Sheep Management: Flystrike Prevention

Questions and Answers

What is the primary source of protein required for female blowflies before egg laying?

Common sources of protein for female blowflies are carcases, manure, and existing strikes.

At what temperature range does L.cuprina show increased activity?

L.cuprina is most active between 26°C and 38°C.

How does wind speed affect the flight activity of blowflies?

Wind speeds above 9km/h will reduce flight activity, and they do not fly at all when it exceeds 30km/h.

What management strategies can be used to prevent flystrike in sheep?

Management strategies include strategic chemical application, crutching and shearing, and controlling worms and dags. Signup and view all the answers

What is the relationship between dag score and susceptibility to breech strike?

A dag score 4 animal can be up to seven times more susceptible to breech strike than a dag score 1 animal. Signup and view all the answers

Why is assessing worm egg counts (WEC) important in sheep management?

WECs help determine whether worm populations are significant and whether scouring is due to worms or an immune reaction. Signup and view all the answers

How long can shearing and crutching protect sheep from breech strike, and what affects this duration?

Shearing and crutching can provide up to six weeks protection, but this can reduce to three weeks if the sheep are scouring. Signup and view all the answers

What long-term genetic option is suggested for reducing the risk of flystrike?

Breeding for reduced dags and wrinkle is suggested as a long-term genetic option. Signup and view all the answers

What significant event regarding flystrike incidence was recorded at Mount Barker Research Station in September 1978?

The strike incidence was 62% of the total for the year despite extremely low numbers of L.cuprina caught. Signup and view all the answers

Why is prevention of flystrike considered more economical than treatment?

Preventing flystrike avoids the costs and complications associated with treating affected animals. Signup and view all the answers

What are the main types of flystrike observed in sheep?

The main types of flystrike are body strike and breech strike. Signup and view all the answers

How does environmental conditions affect the risk of flystrike?

Environmental conditions influence the prevalence of flystrike by impacting the lifecycle of blowflies and sheep susceptibility. Signup and view all the answers

What is the primary blowfly responsible for initiating flystrike in sheep?

The primary blowfly is the Australian sheep blowfly, known scientifically as Lucilia cuprina. Signup and view all the answers

Describe the lifecycle of the Australian sheep blowfly from egg to larva.

The eggs hatch into larvae in 12-24 hours, which then grow from pinhead size to 10-15mm in about three days. Signup and view all the answers

What is the role of the hairy maggot fly in relation to flystrike?

The hairy maggot fly, Chrysomya rufifacies, invades wounds created by L. cuprina but does not initiate flystrike itself. Signup and view all the answers

Why is it important to reduce the risk of flystrike in sheep?

Reducing flystrike risk improves sheep health, wellbeing, and overall farm productivity. Signup and view all the answers

Why is it important to crutch unmulesed lambs before significant dags form?

Crutching unmulesed lambs before significant dags form is crucial for conducting the operation safely and easily. Signup and view all the answers

What is the primary reason Extinosad® provides limited protection on lambs?

Lambs have less lanolin than adults, leading to reduced binding and retention of the chemical. Signup and view all the answers

What is the recommended tail docking length for lambs?

Lambs should be docked at the third palpable joint or to the tip of the vulva in ewes and to the same length in wethers. Signup and view all the answers

How long do adult Australian sheep blowflies typically live?

Adult Australian sheep blowflies usually live for about two to three weeks. Signup and view all the answers

How does the open hairy nature of lamb fleece affect the breakdown of fly chemicals?

It allows greater exposure to sunlight, resulting in quicker breakdown of the applied chemical. Signup and view all the answers

What factors might influence how susceptible sheep are to flystrike?

Factors influencing susceptibility include sheep health, wool conditions, and environmental conditions. Signup and view all the answers

What method is preferred for crutching excessively dirty unmulesed sheep?

Over the board crutching is suggested for excessively dirty unmulesed sheep. Signup and view all the answers

How does short tail docking affect the incidence of rectal prolapses in sheep?

Docking tails too short increases the incidence of rectal prolapses due to its impact on surrounding muscles. Signup and view all the answers

What physical characteristics identify the Australian sheep blowfly?

The Australian sheep blowfly is copper green in color, about 10 mm long, with reddish eyes. Signup and view all the answers

What precautions should be taken when applying fly chemicals with jetting equipment?

Wear waterproof long pants, steel capped gumboots, long sleeved waterproof gauntlets, and a respirator. Signup and view all the answers

What temperatures do blowfly larvae typically prefer for pupation?

Blowfly larvae typically prefer cooler ground temperatures for pupation, burrowing into the soil at night or early morning. Signup and view all the answers

What is one potential benefit of using the Te Pari Patesco knife for tail docking?

The Te Pari Patesco knife leaves a greater bare area on the tail which may reduce urine stain and dags. Signup and view all the answers

Define 'withholding periods' in the context of chemical application for livestock.

Withholding periods are the time between the application of a chemical and the harvesting of wool or slaughter for meat. Signup and view all the answers

Under what conditions should blowfly prevention chemicals be applied?

