Nutrition - Livestock Flashcards
(42 cards)
What are the main requirements for livestock nutrition?
- Animals must have enough nutrients to maintain metabolic processes and locomotion.
- Animals need sufficient nutrients to maintain production (meat/ milk/ wool/ lactation etc)
What are the two main components of food?
- Water
- Dry matter
What are the 5 main macronutrients?
- Carbohydrates
- Fat
- Energy
- Protein
- Minerals
Why do we need to measure the nutrient composition in feeds?
- To determine the variation between feeds
- To prevent under/ over nutrition
- To formulate the correct feed ration
What is dry matter?
The mass of food remaining after all the water has been removed.
How is dry matter obtained?
- Food is dried in an oven at 60-100 degrees
- OR food is freeze dried (lyophilisation)
What are the key components of plant cell walls?
- CHO chains - hemicellulose, cellulose, lignin
- Water soluble carbohydrates - starch, sugars, pectin.
What are essential amino acids?
- Amino acids that cannot be synthesised in vivo (so must be provided in the diet)
What are two of the main essential amino acids for cats and dogs?
- Arginine essential for dogs and cats
- Taurine essential for cats
What are conditionally essential amino acids?
- Amino acids that cannot be synthesised at a fast enough rate (under certain conditions)
What are non-essential amino acids?
- Amino acids that can be synthesised in vivo
How do we measure the amount of crude protein in a food sample?
Must measure the amount of nitrogen present.
Give a simple overview of how crude protein is obtained
Using the Kjendal N method
1) Digestion (boiled with acid)
2) Distillation (NaOH, boric acid used)
3) Titration (titrated with acid to quantify the ammonia)
Why are fats and oils needed in feed stuffs?
- They are carriers of vitamins A, D, E and K
- They are high energy
- They reduce dust in pelleted feeds
- They help with binding for pelleted feeds
- They improve palatability of some foods
How do we measure the amount of fat in feed?
Using an ether extract process under reflux conditions.
What are the limitations of removing fat this way?
- You cannot distinguish what the different fats and oils are in a sample
- Only determines the fats that can be extracted by that particular solvent
What is the difference between monosaccharides, disaccharides, digosaccharides and polysaccharides.
- Monosaccharides = 1 sugar unit
- Disaccharides = 2 sugar units
- Digosaccharides = Several sugar units
- Polysaccharides = Many monosaccharide units
Describe the structure of cellulose found in plant cell walls.
- Linear chain of beta-D-glucose units linked by beta-1.4 glycosidic bonds
What is the difference between ruminants and non-ruminants in terms of cellulose breakdown?
- Cellulose is indigestible in non-ruminants as it cannot be digested by mammalian enzymes
- Cellulose can be digested by ruminants as rumen microorganisms can degrade and ferment it.
Where is lignin found?
Lignin found in the stems and trunks of plants.
Can lignin be digested?
- Lignin is resistant to degradation by mammalian and microbial enzymes.
- Anaerobic fungi in the rumen microbiome are thought to be able to modify the structure of lignin.
How do we measure the amount of fibre in feed?
1) Take a sample post fat extraction
2) Boil in acid
3) Boil in alkali
4) The residual feed contains cellulose, hemicellulose and lignin.
What are the imitations of measuring fibre in this way?
- Cannot distinguish between the different types of fibre.
- Often gives an under estimation due to soluble fibre components.
What does NDF stand for?
Neutral detergent fibre
