Feedstuffs & Nutritional Physio

Question 1

Describe iodine.

Answer 1

-essential mineral for function of thyroid hormones
-deficiency = goiter in newborn calves
>rare in cow herds
-supplemented as EDDI w max legal @50mg/hd/d

Question 2

Describe iron.

Answer 2

-required for formation of hemoglobin
-deficiency = anemia, depressed immunity, decreased weight gain
>rare in grazing cattle
-iron oxide included in mineral mixtures
>unavail to animal & colors the mineral dark red
-iron sulfate = avail to animal & used if iron supplement needed

Question 3

Describe manganese.

Answer 3

-required for normal repro, fetal, udder development
-deficiency = rare in grazing cattle
>corn based diets low in manganese
—supplement needed
—roundup ready crops dont take up
-manganese oxide
>used in mineral mixes

Question 4

Describe selenium.

Answer 4

-destruction of peroxides = protect tissue against oxidative damage
-deficiency = calves weak at birth
>white muscle disease “zenkirs” necrosis
>increased rates of retained placentas & poor repro performance in cows
-toxic (should be used in premixed form only)
*cant exceed 0.3ppm of dry matter in total diet

Question 5

Describe bioavailability coefficients of minerals.

Answer 5

Bioavailability coefficients of minerals from diff sources used to form diets that meet need of cow w/o excessive excretion of minerals in manure = neg impact on environment.

Question 6

Describe micro nutrients in monogastrics VS ruminants.

Answer 6

Question 7

Describe fat soluble vitamins in monogastrics VS ruminants.

Answer 7

DAIRY CATTLE:
-depends on amount naturally in diet
-high grain diet = increase amount of ruminants vit destruction & increase requirements
-availability & utilization rate
>availability of A,D,E, beta carotene adversely influenced by poor fat digestion
-fresh forage = vit A (precursor beta carotene) & vit E

Question 8

Describe vitamin A.

Answer 8

-imp for:
>normal bone development
>maintenance of epithelial cells
>night vision
-made via conversion from beta carotene
-found in green feed & stored in liver
-deficiency = prolonged period of drought, grazing dry, mature pasture grazing (corn stubble)
>night blindness, eye discharge, ill thrift

Question 9

Describe vitamin D.

Answer 9

-in sun cured hay & made in skin of animals thru irradiation
-stored in liver & regulates Ca:P balance
-deficiency = rare
>ill thrift, anorexia, hunched back, rickets (swollen joints, bowlers, knock knees)

Question 10

Describe vitamin E.

Answer 10

-imp for:
>unsaturated FA metabolism
>maintenance of cell membrane
-deficiency = young stock raised w/o green feed for months
>lameness, muscle weakness, ill thrift, white muscle disease

Question 11

Describe water soluble vitamins in monogastrics VS ruminants.

Answer 11

Question 12

Describe the clinal response to Niacin in ruminants.

Answer 12

Niacin (B3)
-prophylactic & therapeutic effect on ketosis & fatty liver syndrome
-niacin supplement during periparturient period = reduce blood ketone & plasma nonesterified FA
-supplement @12g/d = increase milk production by 1lb/d
*pos investment more likely when limited to early lactation cows

Question 13

Describe the clinal response to Biotin in ruminants.

Answer 13

Biotin (B7)
-requirement not est for dairy cows
-supplement (20mg/h/d) on hoof horn lesions & lameness = reduced prevalence of specific lesions or clinical lameness
-milk yield response to supplement biotin = less consistent than hoof responses (studies show increased production)
*mech unknown

Question 14

Describe choline.

Answer 14

-not a vit
-required in gram quantities
-supplementation during transition period (50g/d) up to 60d post partake = reduce liver fat & increase milk production 5lb/d
-syn from methionine
>dairy diets w marginal methionine more likely to have pos response
>choline must be rumen protected

Question 15

Describe vitamin C.

Answer 15

-most imp water soluble antioxidant in mammals
>most forms extensively degraded in rumen
-conc of ascorbic acid high in neutrophils & increases 30 fold when neutrophil is stim by bacteria
>mastitis = decreased vit C
>lower levels = cows get infected or infection depletion

Question 16

Describe macro nutrients of fiber in ruminants VS monogastric.

Answer 16

Question 17

Describe plant structure.

Answer 17

-young plants = single outer layer (primary cell wall)
-maturation = second layer inside of cell
-secondary cell wall = structural strength of plant
>reduce palatability & digestibility
>advancing maturity = more lignin
-monogastrics = limited ability to digest cell wall compounds
-forage eaters depend on microbial pop in GIT to ferment cell wall constitutents into usable nutrients

Question 18

Describe forages VS grazing forages.

Answer 18

1. Forages
   -grazing, dried, green chop, silage, acid treated
2. Grazing forages
   -ryegrass, oat, wheat, tritacale, barley
   -perennials: tall fescue, Timothy, brome grass, orchard grass, blue grass, Bermuda grass

Question 19

Describe the diff types of hay.

Answer 19

MUST BE PRESERVED AT DM ABOVE 85%
1. Grass hay = Timothy, orchard, brome, Bermuda, Bahia
2. Cereal grain hay = oat, wheat, corn
3. Hay = legumes, grass, cereal grain

Question 20

Describe legumes.

Answer 20

-alfalfa
>high nutritional value if processes at early bud stage

Question 21

Describe the cost of hay feeding.

Answer 21

-0.02$ & 0.07% per lb of DM
-doubles cost for same amount of nutrients from pasture
>lg investment in equipment
>labor to make & feed
>50% wasted by poor storage or improper feeding

Question 22

Describe corn silage.

Answer 22

-early planting of corn for silage = increase gain content & lower stalk height
-corn used for silage planted at rate of 2k to 3k more stalks per acre than corn for grain
-100bushel corn crop harvested as silage removes more than 2x N, 2x P, & 10x K as when crop is harvested for grain
-corn cut into particles 1/2 to 3/4 in in length = packs firm in silo & more palatable
-finer cut silage inc DM
>less palatable = lower butterfat tests when fed as primary source of roughage for dairy cattle
-corn plant cut & breathing makes CO2 heats using trapped air & anaerobic
-80-100F = bacteria use starches & sugars from plant
-acetic & lactic acids made by bacteria cont until overwhelm bacteria pH of 4.2 ideal & occur in 3wks
-excess air escape of CO2 = allow respiration to cont -> cells use too much sugar & carb wasting nutrients needed by bacteria for preservation
-too wet = seepage
-too dry = poor packing & moldy

Question 23

Describe silo gases.

Answer 23

-lethal gases occur any time during silo filling
-greatest danger 12-72h after filling but occur up to 10d
-NO2 = reddish brown
-N2O4 = yellow
-NO = colorless
pit silos are safer

Question 24

Describe silage quality.

Answer 24

-determined by energy content & intake potential + content of protein & minerals
-energy content determined by amount/digestibility of fiber
-grain content affects energy values
>corn silage <30% grain higher in energy than that w more than 50% grain due to starch digestibility
>90d fermentation
-NDF conc 36-50%
>low corn silage NDF is good
-ADF conc 18-26%
corn silage with low ADF = higher energy content (:

Question 25

Describe silage additives.

Answer 25

-quality silage made w/o addition of additives or preservatives
-no evidence for additives to inc feeding value
>molasses/grain added to corn forage at time of ensiling
>enriches silage as feed, some fermentation loss