Sheep Flashcards
1
Q
What factors affect the choice of type of sheep enterprise? Eg. Breeding, wool, meat.
A
Potential profit
Personal preference
Location/climate/feed supply/market access
Capital to buy stock/exposure to high prices
Attitude to risk - disease, ability to de stock, etc.
Control of genetics
Facilities - fencing, shearing shed
Availability of labour
2
Q
What is the average shearing rate?
A
$7 per head
3
Q
How long do you generally keep ewes?
A
Keep for 5-6 years
Good ewes can remain productive for up to 10 years.
4
Q
How is wool sold?
A
$/ha = quantity x quality
Marketed mainly via wool brokers
In the future, expect move towards electronic auction which will greatly decrease marketing costs.
5
Q
What are the most important factors to determining value of wool?
A
Micron, strength, vegetable matter, length, staple, marketing factors, mid breaks, colour and style.
6
Q
Describe how wool micron drives price.
A
The smaller the micron (diameter) the higher the price.
This price has increased over the last 10years.
7
Q
Define what a ‘lamb’ is.
A
Up to 12 months old, hasn’t yet cut 2 teeth.
8
Q
How is lamb marketed?
A
Can be through saleyards (stock agents-paid for weight and fat).
Over the hook - abbotoir
Contract - weight and fat price grid with agreed delivery date. Discounts if don’t meet terms, paid for weight, not per head.
Private/paddock sales
Electronic
9
Q
What is carcass weight in sheep generally estimated to be about?
A
CW - slightly less than 50% live weight.
10
Q
Describe the requirements of lambs for different markets.
A
Domestic - 17-22kg CW, 6-15mm GR (12th rib), fat score 2-3, first or second cross lambs.
Supermarket - 18-22kg, GR 7-12mm, fat score 2-3, second cross preferred.
Food service - 20-25kg, GR 7-15mm, fat score 2-3.
Heavy export - 20-30kg, GR 6-20mm, fat score 2-4
Light export - 10-14kg, up to 10mm fat (very low).
11
Q
When is the lamb price usually at a premium?
A
In winter because numbers are lower.
Currently about $6/kg currently.
12
Q
What are the main profit drivers in sheep systems?
A
Quantity sold/ha x $ value (stocking rate and weaning % important).
Cost of production (efficiency) - match feed supply to demand (cheapest feed is pasture), labour efficiency, enterprise scale (spread overhead costs).
13
Q
What differences are there between the top 20% of the industry and the remainder?
A
Top 20% have higher stocking rates therefore higher lamb marking %.
As a result they have a higher GM$/ha/100mm of rain.
14
Q
True or false, low producers cost as much to run but produce less, therefore they lead to decreased income and increased cost of production.
A
True
15
Q
How do we get the right sheep for our herd?
A
Selection - aim to improve flock
16
Q
What should breeding objectives consider?
A
Direction of the enterprise
Aim to improve profitability - increase output, decrease input.
Consider all components and their associated economic weights.
17
Q
Define repeatability.
A
Extent to which superiority in one year is maintained in the next.
Ex. Phenotypic variation in fleeces weight.
18
Q
What does GFW stand for?
A
Greasy fleece weight.
19
Q
What does h2 stand for?
A
Heritability
20
Q
What is selection differential?
A
The difference in fleece weight between selected individuals and the whole flock.
21
Q
How do you determine EBV’s using an equation?
A
EBV = heritability x predicted superiority
Have to make if specific for a specific trait, eg. Greasy fleece weight.
22
Q
What is genetic correlation?
A
The extent to which two traits are controlled by the same set of genes.
To what extent will selection of individuals of high performance for trait 1, give rise to progeny of high performance for trait 2.
23
Q
How do you determine selection index?
A
EBV x REV for GFW, FD and BW all added together.
Gives overall genetic merit in $.
24
Q
Describe the breeding structure of the merino industry.
A
Pyramid with parent studs at top (small number with big influence on genetics), then daughter studs(only buy from parent studs), general studs (buy from only one or multiple daughter studs) and commercial studs at the base.
Has a massive influence on how the genetics are passed onto the wider industry.
25
How do you make genetic progress?
Objective - know what traits to select for.
