From feed to milk
40 important questions on From feed to milk
What are the two main feedstuffs?
- mainly vegetative plant parts (leaves, stems) (e.g. grass or mais)
Concentrate feedstuffs
- mainly reproductive plant parts (seeds)
What are the characteristics of roughages
- Relatively low dry-matter content
- Relatively high fibre / cell-wall content
- Relatively low digestibility
What are the characteristics of concentrate feedstuffs
- High in energy, protein and digestibility
- Low in water and fibre
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What are the two types of roughages?
- Grazed forage (graasvoer)
- cut forage (snij voer)
Conserved roughage
- Silage (kuilvoer)
- Hay (hooi)
- Artificially dried roughage (bales, pellets) (kunstmatig gedroogd ruwvoer)
Give some aspects of high-quality roughage
- a high-quality source for nutrients
- essential for the rumen microbes
- essential for rumination
- regulating rumen pH
- allowing a high milk yield
Forage is the cheapest feed source
- especially true for grazed forage
What are the main forages (=voedergewassen)?
- Grasses
- legumes
- other herbs
(rangelands)
- tree leaves
- crop residues
- by-products
Concentrates come in two forms and compose of a wide range of ingredients. What are they
- Grains
- By-products of the food industry
- Premixes with vitamins and minerals
What are the characteristics of fodder crops and what is their growth pattern?
- Often annual
- cultivation on arable land
species
- Forage maize
- Fodder beet
- Lucerne (alfalfa)
What do you know about Grassland species?
- Forages are edible plant species present in grasslands
- grasses (Poaceae or Gramineae)
- Legumes (Fabaceae or Leguminosae)
- Forbs (non-leguminous herbs; many species from different plant families)
For grass species mixtures are used in temperate climates including:
- Perennial ryegrass (Lolium perenne; Engels raaigras)
- Timothy (Phleum pratense; timothee)
- Meadow fescue (Festuca pratensis; beemdlangbloem)
- Others, e.g. Smooth-stalker meadowgrass (Poa pratensis; veldbeemdgras)
There are two types of clovers
- White clover
- (Trifolium repens, witte klaver)
- in mixtures for grazed grasslands
- Red clover
- (Trifolium pratense, rode klaver)
- Mainly for cut grasslands
What is the availability of the forage?
- Due to seasonal production patterns, fresh forage is not always available
- There is no fresh grass during winter in temperate zones, in other areas there is no fresh grass during the dry season
- A solution is to provide other feed (e.g. Fodder crops or more concentrates) or to conserve surplus forage and store it
- other solutions....?
What is the aim and method of preservation-conservation
Method: stop activity of plant enzymes and of micro-organisms to prevent decay
different methods:
- Drying
- Acidification (ph verlagen
- Freezing
- Etc.
- ph verhogen
What is ensiling - silage making
- Fermentation of sugars by anaerobic bacteria
- Lactic acid
- Acetic acid
- Propionic acid
- Classified based on moisture level
- High moisture silage (>70% moisture)
- Wilted silage (60-70% moisture)
- Haylage or low-moisture silage (40-60% moisture)
How are the positive microorganisms playing a rol in ensiling
- Strong pH decline- acidification
- Lactic acid as end product
Enterobacteria
- Less strong pH decline
- Have acetic acid as end product
- Compete for sugars; increase buffering capacity; produce CO2 (energy loss)
How are the negative microorganisms playing a role in ensiling
- Ferment sugars, organic acids and proteins (including their amino acids and amides)
- Increase dry-matter losses (produce NH3 and CO2)
- Produce butyric acid, which has a pungent odour and makes silage unpalatable for animals
- Ammonia increases pH, which allows other undesirable micro-organism to proliferate
Fungi
- Yeasts
- Moulds
Protein in the forages (what do you know)
- 75% of the N in fresh forages is protein
- In silage, only 20% of the N may be protein
- Proteases break down protein to non-protein N forms, such as peptides, amino acids, amides, amines and ammonia (NH3)
Bacterial spores can end up in cheese, how does this develop?
- Bacterial spores, resulting form silage making, can enter the milk
- If milk contains spores of butyric acid bacteria, there is a problem with cheese making
- Especially Edam, Gouda, Parmesan and Emmenthal cheese are very susceptible (=vatbaar) to spores
- Therefor in som regions it is not allowed to feed silage to cows, whose milk is used for precessing these cheeses
Ration effects on flavour(, why, how)?
- Apart from the well-known effect of certain specific plant species (like cabbage, garlic, onion) on milk or cheese of-flavours, the specific effect of the floristic composition of the grass has been relatively poorly studied
- The composition of a ration consumed by a ruminant can have a marked influence on the composition, appearance and sensory characteristics of milk and meat and there products
Protected designation of origin (PDO) =
Botanical diversity could be associated with more diversified and numerous cheese aroma attributes
What kind of contaminations of milk through the feed are there?
