Veterinary Medicine Commons^™

Determination Of Multidrug Resistance (Mdr1) Gene And Its Mutations In Dogs By Using Polymerase Chain Reaction, Sariya Asawakarn, Valaiporn Ruangchaiprakarn, Naparee Srisowanna, Leelawat Wongwan, Anusorn Kanuengthong, Gunnaporn Suriyaphol

The Thai Journal of Veterinary Medicine

The objective of this study is to establish a polymerase chain reaction (PCR) laboratory for detection of multidrug resistance1 (MDR1) mutation in Thailand. Blood samples were collected from 67 dogs, namely 16 Collies, 9 Shetland Sheepdogs, 5 Border Collies, 6 Shih tzus, 13 German Shepherds and 18 mixed breeds. Genomic DNA was extracted and PCR was performed to amplify 341 and 577 bp fragments to detect homozygous wild-type (+/+) and homozygous mutant (-/-), respectively. For the heterozygous mutant (+/-), both PCR fragments would be presented. An analysis of DNA sequences encompassing the 4-base pair deletion in the coding region of …

Seroprevalence And Risk Factors Associated With Leptospirosis (L. Interrogans) In Bovine Cattle In Northeastern Mexico, Verónica Carvajal-De La Fuente, Cecilia Zapata-Campos, Jorge Loredo-Osti, Rigoberto López-Zavala, José Osiel Jasso-Obregón, Edgar Martínez-Bautista

The Thai Journal of Veterinary Medicine

The seroprevalence of Leptospira interrogans serovars in cattle was determined by analyzing 385 serum samples from 8 Rural Development Districts (RDD), in Tamaulipas, Mexico. A microscopic agglutination test (MAT) including 9 serovars of L. interrogans as antigens was used. Serum samples were considered positive when 50% or more of agglutination in a dilution of ≥ l:100 was observed. A total of 70.4% animals were reported positive for one or more serovars. The most frequent antibodies reported were those against serovars tarassovi (53.25%) hardjo (23.64%) and canicola (15.32%), whilst serovar bataviae (0.52%) was found at lower frequency. Mante district showed the …

Effect Of Anthocyanin’S Extract From Flour Of Roselle Calyx (Hibiscus Sabdariffa) On Growth And Pigmentation Of Goldfish (Carassius Auratus), Verónica Pérez-Escalante, Gabriel Aguirre-Guzmán, Pablo Emilio Vanegas-Espinoza, Alma Angélica Del Villar-Martínez

The Thai Journal of Veterinary Medicine

Goldfish (Carassius auratus) is an ornamental fish. The aim of this work was to evaluate the effect of diet supplemented with anthocyanin from roselle (Hibiscus sabdariffa) on survival, growth, and chromatophores identification in skin of goldfish (C. auratus). Three experimental diets were prepared from commercial feed for tilapia added with 40, 80 or 160 mg of pigment from roselle/kg. Survival and biometric parameters such a growth, weight gain, feed intake, and feed conversion ratio were evaluated. Histological analyses from some tissues were made. Survival values and biometric parameters were higher in goldfish fed added with roselle in comparison to control …

Development Of A Fluorescent Microsphere Immunoassay For Detection Of Antibodies Against Porcine Reproductive And Respiratory Syndrome Virus Using Oral Fluid Samples As An Alternative To Serum-Based Assays, Robert J. Langenhorst, Steven Lawson, Apisit Kittawornrat, Jeffery J. Zimmerman, Zhi Sun, Yanhua Li, Jane Christopher-Hennings, Eric A. Nelson, Ying Fang

Veterinary and Biomedical Sciences Faculty Publications

For effective disease surveillance, rapid and sensitive assays are needed to detect antibodies developed in response to porcine reproductive and respiratory syndrome virus (PRRSV) infection. In this study, we developed a multiplexed fluorescent microsphere immunoassay (FMIA) for detection of PRRSV-specific antibodies in oral fluid and serum samples. Recombinant nucleocapsid protein (N) and nonstructural protein 7 (nsp7) from both PRRSV genotypes (type I and type II) were used as antigens and covalently coupled to Luminex fluorescent microspheres. Based on an evaluation of 488 oral fluid samples with known serostatus, the oral fluid-based FMIAs achieved >92% sensitivity and 91% specificity. For serum …

Method For Screening For A Tobiano Coat Color Genotype, Ernest Bailey, Samantha A. Brooks

