Exam 3 Flashcards
AA and nitrogen metabolism in non-ruminants
Stomach- protein goes to peptides
SI- degrades to AA
Liver- AA goes to body
AA and nitrogen metabolism in ruminants
Rumen- AA +energy= microbial protein, AA to ammonia goes to liver to be nitrogen
Liver- AA to Nitrogen to body
Why do we need continuous replacements of proteins?
Metabolic turnover
How are proteins absorbed and metabolized?
Free amino acids (some small peptides too)
Major metabolic fates of absorbed AA
Protein synthesis, catabolism (deamination, oxidation)
AA catabolism
Liver- AA to keto acids, AA to NH3 + CO2= urea
Kidney urea to urine
Where does AA catabolism take place?
All tissues but mainly liver
Ketogenic and glucogenic AA can be metabolized to yield ___
Energy-rich ketones or glucose
When is AA catabolism increased?
1) Gluconeogenesis from AA is increased (starving animal)
2) Dietary protein intake exceeds requirements
3) Composition of absorbed AA is unbalanced (1+ AA is limiting regardless of total protein intake)
What do optimal rates of tissue protein synthesis require?
1) Adequate total quantity of AA
2) Mixture of AA that matches the compositions of the proteins being synthesized
What is biological value?
Ability of a specific dietary protein to supply AA in the relative amounts required for protein synthesis to body tissues
What is biological value influenced by?
Essential AA composition
Biological value is not fixed but varies with what?
Varies with the varying needs of different species, and physiological and nutritional states
What AA is the most limiting?
Methionine
Limiting AA theory
Once the most limiting AA is met, the next limiting becomes halts the process, before that is met, and this continues until all AA are at their requirement
How does glucose get from the gut lumen to the bloodstream?
Active transport from gut lumen to epithelial cell, facilitated diffusion from epithelial cell to interstitial fluid, passive diffusion from interstitial fluid to capillary cell to bloodstream
What is the ultimate source of energy for most animals?
Glucose
What is the major source of energy in the diet?
Carbs
Carbs are a higher proportion relative to other sources in ___ diet compared to ___ diet
Herbivore, carnivore
What is the most important vehicle for post-absorptive carb metabolism?
Blood glucose
The __ provides an important source of glucose
Diet
Sources of glucose other than diet
Glycogenolysis in the liver, Gluconeogenesis in the liver and kidneys
In what form is glucose stored?
Glycogen
How is glycogen stored in animals?
Straight chain of alpha 1,4 linked glucoses, further chains branching off by alpha 1,6 bond (same as start in plants)
Where is glycogen stored?
Muscle (~2%), liver (8%)
How much weight is stored as carbs?
Less than 1%
Where does gluconeogenesis occur?
Mainly in liver, also in kidneys
What is the rate of gluconeogenesis in nonruminants?
Rate varies inversely with rate of glucose absorption, precursors are of endogenous origin
How do glucose absorption, glycogenolysis, and gluconeogenesis change as time after feeding increases?
Absorption- peaks at hour 6 and gradually decreases
Glycogenolysis- peaks at hour 12 and decreases, leveling out
Gluconeogenesis- Dips at hour 6 and gradually increases before leveling at hour 18
What happens when dry matter intake does not meet the energy requirement?
Plasma NEFA increases
What are the two metabolic fates of glucose?
Catabolism and anabolism
Glucose fates in catabolism
Glycolysis–> lactate
Oxidation–> CO2+H2O
Glucose fates in anabolism
Glycogen synthesis
Lipid synthesis
What happens in a glucose deficiency?
Glycogenolysis to release glucose
What can occur in periods of glucose deficiency?
Ketosis
What is fatty liver?
Accumulation of triacylglycerol (fat) in liver
How do lipolysis and ketogenesis occur?
Adipose tissue–> NEFA in blood –> NEFA in liver–> TAG, CO2, Ketones. Ketones in liver–> ketones in blood
What are the three ketone bodies?
3-hydroxybutyrate, acetoacetate, acetone
What are the three major controls of feed intake control?
1) Physical capacity of digestive tract and its rate of emptying (Ballast theory)
2) Availability of feed
3) When neither of the above apply, metabolic control
What is Ballast Theory?
