Alpaca (Vicugna pacos) Skin Analyzed Under Architecture and Structure / Piel de Alpaca (Vicugna pacos) Analizada Bajo Arquitectura y Estructura

SUMMARY: This study evaluated the morphology of alpacas skin. Biopsies were collected and samples were fixed in 10 % neutral buffered formalin for histological procedures. The sections were stained with hematoxylin and eosin, picrosirius red and Masson's trichrome. Types I, III and IV collagen were analyzed by immunohistochemistry. The derma presented sebaceous and sweat glands, as well as follicular groups with medullated fibers. Type I and type IV collagen were observed at epidermis and dermis as well as in glandular structures and hair follicles. The collagen III, was observed only in dermis.

Este estudio evaluó la morfología de la piel de alpacas. Se recogieron biopsias y las muestras se fijaron en formalina tamponada neutra al 10 % para procedimientos histológicos. Las secciones se tiñeron con hematoxilina y eosina, rojo picrosirius y tricrómico de Masson. El colágeno tipo I, III y IV se analizó mediante inmunohistoquímica. La dermis presentó glándulas sebáceas y sudoríparas, así como grupos foliculares con fibras medulares. Se observó colágeno tipo I y tipo IV en la epidermis y la dermis, así como en estructuras glandulares y folículos pilosos. El colágeno III, se observó únicamente en la dermis.

Estudio morfométrico y ecuaciones de predicción del peso corporal en llamas (Lama glama) Ch'aku y Q'ara / Morphometric study and body weight prediction equations in llamas (Lama glama) Ch'aku and Q'ara

RESUMEN: En el estudio se utilizó una población de 180 llamas de ambos sexos (machos y hembras) clasificados por edades (dientes de leche; dos dientes y cuatro dientes). Se registraron datos del peso corporal y las siguientes medidas morfométricas: En la cabeza: Longitud de la cabeza (LC); ancho de cabeza (ACa) y longitud de oreja (LO). En el cuello: Longitud del cuello (LCU); Perímetro de cuello anterior (PCuA) y perímetro de cuello posterior (PCuP). En el tronco y extremidades: Altura a la cruz (AC); altura de la grupa (AGRU), diámetro dorso esternal (DDE), perímetro torácico (PT), longitud del cuerpo (LOCU), longitud de la cruz a la grupa (LCG), longitud de grupa (LGRU), perímetro de caña anterior (PCA); perímetro de caña posterior (PCP). Los datos fueron procesados utilizando el software estadístico R. Concluyendo que los rasgos de conformación en llamas (Lama glama) Ch'aku y Q'ara están influenciados por la edad, sexo y raza. Los modelos de regresión simple y múltiple para la predicción del peso corporal fueron significativos.

SUMMARY: The study used a population of 180 llamas of both sexes (males and females) classified by age (milk teeth; two teeth and four teeth). Body weight data and the following morphometric measurements were recorded: Head: Head length (CL); head width (ACa) and ear length (LO). On the neck: Neck length (LCU); anterior neck circumference (PCuA) and posterior neck circumference (PCuP). On the trunk and limbs: Height at withers (AC); height at rump (AGRU), sternal dorsal diameter (DDE), thoracic perimeter (PT), body length (LOCU), length from withers to rump (LCG), rump length (LGRU), anterior canine perimeter (PCA); posterior canine perimeter (PCP). The data were processed using R statistical software. It was concluded that conformation traits in Ch'aku and Q'ara llamas (Lama glama) are influenced by age, sex and breed. Simple and multiple regression models for body weight prediction were significant.

Development of the Liver in Alpaca (Vicugna pacos): A Microscopic and Macroscopic Description.

South American camelids have several biological, morphological and behavioural adaptations that allow them to live in geographical areas dominated by high altitudes. The liver has hematopoietic functions during the prenatal life, which could be modified in response to the unfavorable habitat. However, there are no previous data on the prenatal development of the liver in these species. In the present work, a study on the macroscopic and microscopic morphology of the liver of the alpaca during ontogeny was performed. Forty-one animals ranging in age from 20 days of embryonic development to adults were studied. Macroscopic and microscopic observations were performed on samples subjected to different techniques. Less than 7-g specimens were studied with stereoscopic magnifying glass. The general characteristics of the prenatal liver are similar to those of other mammals, and the structures related to hematopoietic function follow an ontogenic pattern similar to that of previously studied precocial species. However, there are differences in morphology when compared to descriptions for the Old World camelids, including the absence of relation between the caudate lobe and the right kidney and the lack of interlobular connective tissue.

