Dipping management

It is peak season for dipping, with some plunge-dipping contractors two to four weeks behind work due to a prolonged shearing season.

With greater scrutiny around the disposal of spent dipping product, it is important to ensure you are compliant with the regulations.

Spent sheep dip can only be spread during the spreading season for slurry, which closes on 8 October.

It is advised to dilute spent dip at a ratio of at least one part dip to three parts slurry/water and to land-spread at a rate not exceeding 5,000l/ha of spent dip or equivalent to 20,000l/ha of diluted dip.

The success of dipping will be influenced by adopting best-practice management techniques. The dipping bath should be clean prior to starting and filled with clean water.

An accurate measurement is essential for establishing dilution rates.

Sheep should be rested for a couple of hours before entering the tub and ideally fasted to reduce faecal contamination.

Sheep should remain in the solution for at least 60 seconds and be fully immersed at least once during this period.

When mixing the dip no other chemicals such as fleece colourants should be added to the mixture as these can have a detrimental effect on the quality of dipping.

Sheep should remain in the draining pen until they have visibly stopped dripping and only be released to a grazing area where there is no risk of runoff coming in contact with watercourses.

Manufacturers recommend to top up after at least every 36 sheep and follow dilution ratios to ensure the correct strength is maintained.

The batch should be fully replenished after it reaches one sheep for every 2l of capacity, ie, for a 1,000l batch it should be fully replenished after 500 sheep.

Sheep should never be dipped in solution which has been left overnight, and veterinary advice warns against treating sheep with a levamisole product for 14 days either side of dipping.

Hill flock breeding strategies

The level of productivity in a hill sheep flock will have a direct influence on the options available for crossbreeding.

The table above details the potential level of crossbreeding possible based on varying levels of output.

The Teagasc guidelines are based on a hill flock with a replacement rate in the region of 24% and allowing for 10% of ewe lambs bred to be deemed unsuitable.

Output will be directly influenced by ewe body condition and liveweight. Teagasc research shows a strong association between the liveweight of Scottish Blackface ewes at mating and subsequent litter size.

For example, increasing the BCS from 2 to 3 has the potential to increase lambing percentage by 13.5%. This is partly influenced by higher conception rates.

The focus of the breeding policy for ewes should remain focused on breeding a type of ewe that can perform satisfactorily in the environment in which they are run.