Independent UK sheep consultant Dr. Liz Genever is warning of poor conception rates in ewe lambs this autumn if worms are not monitored and managed correctly, after 2020 data revealed the highest yearly worm egg counts were in October and November.

She said that managing worms in ewe lambs in the run-up to breeding is vital to make sure they are at the correct weight and have the best chance of getting in-lamb.

If ewe lambs haven’t reached 65% of their mature body weight by the time they are put to the ram, they are less likely to get in-lamb and if they do, may experience lambing difficulties.

She explained: “It’s not just about their weight, body condition is important too. For most breeds, 65% of their mature weight equates to about 40kg. Condition wise, they need to feel like a body condition score of three, with muscle and fat over the loin.

If they are not at that weight and condition, it is less likely they will be cycling, and it is unlikely they will get in-lamb.

“Ewe lambs need to be closely managed to get to the target weight and condition, with growth rates realistically 150g to 200g/day off grass currently. This is why it is important to manage the general health of these animals well to maximise their growth rates."

Dr. Genever advises all sheep producers to conduct regular faecal egg counts this autumn.

Adding to this, she said: “The general health management of these animals is essential to maintain their growth rates.

"Ewe lambs are still developing immunity to worms and if they go through a period of nutritional stress due to a lack of grass, for example, their immunity may drop. Worms can severely impact lamb growth rates when they are not managed," she concluded.