10. husbandry calendars, precision sheep management and … · 2017. 7. 10. · 10- 1 –...

10- 1 – WOOL412/512 Sheep Production ©2009 The Australian Wool Education Trust licensee for educational activities University of New England

10. Husbandry Calendars, Precision Sheep Management and Benchmarking

Sandy McEachern

Learning Objectives On completion of this topic you should be able to: • define what drives profitability in sheep enterprises • use the key principals that will enable prioritisation and organisation of management

events in order to achieve the most profitable compromise for a farm • describe the role of technologies that allow precision sheep management

Key terms and concepts DSE, Gross Margins, Cost of Production, Net Profit, Labour Unit, Mid-Winter Stocking Rate, Price Received

Introduction to the topic Setting up a profitable husbandry calendar is not a simple task. It involves assessing the resource base of the farm and juggling management events to get the optimum compromise between conflicting needs of pastures, animals, financial resources and labour. There is no one right answer as to what would be the most profitable husbandry calendar, however there are some guiding principals that will allow the manager to set up that calendar within the resources allocated. Other topics within the course will deal with specific issues within the whole system, however the focus of this topic is to provide a framework by which new and existing technologies can be assessed, and then either accepted or rejected in designing the system for the farm in question. In order to do this the manager must be able to prioritise the different components of the production system according to those that have the most influence on profit. These have been identified through benchmarking. Although the content of this topic is heavily influenced by benchmarking and research from winter dominant rainfall regions of Southern Australia where the majority of the national flock resides, once an understanding of the guiding principals has been achieved it should allow students to set up husbandry calendars in other environments.

10.1 Key objectives in designing a husbandry calendar Benchmarking Benchmarking has revealed considerable differences in enterprise performance across Australia. There are two aims of benchmarking. The first is to compare how the enterprise is performing against others, and the second and most important is then to compare how that enterprise performs over time. Table 10.1 shows the five year average gross margin per DSE for different sheep enterprises. The data is taken from Holmes Sackett and Associates benchmarking and is comprised of sheep enterprises across the high rainfall and wheat sheep zones of NSW, Victoria, Tasmania and South Australia. Gross margins are measured on a per DSE basis to allow comparison across different geographic regions, with differing rainfalls.

10 - 2 – WOOL412/512 Sheep Production ©2009 The Australian Wool Education Trust licensee for educational activities University of New England

Dual purpose enterprises are those that specifically aim to maximise both wool and lamb income. They consist mostly of merino ewes joined to British breed rams, where the progeny are sold as slaughter lambs, or as crossbred ewes to prime lamb producers. The wool and lamb enterprises are those that specifically aim to produce the majority of their income from either the wool or the lamb. There are two things that stand out from this table. The first is that dual purpose flocks have a higher gross margin per DSE then either wool or prime lamb flocks, and the second is that there is considerably more variation in gross margins per DSE within an enterprise type than there is between enterprise types. Table 10.1 Average Gross Margins ($/DSE) for the top 20%, average and the bottom 20% of producers in wool, dual purpose and prime lamb enterprises. Source: Holmes Sackett and Associates Benchmarking Data (1997/98 – 2001/02).

Average Gross Margins ($/DSE)

Bottom 20% Average Top 20%

Wool $10.51 $16.49 $23.55

Dual Purpose $12.25 $19.81 $30.87

Prime Lamb $11.64 $16.50 $22.00 From this table it can be stated that it is preferable to be a top 20% producer of any enterprise rather than being an average producer of the best performing enterprise. However the question remains what is the difference between these producers? The profit equation No matter what industry you happen to be in, your profits will be determined by the quantity of what you are producing multiplied by the difference between the price paid for your product and the cost of producing that product as described in the equation below. Profit = Quantity x (Price Received – Cost of Production) Tables 10.2 and 10.3 look at these parts of the profit equation for wool and prime lamb enterprises. The productivity is measured as kilograms per hectare per 100mm of rainfall to allow comparison across geographic regions. For wool enterprises the majority of the difference between the top performers and the average comes from differences in price and cost of production. There is less variation in productivity, however the bottom 20% have significantly lower productivity than the average. For prime lamb enterprises the majority of the difference between the top performers and the average comes from differences in productivity and cost of production. There is less variation in price, however the bottom 20% have significantly lower prices than the average. Table 10.2 The more profitable wool producers have lower cost of production and a higher price received. Source: Holmes Sackett and Associates Benchmarking Data (1997/98 – 2001/02).


