Much of NSW is experiencing dry conditions, which suits the wheat harvest but has curtailed the spring on the tablelands.
Kasia Hunter based at Condobolin reported an interesting case of coccidiosis and hypocalcaemia in a mob of 200 young early weaned Dorper and Dorper X lambs. Kasia commented; ‘many of the lambs were < 15 kg and were held off feed for transport and sale via Forbes saleyards. After the sale, they were then held at the saleyards before transport to the new property. They were marked then run in a small weedy paddock and were offered oaten chaff and hay with bentonite blocks which they barely touched.’ Kasia noted that approximately 40 in the mob developed scours and 20 died prior to her visit. However, once the lambs were fed pellets and oats plus lime and salt and drenched with sulphadimidine the deaths stopped and no new cases of scouring occurred.
DVs report a range of lameness investigations. During the wetter early spring (now a distant memory), I investigated benign footrot (in lambs only) on three properties. The disease was characterised by marked lameness in about 20-30% of the mob with severe OID but no underrunning and with a rapid response to foot bathing in zinc sulphate. Tony Morton (based at Wagga) also saw in large numbers of XB lambs with feet lesions consistent with benign disease. These lambs also responded to zinc sulphate foot bathing.
Kasia saw two cases of foot abscess in ewes associated with spring rain and wet conditions at Condobolin. In both cases, approximately 10% of the flock was affected. Both mobs of sheep had been recently purchased from dry northwestern NSW and developed foot abscess within 2 weeks of arriving onto the local properties. Belinda Edmonstone has also been called to several cases of foot abscess. Amy Shergold based at Wagga investigated a case in which 10 of 18 young rams had foot abscess in post joining while 5-10 of the 2,000 ewes were affected. Foot abscess in young rams is more frequently reported in New Zealand than Australia while in New Zealand, I understand that foot abscess is less common in ewes. In the case Amy reported, the rams were running on good but not lush and wet feed; however, they had been walked along a gravel road.
Amy investigated a case of ovine brucellosis in which five of 10 Border Leister rams had palpable lesions while seven of 10 were seropositive. Amy noted that the lambing percentage was 100 percent after an 8-week joining. The owner plans to cull all rams and restock from accredited free flocks. Of interest, this farm neighbours a property diagnosed with ovine brucellosis last month.
Amy also reported that 20 of 90 Dorper ewes aborted with the main post-mortem findings in the lambs being goitre and agnathia/ aglossia in one twin and extra-thoracic thymic tissue around the larynx in both twins. The ewes grazed lucerne and pasture that included some capeweed and Patterson’s curse present. They had also been fed some damp and musty clover hay in May but no silage was fed. Toxoplasma serology on foetal fluids and Campylobacter bacteriology were negative.
In a follow-up visit, revealed Amy observed a swelling of the ventral neck consistent with goitre in 85 of 87 well-grown unweaned lambs. ‘An abnormally sparse and wiry fleece (although they are Dorpers!) was also seen in some animals typical of hypothyroidism.’ She did not see any goitrogenic plants on the property and instituted supplementation with iodised salt.
With the drier season, internal parasites seem to have been less of a problem. Bill Johnson (Goulburn) found that Haemonchus continued to predominate in worm egg count monitoring across the district during June, but there were only a few reports of clinical disease. Of interest and consistent with recent survey findings, Bill reported worm egg counts of couple of thousand and 99% Haemonchus in ewes drenched with abamectin two weeks previously. The property has used abamectin exclusively for the past two years. Ian Masters commented that ‘in the Gundagai region, Barber’s pole worm has been responsible for light losses in young sheep on two holdings recently and a lot of larval differentiations over recent months are showing BPW at 50-70 percent of the worm population.’ Bob Templeton based at Braidwood has also seen hoggets, adult ewes and weaners die from Haemonchosis. He attributes much of this to poor drench selection. Earlier in the spring, I also saw deaths from Haemonchus in the Bathurst district. I attributed this to a pasture contamination in the autumn. Elsewhere in southern NSW, the winter worms have also caused problems.
Bill Johnson diagnosed "capsule cellulitis" in 7 of 300 adult merino ewes on point of lambing. Bill commented that ‘the ewes died within 5 days of treatment, heads down with copious nasal discharge. The owner had used drench capsules without incident in previous years, but had assistance on this occasion. It was noticed that the helper occasionally used a "stabbing action" to deliver the capsule.’ ‘In a fatal variation of sword swallowing, one capsule was found at the thoracic inlet, having exited the GIT through a hole in the dorso-caudal pharynx.’
Bill also noted that liver fluke are increasing on properties where they have previously been recorded. ‘Routine fluke treatments were suspended on many of these properties through the drought, and some owners have been slow to recognise the need to re-commence the program.’
Both Bill Johnson and Belinda Edmonstone saw cases of enterotoxaemia. Bill confirmed enterotoxaemia in older weaned lambs on fresh lucerne, and in 11 week old second cross lambs on lush pasture about to receive booster vaccination. Bill also saw a case of grain poisoning in young wethers recently introduced to full grain feeding with Eskalin-treated wheat. ‘The inclusion level of Eskalin was about half that recommended.’
Earlier this spring, Bill reported that heavy rainfall (130mm over 36 hours) took a toll on recently shorn sheep. One affected owner who lost about 700 hoggets described significant losses in his finewools, and virtually no deaths in his Monaro-blood sheep run in the same mob. Bill speculated ‘perhaps they benefitted from ‘selection of the fittest’ over generations of Monaro winters’ The owner observed the sheep appeared OK while it was just raining, but packed up along fences and in gullies when the wind started. He attributed many of the losses to smothering. Of interest, the deaths occurred despite the sheep having been treated with Thermoskin® off shears. However as Bill commented, ‘even the owner admitted the product would have been hard-pressed to withstand these conditions; instead he wondered how many more he may have lost without it.’
Finally on neurological matters, Belinda Edmonstone reported a case of phalaris staggers while Jill Formosa was called to a case on a fine wool property running 2,000 ewes in the Mudgee district in which two 12 month old wethers progressively developed a weak swaying gait in the hindquarters. Segmental axonopathy was confirmed on histology.