Protein and Energy Imblanace Ruminants

Question 1

What chop length should fibre in the diet be?

Answer 1

2-4cm - optimum scratch factor to stimulate rumenal movements

Question 2

How long should a cow spend lying down per day?

Answer 2

14 hours

Question 3

What is the drop test?

Answer 3

Drop to knees on cubicle - see how comfortable it is

Question 4

What is the CCI?

Answer 4

Cow Comfrot Index = No. cows lying down ruminating 1hr prior to feeding
- should be at least 60%, 85% best

Question 5

WHy may the feed a cow intake be different than the prescribed diet?

Answer 5

Palatability of diet

Distribution between cows - space

Question 6

How much head space should each cow have at a trough?

Answer 6

60cm

Question 7

What trough factos may influence food intake?

Answer 7

Physical condition - sharp edgers

Clean - old food should not be left under fresh!

Question 8

How does cow behaviour affect drinking troughs?

Answer 8

• Should be enough space for group of cows to drink together - social animals
• check floor surrounding trough - can they access it?

Question 9

What is TDS?

Answer 9

Total dissolved solids ?? CHECL

Question 10

Should DMI be estimated or measured?

Answer 10

> Measured - estimates often innacurate
DMI for all foods (inc. oils etc.) should be incorporated
Squeeze silage - if water comes out >20% water content

Question 11

How may required DMI be calculated in lactating cows?

Answer 11

DMI = 2.5% BW + 10% milk yield

[estimate only]

Question 12

Why may analysis of feed components be inaccurate?

Answer 12

• analysis inaccurate
• sample not representatice (levels of silage clamp, no. of g rass cuts)
• when sample taken

Question 13

What is true TMR? How do majority of systems differ?

Answer 13

Everything fed in total mixed ration

- majority of dairy herds fed some concentrates in the parlour too

Question 14

What may moulds in the silage produce?

Answer 14

Mycotoxins

Question 15

Is self feed silage a good ide?

Answer 15

No - if silage sufficiently tightly packed to protect from spoilage then cows will not be able to eat it.
- often usd in conjunction with an electric fence -> stress -> v food intake

Question 16

What problems may grazing grass present?

Answer 16

• overestimate energy value of grazed grass esp. in long dry summer (stemmy fibrous grasses)
• bloat from clover rich pastures
• Mg deficiency (grass staggers)
• over eating lush pasture or grains -> bloat/acidosis

Question 17

How can overeating at pasture be prevented?

Answer 17

Buffer feed - silage, hay or TMR to supplement grass before turning out

Question 18

What level should milk fat be at? What is this proportional to and may cause this to drop?

Answer 18

4. 2%
   - proportional to fibre level in diet
   - if concentrate:forage ratio >60:40 will drop significantly (as acetate levels drop and propionate levels ^)
   - spring grass low in fibre -> v milk fat
   - Low bulk tank milk fat: SARA (but differnet groups within herd likely to differ significantly and counteract this affect/hide low milk fat cows)

Question 19

What level should milk protein be at? When may this drop and is it easy to correct?

Answer 19

3. 4%
   - drops after inadequate energy intake
   - very difficult to correct quicjly

Question 20

How is dung scored? How is optimum dung recognisable?

Answer 20

1 - 5, 1 loose and watery, 5 stiff and dry

3 optuimum - sounds like slow hand clap

Question 21

How can BCS be used to assess feeding?

Answer 21

Compare cows in different stages of life cycle

• dry
• freshly calved (early lac)
• 2.4 weeks post calve (mid lac)
• late lac

Question 22

What is the optimum BCS for a cow to calve at?

Answer 22

2.5-3

Question 23

What is the most important stage of lactation to look at? Why? What BCS should they start/finish at?

Answer 23

Dry cows
- critical 6 weeks either side of calving
- problems here ->
> poor DMI post calve
> metabolic disease
> poor milk production
> poor fert
- SHOULD NOT LOSE WEIGHT DURING THE DRY PERIOD, will lead to fatty liver and metabolic problems
- Should be dried off at same BCS they will calve at (~3)

Question 24

How should dry cows be divided?

Answer 24

1. Dry off - 14d pre calving [far off or early dry group]
2. 14d pre calving -> calving [transition or close up cows] In this group diet similar to that they will receive post calving to allow gradual rumen changes

Question 25

What are metabolic profiles and how may they be used?

Answer 25

• planned regular blood tests (4x year) on 6 cows from each of 3 groups (early 10-20d post calve, mid 100-200d, drys within 14d of calving)
  > spring turn out to grass
  > mid/late summer (pasture qulatiy variable)
  > housing
  > late in winter housing
  + whenever major diet change implemented
• objective indication of how well cows are handling diet
• do NOT sample sick cows!!!
• include heifers
• always WAIT 10d after change