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Background: Pneumonia is the largest cause of mortality in Canadian lambs. Currently there are no licensed ovine vaccines in Canada to reduce economic losses from this production-limiting disease., Objective Animals and Procedure: The effectiveness of an experimental subunit Mannheimia haemolytica leukotoxin A (LtxA) and transferrin binding protein B (TbpB) vaccine was evaluated in lambs for reduction of clinical disease in an experimental challenge study and in a controlled randomized field trial in a large commercial sheep operation., Results: Following an experimental challenge of parainfluenza 3 virus and M. haemolytica , the subunit vaccine induced significantly higher LtxA and TbpB antibody titers at 48 d post-challenge compared to the adjuvant and Ovipast Plus bacterin (Merck Animal Health), but there were no significant differences in clinical signs or mortality among vaccine groups. Following vaccination of commercial ewes and their lambs at weaning, the only significant difference in health, growth, and carcass traits between vaccinates and non-vaccinates was a slightly higher pneumonia treatment rate in vaccinated preweaned lambs (25.7%) compared to unvaccinated preweaned lambs (23.4%) ( P = 0.04)., Conclusion and Clinical Relevance: Although vaccination with the experimental subunit M. haemolytica vaccine induced high LtxA and TbpB antibodies, it did not reduce clinical disease in lambs following an experimental challenge study or in a controlled randomized field trial in a commercial sheep operation. Further research is required to identify additional protective antigens for a safe and effective ovine respiratory vaccine to reduce pneumonia losses in commercial sheep flocks., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Bighorn sheep (Ovis canadensis) across North America commonly experience population-limiting epizootics of respiratory disease. Although many cases of bighorn sheep pneumonia are polymicrobial, Mycoplasma ovipneumoniae is most frequently associated with all-age mortality events followed by years of low recruitment. Chronic carriage of M. ovipneumoniae by adult females serves as a source of exposure of naïve juveniles; relatively few ewes may be responsible for maintenance of infection within a herd. Test-and-remove strategies focused on removal of adult females with evidence of persistent or intermittent shedding (hereafter chronic carriers) may reduce prevalence and mitigate mortality. Postmortem confirmation of pneumonia in chronic carriers has been inadequately reported and the pathology has not been thoroughly characterized, limiting our understanding of important processes shaping the epidemiology of pneumonia in bighorn sheep. Here we document postmortem findings and characterize the lesions of seven ewes removed from a declining bighorn sheep population in Wyoming, USA, following at least two antemortem detections of M. ovipneumoniae within a 14-mo period. We confirmed that 6/7 (85.7%) had variable degrees of chronic pneumonia. Mycoplasma ovipneumoniae was detected in the lung of 4/7 (57.1%) animals postmortem. Four (57.1%) had paranasal sinus masses, all of which were classified as inflammatory, hyperplastic lesions. Pasteurella multocida was detected in all seven (100%) animals, while Trueperella pyogenes was detected in 5/7 (71.4%). Our findings indicate that not all chronic carriers have pneumonia, nor do all have detectable M. ovipneumoniae in the lung. Further, paranasal sinus masses are a common but inconsistent finding, and whether sinus lesions predispose to persistence or result from chronic carriage remains unclear. Our findings indicate that disease is variable in chronic M. ovipneumoniae carriers, underscoring the need for further efforts to characterize pathologic processes and underlying mechanisms in this system to inform management., (© Wildlife Disease Association 2024.)

Respiratory disease is one of the main diseases of sheep in many regions globally. Respiratory syncytial virus (RSV) causes severe disease in humans and in calves, but little is known about the role of RSV in sheep. We studied the prevalence of ovine RSV in sheep processed at 5 abattoirs in southern Australia. Bronchial swab samples were collected from 182 consignments of lambs up to 12 months of age and 71 consignments of adult sheep; these were tested for the presence of the virus using a qPCR based on the F gene sequence. Six of the 253 abattoir consignments (2.4%) tested positive for ovine RSV. Four of the positive consignments were lambs and 2 were adult sheep. To our knowledge, this is the first report of the ovine strain of RSV in sheep with pneumonia from Australia. Further research is needed to clarify the role of RSV in pneumonia in sheep., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Two adult mixed-breed ewes were presented with a 2-wk history of upper respiratory disease. Both animals were depressed, with bilateral serosanguineous nasal discharge and harsh bronchovesicular sounds accompanied by crackles and wheezes on auscultation. One animal was recumbent and was euthanized at presentation. The other animal with similar signs, as well as exophthalmos, was euthanized because of a mass in the nasal passages. On autopsy, severe pyogranulomatous and necrotizing ethmoidal rhinitis with focal pyogranulomatous pneumonia was diagnosed in both animals. An intralesional fungal organism was identified in the nares and lungs of both animals. The organism could not be isolated via fungal culture but was identified as Trichosporon sp. by a PCR assay. Trichosporon spp. are rarely associated with disease in veterinary medicine. This ubiquitous fungus might cause disease following trauma to the nasal passages or secondary to immunocompromise.

Habitat fragmentation is an important driver of biodiversity loss and can be remediated through management actions aimed at maintenance of natural connectivity in metapopulations. Connectivity may protect populations from infectious diseases by preserving immunogenetic diversity and disease resistance. However, connectivity could exacerbate the risk of infectious disease spread across vulnerable populations. We tracked the spread of a novel strain of Mycoplasma ovipneumoniae in a metapopulation of desert bighorn sheep Ovis canadensis nelsoni in the Mojave Desert to investigate how variation in connectivity among populations influenced disease outcomes. M. ovipneumoniae was detected throughout the metapopulation, indicating that the relative isolation of many of these populations did not protect them from pathogen invasion. However, we show that connectivity among bighorn sheep populations was correlated with higher immunogenetic diversity, a protective immune response and lower disease prevalence. Variation in protective immunity predicted infection risk in individual bighorn sheep and was associated with heterozygosity at genetic loci linked to adaptive and innate immune signalling. Together, these findings may indicate that population connectivity maintains immunogenetic diversity in bighorn sheep populations in this system and has direct effects on immune responses in individual bighorn sheep and their susceptibility to infection by a deadly pathogen. Our study suggests that the genetic benefits of population connectivity could outweigh the risk of infectious disease spread and supports conservation management that maintains natural connectivity in metapopulations., (© 2023 The Authors. Journal of Animal Ecology © 2023 British Ecological Society.)

