CASE NOTES


NSW SHEEP REPORT, SPRING 2012

Bruce Watt, SDV Tablelands

After some wet seasons, it is turning dry across most of NSW. Steve Eastwood (Armidale) commented, ‘we have had a very dry start to the spring season. As a result, things have been very quiet. Like rain, feet issues, flies and worms are nowhere to be seen.’ On the central tablelands, pastures are wilting while Colin Peake (Hay) remarked that ‘the Western Riverina has become quite dry since the March rains.’

The proposed changes to OJD management have caused interest and concern for NSW sheep producers. For most of us in the previous high prevalence area, it is business as usual with vaccination underpinning OJD prevention, although Eliz Braddon (Young) commented that she still sees the occasional case of OJD in higher prevalence flocks and Bill Johnson sees OJD in unvaccinated rams imported from areas with a low prevalence of OJD. Eliz commented that most cases of OJD first become apparent at pregnancy or lambing. Eliz also investigated ‘Gudair staggers’ in a flock belonging to a first time vaccine user.

However, to the west and north the proposed changes may have more impact on producers. Jillian Kelly (Dubbo) mentioned that ‘the OJD changes are a hot topic of discussion around Nyngan and Coonamble at the moment. The two meetings held drew an enormous crowd and in both locations, there was a unanimous vote to go for Protected Status. We are still fielding calls regarding the changes and explaining the implications to farmers.’ Colin Peake mentioned that the new OJD Management Plan is causing angst in his part of the world (the western Riverina). Colin asks ‘why can’t all Low Prevalence areas automatically become a Protected Area?’

Some of us have collaborated with the irrepressible David Jenkins from CSU in his two-year MLA funded project on sheep measles. David has commented that while sheep measles ‘did not pose a problem for public health, the downgraded and condemned meat was a cost for abattoirs and a potential trade barrier.’ David aims to investigate the risk factors for the transmission of the parasite including dog feeding and worm control. He is also looking from the presence of the tapeworm in foxes and wild dogs. As part of this study, David recently collected a consignment of 52 dead foxes from the central tablelands. Jillian Kelly is also collaborating and commented that farmers (but not vets) from the Nevertire region ‘have been collecting dog poo from their working dogs and sending it to David who looks for tapeworm eggs. To date, there have been no tapeworms detected, and we plan to look at the fox population next.’

Jillian also reported a case of hypocalcaemia/rickets in weaner sheep grazing an oats crop near Nyngan. She found that 90% were stiff or lame and 6/300 fractured their legs. Jillian tried supplementation with lime and salt, which did not alleviate the problem. ‘Eventually the sheep were moved into a grass paddock, supplemented with lucerne hay plus the lime and salt. I spoke to the farmer just this morning, and he tells me that they have improved out of sight, both in lameness and condition.’ Ian Masters (Gundagai) investigated hypocalcaemia, causing losses in ewes and lambs that had been yarded for shearing and other procedures. The sheep had been grazing wheat crops. Ian also commented that M. ovis has been responsible for ongoing light losses in mulesed merino weaners in the western part of this district.

Colin Peake saw presumed hypocalcaemia in weaner sheep in a saleyard. They had been mustered, drafted and left in yards day 1, trucked to the sale yard on day 2, spent day 3 in the saleyard with water and poor quality hay/straw, day 4 drafted, to sale pens and then started dying. Adding to their woes, a cold snap came through on days 3 and 4. Colin treated the down lambs with a CBG 4 in 1 mix both iv and s/c, saving 18 from 25. Colin performed an autopsy on a dead lamb and found that the rumen was empty. He concluded ‘this was a stress induced metabolic problem in young sheep not knowing how to eat hay and drink from a trough in a new environment during a cold snap.’ Bill Johnson (Goulburn) also diagnosed hypocalcaemia in yard-weaned lambs given access to cereal grain and poor-quality oaten hay with no supplementary calcium.

Amy Shergold (Wagga) reported a case of dermatosparaxis in Dorpers. Following the purchase of four new rams, two lambs were found to be affected. Amy commented that ‘both lambs were destroyed at only a few days of age following failed attempts to suture skin lacerations. Further damage was caused by restraining lambs in the cradle.’ The owner will now use the test kits provided by the Dorper society to screen all rams in the flock, only using rams free of the defective gene.

Amy also described a mystery case of profuse diarrhoea in 3-4 month old SAMM lambs in which 100 of 400 died. The diarrhoea progressed over 4-5 days. Amy commented that the ‘ewes remained unaffected and 2 other mobs of similar lambs that were run in separate pastures also remained healthy. Worm tests, coccidia and bacterial profiles were all negative. No abnormalities were detected on PM of one clinically affected lamb.’ The lambs were running on a lucerne and clover pasture and were supplemented with hay. No further cases occurred within 24 hours of the lambs being moved onto a new pasture.

Enterotoxaemia has caused some losses in NSW. Jillian Kelly commented on a farmer who experienced a second outbreak of ET in four years, ‘the farmer still doesn’t believe in vaccination (even after the second round of losses!).’ Eliz Braddon has also received reports of pulpy kidney in incompletely vaccinated lambs.

Bill and I have both seen disease and mortality in sheep from acute and chronic liver fluke. Bill observed the first losses in paddocks, adjacent to watercourses, that had been inundated for several weeks. ‘Subsequently, problems were reported from more traditional tablelands habitats, associated with springs and swampy areas that hadn’t run water for much of the past decade of drought.’ Bill also saw a case of closantel toxicity causing blindness in the lighter end of a mob of weaners that received an estimated five times the recommended dose. ‘All up, about five percent of the mob perished or was euthanased following development of permanent blindness.’

Finally, as usual, worms caused losses across the state. In the far southwest, Colin Peake noted little worm activity. However, further east as Bill Johnson remarked, ‘internal parasites’ was the answer to the most frequently asked question ‘why are these sheep dying?’ Bill reported that a couple of mobs of lambing ewes experienced losses of more than ten percent of ewes, due to re-infection with Teladorsagia and Trichs. Tony Morton (Wagga), Ian Masters (Gundagai), Eliz Braddon (Young) and Jim MacDonald (Yass) have similar comments to Bill, seeing problems with Trichs and Teladorsagia and early cases of Haemonchus. The DVs presume that these Haemonchus cases are from larvae that have persisted from last autumn with newly infected sheep adding to the counts. Ian has seen a case of anaemic lambs dropping out when mustered for weaning early this spring. ‘They had a high FEC and were scouring so probably had a bit of everything.’

Ian also commented on increasing ML resistance. ‘On one property the mectin treated group had a higher FEC than the controls but are mostly reducing FEC’s by 70-80%.’ Eliz Braddon (Young) reported a similar situation with plenty of scouring, illthrifty lambs/weaners and ewes. Eliz added ‘I have just diagnosed the first Haemonchus case of the season in some lactating ewes so I guess we may be in for an earlier attack than the previous two years due to pasture contamination.’ Jillian Kelly has also seen cases of haemonchosis and some high WECs in the central west. Jim Macdonald concluded ‘in adult ewes, counts of 500 epg at lamb marking are common. Pasture contamination in most paddocks is extremely high and will remain so until end of November at the earliest. Parasite burdens will continue to haunt sheep producers to at least Christmas.’

 


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