Vetwatch: Nematodirus risk high

Iain Richards: Westmorland Vets, Cumbria

The cold winter will have one more trick to play this spring. Nematodirus is well known for causing severe losses in growing lambs. For the egg to hatch it needs a period of cold weather, then, once warm weather arrives, they hatch in large numbers.

When spring conditions are mild and there is gradual warming, eggs hatch in smaller numbers which lambs can cope with. However, when a cold winter is followed by a sudden period of warm weather, a mass hatch can occur. This leads to high numbers in lambs, scour and death.

Egg counts are of limited use as disease occurs before the adults lay eggs. Prevention is best done by avoiding fields grazed by last year’s lambs, while treatment is best done with a white drench.

With the hard work of lambing mostly over, attention must now switch to minimising lamb losses over the forthcoming months. Immunity to clostridial diseases via colostrum from vaccinated ewes begins to wane at about 12 weeks of age.

Boosting lambs with a primary course of one of the clostridial vaccines provides continued immunity against these diseases.

The risk of certain clostridial diseases such as pulpy kidney can also be reduced by good feeding practices, such as avoiding abrupt dietary changes and ensuring there is no interruption of creep feed supply to lambs. It will be interesting to see how farmers view the continued threat of bluetongue virus and how many continue to vaccinate against this potentially devastating disease in sheep.

I recently saw a 12-month-old heifer with symptoms similar to listeria (blindness, unsteady, no appetite and depressed). She wasn’t, though, circling.

It was only when she passed some dark brown urine that copper toxicity came to mind. She had never been outside and had been on a standard rearer nut and haylage diet since weaning.

After exhaustive post-mortem diagnostics, the conclusion of copper poisoning was reached.

The feed company said many heifers were fed this nut at up to 4kg a head a day, and checked copper levels in the last few batches; all were ok. However, for ease of management, the heifers had been fed ad lib from weaning until a few weeks before this event. It hadn’t been advised to feed ad lib. Total weight of nuts fed had been about 4kg max, but it seems this one had overindulged. Lesson learned.

Andrew Davies: Synergy Farm Health, Dorset

Calf rearing and heifer management have been a focus for the practice in recent times, but certainly have come to the fore in the past few months. We are promoting the use of our mobile handling system and technician for regular heifer weighing and routine tasks.

Weight recording has highlighted nutritional, management and disease issues earlier than normal, allowing early and significant cost saving actions to be taken.

I have seen cases of pneumonia over the past month but, being involved with Farmskills training and workshops on youngstock management, I have really seen the benefits of farmers putting in to action what they have learned on the courses, instigating measures to prevent the devastating effects such outbreaks can have.