High follicle density does not decrease sweat gland density in Huacaya alpacas.

When exposed to high ambient temperatures, mammals lose heat evaporatively by either sweating from glands in the skin or by respiratory panting. Like other camelids, alpacas are thought to evaporate more water by sweating than panting, despite a thick fleece, unlike sheep which mostly pant in response to heat stress. Alpacas were brought to Australia to develop an alternative fibre industry to sheep wool. In Australia, alpacas can be exposed to ambient temperatures higher than in their native South America. As a young industry there is a great deal of variation in the quality and quantity of the fleece produced in the national flock. There is selection pressure towards animals with finer and denser fleeces. Because the fibre from secondary follicles is finer than that from primary follicles, selecting for finer fibres might alter the ratio of primary and secondary follicles. In turn the selection might alter sweat gland density because the sweat glands are associated with the primary follicle. Skin biopsy and fibre samples were obtained from the mid-section of 33 Huacaya alpacas and the skin sections were processed into horizontal sections at the sebaceous gland level. Total, primary, and secondary follicles and the number of sweat gland ducts were quantified. Fibre samples from each alpaca were further analysed for mean fibre diameter. The finer-fibred animals had a higher total follicle density (P<0.001) and more sweat glands (P<0.001) than the thicker-fibred animals. The fibre diameter and total follicle density were negatively correlated (R(2)=0.56, P<0.001). Given that the finer-fibred animals had higher follicle density and more sweat glands than animals with thicker fibres, we conclude that alpacas with high follicle density should not be limited for potential sweating ability.

Llama oviductal sperm reservoirs: involvement of bulbourethral glands.

The aim of this study was to elucidate the role of llama seminal plasma in the formation of oviductal sperm reservoirs. Female llamas with follicles in the mature phase were mated with a bulbourethral glands-removed male. Females mated with nonbulbourethral glands-removed males were used as control. Oviducts were obtained by surgery 24 h after mating. The uterotubal junction and isthmus were examined by scanning electron microscopy, and mucopolysaccharides were identified by Alcian blue staining. To know the proteins probably involved in sperm reservoir formation, SDS-PAGE of seminal plasma (8% and 18% resolving gel) was made. Spermatozoa only adhered to the oviductal mucosa surface of uterotubal junction of females mated with nonbulbourethral glands-removed males confirming that seminal plasma and, in particular, bulbourethral secretions are related with the oviductal sperm reservoir formation. Histological sections showed sperm in the lumen, immersed in substance, positive for acid mucopolysaccharides. Alcian blue staining of seminal plasma proteins SDS-PAGE showed a band of high molecular weight containing mucopolysaccharides, only present in nonbulbourethral glands-removed males. Bulbourethral glands would secrete at least eight different proteins that most likely participate in the process of sperm storage in the oviduct.

Inervación de las regiones escapular, braquial y antebraquial de la llama (Lama glama) / Innervation of the scapular, brachial and antebrachial of the llama (Lama glama)

La llama (Lama glama) es un mamífero cuya producción ha crecido exponencialmente en las últimas décadas, sobre todo en la región noroeste y patagónica de Argentina, Chile, Bolivia y Perú. Asociada a este crecimiento, la clínica médica veterinaria ha tenido que enfrentarse con el desafío de nuevos diagnósticos neuroanatómicos, así como también con maniobras semiológicas y quirúrgicas específicas para esta especie. El objetivo del presente trabajo es realizar una detallada descripción de la inervación de las regiones de la espalda, el brazo y el antebrazo, aportando conocimientos que sean de utilidad para que el veterinario clínico pueda interpretar alteraciones funcionales o para la realización de tratamientos quirúrgicos, terapéuticos y/o diagnósticos. Se incluye además la descripción de las relaciones musculares y vasculares de los nervios.

The llama (Lama Glama) is a mammal whose production has grown exponentially in the last decades, especially in the Northwest and Patagonian region of Argentina, Chile, Bolivia and Peru. Associated with this growth, veterinary medical clinic has had to deal with the challenge of new neuroanatomical diagnostic, as well as surgical and semiological maneuvers specific to this species. This work aims to make a detailed description of the innervation of the regions back, arm, and forearm, providing knowledge that is useful to the clinical veterinarian to interpret functional alterations or for the performance of surgical, therapeutic, treatment and/or diagnosis. It also includes the description of the muscular and vascular relationships of nerves.

