Dairy 2

Question 1

what is the dry period in cattle? give length and what happens to mammary gland

Answer 1

period between end of one lactation and beginning of next [this will be before parturition]. mammary gland is involuting during first 5 weeks. total length is 50-60 days

Question 2

what is the 2 group nutritional scheme for dry period

Answer 2

in the 2 group scheme, diet 1 has lower Mcal/kg and is fed until 21 days before parturition. diet 2, the last 21 days before birth, has higher Cal/kg

Question 3

give at least 3 reasons why transition period in dairy cows is a critical time of life

Answer 3

many physiological and metabolic changes (from pregnant nonlactating to non pregnant lactating), most health disorders occur during this time, most infectious diseases occur during this time (eg. milk fever, ketosis, immunosuppression mastitis), important for health and production of the animals

Question 4

definition of transition period in dairy cows

Answer 4

period between 3 weeks before and 3 weeks after parturition

Question 5

in the dry period, what is happening to the rumen

Answer 5

adaptation of rumen microbiota to digest higher starch diet, adaptation of epithelium and papillae to absorb large amount FVAs produced by fermentation, size of luminal papillae are decreasing and then 2 weeks pre-parturition begin increasing

Question 6

during the transition period nutrient requirements are __ and DMI is ___ (at least until birth)

Answer 6

increasing, decreasing (after birth, DMI increases)

Question 7

what is linked with greater incidences of periparturient health problems

Answer 7

excessive lipid mobilization from adipose tissue

Question 8

DMI increases or decreases as calving approaches during transition period of dairy cows

Answer 8

decreases

Question 9

how does body condition target score change from calving day to dry period

Answer 9

calving day target BCS is 3.25-3.75, this drops to a low of 2.25-2.75 at 75 days post calving (while they are in negative energy balance), then increases back to 3.25-3.75 by beginning of dry period.

Question 10

with short dry periods (under 30 days) or no dry period, cows may have ____

Answer 10

lower chance of somatic cell count reduction due to self-cure or cure achieved with dry cow antibiotics

Question 11

what are 3 benefits of shortened dry periods (28-40 days)

Answer 11

allow 1-group nutritional scheme, can be used for multiparous cows to extend lactation period, and simplifies nutritional management of farm

Question 12

describe high-fibre controlled energy dry cow feeding “Goldilocks diet”

Answer 12

provides just enough energy to cow, lots of chopped straw, includes ingredients of lactation diet, forage NDF is 40-50% of DM, fed as TMR, may need to add water

Question 13

objectives of well balanced early lactation diets

Answer 13

maximize DMI, supply minimum requirement of fibre and protein, maximize diet energy availability, balance protein and carbohydrate fractions, meet all nutritional needs, prevent loss BCS and maximize milk production

Question 14

heifers have a higher %DMI (by BW) compared to cows in the 3 weeks before calving, true or false

Answer 14

heifers have lower DMI compared to cows. (both cows and heifers are decreasing their DMI intake in the 3 weeks before calving)

Question 15

in an obese cow, there will be a larger and more problematic reduction in DMI in the 3 weeks approaching calving, true or false

Answer 15

true

Question 16

why do we even bother maintaining rumen fill during dry period of cow? give at least 2 reasons

Answer 16

decreases assisted calving, milk fever, retained placenta, displaced abomasum, and ketosis

Question 17

give 5 parameters that should be monitored in early lactation

Answer 17

intake, poops (consistency, presence of grind. and finer particles), milk fat concentration, milk solids (higher protein than fat is not good), BCS

Question 18

as milk production increases (kg/d), BW loss ____

Answer 18

also increases (higher negative energy balance)

Question 19

Bertha the cow has went from BCS 3.75 to 2.75 from day 0 to 30 postpartum. should we be concerned she has lost this much body condition?

Answer 19

as long as we limit the BCS change to more than -1.25, and her lowest BCS is above 2.25, it is ok (negative energy balance is normal during this time)

Question 20

at 4 days postpartum (very early lactation period), cows are consuming _____ net energy and metabolizable protein than is required to maintain a) neutral energy balance? b) demands of mammary use

Answer 20

a) less net energy and metabolizable protein that is required to maintain neutral energy balance (ie. they are in negative energy balance). b) enough for mammary use

Question 21

what is the length of the net energy balance in cow location period? when is it most severe? what do we need to pay careful attention to during this time?

