CASE NOTES


NSW STATE REPORT SPRING 2011

Bruce Watt, Tablelands LHPA, Bathurst

Internal parasites continue to cause significant losses over much of the state. Andrew Biddle (Glen Innes) commented that Haemonchus egg counts are higher than usual indicating an early start to the problem while Libby Read at Narrabri noted similar problems. Bill Johnson based at Goulburn commented:

'producers remained preoccupied with worm-related deaths and illthrift until mid-spring. The fallout from black scour and brown stomach worm problems in lambing ewes continues, with both lambs and ewes lighter at weaning than last year ... without careful management, lamb survival over summer will be compromised, as will the ability of ewes to regain condition prior to joining. Some mobs also carry unusually high Haemonchus burdens for this time of year.'

Helen McGregor and Tony Morton from the Wagga office have also seen internal parasite problems related to previous pasture contamination:

'Counts over the last month have generally been higher than normal reflecting the ongoing problems since the wet summer of 2010/2011.There have even been situations where lambs have required drenching pre weaning.'

On the bright side, the high counts have provided ideal opportunities for drench resistance tests.

Tony cited an example of rapid re-infestation following effective drenching as an illustration of the level of pasture contamination experienced on some occasions. He noted a surprising total worm count from a case where worms were seen to be moving quite vigorously within the opened abomasum. EMAI identified Teladorsagia (Ostertagia) as the culprit rather than immature Haemonchus as Tony expected from the movement observed. The other interesting finding was that the lambs had been drenched 01.08.2011 with Triton, again 28.08.2011 with Triton , four weeks after the last drench had only 44 e.p.g and yet two weeks later had a huge burden of Teladorsagia (based on TWC, not a WEC). A further drench with ivermectin gave an excellent kill (based on TWC) so the problem was reinfection not resistance.

Phosphorus deficiency, while a well recognised problem in cattle is rare in sheep. Bill Johnson however, has evidence of the problem in his area. He reports:

'ewes raising twins in a small Dorper flock displayed marked lameness, involving all legs in the worst-affected. They had low serum phosphorus with normal calcium and vitamin D, and responded to phosphorus supplementation.'

Bill wondered if this was a consequence perhaps of running higher-producing animals on what was previously finewool merino country.

Tony Morton/Helen McGregor diagnosed chlamydial arthritis in autumn/winter drop Poll Dorset stud rams. They comment:

'this property has a history of erysipelas arthritis in the BL stud ram weaners (spring drop) and as result all Border Leicester and Poll Dorset ewes were vaccinated. Initially 14 ex 140 lame rams were culled , two weeks later there were a further 19 lame, acute and convalescent sera samples were consistent with chlamydial infection and the affected rams responded very well to two injections with a long acting tetracycline. The owner decided to inject all the mob in the hope of breaking the disease cycle, a few weeks later a further 3 rams went lame.'

Tony/Helen also commented that they have seen arthritis and wound infection in sheep dipped on week off shears. They consider that the use of contractors for plunge dipping and difficulties of obtaining their services is putting pressure on some farmers to dip too early. Greg McCann and Evelyn Walker (Dubbo) both also report problems post-dipping. Greg noted that 30% of a mob of 900 hoggets dipped straight off the boards were lethargic with:

'typical droopy ears and looked tucked up.'

The dip did not have any antibacterial additives and the wether hoggets were dipped last. Greg commented that treatment of the entire mob with OTC stemmed the problem, but not before another 30 animals died to add to the 30 that had died prior to treatment. A 'hospital' mob of 50 animals was isolated and retreated. Most of these were going to make a full recovery, but a large percentage suffered a fleece break. About 20% of this hospital mob was showing joint involvement.

Evelyn Walker reported that a first time dip user, who used no antibacterial additives, dipped a mob of 800 8-10 mo merino lambs 14 days after shearing. The young sheep were dipped after the main (older & lousy) mob was dipped. An inspection of the mob 10 days later, showed that about 100 had developed severe generalised cellulitis and joint involvement. This mob also suffered a percentage of fleece breaks and fly strike.

Phalaris staggers continues to cause losses. As reported in the previous edition of this report, the disease was reported from central western NSW to the south and east. Until this year, I had not seen significant phalaris staggers in the central tablelands since I first arrived here in 2006. However, I have seen several cases this year including some on Tablelands basalt and cases on Cowra red loam, soil types normally expected to have cobalt levels adequate to be protective. Dan Salmon (Deniliquin) comments:

'I have seen two cases of phalaris staggers in the past 6 months after not having seen any in the previous 38 years.'

Dan added:

'footrot is on the go, usually in sheep which have been introduced in the past couple of years.'

He also noted that there have been some horrendous reports of grass seed infestations while worms and pulpy kidney have not been anywhere near as bad as last year.

Finally, David Thomson remarked on the difficulties faced by those hardy souls who run sheep on the north coast. He noted that the causes of losses around Grafton have been dogs first and worms second. David also commented that Zolvix was effective when combinations had not been, amongst small blockies with minimal infrastructure or capacity to spell pastures.

 


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