by Dr Murray Grant
Drenching Programs for Weaner Cattle – Key messages
- Weaner cattle are the most susceptible to worm burdens.
- With good drench and parasite management, the ‘old’ Vetmec Injection (on its own or combined with LEV Pour-On) will still serve you well for years to come.
- Insightful interpretation of one or two worm tests can be extremely beneficial.
In 2023, we did some drench efficacy testing on some weaner heifers and steers based in Gippsland.
This very loyal Chemvet customer has been using Vetmec Antiparasitic Cattle Injection since 2008.
We received some worm test results for the weaner steers and heifers of 200 and 160 egg per gram, respectively. Their last drench was 10 weeks prior, using Vetmec Injection, and approximately 25% of the mob was scouring.
Table 1: Round 1 faecal egg count and larval culture results
| Round 1 Testing | Weaner Steers | Weaner Heifers |
| Strongyle eggs per gram of faeces | 200 | 160 |
| Larval Culture | 28% Ostertagia 72% Cooperia | 45% Ostertagia 55% Cooperia |
Given the weaners had not been drenched long ago, there were some questions around the efficacy of the Vetmec Injection. On my recommendation, these two mobs of weaners were drenched with Vetmec Injection as well as LEV Pour-On (levamisole 200g/L), at the earliest convenience. Another mob was also drenched with a straight doramectin injection (similar to our Vetmec Injection).
A second round of worm testing was conducted 11 days after the weaners were drenched. The faecal egg counts of all three mob samples came back at zero (0) eggs per gram of faeces. This showed that all drenches were 100% effective.
The second round of testing identified that this worm issue was not drench resistance but a drench frequency issue. For this type of property (spring calving with winter rainfall), my overall drench program recommendation for weaners includes:
- Drench at weaning (March)
- Again 6 weeks later (mid-May)
- And again, in July.
This program keeps the cattle clean and prevents larval contamination of pastures. If the second weaning (mid-May) drench were to be skipped, and left until July, the damage is already done and then we’re a step behind getting good control over the worm burden until the end of spring. This program also works where Liver Fluke is present, just use Vetmec F instead of regular Vetmec Injection. Our Liver Fluke article may also be useful for a greater understanding of the Liver Fluke parasite.
For autumn born calves/weaner cattle, bred or introduced to high rainfall areas, we would recommend the following program, which includes an additional drench prior to winter:
- Drench at weaning or when brought onto the property (Jan/Feb)
- Again 6 weeks later (March/April)
- And again 6 weeks later (May/June)
- Winter drench (July)
An alternative to the 3x weaner drench strategy (mentioned above) in cool climates is to use Vetmec LA Long-Acting Injection instead. Vetmec LA will protect against Small Brown Stomach Worm (Ostertagia spp.) for 4 months, saving time, energy, and giving peace of mind that the cattle have no parasites holding them back from their growth potentials during the harsher months. We recommend priming with LEV Pour-On, alongside Vetmec LA injection as a strategy to minimise resistance.
Trace element supplementation
Depending on the location of your property, certain trace elements may be severely deficient. In such cases, the use of trace element and vitamin injections can be important. According to a lot of ruminant nutrition literature, an animal’s growth is only as good as its limiting factor. For example, if stock are deficient in copper or B12, it won’t matter how much feed they’re getting if they’re missing other essential ‘building blocks’ for growth.
Depending on the product, vitamin and trace element treatments can be incorporated at one or more of the following times:
- Marking
- Weaning
- Pre-joining (first calving heifers)
- Pre-calving (first calving heifers)
Even if your cattle are not deficient, they can often benefit from supplementation with vitamin B12 and trace elements (such as selenium, copper and zinc).
With winter and spring calving getting underway, it might be time to start planning your weaner treatments, so that you can be on the front foot with parasite control in your most susceptible stock.
If you’d like to go over anything in this article, or would like a hand in putting together a weaner drenching program, don’t hesitate to give us a call on 1800 243 683 or send an email to admin@chemvet.com.au, and myself or one of our highly trained staff will get back to you.
