Fungi, including Pithomyces chartarum cause facial eczema and inflammation in grazing sheep in Western China.

Facial eczema is often found in flocks of grazing sheep in China. To investigate fungi species those cause disease and pathological roles. Forage and soil samples were collected during the pathogenic season and cultured. Samples were collected from regions with and without facial eczema affected sheep. Fungal isolation and identification, statistical analysis of fungal species and distribution were performed. Pathological changes, biochemical parameters of serum liver function and protection of inflammatory factors that tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-12 (IL-12) were observed. Fungal cultivation and identification showed that separation rate of Alternaria, Pithomyces chartarum, Fusarium and Aspergillus were higher, particularly, Pithomyces chartarum was significantly identical. Pathological anatomy and histology indicated that the disease likely attacked merino ewes with the age of 6 months old. The clinical manifestations were characterized by inflammational edema in face (ears and eyelids) and mandibular area. Postmortem examination of dead lambs showed enlargement of liver with yellow white patchs of necrotic lesion and tuberous sclerosis and fibrosis on section. Histologic examination of liver showed extravasated blood, severe lesion of liver cells and bile duct, and fatty degeneration. In sheep, fungal toxin induced the secretion of TNF-α, IL-6 and IL-12. These results revealed that Pithomyces chartarum maybe caused facial eczema and inflammation in sheep. The facial eczema was allergic eczema caused by hepatic dysfunction and hepatonecrosis.

Comparison of a novel form of zinc with zinc oxide bolus licensed for prevention of facial eczema, and interaction with copper oxide in sheep.

To evaluate a novel elemental zinc bolus compared with a registered positive control zinc oxide bolus and assess serum zinc concentrations following concomitant treatment with a capsule containing copper oxide needles. Forty Romney-cross ewes were randomly allocated in a 2 × 2 factorial design study. On Day 0, 20 ewes received novel boluses containing elemental zinc (Investigational Veterinary Product, IVP) while 20 received a zinc oxide bolus (control; CP). Half the animals in each zinc treatment group (n = 10) were treated with a copper oxide needle capsule [Copasure® - Ewe]. Weekly, from Day -7 to 56, all ewes were assessed for signs of photosensitization, and for 10 ewes from each zinc treatment groups, samples were collected for analysis of serum GGT activity, serum zinc concentrations, faecal zinc concentrations and on Days -7 and 56, liver copper concentrations. Multivariable random-effects models assessed the effects of zinc treatment, copper treatment, treatment interactions and time on all analytes. Regression models examined associations between serum and faecal zinc concentrations and GGT activity. Low spore numbers indicated low Pithomyces chartarum challenge. Serum zinc levels were significantly higher in the IVP than in the CP group [p < 0.0001] and varied by time [p < 0.001] and positively associated with faecal zinc concentration [p < 0.001]. Copper treatment did not affect serum zinc [p = 0.82] or faecal zinc [p = 0.92] concentrations. Liver copper concentrations did not differ between zinc treatment groups on Day -7 [p = 0.6] or Day 56 [p = 0.95]. Only the CP/no copper group had no increase in liver copper concentrations.

Quantification of zinc concentrations in serum, milk and faeces of dairy cattle as a measure of effective zinc supplementation for management of facial eczema.

