Strict worming regime points flock to profit
By Michael Gaisford
A COMPREHENSIVE year-round sheep worming programme is paying dividends on one Sussex farm.
Impressive lamb performance from prolific Cambridge crosses is just one of the results of a meticulous worming programme carried out by Peter Adorian and his son Antony at 110ha (270-acre) Gibbons Mill Farm, The Haven, Billingshurst, West Sussex.
Here, in addition to running a 135-cow dairy herd on just 20ha (50 acres) plus some seasonally rented ground, the Adorians keep a 300-ewe flock of pure Cambridge and Cambridge halfbreds. Some 11ha (27 acres) is used exclusively for sheep, making worm control all the more important.
"Worm control is not an absolute science, and we base what we do here on the latest scientific research and on advice from ministry vets," says Peter Adorian.
Counts of worm eggs on pasture are carried out twice every summer, and form the basis for the drenching programme for ewes and lambs.
Five years ago the wormer of choice was a thiabendazole product, but following ministry tests it was found that worms at the farm had become resistant to it.
So a switch was then made to ivomectin (Oramec) which worked well for the next four years.
This year the Adorians are using morantel citrate (Exhelm).
"We have not changed because of any problems with Oramec, but prefer not to stay too long with the same product," says Mr Adorian.
"We will probably use Exhelm for a couple of years before perhaps changing again," he says.
He reckons that one of his options might be to switch to the Cyanamid wormer moxidectin which has not yet been licensed for use in the UK for sheep, but was trialled with great success on his farm in 1993. One of its claimed advantages is that dosing intervals for lambs during the summer months can be extended beyond that of wormers now available to 35 days.
"But it will also depend on price at the end of the day," says Mr Adorian.
Current wormer costs at the farm work out at £1.70 a ewe a year including treatment of lambs to slaughter weight or until they are sold as shearlings at 16 months old to other farmers.
"When worming sheep the most important thing is to stick to the recommended dose," says Antony Adorian.
"Resistance is built-up by under-dosing, and we always weigh a sample of lambs before drenching them to make sure that the dose they get is accurate."
The basic worming programme for ewes is to drench them three times a year – at winter housing in the first week in January, six to eight weeks after lambing in late March and in the autumn at flushing.
Lambs are also wormed with the ewes at six to eight weeks old, and then every 21 to 25 days until slaughter at 12-20 weeks old. When worm counts are very low, this interval is sometimes extended by a few days.
Lambs are weaned at 16 weeks old and the Cambridge pure-bred lambs to be kept as breeding replacements and the Cambridge half-breds for sale as shearlings are all wormed before they are put onto clean ground.
They are not wormed again until the following spring. Most of the cross-breds are sold privately at about 16 months old. This summer there will be about 100 available for sale.
Peter Adorian says it is difficult to quantify the economic benefits of a good worming programme, but is convinced the programme practised at Gibbons Mill Farm is well worthwhile for his breeding ewes, for the crossbreds sold for breeding as shearlings and for the lambs which go to the Chitty abattoir at Guildford.
Last autumn 293 ewes (116 Cambridge half-breds, 163 pure Cambridge and 14 others) were put to either Charollais or Cambridge rams.
Between them all this spring they produced 690 live lambs (90% of them over an 18-day period in late March/early April with no autumn synchronisation), at an impressive average of 2.35 lambs a ewe put to the tup. Pure-bred Cambridge ewes averaged 2.56 lambs a head.
Grading results for lambs sent to the Chitty abattoir last year at about 35kg liveweight showed that 71% of the Charollais x Cambridge lambs were in the top two grades and received a premium.
"To get the very best grading results we advise farmers who buy our Charollais x Cambridge shearlings for early lamb production to use a terminal sire like a Texel on them," says Mr Adorian.