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118 Cards in this Set
- Front
- Back
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When assessing dairy cow rations, what 3 components need to be assessed? |
1) Amount allocated 2) Provision of nutrients (ration balance) 3) Delivery system |
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For amount allocated, what is assessment based on? |
Estimation of dry matter intake (lactating cows) |
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What is the DMI equation? |
DMI (kg) = [2% x bodyweight (kg)] + [4% fat corrected milk (kg)/3) |
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What is the DMI (kg) of cows? |
DMI (kg) = 3 to 4%: low intake would be 3%; cows capable of eating 4% |
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What is the DMI (kg) of dry cows and calves? |
2% |
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What does poor rumen fill indicate? |
- Inadequate DMI - Lack of fibre - Poor appetite - Reduced palatability of feed |
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What is the target for rumen fill? |
3+/5 |
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Describe the signs of rumen fill that is 1 |
Hollow L paralumbar fossa (slab side, empty cows e.g. LDA) |
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Describe signs of rumen fill of 3 |
Average gut fill with fair feeding levels |
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What does a rumen fill of 5 look like? |
Distended fossa and rumen |
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How are pasture/feed residuals used to assess allocation of feed? |
Based on the amount of pasture left after herd has finished grazing a paddock/strip: high utilisation rates (>75 - 80%) indicate inadequate allocation of feed |
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In a linear bunk space, what is mm/head of space is required for cows? |
700mm |
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True or false: the feed bunk in lot feeding should never run empty |
True - feed bunk should never be empty |
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True or false: haystacks and corn cobs are available feed for cows in lot feeding |
False - these won't be eaten and are not available feed |
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What do excessive feed residuals suggest? |
- Palatability problems - Excessive fibre levels - Check rumen fill |
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What is the use of BCS in assessing nutrition? |
Tool to estimate body weight changes and body tissue reserves (medium to long term) |
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What is the recommended number of cattle to BCS out of a herd? |
Usual recommendation is to score 70 cows from herd; if score less, needs to be across the herd structure |
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What is the international scale for BCS? |
5 point scale |
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What 5 areas are assessed when BCS? |
1) Area between tail and pins 2) Inside of pins 3) Backbone 4) Hip 5) Depression between hip and pin |
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What 3 groups of cows should be BCS on a dairy farm for good herd information? |
1) Dry cows inc. springers 2) Cows near peak lactation 3) Cows at drying off |
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What is the maximum BCS loss for cows near peak lactation? What are the implications if losses are greater than this? |
Cows should lose a maximum of 0.75/5BCS only; losses >0.75 will impair reproductive performance |
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What BCS should cows at drying off be in relation to BCS at calving? |
Cows at drying off should be within 0.25/5 BCS of that at calving |
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What is the "quick and dirty method"? |
It is a tool used in field for crude ration analysis based on an E (ME) basis |
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What are the components of E = MC^2 in the "quick and dirty method" equation? |
E = Energy M = Milk production C = Condition (maintenance) 2 = Too much walking |
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What are the energy outputs used to estimate energy in the "quick and dirty method"? |
1) Maintenance 2) Milk production 3) Walking 4) Pregnancy 5) Liver-weight - gain and loss |
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What is the maintenance (MJ/kg) for 600kg cow? |
70MJ for 600kg +/-5MJ/50kg |
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What is milk production (MJ/L) of Holstein compared to Jersey cow? |
Holstein = 5MJ/L Jersey = 6MJ/L |
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What is the MJ/km for walking? |
3MJ per km walked |
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What are the energy requirements of pregnancy: 5 months, 5 - 7months, 8 months, 9 months? |
5 months = 3MJ/day 5 - 7 months = 11MJ/day 8 months = 19MJ/day 9 months = 35MJ/day |
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What MJ is needed for 1kg gain during lactation compared to 1kg grain during dry period? |
Lactation = 34MJ/1kg gain Dry period = 43MJ/1kg gain |
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True or false: During lactation more MJ are required per 1kg gain compared to gain during dry period |
False - 43Mj/1kg is required in dry period compared to 34MJ/1kg in lactation |
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How much MJ is available for each kg that is lost? |
28MJ available for each kg lost |