Cost of Production ($/kg clean) $7.71 $6.11 $5.28

Price Received ($/kg clean) $6.44 $7.44 $8.88

Productivity (kg/ha/100mm) 3.9 4.5 4.6


Table 10.3 The more profitable prime lamb enterprises have lower cost of production and higher productivity. Source: Holmes Sackett and Associates Benchmarking Data (1997/98 – 2001/02).


Cost of Production $2.37 $1.84 $1.36

Price Received $2.47 $2.56 $2.64

Productivity (kg/ha/100mm) 10.5 12.8 15.5 So there is one key difference between wool and lamb enterprise in what drives profit. In a wool enterprise the manager has the luxury of generating higher income through price by producing wool of a lower fibre diameter. Long term wool prices show finer wool fetches a premium in the market place. In prime lamb enterprises there is no such luxury for achieving premiums in the marketplace. Cost of production is a common point of difference across all sheep enterprises and it is important that this term is understood. Cost of production The cost structure of commercial grazing industries is similar to other industrial type industries in that they are very capital intensive with high fixed costs. These expenses are those that will be incurred in the running of the farm no matter how the manager chooses to operate it.

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Under this financial structure producing more within a fixed resource base will lower cost of production. A key objective therefore of setting up a husbandry calendar is to utilise the resources available to achieve the optimum productivity per hectare. Productivity per hectare is used rather than productivity per head because the limits to productivity per head come before the limits to productivity per hectare. This concept is explained in the Stocking Rate (Morley 1983) reading supplied and it is recommended that students ensure they understand this.

We have seen that there are large differences in productivity per hectare in prime lamb enterprises which will contribute significantly to lowering cost of production. The distinction is not so obvious in wool enterprises because the price received through fibre diameter is also a large determinant of profitability and therefore clouds the effect of productivity. However the goal of producing more of whichever wool quality you are producing should remain the same. The labour and labour related expenses (i.e. vehicles and vehicle running costs) generally account for 25-30% of the total expense of running a sheep enterprise. Therefore a key part of being a low cost producer is having high labour efficiency. The more profitable producers are able to handle considerably more DSEs per unit of labour (Table 10.4) than the average and bottom 20% of producers. Table 10.4 Labour efficiency is a large driver of profitability in sheep enterprises. Source: Holmes Sackett and Associates Benchmarking Data (1997/98 – 2001/02).

Labour Efficiency (DSEs per Labour Unit)

Bottom

20% Average Top 20%

Wool 4313 5505 6028

Dual Purpose 4205 6422 7618

Prime Lamb 4458 6225 7506 (DSEs per labour unit shown are inclusive of all labour involved in shearing. This is not necessarily directly comparable to other benchmarking data).


Relating comparative performance to designing a husbandry calendar If you were to review the different sheep husbandry calendars around Australia you would find almost as many variations as there are enterprises. Even with the one seemingly consistent climate and geographic region you will find a large variation in husbandry calendars. This variation is a direct result of the necessity for compromise when setting up a husbandry calendar in order to satisfy conflicting goals. Examples of conflicting goals include: • what is best for the pasture versus what is best for the sheep • achieving optimum returns per head versus optimum returns per hectare • minimising costs of production versus selling into seasonal highs in the market • the conflicting needs of multiple enterprises (i.e. labour demands for cropping versus

wool). It is not easy to change just one factor of the profit equation without influencing at least one other, so no matter what change you make you must recalculate each of the three parts of the profit equation and work out whether your net position is better. However benchmarking has given us two rules that we can use to guide the design of the husbandry calendar. 1. Aim to increase the per hectare productivity within the existing resource base 2. Aim to increase labour efficiency.

10.2 Designing the husbandry calendar

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A template for a husbandry calendar has been provided as an appendix to this topic. It is suggested that students print a copy of this template and make notes on it as they read through the remainder of the topic. In addition the reading provided titled Planning Sheep Management should be read for explanation and key references to major husbandry calendar events.

