Animal nutrition - minerals & vitamins Flashcards
True digestibility of calcium
20-55%
how much is too much Ca for cattle
over15 g/kg ration DM
PTH function
increases serum Ca by,
Release of calcium from bones.
Absorption of calcium from the intestines.
Conservation of calcium by the kidneys.
calcitonin function
(synthesised by the parafollicular cells of the thyroid and counteracts PTH)
descrease serum Ca by,
Major effect: inhibits osteoclastic bone resorption
Minor effect: Inhibits renal tubular cell reabsorption of Ca2+ and phosphate
1,25-dihydroxycholecalciferol function
or vitamin D3, also known as calcitriol (synthesised in the cells of the proximal tubule of the nephron)
increases serum Ca by,
Promotes absorption of dietary Ca from the GI tract.
Increases renal tubular reabsorption of Ca
Stimulates release of calcium from bone.
osteomalacia
is softening of the bones, bone fragility
vitamin D and/or calcium deficiency can cause this
what part of plants typically contain most calcium?
Ca content is higher in the vegetative parts of plants (so teh leafy, green parts), compared to the seeds and roots
give 3 examples of sources of Ca among legume plants
clover, lucerne, peas
True digestibility of phosphorus
60-90%
absorption takes place in the lower parts of the small
intestine (both pigs and ruminants)
Ca excess does what to P absorption and storage into tissues
decreases it
Optimum Ca : P ratio in an animals’ ration is
dry cow 1.3 - 1.4 : 1
milking cow 2 : 1
signs of P excess
– causes deficiency of Ca
– stimulates PTH, which in turn stimulates Ca resorption from bones, leading to bone demineralisation
signs of P deficit
– long-term deficit causes bone fragility
– ambiguous signs: animal appetite is reduced, growth slows down, milk production is reduced, animal is sluggish
what part of plants typically contain most phosphorus?
generative parts of plants meaning the seeds and seed hulls
what is the biggest significance of Se
The biggest significance of Selenium is in the composition of the enzyme glutathione peroxidase, which is strongly associated with vitamin E and with other antioxidants
how does sulphur affect selenium?
significance in the ratio between Se and S (cell entry competition for the same carrier)
i.e. S is an antagonist to Se
-> high S amounts leads to higher Se excretion via urine
what is alkali disease
Chronic selenium poisoning
when the ration Se content is > 5 mg/kg DM
emaciation, hair loss (horsehair mane and tail), hoof and claw anomalies, swollen joints, lameness, anaemia, growth retardation in young animals, etc.
what is blind staggers
Acute selenium poisoning
disorders of the central nervous system and coordination of movement, hoof and claw growth anomalies, deformation of joints, lameness, paralysis, deformities, etc.
The metabolism of Selenium and what vitamin is very closely connected
vitamin E
what is Beriberi disease
what vitamin deficiency is involved?
a polyneuritic syndrome
Beriberi is a deficiency of thiamin, more commonly known as vitamin B1.
what vitamin deficiency is involved in the development of rickets?
vitamin D
in conjunction with inadequate sun exposure (+ lack of Ca and P)
fish liver oil still heals rickets after the vitamin A is degraded by oxidation
what vitamin deficiency is involved in the development of scurvy?
vitamin C
what vitamin deficiency is involved in the development of night blindness?
vitamin A
one retinol derivative is part of the composition of the
light-sensitive eye pigment rhodopsin
how does beta carotene relate to vitamin requirements?
Beta carotene is a provitamin A carotenoid, or a nutrient that the body readily converts into vitamin A.
Fat-soluble vitamins (min 4)
A, D, E, K
A1– retinol, retinal, retinoic acid
A2- dehydroretinol
D2– ergocalciferol
D3– cholecalciferol
E – tocopherol, tocotrienols
K1– phylloquinone
K2– menaquinone
K3– menadione (synthetic form is water soluble)
Water-soluble vitamins
the B-vitamins and vitamin C
B1– thiamine
B2– riboflavin
B3 - niacin, nicotinic acid
B4 - Choline/adenine
B5 - Pantothenic acid
B6– pyridoxine, pyridoxamine, pyridoxal
B7 - Biotin
B8 - Myo-inositol (synthesised in human body)
B9 - Folic acid
B12 – cobalamin
what mineral competes with selenium for absorption?
sulphur
cell entry competition for the same carrier i.e. S is an antagonist to Se -> high Sulphur
amounts leads to higher Selenium excretion via urine
potassium
functions and feed sources
- maintain water balance
- maintain osmotic pressure
- maintain acid-base balance
- activate enzymes
- help metabolize carbohydrates and proteins
- regulate neuromuscular activity (along with Ca)
primary source of potassium is the forage portion of the normal ruminant diet
wheat/corn and soybean meal diets
potassium
deficiency symptoms and associated problems
Potassium deficiency may commonly be manifested by
depressed growth, muscular weakness, stiffness, decreased feed intake, intracellular
acidosis, nervous disorders, reduced heart rate, and abnormal electrocardiograms.
sodium
functions and feed sources
major extracellular cation and essential for maintaining osmotic pressure in the body as well as water regulation. is essential for transporting nutrients around the body and removing waste from cells.
Sodium is found in forage
sodium
deficiency symptoms and associated problems
Sodium deficiency in ruminants can cause reduced appetite, reduced water intake, weight loss, reduced milk production and pica.