The physical capacity of the digestive tract is physically limited by volume
What are factors that influence the capacity of the digestive tract?
Volume of abdominal organs (fat, pregnant uterus), voume of GI tract (long period of under-nutrition)
How is distention of the GI tract relieved?
1) Extent of digestion (greater extent, the more the tract empties)
2) Rate of digestion of digestible material (faster the rate the quicker the tract empties)
3) Rate of passage of indigestible DM (faster the rate, sooner the tract empties)
What is the trend of litter size compared to daily DM intake?
As litter size increases, daily DM intake decreases
Feed intake is higher at a given digestibility/ME for animals with ___
High feed requirement, showing compensatory growth, poor body condition
Feed intake is lower at a given digestibility/ME for animals with ___
Low feed requirement, no growth, good body condition, diseases or parasitism
Ballast theory holds best for ___
Ruminants, low quality feeds
Eventually ___ declines as ___ increases
DMI, disgestibility
Rumen of animals on ___ quality feed is ___ full
high, never
What increases as pasture availability decreases?
Bite-size, biting rate, grazing time
What factors affect grazing time?
Bite size, biting rate, genetic potential, physiological state
How long do animals graze per day?
Max 10-11 hours min 4-5 hours
What factors affect grazing intake?
Height, density, mass, digestibility/leaf strength, composition, stocking rate, availability
How does CNS contribute to metabolic control?
1) Senses nutrient intake and body reserves
2) Integrates information
3) Regulates intake (dominant signal wins)
Orexigenic
Stimulates feed intake
Anorexigenic
Suppress/inhibit feed intake
What do signaling pathways do in metabolic control?
Stimulate and inhibit feed intake
Tissues that communicate to CNS
Gastric stomach, SI, LI, Pancreas, Liver, Adipose tissue
Where is cholecystokinin (CCK) produced?
Duodenal and jejunal cells
What is CCK release stimulated by?
Release stimulated by transfer of digesta from stomach to duodenum (AA, HCl, fatty acids
What does CCK do?
1) Causes gallbladder to empty and pancreatic enzymes to be secreted
2) Inhibits gastric emptying
3) Increases intestinal motility
4) Anorexigenic
Where is ghrelin produced and released?
Primarily by gastric oxyntic cells (abomasal) and minimal released by duodenum, ileum, cecum, and colon
Ghrelin characteristics
Orexigenic, not distension-mediated (is endocrine)
Where is insulin secreted?
Secreted form beta cells in the islets of Langerhans in pancreas
What is the role of insulin?
Anorexigenic, regulate blood glucose levels by increasing tissue (e.g. liver) glucose uptake and glycogen storage, promotes AA uptake
Where is glucagon secreted?
Glucagon secreted by alpha cells of the pancreas islets?
What is the role of glucagon?
anorexigenic, increase blood glucose by increasing glycogenolysis or gluconeogenesis
Where is leptin secreted?
Secreted from the white adipose tissue
What is the role of leptin?
Suppress feed intake (anorexigenic), product of the ob gene
When would leptin levels decrease?
When white adipose reserves are being depleted and appetite increases
What happens when the ob gene (that codes for leptin) is knocked out?
More adipose tissue because the fat is no longer signaling in an endocrine way to stop ending
Which satiety signal is secreted from adipose tissue?
Leptin
What are net nutrient requirements?
Net requirements of nutrients for conceptus growth, nutrient deposition in tissues of gravid uterus
What is the gravid uterus?
Encompassing all female reproductive organs
What does metabolic and nutritional impact of pregnancy on the dam depend on?
Ratio of fetal weight and maternal weight, gestation length
The ___ the fetus is relative to dam size, the ___ more energy it takes to grow offspring
Bigger, more (guinea pig vs human)
What is the gestation length of a sow?
3 months 3 weeks 3 days
Does a longer pregnancy need more energy?
No definitive answer but also depends on development when leaves the womb
When do energy requirements change during pregnancy?
Third trimester. First two are fetal development and third is fetal growth
Serious under and over-feeding can cause what during early pregnancy?
Increased embryo mortality
What is the recommendation to feed during pregnancy?
Feed at or a little above maintenance for about a month after breeding since well-conditioned animals can afford to lose weight through mid-pregnancy if they are well fed during late pregnancy
Why should overfeeding be avoided in pregnant animals?