Q fever is a zoonotic disease that is known to be widespread throughout the world by many researches since its discovery in 1935 and it is important in terms of animal and public health. Coxiella burnetii, which is the etiological agent of the disease, is an obligate intracellular pathogen. While the disease generally manifests itself with abortion in animals, disease manifests as atypical pneumonia or granulomatous hepatitis in the acute form and as endocarditis in the chronic form in humans. Its presence in Turkey has been shown with a large number of studies. The aim of this study was to show the genotypic relationship with MLVA analysis of C. burnetii samples found in cattle, sheep and goat samples in Erzurum and Samsun Veterinary Control Institutes and blood samples collected from humans with atypical pneumonia findings. In the study, MLVA analyses of 100 positive samples from 50 cows, 41 sheep and 9 goats from Northeast Anatolia and Black Sea regions and C. burnetii positive samples found in 6 individuals with atypical pneumonia were performed. As a result of the study, it was found that 106 C. burnetii samples had belong to 16 genotype groups. It was found that genotype XVI was the most prevalent among these groups and it was seen in both regions. In addition to this, genotype IX profile was the second largest group with 83.3% (5/6) of human samples. In this study, the genotypes common in the regions were determined and a data source was created for possible outbreaks., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Mycoplasma bovis , the most important primary pathogen in the family Mycoplasmataceae , causes pneumonia, arthritis, otitis media, and mastitis in cattle. Histopathologic pulmonary changes associated with M. bovis infection have been characterized as suppurative-to-caseonecrotic bronchopneumonia; infection in other organs has been reported in only a few studies that examined caseonecrotic endocarditis and suppurative meningitis. Granulomatous lesions associated with M. bovis infection have been reported only rarely. We studied the granulomatous inflammation associated with M. bovis infection in several organs of 21 Japanese Black cattle. M. bovis was detected by isolation and loop-mediated isothermal amplification methods; other bacteria were detected using culture on 5% blood sheep agar and a MALDI-TOF MS Biotyper. Tissues were examined by histopathology and by immunohistochemistry (IHC) using anti- M. bovis , anti-Iba1, anti-iNOS, and anti-CD204 antibodies. All 21 cases, which included 2 cases of meningitis-meningoencephalitis, 8 cases of endocarditis, and 11 cases of bronchopneumonia, had caseonecrotic granulomatous inflammation associated with M. bovis infection. The IHC for macrophages revealed a predominance of iNOS-labeled (M1) macrophages in the inner layer of the caseonecrotic granulomas associated with meningitis-meningoencephalitis, endocarditis, and bronchopneumonia in Japanese Black cattle naturally infected with M. bovis .

Bayesian networks are used to evaluate the effectiveness of mixed autogenous vaccines in fattening lambs to prevent the ovine respiratory syndrome. An experiment was performed with 460 fattening lambs, which were clustered into four groups according to the kind of vaccine received (Pasteurella spp., Mycoplasma spp., Mixed Mycoplasma-Pasteurella or placebo). After slaughtering, lungs were collected, and macroscopic and microscopic studies were performed. A microbiological study was carried out to evaluate the presence of Mycoplasma spp. and Pasteurellaceae by conventional culture and identification by nested polymerase chain reaction. To the best of the authors' knowledge, Bayesian networks have not been used to evaluate the effect of vaccines on the absence/presence of lung consolidation. Our results revealed that the use of mixed autogenous vaccines can decrease lung consolidation from 15.75% (12.42-19.08) to 9.24% (6.59-11.89). Therefore, the use of these autogenous vaccines in farms could be considered an effective control tool against ovine respiratory syndrome., (Copyright © 2019 Elsevier B.V. All rights reserved.)

There is a decline in sheep production and contribution to the economy. This study described the histological pattern, immunohistochemically demonstrate bacterial and viral agents of pneumonia in sheep slaughtered in metropolitan abattoirs in Nigeria and Ghana. A total of 805 (600 in Ghana and 205 in Nigeria) sheep lungs were examined for pneumonic lesions. Sections were fixed in 10% formalin for histological and immunohistochemical analysis. Pneumonia of 8.7% was in Ghana and 13.3% in Nigeria. The histological findings included bronchopneumonia (16/70), broncho-interstitial pneumonia (9/70), interstitial pneumonia (9/70) and proliferative pneumonia (7/70). Ten (14.3%) cases were positive for PPRV, PI3V, and RSV antigens while five (7.2%) were positive for multiple viral antigens; including two (PI3V and PPRV), two (RSV and PPRV), and one (PI3V and RSV). RSV was in interstitial pneumonia, PPRV and PI3V were in interstitial and broncho-interstitial pneumonia. PPRV and PI3V antigens 3 (4.4%) were in proliferative alveolitis. Mannheimia haemolytica (2) and Pasteurella multocida (2) infection were in combination with PPRV, RSV, and PI3V. Three sheep lungs (4.4%) were negative for viruses and bacteria. This study revealed ovine pneumonia is still a problem in West Africa, and multivalent vaccine incorporating some of these agents will be useful for the control.

Pasteurella multocida isa gram-negative bacterial pathogen that is causative agent of a wide range of diseases in many animal species and humans. Lipopolysaccharides (LPS) are an important virulence factor, minor changes to structure of which can exert dramatic effects on pathogenicity of P. multocida in its host. LPS can be used for the identification and classification of strains with somatic typing systems.The aim of this study was to identify the LPS genotypes of the ovine P. multocida isolates obtained from pneumonia cases in Iran. The LPS genotype of the isolates was determined using eight specific primers for LPS outer core biosynthesis loci. The LPS genes were amplified by polymerase chain reaction (PCR), then they were sequenced and compared to the sequences registered in the GenBank. Of the 32 ovine P. multocida isolates tested, 21 (65.62%) isolates belonged to genotype L6, 9 (28.12%) isolates contained genotype L3, 1 (3.12%) isolate had both L3 and L6 loci, and 1 (3.12%) isolate remained untypeable. The LPS-PCR was able to type 31 of 32 field ovine isolates from Iran. According to the phylogenetic analysis, L3 genotype isolates were grouped into two distinct lineages. LPS gene sequences among L6 genotypes of ovine P. multocida isolates from Iran and the related sequences in the GenBank were highly similar (>99.5%). LPS-PCR is an accurate genotyping method that was able to classify P. multocida strains into one of the eight distinct LPS genotypes., (Copyright © 2017, Archives of Razi Institute. Published by Kowsar.)