Answer 21

45-50 days; most severe first 3 weeks postpartum; monitor BCS

Question 22

cows need nutrients for maintenance, lactation, growth, and gestation during their lactation period. the nutrient requirements of lactating cows vary according to what 6 factors

Answer 22

parity, cow size, body condition, milk production, physical activity/temperature, gestation/fetal growth

Question 23

how is water lost from Bessie the cow

Answer 23

milk production, urine excretion, fecal excretion, sweat, vapour loss from lungs

Question 24

what sources of water does Bessie the cow have

Answer 24

drinking/free water intake, ingestion in feed, water produced by body metabolism of nutrients

Question 25

did you know, cows drink several times a day, up to 150 L/day and 4-15 kg/minute. water intake is increased by what 5 factors?

Answer 25

milk production, diet DM, diet salt content, exposure to direct sunlight, high temperature (drink 29% more at 30C compared to 18C)

Question 26

water availability and quality are important for animal health and productivity. how much salt should be in good water

Answer 26

under 100 mg/L total soluble salts (TSS)

Question 27

deficiencies in trace elements and vitamins, especially Se and vitamin E, may be associated with what

Answer 27

increased reproductive disease

Question 28

rumen microbes make what vitamins

Answer 28

vitamin K and all B vitamins, as long as the rumens are healthy (if stressed may need added B3 (niacin) and thiamine (B1); minerals and vitamins are supplemented in feed as well)

Question 29

what is net energy for maintenance in a 650 kg cow

Answer 29

NE maintenance per day = 0.080 Mcal/kg x BW^0.75 = 0.080 Mcal/kg x 650^0.75 = 10.3 Mcal/d

Question 30

what is net energy for maintenance? what is NE for lactation in a 650 kg cow who produced 10 kg milk?

Answer 30

energy contained in milk produced. the true formula is NEL (Mcal/kg) = (0.0929 x fat%) +( 0.0547 x CP%) + (0.0395 x lactose%). the shortcut is 0.68 Mcal/kg milk, so about 6.8 Mcal/10 L. I don't know if we need to know the long formula. (also the cow weight doesn't matter, I was being tricky)

Question 31

what is the effect on NE lactation as: milk CP% increases? milk fat % increases? milk lactate % increases?

Answer 31

these all increase the net energy for lactation

Question 32

for every 10 degree C reduction in ambient temperature below 20 degrees C, what is the effect?

Answer 32

1.8% reduction in DM digestibility for lactating cows (increases DMI which increases rate of passage of feed through digestive tract)

Question 33

mild to severe heat stress have what affect on maintenance requirements?

Answer 33

increase (estimated by 7-25%, which is not great because DMI is reduces by heat stress. note heat stress is affected by ambient temperature, relative humidity, radiant energy, and wind speed)

Question 34

primary goal of any nutrition program is

Answer 34

formulate diets that meet nutrition requirements of animal

Question 35

what 2 things are needed as a major factor influencing nutrient utilization, to design an effective nutritional program for lactating dairy cows

Answer 35

DMI (the most important) and nutrient digestibility

Question 36

what is DMI driven by in lactating dairy cows? does DMI increase increase or decrease digestibility of nutrients?

Answer 36

milk production. DMI increase (eg. due to increased milk production)--> faster passage rate of ingest --> decrease digestibility of nutrients

Question 37

give the DMI (kg/d) in a cow with 4% fat corrected milk (FCM), 600 kg body weight (BW), at 4th week of lactation WOL).