Estudio morfológico de testículo de híbridos de alpaca (Lama pacos L.1758) y llama (Lama glama L. 1758) / Morphological study of testis of hybrid alpaca (Lama pacos L. 1758) and llama (Lama glama L. 1758)

En el presente estudio se ha realizado una descripción histológica básica de la estructura de testículos de machos híbridos resultantes del cruce de llama (Lama glama L.1758) y alpaca (Lama pacos L.1758), a los que se llama guarizos o huarizos. Como la fisiología reproductiva de estos híbridos es desconocida, nos pareció importante y necesario realizar estudios histológicos básicos para predecir si tienen capacidad reproductiva, ya que como híbridos se les considera estériles. Para ello se han analizado los testículos izquierdos de 10 híbridos de edades comprendidas entre 2 y 5 años, fijándolos en solución Bouin e incluyéndolos en parafina. Se han estudiado al microscopio óptico cortes histológicos de 5 micras de grosor, conteniendo en todos los casos túbulos seminíferos, para estudiar el epitelio germinal. En algunos casos se incluía el epidídimo, para determinar si su histología es normal y compatible con una posible funcionalidad. Estas secciones fueron teñidas con hematoxilina­eosina (HE) y/o con HE-PAS. El estudio de estas secciones permitió observar en los túbulos seminíferos todos los tipos celulares esperados: células de Sertoli, células de Leydig, espermatogonias y espermatocitos, todos ellos de aspecto normal. En el caso de las células de Sertoli, algunas de ellas presentaban un alto grado de vacuolización, lo que también se considera normal por la gran presencia de gotas lipídicas. En otras ocasiones en ciertas células de Sertoli se detectaron burbujas o huecos esféricos vacíos, que en la literatura se considera que corresponde a los espacios que ocupaban células germinales ya desaparecidas. La constitución histológica del epidídimo resultó normal. Por lo tanto, el estudio histológico de los testículos de estos híbridos permite concluir que la estructura de los túbulos seminíferos es aparentemente normal y que parecen formar espermatocitos también normales, lo que podría sugerir la posibilidad de que estos híbridos tengan cierto grado de fertilidad...

In the present study was carried out a description of the basic histological structure of testes in male hybrids of crossings of llama (Lama glama L.1758) and alpaca (Lama pacos L.1758), which is called guarizos or huarizos. As the reproductive physiology of these hybrids is unknown, it seemed important and basic histological studies are needed to predict if they have reproductive capacity because they are considered as sterile hybrids.To do this we have analyzed the left testes of 10 hybrid aged 2 and 5 years, fixing them in Bouin solution and including them in paraffin. Were studied by light microscopy histological sections of 5 microns in thickness, containing in all cases seminiferous tubules to study the germinal epithelium. In some cases, including the epididymis, to determine if the histology is normal and compatible with a possible functionality. These sections were stained with hematoxylin-eosin (HE) and / or HE-PAS. The study of these sections allowed the seminiferous tubules observed in all cell types expected: Sertoli cells, Leydig cells, spermatogonia and spermatocytes, all of them look normal. In the case of Sertoli cells, some of which exhibited a high degree of vacuolization, which is also considered normal by the presence of large lipid droplets. At other times in some Sertoli cells were detected hollow spherical bubbles or voids, in the literature is considered to correspond to the spaces occupied by germ cells and missing. The constitution of the epididymis was histologically normal.Therefore, histologic examination of the testes of these hybrids can be concluded that the structure of seminiferous tubules with apparently normal and spermatocytes also appear to be normal, which could suggest the possibility that these hybrids have some degree of fertility...

Arthroscopic approach and intraarticular anatomy of the stifle in South American camelids.