Know which traits have adequate heritability - fertility is desirable but has low heritability.
Use effective selection tools - ASBVs if available.
Use selection pressure on desired traits.
26
Briefly describe the open nucleus format used within the Australia Merino Society.
Central nucleus which produces Rams available to all members of a cooperative.
Not widely used.
27
Describe the effect of selection on Australia's sheep industry.
Allows for selection differential - superiority of selected animals over average.
Heritability - degree to which superiority transferred to the next generation.
Response due to selection = h2 x (selection diff./2)
28
What are the three most important factors to consider when deciding where to go with your breeding objectives?
Trait measurement - which traits, which animals, males or females, progeny test.
Estimation of breeding value - phenotypes, pedigree, BLUP, genetic markers.
Reproductive technology - artificial insemination, multiple ovulation/embryo transfer.
29
What is generation interval?
Average parent age when offspring are born.
Longer generation interval means slower response to selection at the same stocking density.
Different for Rams and ewes.
Smaller generation interval has faster progress however less superior animals are selected.
Merinos; Rams 1-2 matings, ewes 4-5 matings.
30
Describe a sheep enterprises genetic improvement options.
Remain with current stud, change ram source or change ram and purchase ewes.
Ram source has a large impact, merino flocks are typically bred on a bloodline.
What ever stud is chosen then your genetics will follow that studs breeding objectives.
Changing the ram and purchasing ewes allows rapid progress but is costly.
31
How can you identify better studs/individuals when changing your ram source?
```
Do bloodline comparisons - wether trials.
Look at the stud breeding objectives.
Sire evaluation
On farm trials
Merino select.
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32
What do bloodline trials do?
Aim to compare performance in the same environment/management.
Eg. Fibre diameter, fleece weight and $GM/DSE
33
What factors shod you consider when choosing a bloodline?
Define your breeding objective
Benchmark current bloodline performance
Consider all traits
Where are the possible bloodlines heading?
Constraints - price, availability, distance, available information
34
What is a central test sire evaluation? Discuss this.
CTSE is the breeding performance of individual sires measured by evaluating progeny.
A sires progeny performance is expressed relative to other sires.
Various test sites across Australia - each has annual mating of 10-16 sires. Each side mated to about 50 ewes that are representative of the strain - produce at least 25 progeny.
One link sire is mated for each 7 sires at a site - act as genetic connections between years and sites.
Progeny performance is assessed at 10-16 months (1st) and 17-24 months (2nd); includes fleece testing and visual by sheep classers.
35
What is sheep genetics Australia? What is their mission and how are they going to achieve it?
Mission - genetic improvement for a sustainable and profitable Australian sheep industry facilitated by the worlds best sheep genetic evaluation system.
Achieve this through common language (ASBVs), regularly updated and accessible information, range of commercial traits for different ages, accuracy and across-flock linkage, fair pricing, QA standards, breeders have ownership and disclosure of data.
>80% of meat sheep breeds evaluated, >50% of merinos evaluated.
36
What are ASBVs?
Standardised breeding values.
Minimum of 47, based around 0.
Accuracy values.
If the data doesn't meet quality assurance and accuracy then it is reported as flock breeding values (FBVs).
Need to compare ASBVs to the current average.
Negative is not always bad.
37
What is an index?
Combines the ASBVs for several traits into one value.
Can be available to suit a range of different breeding programs.
Allows a quick selection guide to narrow down which Rams to look at.
38
What is micron premium?
Indicator of economic advantage of reducing fibre diameter.
Strong relationship between micron and price-the finer the wool, the higher the price. As micron increases, the fibre diameter decreases.
Higher premiums have more emphasis on diameter.
Low premiums have more emphasis on fleece weight.
39
What are some of lamb plans terminal indices?
Carcase plus - wwt (weaning weight), pwt (positive weaning weight-most emphasis), fat and emd (eye muscle depth). Designed for high growth and muscle depth with leanness.
Trade $ index - pwt, fat, emd. Target 19kg Carcase.
Export $ index - pwt, fat, emd. Target 26kg Carcase.
Lamb 2020 index - bwt, wwt, pwt, fat, emd, wec. 22kg Carcase lamb bred from merino or first x ewe.
40
What are lamb plans maternal indices?