AIMS: To investigate the relationship between Zn concentrations in serum and those in milk or faeces, and to assess the ability of the Zn concentrations in milk, serum and faeces to predict intake of ZnO in dairy cattle. METHOD: Seventy cows from one commercial farm in the Waikato region of New Zealand received one of seven dose rates (0, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 g/100 kg bodyweight (BW)) of ZnO given by oral drench, every morning, for 7 consecutive days. Every afternoon, milk and blood samples were collected from all cows. Free-catch faecal samples were collected during the afternoon milking on 3 days throughout the trial.Linear mixed models were used to assess the relationship between the concentration of Zn in serum and that in milk, and in faeces, respectively, and the relationship between dose rate of ZnO and concentrations of Zn in serum, faeces and milk, respectively. Receiver operating characteristic curve analysis was used to determine the ability of the Zn concentration in serum, milk and faeces to predict that a cow had been treated with a dose of ZnO ≥2.5 g/100 kg, the industry-recommended dose rate needed to protect against facial eczema. RESULTS: A 1-µmol/L increase in Zn concentration in milk was associated with a 0.14 (95% CI = 0.11-0.17) µmol/L increase in Zn concentration in serum. Zn concentration in faeces was scaled by its SD; a 1 SD increase was associated with a 1.83 (95% CI = 0.54-3.12) µmol/L increase in zinc concentration in serum. Zn concentrations in serum and faeces increased with increasing dose rates of ZnO. No differences in Zn concentrations in milk were noted between animals dosed with 1.5-3.5 g ZnO/100 kg BW, inclusive. At the optimal threshold of Zn concentration in serum to predict protective ZnO intake (22 µmol/L), the sensitivity was 0.76 (95% CI = 0.69-0.82) and specificity 0.85 (95% CI = 0.80-0.89). For the concentration of Zn in faeces, the optimal threshold was 17.36 mmol/kg, with a corresponding sensitivity of 0.84 (95% CI = 0.84-0.85) and specificity of 0.85 (95% CI = 0.73-0.94). At the optimal threshold for the Zn concentration in milk (76.6 µmol/L), the sensitivity was lower than the other two sample types at 0.59 (95% CI = 0.52-0.67), but with a similar specificity of 0.84 (95% CI = 0.79-0.88). CONCLUSIONS AND CLINICAL RELEVANCE: The concentration of Zn in milk shows promise as an initial screening test to identify dairy farms that do not provide adequate zinc to provide protection against FE.

Diagnosing subclinical facial eczema in cattle: does combining liver enzyme tests increase the accuracy of diagnosis?

AIMS: To assess whether adding glutamate dehydrogenase (GDH) activity measurements to measurements of gamma-glutamyl transferase (GGT) activity appreciably increases the accuracy of diagnosis of subclinical facial eczema (FE) in cattle. METHODS: As part of a larger study on the impact of FE on productivity, GGT and GDH activities were measured in serum samples collected from 426 cattle from one dairy farm in the Taranaki region in April 2018. Bayesian latent class analysis was then used to estimate herd prevalence of subclinical FE as well as the specificity and sensitivity of the activity in serum of GGT or GDH alone, and of GGT and GDH activities combined, as diagnostic tests for subclinical FE. RESULTS: The latent class analysis estimated the true prevalence of subclinical FE in the study population as 47.5 (95% probability interval (PI) = 38.3-55.3)%. There was no evidence of any clinically relevant difference between GGT and GDH activities as predictors of subclinical FE; the difference between the areas under the receiver operating characteristic curves for the two measures was 0.005 (95% PI = -0.02 to -0.03). Using the two tests in parallel, with a threshold of 50 IU/L for GGT and 225 IU/L for GDH resulted in specificity and sensitivity of >95%, markedly increasing the accuracy of diagnosis of subclinical FE compared to using GGT or GDH alone at any threshold. CONCLUSIONS AND CLINICAL RELEVANCE: In this herd, combining the two tests resulted in a clinically relevant improvement in the accuracy of diagnosis of subclinical FE compared to using either test alone, which if used at the individual level will result in fewer cattle being assigned the wrong FE status. This will also apply at the herd level, with combined testing producing fewer false-positive herd test results than using one enzyme alone. This is particularly important for monitoring the efficacy of FE control measures when the expectation should be that the proportion of cattle with FE is very low.

An observational study on the relationship between zinc concentrations in bulk tank milk and in serum and farmer-reported zinc supplementation of dairy cattle for facial eczema prophylaxis.