OBJECTIVE: To describe a cranial arthroscopic approach to the stifle of South American camelids and to report our clinical experience with camelid stifle arthroscopy. STUDY DESIGN: Experimental study and retrospective case series. ANIMALS: (1) Cadaveric alpaca hindlimbs (n = 18; 9 alpacas); (2) 1 alpaca and 1 llama METHODS: Polymethylmethacrylate joint casts (n = 2) were made to define stifle joint dimensions. Cadaveric stifle joints (n = 16) were evaluated arthroscopically to determine arthroscopic portal locations, describe the intraarticular anatomy, and report potential complications. An alpaca and a llama with stifle joint disease had diagnostic arthroscopy. RESULTS: Successful entry into the stifle joint was achieved in 16 cadaver limbs. Observed structures were: the suprapatellar pouch, articular surface of the patella, femoral trochlear ridges and groove, cranial aspect of the femoral condyles (n = 16); distal aspect of the cranial and proximal aspect of the caudal cruciate ligaments (14); and cranial aspects of the medial and lateral menisci (11), and cranial meniscotibial and intermeniscal ligaments (8). Stifle arthroscopy allowed for joint evaluation and removal of osteochondral fragments in 1 alpaca and 1 llama with naturally occurring stifle disease. Complications of cadaver or live procedures included minor cartilage scoring (3 stifles) and subcutaneous periarticular fluid accumulation (8 stifles). CONCLUSIONS: Arthroscopy provides a safe approach for diagnosis and treatment of stifle lesions in South American camelids.

Testicular cytology of alpaca: comparison between impressed and smeared slides.

Testicular fine needle aspiration (TFNA) has proven to be a simple and minimally invasive procedure, which allows assessments of cytological parameters of seminiferous epithelium/tubules more accurately in a short time. Though this technique does not cause negative effects on sperm quality or any damage to testicular tissue, its use is very limited in male animal infertility diagnostics. Report on the use of this technique in South American Camelids (SAC) is very limited. Therefore, the aim of this study was to evaluate the efficacy of TFNA for identification of different testicular cells and cell indices, and their correlation with that of impression cytology. A total of 98 slides were prepared from testes of six adult alpaca males, collected immediately after slaughter. Aspiration samples were performed by inserting a fine butterfly needle (21 G) connected to a 50 ml syringe into a testicle and multiple plane aspirations were carried out to obtain the materials destined to the smear. Three different imprints on slides were taken from each testicle. All slides were air-dried, stained with modified May--Grünwald--Giemsa (MGG) stain and then examined under light microscope with 1000× magnifications. Spermatogenic cells such as, spermatogonia (Sg), primary spermatocytes, secondary spermatocytes, early spermatids (ab), late spermatids (cd) and spermatozoa, and Sertoli cells were counted. The spermatozoa percentage was expressed as spermatic index (SI) and the number of Sertoli cells, counted apart, was expressed as sertoli cell index (SEI). There was not any significant difference between the spermatogenic cell parameters obtained from the two types of slides, but SEI were significantly different in two types of smears. The results of the study provide support for the use of TFNA as a useful minimally invasive modality to identify different spermatogenetic cell classes in alpaca. Moreover, the possibility to standardize this method might provide a greater impulse to the clinical diagnostics of SAC male infertility.

The microanatomy of healthy skin from alpacas (Vicugna pacos).

The microanatomy of healthy skin from 12 different body sites was investigated in 14 alpacas (Vicugna pacos). The microanatomy of alpaca skin is typical of domestic animal skin in general, and closely resembles that from llamas.

Identificación de las células de paneth en el intestino delgado de crías de alpacas en los primeros 21 días de edad / Identification of paneth's cells in the small intestine of baby alpacas in the first 21 days of age

Las células de Paneth cumplen un rol muy importante en los mecanismos de defensa y protección del tracto gastrointestinal en diferentes especies animales a través de sus secreciones como lisozima, fosfolipasa y A2 secretoria y defensinas. El presente estudio tuvo por objetivo identificar las células de Paneth en el intestino delgado de crías de alpacas; para lo cual se utilizaron 18 animales entre 1 y 21 días de edad. Se tomaron muestras de duodeno, yeyuno e íleon de cada animal, las cuales fueron fijadas en formol al 10 por ciento y procesadas como muestras histológicas. Se prepararon láminas coloreadas con hematoxilina-eosina (H-E) y tricrómico de Masson. Mediante inmunohistoquímica se identificó la presencia de gránulos de lisozima para lo cual se utilizó un anticuerpo policlonal antilisozima. Mediante la coloración con H-E y tricrómico de Masson no se pudo identificar en forma precisa células típicas de Paneth, mientras que mediante inmunohistoquímica se observó células con presencia de gránulos de lisozima en la base de las criptas de Lieberkühn de duodeno, yeyuno e íleon desde 1 día de edad, siendo mayor el número en yeyuno e íleon en alpacas entre los 15 y 21 días de edad. Estas células presentaron áreas comprendidas entre 129.19 y 147.67 µm2, ejes mayores entre 17.96 y 19.92 µm y ejes menores entre 8.68 y 9.79 µm. Por lo tanto, se concluye que las células encontradas desde el primer día de edad en las criptas de Lieberkühn de duodeno, yeyuno e íleon de crías de alpacas son las células de Paneth, siendo mayor su número en yeyuno e ileon entre los 15 y 21 días de edad.