Blowfly prevention chemicals should be applied when environmental conditions favor fly development and sheep attract flies. Signup and view all the answers

What negative outcomes can arise from the misuse of chemicals in livestock treatment?

Misuse can lead to resistance development, harmful residues, and adverse side effects on livestock. Signup and view all the answers

What key factors should be considered when choosing a chemical for blowfly treatment?

Factors include whether treatment or prevention is required, withholding period restrictions, and compatibility with pain relief chemicals. Signup and view all the answers

Why might mulesing be unnecessary for some sheep producers?

Mulesing may not be needed in low risk areas or among producers who select for fly and worm resistance. Signup and view all the answers

What is a crucial consideration when applying chemicals to manage flystrike?

It's vital to calculate the correct dosage based on the weight of the heaviest animals in the mob. Signup and view all the answers

How can breeding be utilized to combat breech strike in sheep?

Breeding for resistance involves selecting rams and ewes based on heritable traits associated with breech strike. Signup and view all the answers

What does the term 'wool withholding period' refer to?

The wool withholding period refers to the time required between chemical application and shearing or meat and export slaughter. Signup and view all the answers

What is the role of indicator traits in breeding for breech strike resistance?

Indicator traits are measurable characteristics that can be used to select animals for breeding against breech strike. Signup and view all the answers

Why is pre-lambing crutching beneficial?

Pre-lambing crutching helps remove wool from around the udder, reducing the risk of udder strike and facilitating suckling. Signup and view all the answers

What should be done after using protective equipment for chemical application?

The equipment should be washed, dried, and stored safely, and the operator should change into clean clothes. Signup and view all the answers

Study Notes

Impact of Flystrike on Sheep Enterprises

Flystrike significantly affects profitability through lost productivity and increased costs for treatment and prevention.
Prevention enhances animal welfare, farmer wellbeing, and farm productivity.

Types of Flystrike

Five types of flystrike exist, with body and breech strikes being the most common and impactful.
Risk levels depend on the sheep's susceptibility and environmental conditions.

Risk Prediction

Assessing environmental conditions and sheep susceptibility aids in predicting flystrike risks.
Understanding the Australian blowfly (Lucilia cuprina) life cycle is key to effective prediction.

Biology of the Blowfly

The Australian sheep blowfly causes 90% of flystrikes; it is copper green with reddish eyes and measures about 10mm in length.
It produces smooth-skinned white maggots, and damaged tissue from flystrike attracts secondary flies like Chrysomya rufifacies.

Blowfly Life Cycle

Eggs hatch within 12-24 hours, growing from pinhead size to 10-15mm in three days before dropping to pupate.
Adult blowflies have a lifespan of 2-3 weeks and typically do not travel beyond 3 km from their hatching site.

Environmental Conditions for Flystrike

Flystrike risk increases with temperatures above 15°C, particularly between 26°C and 38°C.
Blowflies are less active in winds above 9 km/h and cease flying over 30 km/h.

Sheep Susceptibility

Sheep susceptibility varies based on environmental conditions, breed type, and management practices.

Flystrike Prevention Strategies

Managing flystrike is more cost-effective than treatment.
Short-term methods include strategic chemical applications, crutching, and shearing; long-term strategies involve genetic selection.

Controlling Worms and Dags

Worm infestations can cause scouring, leading to dag formation, which increases flystrike risks.
Regular worm egg counts (WEC) help monitor worm burdens and control scouring.

Crutching and Shearing

Crutching and shearing provide protection against breech strike; ideally timed before the fly season.
Non-mulesed sheep require careful timing for crutching to maximize protection.

Correct Tail Length

Tail docking should occur at the third palpable joint to reduce staining and dag formation, lowering flystrike risk.
The Te Pari Patesco knife offers a new method for tail docking that may further minimize flystrike risk.

Mulesing

Mulesing may be unnecessary in low-risk areas where sheep are selectively bred for resistance to flystrike and worms.

Strategic Chemical Application

Effective use of flystrike prevention chemicals integrates an understanding of blowfly biology and proper product application.
Chemical choice must consider dosage, withholding periods, and mode of application.

Chemical Safety and Withholding Periods

Safety measures include reading product labels and using appropriate protective gear during application.
Withholding periods must be observed to ensure safety for wool and meat products post-chemical application.

Avoiding Chemical Misuse

Incorrect chemical application can lead to ineffective treatment and resistance development.
Chemicals must only be used as per label instructions to prevent adverse effects.

Genetics in Flystrike Prevention

Breeding for resistance to breech strike offers a sustainable long-term solution.
Selection focuses on traits such as low wrinkle, reduced dags, and adequate breech cover, improving overall resistance potential.

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Description

Explore the significant impact of flystrike on sheep farming profitability. This quiz covers various types of flystrike and their effects on animal health, productivity, and treatment costs. Improve your knowledge on risk reduction strategies for maintaining sheep health and farm efficiency.