Immunohistochemical demonstration of connexin-related epithelization defects in a lamb caused by (erythro)keratodermia variabilis

The distribution of four important connexins (Cx 26, 30, 31, 43) in the skin of a neonatal lamb with (erythro)keratodermia (EKV) was demonstrated using immunohistochemistry, including a very sensitive visualization system. The reaction staining for Cx 26, 30 and 31 was negative to weak in all skin structures, and only Cx 43 displayed weak to moderate positive reactions, although not uniformly distributed throughout the important systems (e.g. epidermis, hair follicle sheaths). Thus, the study proves for the first time that connexin defects are associated with the development of EKV in domesticated mammals, as they are in humans.     

Alternative cell lines for the propagation of lumpy skin disease virus

In our Institute lumpy skin disease virus is grown on primary lamb testis cells for isolation, identification and vaccine production. However, the availability of lambs in Kenya has been seriously reduced over the past few years. This has led to an increase in the cost of using primary lamb testis cells. This study was undertaken to investigate other primary cell lines, which are easily available and provide an equivalent or better yield of lumpy skin disease virus. Foetal bovine muscle (FBM) cells were found to be an adequate alternative for lamb testis cells.     

新生羔羊痢疾原因及防治

羔羊痢疾是新生羔羊群体中的常发病和高发病,属于急性毒血症和急性传染性疾病。临床上主要表现为剧烈腹泻,肠道严重溃烂。该种疾病主要危害7日龄内新生羔羊,随着年龄的增长,抵抗能力增强,羔羊痢疾的发生率呈现逐渐下降趋势。新生羔羊痢疾具有发病急、发病过程短、致死率高的特点,发生流行后如果不能及时诊断,及时采取措施进行防控,短时间内会造成大批量的羔羊死亡,给养殖场带来不可挽回的经济损失。该文主要论述新生羔羊痢疾的发病原因和防治措施,缩短发病周期,提高治疗效果。     

Evaluation of serum allergen-specific IgE for the diagnosis of food adverse reactions in the dog

A new monoclonal enzyme-linked immunoassay (ELISA; CMG IMMUNODOT, Fribourg, Switzerland) measuring food antigen-specific serum IgE was used in an attempt to investigate food allergen-specific IgE in dogs. The serum of eight dogs with clinically proven adverse reactions to specific proteins was tested for beef, cow's milk, pork, lamb, hen's egg, soybean, fish mix (cod/sole), peanut, maize and wheat flour. The control group consisted of three healthy dogs, three dogs with nonallergic skin disease, two dogs with atopy, a cat and a horse. Only three mild positive reactions to beef, lamb and peanut, respectively, were found in this study; the sera were from two control dogs with the clinical diagnosis of dermatophytosis and atopy. None of the animals with confirmed food adverse reactions showed positive reactions. This study indicates that the diagnosis of food adverse reactions in the dog by measuring allergen-specific IgE with the used mononuclear ELISA is unreliable.     

羔羊不同生长时期饲养管理

羔羊作为养殖场的重要生产资料,其成活率直接影响养殖场经济效益,因此需要采取科学合理的养殖方法,促进羔羊健康生长。羔羊出生后,由于各个脏器器官未全面生长发育,外界应激因素较多,一旦养殖管理不当,都会造成疾病发生。某些传染性疾病的发生流行会在短时间内传播到整个羔羊群体中,引发剧烈发病,造成大面积死亡,给养殖户带来不可挽回的经济损失。该文主要分析羔羊不同生长发育阶段的饲养管理技术要点。     

Food allergen-specific serum IgG and IgE before and after elimination diets in allergic dogs