Veterinary Science Faculty Patents

A method for screening for a Tobiano genotype includes obtaining a nucleic acid from an equine animal, and analyzing the nucleic acid for the presence of an inversion in a chromosome ECA3q which is indicative of the genotype for Tobiano. The method includes detecting at least one of a telomeric breakpoint of an inverted ECA3q chromosome and/or a centromeric breakpoint of an inverted ECA3q chromosome. In one embodiment, the nucleic acid may be analyzed by the steps of hybridizing the group of probes or primers having the sequences set forth herein in SEQ ID NO:8, SEQ ID NO: 9, and …

Zwitterionic Chitosan Derivative, A New Biocompatible Pharmaceutical Excipient, Prevents Endotoxin-Mediated Cytokine Release, Gaurav Bajaj, William G. Van Alstine, Yoon Yeo

Department of Comparative Pathobiology Faculty Publications

Chitosan is a cationic polymer of natural origin and has been widely explored as a pharmaceutical excipient for a broad range of biomedical applications. While generally considered safe and biocompatible, chitosan has the ability to induce inflammatory reactions, which varies with the physical and chemical properties. We hypothesized that the previously reported zwitterionic chitosan (ZWC) derivative had relatively low pro-inflammatory potential because of the aqueous solubility and reduced amine content. To test this, we compared various chitosans with different aqueous solubilities or primary amine contents with respect to the intraperitoneal (IP) biocompatibility and the propensity to induce proinflammatory cytokine production …

A High Density Snp Array For The Domestic Horse And Extant Perissodactyla: Utility For Association Mapping, Genetic Diversity, And Phylogeny Studies, Molly E. Mccue, Danika L. Bannasch, Jessica L. Petersen, Jessica Gurr, Ernie Bailey, Matthew M. Binns, Ottmar Distl, Gérard Guérin, Telhisa Hasegawa, Emmeline W. Hill, Tosso Leeb, Gabriella Lindgren, M Cecilia T. Penedo, Knut H. Røed, Oliver A. Ryder, June E. Swinburne, Teruaki Tozaki, Stephanie J. Valberg, Mark Vaudin, Kerstin Lindblad-Toh, Claire M. Wade, James R. Mickelson

Veterinary Science Faculty Publications

An equine SNP genotyping array was developed and evaluated on a panel of samples representing 14 domestic horse breeds and 18 evolutionarily related species. More than 54,000 polymorphic SNPs provided an average inter-SNP spacing of ∼43 kb. The mean minor allele frequency across domestic horse breeds was 0.23, and the number of polymorphic SNPs within breeds ranged from 43,287 to 52,085. Genome-wide linkage disequilibrium (LD) in most breeds declined rapidly over the first 50-100 kb and reached background levels within 1-2 Mb. The extent of LD and the level of inbreeding were highest in the Thoroughbred and lowest in the …

Investigation Of The Effects Of Co2 Insufflation On Blood Gas Values During Laparoscopic Procedures In Pigs, Özlem Güzel, Di̇lek Olğun Erdi̇kmen, Di̇dar Aydin, Zi̇hni̇ Mutlu, Esma Yildar

Turkish Journal of Veterinary & Animal Sciences

Due to the fact that they produce less post-operative pain and shorter hospitalisation times, laparoscopic surgery procedures are more widely used than many traditional open surgical methods. However, the carbon dioxide gas used to visualise the surgical site during the procedure causes complications such as an increase in the blood CO_2 level and acidosis. In the present study, 12 male pigs were used. Sedation was achieved via intramuscular injection of xylazine at a dose of 2 mg/kg and anaesthesia induction was done via slow intravenous injection of ketamine HCl at a dose of 2 mg/kg. Following endotracheal intubation, general anaesthesia …

An Hsi Report: Industrial Farm Animal Production And Livestock Associated Mrsa (Methicillin Resistant Staphylococcus Aureus), Humane Society International

HSI REPORTS

Staphylococcus aureus is a leading cause of bacterial infection and is increasingly found to be resistant to antibiotic therapy. A newly described type of Methicillin Resistant Staphylococcus aureus carried by farm animals, Livestock Associated MRSA (LA-MRSA), is now causing infections in humans with and without direct livestock contact. A reduction in the non-therapeutic use of antibiotics in feed would likely reduce the capacity of industrial animal agriculture to continue to create, disseminate, and perpetuate a large reservoir of LA-MRSA on a global scale, but more fundamental changes in the way animals are raised for food may be necessary forestall a …

