Shearing

Key Recommendations
  • Avoid joining ewes in full wool due to the negative effect on conception rate
  • Joining ewes in short wool has shown to increase conception rates
  • Avoid joining ewes within two weeks of shearing as shearing can disrupt cycling activity for up to two weeks
  • Crutch 3 months prior to shearing to reduce potential stained fibre contamination
  • Undertake general health check of animals and remove any unwanted animals from the flock
  • Record an average body condition for each mob
  • Check for any signs of lice
Shearing Twice a Year

As new wool markets emerge and producers continue to breed more robust and productive sheep, shearing every 6 or 8 months is an increasing practice for farmers to consider. There are a number of factors to weigh up and is not suited for every operation.

This shift requires economic analysis and careful planning. It’s important to plan the production year, with a calendar of shearing, mating and lambing dates, and ensure it suits seasonal conditions.

Factors to consider include: 

  • Your average wool length growth in 6 months
    • targeted markets are looking for wool length >60mm
  • Identify target wool market
    • know the important characteristics that influence price of wool at sale
    • identify the factors influencing demand and how they affect wool price
  • availability of shearers
  • shearing in the heat of summer
  • avoid a tender spot in the wool in the middle of the staple

Benefits of shearing more often (every 6 or 8 months)

  • Improved wool yield and quality
  • Improved tensile strength (particularly seen with 6 month shearing)
  • Minimise tender wool being in the middle of the staple (particularly seen with 6 month shearing)
  • Improved cash flow in comparison to twelve month shearing
  • Crutching is eliminated
  • Easier management of flystrike, which reduces chemical use for fly control.
  • Improved management of lice by having two opportunities throughout the year to treat off shears and can reduce chemical use for lice control
  • Ability to join post shearing allowing for a positive shift in energy balance which increases percentage of ewes scanned in lamb
  • Ability to shear pre-lambing which will increase lamb survival and birth weights
  • Greater control and management of ewe body condition.
    • An increase of 1 CS will result in an increased 0.8 kg CFW
    • Lamb survival increases with increased ewe condition score at lambing
    • Ewe in higher condition score are less susceptible and have a higher threshold to internal parasites.  This is particularly important to ewes that lamb in spring and lactate over summer in high rain fall areas
    • Poor ewe condition score and nutrition at leading up to and during lambing has a detrimental effect ewe maternal behaviour and lamb survival
    • Sheep with low weight gains and condition score due to poor nutrition or other stress events may be more susceptible to lice and develop heavier infestations (James et al. 1998).

The risks associated with shearing more regularly include:

  • Allocating a time for a second shearing into your production calendar that doesn’t compromise wool or lamb production capacity
  • Not clashing with other major on farm production events i.e harvest
  • Increased labour costs at shearing
  • Shearing in hot summer months or in the middle of winter.
  • Unavailability of contract shearers
  • The costs of shearing
Influence on Lamb Surviability

Shearing within the last 6 weeks of gestation has positive benefit on lamb survivability. Though shearing this close to lambing does increase the risk of metabolic diseases such as pregnancy toxaemia. Ewes are more likely to seek shelter after being shorn pre-lambing. However, for this to take effect shearing must occur within 4 weeks of lambing (table – planning for profit: Australian wool innovation, 2003).

Effects of time of shearing (weeks before lambing) on shearing during lambing: 

Weeks before lambing starts

Ewes sheltering 4 weeks after the start of lambing (%)

1

90%

2

82%

4

86%

8

26%

 Shearing 4 to 6 weeks prior to lambing benefits include:

  • Increased appetite which leads to increased milking production and birth weight. This is assuming that all the ewes’ nutritional requirements are met
  • Retain more ewes in your breeding flock as they are more likely to consecutively get in lamb. For example: Ewes in close to full wool, heavy in lamb in winter or early spring are more likely to becoming cast and often fail to recover
  • Easier access to udder for suckling lambs
  • Coincides with the point of minimum fibre diameter which generally occurs at the end of pregnancy, this will ensure that the staple ‘break’ will occur closer to the end of the fibre and will have a minimise impact on wool value
  • Avoiding the pregnancy effect of wool yield as fibre production declines by around 40% over the period of pregnancy and lactation. The effect is greatest in the third trimester of pregnancy (last 7 weeks) as ewe nutrient demand is at its greatest due to rapid foetal growth. Studies in merino ewes (Handsford and Kennedy, 1988) show reductions in wool growth from between 20 – 40%, which constitutes between 4 – 13% of overall fleece weight).

Potential risks from pre-lambing shearing

  • Inducing metabolic disorders such as pregnancy toxaemia
  • Up to a 40% increase in energy requirements for up to 6 weeks after shearing which can lead to ewes consuming a lot more feed during pregnancy, making it difficult to achieve FOO targets at the start of lambing
  • Exposure of wet weather could result in increased mortality of ewes. Ewes in good condition (CS >3) are more able to withstand the effects of cold weather after shearing.
Importance of Timing

There is never a perfect time to shear, though when making a decision on a shearing date it is important not to compromise the most important factors within your in your business. Within any sheep enterprise finding an appropriate time to shear ranks second behind lambing time as the most critical date in the sheep production system.

Key important factors to consider:

  • Avoid shearing in winter because of large penalty in winter carrying capacity as a result of increased feed requirements off-shears (wheeler et al., 1963)
    Sheep are most at risk of death due to exposure for the first 2 weeks post shearing, though losses can occur for up to 4 weeks in unfavourable cold, wet and windy conditions. This risk factor must be taken into account when deciding when to shear.
  • When evaluating the options, a distinction between annual and perennial pasture systems must be made given the difference between the two in pasture dynamics and time of seed set.
  • When shearing in spring consider the following factors:
    • Lower Vegetable matter and seed penetration (Warr and Thomspon 1976)
    • Minimise fly strike during high risk periods over summer
    • Spring shearing followed by a dry autumn will increase the risk of the position of break to being closer to middle of the staple which leads to an increased likelihood tender wool.

References:

Sackett, D., Holmes, P., Abbott, K., Jephcott, S. and Barber, M. (2006). Assessing the economic cost of endemic disease on the profitability of Australian beef cattle and sheep producers. Project AHW.087 Report, Meat and Livestock Australia, North Sydney, 119 pp.

James, P.J., Horton, B.J., Campbell, N.J., Evans, D.E., Winkleman, J. and McPhie, R. (2011). Population dynamics and production effects of sheep lice (Bovicola ovis Schrank) in extensively grazed flocks. Animal Production Science 51, 753-762

Kettle, P.R. and Pearce, D.M. (1974). Effects of the sheep body louse Damalinia ovis on host weight gain and fleece value. New Zealand Journal of Experimental Agriculture 2, 219-221

Wilkinson, F.C., de Chaneet, G.C. and Beetson, B.R. (1982). Growth of populations of lice, Damalinia ovis, on sheep and their effects on production and processing performance of wool. Veterinary Parasitology 9, 243-25

Niven, D.R. and Pritchard, D.A. (1985). Effects of control of the sheep body louse (Damalinia ovis) on wool production and quality. Australian Journal of Experimental Agriculture 25, 27-31.

Hansford, K.A and Kennedy, J.P 1988, ‘Relationship between the rate of change in fibre diameter and staple strength’ Proceedings of the Australian Society of Animal production, vol. 17, pp. 415 – 419.