AIMS: To describe the concentration of Zn in bulk tank milk (BTM) in a sample of New Zealand dairy farms, investigate the association between the method of Zn administration for facial eczema prophylaxis and Zn concentrations in BTM and investigate the relationship between the concentration of Zn in serum and that in BTM. METHODS: Multiple BTM samples (n = 3,330) collected during milk pick-up by the milk tanker driver were stored and tested for 121 farms, in Northland (n = 50), Waikato (n = 51) and Southland (n = 20) from February to May 2017. Enrolled farms provided retrospective information on the type of Zn supplementation (if any) used for the prevention of facial eczema and the timeframe over which supplementation occurred. In addition, the concentration of Zn in serum was measured in blood samples collected from ≥15 cattle per farm for 22 farms from Northland (n = 11) and Waikato (n = 11), and compared against the concentrations of Zn in BTM on the day of blood sampling. A linear mixed model was used to model log Zn concentrations in BTM using method of Zn supplementation, region, milk fat and protein percentage, volume of milk, and frequency of milk pick-up as risk factors. A mixed logistic regression model was used to assess the relationship between Zn concentrations in BTM and the presence of cows with a concentration of Zn in serum of ≥20 µmol/L. RESULTS: The median Zn concentration in BTM was 67.9 (min 38.9, max 146.6) µmol/L. The median range of Zn concentrations for repeated samples of BTM within farm was 22.6 µmol/L. In comparison to farms that did not use any form of Zn supplementation, farms that supplemented Zn through a slow-release capsule, oral drench, in feed or a combination of in-feed and water were associated with increased concentrations of Zn in BTM (p < 0.001). There was no difference in Zn concentrations in BTM between farms that administered Zn through the water only and farms that did not administer Zn (p = 0.22). Every 15.3 µmol/L increase in Zn concentration in BTM was associated with 2.2 times (95% CI=1.7-2.9) the odds of a cow having Zn concentration in serum ≥20 µmol/L. CONCLUSION AND CLINICAL RELEVANCE: Zn concentration in BTM is highly variable between farms, days and Zn administration method. Zn concentration in BTM content has modest potential as a way to signal whether a herd has achieved the high Zn status considered to be protective against FE.

Ocular abnormalities in the Icelandic horse with a focus on equine recurrent uveitis: 112 Icelandic horses living in Denmark and 26 Icelandic horses living in the United States.

PURPOSE: To describe the most common ocular abnormalities in the Icelandic horse with focus on equine recurrent uveitis (ERU) and association between ocular abnormalities and summer eczema and coat colors. METHODS: A descriptive cross-sectional study. A complete physical and ophthalmic examination as well as measurement of serum titers for Leptospira serovariants was performed on Icelandic horses from Denmark (DK) and the United States (USA). RESULTS: One hundred and twelve Icelandic horses living in DK and 26 Icelandic horses living in the United States were included in this study (total of 138 horses, 274 eyes). The three most common ocular abnormalities were follicular conjunctivitis (55.8%, 153/274 eyes), cataracts (27.4%, 75/274 eyes), and multifocal chorioretinopathy ("bullet holes"; 19%, 52/274 eyes). The prevalence for ERU among Icelandic horses aged "eight years and older" was 8% (6/75 horses). The "insidious ERU" type was found in 83% of the ERU cohort (5/6 horses), while "classic ERU" was found in 17% (1/6 horses). A correlation between ERU and cataracts was found in the population (p < .01). Leptospiral serology results were not associated with ERU in either DK or US-Icelandic horses (p = 1.00, p = 1.00, respectively). ERU was not associated with summer eczema (p = .49), and no coat colors were associated with the ocular abnormalities found in the Icelandic horse (all p-values > .05). CONCLUSION: Follicular conjunctivitis, cataracts, and multifocal chorioretinopathy were the three most common ocular abnormalities findings. Icelandic horses who were 8 years or older had an 8% prevalence for ERU. Summer eczema and coat color were not associated with evidence of ERU or other ocular abnormalities.

Genomic Tools for the Identification of Loci Associated with Facial Eczema in New Zealand Sheep.

Facial eczema (FE) is a significant metabolic disease that affects New Zealand ruminants. Ingestion of the mycotoxin sporidesmin leads to liver and bile duct damage, which can result in photosensitisation, reduced productivity and death. Strategies used to manage the incidence and severity of the disease include breeding. In sheep, there is considerable genetic variation in the response to FE. A commercial testing program is available for ram breeders who aim to increase tolerance, determined by the concentration of the serum enzyme, gamma-glutamyltransferase 21 days after a measured sporidesmin challenge (GGT21). Genome-wide association studies were carried out to determine regions of the genome associated with GGT21. Two regions on chromosomes 15 and 24 are reported, which explain 5% and 1% of the phenotypic variance in the response to FE, respectively. The region on chromosome 15 contains the ß-globin locus. Of the significant SNPs in the region, one is a missense variant within the haemoglobin subunit ß (HBB) gene. Mass spectrometry of haemoglobin from animals with differing genotypes at this locus indicated that genotypes are associated with different forms of adult ß-globin. Haemoglobin haplotypes have previously been associated with variation in several health-related traits in sheep and warrant further investigation regarding their role in tolerance to FE in sheep. We show a strategic approach to the identification of regions of importance for commercial breeding programs with a combination of discovery, statistical and biological validation. This study highlights the power of using increased density genotyping for the identification of influential genomic regions, combined with subsequent inclusion on lower density genotyping platforms.