Maternal $ index (MAT$)
Dual purpose $ index (DP$)
Self replacing Carcase $ index (SRC$)
41
What is the maternal $ index aimed at?
Aimed at maternal breeds in place of the breed specific indexes.
Balances the key economic traits relevant to most maternal breeds.
42
What is the dual purpose $ index aimed at?
Aimed at self replacing maternal flocks with additional focus on wool quality.
Has the same breeding objectives as maternal $ index, with additional moderate emphasis on improving greasy fleece weight and a small emphasis on reducing micron.
43
What are the aims of self replacing Carcase $ index?
Used by breeds included in the terminal analysis with the intention of producing a self replacing flock with a strong emphasis on Carcase traits.
Has the same breeding objectives as the maternal $ index except that removal of economic values for fleece traits. This removal of selection pressure for fleece traits allows higher gains to be made for growth and Carcase traits.
44
What is the purpose of selection demonstration flocks?
Aimed to evaluate and demonstrate the strengths and weaknesses of merino selection methods.
Methods are based on the use of sheep classers, skin based selection, objective measurement systems and tools.
45
Discuss practical sheep selection.
Measured information on important traits from raw or ASBVs.
Visual inspection for faults and non measured traits.
Emphasis depends on your breeding objective, cost, ram/ewe ratio (selection pressure).
46
Discuss the selection of flock ewes.
Usually select before first joining - close to 18 months.
Number of replacements depends on number being culled.
Visual measurement
Prerequisites - >15 months, >4 months wool (shorn once), same age and history.
Overall quality.
Class to your breeding objective
Older ewes culled annually on health (udder, teeth, condition).
47
Discuss the selection of flock Rams.
How many are needed?
Choose them from a stud that matches your breeding objective.
Overall impression
Rank/class into tops and seconds based on measurements/index and visual.
Draft tops and seconds off and inspect.
Ram auction sales - competitive, value for $
48
What does the number of lambs sold per ewe result from?
Ewes mating, ewes conceiving, level of embryo mortality, ewes pregnant, ewes with multiple foetuses, lamb survival to weaning/market, and weaker survival.
49
How long is a ewes gestation period?
5 months.
Lamb at day 147.
Embryo implants at day 45.
50
When does weaning usually occur in sheep enterprises?
From 8 weeks depending largely on the farm.
| Day 60-120 post lambing.
51
How do you measure reproductive performance?
Weaning %, marking %, reproduction rate, fertility, fecundity.
52
How do you determine weaning %?
Lambs weaned/ewes joined
53
How do you determine marking %?
Lambs marked/ewes joined
| Can vary between the number of pregnant ewes or the number of ewes mated depending on the farmer.
54
How do you determine reproduction rate?
Live lambs at joining/ewes joined
55
How do you determine fertility?
Ewes lambing/ewes joined.
56
How do you determine fecundity?
Average litter size of lambing ewes.
57
What is a normal level of reproduction in sheep flocks?
For adult merinos joined in Autumn expect a marking % of 95-100%.
Maiden ewes 75-80%.
Varies greatly depending on climate, environment, etc.
Crossbreed ewes will have higher % as they have higher ovulation rates.
58
What can be some reasons for high return to service rates in ewes?
Poor ram fertility.
| Oestrogenic factors in pasture - clovers.
59
At what age do Rams reach puberty? How long are they usually kept in the flock?
Puberty at 6 months.
Normally sold/bought at 12-15months, common to buy new Rams yearly.
1/3 Rams over 7 years have low fertility, this is quite old for a ram and so is unusual to see this issue.
60
Discuss important factors to consider in terms of ram health.
4 Ts - teeth, tossle, toes, testes.
Disease - buying from saleyards is high risk, better to buy direct from stud where disease status can be confirmed. Severe production limiting factor if not managed.
Conformation
Acclimatisation, heat stress.
Shearing - 2-4 months wool at joining as is less weight to carry and decreased susceptibility to fly strike.
Condition score - good but not fat.
Spermatogenesis - 48 day cycle
Nutrition - sperm production is related to teste size and nutrition. Feeding lupins (500g/d 7wks prior to joining increases sperm-safe and low risk of acidosis compared to other grains).