Early and mid pregnant animals synthesize and deposit fat very easily, overeating will store as fat
What does the pregnant body do to prepare for later pregnancy?
Gets very good at storing things and nutrient absorption because fill limitation in GI tract decreases. It cannot fit in the space so high nutrient small meals
How do fat synthesis and mobilization change during pregnancy?
synthesis- increases and peaks at like 10 days, decreases gradually then rapidly
Mobilization- decreases and plateaus until day 50, gradually increases
Why do requirements accelerate after mid pregnancy?
Everything is in its place and just needs to get bigger, higher density in nutrients and higher digestibility due to fill limitation
T/F Placental and uterine weight increase during the last trimester
True
Most of extra energy required by the dam to support pregnancy is converted to ___
Heat (why women are always hot)
What are the sources of the heat increment of pregnancy?
Fetal metabolism, uterine and placental metabolism, Increased metabolism in maternal tissues
What are some specific nutrient requirements in late pregnancy?
Fetal metabolism and growth, placental transport, metabolic impact on the dam, Ca and P requirement increase from maintenance
What is different in requirements for egg layers?
Calcium has a drastic increase due to calcium carbonate shell and maybe choline for maximum egg yield
What is the Ca:P ratio for egg layers?
7:1 or something like that
How does DMI trend before and after calving?
DMI decreases leading up to calving, then increases rapidly after calving
How does NEFA trend before and after calving?
Increases and spikes before calving, then decrease after calving
Dramatic increase in nutrient requirements during early lactation is met by what?
1) Diet which is often not adequate enough to meet requirements
2) Rapid mobilization of endogenous reserves (fat, Ca, protein)
When are cows in negative energy balance?
Shortly after calving when there are high NEFAs and losing weight
When does normal diet alone become sufficient to meet requirements of dam?
As lactation progresses
What is the nutrient requirement for lactation?
Higher total energy, protein, mineral, vitamin (almost everything higher)
How is lactose synthesized?
2 glucose goes to 1 glucose and 1 galactose which combines to be 1 lactose (disaccharide)
Milk fat is ___% triacyglycerol
> 98%
Milk protein composition
80% Caseins 20% Whey (B-lactoglobulin, a-lactalbumin, other)
Nutrient requirements associated with ___ are much higher than ___, and even ___
Lactation, maintenance, pregnancy
Animal growth is the progressive net ___ of nutrients and their metabolites
accretion
What is perinatal?
Around the time of birth (-3 mo to +1 mo)
What is neonatal?
First month of birth
Where do the nutrients for growth come from?
Pre-weaning period: milk
Weaning period: Milk and feed
Post-weaning period: feed
What does colostrum contain?
Immunoglobulins to provide passive immunity to newborn ruminants, vitamins and minerals to aid in development and microbial metabolism (rumen and colon)
When does a calf move to a non-milk diet?
When the dam milk volume declines, food volume/amount of nutrient required increases, microbe population establishes
What can we use to determine an animal’s specific needs?
US guidelines set by the National Research Council (NRC) outline requirements for species, maintenance, and other physiological states
What does the NRC guidelines include?
Tables of nutrient requirements, information regarding specific considerations like susceptibilities and toxicities, and typical diet ingredients
No animal has a nutrient requirement for ___
Carbs
____ must be included in the diet of ruminant in order to maintain rumen health
Beta-linked carbs
What are forages?
Leaves and stems of grasses, legumes, and brassicas including fresh, hay, silage, and crop residue
What are characteristics of forages?
Typically high in fiber (>18% DM) so high in beta-linked carbs
What is the rule of thumb for forages?
If forage is >32% NDF or >22% ADF then it is relatively low in energy (lots of hemicelluloses cellulose, and lignin)
How is a rumen separated?
Gases on top (CO2, methane)
Fiber mat (light fibrous material, grass before it gets waterlogged)
Liquid on bottom (more dense material with microbes)
What the pH and required feed for acidosis?
Above 5.5 is ideal- long grass/forage
Below 5.5 is acidosis- more dense feed
___ fiber, ___ the rumen PH
More, higher (fiber slows down digestion opposite of humans)
What are characteristics of concentrates?