Lambing time is the most critical event on a husbandry calendar because of its overarching effects on whole farm profitability. These effects have been modelled (White et. al. 1982) for both wool and prime lamb enterprises. Time of shearing, and other operations such as mulesing are therefore dependent on the lambing time that is chosen. Ewe nutrition The level of ewe nutrition has large effects on weaner growth rates to weaning. Milk production is under control of the condition score of the ewe at the start of lambing, and the pasture availability during lambing (Hough et al. 1986, Hodge 1964). In practice, these factors are determined by stocking rate and time of lambing. Across most geographic regions where sheep are produced in Australia autumn and/or winter provide the least amount of pasture. Therefore, it is very difficult for an autumn or winter lambing ewe to have enough pasture available to meet her nutritional needs without large amounts of supplementary feeding or lowering the stocking rate to a very low level. Both options are unattractive in that they reduce per hectare profitability. Clearly, it is an advantage to lamb when pastures can provide adequate nutrition to ewes through autumn and winter. A system that enables the enhanced feed demands of the ewe during late pregnancy and lactation to occur at the time of the year where there is ample pasture of good quality (mostly spring but in lower rainfall regions it will become late winter) will allow more sheep numbers to be carried through the autumn/winter period where pastures are limiting. More heads means more production per hectare.


Lambing time Whilst the overriding objective in choice of lambing time is to lamb ewes in the spring so that maximum numbers of sheep can be run, it is not quite so simple. The manager needs to consider the product at the end of lambing which is the weaner in a self replacing merino flock or the lamb in a prime lamb flock. For prime lamb production the length of the spring will be insufficient to produce a finished product and therefore the decision on lambing time will be more dependent on the resources available to produce out of season feed. At this stage we can only say that the best option will be the one that allows maximum productivity at the lowest cost. Benchmarking of wool enterprises has shown comprehensively that spring lambing is more profitable than autumn lambing. Unpublished statistical analysis of the Holmes Sackett and Associates benchmarking data of wool flocks has shown that the month of lambing influences profit per DSE by as much as $0.45 per month. However, for survival of the merino weaner, deciding exactly when in the period of good pasture availability lambing should start, the ‘hay off’ time is important. Time of lambing trials by CSIRO across southern Australia in the 1960’s suggested that there should be four months of green feed from the start of lambing till the pastures ‘hay off’. This amount of time is based on allowing the lamb to reach a body weight where it has enough fat reserves to survive under drier pasture conditions (Hodge 1991). This will mean that in the majority of higher rainfall districts lambing will commence from between August and mid September. In the wheat/sheep zones lambing will start from mid July through to late August and in the pastoral zones it may even commence in mid June. As a general rule, in areas where pasture begins to hay off earlier in spring, there will be milder winters and more winter pasture growth, which means that in these areas, lambing can start earlier. The start of lambing will also be influenced by grass seed pickup and the threat of blowfly strike, particularly in the mulesed lamb after lamb marking. However, these issues are relatively minor compared to the availability of pasture for the lambing ewe, and the effect of ewe nutrition on the weaner.

Weather In many districts, August is typically wet and windy. This means the chill factor (more lambs die as the chill factor increases) is often worse than in June and July. This can result in an increase in lamb loss, particularly in twin born lambs due to generally lower birth weights and longer mothering time (Alexander 1964). This needs to be put into perspective; changing lambing time by two months from early August to early October in many districts will alter the lamb mortalities by a total of 7-8%. Even a month later will only make 1-3% difference. Timing lambing for nutritional needs is a far more important consideration than is lamb survival.

Lucerne Where lucerne can be grown and made available to weaners at weaning time, lambing can begin later than the time that would otherwise be considered optimal. This will need to be assessed for your own individual district and circumstances. If lambing starts too early on winter pasture which is unable to support the ewe’s requirements, milk supply and lamb growth to weaning will suffer. If a flock lambs too late and young weaners have to struggle through excessive heat and totally dry pastures, poor growth problems will also be encountered. Whatever date is chosen for the start of lambing, it will always be a compromise.

Joining The date that the rams go into the flock will be 150 days before the desired starting date of lambing. One of the most important ways to avoid problems with weaners is to set up a short lambing span and a concentrated lambing pattern. This helps reduce the ‘tail’ in the weaner mob or in sale lambs as the spread of ages is smaller. The tail is a common source of the management problems and the deaths in the weaners over summer. Some producers may be concerned on missing out on some ‘extra’ lambs. This is not really so.