Genetics - scrotal size, high wrinkle leads to increased chance of heat stress.
Season
Joining % and length of joining - 2 opportunities to mate, 5-6wks in Autumn, 8 wks in spring.
61
Discuss oestrus in ewes.
```
Not fertile = not pregnant
Cyclic breeders - repetitive 17d oestrous cycle.
In oestrus (heat) for about 1 day in each cycle.
Oestrus is influenced by season - short day breeders.
Can be influenced by age (maidens have shorter heat), breed (merinos easier than European breeds), ram effect, lactation and artificial means.
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62
Briefly describe the differences between merinos and British breeds in terms of ewe fertility.
British breeds undergo period of total anoestrus while some merino ewes may continue cycling during anoestrus.
63
Describe the ram effect.
Presence of the ram accelerates hormone activity leading to ovulation earlier than without ram.
Won't work in Autumn as ewes are already cycling.
Merinos more susceptible to this than British breeds.
64
What are the management factors to consider in terms of ewe fertility?
Ewes usually joined once annually - hard to meet nutritional requirements if more frequent.
Age - puberty reached as early as 6 months (cross breds), join at 18months but can be earlier provided nutrition is good.
Nutrition - minimum CLW of 40kgs (starvation level), be aware of minerals and plant oestrogens.
Health
Genetics
Lactation - lactational anoestrus occurs for up to 7 weeks post lambing.
Temperature - >32c can lead to heat stress which decreases oestrus behaviour and fertilisatio. Increased failure and embryo loss as well as increased returns to service.
65
How can you identify low fertility?
Preg scanning - 60d after Rams are removed
Wet/dry udders at marking.
Fertility has very low heritability and repeatability factors, more a function of environmental and genetic factors.
66
What two factors affect ovulation rate the most?
Genetics - breed, age (maidens lower), stage of season (ovulation rates can change).
Nutrition - can be static (2-4% increase/kg LWT), dynamic (flushing), or immediate/acute (flushing-type of feed such as lupins).
67
What is a key driver of reproduction rate?
Condition at joining
68
True or false, it is cheaper to maintain, rather than try to put on condition.
True
69
What is the correlation between condition score and the probability of dry, single or twins?
Ewes in higher condition score at joining conceive more lambs.
Increased probability of twins.
70
What is the optimum condition score in terms of reproduction rate?
3
71
How can you use CS to manage repro?
CS is accurate, reliable tool for managing ewes to target.
Quick - 25 random animals is enough for determining the average of the flock.
Need to be familiar with absolute scores to manage targets.
72
Discuss the dynamic effect and how it affects ovulation rate.
The dynamic effect is the gaining of weight before joining increases ovulation rate.
Can be facilitated by flushing; feeding 10-14d into cycle for 9days increases ovulation, however requires synchronisation and is costly.
Can use lupin or good quality, live pasture (cheaper).
In unsynchronised ewes you can flush still; flush 7days before and first 7 days of a 5 week joining.
73
Discuss oestrus synchronisation options for ewes.
Progesterone - not common in commercial, remain in for 2 weeks, ewe in oestru 2-3d after removal.
Prostaglandin - induces luteolysis, 2 doses.
For ewes in seasonal/lactational anoestrus a PMSG injection is required.
Fertilisation can be decreased due to reduced sperm transport - except when AI used.
Ram effect can be used.
Regulin/melatonin - administered 30-40d pre joining in anoestrus ewes.
When sync is used may need to increase ram numbers (10%) to cover all ewes as they are on heat at the same time.
74
Discuss embryo mortality.
20-30% of embryos are lost in first 30days. Won't notice if before day 11 as keeps cycle length normal.
After 30d you see some small losses.
Difficult to distinguish between embryo loss or fertilisation failure.
Age, stress, breed, under/excess nutrition, oestrogenic clovers, anthelmintics can all have an effect.
75
In what ways can nutrition be managed to decrease the incidence of embryo mortality?
High dietary N reduces embryo survival.
Excess energy can increase embryo mortality, seems to have a negative effect on progesterone levels.
Grazing Lucerne doesn't increase mortality.
76
When is peak energy required for a lambing ewe?
During lactation
| Requirements are 3x that of dry ewes.