Serum food allergen-specific antibody testing is widely offered to identify suitable ingredients for diets to diagnose adverse food reaction (AFR) in dogs with allergic skin disease. Antibody concentrations in blood samples obtained during an unsuccessful diet to help in the choice of diet changes may be influenced by the previous diet. The objective of this paper was to measure food antigen-specific IgE and IgG for the most commonly used 16 food antigens before and after an elimination diet. Levels of food-specific serum IgE and IgG antibodies were measured by enzyme-linked immunosorbent assay (ELISA). Dogs had detectable IgE antibodies to beef, pork, lamb and cows' milk; and detectable IgG antibodies to beef, pork, lamb, cows' milk, chicken and turkey. Of 19 dogs with complete data sets, 14 dogs showed clear improvement during diet and in 7 dogs AFR could be diagnosed by deterioration on rechallenge and subsequent improvement on refeeding the diet. Serum was obtained before and 6-8 weeks after beginning such a diet. There was no significant difference in pre- and post-diet levels for any of the individual allergens nor for the total IgE and IgG concentrations of all antigens (P=0.55 and P=0.53 respectively). In these 19 dogs in which an elimination diet was used for the diagnosis of food allergy and in which 14 were probably food allergic and 7 were proven food allergic there were no significant differences in food-specific antibodies before and after an elimination diet of 6-8 weeks.     

1例东福利生羔羊放线杆菌病的诊治

放线杆菌为动物黏膜共生菌,当口腔黏膜或皮肤出现创口时侵入机体,引起发病,呈散发流行,但也可由于饲养管理不当造成大量动物发病,为养殖业造成极大的损失。针对2019年春季发生于呼和浩特地区某羊场的羔羊放线杆菌感染病例的临床症状、病理变化、实验室检查及鉴别诊断方法进行详细介绍,并提出相应的防控措施,以供兽医人员和养殖户参考。     

Colibacillosis in neonatal lambs: onset of diarrheal disease and isolation and characterization of enterotoxigenic Escherichia coli from enteric and septicemic forms of the disease.

A lamb ligated intestinal segment (LIS) test was adapted to determine the enterotoxigenicity of Escherichia coli isolates obtained from fecal and blood specimens from neonatal lambs with overt diarrheal disease. The lamb LIS was distended by 28 of 80 (37%) isolates from fecal specimens from 23 affected lambs. Enterotoxigenic E coli isolations were made from 10 of the 23 lambs examined. Isolates of E coli were made from the blood of 17 of 76 (22%) animals with severe diarrheal disease. Distention of the lamb LIS was caused by 3 of 39 (7.7%) isolates from 2 of 17 lambs with E coli septicemia. All lambs (n = 266) that were born during a 4-day period in an intensified shed lambing operation and that were not given prophylactic antibiotic therapy developed diarrheal disease within 28 hours of birth. Signs of enteric disease appeared in lambs born during inclement weather in a significantly (P less than 0.001) shorter period than in those born during mild weather conditions.     

TRANSMISSION OF A MUCOSAL DISEASE VIRUS INFECTION BETWEEN SHEEP

The transmission of mucosal disease virus (MDV) from infected ewes and their lambs to susceptible sheep was investigated. MDV was recovered from the amniotic fluid of an infected pregnant ewe and from the blood, nasal swabs and urine of hairy lambs. MDV infection was transmitted either at lambing, from infective foetal fluids or lambs, or later as a result of contact with a surviving with a hairy lamb and either aborted or gave birth to an infected hairy lamb. Adult sheep and 12-months-old sheep were less readily infected than were newborn lambs. Pregnant ewes were infected by contact with a hairy lamb and either aborted or gave birth to an infected hairy lamb. A method to minimise spread of the infection in the field is suggested.     

A hereditary skin defect in sheep

Some years ago a lamb with abnormal skin was received at the State veterinary research station for small ruminants (SVRS), Stavanger, from a farm in Ryfylke. The lamb had apparently been normal at birth, but by normal activity and contact with its mother, extensive wounds developed, with large, loose skin areas. The lamb’s condition had deteriorated so much that it was killed when it was two days old. Two ewes sired by the same ram had given birth to similar lambs the same year, while some years earlier, lambs with the same defect had been born by other ewes in the flock.     

PrP genotype and lamb birth weight in a scrapie-free environment: Is there an association?

