Abattoir surveillance of Sarcocystis spp., Cysticercosis ovis and Echinococcus granulosus in Tasmanian slaughter sheep, 2007-2013.

OBJECTIVE: To estimate the prevalence of macroscopic Sarcocystis spp., Cysticercus ovis and Echinococcus granulosus recorded at routine postmortem inspection of Tasmanian slaughter sheep during 2007 to 2013. METHODS: A retrospective analysis of routine postmortem meat inspection data maintained on 352,325 Tasmanian adult slaughter sheep inspected across nine abattoirs in Tasmania, Victoria and South Australia as part of the National Sheep Health Monitoring Project (NSHMP). RESULTS: During the period 1 September 2007 to 30 June 2013, the estimated prevalence of macroscopic Sarcocystis spp. was 14.3%, C. ovis was 3.2% and E. granulosus was 0.01%. Mean Sarcocystis spp. line prevalence ranged from 0% to 33.5%. Significant between-abattoir differences in the level of sarcosporidiosis (P < 0.001) and C. ovis were found (P < 0.001). Overall, very low levels of hydatidosis were recorded throughout the surveillance period. Predicted within-line prevalence of macroscopic sarcocysts in animals coming from a known/recorded local government area (LGA) (P < 0.001) was lower than that of lines where the LGA was unknown or not recorded. A higher prevalence of sarcocystosis was recorded in lines of sheep aged ≥ 2 years compared with those < 2 years (P < 0.001). CONCLUSION: Reasons for the significant between-abattoir differences in recorded levels of ovine sarcosporidiosis and cysticercosis remain unknown, but may represent sampling bias, with subsets of slaughter sheep going to abattoirs with different tiers or access to markets. Further investigation into apparent differences, including epidemiological studies of properties with high lesion prevalence, comparing meat inspector diagnostic sensitivity, assessing the effect of line speed and tiers and market access in different abattoirs, may be useful.

Zinc oxide enriched peat influence Escherichia coli infection related diarrhea, growth rates, serum and tissue zinc levels in Norwegian piglets around weaning: five case herd trials.

BACKGROUND: Zinc oxide (ZnO), commonly used to control post-weaning diarrhea in piglets, has been highlighted as of potential concern from an environmental perspective. The aim of this field trial was to examine effects of different sources and levels of ZnO added to peat on average daily weight gain (ADG), fecal score in pens and serum and tissue zinc (Zn) levels around time of weaning in order to reduce the environmental impact without loss of the beneficial effect of ZnO on intestinal health and growth. Five case herds with enterotoxic colibacillosis challenges were included. The piglets entered the study aged three or five weeks. All piglets received a commercial diet containing <150 mg Zn/ per kg of complete feed. Four treatment groups received commercial peat added A: uncoated ZnO, B: lipid microencapsulated ZnO, C: solely commercial peat or D: no peat (Farms 2 and 3). RESULTS: At Farms 1, 2 and 3, a significant effect of treatment was identified for fecal score (P < 0.05). Treatment A led to lower fecal scores compared to treatments C (P < 0.05) and D (P < 0.01). At Farms 2 and 3, there was a significant difference in individual average daily weight gain (iADG) between treatment A and D (P < 0.05). The iADG of piglets receiving treatment B did not differ significantly from treatment A. CONCLUSIONS: In 2016, The European Medicines Agency's Committee on Veterinary Medicinal Products concluded that the benefits of ZnO for the prevention of diarrhea in pigs do not outweigh the risks to the environment. Effective alternative measures to reduce the accumulation of Zn in the environment have not been identified. Our results imply that peat added low concentration of both coated and uncoated ZnO influences the gut health of weaned piglets reflected by enhanced weight gain and reduced occurrence of diarrhea. This preventive approach certainly represents a favourable alternative in the "One Health" perspective. It will also contribute to reduced antibiotic use in pig farming while diminishing the environmental consequences caused by ZnO.

Inter-observer agreement for clinical examinations of foot lesions of sheep.

In sheep, the diagnosis of foot lesions is routinely based on physical examination of the hoof. Correct diagnosis is important for the effective treatment, prevention and control of both infectious and non-infectious causes of lameness. Therefore, the aim of this study was to evaluate the level of inter-observer agreement for clinical examination of ovine foot lesions. Eight observers of varying experience, training and occupation performed foot examinations on a total of 1158 sheep from 38 farms across North England and Wales. On each farm, a group of two to four observers independently examined a sample of 24 to 30 sheep to diagnose the presence or absence of specific foot lesions including white line lesions (WL), contagious ovine digital dermatitis (CODD), footrot (FR), inter-digital dermatitis (ID) and toe granuloma (TG). The inter-observer agreement of foot lesion assessments was examined using Fleiss kappa (κ), and Cohen's κ examined the paired agreement between the test standard observer (TSO) and each observer. Scoring differences with the TSO were examined as the percentage of scoring errors and assessed for evidence of systematic scoring bias. With the exception of WL (maximum error rate 33.3%), few scoring differences with the TSO occurred (maximum error rate 3.3%). This suggests that observers can achieve good levels of reliability when diagnosing most of the commonly observed foot conditions associated with lameness in sheep.

Inter-observer agreement, diagnostic sensitivity and specificity of animal-based indicators of young lamb welfare.