Answer 37

DMI (kg/d) = [0.372 x FCM + 0.0968 x BW^0.75] x [1-e^(-0.192 x (WOL + 3.67)] = [0.372 x 0.04 + 0.0968 x 600^0.75] x [1-e^(-0.192 x (4 + 3.67)] = 9.06 kg/d. (note: there's no sample calculation so I don't know if this is right. also you are adjusting as needed in practice)

Question 38

give the super approximate DMI, BW, milk production, %CP, %NDF, %starch, and %fatty acids for cows in Michigan, Ohio, Georgia study

Answer 38

23 kg/d DMI, 669 kg BW, 38 kg/d milk, 17% CP, 31% NDF, 27% starch, 2.6% fatty acids (I really don't know what we're expected to memorize, sorry)

Question 39

as DMI increases, dry matter digestibility decreases according to the model formula DMD = 69 - 0.83 x DMI%BW.. the model works well for Ohio cows (midwestern USA) but not Georgia (southern USA). why?

Answer 39

the model works better for cooler areas. Georgia's a warm state

Question 40

***as forage fibre increases in the diet, what happens to DMI***

Answer 40

***reduces DMI*** (note if there is too little fibre, adding fibre will help DMI, ie. increasing 20-25%. but then decreasing when cow is fed feasible rations of 25%-45%)

Question 41

as NDF (as % of DM) increases in diet, what happens to DMI? what happens to fill limitation?

Answer 41

as NDF intake increases, max DMI increases, but fill limitation value decreases (say you fed 30% NDF to a cow, its fill limitation is at 4%, but it will only eat 2.75% DMI (for this particular cow). if you increase to 40% NDF, its fill limitation is now decreased to 3% but its DMI has increased to 3%)

Question 42

optimum NDF intake occurs at

Answer 42

point of maximum milk yield, usually about 1.25% BW per day for cows in mid to late lactation

Question 43

are cows eating more or less at second lactation, compared to first

Answer 43

more

Question 44

pectins, hemicellulose, lignins, and cellulose make up cell walls. which are part of NDF? which are part of ADF?

Answer 44

hemicellulose, legnini, and cellulose are part of NDF (non-digestible fibre) (lignin is a non-fibre carbohydrate). only lignins and cellulose are ADF (acid detergent fibre)

Question 45

what is formula for NFC (non fibre carbohydrate)?

Answer 45

NFC = 100% - CP% - NDF% - EE (ether extract) - ash

Question 46

the volatile fatty acids ____ and ___ are used to produce triglycerides, responsible for milk fat. ____ is used to produce glucose and lactose, responsible for milk yield

Answer 46

acetate and butyrate; propionate

Question 47

as the concentrates in diet increase and forages decrease, milk production _____

Answer 47

increases until 70:30 concentrate:forage ratio, at which point it plummets

Question 48

as the concentrates in diet increase and forages decrease, milk fat _____

Answer 48

remains steady until 70:30 concentrate:forage ratio, at which point it decreases

Question 49

as the concentrates in diet increase and forages decrease, what happens to total VFA production, propionic acid production, acetic acid production, and butyric acid production

Answer 49

total VFA production and propionic acid production increase until concentrates exceed 70% of diet, at which point they decrease. acetic acid produced decreases. butyric acid remains the same

Question 50

as milk fat production increases, luminal pH

Answer 50

increases (more alkaline)

Question 51

which ferment the fastest in the rune: pectin, soluble carbohydrates,or cellulose

Answer 51

soluble carbohydrates fastes (cellulose slowest)

Question 52

order these processed corn grains from lowest to highest total digestible nutrients (TDN): ground, high-moisure, steam-flaked, and cracked

Answer 52

cracked, ground, high-moisture, steam-flaked (these are increasing rate of fermentation, so could influence risk of acidosis)

Question 53

as minimum forage NDF decreases, minimum dietary NDF _____, maximum dietary NFC ________, and the minimum dietary ADF ________

Answer 53

minimum dietary NDF increases (need to get from a source other than forage), maximum dietary NFC decreases, minimum dietary ADF increases

Question 54

NDF concentration in the diet must be higher when forage is _________

Answer 54

finely chopped

Question 55

consider these 6 things when formulating diets at minimum concentration of NDF

Answer 55

base on composition of feed (not table values), particle size >3mm, grain source processing, feed as TMR, careful of feed mixing and delivery errors, and that it is better not to feed at the minimum NDF level

