they calve
What kind of diet should you feed during the dry period?
Lasts 8 weeks:
5 weeks: Low energy/high fibre diet
3 weeks: ‘transition diet’
Should also pay attention to the 3 weeks after calving
What DMI should a cow have in the early dry period?
10-14kg
How much M/D energy should a cow be getting in the early dry period?
What kind of diet should this be?
7.5-8.5 MJ/day (low energy)
High fibre for rumen health
Why should you not feed too much energy in early lactation?
Suppresses appetite
Predisposes to metabolic disease in lactation (‘fatty liver’, diabetes)
How much energy does a cow need in a transition diet?
What about M/D value?
110-120 MJ/day
M/D: 9.5-10 MJ ME/Kg DM
How much crude protein does a cow need in a transition diet?
13-15%
Keeping many cows on a small patch of grass is a risk factor for what?
Strep uberis mastitis
What should you feed in a transition diet?
Silage and straw and 2-2.5kg dry cow concentrate
When should you move a dry cow to a calving pen?
Early 2nd stage of labour
How much feed barrier space should a cow have?
At least 90cm/cow
Is it better for a cow to be fat or thin before calving?
Why?
Thin
Fat cows lose more BCS in early lactation, and have smaller increases in milk yield
Fat cows before calving become thin cows after calving
When does most metabolic disease occur?
In the first 10-12 weeks of lactation
Give some problems that can occur in cows after calving
Ketosis Milk fever (hypocalcaemia) RFM/metritis/endometritis Mastitis Displaced abomasum Fertility problems Lameness
What happens to DMI during gestation?
Decreases
What DMI should you aim for in the dry period?
12-14kg
What is a ‘far off diet’?
Early dry period diet
Silage plus straw
When is a cow’s peak DMI?
4-10 weeks post-calving
What is the ‘keenan diet’?
One diet for the whole dry period
Low energy (95-100 MJ/day, 12-13 kg DMI, M/D 8-8.5)
Include chopped straw