The average length of the breeding cycle for a ewe is 17 days. To achieve high pregnancy rates, ewes in good condition need no more than 2 cycles exposure to rams. In practice, there is very little to gain from joining ewes for more than 5 weeks during an autumn joining (Figure 10.1) as the vast majority of ewes that will fall pregnant do so in the first two cycles. For a spring or summer joining, 7 weeks is required due to the ‘ram effect’. The ‘ram effect’ results in a two week delay in the cycling activity of ewes when ewes are joined out of their natural breeding season of February to May. Figure 10.1 Most ewes conceive within the first two cycles. Source: How to Successfully

Manage the Merino Weaner. Published by Holmes Sackett and Associates. Benchmarking Data (1997/98 - 2001/02)

Ram management Prior to joining there are some ram management issues that need to be considered. Semen quality is reduced from overheating and it takes six weeks for semen to be produced. It is therefore important to avoid shearing, and aggressive mustering prior to joining. Jet the heads and pizzles of all rams joined in more than three months wool within a week or so of mating. Trim rams feet back to a normal shape. Check the testicles of all rams prior to use and cull any ram where there are significant differences in size between testicles, palpable lumps or bumps, abscesses on the scrotum, and where the combined testicle size is less than 28cm as measured by a scrotal tape. Marking and mulesing Marking and mulesing should occur as soon after lambing finishes as is practical. This will be aided by a tight joining. Weaning Lambs begin to consume pasture from 4 weeks of age, and by 12 weeks of age, pasture forms the majority of their dietary needs (McDowell 1991). Therefore if the lamb is grazing for the majority of its dietary needs by 12 weeks of age then there are several factors which could be limiting the lamb's performance: • Lambs have low immunity to worm burdens and they are likely to be grazing pastures

with high worm larvae contamination. Therefore, worm burdens will quickly reach levels that will have detrimental impacts on production


• There is a tendency for the lamb to follow its mother, and grazes where-ever she has grazed. Therefore, the ewe may be getting the best of the feed and the lamb has to make do with second best if good quality feed is limiting.

Research on wool flocks in a number of different locations indicates that there are substantial advantages from weaning when lambs are 12 weeks old. The results from one experiment at Kybybolite Research Station are presented in Figure 10.2. Most importantly by 4.5 months of age, when in most cases the lamb will be on dry summer pasture, the early weaned lambs were 7 kg heavier than the later weaned lambs. At 28 kg they were well above critical weight. This was not the case for the later weaned lambs. As well, the early weaned lambs cut 0.3 kg more greasy wool at the lamb shearing, and 0.5 kg greasy wool more as a hogget. The ewes from which the lambs were weaned cut 0.1 kg greasy more wool. In practice, if lambs can be given superior conditions in terms of pasture quality and free from infective worm larvae then they are best weaned 13 weeks after lambing commences. This will mean most lambs are approximately 12 weeks old with the youngest lamb 8 weeks of age. A note is required in the husbandry calendar in the previous autumn to begin preparation of a series of weaning paddocks so that weaners have pastures that are as free as possible from infective worm larvae. Merino weaners should be drafted into heavy and light groups at a cut off point of 22-23kg. The heavy weaner group should pose few management problems and should be managed to gain about 1kg per month. The light group must be placed on the best available feed and brought up over the 23kg critical weight as quickly as possible. Below this weight any mild set back can place a weaner sheep’s life at risk.

Figure 10.2 If a better environment can be provided, early weaned lambs grow faster. Source: Geytenbeek et al. (1962).

Train lambs to eat supplements Teaching of grain feeding is a most important safety net in case of some mishap causing weight loss in the weaners. It does not matter what the cause is, if weaners need grain to prevent further weight loss and don’t get it, they will be unable to maintain weight and are at risk of dying. But, how many times have graziers experienced the ultimate in frustration; light weaners needing grain supplements, but none of the mob eating grain when it is offered? This can be avoided by teaching lambs to eat supplements while still on their mothers.


Feeding grain to ewes with adequate pasture may seem to be a waste, but the ewes will eat the grain, and in doing so will teach their lambs how to eat supplements. Four feeds of one kilogram of grain per ewe per feed are all that is needed to train the lambs. If lupins are to be used at any stage, they should be included with the grain fed to the ewes and lambs. However, allow 3 weeks prior to weaning to commence the training when using lupins. The lambs seem to be slower in learning how to eat lupins. Shearing When considering the best time to shear, the decision must be aimed at maximising net returns from the flock. Therefore a range of issues need to be taken into account from the cost of shearing at different times, through the management and production effects to the marketing implications. There is never a perfect shearing time for any flock; there will always be compromises. The important point to remember is to try to avoid compromising the most important factors and don’t worry so much about getting the less important factors right. Major factors • Avoid winter shearing because of the large penalty in winter carrying capacity as a

result of increased feed requirements off-shears (Wheeler et al, 1963). This would apply to all areas except those with very mild winters or where winter feed production is not limiting most years

• Management Program. Issues such as labour availability and cropping/harvesting have a major effect and need to be considered for each enterprise. For example in cropping areas, the choice of shearing time comes down to either a spring shearing or late summer/early autumn. Summer shearings have the advantage of more fine weather and more hours of daylight but this would not be an issue if contractors are used.

