Longitudinal study of the effect of sporidesmin toxicity on lamb production and serum biochemistry in a flock of 46 Romney ewes using a standardised measure of liver damage.

AIMS: To evaluate the effect of sporidesmin toxicity on production outcomes and serum biochemistry analytes in mixed age Romney ewes, using a standardised measure of liver damage. METHODS: This was a prospective longitudinal study following 46 mixed age Romney ewes from sporidesmin intoxication in April 2019, to slaughter 8 months later. The ewes were blood-sampled up to eight times, with a panel of serum biochemistry tests performed on the final six samples. However, only gamma-glutamyl transferase (GGT) activity was measured in the first two samples collected at the end of sporidesmin intoxication and 2 weeks later. Body condition score, ewe weight and production data were also recorded. Using a standardised liver score, based on histology of liver samples collected at slaughter, ewes were assigned to one of three liver disease categories (LDC); low, middle, and high. These were then used as the outcome or predictor variables for statistical analyses. Finally, two separate decision tree models, using recursive partitioning (RP), were fitted to the biochemistry data and to the GGT data collected at FE outbreak, to predict ewes in the low LDC. RESULTS: There was no evidence of a difference for the effect of LDC on ewe weight (p = 0.86) with ewes, on average, gaining weight to weaning. Weaning percent, lamb rearing percent and ewe flock efficiency were lower in ewes with high LDC, and scanning-to-weaning lamb loss was significantly higher in sheep with high LDC (p = 0.02). Serum activities of GGT and glutamate dehydrogenase and concentration of globulin were significantly lower in sheep with low LDC than in sheep with middle or high LDC (p < 0.05). However, there was no evidence of a difference for the effect of LDC on other biochemistry variables (p > 0.05). The final RP model for the biochemistry data categorised ewes as low LDC if their GGT was <122 IU/L, 3 months after sporidesmin intoxication, or if their GGT was <514 IU/L, <18 days after sporidesmin intoxication. CONCLUSIONS AND CLINICAL RELEVANCE: Sheep with gross and histological evidence of severe sporidesmin-induced liver damage were able to maintain or gain body weight, suggesting that sporidesmin intoxication alone is not causative of poor body condition. Similarly, many of the serum biochemistry tests were not associated with evidence of liver damage. Lamb production was reduced in ewes with evidence of severe liver damage and the decision tree model showed promise as a basis to select ewes for culling.

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.

Anal fibropapillomas containing bovine papillomavirus type 2 DNA in two groups of heifers.

CASE HISTORY Anal warts were observed in heifers in two unrelated groups of animals. Heifers in one group developed visible warts 4 months after manual rectal examination and heifers in the other group developed warts 5 months after examination using a hand-held rectal ultrasound probe. CLINICAL FINDINGS Large exophytic proliferative anal masses were observed in 5/15 (33%) heifers in one group and 13/149 (9%) heifers in the second group. Heifers in the second group were also noted to have similar masses on the underside of the tail at sites previously used for venepuncture and some of the heifers had skin warts. Despite the large size of the anal masses, none of the heifers showed clinical signs of systemic illness. HISTOPATHOLOGICAL FINDINGS An anal mass was removed from one heifer in each of the two groups. Sections from both masses showed hyperplastic epithelium covering a proliferation of well-differentiated fibroblasts consistent with fibropapillomas. Small numbers of cells within the epidermis had clear cytoplasm with clumped keratohyalin granules. MOLECULAR BIOLOGY Bovine papillomavirus (BPV) type 2 DNA was amplified from both fibropapillomas by PCR. DIAGNOSIS Multiple anal fibropapillomas associated with BPV-2. CLINICAL RELEVANCE Bovine anal fibropapillomas have only been reported in heifers that have undergone rectal examination, and infection of anal microabrasions in an immunologically naïve animal appears to be associated with disease development. The source and method of spread of BPV-2 within these groups could not be determined. However spread of BPV-2 within the groups by the veterinarian performing rectal examinations may have been most likely. While these fibropapillomas had a dramatic appearance, like fibropapillomas elsewhere on the body, they did not have any significant effect on the health of the affected heifers. As these lesions can be diagnosed by clinical examination and self-resolve without treatment, it is important that veterinarians are aware of this rare manifestation of papillomavirus infection of cattle.

Multiple viral plaques with sebaceous differentiation associated with an unclassified papillomavirus type in a cat.

