Animal Nutrition Test 5 Flashcards
How many interactions are known to occur between pairs of minerals (if level of one is increased then digestibility, absorbability, or metabolizability of the other mineral is reduced)?
Over 45
How many mineral elements are required in the diet?
Good evidence for 20, many nutritionist think there’s more. The text says 22, but the specific 22 minerals can’t be nailed down from the reading)
When a mineral in the body has no function it’s called
An innocuous contaminant
Name the macrominerals
Mg2+ Na+ P (PO4) S Cl- Ca2+ K+
Name the microminerals
Si Mo Co Mn Zn Cu Se Cr I F Fe B
Example of mineral involved with hormones
Iodine is a part of the thyroxine hormone, which speeds up the body’s metabolism
Calcium constitutes what percent of bone wet weight?
9%
What percent of all body calcium is found in the bones and teeth? Soft tissues and blood?
99%, 1%
Minerals required for bone lengthening
Ca, P, Mg, F
Which vitamin is necessary for calcium transport across biological membranes?
D
Optimal dietary Ca:P ratios for nonruminants
1:1-2:1
How are fatty acids involved with Ca digestibility?
Fatty acids freed from fat digestion bind Ca, forming an indigestible fatty acid-Ca complex (similar to soap). This reduces Ca digestibility
Ca inhibits absorption of what mineral (besides P)?
Zn
Chronic Ca deficiency symptoms:
Rickets plus acute symptoms. Rickets is a disease of young growing animals which can also be caused by vit D deficiency or P imbalance
Acute Ca deficiency symptoms:
Muscle incoordination (wobbly walks), paralysis, even death. “Big head” disease in horses, various bone disorders
2 other names for calcium tetany
Milk fever
Parturient paresis
What species is milk tetany common in?
Dairy cattle, dogs, sows, and other species
When does milk fever usually occur?
Within the first 5 days after parturition (basically bc milk synthesis depletes the blood of calcium)
Problem with calcitonin and milk tetany
Female absorbs extra Ca during pregnancy and calcitonin helps deposit it in bones. But when lactation starts after giving birth, BLOOD calcium levels drop bc milk needs the calcium. The resulting low blood calcium stimulates parathyroid hormone production, but this is overridden by the calcitonin that is still present so blood can’t be released from bones, until several hours after the calcitonin was produced when it starts being destroyed. Then when the calcitonin is gone the danger of milk fever is gone, is the female lives that long
Modern and old-days treatment of milk fever
Modern: inject Ca, glucose, and Mg. The female will usually recover in less than 30 mins, but another injection may be needed to cure her
Old: reverse milk synthesis mechanism so the milk can be reabsorbed into body. This is done by inflating a cows udder with an air pump and a teat cannula and then sealing the teats with tape
Prevention of milk fever
- feed low calcium diet for 2 weeks before birth to stimulate parathyroid hormone, which will destroy calcitonin
- inject a big dose of vit D within 7 days prior to birth to stimulate extra ca absorption and therefore increase blood calcium levels (caution: if vit D is injected too soon then vit D toxicity, characterized by soft tissue and joint calcification, and milk fever may result)
What is the most versatile element found in livestock? Why?
P, it’s involved in almost every aspect of metabolism
What percent of all body P is found in the bones and teeth? Soft tissues and blood?
80%, 20%
Nearly all cells have P in them
Metabolic functions of P
- P combines with Ca to form crystals that resemble hydroxyapatite crystals, and these are components of hard tissues (therefore it’s indirectly controlled by same hormones as Ca bc it “follows” Ca)
- component of many enzymes (phosphoproteins)
- energy utilization (ATP for example)
- buffer in blood
- protein synthesis (P in RNA and DNA)
- lipid transport and metabolism and cell membrane structure (phospholipids)