Paneth cells have an important function in the defense and protection mechanisms of gastrointestinal tract in many animal species through its secretions as lysozime, sycretory phospholipase A2 and defensins. The aim of this study was to identify the Paneth cells in the small intestine of baby alpacas; for this, 18 animals between 1 and 21 days of age were used for this purpose. Duodenum, jejunum and ileum samples were removed from each animal. By routinary microscopic light examination and immunohistochemistry, these samples were fixed in 10 per cent phormol and processed for paraffin sections and stained with haematoxylin-eosin (H-E) and Masson trichromic. For immunohistochemistry technique we used a polyclonal antibody anti-lizozime. Typicall Paneth cells were not identified with H-E and Masson trichromic stains, where as by immunohistochemistry technique Iysozime granules conteining cells were identified in the base of the crypts of Lieberkuhn of duodenum, jejunum and ileum since 1 day of age, being the number bigger in jejunum and ileum of alpacas between 15 and 21 days of age. These cells showed areas between 129.19 and 147.67 µm2, major axes between 17.96 and 19.92 µm and minor axes between 8.68 and 9.79 µm. Based in this results, it was concluded that the cells found since the first day of age in the crypts of Lieberkuhn of duodenum, jejunum and ileum of baby alpacas are Paneth cells, being the number bigger in jejunum and ileum between 15 and 21 days of age.

Esophageal anatomy of the llama (Lama glama) / Anatomía del esófago de la llama (Lama glama)

This study describes gross, microscopic and muscle fiber anatomy of the esophagus of the llama, Lama glama. The esophagus was studied grossly in twenty-five adult llamas and a subset of ten with normal esophageal physiology was used for the microanatomic studies. Esophageal length was 122 +/- 7 cm with two-thirds of the length in the neck and the remainder in the thorax, consistent with the long neck of the llama. Esophageal diameter increased steadily from 2.5 +/- 0.3 cm in the cranial cervical region to 3.9 +/- 0.8 cm in the caudal thoracic region. The mucosal epithelium was keratinized stratified squamous and there were abundant submucosal glands throughout the esophagus. The entire muscularis of the esophagus was striated muscle in two general layers but also with a somewhat random orientation of fibers. The tunica muscularis steadily increased in thickness from 3.43 +/- 0.30 mm in the cranial cervical region to 4.39 +/- 0.39 mm in the middle thoracic region. In the llama Type 2 muscle fibers predominated in the esophageal musculature, with the percentage of Type 1 fibers increasing from 1 percent cranially to 33 percent in the caudal thoracic region of the esophagus. This study of the normal llama esophagus enhances our knowledge of this species and provides the basis for future study of pathological conditions of the esophagus.

Este estudio describe la anatomía morfológica, microscópica, y tipo de fibra muscular del esófago de la llama, Lama glama. Estudiamos la anatomía morfológica del esófago, con fisiología normal, en 25 llamas adultas y, adicionalmente, en 10 de ellas la anatomía microscópica. La longitud del esófago fue 122 +/- 7 cm con dos tercios en el cuello y un tercio en el tórax. El diámetro del esófago aumentó de 2,5 +/- 0,3 cm en la región craneal del cuello y a 3,9 +/- 0,8 cm en la región caudal del tórax. El epitelio de la mucosa eera escamoso estratificado queratinizado y la submucosa contenía abundantes glándulas a lo largo de todo el esófago. La muscular entera del esófago se compuso de músculo esquelético en más o menos dos capas, pero con algunas fibras orientadas al azar. La muscular aumentó de 3,43 +/- 0,30 mm en la región craneal del cuello a 4,39 +/- 0,39 mm en la región media del tórax. Fibras musculares Tipo 2 predominaron en la muscular. El porcentaje de fibras Tipo 1 aumentó de 1 por ciento al inicio del esófago a 33 por ciento en la región caudal torácica. Este estudio del esófago normal de la llama ofrece más información sobre la anatomía de la llama y proporciona una base para futuros estudios de patologías esofágicas.