CASE HISTORY AND CLINICAL FINDINGS A 15-year-old neutered male domestic short-haired cat was presented due to multiple 0.5-2 cm-diameter crusting plaques in the left preauricular region, over the bridge of nose, and in the right periocular region. The plaques did not appear to cause discomfort. HISTOPATHOLOGICAL FINDINGS Biopsy samples of four plaques were examined histologically. Three plaques consisted of well-demarcated foci of mild epidermal hyperplasia overlying markedly hyperplastic sebaceous glands. Approximately 60% of the hyperplastic cells contained a large cytoplasmic vacuole that ranged from being clear to containing prominent grey-blue fibrillar material. The fourth plaque was composed solely of epidermal hyperplasia, consistent with previous descriptions of feline viral plaques. MOLECULAR BIOLOGY Papillomavirus DNA was amplified from all four plaques using PCR. A single DNA sequence was amplified from the plaques with sebaceous differentiation. This sequence was identical to the FdPV-MY sequence previously suggested to be from a putative unclassified papillomavirus type. Felis catus papillomavirus type 2 sequences were amplified from the plaque typical of feline viral plaques. Immunohistochemistry to detect p16CDKN2A protein (p16) showed marked immunostaining throughout the hyperplastic epidermis and adnexal structures within the plaques with sebaceous differentiation. DIAGNOSIS Multiple feline viral plaques with variable sebaceous differentiation. CLINICAL RELEVANCE Feline viral plaques with sebaceous differentiation have not been previously reported in cats. The presence of unique cell changes within these lesions, the detection of an unclassified papillomavirus type, and the p16 immunostaining within these plaques suggest that they may have been caused by the papillomavirus that contains the FdPV-MY sequence.

The use of quantitative PCR to detect Felis catus papillomavirus type 2 DNA from a high proportion of queens and their kittens.

Squamous cell carcinomas are common feline skin cancers that have been associated with infection with Felis catus papillomavirus type 2 (FcaPV-2). Currently, little is known about the epidemiology of FcaPV-2 infection. The aim of this study was to develop a real-time PCR assay to quantify FcaPV-2 DNA in plucked hairs and skin swabs from 11 healthy breeding queens and their kittens. Samples were taken prior to kittening and then 2, 7 and 28 days after kittening to determine the age at which the kittens were first exposed to the virus. FcaPV-2 DNA was amplified from all of the queens and from 91% of the kittens at 2 days of age. There was a wide range in the quantity of FcaPV-2 DNA detected, from 1 to 92,520 copies per swab, and from 0.01 to 234 copies per copy of reference gene DNA in the hair plucks. The quantity of FcaPV-2 DNA detected in samples collected from the kittens was strongly correlated to that of their respective queens and the mean viral DNA load was similar for cats within a household but varied significantly between households. This is the first time that quantitative PCR has been used to detect FcaPV-2 DNA and the results suggest that the virus is ubiquitous but there is a wide variation of viral DNA loads. Kittens appear to be exposed to FcaPV-2 early in life, presumably from direct contact with their queen. These results are important when determining if FcaPV-2 infection of cats is preventable.

Effects of a supplement containing trans-10, cis-12 conjugated linoleic acid on bioenergetic and milk production parameters in grazing dairy cows offered ad libitum or restricted pasture.

Conjugated linoleic acid (CLA) reduces milk fat synthesis in grazing dairy cows and may improve calculated net energy balance (EBAL). Study objectives were to determine whether CLA-induced milk fat depression could be utilized during times of feed restriction to improve bioenergetic and milk production parameters. Twelve multiparous rumen-fistulated Holstein cows (204 +/- 7 d in milk) were offered ad libitum (AL) or restricted (R) pasture and abomasally infused twice daily with 0 (control) or 50 g/d of CLA (CLA; mixed isomers) in a 2-period crossover design. Treatment periods lasted 10 d and were separated by a 10-d washout period. Milk and plasma samples were averaged from d 9 and 10, and EBAL was calculated from d 6 to 10 of the infusion period. Pasture restriction reduced the yield of milk (3.9 kg/d) and milk components. The CLA treatment reduced milk fat yield by 44 and 46% in AL and R, respectively. There was no effect of CLA on milk yield or milk lactose content or yield in either feeding regimen; however, CLA increased the milk protein content and yield by 7 and 6% and by 5 and 8%, in AL and R, respectively. The CLA-induced changes to milk fat and protein doubled the protein:fat ratio in both AL and R. Calculated EBAL improved following the CLA infusion (-0.44 vs. 2.68 and 0.38 vs. 3.29 Mcal/d for AL and R, respectively); however, CLA did not alter plasma bioenergetic markers. Data indicate that during short periods of nutrient limitation, supplemental CLA may be an alternative management tool to enhance protein synthesis and improve the milk protein:fat ratio and calculated EBAL in cows grazing pasture. Further studies are required to determine whether CLA is effective at improving bioenergetic and production parameters during more severe or longer term nutrient restriction.

Endogenous synthesis of cis-9, trans-11 conjugated linoleic acid in dairy cows fed fresh pasture.

