What are the assumptions when conducting a C-N balance experiment?
- When conducting this experiment we tend to measure input/output.
- There are % of nutrient levels that help determine the level of C-N levels.
- The body has 52.5% protein, 76.5% fat, glycogen will also be ignored.
- Fat= 9.4 Kcal/g energy
- Protein= 5.7 Kcal/g energy
Briefly explain how you experimentally determine NEm. How does this compare to the estimation of NEm?
Experimentally determine NEm -> controlled point for ration in animal (not gaining or losing wt)
Once reaching this point -> measure all inputs (rations nutritional facts - output)
Outputs= fecal, urinary, heat, etc
We can figure out the animals maintenance requirements. This is much better estimation which would be based on the animals size.
Name all the factors that affect heat production and explain two in detail
Factors that affect heat prod: gender, age, size, exercise, environmental conditions, ration, GI tract, intake, season ,etc.
Exercise- friction and prod needed to produce ATP. The harder the animal exercises the more heat prod
Nutrition/ration- rumen breaks down starch and fibers which causes heat to be produced. More concentrates= more heat produced
Name three methods of measuring heat production (HP) and then define one of them you know best
Calorimetry- Direct: sensible heat (radiation, conviction, conduction), evaporation heat (skin, lung)
Gaseous exchange- whole animal-long term-respiration chamber, lung gaseous exchange-short term, Uses mask, hood, or tracheal cannula
Carbon-Nitrogen balance- conjunction w/ respiratory exchange studies, body retention of fat & protein, Body gain of C & N = C & N intake – C & N output
Explain in details all the important factors that affect requirement of net energy for lactation (NEL)
Net Energy Lactation (NEl) is the feed energy available for maintenance and milk production after digestive and metabolic losses.
- cow eats more feed= passes through her digestive tract more quickly.
- feed a cow at three times maintenance = lower than they would be for a cow that was just maintaining herself
- Energy is used with a different efficiency by the heifer for maintenance than for gain.
- ADF content of feeds and the NEl, as ADF increases, NEl decreases.
Efficiency of ME utilization is related to
Efficiency of ME utilization is higher for maintenance than for production and the NE yield of a feed varies, therefore, with ME intake.
In NE system, net energy for growth is determined based on?
Net energy for maintenance (NEm) and gain (NEg) are used to formulate diets for growing and finishing. These energy values are more useful than TDN, because they allow more accurate prediction of the amount of energy used for maintenance and gain purposes
Why would heat increment be different
- Different amount of heat from food ingestion
- Specific dynamic effect: Increase in HP associated with the combustion of a meal
1) Eating, 2) gut activities, 3) absorption, 4) cellular activities
What does heat production include
heat required to increase the temperature of 1 gram H2O by 1 degree centigrade (14.5 to 15.5) when the specific heat of H2O is 4.184 J/g.
ME minus heat production Heat of nutrient metabolism (basal metabolism) Heat of activity Heat of thermal regulation Heat increment in a thermo-neutral environment, HI includes: - heat of digestion & absorption - heat of fermentation - heat of products formation - heat of waste formation
Heat increment will increase with
Increase in HP associated with the combustion of a meal
1) Eating, 2) gut activities, 3) absorption, 4) cellular activities
Briefly explain factors that affect milk energy
- Milk composition and yields can be affected by genetics and environment, level of milk production, stage of lactation, disease (mastitis), season and age of cow.
- Fat concentration is sensitive to dietary changes and can vary over a range.
- Dietary manipulation results in milk protein concentration changing.
- The concentrations of lactose and minerals, the other solids constituents of milk, do not respond predictably to adjustments in diet.
- Feeding strategies that optimize rumen function also maximize milk production and milk component percentages and yield.
What are some Laboratory methods to measure vitamins
Spectrophometery
Atomic absorption
High pressure (performance) liquid chromatography
Gas chromatography
What are some biological methods to measure vit
Feeding studies
Purified rations
Slaughter studies
What are the fat soluble vitamins and sources
A- Green Leafy Forages
D- Fish Oils, Sun-Cured Forages
E- Seed Germ, Germ Oils
K- Green Forage, Sun-Cured Hay
What are some water soluble vitamins and sources
Riboflavin- Milk Products
Biotin- Egg Yolk
B12- Animal Protein, Fermentation Products
C- Citrus, Green, Leafy Plants
List some characteristics of fat soluble vitamins
- Contain C, H, O
- Can be present as a Pro-vitamin
- Primarily stored in fat tissue and liver
List some characteristics of water soluble vitamins
- Contain C, H, O and N, or S, or Co
- No Provitamin forms known
- No storage in body except Vit. B12
What is the functions of Vit. A
- Vision: Maintains normal vision in dim light formation of Rhodopsin
- Epithelium (skin integrity)
- Reproduction
- Skeletal growth
- Immune system
Name some deficiency symptoms in Vit. A
- Degeneration of mucosa of respiratory tract, mouth, salivary glands, intestinal tract, and kidneys
- Night blindness (decreased formation of Rhodopsin)
- Later stages permanent eye damage
- Dry skin
- Immune dysfunction
Function of Calciferol (Vitamin D)
- Aids in absorption and utilization of calcium and phosphorous
- Promotes bone and teeth growth
- bone mineralization
- functions as a hormone
Deficiency symptoms of Vit. D
Rickets
Osteomalcia
Function Vit. E
- Antioxidant - 1. prevents rancidification of fats in plants 2. Prevents body cells from oxidative damage.
- Integrity of red blood cells
- Heart and skeletal muscle respiration
- spares Selenium
- Reproduction
What does Vit. E interact with
- Selenium
- Vitamin C: Regenerates (reduces) vitamin E
- Beta Carotene
- Vit. K
Deficiency of Vit. E
-Muscular dystrophy
-White Muscle disease
Weakening of leg muscles-crossing of hind legs
Unable to stand
Heart may fail