The prevalence of gross pathological damage in the livers of dairy cattle at processing plants in autumn in the North Island of New Zealand and an assessment of the gross liver pathology score as a method for estimating the prevalence of facial eczema.

AIM: To measure the prevalence of gross pathological damage in the livers of dairy cows at slaughter in the North Island of New Zealand in 2018 and 2019 and to determine, using Bayesian latent class analysis, the specificity and sensitivity of gross liver pathology score (GLS) as a method for detecting moderate to severe facial eczema (FE) at processing plants. METHOD: Meat inspectors at four processing plants located in the Northland, Waikato, Bay of Plenty and Taranaki regions of New Zealand graded all dairy cattle livers on particular days in April and May of 2018 and 2019 using a gross liver pathology score (GLS) from 0-5 (0 = no damage, 1= fatty liver, 2 = cholangitis and early cirrhosis, 3 = cirrhosis, 4 = extensive cirrhosis, 5 = regeneration). Forty livers from each grade were selected for histopathology. Sections from the apical margin of the right and the left lobes were scored using a histology biliary score (HBS; scored from 1-16) based on the classical histological lesions of FE focussing on changes that differentiate FE from fasciolosis. Mean HBS was collapsed into scores 2-6 (no and mild damage) and score 7-12 (moderate and severe) and GLS was collapsed into grades 0-2 (no or mild damage) and grades 3-5 (moderate, severe and chronic damage). A Bayesian latent class model was developed to estimate sensitivity and specificity of HBS and GLS. The diagnostic target was moderate or severe, gross and/or histological changes in the liver consistent with FE. RESULTS: A total of 2,899 dairy cow livers were graded at the four plants over the two study periods. There were 700/2,899 (24.1%) livers with at least some form of gross pathology damage (GLS≥1) and 130/2,899 (4.5%) livers with moderate, severe or chronic gross pathology damage (GLS≥3). The estimates (posterior median) for the sensitivity and specificity of GLS to liver damage were 0.844 (95% credible interval (CrI) = 0.757-0.905) and 0.932 (95% CrI = 0.866-0.973) respectively. Estimates for HBS were 0.834 (95% CrI = 0.765-0.892) and 0.778 (95% CrI = 0.707-0.854), respectively. CONCLUSION AND CLINICAL RELEVANCE: GLS is a useful means of estimating liver damage consistent with FE at slaughter. Increased use of liver scoring at slaughter could be useful for monitoring the likely impacts of FE at the country and regional levels.

Chronic facial eczema in sheep: description of gross and histological changes in the liver and association with serum gamma-glutamyltransferase activity at the time of sporidesmin intoxication.