Leukotoxin producing (lkt+) members of Pasteurellaceae, particularly Mannheimia haemolytica and Bibersteinia trehalosi are important pathogens of pneumonia in bighorn sheep (BHS; Ovis canadensis), causing fatal disease. Predisposing or concurrent infection with Mycoplasma ovipneumoniae enhances the severity of the disease, resulting in increased morbidity and mortality. Several studies have investigated the effectiveness of vaccines against lkt+ members of Pasteurellaceae in preventing fatal pneumonia in BHS. In all of these studies, however, vaccinated animals were challenged experimentally, by direct inoculation of the pathogens, rather than by natural challenge. Moreover, none has investigated the efficacy of the vaccines under conditions of concurrent infection with M. ovipneumoniae. We immunized three bighorn rams and one pregnant ewe with an experimental multivalent vaccine along with a commercial vaccine. The immunized animals were then commingled with two bighorn ewes known to be carriers of lkt+ members of Pasteurellaceae, to simulate natural infection or disease transmission. All vaccinated animals remained healthy. We then inoculated the two carrier ewes with nasal washings from domestic sheep containing M. ovipneumoniae. Within a week, all animals developed mild to moderate signs of pneumonia. While the rams died within two-three months post-inoculation (p.i.), the vaccinated ewe and her lamb died five and eight months p.i., respectively. Taken together, these results suggest that vaccination of BHS against lkt+ members of Pasteurellaceae alone can protect them from natural challenge by these pathogens. However, it may not be adequate to protect them against pneumonia compounded by concurrent infection with M. ovipneumoniae., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Mycoplasma bovis arthritis and pneumonia in six-month-old calvesSudden deaths in housed suckler cows due to hypomagnesaemiaBovine respiratory syncytial virus infection in two-year-old heifersBovine abortion associated with Parachlamydia speciesFibrinous pericarditis due to Aeromonas hydrophila in weaner pigsThese are among matters discussed in the disease surveillance report for December 2016 from SAC Consulting: Veterinary Services (SAC C VS)., (British Veterinary Association.)

Fusobacterium necrophorum has been detected in pneumonic bighorn sheep (BHS; Ovis canadensis ) lungs, in addition to the aerobic respiratory pathogens Mannheimia haemolytica , Bibersteinia trehalosi , Pasteurella multocida , and Mycoplasma ovipneumoniae . Similar to M. haemolytica , F. necrophorum produces a leukotoxin. Leukotoxin-induced lysis and degranulation of polymorphonuclear leukocytes (PMNs) and macrophages are responsible for acute inflammation and lung tissue damage characteristic of M. haemolytica -caused pneumonia. As one approach in elucidating the role of F. necrophorum in BHS pneumonia, we determined the frequency of the presence of F. necrophorum in archived pneumonic BHS lung tissues, and susceptibility of BHS leukocytes to F. necrophorum leukotoxin. A species-specific PCR assay detected F. necrophorum in 37% of pneumonic BHS lung tissues (total tested n=70). Sequences of PCR amplicons were similar to the less virulent F. necrophorum subsp. funduliforme. Fusobacterium necrophorum leukotoxin exhibited cytotoxicity to BHS PMNs and peripheral blood mononuclear cells. As with the M. haemolytica leukotoxin, F. necrophorum leukotoxin was more toxic to BHS PMNs than domestic sheep PMNs. It is likely that F. necrophorum enters the lungs after M. haemolytica and other aerobic respiratory pathogens enter the lungs and initiate tissue damage, thereby creating a microenvironment that is conducive for anaerobic bacterial growth. In summary, Fusobacterium leukotoxin is highly toxic for BHS leukocytes; however, based on the PCR findings, it is unlikely to play a direct role in the development of BHS pneumonia.

Pneumonia in calves and finishers. Ovarian tumour in a calf . Abortion associated with bovine herpesvirus 1 in a suckler herd. Parasitic gastroenteritis causing illthrift and death in sheep. Outbreaks of acute fasciolosis in sheep. These are among matters discussed in the disease surveillance report for December 2015 from SAC Consulting: Veterinary Services (SAC C VS)., (British Veterinary Association.)

Parasitic pneumonia in cattleNutritional osteodystrophy in cattleWhite liver disease in lambsErysipelas in pigsLead poisoning and atherosclerosis in an eagle These are among matters discussed in the disease surveillance report for October 2015 from SAC Consulting: Veterinary Services (SAC C VS)., (British Veterinary Association.)

Background: Formerly, Arcanobacterium pyogenes was recently renamed Trueperella pyogenes. This opportunistic bacterium is related to miscellaneous pyogenic infections in animals. Most studies involving T. pyogenes are case reports, whereas few surveys have focused the major aspects of T. pyogenes infections involving a case series study design., Objective: The aim of this study was to retrospectively evaluate selected epidemiological and clinical aspects, as well as the in vitro antimicrobial susceptibility pattern of 144 cases of T. pyogenes infections among domestic animals from 2002 to 2012., Animals and Methods: T. pyogenes was isolated from different clinical specimens from cattle, goats, sheep, pigs, horses, dogs, and buffaloes. Correlations were assessed by the Chi-square or Fisher's exact tests., Results: Mastitis (45.1%), abscesses (18.0%), pneumonia (11.1%), and lymphadenitis (9.0%) were the most common clinical manifestations. In addition, the organism was also isolated from other miscellaneous clinical specimens from cases of septicemia, encephalitis, pyometra, prostatitis, orchitis, seminal vesiculitis, pericarditis, and omphalitis. No statistical association was observed between T. pyogenes infections and age, gender, or season across the study. The most effective drugs against the pathogen were florfenicol (99.1%), cefoperazone (96.0%), cephalexin (95.0%), and ceftiofur (94.8%). High resistance rates were observed against trimethoprim-sulfamethoxazole (49.3%), followed by norfloxacin (10.9%) and tetracycline (9.2%)., Conclusions: This study highlights the diversity of clinical manifestations and the opportunistic behavior of T. pyogenes infections in domestic animals, with predominance of mastitis, abscesses, pneumonia, and lymphadenitis. It also reinforces the importance of knowing the susceptibility profile before initiating therapy, to improve antimicrobial therapy approaches.

Group living facilitates pathogen transmission among social hosts, yet temporally stable host social organizations can actually limit transmission of some pathogens. When there are few between-subpopulation contacts for the duration of a disease event, transmission becomes localized to subpopulations. The number of per capita infectious contacts approaches the subpopulation size as pathogen infectiousness increases. Here, we illustrate that this is the case during epidemics of highly infectious pneumonia in bighorn lambs (Ovis canadensis). We classified individually marked bighorn ewes into disjoint seasonal subpopulations, and decomposed the variance in lamb survival to weaning into components associated with individual ewes, subpopulations, populations and years. During epidemics, lamb survival varied substantially more between ewe-subpopulations than across populations or years, suggesting localized pathogen transmission. This pattern of lamb survival was not observed during years when disease was absent. Additionally, group sizes in ewe-subpopulations were independent of population size, but the number of ewe-subpopulations increased with population size. Consequently, although one might reasonably assume that force of infection for this highly communicable disease scales with population size, in fact, host social behaviour modulates transmission such that disease is frequency-dependent within populations, and some groups remain protected during epidemic events., (© 2014 The Author(s) Published by the Royal Society. All rights reserved.)