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What are the energy inputs into the "quick and dirty method"? |
1) Grain 2) Hay 3) Silage 4) Pasture 5) Brewers grain |
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What is the MJ/kg of DM for grain (90% DM)? |
11MJ/kg DM |
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What is the MJ/kg of DM for hay (90% DM)? |
7 - 10MJ/kg DM |
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What is the MJ/kg of DM for silage (35 - 45%DM)? |
8 - 10.5MJ/kg DM - depends on quality: poor grass silage = 8.5MJ/kg DM; good maize silage = 10.5MJ/kg DM |
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What is the MJ/kg DM of pasture (15 - 25%DM)? |
9 - 11MJ/kg DM |
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What is the MJ/kg DM of Brewers grain (35% DM)? |
10.5MJ/kg DM |
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What are the basic early lactating dairy cow requirements? |
CP = 18% (13% RDP, 5% UDP) NDF minimum = 30% peNDF = 24% ADF = 22 - 24% DM ME = 11.5MJ/kg NFC = 36% Crude fat = 2 - 5% DMI = 3 - 4% BW (usually between 18 - 24kg) |
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What factors should be considered when supplementing with concentrate? |
- Amount and type of supplementation - Form of supplement - Pulsar effect - Fibre concentration in diet |
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True or false: whole grains are poorly utilised |
True |
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What processing can be done to grains to make them more efficiently utilised? |
- Cracked (3 - 4 pieces best) - Ground - Rolled - Heat treated - Chemically treated |
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Form of grain treatment affects what? |
Consumption rate |
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What are the problems with feeding grain? |
1) Grain by itself is not ideal 2) Fibre in the pasture may not keep the rumen stable 3) Returns must be assessed in reference to milk cost |
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What is "pulsar effect"? |
In the grazing cow there is a constant and marked daily change in the rumen environment due to the way cows are fed |
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Explain how changes in feeding overnight, at milking and during grazing leads to "pulsar effect" |
Overnight = hay feeding: high fibre, low ME, low CP Milking = concentrates: low fibre, high ME, high CP Grazing = pasture: moderate fibre, moderte to high ME and moderate to high CP |
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How is "pulsar effect" best minimised? |
By feeding TMR |
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What are the advantages of feeding TMR? |
1) Less ability to select out certain feed 2) Safer for high grain diets 3) Total control of nutrient intake of cows within the limits of individually variability in intake 4) Combination of concentrates and roughage = stable rumen fermentation 5) Opportunity to feed by-products 6) Highest level of utilising pastures via mechanical harvesting of forages 7) Minimises energy expenditure with walking |
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What are the disadvantages of feeding TMR? |
Cost of mixer wagon/infrastructure |
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Why is fibre levels in ration so important? |
Affect rumen function: - Physically - Biochemically - Fat % in milk |
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What is the minimum NDF in a ration? |
30% |
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What is minimum peNDF in ration? |
24% |
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What is the minimum length fibre should be? |
4cm |
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Explain reasons why heifers on TMR are still at risk of acidosis |
- Heifers bunted out of way - decreasing bunk access - Cows sort feed and seek out forage so that heifers may get a different diet and have more access to CHO - Heifers are nervous eaters and don't chew feed well |
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When production of heifers is 80% of adult cows it is a warning sign of a problem. Explain why this is common in heifers on pasture based systems |
Often 60% of the herd (cows) have already exited the dairy and are on pasture before the first heifer arrives |
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What 2 forms of protein are needed in ration? |
1) Rumen degradable protein (RDP) 2) Undegradable protein (UDP) = rumen bypass protein e.g. Brewers grain |
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What fraction of CP needs to be UDP? Why is this important in dairy cows? |
1/3 of CP needs to be UDP; high producing cows need a source of UDP to milk to potential |
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Most cattle feeds are low in UDP, what are good sources of UDP? |
- Corn - Brewers grain - SBM - Corn gluten feed |
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Explain protein metabolism |
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How does protein requirements differ between early lactation/high producers, mid - late lactation and dry dairy cows? |
Early lactation/high producers = 18% CP Mid - late lactation = 14 - 16% Dry dairy cows = 10 - 16% depending how close to calving |
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What is the recommended faecal score? |
3: porridge-like consistently (may stick to boot, forms a soft pile 3 - 5cm high with several concentric rings |
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What are the methods used to assess ration balance? |