Includes most grains and high-quality byproducts, concentrated in a nutrient (normally energy or protein), low in NDF and ADF,
What is the rule of thumb for concentrates?
<32% NDF or <22% ADF and high in energy
High grain diet almost always causes ___ and can cause ___
Metabolic acidosis, laminitis
General features of lactation ketosis
5-10% of cows <2 weeks after calving
May be secondary to decreased DMI caused by infectious disease or other metabolic disturbance
What are symptoms of lactation ketosis?
Hypoglycemia, hyperketonemia, metabolic acidosis
Decreased DMI, milk yield, body condition
Increased excitability or apathy
Recumbency, death if not treated
Prevention of lactation ketosis
Maintain 3 BCS during late pregnancy
Feed adequate energy during late pregnancy
Maximize DMI during late preg and after calving
Alternative strategy of prepartum caloric restriction
Treatment of lactation ketosis
Orally dose with propylene glycol
Inject glucose IV
Inject dexamethasone IM
General Features of Milk Fever
8-9% soon after calving mostly in Jerseys, old ladies
Associated with other production diseases
Severe hypocalcemia
What is milk fever?
Onset of lactation causes massive drain on extracellular Ca pool that cant be totally met by changes in absorption
Ca goes to milk so not Ca left in body (Ca input cannot handle or sustain Ca export)
Symptoms of milk fever
Muscular spasms, recumbency, paralysis, unconsciousness, death if not treated
Why don’t heifers need SQ Ca?
They’re still growing so their bones can make enough calcium to counteract the loss
Prevention of milk fever
So that cows get used to mobilizing Ca from bone- feed cows <100g Ca per day with Ca:P <2.5:1 2 weeks before calving, increase mineral acidity of close-up ration (reduce Ca, Na, K, increase Cl, S)
Treatment of milk fever
SQ or IV Ca
Carb Requirements for dairy cows
Non-fiber carbs need to be <44% DM or risk of acidosis
NDF- 29% of total diet DM (25-33)
ADF- 19% total diet DM (17-21)
Total crude protein requirement for dairy cows
16-18% DM for early lactation
16% DM for mid lactation
14% DM for late lactation
12% DM for dry cows
Fat requirements for dairy cows
<6% of DM (above that will show negative effects)
What increases as beef cattle age increases?
Mad cow and other diseases
Meat gets tougher as animal gets older
What is the life of a beef cow?
Gets pregnant every year and nurses calf (good moms)
What is the life of a beef boy?
Nurses and then weans
Goes to backgrounding to gain weight
Goes to finishing on high grain diet
Becomes burgers
Grass finishing
Stay on grass, 6-10 months, longer for animals to get to market cause high in fiber low in energy, better welfare, not much differs nutritionally from grain
Grain finishing
High energy high carb concentrate grain diet, 4-6 months, energy content higher so they gain weight faster
Bloat
Gas buildup in the rumen due to froth from high soluble protein diet like fresh alfalfa
Treated by gas relief puncture in rumen
More common in grazing animals
Acidosis
Due to highly fermentable diet
More common on finishing diets for long periods of time
Can develop gut lesions, bacteria, rumen wall and liver abscesses
What is grass tetany?
Low magnesium
What is white muscle disease?
Low selenium
What is water belly?
Kidney/bladder stones due to excess phosphorus
What is hardware disease?
When a cow swallows metal so most milking cows have a magnet in the bottom of their rumen
In beef cows, ketosis occurs more frequently as ___
Pregnancy toxemia
What is pregnancy toxemia?
High fetal demand (likely due to twins) so GI tract is small because there’s no room during late pregnancy
What is the maintenance energy for a beef animal?
4 (200kg) to 7.5 (450kg) (in Mcal/day)
What is the growth energy for a beef animal?
1 (low BW and ADG) to 13 (High BW and ADG) (in Mcal/day)
What is the Crude protein requirement for a beef animal?
6 (High BW and low ADG) to 22 (low BW and high ADG) % of DM
What is the maintenance energy for sheep?
1.48 (small mature) to 10.11 (large early lactation)
What is the crude protein requirement for a sheep?
6% (non-lactating) to 16% (growing or early lactation) of DM
What are the essential fatty acid requirements for a sheep?