Minor factors Factors which are generally of lesser important but still need to be considered include: • The background level of off shears losses tends to be constant all year. However,

Victorian data show that individual large losses have occurred in summer/autumn shearings

• Effect of lamb survival. Shearing pre-lambing has traditionally been considered a method of improving the shelter seeking behaviour of ewes and hence lamb survival

• Experimental work has shown that in fact ewes have to be less than 4 weeks off shears to show any benefit with the greatest benefit being 1-2 weeks off shears at the start of lambing. In most flocks such a short interval between shearing and lambing is neither practical nor desirable

• Timing of sale of surplus sheep. Here there are two factors to consider. The first is to sell sheep in less than 3 months wool at a time of year when sheep sell well. The second factor is to get surplus sheep off as soon as possible, particularly with summer and autumn shearings, to decrease stocking rates as feed availability decreases

• It is also preferable not to join ewes in full wool, especially maidens because the wool on the back and rump of the ewe acts as a contraceptive and physically inhibits the ram from penetrating. Crutching does not resolve the problem.

Provided that it does not incur too much additional labour, it is not a problem to split wether shearing from ewes and it may provide other advantages relating to timing of sales as wethers could be sold off shears at the end of Spring. But do consider the impact this will have on shearing weaners. A split shearing may also impact on lice control. Crutching The overriding principals for where too mark down crutching on the husbandry calendar are that you don’t want to do it more than once in any given year, and you do want to do it as close to shearing as possible (ideally within three months). Crutching twice a year is high cost with no net benefit.


However, based on what shearing date was chosen and when you have decided to lamb this will be made complicated by the desire to have ewes crutched before lambing and/or the prevention of flystrike by removing dags during the fly season. If necessary then it is preferable to combine one crutch with a chemical control application in order to remove the threat of flystrike. Vaccinations Clostridial diseases Two vaccinations 4-6 weeks apart are required for protection over the life of a sheep for its first year. An initial vaccination at lamb marking is required followed by a booster at weaning. The booster dose at weaning will be possible where weaning occurs 13 weeks after the start of lambing, but may not be possible with later weanings. In breeding ewes, a booster dose a month prior to the birth of the first lamb is essential if pulpy kidney has occurred in suckling lambs. The timing of this dose has flexibility. Going more than one month prior to lambing will slightly reduce antibody levels but is unlikely to affect lamb survival. Try to continue the vaccination with other management procedures. Cheesy gland vaccination Recent research has shown a loss of 0.25 kg clean wool when the cheesy gland bacteria first infects a sheep. This usually occurs soon after its second or third shearing. This was accompanied by a 0.1 µ increase in fibre diameter. The catch is to prevent this loss, the whole flock on the farm must be fully protected from the disease through a full 3 in 1 or 6 in 1 vaccination program. Not all sheep will lose wool production. About 70% of the flock will suffer wool loss, once in their life. To achieve adequate protection, the annual booster needs to be given before shearing. For spring shearers, pre-lambing is ideal, and around one of the summer drenches is suitable for autumn shearers. Hoggets also need to receive an annual booster to make the cheesy gland vaccination program worthwhile. Fly control Once temperatures rise above 17°C in spring and moisture is present to activate dermo or fleece rot lesions, then flystrike can become a problem. If sheep are shorn before flies are expected to be a problem, then further control measures are probably not warranted until the autumn. Spring shorn sheep are susceptible to flystrike in autumn. To prevent flystrike in susceptible sheep, a jetting with long acting fly chemical should be considered. This is particularly pertinent for lambs that are to be left unshorn through the late spring and early summer after weaning. Worm control

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Widespread resistance to the major drench groups has created an additional level of complexity to effective worm control programs. The issues relating to worm control are complex and it is beyond the scope of this topic to cover them comprehensively so it is recommended that students read the paper titled Challenges for Worm Control in the Next Decade.

Lambs before about 9-12 months of age, and ewes immediately prior to lambing through lactation lack good immunity to worms. The earlier in the year the lambing time occurs, the quicker ewes are able to contaminate paddocks and worm populations have longer to build up.

