Exam 3: Lecture 19 - Dairy nutrition 3 Flashcards
are what the limiting AAs in most feeds for dairy cows
lysine and methionine
how can we provide extra lysine and methionine
soybean meal, dried brewers grain, blood or fish meal
T/F: fish and blood meal are palatable at high inclusion rates
FALSE! Not palatable
T/F: fish meal can reduce milk fat at high inclusion rates
true!
high ___ in rations can interfere with fiber digestion
high fat
molasses will be _______ fermented in the rumen
rapidly
what % of protein are most dairy rations
16-18% high quality protein
T/F: protein % should be towards the higher end in early lactation
true!
what are the consequences of overfeeding protein
infertility and lameness
how can overfeeding protein lead to infertility
excess ammonia/urea can delay maturation of oocyte or any developing embryo
how can overfeeding protein lead to lameness
excess protein can lead to fermentation products via bacteria that impact foot health
why is the balance between RDP/NPN and energy levels in the rumen important
microbes need energy from diet to use nitrogen from the diet to avoid ammonia acculumation
how do we get excess ammonia production
excess RDP, soluble protein, or NPN
what ingredient may be used to supplement lysine and methionine but is not very palatable?
A. soybean meal
B. corn gluten meal
C. fish meal
D. meat meal
C. fish meal
what are the major macro-minerals required in the diet
Ca, P, Mg, K, Cl, S
what macromineral is high in forage
potassium
what are the ranges we should supplement Ca (above the NRC requirements)
range from 0.62-0.67% in diet for 68-kg cow
if we add fats in the ration, what macrominerals should we increase
Ca and Mg by 20-25%
T/F: Ca:P ratios are not as important as meeting requirements of Ca and P
true!
__1___ deficiency is more common than _____2____ deficiency (macrominerals)
- P
- Ca
T/F: P deficient soils more common and P levels in plants drop faster than Ca as plants mature
true!
how much phosphorus should be included in dairy rations
about 0.35%
how many lbs of water/lbs DMI do dairy cows need
2-4 lbs water/lbs DMI
what do we increase the water intake to for milk
additional 3-5 lbs water/lb
what are the factors affecting water intake
bw, milk yield, DM consumption, temp, humidity, water temp, quality and availability of water, moisture in feed
what water temp do most cows prefer
63-82 degrees
what are the dimensions of water troughs
2 inches/cow, 3 inches deep, height of 24-32 inches
1 trough/watering device per how many cows
15-20 cows
how do we assess water quality
odor, taste, pH, dissolved solids, hardness, toxic compounds, nitrates, sulfates, iron, bacteria, algae
what happens with blue-green algae poisoning
ataxia, bloody diarrhea, convulsions, sudden death
what mineral is affected by the level K in soil and lack can cause grass tetany?
A. calcium
B. magnesium
C. phosphorus
D. sodium
B. magnesiusm
why do we have to maintain DMI in the close up dry cows
they are close to calving so bw drops so need to maintain adequate energy reserves for 6-8 weeks after calving
what is the BCS we want to maintain in dry cows
BCS of 3-4
when do we typically increase energy before calving
3 weeks prior to calving
what are the 2 approaches for feeding dry cows
- adapt rumen to grain diet
- level/consistent NDF feeding
how do we adapt rumen to grain diet
- adapt rumen prior to calving
- grain is ged to close-up cows
- since there is a fall in DMI before calving, this increased energy density makes up for the drop in intake
how do we do level/consistent NDF feeding
- need to maintain rumens ability to digest fiber
- feed very low energy, high fiber ration through calving and then add grain
- efficient fiber utilization buffers rumen pH and avoids acidosis when grain is added to the lactating diet