1) Computer models 2) Manually using Pearson square 3) Faecal assessment 4) Cud chewing 5) Locomotion scoring |
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Describe faecal score 1 |
No formation of cow pat on ground Scouring as cow walks May contain grain Thin fluid arcs Green |
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Describe faecal score 2 |
Minimal formation of cow pat on ground Loose, splatters May contain grain |
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Describe faecal score 4 |
Thick Dry manure Forms piles 5 - 8cm high May contain whole grain |
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Describe faecal score 5 |
Firm cow pat Well formed No evidence of excessive liquid component Faeces are similar to horse poo in consistency Forms piles >8cm high |
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What is cud chewing an indicator of? |
Effective fibre |
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At rest, what % of cows should be cud chewing? |
50 - 70% |
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What % of cud chewing may indicate a problem e.g. subclinical or clinical acidosis? |
<50% |
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What is locomotion scoring based on? |
1) Position of cows back when standing and walking 2) Position of feed and favouring of feet when walking |
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How can average locomotion scores be calculated? |
Average locomotion scores for herds can be calculated by scoring a proportion of herd at random |
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Describe locomotion score 1 |
Stand and walks normally, all feet placed with purpose |
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Describe locomotion score 2 |
Stands with flat back, arches when walks Gait slightly abnormal |
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Describe locomotion score 3 |
Stands and walks with arched back Short strides with one or more legs |
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Describe locomotion score 4 |
Arched back standing and walking One or more limbs favoured but at least partially weight bearing |
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Describe locomotion score 5 |
Arched back Refuses to bear weight on one limb May refuse or have problems getting up |
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What are the 3 critical factors for ration delivery? |
1) Grain type 2) Processing (target >90% cracked grain 3 - 4 pieces) 3) Delivery/access |
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Define ration delivery |
The way forage is provided to the herd including access time and method of delivery |
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What factor will impact ration delivery? |
- Distribution of mixed feed in dairy feeding systems and TMR - Chop length in TMR - Provision and access to water - Potential for cows to receive x2 the concentrate allowance in bail during milking - Staff changes - Changes in amounts of mixed feeds being fed without addressing concentration of additives |
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The lactation curve assesses the relationship between what 3 components? |
1) Milk yield 2) Body weight 3) Appetite |
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Describe body weight change in the lactation curve |
Body weight decreases until nutritional requirements of cow are met by nutrients in ration |
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Describe changes to appetite during lactation |
Appetite increases slowly to reach peak ~4months postpartum |
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Describe how milk yield changes with lactation |
Peaks ~6 - 10weeks postpartum and then decreases by ~10% per month |
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When does milk yield peak in lactation? |
6 - 10weeks postpartum |
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By what % does milk yield decrease after 6 - 10 weeks postpartum |
10% per month |
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Early peaking, poor persistency and drop in BCS reflect what problems with ration? |
Energy deficiency |
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Low peak in milk yield but good persistency reflects what problem with ration? |
Protein deficiency |
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How dairy cows are fed can affect 4 areas of production, what are these? |
1) Milk composition 2) Milk production 3) Fertility 4) Disease status |
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What cows are the most efficient milk producers? |
Cows in early lactation |
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What happens if cows enter the milking herd in low BCS and are fed low plane of nutrition? |
There is a cumulative loss in milk yield |
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When resources are limited, what group of cows is it important to adequately feed first? |
Cows in early lactation |
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What clinical evaluation tests can be useful for assessing dairy nutrition? |
1) Blood 2) Serum 3) Urine 4) Milk composition |
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PCV <28 (anaemia) is caused by what? What is it associated with? |
Caused by: - Suboptimal protein metabolism - Parasite infestation Associated with infertility |
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What is a high BUN associated with? |
Excessive RDP |
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What is a useful measure of protein status? |
Serum albumin |