0.043 g/kgBW^0.75 to 0.055 g/kgBW^0.75
Symptoms of Acute copper toxicity in sheep
Discoloration
Jaundicing of gums, third eyelid, skin
Kidneys, liver are gunmetal (latter can be bronze)
Really dark urine
Prevention of copper toxicity
Avoid copper-rich feed (essential so only in low levels)
Use grain byproducts and concentrate mixtures carefully
Increase Molybdenum or Sulfur in diet
Test Cu, Mb, S in feeds
Watch out for other physical copper sources
What is the maximum tolerable level of copper in a sheep’s diet?
15mg/kg
What AA should be paid attention to in wool sheep?
Very high composition of cysteine and arginine
General features of pregnancy toxemia in sheep
Higher incidence than beef cows, occurs late pregnancy when carrying twins or triplets, more common in very thin or obese dams, may be triggered my stress
Symptoms of pregnancy toxemia in sheep
Hypoglycemia, hyperketonemia, metabolic acidosis (all in last 2-4 weeks of pregnancy), progressive depression of consciousness, decreased awareness, neuromuscular disturbances, recumbency, death
Treatment of pregnancy toxemia in sheep
IV glucose
What diseases are goats susceptible to?
All the same diseases covered for other ruminants
Copper requirement for goats
Lactating- 15 mg/kg
Mature- 20 mg/kg
Growing- 25 mg/kg
no max
Max tolerable level of copper requirements for cattle
40 mg/kg
Llamas and alpacas have higher susceptibility to what?
Vitamin D associated rickets
Fatty liver (hepatic lipidosis)
Maybe zinc deficiency
What are the four feed considerations for fish?
Type of feed
Size of pellet vs size of fish
Sinking vs floating feed
Even distribution of feed
What fish feed floats?
High carb
What are the three types of fish feed?
Live feed, moist feed, dry feed
Pros and Cons of Live fish feed
Pro- attractive
Con- Expensive, handling, storage, nutritionally balanced?
Pros and Cons of moist fish feed
Pro- palatable, economical
Con- Pollution (dispersion in water)
Pros and Cons of dry fish feed
Pro- supply, storage, handling
Con- Less attractive
Animal considerations for fish
Poikilothermic (body temp)
Plastic growth
Crude protein requirement for fish
28-38%
Same 10 essential AA (PHILL, MT, VAT)
Commercial feeds: 22-68% DM
Fat requirement for fish
0.5-2%
EE of commercial feeds: 22-68% DM
Daily energy requirement for fish
3000-3600 DE/kg diet (as fed)
Carb requirement for fish
N/A included in diet to increase energy density and other carb-derived metabolites
Commercial feeds: 8-50% DM
Vitamin requirements for fish
Vit c, and basically everything else
Inclusion of supplements to increase pigmentation
T/F gut fill may limit intake in layer chickens
True
What is the size of an egg dependent on?
BW of bird
Want eggs to be max 61g
Egg shell is (by weight):
94% Calcium carbonate
1% magnesium carbonate
1% calcium phosphate
4% organic matter
What are nutritional issues for layer hens?
Rickets in growing birds
Cage layer fatigue (Ca def or mineral imbalance?
Fatty liver syndrome
Vitamin deficiencies
Eggshell is (by weight):
94% Calcium carbonate
1% magnesium carbonate
1% calcium phosphate
4% organic matter
During laying how does the Ca:P ratio change?
2:1 -8-12:1
How much can broiler chicken gain a day?
60 g/day
Male broiler chickens respond to higher ___ and has a higher ___ requirement
Crude protein, P
Nutritional issues with broiler chickens
Ascites (water belly)(Right ventricle failure due to rapid muscle growth and slower lung capacity gain)
Monitoring Ca, P, D for bone development
Monitoring Lys for muscle deposition
Chicken feed is typically high in what and is what base?
High corn and a soybean based diet
What should you watch for in chicken feed?
Mycotoxins especially in corn
What is canola meal?
glycosinolates and erucic acid can give fish taint to brown eggs
Who should not be fed cottonseed meal and why?
Laying hens because gossypol content creates discoloration of yolk
Additives to chicken feed
Anticoccidial (mostly Na/K)
Growth promotant
Antibiotics/fungals/oxidants
Pellet binders (sticky lignin, clay)