77
Discuss nutritional requirements during pregnancy in terms of ewe survival.
Foetus has high glucose demand - energy and protein requirements increase rapidly in final trimester (last 6wks).
Late pregnancy sees fat mobilised for energy.
Under nutrition causes reduced ewe fitness (increased dystocia, decreased lamb and ewe survival).
Pregnancy toxaemia can occur in under or over nourished ewes.
78
What effects can overfeeding have on ewes?
Causes them to be too fat at lambing (CS4+).
| Loss of appetite, dystocia, preg toxaemia.
79
Which factors influence lamb survival at birth?
Birth weight, fat reserves and colostrum production.
80
Discuss the relationship between lamb birth weight and survival.
Graph.
As birth weight increases, survival increases.
Low survival at low birth weight as these are more likely to be twins in undernourished ewes.
When birth weight goes above 5kg survival begins to decrease again, this is due to increased chance of dystocia.
81
How can nutrition of the ewe affect lamb birth weight?
Depends on level of restriction.
D50-90; can affect placental weight, moderated by CS, and age of ewe.
Last trimester; fat ewes I'm energy deficit may be able to buffer foetal growth better, whereas thin ewes may eat more but partition to maternal live weight rather than the foetus.
82
Describe nutritions role in colostrum production.
Poor nutrition delays lactogenesis.
30% of ewes have insufficient colostrum at birth.
Colostrum levels can be doubled by feeding lupins, barley, maize or improved pasture 1-2wks before parturition.
If ewes are in good condition and on good quality pasture feeding more may be ineffective and not cost effective.
83
Does nutrition influence the lifetime performance of progeny?
Yes
84
What influences wool production and quality?
Genetics - select productive sheep.
Nutrition - quantity x quality pasture, supplement only for wool growth is likely to be ineffective, stocking rate, feed base, match supply to demand.
Sex
Age
85
How do you determine the $/ha?
$/ha=kg CFW/ha x value
86
Describe follicle development in the embryo and the effect nutrition can have on this.
Primary follicles develop 50-95d pregnant.
Secondary 95d to birth.
Maturation of follicles completed post birth.
Nutritional restriction during pregnancy can reduce adult wool by 8.5%.
Nutrition restriction in the few weeks after birth can reduce adult wool by 12%.
87
Can age influence wool quality and quantity?
Yes.
| Micron increases with age.
88
What factors determine the optimum flock structure for profit?
Enterprise (wool or lamb)
Relative income (wool or meat)
Cost of replacement ewes
89
Which flock structure factors affect production?
Age effects on wool quantity and quality.
| Age effects on reproduction - no lambs weaned, ewe peaks at 6yrs.
90
What is wool quality?
Trait which alters processing performance or end use.
$ wool = CFW x (value + premiums - discounts)
Traits include; fibre diameter, staple strength, position of break, percentage of mid breaks, staple length, vegetable matter, other (stain, cott, etc.)
91
What effects does reproduction have on wool growth?
Fleece weight often reduced.
Staple strength often reduced.
Fibre diameter may be reduced.
92
What are the different positions of break?
Tip - <33%
Mid - 33-66%
Base - >66%
93
What has the largest impact on staple strength in late pregnancy?
Restricted nutrition
94
Reproducing ewes wool is typically....
Less wool
Finer fibre diameter
Shorter staples.
Lower staple strength.
95
After ewes, which is the second most likely class to have trouble with reduced staple strength?
Weaners.
Can supp feed to improve this;
Survival - lupins 20.5kg/had
Traditional - lupins from mid February 28kg/hd
Recommended - lupins from clover wilting 32.5kg/hd
96
List some suggestions for improving staple strength.
Limit fibre variation in diameter via preventing rapid increases in diameter in spring, break of drought or lactation, reduce the 'trough' in diameter by supplementary feeding, selecting for sheep with lower CVFD.
Alter the time of shearing to limit the processing effects of tender wool.
97
List some factors that are important for wool quality and what effects them.
Fibre diameter - genetics, nutrition, age
Staple length - nutrition, genetics, timing of shearing
Vegetable matter - pasture composition, grazing management, shearing time
Colour, pigmented fibres, fleece rot, CVFD
Cott - health management
98
What are factors to consider for management for lamb quality.