A scientific literature review and consensus of expert opinion used the welfare definitions provided by the Farm Animal Welfare Council (FAWC) Five Freedoms as the framework for selecting a set of animal-based indicators that were sensitive to the current on-farm welfare issues of young lambs (aged ≤ 6 weeks). Ten animal-based indicators assessed by observation - demeanour, response to stimulation, shivering, standing ability, posture, abdominal fill, body condition, lameness, eye condition and salivation were tested as part of the objective of developing valid, reliable and feasible animal-based measures of lamb welfare The indicators were independently tested on 966 young lambs from 17 sheep flocks across Northwest England and Wales during December 2008 to April 2009 by four trained observers. Inter-observer reliability was assessed using Fleiss's kappa (κ), and the pair-wise agreement with an experienced, observer designated as the 'test standard observer' (TSO) was examined using Cohen's κ. Latent class analysis (LCA) estimated the sensitivity (Se) and specificity (Sp) of each observer without assuming a gold standard and predicted the Se and Sp of randomly selected observers who may apply the indicators in the future. Overall, good levels of inter-observer reliability, and high levels of Sp were identified for demeanour (κ = 0.54, Se ≥ 0.70, Sp ≥ 0.98), stimulation (κ = 0.57, Se = 0.30 to 0.77, Sp ≥ 0.98), shivering (κ = 0.55, Se = 0.37 to 0.85, Sp ≥ 0.99), standing ability (0.54, Se ≥ 0.80, Sp ≥ 0.99), posture (κ = 0.45, Se ≥ 0.56, Sp = 0.99), abdominal fill (κ = 0.44, Se = 0.39 to 0.98, Sp = 0.99), body condition (κ = 0.72, Se ⩾ 0.38 to 0.90, Sp = 0.99), lameness (κ = 0.68, Se > 0.73, Sp = 1.00), and eye condition (κ = 0.72, Se ≥ 0.86, Sp = 0.99). LCA predicted that randomly selected observers had Se > 0.77 (acceptable), and Sp ≥ 0.98 (high) for assessments of demeanour, lameness, abdominal fill posture, body condition and eye condition. The diagnostic performance of some indicators was influenced by the composition of the study population, and it would be useful to test the indicators on lambs with a greater level of outcomes associated with poor welfare. The findings presented in this paper could be applied in the selection of valid, reliable and feasible indicators used for the purposes of on-farm assessments of lamb welfare.

Impact of footrot vaccination and antibiotic therapy on footrot and contagious ovine digital dermatitis.

Footrot and contagious ovine digital dermatitis (CODD) are common causes of foot disease of sheep in the UK. The study reported here is a split flock randomised treatment trial undertaken on a group of 748 fattening lambs on a UK sheep farm affected by CODD and footrot. The sheep were randomly assigned to one of two treatment protocols. In protocol A, all sheep were given two doses of footrot vaccine (Footvax, MSD), plus targeted antibiotic therapy (long-acting amoxicillin, Betamox LA, Norbrook Pharmaceuticals) to sheep with foot lesions likely to be associated with a bacterial infection. In protocol B, the sheep only received targeted antibiotic therapy. Sheep were re-examined and foot lesions recorded five and nine weeks later. New infection rates in the footrot vaccinated group were lower compared with the vaccinated group for both CODD (18.2 per cent compared with 26.4 per cent, P=0.014) and footrot (12.55 per cent compared with 27.5 per cent, P<0.001). Recovery rates were unaffected for CODD (80.46 per cent compared with 70.97 per cent, P=0.14) but higher for footrot (92.09 per cent compared with 81.54 per cent, P=0.005) in sheep which received the vaccine. On this farm, a footrot vaccine efficacy of 62 per cent was identified against footrot and 32 per cent against CODD infection. An association between a sheep having footrot at visit 1 and subsequently acquiring CODD was identified (odds ratio [OR] 3.83, 95 per cent CI 2.61 to 5.62, P<0.001). These results suggest a role for infection with Dichelobacter nodosus in the aetiopathogenesis of CODD on this farm.

Validating indicators of sheep welfare through a consensus of expert opinion.

A consensus of expert opinion was used to provide both face and consensual validity to a list of potential indicators of sheep welfare. This approach was used as a first step in the identification of valid welfare indicators for sheep. The consensus methodology of the National Institute of Health, using pre-meeting consultation and focus group discussions, was used to ascertain the consensus opinion of a panel of sheep welfare experts. The Farm Animal Welfare Council's five freedoms were used as a framework to organise a list of current on-farm welfare issues for sheep. The five freedoms were also the welfare criterion used to identify potential on-farm welfare indicators for sheep. As a result, experts identified 193 welfare issues for sheep and lambs managed on farms across England and Wales. Subsequently, a combination of animal- (n = 26), resource- (n = 13) and management- (n = 22) based indicators was suggested for (i) adult rams, (ii) adult ewes (male and female sheep, over 1 year old), (iii) growing lambs (male and female sheep, over 6 weeks to 1 year old) and (iv) young lambs (male and female lambs, 6 weeks old and under). The results from this study could therefore be used to inform the further development of valid methods of assessing the on-farm welfare of sheep.

Effects of parenteral amoxicillin on recovery rates and new infection rates for contagious ovine digital dermatitis in sheep.

The present study is a randomised split-flock treatment trial, which compared the effect of foot bathing in a 1 per cent solution of chlortetracycline alone with a treatment protocol that added a single injection of a long-acting amoxicillin. Overall, the prevalence of contagious ovine digital dermatitis in the examined flock was 22 per cent, while 45.7 per cent of affected sheep had infections in two or more feet. Parenteral antibiotic treatment increased the odds of a recovery by 3.8 times (95 per cent confidence interval 1.05 to 14.0) (P=0.008). Moreover, the amoxicillin injection may also have had a preventative effect, reducing the rate of establishment of new infections from 2.5 per cent for foot bathing alone compared with 1.0 per cent with the addition of parenteral amoxicillin.