The National Scrapie Plan (NSP) for Great Britain includes selective breeding programmes. These aim to reduce the frequencies of the ovine prion protein (PrP) genotypes at high risk of developing clinical disease (principally those containing the VRQ allele) within the national flock, and select for the low-risk ARR-containing genotypes. The aim of this work was to use available data from embryo transfer programmes in guaranteed scrapie-free environments to investigate whether there was a difference in lamb birth weight associated with the lamb's PrP genotype, which might affect survival. The first analysis utilised data from 355 Cheviot lambs born between 2001 and 2004. The analysis was then repeated using a larger data set of 737 Cheviot, Dorset and Suffolk lambs born between 1999 and 2003. The most important determinants of mean lamb birth weight were litter size, sex and recipient ewe breed, plus lamb breed in the three breed analysis. In both analyses the effects of all these variables are consistent and of the same order of magnitude. In the first analysis there was evidence for an apparent increase in mean lamb birth weight for the ARR-containing genotypes of 0.3 kg (95% C.I. 0.1–0.5 kg). Whereas, in the second data set there was evidence for a decrease in mean lamb birth weight for the VRQ-containing genotypes of − 0.6 kg (95% C.I. − 0.8 to − 0.4 kg). This had been masked in the first analysis by the categorisation of these genotypes with the ARQ/ARQ genotype. Within these flocks, in a scrapie-free environment, neither finding provides support for concerns that selection for low risk ARR-containing genotypes would be detrimental to lamb birth weight, which is considered to be the most important determinant of lamb survival. Extension of this work into field flocks, where scrapie-status cannot be easily assured, will require the collection of sufficient data to adjust for known direct effects as well as any additional potential confounding effects.     

Efficacy of selamectin against experimentally induced tick (Rhipicephalus sanguineus and Dermacentor variabilis) infestations on dogs

Seven controlled studies were conducted to investigate the efficacy of selamectin against weekly infestations of dogs with Rhipicephalus sanguineus and Dermacentor variabilis. Treatments (selamectin or vehicle alone) were applied topically at weekly, 2-week, or monthly intervals or in a "Monthly Plus" regimen (monthly treatment with an additional treatment at 14 days after the first treatment). Selamectin was supplied in unit dose tubes designed to deliver a minimum dosage of 6mgkg(-1). The studies ranged in duration from 37 to 90 days. Fifty adult ticks (+/-2) were applied approximately weekly, and tick counts were performed 3, 4, and 5 days after each infestation. The efficacy of selamectin was expressed as the percentage reduction in geometric mean tick counts on selamectin-treated dogs compared with those for dogs treated with the vehicle alone (negative-control). In one study, the engorgement of Dermacentor variabilis was assessed by weighing ticks after removal on the fifth day after each infestation. Weekly and 2-week interval treatments with selamectin provided efficacies against R. sanguineus of >89% across the entire study periods, with 100% efficacy being achieved from 21 days after the first dose and thereafter (study duration, 37 days for the weekly regimen and 44 days for the 2-week interval regimen). D. variabilis also was well controlled by the 2-week interval treatment regimen, with >96% efficacy being achieved from 21 days after the first treatment and thereafter until the end of the study (study duration: 90 days). In five of six studies incorporating three treatments at monthly intervals, the percentage reduction in R. sanguineus and D. variabilis counts 5 days after infestation ranged from 90 to 100% in the second and third months after treatment began. In the sixth study, reductions of > or =95% in D. variabilis counts 5 days after infestation were achieved for 2 weeks after each treatment in the second and third months. For the Monthly Plus regimen, from the second treatment (day 14) onwards, selamectin achieved 83-100% reductions in R. sanguineus and D. variabilis counts 3 days after infestation, and 94-100% reductions 5 days after infestation in three of the four studies. In the fourth study, selamectin demonstrated good efficacy against D. variabilis for 2 weeks after each treatment. In all seven studies, the counts from the selamectin-treated dogs were significantly (P< or =0.018) lower than those from the vehicle-treated dogs on 77 of the 80 assessments made 5 days after infestation. Selamectin also significantly (P< or =0.0105) reduced engorgement of female D. variabilis. These studies demonstrated that selamectin, administered topically to the skin in a single spot at a minimum dosage of 6mgkg(-1) at monthly intervals, was effective in the control of experimentally induced R. sanguineus and D. variabilis infestations on dogs.     

