CASE NOTES


NSW SHEEP REPORT WINTER 2012

Bruce Watt, SDV Tablelands

Haemonchosis continues to kill sheep across NSW. A few days ago, a prime lamb producer presented me with an ill-thrifty lamb, eight weeks of age and still on its mother, because he has lost about 40% of his lambs. The lamb was anaemic, with a PCV of nine and an abomasum full of Haemonchus. This case is unusual because it is associated with ill thrift, it occurred in July and it is in a young lamb. To date I have only had the chance to look at this single lamb and suspect there is more going on than Haemonchus but it is interesting nonetheless. Bill Johnson from Goulburn commented on a case of clinical haemonchosis in a mob of Dorpers, reminding us (as we know from the work of Lewis Kahn and others) that frost doesn’t kill barber’s pole worm larvae. Haemonchus continues to be present in about half the faecal cultures in the Goulburn district.

Belinda Edmonstone from Forbes mentioned that BPW remains the main issue in her area although she is seeing problems with scour worms as well. Bill Johnson also reports scour worm problems. ‘Seasonal conditions to date have been similar to 2011, a year in which many ewes died around lambing from heavy scour worm infestation.’ Several flock owners have used long-acting drench capsules for the first time. Consequently deaths from ‘capsule cellulitis’ have increased. ‘The expensive foreign body usually lies in the cranial cervical area, with cellulitis tracking down the ventral cervical muscle planes to the thoracic inlet. The associated septicaemia causes carcases to decompose rapidly, or at least faster than expected at Goulburn in winter!’

While BPW is also a problem on the mid-north coast, Ian Poe commented that sheep suffer from a range of conditions in his region. ‘Contrary to popular belief it’s not just barbers pole and wild dogs in the few sheep we have here on the coast - though they continued to be a popular cause of demise. I also saw a case of dermatosparaxis in Dorpers (luckily I had been to the DVs conference and knew all about it) and a case of abortion in which the lab isolated Enterobacter cloacae.’ Great to hear that sheep medicine is alive and well on the north coast (even if the sheep aren’t).

On the subject of Dorpers, Colin Peake based at Hay, reported that he is finding brucellosis in the testing he is conducting. Colin speculates that OB can run rife in this breed. Tony Morton, based at Wagga Wagga (like New York, New York, so good they named it twice) mentioned a case in which 25 of 1,000 merino ewes died from middle ear abscesses. Affected ewes separated from the mob, developed a head tilt, a drooping ear, weakness and a tendency to fall onto their sides. Tony hypothesised that ‘the ears must have contained grass seed when dipped (pastures were very long with plenty of seed heads waist high) and either it has acted as focus of infection or it actually germinated and that set off the infection.’ Tony added, ‘I cannot recall any similar problem with middle ear infections and plunge dipping before.’

Bill Johnson commented that owners of early-lambing flocks report a higher than usual prevalence of vaginal prolapse, in both crossbred and merino ewes, with a high mortality rate. Affected ewes are usually fat with multiple foetuses. I have also spoken to several producers about vaginal prolapse. It continues to frustrate many who report limited success with treatment. I have also seen the problem in merinos that are not in fat condition. In the few cases in which I have had the sub clover species identified, oestrogenic clovers have not been a problem. Bill also reports that the spectacular condition, spontaneous vaginal rupture has occurred this season in flocks in the Goulburn area.

Belinda Edmonstone based at Forbes commented on the foot issues that presented after the rain and floods in Feb/March. These included foot abscess in rams and pregnant ewes and foot scald in lambs. Belinda reported a distressing case in which 800 maiden ewes were caught in flood water for five days. ‘A few weeks later it was noted that the skin below their knee/hock was sloughing off to varying degrees. They did not lose the horn of their claws.’ However, the producer feels that attempts at treatment by protecting wounds from flies and infection ‘was relatively unsuccessful and a lot were destroyed over the following months. He now has about 300 left.’