AIMS: To determine the gross and histological changes developing in the liver of sheep 8 months after a single period of exposure to sporidesmin and to examine associations between the severity of gross and histological changes to the liver and the activity of gamma-glutamyltransferase (GGT) measured in serum in the sheep at the time of intoxication. METHODS: A group of 50 Romney ewes grazing a mixed ryegrass/white clover pasture were accidentally exposed to sporidesmin for up to 5 weeks. Seventeen sheep showed photosensitisation and four were subject to euthanasia. The remaining sheep were moved to safer pasture and a blood sample collected and analysed for serum GGT activity. The sheep were slaughtered 8 months later. Livers were classified into grossly normal, moderately affected, or severely affected and histology performed to assess portal fibrosis, biliary hyperplasia, portal inflammation, and hepatocellular necrosis. RESULTS: Serum GGT activity ranged from 59 to 1571 IU/L (reference range 32-70 IU/L). Thirteen of the 46 sheep developed clinical signs of facial eczema. However, at slaughter all except four sheep had grossly detectable changes to the shape of the liver including atrophy of the left lobe and the lateral part of the right lobe. Hypertrophy was typically limited to the medial part of the right lobe. In severely affected sheep the liver hypertrophy formed a nodular bulging mass. Changes in the liver shape were classified as severe in 25 and moderate in 17 sheep. Severely affected livers contained significantly more fibrosis than moderately affected livers (p = 0.001, Cliff's delta (d) = 0.68). While there was significantly greater fibrosis and biliary hyperplasia in the left than right lobes, histological changes were present throughout all samples taken of affected livers. Serum GGT activity taken during acute intoxication were correlated to subsequent fibrosis and biliary hyperplasia. CONCLUSIONS: Hepatic fibrosis develops in sheep after a single episode of sporidesmin intoxication, even in sheep with only mildly elevated GGT activity at the time of intoxication. Furthermore, the severity of the subsequent hepatic fibrosis was predicted by the degree of elevation of serum GGT activity during intoxication. CLINICAL RELEVANCE: More research is required to determine how the presence and severity of hepatic fibrosis affect animal production. However, if hepatic fibrosis does decrease production, the consistent development of fibrosis after sporidesmin ingestion reinforces the importance of avoiding exposure of livestock to sporidesmin. ABBREVIATIONS: GGT: Gamma-glutamyltransferase; d: Cliff's delta.

The cellular and molecular toxicity of sporidesmin.

The fungal metabolite sporidesmin is responsible for the hepatogenous photosensitising disease facial eczema in livestock. Toxicity is due to a sulfur-bridged epidithiodioxopiperazine ring that has wide biological reactivity. The ways in which the toxin causes hepatobiliary and other tissue damage have not been established. Hypotheses include direct interaction with cellular thiols including protein cysteine residues or production of reactive oxygen species resulting in oxidative stress. Comparison with the cellular effects of the structurally related compound gliotoxin suggests additional mechanisms including interaction with cell adhesion complexes and possible downstream consequences for regulated necrosis as a response to tissue injury. Revision of hypotheses of how sporidesmin affects cells has the potential to generate new strategies for control of facial eczema including through identification of proteins and genes that are associated with resistance to the disease.

Variability in measurement of Pithomyces chartarum spore counts.

AIMS To examine the agreement between spore counts of Pithomyces chartarum measured in a single aliquot of wash water with counts from multiple aliquots from the same 60 g pasture sample, and between spore counts measured in an individual 60 g pasture sample with counts from three 60 g pasture samples selected from the same 200 g paddock sample. MATERIALS AND METHODS Four Waikato dairy farms were visited once weekly from early January to late May 2013. One paddock, with 40 sampling sites, was selected per farm. At each visit, ∼200 g of pasture was collected per site. Spore counting was undertaken using a standard method, except that three separate 60 g pasture samples per 200 g paddock sample was counted; and for each 60 g pasture sample, spores were counted in 10 aliquots of wash water. The relationship between the results of a single aliquot and 6-10 aliquots of wash water from the same 60 g grass sample were assessed by calculating 95% prediction intervals. Limits of agreement analysis was used to assess the agreement between counts from one, two or three aliquots per 60 g pasture sample compared with 10 aliquots, and between counts from one and three 60 g pasture samples from the same 200 g paddock sample. RESULTS Comparing spore counts from individual aliquots with multiple aliquots resulted in large prediction intervals and 95% limits of agreement, which increased with increasing spore count. For an individual aliquot count of 2 spores, the 95% prediction interval for the count from 10 aliquots was 3-49 spores, and for an individual count of 10 spores the 95% prediction interval was 28-222 spores. Increasing the number of aliquots counted improved agreement. For a total count of 10 spores measured in 10 aliquots, the 95% limits of agreement, based on a single aliquot, were 2-50 spores, and for three aliquots were 5-20 spores. The agreement in spore counts measured in one compared with three 60 g pasture samples was moderate and also decreased with increasing spore count; the 95% limits of agreement were 4-14.5 for a mean spore count of 10. CONCLUSIONS AND CLINICAL RELEVANCE Measuring the spore counts of three aliquots of wash water per 60 g grass sample improved repeatability, and should be used as the standard technique, particularly when determining whether to start or finish facial eczema control programmes.

