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Sheep farmers - TAKE the good lamb prices while available

Lamb prices this year are good and all sheep farmers should draft lambs as they become fit. Farmers should take full advantage of the high lamb prices available at the present time. Anthony Dineen, Teagasc Advisor, also looks at grassland management and blowfly strike prevention methods.

Young lambs, early in the season, can have adequate fat cover for slaughter from as low as 40kg. This will increase to 45kg and higher later in the season.

Kill-out percentages can vary significantly. Lambs that are drafted and killed pre weaning can achieve kill out of up to 50% for well conformed, young, creep-fed lambs early in the season. Whereas lambs killed post weaning later in the season with poorer conformation lambs finished off grass only may only kill out at 42-44%.

When drafting lambs it is important to determine the target carcase weights and draft lambs as these weights are being achieved. It is therefore important to weigh lambs regularly. Assess the fat cover also and draft lambs as they become fit. It is important to monitor lamb performance at this time of the year to avoid animals going overweight. Farmers should also bear in mind the upper carcass weight limits imposed by factories and aim to reduce the number of lambs going overweight and out of spec.

Performance-related issues should also be identified. Lambs should average pre-weaning daily live weight gain for lambs on a grass only diet of 270g and 320g for twin and single lambs respectively.

If performance is below these targets, consider the possible causes: genetics; ewe milk yield; grass yield/quality; mineral deficiency; and possible worm burdens.

Faecal Egg Counts

With regard to worms, Faecal egg counts ( FEC) are especially useful in identifying worm burdens in lambs. Faecal egg counts for stomach worms have risen rapidly during July. When treating lambs for stomach worms ensure you get a faecal egg count done after drenching to ensure that the wormer is still working on your farm. Samples should be taken either seven days (for levamisole-based products) or 14 days (for all other products) after the lambs have been treated. Discuss with your vet or advisor if you find you still have a positive egg count after treatment.

Grassland Management

Many farmers have a lot of grass that is getting stemmy and digestibility is reducing rapidly. Fields that have gone ahead should be taken out for silage.

Don’t move through heavy covers quicker to try and catch up – this will result in poor-quality grass in the next rotation.

Keep on top of grass quality by grazing at the correct sward height and using dry ewes (or by topping down to 4cm) to clean out paddocks after the lambs. Lambs should only be eating short (7-9cm) leafy grass, anything longer is not going to facilitate good weight gain.


Blowfly strike prevention is a task all sheep farmers have to do over the summer months.

Blowfly is an external parasite that commonly appears over the summer months, however, it is not uncommon to hear cases as early as April and as late as November.

Flystrike is a production limiting, costly and sometimes fatal condition in sheep. When it comes to Blowfly strike the aim should really be to prevent it from happening in the first place.

It affects all ages of sheep and is caused when Blowflies lay their eggs on the fleece of a sheep. The flies are attached by soiled areas on the fleece and once the maggots hatch the secrete fluids which attract other flies to lay their eggs on the fleece also.

When it comes to Blowfly strike the aim should really be to prevent it from happening in the first place. There are a number of different options that are available to farmers in this regard.

1) Plunge dipping

For this process to be effective it is important that the dip solution is made up to the correct strength and that fresh dip concentrate is added into the Dip bath periodically (follow manufacturer’s instructions). The length of time that the sheep remain immersed in the dip solution is strongly correlated to the length of time that protection will last for. For that reason sheep should remain in the solution for a minimum of 60 seconds.

2) Insecticidal pour-ons

There are a number of Pyrethroid based pour-ons which offer short term cover (6-8 weeks) from flystirke on the areas where they are applied. These products will also kill maggots if they are applied directly to the larvae.

3) Insect Growth Regulators (IGR’s)

IGR’s work by preventing the maggots from developing for the stage one (non feeding larvae) to stage two larvae (feeding – damage causing larvae). Thus the maggots will hatch from the eggs but subsequently die as they are unable to develop to the stage where they can feed on the sheep. There are a number of different products on the market with varying lengths of cover depending on the concentration of the active ingredient. The duration of cover ranges from; Clikzin (upto 8 weeks), Clik (upto 16 weeks) & Clik Extra (upto 19 weeks). All the Clik products have an added ingredient which results in the active ingredient covering the entire body and binding to the lanolin in the fleece so that protection is not only where the product is applied, but in all the wool covered areas. Critical to using these products is that they are applied BEFORE there is any strike. They products do not kill maggots that have already hatched.

4) Shearing

Shearing will provide protection from maggots due to the inability of the flies to attach eggs to the fleece and for the maggots to have protection in the wool. However this protection is only short lived (a number of weeks).

For season long control the best option is to use a long duration insect growth regulator pour-on. This needs to be applied before sheep are at risk of flystirke and for farmers aiming to sell lambs from the end of June onwards it needs to be applied in mid-May to ensure that the 40 day meat withhold period has elapsed before lambs are ready to draft.

For shorter term control and shorter meat withhold periods use a short acting IGR or Pyrethroid. These will provide 6-8 weeks cover with a 7-8 day meat withhold period.

Where sheep have already been struck or other external parasites also need to be controlled (e.g. ticks, lice etc.) then choose between plunge dipping or a Pyrethroid based Pour – on.

If you enjoyed this article you might also like Ram Factors for the Breeding Season.
The Teagasc Sheep Specialists issue an article on a topic of interest to sheep farmers every second Tuesday here on Teagasc Daily. Find more on Teagasc Sheep here.