Stay healthy this spring and summer

Protecting against orf

Orf infections can hit at any time but are most common in young lambs and their ewes in springtime and in older lambs in late summer. Clinical signs of the disease occur where the skin becomes damaged; for example, rough grazing such as thistles, briars or damage from sharp edges on feed/water troughs.

Characteristic signs are lesions/scabs on the mouth, nostrils and lips of lambs, lesions on the ewe’s teats or lesions on the feet of animals. The disease can cause issues with lambs suckling or can lead to sore teats and udders of the ewe. As a result, ewes may not stand for lambs to suckle, leading to starvation or mastitis.

Orf is a viral disease and, as such, there is no reliable or straightforward treatment. Injectable antibiotics can be used to prevent secondary bacterial infections from occurring. Lambs should be fed artifically if needed and ewes should be monitored closely to prevent against mastitis and ensure that lambs are suckling adequately.

Scabivax is the only vaccine available to protect the flock from disease. Never use the vaccine on farms where orf has not previously been a problem as this will only serve to introduce orf to the flock.

The vaccine is a scratch vaccine. It is applied behind the elbow or axilla (area between the top of the foreleg and chest wall). Recommendations include not vaccinating in wet weather. It is advisable to check animals a week later to ensure that the vaccine has taken.

As is the case with all live vaccines, great care is needed when handling and administering (human health) and manufacturers’ recommendations should always be followed.

Clostridial disease

Recommendations on vaccinating for clostridial diseases have varied slightly. Ewes vaccinated pre-lambing will transfer antibodies to their lambs via colostrum. Under normal management conditions, these antibodies will provide protection against clostridial diseases until eight to 10 weeks of age. However, protection against pasteurella and pneumonia will only last until about three weeks of age.

Flockowners need to weigh up if they wish to vaccinate at three weeks of age or wait until lambs reach 10 weeks.

Vaccination should not take placen within the first three weeks of a lamb’s life as it will interfere with antibody uptake. There are a number of products on the market for vaccinating against clostridial diseases.

Different products provide variable levels of protection.Some provide protection against pasteurella and pneumonia while others provide protection to a narrow range of diseases for lambs destined for slaughter.

Heptavac, Covexin 8, Covexin 10, Tribovax 10 and Heptavac P Plus provide protection for sheep destined for long-term breeding while Ovipac p is aimed at fattening lambs.

For full immunity, two shots should be administered about four to six weeks apart.

Fluke

Weather is improving but fluke may still be a concern in outwintered flocks. Advice from the Department Fluke Advisory team is to treat outwintered ewes in January and again in April.

Nematodirus

Nematodirus affects lambs aged four to 12 weeks of age and can also be a problem with young calves. Peak hatching of eggs usually takes place in early to mid-April or even earlier in coastal areas. There has been no announcement yet from the Department or AFBI on predicted peak hatching dates this year.

Clinical signs include lambs suffering from profuse diarrhoea and wasting away. Mortality rates can be high if left untreated.

The advice usually given is to dose in early to mid-May with a suitable anthelmintic. This is advised to prevent against problems at a later stage and also to lower pasture contamination for the following year.

The incidence of disease can be reduced by grazing pastures that lambs did not graze in the previous spring, but this is not always an option.

It is also recommended to use a narrow spectrum wormer that will target adult worms. This is advised to guard against the development of anthelmintic resistance.

Coccidiosis

Be careful not to confuse nematodirus with coccidiosis which also causes scour in young lambs. Clinical signs of coccidiosis are a sticky grey diarrhoea that is often blood stained. Although similar in appearance, both diseases require markedly different treatment. Coccidiosisshould be treated/prevented by administering coccidiostats.

Grass tetany

Grass tetany may become more of an issue with lactating ewes grazing lush grass regrowth. Other trigger factors are tight grass supplies with high stress levels and poor weather (cold temperature or wet lush grass). Magnesium supplementation will help to prevent against its onset. Supplementation needs to be timely andbrisk as protection will only be provided once animals have achieved regular intake for one to three days. Protection will also disappear one to three days after supplementation has ended.

Magnesium can be given via high mag buckets, magnesium bullets, meal containing calmag or pasture dusting. Magnesium also can be given via water but this has variable success levels as grass tetany frequently hits in wet weather and sheep may not be drinking water.

Take care if feeding high magnesium meals that male lambs do not have free access. High intake can result in the formation of urinary calculi/stones resulting in blockages and death.

Worming yearling hoggets

Mature ewes in adequate body condition develop some level of natural immunity to worms. This natural immunity does not develop at the same rate for yearling hoggets rearing lambs. For this reason these animals may require worm dosing throughout the summer. Factors such as stocking rate, nutrition and grassland management will influence the worm burden present to ewes and lambs. Faecal egg tests will give important information on the requirement to dose.

As is the case with all live vaccines, great care is needed when handling and administering (human health) and manufacturers’ recommendations should always be followed.

*This article was orginally published in March 2012