Puppy Buyer Complaints: A Five-Year Summary, 2007‐2011, The Humane Society Of The United States

PUPPY MILL REPORTS

The Humane Society of the United States receives complaints about sick puppies on a daily basis. Over a five-year period (2007-2011), our puppy mills campaign received 2,479 puppy buyer complaints. The complaint came to The HSUS via our website complaint form (www.humanesociety.org/puppycomplaint), by email, and through our puppy mills tip line. Buyers complained about sick puppies sold by a variety of sources, including pet stores, breeders (both in person and online), or middleman dealers (sometimes known as brokers). Unsatisfied buyers contact The HSUS for many reasons; some are seeking information about how to pursue their consumer complaint, others …

Veterinary Problems In Puppy Mill Dogs, The Humane Society Of The United States

PUPPY MILL REPORTS

Dogs in puppy mills often suffer from an array of painful and potentially life-shortening veterinary problems due to overcrowded, unsanitary conditions and the lack of proper oversight or veterinary care. Conditions common to puppy mills, such as the use of stacked, wire cages to house more animals than a given space should reasonably hold, as well as constant exposure to the feces and urine of other dogs, make it difficult for dogs to avoid exposure to common parasites and infectious diseases. In addition, a lack of regular, preventive veterinary care, clean food and water, basic cleaning and grooming, and careful …

Clinical Anesthesia And Analgesia In Fish, Lynne U. Sneddon

Veterinary Science and Medicine Collection

Fish have become a popular experimental model and companion animal, and are also farmed and caught for food. Thus, surgical and invasive procedures in this animal group are common, and this review will focus on the anesthesia and analgesia of fish. A variety of anesthetic agents are commonly applied to fish via immersion. Correct dosing can result in effective anesthesia for acute procedures as well as loss of consciousness for surgical interventions. Dose and anesthetic agent vary between species of fish and are further confounded by a variety of physiological parameters (e.g., body weight, physiological stress) as well as environmental …

Characterisation Of Chemosensory Trigeminal Receptors In The Rainbow Trout, Oncorhynchus Mykiss: Responses To Chemical Irritants And Carbon Dioxide, Jessica J. Mettam, Catherine R. Mccrohan, Lynne U. Sneddon

Veterinary Science and Medicine Collection

Trigeminally innervated, mechanically sensitive chemoreceptors (M) were previously identified in rainbow trout, Oncorhynchus mykiss, but it is not known whether these receptors are responsive only to noxious, chemical irritants or have a general chemosensory function. This study aimed to characterise the stimulus–response properties of these receptors in comparison with polymodal nociceptors (P). Both P and M gave similar response profiles to acetic acid concentrations. The electrophysiological properties were similar between the two different afferent types. To determine whether the receptors have a nociceptive function, a range of chemical stimulants was applied to these receptors, including non-noxious stimuli such as ammonium …

Prevalence Of Antibodies To Canine Parvovirus And Distemper Virus In Wolves In The Canadian Rocky Mountains, Brynn Nelson, Mark Hebblewhite, Vanessa Ezenwa, Todd Shury, Evelyn H. Merrill, Paul C. Paquet, Fiona Schmiegelow, Dale Selp, Geoff Skinner, Nathan Webb

Epidemiology Collection

Wild carnivores are often exposed to diseases via contact with peridomestic host species that travel through the wildland-urban interfaces. To determine the antibody prevalences and relationships to human activity for two common canid pathogens, we sampled 99 wolves (Canis lupus) from 2000 to 2008 for antibodies to canine parvovirus (CPV) and canine distemper virus (CDV) in Banff and Jasper National Parks and surrounding areas of the Canadian Rockies. This population was the source for wolves reintroduced into the Northern Rockies of the US. Of 99 wolves sampled, 94 had detectable antibody to CPV (95%), 24 were antibody-positive for CDV (24%), …

Mammary Cell Activity And Turnover In Dairy Cows Treated With The Prolactin-Release Inhibitor Quinagolide And Milked Once Daily, M. Boutinaud, V. Lollivier, L. Finot, R. M. Bruckmaier, P. Lacasse