- Grass, often home-grown
- Maize, either home-grown or bought in the local market
- Concentrates and by-products, bought or obtained through feed-manufacturing companies
Contaminants may include
- pesticide residues
- Polychlorinated biphenyls and dioxins
- Mycotoxins
- Heavy metals and radionuclides
What happens with the pesticide residues?
- The problem has drastically decreased since the ban on persistent organochlorines. These substances are lipophilic and therefore tended to accumulate in the milk
- Other pesticides are completely broken down by the cow, in contrast with persistent organochlores used in the past
- in grassland management and forage production, pesticide use limited compared with food production.
Feeding value encompasses:
- Composition of nutrients in the forage
- Ability of the animal to utilise these nutrients (i.e. Efficiency of conversion of ingested nutrients into body tissue or milk)
- Amount of forage the animal will eat
- Feeding value = nutrient intake x food conversion efficiency
- Nutrient intake = herbage intake x nutrient concentration
There is a diet selection; what are the diets eaten by grazing animals?
- Higher proportions of leafy material
- Less stem and dead material
- Preference and selection for specific species
Therefore higher nutritive value with grazing than with stall feeding (cut and carry)
What is a normal intake by the cow?
- 25% of her live wight of fresh herbage per day
- i.e. 12-16 kg of herbage dry matter
- i.e. A volume of 1 m3
- Herbage dispersed over an area of 100-500m2
The intake of water by the cow
- Herbage contains water and dry matter
- A highly productive dairy cow may need more than 100 L of water per day
- Free access to fresh water is essential for milk production: 87% of milk is H2O
Water is also needed for vital body functions including
- Regulation of body temperature
- Digestion
- Metabolism
- Excretion
- Blood volume
Water from fresh forage
- 70-80% of fresh forage is water
External
- Rain
- Dew
Daily requirements of a dairy cow: 30-130 litres of H2O
Where does dry matter exist of
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
Inorganic matter (ash)
- Minerals
- Sand
Mass concentrations expressed in g per kg dry matter
What kind of vitamins are in herbage?
- Water-soluble
- 9 B-complex vitamines
- Vitamin C
- Fat-soluble
- beta-carotene or provitamin A
- Vitamin D2, D3
- Vitamin E
- Vitamin K
Forages are rich in fat-soluble vitamins
Vitamin E is high in fresh grass but low in conserved or dried forages
When do mineral deficiencies occur?
- Tropical grasses can have low concentrations of minerals resulting in deficiencies and disorders in the animal
- Important macro-minerals for dairy cows are: Ca, P, Mg, Na, Cl, S and K
- Important micro-minerals include: Fe, Cu, Mn, Zn, I, Co and Se
What is the positive effect of secondary metabolites on the animal?
- Sustainable control of internal parasites (chicory, sulla)
- Enhancing reproduction in sheep
- Reducing bloat risk in cattle (lotus, sulla)
- Reducing methane production to combat greenhouse gas emissions (chicory, sulla)
What is the negative effect of secondary metabolites on the animal?
- Tannins are naturally occurring polyphenolic compounds
- condensed tannins (CT) are the most common type found in forage legumes, trees and shrubs
- CTs lower palatability, voluntary intake and digestibility
- However, tanniferous herbage might enhance ruminant productivity (improved protein supply, boat safety) and health (anti-parasitic properties)
What kind of animal health problems are there (waneer we naar voedsel kijken)
- Mineral deficiencies
- Direct poisoning (e.g. Oxalates, syanide, alkaloids, amino acids)
- Secondary poisoning (e.g. Photosensitivity)
- Fertility problems (e.g. Oestrogenic isoflavones)
- Ohter (e.g. Bloat)
What is the crude protein content in
Grass (poorly fertilised)
Grass (highly fertilised)
White clover
Maize silage
- Grass (poorly fertilised)
- 100-150 (g kg DM-1)
- Grass (highly fertilised)
- 250-300 (g kg DM-1)
- White clover
- 200-250 (g kg DM-1)
- Maize silage
- 70-80 (g kg DM-1)
Carbohydrates are the largest energy source for herbivores. 50-80% of the total fry matter is carbohydrate. Which two types of carbohydrates are there?
- Hemicellulose
- Cellulose
- Lignin
Non-structural carbohydrates
- Sugars (e.g. Glucose, fructose, sucrose)
- Storage compounds, such as starch
Structural carbohydrates - fibre are
- Encompass cell wall material
- Provide structure and strength to the plant
- Increase with maturity
- Are indigestible for monogastric animals
Ruminants can digest fibre
- Symbiosis with microorganisms
- Rumination
Energy value of forages
- loss as faeces energy
- Loss as methane enegery and bring energy
- Loss as heat associated with the work of digestion, absorption and metabolism of nutrients
The Net energy will remain
- for maintenance of body function, accumulation of body tissue, and lactation
What are the factor influencing the chemical composition and digestibility?
- Species
- Maturity
- Climate/weather
- Breeding
- Management
C3 versus C4 plants
- Tropical grasses (C4) more lignified
- 2 step approach
- Temperate species (C3) better digestible
- 1 step approach
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