Background: Bronchopneumonia is a population limiting disease of bighorn sheep (Ovis canadensis). The cause of this disease has been a subject of debate. Leukotoxin expressing Mannheimia haemolytica and Bibersteinia trehalosi produce acute pneumonia after experimental challenge but are infrequently isolated from animals in natural outbreaks. Mycoplasma ovipneumoniae, epidemiologically implicated in naturally occurring outbreaks, has received little experimental evaluation as a primary agent of bighorn sheep pneumonia., Methodology/principal Findings: In two experiments, bighorn sheep housed in multiple pens 7.6 to 12 m apart were exposed to M. ovipneumoniae by introduction of a single infected or challenged animal to a single pen. Respiratory disease was monitored by observation of clinical signs and confirmed by necropsy. Bacterial involvement in the pneumonic lungs was evaluated by conventional aerobic bacteriology and by culture-independent methods. In both experiments the challenge strain of M. ovipneumoniae was transmitted to all animals both within and between pens and all infected bighorn sheep developed bronchopneumonia. In six bighorn sheep in which the disease was allowed to run its course, three died with bronchopneumonia 34, 65, and 109 days after M. ovipneumoniae introduction. Diverse bacterial populations, predominantly including multiple obligate anaerobic species, were present in pneumonic lung tissues at necropsy., Conclusions/significance: Exposure to a single M. ovipneumoniae infected animal resulted in transmission of infection to all bighorn sheep both within the pen and in adjacent pens, and all infected sheep developed bronchopneumonia. The epidemiologic, pathologic and microbiologic findings in these experimental animals resembled those seen in naturally occurring pneumonia outbreaks in free ranging bighorn sheep.

Determination of regional blood flow by the injection of microspheres in sepsis models is crucial for the experimental evaluation of the influence of experimental treatment strategies on organ perfusion. However, multiple injections may critically increase the total quantity of microspheres, thereby restricting regional microcirculation and altering the results of blood flow measurements. This study was designed to compare the results of multiple versus single injections of microspheres in an established ovine sepsis model. Injury was induced by smoke inhalation and instillation of Pseudomonas aeruginosa into the lungs. Twenty sheep were studied for 4, 8, 12, 18, or 24 h, respectively. Microspheres were injected at the end of the study period and the animals were euthanized and organ tissues were harvested. Another four sheep were studied for 24 h and multiple microsphere injections were performed at the above indicated time points in the same animals. Tracheal blood flow significantly increased and blood flow to the pancreas and ileum significantly decreased versus baseline in both groups (P < 0.05 each). Blood flow to the ileum, renal cortex and skin did not significantly change versus baseline in both groups (P > 0.05). Blood flow was higher to the trachea in the multiple injection group at 18 h (P = 0.048) and to the ileum at 12 h (P = 0.049), and lower to the skin at 18 h (P = 0.015). In conclusion, the results indicate that multiple versus single microsphere injections induced no or negligible alterations during ovine sepsis. This finding may help reduce the quantity of animals needed in future experiments.

1. Bighorn sheep mortality related to pneumonia is a primary factor limiting population recovery across western North America, but management has been constrained by an incomplete understanding of the disease. We analysed patterns of pneumonia-caused mortality over 14 years in 16 interconnected bighorn sheep populations to gain insights into underlying disease processes. 2. We observed four age-structured classes of annual pneumonia mortality patterns: all-age, lamb-only, secondary all-age and adult-only. Although there was considerable variability within classes, overall they differed in persistence within and impact on populations. Years with pneumonia-induced mortality occurring simultaneously across age classes (i.e. all-age) appeared to be a consequence of pathogen invasion into a naïve population and resulted in immediate population declines. Subsequently, low recruitment due to frequent high mortality outbreaks in lambs, probably due to association with chronically infected ewes, posed a significant obstacle to population recovery. Secondary all-age events occurred in previously exposed populations when outbreaks in lambs were followed by lower rates of pneumonia-induced mortality in adults. Infrequent pneumonia events restricted to adults were usually of short duration with low mortality. 3. Acute pneumonia-induced mortality in adults was concentrated in fall and early winter around the breeding season when rams are more mobile and the sexes commingle. In contrast, mortality restricted to lambs peaked in summer when ewes and lambs were concentrated in nursery groups. 4. We detected weak synchrony in adult pneumonia between adjacent populations, but found no evidence for landscape-scale extrinsic variables as drivers of disease. 5. We demonstrate that there was a >60% probability of a disease event each year following pneumonia invasion into bighorn sheep populations. Healthy years also occurred periodically, and understanding the factors driving these apparent fade-out events may be the key to managing this disease. Our data and modelling indicate that pneumonia can have greater impacts on bighorn sheep populations than previously reported, and we present hypotheses about processes involved for testing in future investigations and management., (© 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.)

Individual host immune responses to infectious agents drive epidemic behavior and are therefore central to understanding and controlling infectious diseases. However, important features of individual immune responses, such as the strength and longevity of immunity, can be challenging to characterize, particularly if they cannot be replicated or controlled in captive environments. Our research on bighorn sheep pneumonia elucidates how individual bighorn sheep respond to infection with pneumonia pathogens by examining the relationship between exposure history and survival in situ. Pneumonia is a poorly understood disease that has impeded the recovery of bighorn sheep (Ovis canadensis) following their widespread extirpation in the 1900s. We analyzed the effects of pneumonia-exposure history on survival of 388 radio-collared adults and 753 ewe-lamb pairs. Results from Cox proportional hazards models suggested that surviving ewes develop protective immunity after exposure, but previous exposure in ewes does not protect their lambs during pneumonia outbreaks. Paradoxically, multiple exposures of ewes to pneumonia were associated with diminished survival of their offspring during pneumonia outbreaks. Although there was support for waning and boosting immunity in ewes, models with consistent immunizing exposure were similarly supported. Translocated animals that had not previously been exposed were more likely to die of pneumonia than residents. These results suggest that pneumonia in bighorn sheep can lead to aging populations of immune adults with limited recruitment. Recovery is unlikely to be enhanced by translocating naïve healthy animals into or near populations infected with pneumonia pathogens.

Thirty-one sheep naturally infected with small ruminant lentiviruses (SRLV) of known genotype (A or B), and clinically affected with neurological disease, pneumonia or arthritis were used to analyse mannose receptor (MR) expression (transcript levels) and proviral load in virus target tissues (lung, mammary gland, CNS and carpal joints). Control sheep were SRLV-seropositive asymptomatic (n = 3), seronegative (n = 3) or with chronic listeriosis, pseudotuberculosis or parasitic cysts (n = 1 in each case). MR expression and proviral load increased with the severity of lesions in most analyzed organs of the SRLV infected sheep and was detected in the affected tissue involved in the corresponding clinical disease (CNS, lung and carpal joint in neurological disease, pneumonia and arthritis animal groups, respectively). The increased MR expression appeared to be SRLV specific and may have a role in lentiviral pathogenesis.

