Remembering the four pillars of sheep health this summer

After a tough spring on stock through delayed turnout and harsh weather, the focus now must be on giving stock the best possible opportunity to make up for lost gain through both nutrition and healthcare.

While maintaining good -quality swards of leafy grass will go a long way in driving on performance in lambs, controlling parasites (both internal and external), preventing lameness and mineral supplementation, where required, are the key pillars that prop up lamb weight gain.

Fluke and worms are the predominant internal parasites affecting sheep and lambs, with fluke having a lesser effect in the drier summer months.

The traditional approach to controlling worms whereby the focus was on treatment, followed by movement to fresh pasture, is no longer applicable with such practices increasing the rate of resistance developing.

The approach now is to treat when there is a demonstrated need and to use anthelmintics in a manner that protects their efficacy.

Mixed grazing with cattle that will hoover up some of the worms lying on the sward is also beneficial, especially in a set-stocking scenario. Ideally, sheep should be paddock-grazed with land getting a rest period of three to four weeks in between grazings.

The method of controlling the worm burden within sheep has changed over the years, with the aim now being to control rather than eradicate.

Eradicating susceptible worms that can be killed by our current worm drenches can result in resistant worms dominating.

To prevent this from happening, a population of susceptible worms should be maintained in the environment.

To do this, sheep can be turned back out on to the same pasture post drenching to ingest some of these susceptible worms or the stronger lambs in the group showing no signs of ill thrive can be left undrenched.

They will then pass out some of these susceptible worms in their dung which will maintain a population of susceptible worms.

Flystrike is the main issue that sheep farmers face regarding external parasites in the summer months.

The first step to reducing risk of flystrike is the dagging and shearing of ewes/lambs, with wool contaminated with faeces heightening the risk of flystrike occurrence.

The use of pour-ons for control of flystrike and other ectoparasites is extremely popular among farmers, owing to their ease of use, while farmers have also turned back towards plunge dipping in an effort to control the rising number of sheep presenting with sheep scab.

Where scab is identified as being present in flocks, there is no pour-on product currently licensed in Ireland to control or treat scab, with plunge-dipping being the only effective solution.

Farmers in mountainous areas or grazing rougher pasture should opt for products that will also control ticks on sheep

All plunge-dipping products currently licensed in Ireland will control sheep scab.

Secondary coverage for lice, keds and ticks is possible with certain plunge-dipping or pour-on products.

Farmers in mountainous areas or grazing rougher pasture should opt for products that will also control ticks on sheep.

Caution must be exercised regarding the use of products on lambs and sheep destined for the factory, with a large number of plunge-dipping products requiring a 35-day-plus withdrawal period. Where lambs are at a forward store stage, the use of a shorter withdrawal product may be wiser.

Owing to the wet spring and winter just witnessed, anecdotal evidence from farmers indicates that lameness is at a high level in flocks this year.

Scald and foot rot are the two predominant causes of lameness in Irish flocks, with contagious ovine digital dermatitis (CODD) also on the rise.

Scald can be controlled through the regular use of footbathing, with control rather than cure being the aim. Where lambs and ewes are showing physical signs of lameness, scald or other foot issues have been present for some time.

Copper sulphate, zinc sulphate (at a 10% solution) or formalin (at a 3% solution) can all be used to great success.

However, the method of footbathing is as important, if not more so, than the product used.

Sheep should ideally pass through a clean water footbath first to remove any dung or soil from in between the digits of the hoof, before standing in a footbath for upwards of three to five minutes.

Animals should then be placed on a clean concrete surface for 15 minutes after this to allow the product to dry in to the feet.

Footrot cannot be controlled through footbathing. Affected sheep should be isolated and treated with topical (spray-on) antibiotics or injectable antibiotics. The use of a painkiller could also be considered to speed up the process of healing.

Other diseases that can cause lameness in sheep are shelly hoof, toe granuloma or, the above mentioned, CODD.

Identifying the cause of lameness is the first step, and where you are unable to do so you should contact your veterinary surgeon, who will also help draw up a plan to control and treat the disease.

Minerals play an important and complicated role in the thrive of livestock.

The main minerals that are of concern from a sheep point of view are calcium, magnesium, cobalt, copper, iodine and selenium.

However, on most Irish lowland sheep farms, the mineral that is most frequently found lacking in lamb diets is cobalt.

Extreme care should be taken if supplementing with other minerals as excess supplementation of minerals such as copper and selenium can lead to toxicity in sheep, with white-faced breeds of sheep (Texel and Charollais) susceptible to copper toxicity.

The preferred method of mineral supplementation is through drenching or bolusing, as it ensures that each animal receives the correct volume as per their body weight.