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Apart from lambing time, the cornerstone of effective ewe worm control is the summer drenching program with effective drenches in most of southern temperate Australia. The WormKill program will be the basis for worm control in northern NSW and southern Queensland. Copies of these programs are available in the key readings.


However, now the manager has to work out the best compromise between the most effective control of worms for maximum animal production, and the minimum use of the effective drenches available for maximum longevity of their useful life. The key principals behind this being able to implement this strategy are: • Knowing the drench resistance status of your property so that you know which drenches

are effective and which are not. The best way to achieve this is a Faecal Egg Reduction Test, using all of the drench groups including a half dose of Ivermectin to pick up early signs of ML resistance

• At all times you must know how bad the worms are on your pastures and in your sheep. This requires regular Faecal Egg Count of key mobs, and a sufficient understanding of the lifecycle of the worms so that you can interpret those results

• Knowing how to provide safe pastures to sheep through grazing management. Worms can have a devastating effect on weaner profitability. Drenching the lambs at weaning is nearly always warranted because they will be grazing pasture contaminated by the ewes. Most of the lambs will be 9-12 weeks of age and they would have accumulated a worm burden likely to cause losses. Weaner management methods in summer and winter rainfall areas will differ. In winter rainfall regions, a drench at weaning should correspond with the first summer drench for adult sheep and will ensure that weaners enter the summer in a relatively worm-free state. From this point on it is a case of regular monitoring and drenching when necessary. In summer rainfall areas, infective larvae on pasture will represent a big threat in late summer and early autumn. Weaners need to be monitored every three weeks or so with faecal egg counts and an independent advisor consulted as to whether the results warrant the weaners being drenched. For the purposes of a husbandry calendar the manager should note the critical dates for effective control of worms on pastures in that region and then with the use of Faces and a good knowledge of the resistance status to the drench groups available on that farm think through all the possibilities to avoid drenching on those dates without risking a severe breakdown of worm control and losses in animal production.

10.3 Precision sheep management Precision sheep management is a term used to describe the application of technologies to allow the manager to monitor, measure and analyse the production system in order to make decisions that will improve its profitability. In essence it is about harnessing information. To assess the benefit of a new technology the cost of data collection and processing must be weighed against the net benefit that will be accrued to the production system. The system is highlighted so as not to forget that it is a complex mix of resource allocation and compromises between conflicting goals that ultimately makes up the profitability of the enterprise. The costs The most recognisable costs are those relating to data collection and processing which will be a function of the cost of the technology, the labour involved in collection, and the number of times that data can be used. So if a measurement can only be used once then its full cost must be allocated to the benefit of one decision. If it can be used twice then only half the cost goes with the first decision. To be used more than once the data must be recorded in a manner that will allow repetition of the decisions, such as identification of animals with superior traits using ear tags. However this is also an additional cost to the original technology.


The benefits As was mentioned at the start of this section, the benefits to the system are more complex to measure, however the system must be considered at all times along with the benefit from the action taken as a result of the data collection and processing.

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There are numerous examples of ways in which precision sheep management might be utilised in a sheep flock, some of which are described in the reading titled ‘Strategies for lifting productivity in the sheep industry’ (Rowe and Atkins 2004). On farm fibre diameter measurement is one of these. Richards and Atkins (2004) outline sorting sheep on relative meat and wool production.

Figure 10.3 shows the per head benefits accruing to a flock that has implemented fibre diameter testing. This involves testing the individual animal for its fibre diameter at shearing. Scenario 1 is the benefit accruing where the information is used once to class the clip at shearing and then discarded. Scenario 2 shows the benefit where the information is used to class the clip and as a basis for culling decisions, however the data is consequently discarded. In scenario 3 the animals are ear tagged according to micron ranges (no individual identification) and those micron ranges are used in subsequent shearing for clip preparation. Scenario 4 is a repeat of scenario 3, however the animals are individually identified to enable more accurate subsequent clip preparation.

The benefits are very limited for the 23 micron flock because there is little to be gained via premiums for classing that clip according to fibre diameter. The finer the clip, the higher the premium.

Figure 10.3 The annual profit that can be achieved per breeding ewe from the identification scenarios across different micron flocks.

Source: Atkins and Semple (2003).