Mannheimia haemolytica consistently causes fatal bronchopneumonia in bighorn sheep (BHS; Ovis canadensis) under natural and experimental conditions. Leukotoxin is the primary virulence factor of this organism. BHS are more susceptible to developing fatal pneumonia than the related species Ovis aries (domestic sheep [DS]). In BHS herds affected by pneumonia, lamb recruitment is severely impaired for years subsequent to an outbreak. We hypothesized that a lack of maternally derived antibodies (Abs) against M. haemolytica provides an immunologic basis for enhanced susceptibility of BH lambs to population-limiting pneumonia. Therefore, the objective of this study was to determine the titers of Abs directed against M. haemolytica in the sera of BH and domestic lambs at birth through 12 weeks of age. Results revealed that BH lambs had approximately 18-fold lower titers of Ab against surface antigens of M. haemolytica and approximately 20-fold lower titers of leukotoxin-neutralizing Abs than domestic lambs. The titers of leukotoxin-neutralizing Abs in the serum and colostrum samples of BH ewes were approximately 157- and 50-fold lower than those for domestic ewes, respectively. Comparatively, the higher titers of parainfluenza 3 virus-neutralizing Abs in the BH lambs ruled out the possibility that these BHS had an impaired ability to passively transfer Abs to their lambs. These results suggest that lower levels of leukotoxin-neutralizing Abs in the sera of BH ewes, and resultant low Ab titers in their lambs, may be a critical factor in the poor lamb recruitment in herds affected by pneumonia.

Systemic cladosporiosis is described in 25 merino sheep from a flock consisting 250 animals. The fungal pneumonia appeared after an intensive antibiotic treatment, because of a respiratory system disorder. The pen of the flock was humid and crowded, and animals had signs of respiratory distress, coughing, fever and anorexia. All of the ill animals died, and necropsy was performed on 10 sheep. The lesions were characterized by a multifocal pyogranulomatous pneumonia and an abomasitis. Severe hemorrhages were observed in the lungs. At the histopathological examination, severe vasculitis with thrombosis was observed in various organs, especially in the lungs and abomasums, suggestive for a hematogenous dissemination of the infection in these organs. Numerous PAS-positive fungal elements were seen in the pyogranulomatous foci. Dark green fungal colonies were seen in the blood agar and Sabouraud dextrose agar that were identified as Cladosporium cladosporioides. This report highlights that phaeohyphomycosis can cause a severe systemic and fatal disease in merino sheep under insufficient management conditions.

Subclinical pneumonia is common in production lambs, and causes reductions in growth rate. We selected farms from meat-inspection records of three New Zealand abattoirs from December 2000 to May 2001 to study risk factors for flocks having >or=3% of their lambs with >or=10% of the lung surface with lesions, compared to flocks with a zero lamb-level prevalence of such pneumonia. A questionnaire of management practices was mailed to participating managers of case and control farms and we received responses from 132/192 (69%) cases and 181/300 (60%) in control farms. Risk factors for case farms were shearing lambs on the day of weaning (OR 6.4), breeding ewe replacements on-farm (OR 4.0), and the percentage of lambs sold between March and May (OR 1.0 for <23% sold (reference category), OR 3.9 for 23-42% sold, OR 2.7 for 43-64% sold, OR 4.3 for >64% sold). Protective factors included: grazing lambs at a fixed stocking rate after weaning (OR 0.4), injecting lambs with vitamin B12 at the time of docking (OR 0.4), and at the time of weaning (OR 0.3). Path analysis was used to show important associations between risk and protective factors differentiated according to time (e.g. before and after birth, at weaning and during growth on pasture). Flocks breeding their own ewe replacements were more likely to shear lambs at weaning, were less likely to buy lambs post-weaning and more likely to have ill-thrift present in >5% of lambs post-weaning. The purchase of lambs post-weaning was indirectly associated with greater odds of pneumonia at slaughter.

Aim: To estimate the cost of pneumonia and pleurisy in lambs to the sheep industry in New Zealand, in order to provide a reference for future cost-benefit calculations for control programmes to reduce the incidence of pneumonia., Methods: An estimate of the economic cost of pneumonia and pleurisy in lambs was based on: cohort studies of the association between growth rate and the extent of pneumonic lesions at slaughter (n=14 flocks), the prevalence of moderate to severe (MS) pneumonia (> or =10% lung surface area affected) and pleurisy (n=1,719 flocks), the correlation between the prevalence of MS pneumonia and economic loss at the flock level, and data on annual slaughter statistics and carcass value in New Zealand. A stochastic spreadsheet model was developed and run with 1,000 iterations. Input variables represented by probability distributions were growth rate, average cost of loss according to the prevalence of pneumonia per month, carcass value, prevalence of pleurisy, and carcasses downgraded for pleurisy, and annual national slaughter statistics. The output was a posterior distribution of the annual cost of disease., Results: The cost of pneumonia only included the loss associated with reduced growth rate, while mortality due to pneumonia was assumed to be low and was ignored. The cost of pleurisy included the loss associated with downgraded or condemned carcasses. Thus, the simulated annual average cost of pneumonia was NZ$28.1 (95% CI=NZ$15.0-42.0) million, and that of pleurisy NZ$25.1 (95% CI=NZ$10.2-48.1) million. The combined cost of pneumonia and pleurisy averaged NZ$53.2 (95% CI=NZ$32.4-78.9) million. The parameters with the greatest impact on the combined cost of pneumonia and pleurisy were prevalence of pleurisy between March and May, and cost of reduced growth due to pneumonia for lambs slaughtered in June., Conclusions: The average cost of pneumonia and pleurisy to the sheep industry in New Zealand due to reduced lamb growth and decreased carcass value is likely to be between NZ$32.4 and $78.9 million. This is a conservative estimate, omitting mortalities, indicating that pneumonia and pleurisy have substantial economic impact on sheep farming in New Zealand. Considering that 23,833,000 lambs were slaughtered in 2003/2004 (average value $65.56/lamb), this cost would equate to NZ$1.36-3.31 per lamb., Clinical Relevance: Pneumonia and pleurisy are common diseases in lambs in New Zealand, leading to substantial economic loss to producers.

We recorded lesions of moderate-to-severe pneumonia (>or=10% lung surface area affected; "pneumonia") in 1,899,556 lambs submitted to three New Zealand abbatoirs between December 2000 and September 2001. The average prevalence of pneumonia ranged between 7 and 13%, by abbatoir. We ran a two-level mixed-effects binomial logistic-regression model with the prevalence of pneumonia as the outcome, and adjusting for abbatoir and month. The intracluster correlations for batch (slaughter lambs from the same farm sent at the same time) and farm were 31.3 and 12.4%, respectively. (We also noted threefold differences in odds across abbatoirs, and >30-fold differences among slaughter months.) Case flocks (those in the upper quintile of pneumonia prevalence) generally were not clustered in the spatial incidence-risk analysis (after adjusting for flock-level and batch level effects, and as compared to flocks in the lower two quintiles). We therefore concluded that the risk of moderate-to-severe pneumonia-lesion prevalence detectable at slaughter of lambs was determined at the flock and batch level, rather than at the spatial level.