Question 56

what is effective NDF, eNDF

Answer 56

sum total ability of NDF in feed to replace NDF if forage or roughage so that %milk fat is maintained

Question 57

most sources of NDF from nonforage (eg. NDF from beet pulp or grain, rather than long coarsely chopped NDF) is significantly less effective at ____ than are forages

Answer 57

maintaining milk fat % (on average, non forage eNDF is only half was effective as NDF from forage, but listed cottonseed is an exception and has higher eNDF value than other non forages)

Question 58

what is peNDF (physically effective peNDF)

Answer 58

physical characteristics of NDF, especially particle size, that affect chewing activity and biphasic nature (gas and liquid) or rumen contents

Question 59

peak microbial protein production is about 4 kg/d. this will occur at what value of organic matter fermented in rumen per day?

Answer 59

25 kg/d (as organic matter in rumen increases, so does the microbial protein production, until that peak value. then after that drops off slightly)

Question 60

***pef should be _______ of ration DM for lactating dairy cows***

Answer 60

>21-22%

Question 61

why do we need a minimum NDF

Answer 61

rumen health

Question 62

why do we need a minimum NFC

Answer 62

for rumen fermentation (VFA and microbial protein synthesis) as well as for milk yield and protein. so, NFC is needed to supply energy to animal as well as the rumen microbiota

Question 63

availability of carbohydrates with fast degradation in the rumen, ie. NFC, will have what effects on microbes and the animal

Answer 63

increase microbial protein synthesis as well as increase supply of metabolizable protein to animal

Question 64

how does decreasing NFC in diet decrease milk protein production

Answer 64

decreased NFC --> decrease microbial protein synthesis --> decrease metabolizable protein supply --> decrease milk protein production

Question 65

what is optimum NFC in dairy cow diet

Answer 65

38-40% DM

Question 66

***an excess of NFC in dairy cow diet will have what effects? ***

Answer 66

decrease ruminal pH, promoting subclinical or clinical acidosis, decreasing the milk yield and fat content

Question 67

***an excess of NFC in dairy cow diet will have what effects? ***

Answer 67

decrease ruminal pH, promoting subclinical or clinical acidosis, decreasing the milk yield and fat content

Question 68

what should dairy cow poop look like

Answer 68

formed shape, see concentric rings

Question 69

what should dairy cow feed look like

Answer 69

variety of particle sizes, the long fibres shouldn't be super long or the cows will sort through them and not eat them

Question 70

what is metabolizable protein?

Answer 70

true protein that is digested postruminally and the component amino acids absorbed by the small intestine. ie. microbial protein + rumen undegradable protein + endogenous protein = metabolizable protein

Question 71

***how much protein does the dairy cow need? when does maximal microbial protein synthesis occur?***

Answer 71

maximum microbial protein synthesis at 22 mg ammonium per decilitre of fumes fluid. MINIMUM level is 5 mg N-NH3/dl in rumen fluid, about 7% CP, but want more than this ideally

Question 72

***who will produce the most microbial protein (in kg/d): a dry cow, a cow producing 50L milk/d, or a cow producing 10 L milk/d***

Answer 72

more milk = more microbial protein production. dry cows produce very little

Question 73

which NFC type promotes higher efficiency of luminal microbial protein synthesis, NDF or starch?

Answer 73

starch

Question 74

what are main 3 limiting amino acids in lactating cows?

Answer 74

methionine, lysine, histamine

Question 75

when is methionine limiting amino acid in dairy cows

Answer 75

when majority of the rumen undegraded protein is supplied by oilseed meal (eg. soybean or canola meal) or animal protein

Question 76

when is lysine limiting amino acid in dairy cows

Answer 76

when majority of the rumen undegraded protein is supplied by corn product

Question 77

when is histamine limiting amino acid in dairy cows

Answer 77

when grass, barley, or oat silage is in diet

Question 78

why should we avoid feeding excess protein in diet

Answer 78

energy intensive to convert to urea. (if we increase 4 mg/dl plasma urea N, corresponding loss of 200g of body fa or 1.5 L of milk. N is expensive to convert to urea). also negative effect on reproduction.