Scenarios 1 and 2 are the estimated benefit of the technology on its own, whilst scenarios 3 and 4 show the additional benefits accrued using further technology to record and reuse the initial measurements (ear tags and individual animal identification). Scenario 1 is the benefit of making this clip more valuable by classing it and scenario 2 is the benefit of making this clip more valuable and subsequent clips more valuable by removing the higher fibre diameter sheep.

Notice that for fine and medium wool sheep that the majority of the benefit comes from scenario two. That is most of the benefit is from removing animals of inferior quality from the system. However this benefit would be eroded if the removal of the animal meant the farm returns were reduced due to below optimal stocking rate. In simple terms a low performing animal is better than no animal. So the ability to attain these benefits is dependent on the ability to remove that animal from the flock without lowering stocking rate. This will vary according to flock structure and reproductive rate.


Decision support systems In both instances the decision making process is aided by decision support software. For the classing of the clip according to fibre diameter Classer (McKinnon Project) was used, and for the identification and removal of inferior animals Virtual Raceside Classer (NSW DPI) was used. Decision support systems provide useful aids for precision sheep management by modelling expected outcomes from a given scenario. Another example is Grazfeed™ enables the manager to enter an assessment of the pastures available to the animal and make tactical decisions on how to best manage a situation based on estimated animal performance on that pasture. Improving the productivity of the individuals within the system If the sheep enterprise does have the ability to cull to a level where removal of inferior performing animals will have no detrimental impact on stocking rate then it is important to remember that most of the benefit will come from the higher average performance of the remaining animals during their lifetime. If the bottom 10% of performers on fleece value were culled the average of the remaining mob would be higher and therefore the returns better (on the provision that the mob does not have to carry the cost of a reduced stocking rate). The benefit accruing from the progeny of the retained animals being more productive is much smaller than the lifetime gain. Using a model developed by CSIRO (run by SELECT Breeding Service of CSIRO, Armidale) the benefits of selection based on fibre diameter have been analysed for a fine wool flock using median prices from 1996-2000. Figure 10.4 shows the cumulative cash position (cumulative return per head minus the initial cost of measurement) after testing a flock of fine wool ewe hoggets, allowing $2 per head for the cost of testing. Note that by year five, the majority of the returns ($8.60) have been received and after year five additional gains (via the progeny) take a long time and are relatively small. In fact 2/3 of the total benefits are from the selection of the ewes. Figure 10.4 Most of the benefit for selection based on fibre diameter is achieved during

the lifetime of the ewe rather than from subsequent generations of progeny. Source: McEachern (2006).

So the contribution to genetic gain from ewe selection is going to be much less in a commercial flock than through ram selection. This is because you will be limited in the number of ewes that can be culled out in this manner and therefore will be limited in the amount of selection pressure you can apply. The rams you buy are still the main drivers of genetic improvement of the flock.


Readings !

The following readings are available on CD:

1. Bell, K. 2003, ‘Challenges for Worm Control in the Next Decade’, Merino Selection Demonstration Flocks Newsletter Number 7, March 2003.

2. Lean, G. ‘Time of Shearing’, in How to Successfully Mange the Merino Weaner. AgInsights 4.0 Holmes Sackett and Associates. pp. 23-25.

3. Love, S. and Lloyd, J. 1999, DrenchPlan 2000. AgNote DAI/88 First Edition, NSW Dept. of Agriculture.

4. Love, S. and Biddle, A. 2000, WormKill 2000. AgNote DAI/118 First Edition, NSW Dept. of Agriculture.

5. Morley, F.H.W. 1983, ‘Stocking Rates’, Refresher Course for Veterinarians, Proceedings No. 67. pp. 93.

6. Morley, F.H.W. 1994, Planning Sheep Management. Merinos, Money and Management, Post Graduate Committee in Veterinary Science, University of Sydney, pp. 83.

7. Rowe, J.B. and Atkins, K.D. 2004, Strategies for lifting productivity in the sheep industry. Cooperative Research Centre for the Australian Sheep Industry. Unpublished.

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Summary The timing of events on a husbandry calendar are by and large at the discretion of the manager, and therefore the manager is required to have a comprehensive understanding of what drives profit for the business. Maximising the total productivity of the property is more important than maximising the productivity of the individual animal and therefore animal performance will nearly always be compromised in order to achieve maximum benefits for the business.