A comprehensive study of a pneumonic epizootic was initiated when the first signs of disease were noted in a metapopulation of bighorn sheep inhabiting Hells Canyon, bordering Idaho, Oregon, and Washington. A total of 92 bighorn sheep were tested for etiologic agents during the following 6-mo study period. The study population included bighorn sheep believed to be the subpopulation in which disease was first noted, and these sheep were translocated to a holding facility in an effort to contain the disease (group A1, n = 72); bighorn sheep in other subpopulations (group A2) with evidence of clinical disease were captured, sampled, given antibiotics, and released (n = 8) and those that were found dead were necropsied (n = 12). Samples, including oropharyngeal and nasal swabs, and lung and liver tissue were collected from the bighorn sheep identified above. Tissue was collected at necropsy from 60 group A1 bighorn sheep that died following translocation, and samples were cultured for bacteria and viruses. Blood samples were tested for antibodies against known respiratory viruses, and histopathology was conducted on tissue samples. The major cause of death in both group A1 and group A2 bighorn sheep was a rapidly developing fibrinous bronchopneumonia. Multiple biovariants of Pasteurella were isolated from oropharyngeal and nasal samples from both groups, and Mycoplasma ovipneumonia was isolated from five group A1 oropharyngeal samples. Organisms isolated from lung tissue included Pasteurella multocida multocida a and Pasteurella trehalosi, both of which differentiated into multiple strains by restriction enzyme analysis, and parainfluenza-3 virus (PI-3). Paired serum samples revealed > fourfold increases in titers against PI-3 and bovine respiratory syncytial viruses. It was concluded that this epizootic resulted from a complex of factors including multiple potential respiratory pathogens, none of which were identified as a primary pathogen, and possible stress factors.

We describe health significance of protostrongylid parasites (Parelaphostrongylus odocoilei and Protostrongylus stilesi) and other respiratory pathogens in more than 50 naturally infected Dall's sheep (Ovis dalli dalli) from the Mackenzie Mountains, Northwest Territories (1998-2002) as well as in three Stone's sheep (O. d. stonei) experimentally infected with P. odocoilei (2000-2002). Histological lesions in the brain and distribution of P. odocoilei in the muscles of experimentally and naturally infected sheep were consistent with a previously hypothesized "central nervous system to muscle" pattern of migration for P. odocoilei. Dimensions of granulomas associated with eggs of P. odocoilei and density of protostrongylid eggs and larvae in the cranial lung correlated with intensity of larvae in feces, and all varied with season of collection. Prevalence of P. stilesi based on the presence of larvae in feces underestimated true prevalence (based on examination of lungs) in wild Dall's sheep collected in summer and fall. Similarly, counts of both types of protostrongylid larvae in feces were unreliable indicators of parasitic infection in wild Dall's sheep with concomitant bacterial pneumonia associated with Arcanobacterium pyogenes, Pasteurella sp., and Mannheimia sp. Diffuse, interstitial pneumonia due to P. odocoilei led to fatal pulmonary hemorrhage and edema after exertion in one experimentally infected Stone's sheep and one naturally infected Dall's sheep. Bacterial and verminous pneumonia associated with pathogens endemic in wild Dall's sheep in the Mackenzie Mountains caused sporadic mortalities. There was no evidence of respiratory viruses or bacterial strains associated with domestic ruminants, from which this population of wild sheep has been historically isolated.

The levels of, zinc, copper, Fe, Zn, Cu, Mn, Mg, K, Na, and Cl and the activity of carbonic anhydrase were determined in lambs with pneumonia. A significant decrease of p < 0.01 level in Zn concentration, in Cu level (p < 0.001) and significant increases in K and Na levels (p < 0.05) and of the Cu/Zn ratio (p < 0.001) were observed in the study group. The carbonic anhydrase activity was decreased in the study group, but the decrease was not statistically significant (p > 0.05). Also, nonsignificant decreases of Fe, Mg, and Cl and increase of the Mn concentration were also observed in the lambs with pneumonia (p > 0.05). Our results suggest that the significant element changes reported here and the Cu/Zn ratio, but not the activity of carbonic anhydrase, can be used as indicators of pneumococcal infection.

The diseases known as hepatitis cysticercosa and pneumonitis cysticercosa are caused by migrating Cysticercus tenuicollis, the intermediate stage of Taenia hydatigena, in the liver and lung tissue of intermediate hosts like sheep, goats, cattle, pigs and squirrels. In this study, parasitological and pathological examinations were performed on the liver and lung tissue samples of a one month old lamb that had died in a herd of Karadayi village, Bünyan, Kayseri. After the examination, hepatitis cysticercosa and parasitic verminous pneumonia (Pneumonitis cysticercosa) were diagnosed and the results were discussed.

Estimation of the intracluster correlation coefficient (ICC) for infectious animal diseases may be of interest for survey planning and for calculating variance inflation factors for estimators of prevalence. Typically, diagnostic tests with imperfect sensitivity and specificity are used in surveys. In such studies, where animals from multiple herds are tested, the ICC often is estimated using apparent (test-based) rather than true prevalence data. Through Monte Carlo simulation, we examined the effect of substituting diagnostic test outcomes for true infection status on an ANOVA estimator of ICC, which was designed for use with true infection status data. We considered effects of diagnostic test sensitivity and specificity on the estimated ICC when the true ICC value and infection status of the sampled individuals were known. The ANOVA estimator underestimated the true ICC when the diagnostic test was imperfect. We also demonstrated, under the beta-binomial model, that the ICC based on apparent infection status for individuals is < or = ICC based on true infection status. In addition, we propose a Bayesian model for estimating the ICC that incorporates imperfect sensitivity and specificity and illustrate the Bayesian model using a simulation study and one example; a seroprevalence survey of ovine progressive pneumonia in U.S. sheep flocks.

We propose a herd-level sample-size formula based on a common adjustment for prevalence estimates when diagnostic tests are imperfect. The formula depends on estimates of herd-level sensitivity and specificity. With Monte Carlo simulations, we explored the effects of different intracluster correlations on herd-level sensitivity and specificity. At low prevalence (e.g. 1% of animals infected), herd-level sensitivity increased with increasing intracluster correlation and many herds were classified as positive based only on false-positive test results. Herd-level sensitivity was less affected at higher prevalence (e.g. 20% of animals infected). A real-life example was developed for estimating ovine progressive pneumonia prevalence in sheep. The approach allows researchers to balance the number of herds and the total number of animals sampled by manipulating herd-level test characteristics (such as the number of animals sampled within a herd).