Variability in concentrations of zinc in serum and feed when using zinc oxide as a supplement for the prevention of facial eczema.

AIMS: To determine the variability of concentrations of Zn in feed, when used as a supplement to prevent facial eczema, and to determine the variability in concentrations of Zn in serum between cows and herds that are being supplemented with ZnO in feed, using in-shed feeders or on a feed pad. METHODS: Sixteen commercial dairy farms in the Waikato region of New Zealand were enrolled, that were supplementing cows with ZnO in the feed using either an automatic in-shed feeder (ASF) or a feed pad (FP) using a feed-out or mixer wagon. On each farm 10 cows were selected by the farmer, that were assumed to be representative of the age and liveweight of the herd. Four hours after supplement feeding, each cow was weighed and a blood sample collected for measurement of concentrations of Zn in serum. Three samples of feed were collected from each farm for Zn analysis, from the beginning, middle and end of the feed being distributed. Levene's test for homoscedasticity was used to analyse whether there were differences in variation of individual concentrations of Zn in serum, and in the feed, between the two feeding systems. Multivariable linear regression was used to examine associations between age, feeding method or liveweight and concentrations of Zn in serum, after accounting for the variability between farms. RESULTS: Of the 163 cows sampled, concentrations of Zn in serum were between 20-35 µmol/L in 75/163 (46 (95% CI=38-54)%) cows; were <20 µmol/L in 71/163 (44 (95% CI=36-52)%) cows, and >35 µmol/L in 17/163 (10 (95% CI=6-16)%) cows. The variation in concentrations of Zn in serum in individual cows differed between farms (p<0.001), and the variability was greater for cows fed using a FP than ASF (p<0.001). There was no difference in the variation of concentrations of Zn in feed between the two feeding methods (p=0.54), but concentrations of Zn in serum were associated with the amount of Zn offered in feed (p=0.008). CONCLUSIONS AND CLINICIAL RELEVENCE: There was significant variability between farms in the concentrations of Zn in the serum of cows being supplemented with ZnO in feed. Only 46% of cows sampled had concentrations of Zn between 20-35 µmol/L. Effective management of facial eczema should include monitoring Zn in the feed and in serum to ensure cows are receiving the correct dose they require.

Facial eczema management protocols used on dairy farms in the North Island of New Zealand and associated concentrations of zinc in serum.

AIMS: To describe and evaluate the current practices used to manage and prevent facial eczema (FE) in North Island dairy herds, and determine the within-herd prevalence of cows with elevated activities of gamma glutamyl transferase (GGT), and with concentrations of Zn in serum <18 µmol/L. METHODS: Between January and May 2014, 105 herd managers from throughout the North Island of New Zealand were invited to participate in the study when regional spore counts for Pithomyces chartarum started to rise towards 30,000 spores/g pasture. Managers selected 10 representative cattle that were weighed and blood-sampled by the herd veterinarian. Blood samples were analysed for concentrations of Zn in serum and GGT activity. Pasture samples were also collected and submitted for spore count estimation. Finally a survey of farm management practices relating to prevention of FE was completed by the herd manager. A mixed-effects logistic regression model was used to determine associations between herd-level and cow-level explanatory variables and the probability of a cow having a concentration of Zn in serum <18 µmol/L. RESULTS: Of the 1,071 cows tested, 79 (7.3 (95% CI=5.8-9.0)%) had GGT activity in serum >300 IU/L, and 35/106 (33 (95% CI=24.2-42.8)%) herds had ≥1 of the 10 cows sampled with GGT activity >300 IU/L. Of the 911 cows that were being treated with Zn, concentrations of Zn were between 18-35 µmol/L in 398 (43.6 (95% CI=40.4-46.9)%) cows, were >35 µmol/L in 32 (3.5 (95% CI=2.4-4.1)%) cows, and <18 µmol/L in 479 (52.6 (95% CI=49.3-55.9)%) cows. After adjusting for the confounding effect of region, the odds of a cow having concentrations of Zn in serum <18 µmol/L were 5.5 (95% CI=1.1-29) times greater for cows supplemented with zinc in water compared with those supplemented by drenching. Of the 105 herd managers, 103 (98%) stated that they had access to regional spore count data, but only 35/105 (33%) reported that they measured spore counts on their own farm. Overall, 98/105 (93%) managers reported that they had some form of FE management programme in place. Fungicides were used on their own or in combination with zinc treatments in 10 herds, ZnSO4 in water troughs was used in 68 herds, oral drenching with ZnO in nine herds, and ZnO supplied in-feed in 26 herds. Estimated daily dose rates of zinc were less than that required to treat a 400 kg cow on 42/68 farms that administered ZnSO4 in the water or ZnO as a drench. CONCLUSION AND CLINICAL RELEVANCE: This study has shown that FE management on dairy farms in the North Island of New Zealand could be substantially improved. It is likely that improved FE management would occur if herd managers were provided with more feedback on the success (or otherwise) of their FE management programmes.