Genetics - growth rate, fat, meat yield heritable
Age - Carcase size, fat content, lamb hogget or mature.
Sex
Meat Standards Australia chekclist
Juiciness - no breed or diet defects, correct pH (high due to poor nutrition can result in darker meat).
Flavour - mutton, breed, age, high legume diet
Tenderness - breed, age, diet
Colour - increases with age, breed, diet, pH, dietary antioxidants
99
What are the 4 constraints to pasture intake?
1. Animals capacity to use energy
2. Properties of the feed/pasture
3. Pasture distribution
4. Environmental factors
100
What kind of %BW would you expect as feed intake for ruminants?
3-4% BW
101
What limits production?
Pasture intake
102
What is voluntary feed intake affected by?
Ingestion rate = bites per unit of time x intake per bite
| Intake = ingestion rate x time spent grazing (13hrs max)
103
Elaborate on constraints to Intake - pasture distribution.
Pasture mass - intake increases to a threshold of about 2tonne DM/ha under continuous grazing and 50-100g OM/kg live weight for strip grazing.
Sward structure - height (bite depth and area increase with height) and density (bite size increases with increased density).
Lower quality pastures (<40% digestibility) - more selection which increases grazing time.
Spatial distribution - alters grazing time, trough placement
Distance to water
Palatability factors
104
How does seasonal variation in pasture influence intake?
Quantity varies between months and location.
Quality declines with maturity or high moisture content can limit DM intake (fills up rumen).
Varies with species
105
List the environmental constraints to intake?
Day length - grazing time reduced due to lower energy demand.
Temperature - change behaviour and grazing time; colder increases intake, warm decreases intake.
Rain - decreases intake
Shearing - increases intake due to loss of insulation.
106
What are some general considerations/rules to follow when assessing pasture?
Forage allowance should be less than twice the potential intake.
Assess the proportion of leaf vs stem and green vs dead.
Species - upright are easier to graze.
Degree of soiling.
Stage of growth.
107
What happens when minimum ME and CP intake is not met?
Production is reduced.
108
What should you consider when looking at intake and production?
Class of stock - physiological stage.
Market targets - time, growth
Sheep and pasture management - influence on intake and production
109
Animal management and feed base management are both important factors to consider when matching.....
Feed supply and requirements.
110
Define good feed utilisation.
NSW 20-40% common
VIC 55-60% - very high, doesn't account for seasonality and is risky.
Optimal level is reduced in more seasonal environments due to shorter growing season and less reliable rainfall.
111
What is feed utilisation?
Pasture consumed/pasture produced
112
In which 4 ways can you alter animal requirements to better match your feed supply and demand.
Stocking rate
Enterprise composition
Lambing times
Sale time of stock
113
What is one of the main profit drivers? Discuss it.
Stocking rate.
Low stocking rate - intake is not limited by herbage mass/height but the pasture is not well utilised.
High SR - intake is limited by mass/height, less selection and therefore digestibility, and greater production/cost risks.
114
What is potential stocking rate?
Depends on pasture production and varies with pasture type.
20-25kg DM/ha/mm growing season rainfall
30kg DM/ha/mm growing season rainfall, after 30mm water use.
1.3DSE/ha per 25mm above 250mm rainfall.
When everything is going well, farmers will usually run less than this to decrease risk.
115
What factors should you consider when deciding on sustainable stocking rates?
Minimum 70% ground-cover target (erosion risk).
Grazing to promote pasture persistence and improve its quality - spelling, seedset, avoid overgrazing.
Other feed sources - eg. crops.
Minimum liveweight/CS
Production target
Time of lowest seasonal pasture supply/variability
Cost of supplementary feed
116
Discuss enterprise composition in terms of feed supply and demand.
Increased productivity usually is associated with increased risk.
Need to consider pasture production curve.
Mixed enterprises can be more productive as they allow greater animal selectivity, alternative parasite management, more versatile management and tradeable stock.
117
Discuss lambing time in terms of feed supply and demand.
Dry animals have a flat ME requirement curve.
Reproducing animals have their peak requirements from late pregnancy through to lactation.
Stocking rate lower if peak feed supply doesn't coincide with peak demand (higher supplementation needed).