Mortality records from birth to weaning of 8,301 lambs from a composite population at the U.S. Meat Animal Research Center were analyzed using a competing risks model. The advantage of the competing risks model over traditional survival analyses is that different hazards of mortality can be assigned to different causes, such as disease, dystocia, and starvation. In this study, specific causes of mortality were grouped into dam-related (DAMR; e.g., dystocia and starvation), pneumonia (PNEU), disease (DIS; excluding pneumonia), and other (OTHER) categories. The hazard of mortality was analyzed using a competing risk approach, where each mortality category was assumed to be independent. Continuous- and discrete-time survival analyses were implemented using sire, animal, and maternal effects mixed models. The continuous-time survival analysis used the Weibull model to describe the hazard of mortality for each category of mortality. Under the discrete-time survival analysis, a complementary log-log link function was used to analyze animal-time data sets using weekly intervals for each category of mortality. Explanatory variables were sex, type of birth, contemporary group, and age of dam. The significant influences of type of birth and age of dam effects were consistent across category of mortality, and the sex effect was significant for all categories except the OTHER category. Estimates of variance components indicated strong maternal effects for all categories except for PNEU. Estimates of additive genetic heritabilities from the discrete maternal effects models were 0.08+/-0.04, 0.09+/-0.18, 0.16+/-0.12, 0.19+/-0.09, and 0.14+/-0.10 for OVERALL (all causes combined), DIS, DAMR, PNEU, and OTHER categories, respectively. Ignoring the cause of the defining event in mortality and longevity studies may hide important genetic differences. Therefore, the effectiveness of breeding programs relying on models that ignore multiple causes of an event in time-to-event data, such as mortality and longevity, could be affected.

The prevalence and serotypic diversity of Mannheimia [Pasteurella] haemolytica and Pasteurella trehalosi from nasal swabs, sera and abattoir specimens from sheep in the highlands of Wollo, North East Ethiopia was investigated. Prevalence rates of 83% and 75% of these microorganisms were found in the serum samples and nasal swabs, respectively, from apparently healthy sheep. In a local abattoir, 205 lungs were investigated, 34% of which showed pneumonia, from which samples were collected from 51 lungs and the same number of corresponding tonsils. Mannheimia and Pasteurella species were isolated from 59% of these pneumonic lungs and 69% of the respective tonsils. M. haemolytica serotypes accounted for 41 (59%) and P. trehalosi for 11 (32%) of the isolates from the abattoir specimens. The majority (67%) of isolates from nasal swabs were P. trehalosi, M. haemolytica being isolated f rom 4 (13%) of the swabs. M. glucosida was isolated only from the tonsils. The predominant serotypes of the isolates from both the nasal swabs and the abattoir specimens were M. haemolytica A1 (17%) and P. trehalosi T4 (16%) and T3 (13%). P. trehalosi T15 was less commonly encountered, while M. haemolytica A9 and A13 were not isolated. Studies on sera from 100 sheep indicated that antibodies against M. haemolytica serotype A1 (14%) were most common, followed by A5 and A8 (each 10%) and A9 and P. trehalosi T3 (each 9%) and T4 (8%). Antibodies against M. glucosida or serotype All occurred in 2% of the sera. Multiple serotypes were common in all types of samples. The importance of including in vaccines the most prevalent serotypes involved in the pneumonia of sheep in the area is discussed.

A survey among small ruminant veterinary practitioners and producers of the United States was conducted to determine the most important health problems of sheep and goats and the need for drugs to treat these diseases. Gastrointestinal nematodes and pneumonia were the most important health concerns. Ceftiofur, long acting tetracyclines, penicillins, tilmicosin and enrofloxacin were the antibiotics most needed. The approval of ivermectin and albendazole for goats, and fenbendazole for sheep were among the most common requests for anthelmintics. Veterinarians also stressed the need for drugs to manipulate the estrous cycle, anti-inflammatory drugs, analgesics and anesthetics. Among the viral diseases, lentivirus infections (ovine progressive pneumonia and caprine arthritis encephalitis) and soremouth were the greatest concerns among veterinarians and producers. Both groups indicated that the availability of a generic antiviral drug would be important. The lack of a rabies vaccine was of great concern particularly among goat producers. Extra-label use of drugs in food animals may result in drug residues in tissues that may be hazardous for consumers. Therefore; in order for producers to provide high quality, safe products while remaining competitive in a global market economy, research to determine safety levels and tissue depletion times of new drugs is an urgent need for the sheep and goat industry.

In 144 clinical healthy and 97 sick sheep pneumotachographic investigations were performed. In 119 sheep the diagnoses "healthy" based on adspection, auscultation and palpatory percussion. In 25 additional healthy and in the sick animals the diagnoses based on clinical, endoscopical, serological, parasitological, and in 82 animals also pathomorphological findings. According to these diagnoses the animals were divided into the following groups: G = healthy, K = catarrhal purulent bronchopneumonia, E = suppurative pneumonia, W = verminous pneumonia, M = Maedi, MKE = Maedi + catarrhal purulent or suppurative pneumonia, MAKE = Maedi + Adenomatosis + catarrhal purulent or suppurative pneumonia, AKE = Adenomatosis + catarrhal purulent or suppurative pneumonia, and FAKE = animals of the AKE group at an earlier date of investigation. In all sheep respiration rate, tidal and minute volumes, forced tidal volume, peak flow and resistance were measured with the portable pneumotachograph Flowscreen. Tidal and minute volumes and flow rates depended at rest as well as after forced ventilation essentially from the respiratory rate and from the body weight of the animals. The average individual coefficients of variation of repeated measurements of healthy animals were between 21% and 36%. Only in tidal volume after forced ventilation (10%) and in the resistance (18%) the individual coefficients of variations were lower. In 57% of the animals with Lung Adenomatosis resistance-values over 0.4 kPa*s/l were measured, but in 94% of the sheep without adenomatosis resistance-values remained under this limit.

Verminous pneumonias appear to be common in sheep in Morocco, therefore, a systematic study was undertaken to classify the pulmonary changes induced by various parasites in Morocco. A total of 613 pairs of lungs with parasitic pneumonias were diagnosed in 1152 young and adult sheep either slaughtered at two abattoirs in Morocco (487 out of 1152 sheep) or received at necropsy services (126 out of 1152 sheep) over a 15-month period. Based on gross and microscopic findings, four types of pulmonary changes were classified. Included were those associated with: 1. The larvae of Taenia echinococcus (Echinococcus granulosus (canine tapeworm); 520 out of 613 lungs (84.8%)); 2. Muellerius capillaris (450 out of 613 lungs (79.9%)); 3. Protostrongylus rufescens (375 out of 613 lungs (61.1%)); and 4. Dictyocaulus filaria (285 out of 613 lungs (46.4%)). Mixed infestations, involving the presence of two, three, or four species of parasites in the same lung, were encountered in 325 out of 613 (53%) lungs studied. Red-to-brownish consolidated areas, confined to the cranial parts of the lung, were observed frequently in some lungs affected with M. capillaris and P. rufescens. In most of the lungs, co-existent emphysematous, atelectatic, and abscessed areas were seen.