Physiology Collection

To assess the regulation of mammary cell activity, survival, and proliferation by prolactin (PRL), 5 Holstein cows in early lactation received daily i.m. injections of 1 mg of quinagolide, a suppressor of PRL release, for 9 wk, whereas 4 control cows received the vehicle (water) only. During the last week of treatment, one udder half was milked once a day (1×) and the other twice a day (2×). Mammary biopsies were harvested 1 wk before and 4 and 8 wk after the start of quinagolide treatment. The quinagolide injections reduced milk yield and resulted in lower levels of κ-casein and …

Diagnosis Of Porcine Teschovirus Encephalomyelitis In The Republic Of Haiti, Ming Y. Deng, Max Millien, Rodney Jacques-Simon, J. Keith Flanagan, Alexa J. Bracht, Consuelo Corrillo, Roger W. Barrette, Andrew Fabian, Fawzi Mohamed, Karen Moran, Jessica Rowland, Sabrina L. Swenson, Melinda Jenkins-Moore, Leo Koster, Bruce V. Thomsen, Gregory Mayr, Dave Pyburn, Paula Morales, John Shaw, Thomas Burrage, William White, Michael T. Mcintosh, Samia Metwally

Zoonotics and Wildlife Disease: Publications

In February and March 2009, approximately 1,500 backyard pigs of variable age became sick, and approximately 700 of them died or were euthanized in the Lower Artibonite Valley and the Lower Plateau of the Republic of Haiti. The main clinical sign was posterior ataxia followed by paresis and/or paralysis on the second or third day of illness. No gross lesions were observed at postmortem examinations. The morbidity and mortality were approximately 60% and 40%, respectively. Diagnostic samples (whole blood, brain, tonsil, lymph nodes, spleen, and lung) were negative for Classical swine fever virus and African swine fever virus. Porcine …

A Microscopic And Stereological Study Of The Renal Artery Transitional Zone Of The Adult Male Dog, Fatemah Ramezani Nowrozani

Turkish Journal of Veterinary & Animal Sciences

A transitional zone in the dog renal artery was documented and its parameters were recorded: length and volumes of the luminal wall, tunica intima, tunica media, and tunica adventitia-as well as these parameters in the non-transitional zone of artery. Twelve normal adult male dogs were studied. The specimens were processed in the routine manner for light and electron microscopy. After the determination of transitional zone length by light microscope, for the stereological study each renal artery was divided into transitional and non-transitional zones, and paraffin blocks were prepared. It was established that the transitional zone contains parallel and continuous elastic …

The Role Of Gylcoprotein K (Gk) In The Ocular And Neuropathogenesis Of Herpes Simplex Virus-Type 1 (Hsv-1), Andrew Timothy David

LSU Doctoral Dissertations

Herpes simplex virus type 1 (HSV-1) is a DNA virus that is a ubiquitous pathogen of humans. The hallmark of the HSV-lifecycle is infection of a mucosal surface with spread to sensory neurons where the virus establishes a latent infection with periodic recurrences for the life of the host. The most common course of symptomatic disease with HSV-1 is the typical mucocutaneous lesion that is self-limiting. HSV-1 can also cause acute encephalitis and ocular pathology on reactivation. Both of these manifestations of the disease have severe consequences. Although ocular infection is less frequent, the extensive prevalence of HSV makes it …

Essential Role Of Monocyte Chemoattractant Protein-1 In Gram-Negative Bacterial Pneumonia, Gayathriy Balamayooran

LSU Doctoral Dissertations

Acute gram-negative bacterial infections are a leading cause of mortality among the nosocomial infections. Increasing numbers of immunosuppressed individuals and growing numbers of antibiotic resistant strains make antibiotic treatment difficult. Neutrophils are the first cells recruited to the site of infection and are critical players in the host defense against gram-negative bacterial pneumonia. Therefore, identification of targets that boost neutrophil-associated host defense in the lung is essential in designing better therapies to control pulmonary infections. Production of chemokines is an important step for neutrophil recruitment. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that is important for monocyte and T-lymphocyte influx. …

The Toxicity Of Acetaminophen, Caffeine And Carbendazim In Earthworms (Eisenia Fetida), Matthew M. Bulman