Difficult to provide optimal pasture conditions for joining, parturition and weaning in a variable environment.
Spring lambing better matches pasture spring growth as long as it isn't a failed spring.
118
What are the advantages and disadvantages of spring lambing compared to winter?
Spring Ad; better captures spring growth in average and better years, and mostly carrying ewes over summer/autumn. Dis; susceptible to failed spring - high feed costs and poor lamb weights.
Winter Ad; less susceptible to failed spring, can sell or keep the lambs depending on the season. Dis; lower kg/ha in average and better years unless you buy in stock, and lamb survival is decreased (environmental).
119
In Southern Australia, when is lambing more profitable?
In late winter and spring compared to winter.
120
Discuss the sale time of stock in terms of feed supply and demand.
Sale of lambs/stock decreases feed demand.
If they weren't sold, would they need to be fed? Costly.
Does retaining surplus in summer/autumn mean that the core flock runs out of pasture in winter?
Does sale age of lambs limit the number of breeding ewes?
121
How can we alter the feedbase?
```
Fertiliser
Species
Crops
Supplements
Fodder conservation
Grazing management
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122
Discuss fertiliser and how it can be used to alter the feedbase.
Nitrogen fertilizers promote growth in vegetative stage, hasten senescence, alters protein:energy ratio and legume content.
Phosphorus fertilisers can improve forage quality and production.
123
How can pasture species be used to alter the feedbase?
Persistence/production/quality - need to understand management requirements and how species fill feed gaps.
Extend the growing season, eg. perennials.
Legumes - increase animal production but have low winter growth.
Value of timing of high quality feed.
124
Describe how crops can be used to alter the feedbase.
Valuable if they allow high growth rates, are of high quality and fill seasonal gaps.
Grazing cereals can be used to provide autumn/winter feed and grain.
Crop stubbles - stems, loose grain, leaves and weeds.
125
Discuss the role of supplements in altering feed base.
Are they being used as supplements or substitutes? Consider the available feed and what is lacking.
Consider the end purpose - eg. compensatory growth.
Energy, protein supplements or intake enhancers.
Consider cost effectiveness.
126
How can fodder conservation be used to alter feedbase?
```
Hay Vs Silage
Is the conservation an annual activity - SR may be too low.
In good years consider the cost
Benefits pasture quality
Fodder needs to focus on quality.
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127
Discuss how grazing management can alter feedbase.
Low SR leads to dominance of erect species and declining pasture quality and wastage (increased DM).
Intense grazing allows dominance by prostrate species and causes slow regrowth.
Grazing should seek to maximise digestible organic matter intake.
The use of grazing systems (cell, rotational, etc) may be used however there is no supporting evidence.
128
What effects does the month of lambing have?
Sets timing for other events.
Impacts profitability - stocking rate, feed costs, sale weights.
Need to consider nutrition, weather at lambing, lamb sale policy and feed base.
129
What should you consider when deciding on the timing of shearing?
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Labour resources/availability
Joining time
Lambing time
Fly risk
Grass-seed risk
Position of break
Weather/shed space
Sheep sale date
Feed availability - particularly in winter
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130
What factors should you consider when crutching?
Shearing time
Fly risk
Lambing time
<3 month crutch to shear interval
131
What is DSS?
Decision support system
Aims to assist advisers, consultants, etc, to help farmers in decision making. Uses a bank of reserach results.
Grazplan incorporates research results into computer DSS.
132
What is Grazplan?
Generalised data over environments and systems.
| Based on numerous biological models that interlink to assist in whole farm decisions.
133
What is Metaccess?
Gives access to the BOM weather database.
| Enables summary and analysis of records to estimate probability of weather events.
134
What is Lambalive?
Enables assessment of the risk of post-natal mortality from chilling.
Uses historical records for the region to calculate a 'chill' index.
Mortality is then predicted from chill index, breed, ewe condition, and % twins.
135
What is Grazfeed?
Assists in assessment of the nutritive value of pasture for specific animals, and the effect of supplementation.
Based on SCA recommendations.
Suitable for any grazing or lotfeeding situation except in arid zones.
Can be applied to pasture, weather, supplement and price, breed, animals, and calculate supplementation levels and target performance.