Bacteria resembling two Bordetella species were isolated from both normal and pneumonic ovine lungs using a selective charcoal agar. Twenty-eight of the 33 isolates showed similarities to stock NCTC B. parapertussis strains in their SDS-PAGE gel protein profiles, in their biochemical reactions and in causing browning on tyrosine agar. Five isolates behaved similarly to stock B. bronchiseptica strains, in being actively motile, in giving identical positive reactions in three out of four biochemical tests and in causing no colour change in tyrosine agar. Multilocus enzyme electrophoresis separated the isolates into two electrophoretic types distinguishable from those of stock B. parapertussis and stock B. bronchiseptica strains.

Pasteurella haemolytica isolates from clinical veterinary samples were serotyped over a three year period to determine the distribution of strains in Northern Ireland, to compare the results with the recorded distribution in the remainder of Great Britain and to extend information on the geographical prevalence of the serotypes. Four hundred and nine typable and 91 untypable strains were isolated from 490 animal cases. From 127 typable cattle isolates, the commonest serotype was A1, most frequently associated with calf pneumonia. Serotypes A2, T4, T10 and T15 were the commonest sheep isolates, A2 being most frequently associated with lamb pneumonia and the T-biovars more prevalent in adult pneumonia and lamb septicaemia. The isolates from approximately half the cases were evaluated in terms of the results obtained from gross and histopathological post mortem examination. Approximately two-thirds of these isolates were associated with significant pathology, including a small number of serotypes which are not included in the sheep vaccines currently used in Great Britain.

Pneumonia has been identified as a major cause of poor lamb survival in indigenous herds of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) in central Idaho. Pasteurella haemolytica was isolated from five adult Rocky Mountain bighorn ewes captured from a free-ranging herd in central Idaho. The lambs from two of these ewes delivered by cesarean section were free of P. haemolytica until 40 days of age and after repeated contact with their dams. The lambs subsequently developed signs of pneumonia, and P. haemolytica was isolated from nasal, pharyngeal, and transtracheal wash samples from each lamb. All P. haemolytica biotype T isolates from the ewes and lambs, as well as those from a 9-month-old lamb of the same herd from which samples for culture were obtained 2 years earlier, were subjected to HaeIII restriction enzyme analysis (REA) and ribotyping. Two ribotypes and seven REA patterns were visually distinguishable by these procedures. Similarity coefficients (SAB) of 0.09 to 0.95 were calculated for the seven REA patterns. The REA patterns of the isolates from the lambs were identical (SAB = 1.0). The isolates from the lambs also had SAB values of 1.0, which was indicative of identity with one of the seven isolates cultured from the ewes at the time of capture and with the organism isolated from the 9-month-old lamb. These procedures have the discriminatory capabilities necessary to monitor the transmission of specific strains of bacteria within and between animal populations.

Two areas of drug needs in the sheep industry are reviewed. The first is the need for prolificacy drugs such as those used outside the country. These drugs would encourage out-of-season lambing, increased lambs/per ewe during the traditional lambing season and synchronize estrus for easier management of lambing and increased use of artificial insemination for faster genetic improvement. The other area is drugs to treat or prevent major causes of disease, specifically abortion, neonatal diarrhea, pneumonia and internal parasitism. Efficacious drugs for these diseases are either not now cleared for use in sheep at all; a safe, easy to administer product is not available; or not cleared for sheep at a dosage level which is effective. These are drugs which will have a positive impact on the industry by increasing production, reducing expenses, and helping the U. S. to be able to compete with other sheep producing countries in the U. S. markets.

Factors affecting morbidity and mortality of the Ethiopian highland sheep were studied both on-farm and on-station at Debre Berhan between 1989 and 1990. Primary causes of infectious origin resulted in high proportional morbidity (88.4% on-farm) and mortality (72.9% on-farm and 71.8% on-station) rates. Nutritional and managemental factors were also responsible for mortalities in lambs. The most frequent secondary causes of morbidity and/or mortality were ectoparasites and nasal myiasis. Health management interventions on-station were not high enough to produce performance improvements above the on-farm levels. However, the occurrence of gastrointestinal parasites significantly (P < 0.05) differed between the two management systems. The frequency of some of the major causes of morbidity and mortality such as pneumonia, fasciolasis and enteritis were significantly (P < 0.01) affected by season and age of an animal. In order to alleviate the major health constraints identified in this study, a proper health management intervention involving vaccination, strategic anthelmintic treatment and feeding management are suggested.

Four shed-lambing operations in western Colorado were monitored during the 1984 spring lambing season to determine the causes and rates of perinatal lamb mortality. The number of lambing ewes per flock ranged from 513 to 1,712, and lambing percentages ranged from 131 to 180%. Overall perinatal lamb mortality ranged from 8.2 to 12.2%. Most lamb deaths occurred during parturition or within 24 hours after parturition. More than 85% of all lamb deaths were in lambs born to ewes having 2 or more lambs. The leading causes of lamb death were starvation, dystocia, stillbirth (unknown cause), and infectious diseases. A wheel model was used to categorize factors causing lamb deaths into 4 groups: physical, social, host, and biological, and to present data on perinatal lamb mortality in a simple visual model. In all flocks, social and biological factors resulted in most of the lamb deaths. On the basis of our findings, we suggest that interventions designed to improve ewe-lamb bonding and to reduce infectious agents and the incidence of prolonged parturition may reduce lamb mortality.

A study was conducted to investigate causes of lamb morbidity and mortality on farms and on-station at Debre Berhan during 1989 and 1990. It showed pneumonia (bacterial and/or verminous), starvation-mismothering exposure (SME) complex, gastrointestinal parasites, enteritis, abomasal impaction and physical injuries to be important health constraints on productivity. Neonatal mortalities were 51.5% and 46.3% on farms and on-station respectively and occurred owing to management problems such as SME, abomasal impaction and physical injuries. On the farms the lamb birth weight was 2.56 +/- 0.25 kg and was significantly (p < 0.05) affected by the dam's age, lambing weight, litter size, sex of lamb and year of lambing, but not by the season of lambing. Birth weight significantly (p < 0.05) influenced lamb mortality. Lambs with a low birth weight tended to die from SME. Morbidities and mortalities due to infectious causes increased in older lambs, suggesting that infections were acquired with age when resistance was lowered owing to inadequate nutrition and poor management. Heavy loss of lambs could be overcome by such health management interventions as foster mothering, warming lambs during the cold season and vaccination with polyvalent vaccines against pasteurellosis, clostridial infection and Dictyocaulus filaria.