Question 79

protein: what crude protein (CP) level do we aim for? how much of this CP should be rumen degradable vs undegradable protein (RDP vs RUP)?

Answer 79

16-17% CP. 60-65% of CP should be RDP, 35-40% of CP should be RUP

Question 80

***we monitor protein levels in dairy cattle with what biochemical parameter? what level do we aim for?***

Answer 80

milk urea nitrogen (MUN) should be 12-18 mg/dl. milk protein also needs to be >3.2%

Question 81

***diets with excess CP (>19%) have a negative effect on reproduction. give a few specific negative effects related to reproduction (or other negative effects).***

Answer 81

increase blood urea, decrease uterine pH, chance uterine fluid composition, decrease plasma progesterone decrease conception rate, increase services per pregnancy, increase days open, increase embryonic loss

Question 82

give 4 benefits of fat supplementation

Answer 82

increase energy density, reduce heat increment, increase feed efficiency, decrease methane production

Question 83

give 2 drawbacks of excess fat supplementation

Answer 83

decrease rumen fermentable matter, decrease fibre degradation in rumen (especially with unsaturated fats), reduce milk fat percentage through altering fermentation

Question 84

how much fat to give in diet of lactating dairy cow

Answer 84

3-4% DM as supplemental fat; 6-7 ether extract in total diet DM

Question 85

what is TMR? give an advantage of using TMR

Answer 85

most dairy herds are fed this diet type. every bite is a complete, nutritionally balanced diet. make milk fat depression and other digestive upsets less likely to occur

Question 86

compare and contrast using a single-ration TMR vs several TMR-rations for a herd

Answer 86

single ration: simpler, formulated for needs of higher producing group (could lead to over conditioning of lower need groups), based on principle that higher needs cows will have higher DMI. multiple rations: can meet needs of different groups, reduces feed costs, and easier to control BCS, but requires moving animals (can cause stress) as their needs chance

Question 87

give two ways concentrate amounts can be fed to lactating dairy cows

Answer 87

tie-stall and stanchion barns (these involve manually dispensing the concentrate on top of the TMR) vs free-stall barns with a computerized concentrate feeder (program the allowances of feed)

Question 88

***what is a potentially disadvantage of using concentrate as a motivating factor for cows to enter the robotic milking system***

Answer 88

diet consumed may be different from what is formulated (1 kg of dispensed feed may replace 0.8-1.6 kg of the partial mixed ration, ie cows not eating to their needs)

Question 89

when there is a sudden increase in Ca demand from late gestation to early lactation, what disease can occur? give subclinical and clinical indicator (hint: give the blood value)

Answer 89

hypocalcemia (milk fever), a decrease in plasma Ca concentration. subclinical is total blood Ca 1.4-2.0 mol/L; clinical is <1.4 mmol/L

Question 90

subclinical hypocalcemia has what 4 negative effects on dairy cows

Answer 90

increase risk of metabolic and infectious disease, increase risk of reproductive disorders, increase early culling, decrease milk production

Question 91

calcium homeostasis: alkaline blood causes a conformational change in PTH receptors, causing what

Answer 91

loss of tissue sensitivity to PTH

Question 92

calcium homeostasis: hypomagnesia causes loss of tissue sensitivity to what

Answer 92

PTH

Question 93

what breed and age is most susceptible to hypocalcemia

Answer 93

older cows > heifers (heifer bones are more responsive to PTH and more receptors for vitamin D in intestine); Jersey cows more susceptible

Question 94

give 2 diet strategies to prevent hypocalcemia

Answer 94

low Ca diets or low dietary cation-anion diets

Question 95

excessive dietary intake of P increases the risk of what

Answer 95

hypocalcemia

Question 96

low plasma calcium stimulates ___ release, which acts to resorb calcium from bone and ____ renal absorption of Ca

Answer 96

PTH (parathyroid hormone); enhance

Question 97

high plasma calcium stimulates _____ secretion which lowers plasma calcium by limiting _______

Answer 97

calcitonin; bone resorption

Question 98

parathyroid hormone has what 2 functions

Answer 98

raise calcium via bone resorption and renal calcium reabsorption; stimulate vitamin D production by kidney

Question 99

prepartum dairy cow diets should be balanced for what 3 nutrients and 1 other factor to reduce the risk of hypocalcemia

Answer 99

Ca, Mg, P intake; dietary cation-anion diet value (details: Ca intake 50-70g/d; Mg 40-50 g/d; P <35/d; DCAD -150 to 150 mEq kg/DM

Question 100

diet DCAD should be adjusted to achieve average urinary pH of what in Holstein cows? what about Jersey cows?