Towards genomic selection for facial eczema disease tolerance in the New Zealand sheep industry.

Pithomycotoxicosis, more commonly known as facial eczema (FE), is a liver disease that occurs predominantly in New Zealand because of its toxigenic Pithomyces chartarum strains. The first reported case was in sheep in 1887. Since the 1930s, a number of studies have been conducted in an attempt to mitigate the problems FE has on the sheep and dairy industries. The research in these studies included work on fungicide and biological control of the saprophytic fungus, use of different pasture plants to inhibit fungal growth, stock management with respect to pasture fungal spore counts and the use of zinc prophylaxis on animals. The finding that there was a genetic basis in FE sensitivity in sheep prompted research for a genetic approach to mitigation in the form of a diagnostic DNA test for susceptibility to the disease. Recently, we have used the Illumina OvineSNP50 BeadChip to develop a genome-enabled prediction approach to screen for FE-tolerant sheep. Our current best genomic prediction for FE is for the Romney breed and has an accuracy of 0.38. This prediction accuracy is not as high as the individual accuracy gained by an artificial challenge test (0.64). However, it has the advantage of being a non-invasive test and can be provided as part of genomic testing for other traits at minimal cost.

Identifying chromosomal selection-sweep regions in facial eczema selection-line animals using an ovine 50K-SNP array.

Facial eczema (FE) is a hepato-mycotoxicosis found mainly in New Zealand sheep and cattle. When genetics was found to be a factor in FE susceptibility, resistant and susceptible selection lines of Romney sheep were established to enable further investigations of this disease trait. Using the Illumina OvineSNP50 BeadChip, we conducted a selection-sweep experiment on these FE genetic lines. Two analytical methods were used to detect selection signals, namely the Peddrift test (Dodds & McEwan, 1997) and fixation index FST (Weir & Hill, 2002). Of 50 975 single nucleotide polymorphism (SNP) markers tested, there were three that showed highly significant allele frequency differences between the resistant and susceptible animals (Peddrift nominal P < 0.000001). These SNP loci are located on chromosomes OAR1, OAR11 and OAR12 that coincide precisely with the three highest genomic FST peaks. In addition, there are nine less significant Peddrift SNPs (nominal P ≤ 0.000009) on OAR6 (n = 2), OAR9 (n = 2), OAR12, OAR19 (n = 2), OAR24 and OAR26. In smoothed FST (five-SNP moving average) plots, the five most prominent peaks are on OAR1, OAR6, OAR7, OAR13 and OAR19. Although these smoothed FST peaks do not coincide with the three most significant Peddrift SNP loci, two (on OAR6 and OAR19) overlap with the set of less significant Peddrift SNPs above. Of these 12 Peddrift SNPs and five smoothed FST regions, none is close to the FE candidate genes catalase and ABCG2; however, two on OAR1 and one on OAR13 fall within suggestive quantitative trait locus regions identified in a previous genome screen experiment. The present studies indicated that there are at least eight genomic regions that underwent a selection sweep in the FE lines.

Bile duct lesions associated with turnip (Brassica rapa) photosensitization compared with those due to sporidesmin toxicosis in dairy cows.