Masters Theses

There has been a need for the assessment of ground water contamination risk on terrestrial organisms. One terrestrial organism, Eisenia fetida, was chosen as a test species and exposed to three common pharmaceutical and/or pesticide related contaminants: acetaminophen (CAS#103-90-2), caffeine (CAS#58-08-2) and carbendazim (CAS#10605-21-7), respectively. Levels of contamination varied from grams per liter to micrograms per liter (ppb) using distilled water as the solvent. Eisenia fetida was examined through a 28 day range/index toxicity test. A Benchmark Dose (BMD) dichotomous probit analysis, using a 95% confidence interval, was calculated for all three contaminants. All three contaminants were found to have …

Isospora Species (I. Canaria, Isospora Sp.) In Canaries (Serinus Canarius, Linnaeus), Cem Ecmel Şaki̇, Edi̇p Özer

Turkish Journal of Veterinary & Animal Sciences

Of 64 canaries with diarrhea in Elazığ Province between May 2002 and May 2006, 18 (28.1%) had Isospora oocysts in their feces. It was determined that the oocysts, examined morphologically before and after sporulating, were Isospora canaria and Isospora sp. Among the infected animals, 8 (44.4%) were concurrently infected with both species. Total numbers of I. canaria oocysts were greater than those of Isospora sp. A total of 2 canaries showing severe clinical signs were necropsied. Liver, spleen, and lung preparations and peripheral blood smears of the necropsied animals were examined for Atoxoplasma, and no development forms were seen. For …

Prolonged Dystocia, Uterine Necrosis, And Ovariohysterectomy In A Chios Ewe, Christos N. Brozos, Lazaros Lazarides, Isidoros Karagiannis, Evangelos Kiossis, Georgios Tsousis, Vasilios Psychas, Nektarios Giadinis

Turkish Journal of Veterinary & Animal Sciences

A 4-year-old Chios ewe was submitted to the Clinic of Farm Animals (School of Veterinary Medicine, Aristotle University of Thessaloniki). The animal had delivered 2 healthy lambs, 2 days earlier, and was inappetent, depressed, and reluctant to move, while it had tachycardia and tachypnea. The cervix was opened at a dilation of 1 finger in diameter and fetid fetal membranes expelled from the vagina. Serum biochemistry revealed renal and liver disease, while ultrasonography revealed uterine dilatation. Laparotomy revealed a partly autolysed embryo in the uterus and gangrenous metritis. Clostridium perfringens and Escherichia coli were isolated in bacterial cultures from the …

Ingestion Of Endophyte-Infected Tall Fescue Seed Induces Peripheral Vasoconstriction But Does Not Affect Cyclicity In Non-Pregnant Mares, And A Population Of Biogenic Amine Receptors Relative To Vasoconstriction Is Identified, Daniel Andrew Hestad

Theses and Dissertations--Veterinary Science

Three experiments were conducted to explore the effect of fescue toxicosis on vasoconstriction and various parameters of the estrous cycle. In the experiment of Chapter 3, a 2x2 crossover experimental design with repeated measures was implemented to test whether the ingestion of endophyte-infected tall fescue seed would alter blood hormone concentrations of prolactin, progesterone, and estradiol, interovulatory intervals, and corpus luteum blood flow. Also, Doppler ultrasonography was used to assess whether palmar artery and palmar vein lumen diameter, area, circumference, and resistivity index could be altered by the ingestion of endophyte-infected tall fescue seed. Ingestion of endophyte-infected tall fescue seed …

The Transmission Dynamics Of Equine Herpesvirus Type 1 (Ehv-1) Infection In Outbreaks Characterized Predominately By Neurologic Or Respiratory Illness, Barry Jay Meade

Theses and Dissertations--Veterinary Science

Formalized epidemiological field investigations were conducted to compare and contrast the transmission dynamics of EHV-1 neurological disease among horses stabled at Churchill Downs Racetrack, Louisville, Kentucky and of EHV-1 respiratory illness among horses stabled in the student barn at Murray State University. Differences were assessed by means of statistical and mathematical modeling techniques applied to survey and biological data collected over the course of the respective disease events.