Bill Johnson mentioned a case in which internal parasites then OJD seriously eroded the profit from a live export wether venture. ‘Purchased as lambs, the unvaccinated western wethers first had to battle through one of the worst worm years on the tablelands. A significant number died, and a large tail developed on the mob. Heading into their third year with the tops already sold, the tail has failed to thrive, despite good feed and parasite control. Thirty of 1200 have died from OJD in the past six weeks. Routine Gudair vaccination of locally bred sheep has been so effective in preventing this once familiar picture that southern tablelands producers occasionally forget not everyone does it.’

Many of us have taken calls and visited farms with ‘pink eye’ in sheep. I have probably mentioned this before but I occasionally take calls from experienced sheep producers concerned about their blind sheep. While the differential diagnosis including Stypandra toxicity, PE, preg tox, closantel toxicity and vitamin A deficiency runs through my mind, it is mostly keratoconjunctivitis. Cattle producers may call for advice on the management of pink eye but never for a diagnosis. I think this is because pink eye in sheep occurs in sporadic, infrequent outbreaks whereas in cattle it occurs routinely, especially in calves in the autumn. Pink eye is also less obvious in many sheep with corneal oedema and peripheral neovascularisation the main features compared to marked epiphora and central corneal ulceration in cattle. Others have similar experiences. Belinda Edmonstone commented, ‘over autumn we also had a lot of phone calls about blind sheep that always turned out to be pink eye.’ Colin Peake also saw pink eye, chlamydia CFT negative, in 3-4 month old crossbred lambs with pink eye. It resolved spontaneously. In the Yass district, Jim McDonald noted that ‘pinkeye in lambs and hoggets has raised its head here in June/early July.’

Several DVs from across NSW mentioned pregnancy toxaemia associated with declining feed quality and quantity as lambing approaches. Jillian Kelly has had several reports of preg tox in the Nyngan and Coonamble districts. Most cases are in ‘twin bearing ewes are requiring supplementation with grain as the summer grass is not supplying their energy requirements.’ Bill Johnson noted that ‘various combinations of worms, foot abscess, management stressors, short pasture and even tooth loss in maidens have been responsible for “multi-factorial” pregnancy toxaemia cases in many flocks. Response to treatment has been particularly poor.’ Andrew Biddle based at Glen Innes reported pregnancy toxaemia in ewes joined early, in reasonable body condition ‘but have been on a sliding plane of nutrition since joining.’ Andrew added that ‘recent rain and heavy frosts have taken any remaining nutritional value out of dry standing feed’ so ‘bring on an early spring!.’ Jim MacDonald noted the first case of pregnancy toxaemia in his district post the rough weather in early July.

Weaners, as is their want, have also suffered from ill thrift in the Glen Innes region. Andrew notes an alliance of ‘fluke, Trichs, bacterial enteritis and Mycoplasma ovis’ appear to be sapping the will to live of these sheep.

Jillian Kelly based at Dubbo reports a most interesting case of stillborn Dorper lambs near Nyngan. ‘On post mortem, these lambs were normal birth weights, fully developed, had not walked nor suckled but had breathed. Histopathology found diffuse tubular necrosis in the kidneys, which appears secondary to the presence of an extreme number of oxalate crystals.’ Jillian added that ‘it has been reported that cows grazing oxalate containing plants or mouldy feedstuffs can abort their calves, with similar findings on histopathology, but this problem has not been seen in sheep.’ Jillian and an agronomist walked the paddock but were unable to find plants known to contain oxalates. There is also no history of the ewes grazing these oxalate rich plants throughout their pregnancy and no evidence of hypocalcaemia in the ewes.

Jillian also said that the Central North LHPA team has taken many phone calls from farmers subsequent to Fletchers abattoir posting feedback reports to producers. Many consignments have Cysticercus ovis (sheep measles) and Cysticercus hydatigena (bladder worms). ‘We have made it a priority to educate farmers at our fox bait meetings and in local media about this problem, and the benefits of regularly worming farm dogs, not feeding offal to dogs and baiting for foxes.’

 


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