Cattle grazing turnips or other brassica forage crops occasionally develop hepatogenous photosensitization. In New Zealand, cases of bovine photosensitization associated with such crops frequently occur during late summer and fall, and this coincides with the facial eczema (sporidesmin toxicosis) "season." Clinical chemistry findings in acute photosensitization cases associated with both brassica and facial eczema include marked serum elevations in γ-glutamyl transferase and glutamate dehydrogenase activities. Distinctive bile duct lesions of "subacute" turnip photosensitization in 2 cows, comprising microscopic cholangiectasis with concentric periductal fibrosis of small bile ducts, and a spectrum of changes from bile duct necrosis progressing to obliterative sclerosis are described. These bile duct lesions are compared with those in 3 cases of "subacute" facial eczema in adult cows, where medium-sized and larger ducts tend to be involved and bile duct hyperplasia and portal fibrosis are more prominent, often leading to bridging between neighboring portal triads.

Phospholipids in sera of horses with summer eczema: lipid analysis of the autoserum preparation used in therapy.

REASONS FOR PERFORMING STUDY: Equine summer eczema, also known as insect bite hypersensitivity, affects horses recurrently during summer months. The treatment of this allergic pruritus is difficult and therefore there is a need for efficacious treatments. Autoserum therapy, based on the use of autogenous serum that is specifically prepared for oral administration and given when the animal shows clinical signs has been introduced recently. Lipids are thought to be responsible for the effect of this therapy. OBJECTIVES: The main aim of this study was to analyse the phospholipid content of autogenous serum preparations and to further assess whether these preparations have different lipid profiles depending on the clinical status of the horse. The hypothesis is that the major serum phospholipids typical of the horse are present in the autoserum preparation. STUDY DESIGN: Descriptive controlled clinical study. METHODS: Sera were collected from 10 affected and 6 healthy horses, prepared in a similar fashion and the lipids contained in the resulting autoserum preparations were analysed by electrospray ionisation mass spectrometry. RESULTS: The major phospholipid classes detected were phosphatidylcholine, sphingomyelin, phosphatidic acid and traces of lysophosphatidylcholine. Horses with summer eczema had significantly abundant concentrations of phosphatidylcholine (P = 0.042) and sphingomyelin (P = 0.0017) in comparison with healthy horses, while the concentration of phosphatidic acid was significantly higher in healthy horses (P = 0.0075). CONCLUSIONS: The autoserum preparation contains minute amounts of the main serum phospholipids in differing concentrations in healthy horses and horses with an allergic skin disease.

Dermatite associada ao consumo de farelo de arroz desengordurado em bovinos / Dermatitis associated with consumption of defatted rice bran in cattle

Dermatite tem sido observada em bovinos no Uruguai e no Rio Grande do Sul que são suplementados com farelo de arroz desengordurado em quantidade equivalente a 1% do peso corporal. Descreve-se um surto de dermatite associada ao consumo de farelo de arroz desengordurado em um município do interior do Rio Grande do Sul. Do total de 26 bovinos, com três anos de idade, sete apresentaram lesões que foram observadas após 24 dias de ingestão da ração de farelo de arroz desengordurado. As lesões eram observadas na extremidade distal dos membros posteriores e se caracterizavam por áreas de alopecia, com acentuado espessamento da epiderme, formando crostas secas, espessas e fissuradas. A lesão histológica observada nestes casos foi caracterizada como dermatite perivascular superficial crônica focalmente extensa moderada, com acantose irregular e formação de crosta serocelular. As lesões macro e microscópicas observadas, juntamente com os dados epidemiológicos, permitem concluir o diagnóstico de dermatite associada ao consumo de farelo de arroz desengordurado. As lesões histológicas, embora não patognomônicas, são descritas nesta doença.

Dermatitis has been observed in Uruguay and Rio Grande do Sul, in cattle supplemented with defatted rice bran in an amounts equivalent to 1% of body weight. An outbreak of dermatitis in cattle associated with consumption of defatted rice bran in Rio Grande do Sul, is herein described. Out of a total of 26 3-year-old cattle consuming this ration, seven had lesions that were observed after 24 days on the ration. The lesions were observed in the distal hind limbs and were characterized by areas of alopecia with marked thickening of the epidermis with crust formation imparting a thicken and fissured aspect to the skin. The histological lesions observed in these cases were characterized as moderate superficial perivascular chronic dermatitis focally extensive, with irregular acanthosis and serocellular crusting. The gross lesions observed, together with epidemiological data, allow for a diagnosis of dermatitis associated with the consumption of defatted rice bran. Histologic changes, although not pathognomonic, are typically described in this disease.