North Coast NSW

While you may be researching or planning a program for a specific parasite that is a problem for your property, it pays to be aware of what other parasite risks may be approaching and make an integrated plan.

Programs for the key parasites, ticks, buffalo fly, lice, worms and fluke can be opened below. The recommendations are generic and therefore need to be customised to the needs of individual producers and delivered by those with knowledge in the  field.

Be aware that chemical resistance can develop in both targeted and non-targeted parasites.

Use of chemicals to control one type of parasite can also unintentionally select for resistance in a different group of parasites. It is important to read the label to determine which parasites will be controlled. Resistance is a significant issue in ticks, buffalo flies and cattle worms. When choosing a chemical to control one of these parasites, consider the possible side effects of increasing selection for resistance to the others.

Strategies for delaying the emergence of chemical resistance include:

  • Where possible include non-chemical control strategies to reduce reliance on chemical treatments.
  • Avoid frequent use of the same chemical or chemicals within the same chemical group.
  • Don’t under-dose products as this allows the more tolerant pests in a population to survive. Common causes of under-dosing include under-estimating the weight of animals being treated, poor application technique, and mis-calibrated application equipment.
  • Use chemicals according to the product label.

Read more:

Ticks

Cattle tick is not routinely a problem in this region but outbreaks can and do happen, most often following cattle introductions from other tick-endemic areas.

Problem ticks

  • Paralysis tick and bush tick occur in this region peaking in spring and summer.
  • Routine control measures for bush tick are generally not warranted.
  • Young calves are particularly susceptible to paralysis tick toxin so if your property is in a paralysis tick area, consider treatment before paralysis ticks can inject a lethal dose of toxin.

Flies

Buffalo flies

  • Treat if buffalo flies are above threshold numbers before Christmas, or after ear tags have expired (apply an OP spray or a pour-on from a different chemical group to that of tags). Industry threshold numbers are:

Beef animals. 200 flies

Dairy animals. 30 flies

  • Apply insecticidal tags when flies are above economic thresholds in January.
  • Remove tags when they expire (Check label; 16 weeks for most tags) to avoid selecting for resistance.
  • Use ear tags from different chemical groups in successive years (OP, SP, ML).
  • Consider using buffalo fly traps or backrubbers.

Lice

Lice on cattle are generally not an economic problem. Only treat when heavily infested as indicated by rubbing on fences or structures.

Seasonal trends

Louse numbers increase

late autumn  early spring

Optimal timing of treatment if needed (heavy infestation)

late autumn

Louse numbers increase from late autumn through to early spring and then decline with increasing temperatures in spring and summer. Heavy infestations are usually seen in cattle in poor body condition. In most cases the lice are a consequence, and not the cause, of poor nutritional conditions. Where lice are an on-going problem a single treatment in late autumn will usually provide effective control.

Worms

Highest WECs

??  Winter

Significant worms

??  Barber’s pole worm (Haemonchus placei)

??  Small brown stomach worm (Ostertagia ostertagi)

??  Small intestinal worms (Cooperia species)

??  Liver fluke

Other worms

??  Nodule worm (Oesophagostomum radiatum)

??  Stomach hair worm (Trichostrongylus axei)

??  Stomach fluke (Calicophoron calicophorum)

Calendar for worm and fluke control

Table 1. Calendar for worm and fluke control in spring calving herds.

Age group

Mar-May

Jul

Sep

Dec

Weaners

Weaning

()

Yearlings/First calvers

() Pre-calving

 

()

2nd calvers

 

() Pre-calving

 

 

Adult cows

Adult cows usually develop a strong immunity to roundworms so mob-scale drenching should not be required – individual cows showing reduced weight gains or signs of internal parasitism (diarrhoea, low body condition score, ill-thrift or high WEC) should be treated.

Bulls

 

 

 

√ Pre-joining

Liver Fluke control

All weaned cattle

Fi

 

F

(Fi)

Stomach fluke control

A single treatment of all weaned cattle in Sep will usually control stomach fluke in ‘flukey’ areas e.g. swamps, inundated areas, river flood plains. However, in some cases an additional treatment may be required in Mar-May based on monitoring and veterinary advice.

KEY

Strategic worm treatment given each year

()

Not a routine treatment. Indicators for treatment include scouring, sudden loss of condition and a condition score of 2 or less, especially if feed availability is less than 1,000kg DM/ha. Treatment will be more effective if combined with a change to ‘low-risk’ pastures, especially for young stock.

Fi

Both adult and immature fluke present – select a drench that kills all fluke stages

(Fi)

Adult and immature fluke present. This drench may not be needed on properties with a low fluke risk.

F

Only adult fluke present. Use a drench other than triclabendazole to help slow the development of resistance.