Ticks
Cattle tick Paralysis tick
Seasonal trends
- Cattle tick adults most active December through June.
- Paralysis tick most active July through December, adults peaking in spring (normal calving time). 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.
Optimal timing of cattle tick treatment if needed
Early spring or start of wet season
- Start cattle tick treatments early, before tick numbers build.
- Add additional treatments roughly every 3 to 8 weeks (varies depending on the product and application method; follow the product label and take note of withholding periods), or if 20 or more adult ticks >5mm are seen on one side of several animals. The need for treatment will depend on conditions (e.g. fewer ticks in hot, dry years), time of year (start or end of tick season) and the ability to monitor your animals.
- Plunge dip, race spray, or pour-on: 5 treatments with 3 week intervals.
- Injectable: follow the product label: 4 treatments with 4 week intervals OR if long acting, 2 treatments with an 8 week interval.
- ML drench; apply at start of tick season in place of 1 dip or spray.
- End treatments late in the tick season to lower the number of tick eggs released onto the pasture before the dry season (these end of season eggs develop into next season’s ticks).
- Vaccinate all cattle against tick fever at three to nine months of age (often convenient at weaning).
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
Seasonal trends
Louse numbers increase
mid- to late-dry season
Optimal timing of treatment if needed (usually not required)
mid-dry season
Lice numbers increase in the mid- to late-dry season and then decline with increasing feed during the wet season. 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 the middle of the dry season will usually provide effective control.
Worms
Highest WECs
Autumn
Significant worms
Barber’s pole worm (Haemonchus placei)
Nodule worm (Oesophagostomum radiatum)
Small intestinal worms (Cooperia species)
Stomach fluke (Calicophoron calicophorum)
Lungworm (Dictyocaulus viviparus)
Calendar for worm and fluke control
| 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. |
Table 1. Calendar for worm and fluke control.
| Worm control |
May-June |
Oct-Nov |
| Weaners/yearlings |
√ |
(√) Additional treatments in spring and the following autumn as required. WECs useful for young stock. |
| Stomach fluke control |
A single treatment of all weaned cattle in Aug/Sep will usually control stomach fluke in ‘flukey’ areas e.g. swamps, inundated areas, river flood plains. In severe cases an additional treatment may be required in Mar-May based on monitoring and veterinary advice. |
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