Answer 100

6.0-7.0 for Holsteins, 5.5-6.5 for Jerseys (think, Jersey cows are little, so they have a little lower pH)

Question 101

***ketosis, which a majority of high-producing cows are likely to experience to some degree subclinically in early lactation, can occur is negative energy balance state due to ______***

Answer 101

excessive fat mobilization (end-products of liver fat metabolism are ketone bodies)

Question 102

how can ketosis be detected

Answer 102

blood, milk, urine, and smelling cow breath (sweet breath)

Question 103

how can ketosis be detected

Answer 103

blood, milk, urine, and smelling cow breath (sweet breath)

Question 104

you cow is off feed, constipated, depressed, loses some BCS, and is producing less milk. you smell her sweet breath and grab a confirmatory test and some treatment for her condition. how are you treating her condition

Answer 104

propylene glycol is preferred treatment, IV glucose may have some immediate benefit

Question 105

_________ administration to close-up dry cows reduces the incidence of ketosis

Answer 105

monensisn sodium

Question 106

you cow is off feed, constipated, depressed, loses some BCS, and is producing less milk. you smell her sweet breath and scribble the disorder you suspect on your SOAP, which is ______

Answer 106

ketosis

Question 107

most LDAs are diagnosed during what stage of a cow's life

Answer 107

first 2 weeks postpartum

Question 108

the abomasum can rotate under the rumen and omasum to the left or right, but usually rotates to the ___ side

Answer 108

left (90% cases)

Question 109

when excess gas collects in the abomasum and rotates under the rumen and then up on the left side of the body behind the rumen (which is emptier than usually due to decreased feed intake), this is known as ______ and surgical intervention may be required

Answer 109

left displaced abomasum

Question 110

how can LDAs be prevented, give at least 3 ways

Answer 110

prevent decrease in DM intake prevent hypocalcemia, promote adequate rumen fill, manage BCS

Question 111

what is the most common metabolic disorder in dairy cattle? give term and explain the condition

Answer 111

subacute rumen acidosis = pH of rumen between 5.2 and 5.6 for ***at least 3 hours*** in a day

Question 112

define rumen acidosis, including clinical signs

Answer 112

rumen pH below 5.0; this is less common but more serious than subacute rumen acidosis; causes elevated HR, diarrhea, depression, potential death if untreated

Question 113

what are at least 3 possible causes of rumen acidosis

Answer 113

decreased VFA production reducing absorption and buffering; excess grain or NFC in diet; rapid increase in dietary NFC, highly fermentable forages and/or insufficient dietary coarse fibre; insufficient rumen buffering due to inadequate chewing and salivation, cows sorting forage from diet

Question 114

incidence of subacute rumen acidosis is ****_______**** in early and mid lactation dairy cow

Answer 114

19-26%

Question 115

give at least 4 consequences of subacute rumen acidosis

Answer 115

feed intake depression, reduced fibre digestion, milk fat depression, diarrhea, laminitis, liver abscesses, increased production bacterial endotoxin, inflammation

Question 116

high levels of non-esterified fatty acids (NEFA) indicate a state of ne

Question 117

low levels of beta-hydroxy butyrate are acceptable during period of negative energy balance in dairy cows (small amount of body weight loss is acceptable). at what level of BHBA is excessive, indicating that the degree negative energy balance is too large?

Answer 117

> 1 mmol/L

Question 118

nonesterified fatty acid (NEFA) level limits are _____ prepartum and ___ postpartum

Answer 118

0.29 mmol/L prepartum and 0.57 mmol/L postpartum (it is normal to have some degree of negative energy balance postpartum; these are the limits)