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How does serum colour indicate B-carotene levels? |
Deep golden colour = high levels Pale straw colour = low levels |
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What is urine assessment used for on dairy? |
1) Ketones 2) Urine pH indicates effectiveness of transition diet |
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Describe method of assessment of urine pH for transition diet |
Diet must be fed for 2 - 3days and urine sampled at 4 - 8hrs after feeding A high urine pH (alkaline) indicates problem with transition diet |
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What does milk composition indicate? |
Nutritional status of herd |
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What are high milk fat tests associated with? |
1) High fibre levels in diet 2) Weight loss and excessive fat mobilisation 3) Low fermentable starch and CHO 4) Feeding fat/oil 5) Deprivation of water/poor quality water |
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What will happen to milk yield/composition if there is deprivation of water/poor quality water on offer? |
Milk yield will decrease dramatically coupled with an increase in both fat and protein content of milk |
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What does a low milk fat indicate? |
1) Breed differences 2) Stage of lactation 3) Low fibre intake 4) Highly processed concentrate sources resulting in acidosis 5) Infrequent feeding with concentrates 6) Use of ionophores 7) Poor BCS 8) High concentration of fat in diet 9) Rapid introduction/increase of starchy concentrates 10) Lack of buffers or modifiers in diet 11) High environmental temperatures and humidity 12) Increasing age of cow/herd 13) Reduced pasture palatability/availability 14) Low dietary CP and poor fibre digestion |
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What does a low milk protein indicate? |
1) Stage of lactation 2) Low energy density of diet 3) Low energy intake 4) Low protein intake (<14% CP) 5) Increasing age of cow/herd 6) Mastitis 7) High milk production 8) High fat in diet (>5% ration) 9) Acidosis in herd |
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When assessing quality of the concentrates what is assessed? |
- Vermin damage? - High % of cracked grain? - Fullness of grain e.g. oats vary - Mould, ergot fungal or other infections? - Colour - Adequacy of storage - Evidence of age |
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What is assessed when looking at quality of hay? |
- Colour - Leaf content and stem thickness - Evidence of flower or seed - Amount of weathering - Mould, fungal growth or spores - Evidence of undesirable plants e.g. thistles, Patterson's curse |
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What is assessed when assessing quality of silage? |
- Colour - Smell (should have pleasant "bitter-sweet" smell) - Packing - Chop length/moisture level - Stem development of plants |
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What does brown/black hay or silage suggest? |
Heat damage |
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What does tobacco smelling silage indicate? |
Heat damage
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What does vomit smelling silage suggest? |
Poor fermentation resulting in butyrate rather than lactate and poor quality silage |
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What should the chop length be of pasture hay compared to corn silage? |
Pasture hay (20% DM) = 15 - 20cm Corn silage = <2 - 3cm |
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What is assessed when assessing quality of pasture? |
- Density of sward - Age of sward - Amount of death and decay - Competing species - Leaf to stem ratio - Grazing pressure (over/under utilisation) - Presence of undesirable plants (thistles) - Soil quality - Plant disease - Colour - Drainage |
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How can peNDF of pasture be estimated? |
Break handful of pasture to estimate sheer strength = estimation of peNDF |
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How is amount of pasture utilised estimated? |
Amount of pasture utilised is estimated by cutting pasture in a fresh paddock down to grazing/cutting height |
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How is amount of pasture present/available estimated? |
Amount of pasture present/available is estimated by cutting pasture in a fresh paddock down to the height the pasture could be grazed ( 1 - 3cm) |
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On a routine farm visit, what 5 components should be in assessment of lactating cow herd? |
1) BCS 3) Rumen fill 4) Faecal score 5) % cud chewing at rest |
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What 2 components of routine farm visit make up assessment of dry cow herd? |
1) BCS 2) Rumen fill |
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What 5 components are involved in assessment of transition cow herd? |
1) BCS 2) Rumen fill 3) Locomotion scoring 4) Faecal score 5) Urine pH |
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Describe the routine farm visit |
- Assessment of lactating cow herd, dry cow herd, transition cow herd - Evaluate milling of supplementary feeds - Evaluate delivery (mixing, access, timing) - Evaluate the bail feeders for left over concentrates between milking - Inspection of all supplementary feeds to check for spoilage, contaminants, quantity - Assessment of pastures/forage crops in terms of quantity and quality, projected growth rate and calculated feed budget - Sampling of pastures and/or supplementary feeds if necessary
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