New Zealand Holstein-Friesian cows (n = 4) were used to quantify the importance of endogenous synthesis of cis-9, trans-11 conjugated linoleic acid (CLA) via Delta(9)-desaturase in cows fed a fresh pasture diet. The experiment was a 4 x 4 Latin square design with treatments arranged in a 2 x 2 factorial. Treatments lasted 4 d and were pasture only, pasture plus sterculic oil, pasture plus sunflower oil, and pasture plus sunflower oil plus sterculic oil. Abomasal infusion of sterculic oil inhibited Delta(9)-desaturase and decreased the concentration of cis-9, trans-11 CLA in milk fat by 70%. Using the changes in cis-9 10:1, cis-9 12:1 and cis-9 14:1 to correct for incomplete inhibition of Delta(9)-desaturase, a minimum estimate of 91% of cis-9, trans-11 CLA in milk fat was produced endogenously in cows fed fresh pasture. Dietary supplementation of a pasture diet with sunflower oil increased the proportion of long chain fatty acids in milk fat; however, the increase in vaccenic acid concentration was small (18%) and there was no increase in cis-9, trans-11 CLA concentration. Overall, results show that endogenous synthesis is responsible for more than 91% of the cis-9, trans-11 CLA secreted in milk fat of cows fed fresh pasture. However, the failure of plant oil supplements to increase the concentration of cis-9, trans-11 CLA in milk fat from pasture-fed cows requires further investigation.

Effects of pasture allowance on the yield and composition of milk from cows of different beta-lactoglobulin phenotypes.

The objective of this study was to determine whether the differences in the composition of milk from cows of different beta-lactoglobulin beta-LG) phenotypes are affected by the amount of pasture available and, hence, pasture dry matter intake. Twenty-two Friesian cows of each of the AA and BB variants of the beta-LG phenotype were subjected to ad libitum grazing or restricted grazing in crossover experiments during spring (early lactation, approximately 60 d in milk) and summer (mid to late lactation, approximately 180 d in milk). Milk samples were collected from each cow at the end of each 8-d treatment period and analyzed for composition. Cows of the AA variant of the beta-LG phenotype had higher concentrations of whey protein and beta-LG, but lower concentrations of casein (CN), alpha-CN, kappa-CN (summer only), and BSA, than cows of the BB variant. Compared with cows with a restricted allowance, cows grazing ad libitum had higher milk yields and concentrations of protein, casein, whey protein, and all individual proteins except BSA and immunoglobulin. There were no interactions between effects of pasture allowance and phenotype on milk yield or composition. The data show that having adequate pasture for grazing cows is important not only to maximize milk yield, but also to optimize concentrations of protein and casein, and hence the manufacturing potential of milk. Further, the differences in composition of milk from cows of differing beta-LG phenotypes persisted during short-term restrictions in pasture allowance, and between spring and summer.

Seasonal and lactational influences on bovine milk composition in New Zealand.

This study was designed to evaluate the respective influences of stage of lactation (SOL) and time of year on the seasonal variation in milk composition for pasture-fed dairy cows in New Zealand. Four herds of approximately 20 Friesian cows were used, one herd calving in a 6 week period beginning in each of January, April, July and October. Cows grazed rye-grass-white clover pasture only, except during June when all cows received supplementary pasture silage. Milk samples were collected from each cow in milk on four occasions during the year (September, December, March and June), to give a total of three samples per cow (early, mid and late lactation; about 30, 120 and 210 d respectively after calving). Samples were analysed for a detailed range of components. Concentrations of many milk components (e.g. total protein, fat, casein and whey protein) increased as lactation progressed; the extent of these increases depended on the time of year. These results indicated that spreading calving throughout the year would lessen seasonal variations in the gross composition of mill supplied to factories, leading to a more even distribution of product yield across the year. Despite this, variations in some important manufacturing properties were affected by time of year but not by SOL. Ratios of protein: fat and casein: whey protein were not significantly affected by SOL, but were affected by time of year. The solid fat content of milk was also affected by time of year. Seasonal variations in the manufacturing properties of milk may be reduced but not eliminated by changing the time of calving.

Does endorsement of the disease concept of alcoholism predict humanitarian attitudes to alcoholics?

It has been widely assumed that the disease concept of alcoholism is a powerful vehicle for the promotion of humanitarian attitudes to alcoholics. However, Crawford and Heather have argued that individual differences in attitudes to alcoholics are liable to be a reflection of broader attitudes to deviancy rather than a function of endorsement/rejection of a disease conception. This argument was subjected to empirical scrutiny by means of a questionnaire distributed to 200 members of the public. The questionnaire (1) measured attitudes to four deviant groups--alcoholics, drug addicts, compulsive gamblers, and juvenile delinquents--and (2) recorded whether respondents endorsed or rejected a disease conception of these deviant conditions. Attitudes to the non-alcoholic deviant groups were better predictors of humanitarian attitudes to alcoholics than was endorsement of a disease conception of alcoholism.