01/11/2024

The process of weaning a lamb off its mother is one of the most stressful events in a sheep’s life. We take the lamb off its mother and then place it in a paddock with other young, stressed lambs and expect them to continue to gain weight. 

To ensure that the lambs overcome this stress quickly and continue to grow, we must provide them with the best start possible by effectively controlling internal parasites, vaccinating, and feeding them well. 

At weaning, lambs have only been grazing pasture for a short period of time and have had limited exposure to internal parasites as long as a low-risk lambing paddock was prepared for the ewes. This combined with low immunity due to their age makes lambs extremely susceptible to becoming infected with internal parasites which will have a detrimental impact on their growth rate and could also lead to death. To combat this, drenches have been a mainstay in the control of internal parasites and the weaning drench is one of the most important. 

If a low worm risk paddock has not been prepared for the ewes and they have lambed on short pasture with a high level of parasite contamination, then a drench prior to weaning may be required. Perform a faecal egg count (FEC) on the ewes and lambs to determine if a drench is required prior to weaning. 

Drench resistance in Australia is very common and using an ineffective drench at weaning could have an impact on the profitability of the farm and welfare of the lambs. Selecting the right drench is vital. However, before selecting a drench, several things must be taken into consideration.

1. Do you require a drench with a short withhold period (WHP) and export slaughter interval (ESI)?
2. Use the most effective drench. A drench that has efficacy above 95% should be used.
3. Using combination drenches is recommended due to their ability to obtain higher efficacy than single active drenches and slow down the development of resistance.
4. The weaning drench should be different to the pre-lambing drench that was given to the ewes.

Tapeworm in lambs

Tapeworm in lambs can be very common and is easily seen in the faeces of the lambs as the tapeworm segments look like small grains of rice. Even though tapeworms can grow to over a metre long in the small intestine, there is no evidence that this will affect the health of the lambs. If a drench that will effectively control tapeworm is desired, it should contain the active ingredient Praziquantel as it is the only effective drug that will kill the head and segments of the tapeworm. Article discussing tapeworm and control in sheep is located on the Wormboss site here.

With many producers not knowing the resistance status of the worms on their farms, possible options are shown in Table 1:

Table 1: List of possible weaning drenches

*Registered trademark of Virbac  ** As per label

*** Do not mix products in the same syringe prior to administration.

Making sure the drench has worked

After the weaning drench has been given, a FEC should be performed 14 days later to confirm that the worms have been removed. Ideally, if looking to obtain a percentage efficacy of the weaning dose, a FEC should also be performed on the lambs on the day of treatment. Alternatively, see what drenches are working in your local area by visiting the Tridectin Drench Efficacy Portal. 

Weaning is also the ideal time for the lambs to receive their second 6 in 1 vaccine that will protect them for the next twelve months provided they received their first vaccination at lamb marking, 4-6 weeks prior to weaning. 

For more information or assistance in designing your sustainable worm management program contact your local Virbac Area Sales Manager.

*DISCLAIMER:

The information provided in this article is intended as a guide only. Information contained in this article has been provided by the manufacturer/ You should not rely on the information in this article, and it should not be considered advice. You should seek professional advice regarding relevant factors specific to your situation. This article does not take into account variable conditions that may impact performance. Always read and follow label directions before using any product in this article. To the maximum extent permitted by law, Nutrien Ag Solutions Limited and its related associated entities will not be liable for any loss or damage suffered by any person arising out of any reliance on any information contained in this article.