Protein Nutrition

Question 1

What are likely the three most limiting essential amino acids?

Answer 1

Lysine, methionine, threonine

Question 2

Name some reasons that protein is important.

Answer 2

Tissue maintenance, production of wool, retention in tissue, milk, growth, gestation

Question 3

How is protein degraded in non-ruminants?

Answer 3

Broken down into smaller peptides by pepsin in the stomach, then moves to small intestine where it is degraded into component AAs by proteases

Question 4

How is dietary crude protein (CP) calculated?

Answer 4

CP = gN/Kg x 6.25, expressed in g/Kg DM

Question 5

What is the formula for protein efficiency ratio (PER)?

Answer 5

PER = LWG (g) / protein intake (g)

Question 6

What is the formula for gross protein value (GPV)?

Answer 6

GPV = LWG (g) per gram of test protein / LWG (g) per gram of test casein

Question 7

What is the formula for biological value (BV)?

Answer 7

BV = [N intake - (Fecal N - Metabolic fecal N) - (Urinary N - Endogenous urinary N)] / [N intake - (Fecal N - Metabolic fecal N)]

Question 8

How do ruminants degrade protein?

Answer 8

Broken down in predigestion by proteases, degraded to NH3 which is utilized by microbes to produce essential and non-essential amino acids

Question 9

What happens if the ruminant does not consume much protein?

Answer 9

Decreases amount of NH3 produced which inhibits microbial growth and carbohydrate digestion/intake

Question 10

How is metabolizable protein (MP) calculated?

Answer 10

MP = Digestible microbial true protein - Digestible undegraded [dietary] protein

Question 11

How can the dietary protein of feed for ruminants be improved?

Answer 11

Heat/aldehyde/tannin treatment, encapsulation of amino acids, bypassing rumen (Esophageal groove), deaminase inhibitors, controlled Maillard reaction (Preventing deamination to preserve protein)

Question 12

What are some dietary sources of protein?

Answer 12

Oilseed meal (Soybean, cottonseed, rapeseed, sunflower seed, oilseed), leguminous seeds/legumes (Beans, peas, clover, alfalfa), animal proteins (Fish meal for pigs/poultry/equids, bone meal which is banned in EU for ruminants, blood meal for farmed fish), non-protein Nitrogen (Urea)

Question 13

How should urea be fed to ruminants?

Answer 13

In small amounts often, less than 1/3 of dietary N, often in mixes with molasses (Both are easily digestible) as opposed to crystals in feed

Question 14

What is associated with NH3 toxicity (Too much urea)?

Answer 14

Bloat, twitching, ataxia, salivation, death