Regression methods applied to survey data enabled the construction of a statistical model to predict a date of onset of illness for horses within each equine cohort. Comparisons of the epidemic curves …

Breeding Induced Endometritis In The Mare: The Local Innate Immune Response, Elizabeth Moran Woodward

Theses and Dissertations--Veterinary Science

Uterine inflammation after breeding is considered necessary for the clearance of excess semen and debris from the uterus. A subpopulation of mares fails to clear the inflammation in a timely fashion, and develops a persistent breeding induced endometritis (PBIE). Experiments were preformed to evaluate correlations of PBIE to endometrial quality and age. Mares of advanced age and poor endometrial quality had a higher incidence of PBIE. In addition, mares fluctuated in susceptibility to PBIE from one season to the next. The uterine inflammatory gene expression in susceptible and resistant mares within the first 24 hours after breeding was investigated. The …

Development Of Molecular Diagnostic Assays For Equine Respiratory Viruses And Analysis Of The Role Of Equine Arteritis Virus Envelope Proteins In The Early Events Of Virus Entry, Zhengchun Lu

Theses and Dissertations--Veterinary Science

There is an urgent need for detection of viral respiratory pathogens to identify the causal agent(s) involved and to prevent the spread of related diseases. The first part of this dissertation focuses on development, optimization and validation of Real-time reverse transcription polymerase chain reaction (rRT-PCR) assays for the detection of several common equine viral pathogens: equine arteritis virus (EAV), equine influenza virus and equine rhinitis viruses A and B. Emphasis of the second part of this dissertation is on studying the role of EAV envelope proteins in virus attachment and entry. Using an infectious cDNA clone of EAV and reverse …

Role Of Herpes Simplex Type I Glycoproteins In Entry And Cell-Cell Fusion, Sona Chowdhury

LSU Doctoral Dissertations

Herpes simplex virus type I (HSV-1) is a neurotropic virus that infects primarily mucocutaneous epithelial cells and nervous tissue. Membrane fusion is an important aspect of the HSV-1 lifecycle, that occurs during viral entry (virus-cell fusion), viral spread (cell-to-cell fusion), as well as, during virion morphogenesis (assembly and egress). These membrane fusion steps involve complex interactions between multiple viral glycoproteins and cellular receptors. HSV-1 glycoprotein B (gB) is necessary but not sufficient for membrane fusion events. Despite the fact, that the majority of known hypermorphic mutations which cause extensive virus-induced cell fusion occur within glycoprotein K (gK); yet the role …

Evaluation Of Plasma Sprayed Hydroxyapatite Coated Ao Cortical Screws In Equine Third Metacarpal Bone, Myra Elizabeth Durham

LSU Master's Theses

ABSTRACT Objectives - To compare the osteointegration of plasma sprayed hydroxyapatite (HA) coated and uncoated 5.5 mm cortical screws in equine third metacarpal (MC3) bones in combination with a 4.5mm broad dynamic compression plate (DCP). Study design - In vivo study. Animals – 6 Adult Thoroughbred horses. Methods – For each horse, four HA coated screws were placed unicortically through a 4.5mm broad DCP in the dorsal cortex of a randomly chosen MC3 bone, with 4 uncoated screws placed in an identical manner in the contralateral MC3 bone. All screws were tightened to a torque of 5.4 N-m. Extraction torques …

Isolation And Characterization Of Adult Progenitor Cells From Healthy And Laminitic Hoof Tissue, Vanessa Pinto

LSU Master's Theses

Laminitis is an often fatal condition in horses with few available and only moderately effective treatment options. Separation of laminar dermis and epidermis lead to rotation or ventral deviation of the third phalanx inside the hoof capsule. Despite being a modified skin, equine laminar tissue does not completely return to normal after laminitis. The hypothesis tested was that adult progenitor cells in the equine laminar tissue are irreversibly damaged by laminitis. A method to harvest and culture cells in vitro from the equine lamina was established; and progenitor cells from unaffected and laminitic hooves were characterized and compared. Laminar tissue …

Morphological Characterization Of The Immune Organs In Ostrich Chicks, Hui Song, Ke-Mei Peng, Sheng-He Li, Yan Wang, Lan Wei, Li Tang

Turkish Journal of Veterinary & Animal Sciences

This study describes the anatomical, light microscopic, and ultrastructural characterization of the immune organs in ostrich chicks. In this study 6 healthy 8-week-old ostrich chicks were processed for light and transmission electron microscopy. Hematoxylin and eosin as well as improved Weigert staining were used for light microscopy. The small thymus, which clustered caudally along both sides of the neck, contained Hassall's corpuscles in the medulla. The cloacal bursa, which formed the hanging and lateral walls of the cloaca, enveloped the cloaca but did not form a truly independent bursa. Inside the bursa convex papillae were densely distributed on the surface …