FAC25-26: Practical Nutrition Flashcards
What are the micro-organisms involved in rumen fermetnation and what is the job of each?
Anaerobic bacteria: cellulolytic enzymes that break down cellulose and hemicellulose into starch and sugar
Protozoa: ferment mainly starch and sugar
Anaerobic fungi
What is normal rumen pH and at what pH are rumen micro-organisms depressed?
normal: 7
depressed: 6
What are the end products of rumen fermentation
VFAs (acetat, butyrate, propionate)
Ammonia
Microbial cells
Gases (methane, CO2)
Name whats to ensure optimum rumen function.
- Rumen pH 6.5-7
- Enough effective long fibre
- Cow comfort and welfare
- Sufficient rumen degradable protein
- Excess highly fermentable energy can disturb rumen function
- Minimise any changes
What is the most important factor in diet formulation?
Dry Matter Intake
What are the cow factors that influence DMI?
- Body weight/ rumen volume
- Milk yield
- Stage of lactation
- Stage of pregnancy
- Body condition score
- Cow comfort
- Rumen health
What are the food factors affecting DMI?
- Digestibility of foods
- Concentrate feeding
- Forages
- Dietary deficiencies
- Palatability
What are the management factors in DMI?
- TMR
- Frequency of presentation of food
- Restriction of access
- Water
- Cow comfort
What is the daily maintenance requirement for Holstein cows?
70-80 MJ of ME
Proportional to bodyweight
What is the production requirements for Holstein cows?
5 MJ of ME per liter of milk
Proportional to Milk Quality and Milk Quantity
Define Metabolisable protein
It is the protein (mixture of amino acids) which the animal has absorbed into its body and is available to meet the needs for maintenance and to produce protein in milk, meat, and fiber
What is Metabolisable protein composed of?
Effective Rumen Degradable Protein and Digestible Undegradable Protein
Why is fiber important in cattle diet?
- Important source of energy for rumen
- Essential to promote rumination
- Formation of rumen mat
- Increases proportion of acetate produce in rumen > increase butterfat levels
- Separate feedstuffs into cellulosic and non-cellulosic feeds
How much water per kg of milk do cows require?
2-3 liters per kg of milk
What is the point of dry cow management?
The dry period is an opportunity for the cow to recuperate and restore resources
Critical for:
- Increased dry matter intake in early lactation
- Reduced disease problems in early lactation
- Increased milk production
How long is the dry period? What are the sub periods and how long does each last?
Dry period = 2 months
Far-off dry period = 2-1 month pre-calving
Near dry period = 2-4 weeks prior to calving
What are the aim of the far off dry period?
Recuperate ater lactation
Get cows in correct condtion score
What are the aims of the near dry period?
Provide cows with best nutrition and environment
What are the repercussions if a cow is too fat or too thin after far-off dry cow management?
Too Fat
- Excess loss of condition score
- Reduced DMI in early lactation
- Health problems
Too Thin
- Poor lactation yields
- Health and reproductive problems
What is the purpose of giving concentrated during near dry cow management?
- Increase energy density of diet
- Acclimatisation of rumen flora to concentrates
- Conditioning of rumen papillae > increase surface area of rumen lining > rapid absorption of VFAs and stable rumen pH
What are the different types of feeds for cows?
Forages
Grazing
Grass silage
Ensiled whole crop cereals (maize silage, whole crop cereals)
Hay
Straw
What is the purpose of long fiber in the cow diet?
To stimulate rumination (scratch factor)
To form floating mat in the rumen
To promote chewing and saliva production
What is the detriment of fine fiber in the cow diet?
Fine fiber > No rumination > Ruminal distension > acidosis
What are the different grazing systems?
Set stocking
Rotational grazing
Strip grazing
Zero grazing (grass brought to cows)
At above what ratio of concentrates to forage does acidosis occur?
If ratio of concentrate to forage in ration exceeds 60:40 on a DM basis, then acidosis may occur
What are the advantages of total mixed ration (TMR)?
Health (feeds mixed together allow for a stable rumen pH)
Maximise Dry Matter intakes
Flexibility in ration formulation (use of cheapest available by-products)
What are the disadvantages of total mixed ration (TMR)?
- Cost of machine and setting up
- Skill required in ration formulation
- Less individual attention to animal
- Some cows become over-fat
- Problems with high concentrate levels
- Works best if cows grouped according to requirements
What is Bovine Somatotrophin (BST)?
It is a recombinant hormone, produced by genetic engineering used to increase milk yeild
What are the advantages of Bovine Somatotrophin?
Increased milk yield by approx 20%
Increased feed efficiency by up to 15%
What are the disadvantages of Bovine Somatotrophin?
- Requires regular administration
- Possible effects on fertility and lameness
- Cost
- Public acceptance
- Not allowed in EU
What determines milk quality?
Butterfat
Protein
Lactose
Why is milk quality important?
Milk price varies according to milk quality
What influences milk quality?
Genes: breed variation, genetic of individuals
Age
Yield/Stage of lactation: dilution effect
Disease: mastitis, liver fluke
What are the nutritional influences on butterfat?
Unstable rumen conditions
- Feed concentrates little and often
- Diet chance
- Sodium bicarb
Provision of adequate fibre
- Quantity and access
- Quality and palatability
- Provision of forage
Dietary Fat
- Saturated “hard” fats to a maximum of 5%
- Unsaturated “soft” fats will depress butterfat
- Protected fats
What is the usual cause of low butterfat levels?
Lack of long fibre in the diet
How is dietary energy related to milk protein?
The major source of milk protein is from microbial protein, the synthesis of which is dependent on dietary energy
What are the nutritional influences on milk protein?
Historical energy status
- Autumn poor nutrition > low winter milk protein
- Monitor via condition scoring and/or metabolic profiles
Forages - maximise energy supply
- Maximise DM intake
- Feed forages with high energy content
Concentrates
- Increase levels of concentrate feeding
- Must avoid ruminal acidosis
- DUP
Dry cow management
- Too fat
- Feeding DUP to help protein intakes
Which is faster to correct: milk protein or milk butterfat?
Butterfat (days)
Protein (months)
What are the risk factors for rumen acidosis?
Cow comfort (poor housing, overcrowding)
Excess carbs
Imbalance of protein: energy ratio
Sudden feed changes
Poor silage or hay
Lack of coarse fiber
What diseases are associated with subclinical acidosis (SARA)?
- Negative energy balance/acetonaemia
- LDA
- Lameness-solar ulcers/white line
- Poor fertility
- Other peri-parturient diseases
How do you diagnose a poor rumen?
Assess ration - amount of long fibre
Asses cows - examine faeces
Production records- milk production, milk quality, disease
Rumen pH
