Navel/joint ill: Pressure on housing is increasing the risk of joint or navel ill establishing. The disease is linked directly to a bacterial infection that gains entry via the navel and spreads via the lamb’s bloodstream to the joints, where it causes bacterial arthritis.
The tell-tale signs are well documented, and established cases can be readily identified by swelling in one or more joint in the front or back legs. The incidence rate is reported as split 50:50 between one or multiple joints being affected.
Veterinary advice highlights three critical control aspects. The first of these is lambs born into a clean environment, followed by prompt disinfection of the navel with a product formulated at the correct dilution rate. Where the dilution rate is incorrect and formulated at too high a concentration, it can damage the soft tissue of the navel and actually increase the risk of infection establishing. Likewise, an inadequate dilution rate will not provide the required protection.
Iodine solutions are generally traded at 10% dilution rates. Some vets favour reducing the dilution rate to 3%-5%, while others prefer the use of chlorhexidine and alcohol-based disinfectants.
Opinions also differ on navel dipping or spraying. Some cite navel dipping as a better alternative, while others say the solution can lose efficacy if not replaced regularly. Irrespective of the method selected, it is important to ensure the entire navel is treated sufficiently. Farmers encountering significant problems often find a repeat navel treatment after a period of two to four hours can help.
Treatment success is dictated by speed of intervention. Vets generally prescribe a course of antibiotics and anti-inflammatory drugs administered over a period of a few days, or alternatively, long-acting antibiotics which require repeat treatment at longer intervals.
The prognosis is poor for advanced cases, with lambs frequently struggling to regain normal levels of performance or suffering long-term lameness. Issues also crop up frequently at this time of year with tail-end lambs that have suffered from the disease and show up with liver abscesses or peritonitis, which can have implications for carcase quality and increase the risk of partial or complete carcase condemnation.
Grass supplies: Flocks lambing in the coming weeks should walk areas earmarked for grazing first, to see what grass supplies are like. Reports suggest there is a significant difference in how farmers are fixed, with some who closed ground earlier, due in part to being forced to house ewes earlier, in a relatively good position if growth comes good while others who closed areas late or borderline on their target date are looking as if grass supplies will be tight.
Current growth rates are poor and are being curtailed by low soil temperatures. Opportunities to get fertiliser applied are also a non-runner for a large percentage of sheep farmers on more marginal ground. With fertiliser prices increasing, the advice is to capitalise on opportunities to spread early nitrogen, as even at the higher costs there will be a return where it is applied in the correct conditions.
This should be the focus and applications should be delayed or split where conditions are not right for applying. Where grass supplies are likely to be deficient, then plans will need to be put in place in advance to reduce demand and conserve existing supplies until growth improves.