Immunohistochemical detection of antigen in lamb tissues naturally infected with sheeppox virus

The present study describes the detection of sheeppox virus antigen in various lamb tissues, using an immunohistochemical technique, in sheeppox cases which occurred naturally. Sheeppox viral antigen was detected in the cytoplasm of sheeppox cells and degenerated epithelial cells of the skin, lungs and digestive tract involving typical sheeppox lesions. Nuclear staining was also observed in some typically deformed nuclei of sheeppox cells. The immunostaining of sheeppox virus showed a correlation with the presence of sheeppox cells and degenerated epithelial cells resembling them. Additionally, in order to confirm the presence of sheeppox virus in the skin and lung samples, direct electron microscopy was performed and sheeppox virus was only demonstrated in two skin samples.     

Ovine abortion and stillbirth due to purulent placentitis caused by Yersinia pseudotuberculosis

Yersinia pseudotuberculosis was isolated from an aborted placenta and stillborn lamb from a sheep flock having multiple abortions. Given intravenously, it caused elevated body temperatures and purulent placentitis in eight of nine ewes. Two ewes died following infection at 2.5 months of gestation. Two ewes infected at 3.5 months gestation aborted; three infected at four months gave birth to weak, premature, or moribund lambs. One ewe infected at 4.5 months gave birth to a healthy lamb. One lamb which died minutes after birth had focal necrotizing hepatitis, a lesion observed in a stillborn lamb during the original disease outbreak. Y. pseudotuberculosis was reisolated from endometrial, placental, and fetal lesions of experimentally infected animals.     

Isolation of border disease virus from twin lambs in Alberta

We describe herein a field case of border disease (BD) in twin lambs. Both lambs were unthrifty, stunted, and one exhibited nervous signs characteristic of BD, with tremors of the head, neck, hind legs, and pelvis. Hairiness of the coat and excessive pigmentation, often seen in lambs with BD, were not observed. A noncytopathic virus, which showed cross-reactivity with bovine viral diarrhea (BVD) virus antiserum and BVD virus monoclonal antibodies, was isolated repeatedly from leukocytes from one lamb and from tissues of the other. Although the source of the virus is unknown, our results suggest that the dam of the affected twins had been infected during pregnancy. We used the BD virus isolated to inoculate pregnant ewes and experimentally reproduce the disease in a newborn lamb. Our findings indicate that leukocytes, rather than serum, should be utilized for BD virus isolation. Further, it is recommended that BD virus, rather than BVD virus, be used in serum neutralization tests when screening sheep for antibody titers.     

绵羊痘的诊断

绵羊痘是由绵羊痘病毒引起绵羊的疾病,其特征为发热、全身皮肤痘疹,内脏(特别是肺脏)黏膜结节,是危害养羊业最为严重的传染病之一。该病经常引起绵羊的大批感染或死亡,病死率可达50%以上,羔羊可达100%,不仅给养羊业带来巨大的经济损失,还严重阻碍了养羊业的发展。文章针对2011年1月份新疆某地区部分养羊户饲养的卡拉库尔羊发生的羊痘疫情进行了流行病学调查、临床症状、病理变化观察和实验室诊断,结果确诊为绵羊痘。     

牛羊魏氏梭菌病的诊断及综合防治

由产气荚膜梭菌引起的牛羊魏氏梭菌病是一种急性传染病,常引起羊肠毒血症、羊猝狙、羔羊痢疾、牛猝死症等疾病,该病发病急、死亡快、死亡率高,给牛羊养殖业造成重大经济损失。对牛羊常见的魏氏梭菌病的诊断与综合防治措施进行综述,以期为牛羊魏氏梭菌病的防治提供参考。     

Acephalous lamb from an in vitro-produced sheep embryo

This is the first report of an acephalous lamb from the transfer of an in vitro-produced sheep embryo. Twelve in vitro-fertilized embryos were transferred to 4 recipient ewes (3 embryos/ewe). Two ewes remained pregnant: one delivered a normal female lamb, the other a male acephalous lamb. Possible contributing factors are discussed.