Hemoata Kopa drenching mixed age ewes on Tautane Station.

As weaning fast approaches it is a good chance to review the animal health challenges from the previous years and make a plan for this season. Each year there are a handful of animal health issues that raise their head on a regular basis and affect lamb growth rates.

Have you checked your drench is working? It seems like a simple question but each year I’m blown away by the number of farmers who have not checked this. It’s really simple and each farm should be doing this at least once a season.

Issues with drench continue to rear their head each autumn. Don’t wait until April when your lambs are wasting away and dying, by then the horse has bolted. Best make a plan to check the drench each summer, simply take 10 faecal samples 7-10 days after drenching, they should all be 0. They don’t have to go into the clinic the same day, simply pop them in the fridge and drop them off the next day. If you change drenches during the season, make sure you check this as well.

Keep to your regular drenching interval, especially during the January-April period. Once lambs get a significant worm burden the damage to their intestines is irreversible. This means that as a result even if you get back on track with your drenching or change to a more effective drench the damage is done and the lamb’s growth potential is compromised.

We see this as slow growth, as the lamb has a reduced ability to absorb nutrients and convert them to muscle.

In summary – be proactive monitoring your drench effectiveness, get a full FECRT done. Make sure this involves single active drenches as well as any combinations you may wish to test.

Testing combinations only, only gives you a fraction of the info you need. Drench resistance is real and it’s everywhere – you don’t want it.

Make sure you have an effective quarantine drench, this needs to be a BZ/Lev combination + either Startect or Zolvix. I’d also strongly recommend that everyone attends a Wormwise workshop, if they haven’t already. Worm management is about so much more that which drench you use.

Pneumonia can be a challenge on many properties and dry summers don’t help with this. Key things to consider include the main culprits, dust and heat. Next you are in the yards working with lambs, get down to the lamb’s height – it can be very dusty. To minimise the incidence of pneumonia – avoid shearing at weaning, avoid moving animals during the middle or heat of the day, set up as system to wet down the yards prior to bringing lambs in and aim to avoid situations where lambs are open mouth breathing.

Trace elements – what do you need? Do you need any? Every farm and every district is different. A simple way to check your needs is to get lamb livers sampled when you send the first line to the works. You only need to sample five, and this will give you information on B12 and Se status and allow you to plan for the months ahead. This can be arranged with your local vet.

Vaccinations – all lambs should be on a 5in1 programme, clostridial deaths are cheap and easy to prevent. The timing of this from docking onwards is necessary if you are feeding high octane crops or new grasses.

Have a look at your kill sheets from last season, is there any mention of inoculation lesions? Inoculation lesions are a common cause of carcase down-gradings. Lesions are more likely to occur if animals are wet when they are vaccinated or dirty needles are used. Get into a habit of changing your needle on a regular basis, eg: every 100 animals. The animals and your hand will thank you.

Other causes for downgrading are using the wrong needle size, therefore damaging the muscle as opposed to the vaccine going under the skin, and vaccinating in the wrong site – try and go as close to the ear as possible.

I encourage everyone to make a lamb sales plan prior to weaning and not get stuck in the trap of holding a lot of lambs into the autumn. Make sure you condition score your ewes at weaning to help guide you in these decisions.

It can be very challenging to put weight on ewes from February onwards, so if your ewes are light at weaning, sell more lambs so that feed can preferentially go into ewes in order to secure next season’s production.

I often see people keep too many lambs for too long and as a result their ewe condition isn’t as good as it should be at mating and scanning isn’t as good as it could be.

  • Rachael Fouhy is a production animal veterinarian at Tararua Veterinary Services.