136
What is SRW?
Standard reference weight
| Weight at mature skeletal size in moderate condition.
137
Compare potential and relative feed intakes.
Potential - depends on SRW, temperature, and lactation.
| Relative - relative availability (mass) and relative ingestibiilty (digestibility).
138
What is Grassgro?
The enterprise model that assesses how weather and soils affect pastoral productivity and profitability.
Can be used to determine optimum SR, produce GM's, predict year to year variability in pasture growth and supply, assess effects of management changes, and simulate grazing.
Takes into account climate, soil, finances, management, breeds, and pastures.
139
What are the highest cost diseases to the sheep industry?
Internal parasites ($369mil), fly-strike ($280mil) and lice ($123mil).
140
Discuss some forms of bio security.
Vendor declaration and sheep health statement.
Purchase from reputable sources.
Sheep-proof fencing
Agreements with neighbours re. strays
Quarantine paddock
Diagnose/deal with problems early.
Contact a vet.
Be aware of trading restrictions.
Ethics - dont knowingly spread the disease.
If it can't be kept out, manage to minimise occurence, production loss and costs.
141
What effect do worms have? How can we manage worms?
Reduce production and increase deaths.
Strategy varies with region (less common in dry climates).
Monitor WEC to determine if drenching is required.
Good nutrition increases resilience.
Manage grazing to keep weaners on cleaner pastures.
Genetics - select sheep with low WEC and dag scores ASBV's.
Rotate drench to reduce resistence.
142
What is flystrike? How can we manage it?
Reduced production and deaths due to wounds in the breech, body, poll, or pizzle regions.
More common in warm, wet conditions.
Predisposing factors; dag, urine, wrinkle, breech, wool, fleecerot, dermatitis, wool colour, long wool, horns, cotted wool.
Manage by crutching, shearing, minimising scouring, genetics (low wrinkle, dag and breech cover), chemicals.
143
What effect do lice have? How can we manage them?
Reduce the wool cut.
Stock movement restrictions
Other things also make sheep itchy - itch mire, grass seeds, dust)
30% of flocks on tablelands are lousy.
Eradicate by doing complete muster, treating all sheep, applying effective chemical, offshear or after shearing cuts heal. Can plunge/cage dip. Increased resistance to backliners.
144
Briefly discuss mineral deficiencies in sheep.
Supplementation is only cost effective if there is a sufficient production response. Seek unbiased vet advice. Can often occur in specific regions and in different seasons on particular pastures.
145
Discuss Ca deficiency in sheep?
Occurs on cereal crops and grain diets. More likely in late pregnant or lactating ewes. Use 1% lime, 1% salt with grain supplements.
146
Briefly discuss Mg deficiency in sheep.
Occurs on lush cereal crops/green grass diets.
Lactating ewes at highest risk.
Prevent with use of Mg supplement.
147
Discuss the issues that grass seeds can cause and how to prevent them.
Can penetrate eyes and skin, cause pain, infection, flystrike and blindness. Result in death, low growth, reduced skin, meat and wool values.
Avoid grazing when seedy, graze lambs/weaners on seed free paddocks, shear or sell before seed period, remove/reduce seedheads (slashing).
148
Are standards enforceable? What about guidelines?
Yes they are.
| Guidelines are not.
149
What are the key welfare issues for sheep?
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Mulesing
Mortality (lambs and adults)
Live export
Stockmanship
Land transport of sheep
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150
What is mulesing?
The removal of skin on the breech to minimise flystrike for life. Usually performed at marking.
Other methods can be used such as selection for sheep with low wrinkle and low breech cover and dag.
151
What is a normal mortality rate for an enterprise in terms of their adult sheep?
2-5% annually
| Need to prevent/manage disease, handle catastrophes (drought, fire, flood, etc), and use good stockmanship.
152
Discuss stockmanship in terms of sheep.
Stockmanship is the handling of animals in a safe and efficient manner. Need knowledge and ability to manage sheep to optimise production and welfare. Occurs through observation, prevention and early action.
Should be efficient work flow and safe, low stress, understand behaviour, take responsibility and manage dogs.
Understanding of feed requirements, risk of flies, behaviour and identifying sick individuals.