Because of its impact on utilisation of pastures, choice of lambing time is the most important event in the husbandry calendar. All other events should be added to give the best compromise around the decision on lambing date


References Alexander, G. 1964, ‘Lamb Survival: Physiological Considerations’, Proceedings of the Australian Society of Animal Production, vol. 5, pp. 113. Atkins, K. and Semple, S. 2003, ‘Using Fibre Measurements for Clip Preparation and Selection in Commercial Merino Flocks’, Wool Technology and Sheep Breeding, vol. 51(2), pp. 127-129. Bell, K. 2003, ‘Challenges for Worm Control in the Next Decade’, Merino Selection Demonstration Flocks Newsletter, Number 7, March 2003. Geytenbeek, E., Goode, J.R., and Schuller, W.J. 1962, ‘Age at weaning – its effect on growth and production of young merino sheep’, Proceedings of the Australian Society of Animal Production, vol. 4, pp. 130-134. Hodge, R.W. 1964, ‘Milk and Pasture in Growth of Lambs’, Proceedings of the Australian Society of Animal Production, vol. 5, pp. 145-148. Hodge, R.W. 1991, ‘Weaner Management’, in Australian Sheep and Wool Handbook, (Ed. Cottle, D.), Inkata Press. pp 164-171. Holmes Sackett and Associates Pty Ltd (HSA). Benchmarking Data 1008/98 - 2001/02. Wagga Wagga, N.S.W. Holmes Sackett and Associates Pty Ltd (HAS). How to successfully manage the Merino weaner. Holmes Sackett Associates, Wagga Wagga, N.S.W. Hough, G.M., Williams, A.J., Annison, E.F., Murison, R.D. and McDowell, G.H. 1986, in Proceedings of the Australian Society of Animal Production, vol. 16, pp. 416. Lean, G. ‘Time of Shearing. How to Successfully Manage the Merino Weaner’, AgInsights 4.0. Holmes Sackett and Associates, pp. 23. McDowell, G.H. 1991, ‘Lactation and Lamb Growth’, in Australian Sheep and Wool Handbook, (Ed. Cottle, D.), Inkata Press. pp 144-161. Morley, F.H.W. 1983, ‘Stocking Rates’, Refresher Course for Veterinarians. Proceedings No. 67. pp. 93. Morley, F.H.W. 1994, ‘Planning Sheep Management’, Merinos, Money and Management. Post Graduate Committee in Veterinary Science, University of Sydney, pp. 83. NSW Dept. of Agriculture 1999, DrenchPlan 2000, AgNote DAI/88 First Edition. NSW Dept. of Agriculture 2000, WormKill 2000. AgNote DAI/118 First Edition. Richards, J.S. and Atkins, K.D. 2004, ‘Simultaneous assortment of animals for meat and wool production in merino flocks’, Wool Technology and Sheep Breeding, vol. 52(3), pp. 193-201. Rowe, J.B. and Atkins, K.D. 2004, Strategies for lifting productivity in the sheep industry, Cooperative Research Centre for the Australian Sheep Industry. Unpublished. White, D.H., Bowman, P.J., and Morley, F.H.W. 1982, ‘Choice of Date of Lambing and Stocking Rate for Merino Wool-Producing Flocks’, Proceedings of the Australian Society of Animal Production, vol. 14, pp. 38. White, D.H., Bowman, P.J. and Morley, F.H.W. 1982, ‘Choice of Date of Lambing and Stocking Rate for Prime Lamb Producers’, Proceedings of the Australian Society of Animal Production, vol. 14, pp. 41.

Wheeler, J.L., Reardon, T.F., and Lambourne, L.J. 1963, ‘Effect of pasture availability and shearing stress on herbage intake of grazing sheep’, Australian Journal of Agricultural Research, vol. 14, pp. 364.


Glossary of terms Cost Of Production the total expenses incurred by the enterprise divided by the total

kgs or tonnes produced. If the cost of production is the same as the price received, the return on assets generated by the business will be zero

DSE dry sheep equivalent equates to a shorn, fasted, 45kg wether. All classes of cattle and sheep can be converted into multiples of the DSE unit. Refer to Appendix II

Labour Unit the labour input of one individual for 48 weeks at 40 hours per week. Casual and permanent labour is expressed as a fraction

Mid-Winter Stocking Rate

the number of DSEs being run per hectare on July 1

Price Received the gross price received per tonne or per kilogram liveweight for product

Gross Margin this is the income generated by the enterprise after direct expenses have been deducted

Net Profit this is the profit of the enterprise after all direct and overhead expenses have been deducted, but before interest costs. It is an accounting profit and takes into consideration non cash expenses such as depreciation, but excludes capital spending

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