Músculo romboides supraescapular de la Llama (Lama glamá) / Rhomboideus suprascapularis muscle of the llama (Lama glama)

El músculo romboides (m. rhomboideus) forma parte de la sinsarcosis que une la cintura del miembro torácico con el esqueleto axil en los mamíferos domésticos. En estas especies, está integrado por los músculos romboides cervical (m. rhomboideus cervicis) y romboides torácico (m. rhomboideus thoracis), siendo imposible establecer el límite entre ellos, a diferencia de lo que sucede en el Hombre. Los carnívoros en general, el cerdo y el conejo presentan, además de las partes mencionadas, el músculo romboides de la cabeza (m. rhomboideus capitis). En la llama, la porción cefálica está ausente y la cervical pobremente desarrollada. Los autores proponen sumar a las porciones cervical y torácica del músculo romboides de este camélido sudamericano, al músculo romboides supraescapular (m. rhomboideus suprsacapularis), descrito por Lesbre (1903), en el camello y el dromedario. En este trabajo se establecen las inserciones, dimensiones e inervación del músculo romboides supraescapular de la llama, elementos que permiten definirlo como otra porción del complejo muscular romboideo en dicha especie. Además, se postula su acción como elevador de la escápula, dirigiéndola craneal y dorsalmente.

The rhomboideus muscle of the domestic mammals is part of the muscular set that joins the scapular waist to the axial skeleton. In these animals, the forenamed muscle has a cervical portion (m. rhomboideus cervicicis), and a thoracic portion (m. rhomboideus thoracis). Unlike in the man, these parts cannot be separated. In addition, carnivores, pigs and rabbits also have a cephalic portion (m. rhomboideus capitis). In the llamas, the cephalic portion is absent, and the cervical part is poorly developed. The authors propose to add a suprascapular portion (m. rhomboideus suparsacapularis), first described by Lesbre, 1903 in camels, to the Rhomboideus muscular complex of the llama. In this study, the authors describe the length, insertions, and inervation of the Rhomboideus Suprascapular muscle of the llama in order to define it as another portion of the Rhomboideus muscular complex. Moreover, the forenamed muscle is proposed as a scapular elevator.

Gastrointestinal surgery in alpacas and llamas.

The clinical signs associated with acute abdominal pain in South American camelids tend to be subtle and less frequent (similar to ruminants) as compared with that of horses. Abdominocentesis and transabdominal ultrasound are useful tools in determining the necessity of an exploratory laparotomy. Preoperative anticipation of the lesion location helps determine the surgical approach to the abdomen. Perioperative management is vital to improve chances for survival. Timely surgical intervention for correctable gastrointestinal lesions is expected to minimize postoperative complications and improve outcomes.

Conformation and anatomical relations of the liver of llama (Lama glama).

Morphological studies of the liver of the llama are structural supportive to the clinical practice, surgery and specific diagnostic techniques. The aims of this study were first to determine the location of the organ and the direction of its major axis to project it to the abdominal wall, identifying visible and palpable bony references. Secondly, to characterize and determine anatomical relations of the surfaces, borders and angles of the llama liver, as well as, of its lobulation. Twenty adult llamas of both sexes and two foetuses of 6.5- and 7-month-old were used. Llama liver is a post-diaphragmatic organ located in the cranial abdominal region, in the right hypochondrium, in relationship with the last six ribs. Dorsally, it can exceeds the last (twelfth) rib. Its major axis presents a cranio-ventral bent. Its shape is irregularly triangular. It presents two surfaces (parietal and visceral), three borders (cranial, caudal and ventral) and three angles (dorsal, cranial and caudal).

Circuito venoso cervical de la llama (Lama glama) / Cervical venous circuit of the llama (Lama glama)

La particular estructura de la región cervical de la llama (Lama glama) se traduce en numerosas diferencias anátomo-funcionales respecto de otros mamíferos domésticos. Entre ellas merece destacarse un distintivo circuito venoso, cuya descripción es el objetivo de este trabajo. Para el presente estudio, se utilizaron diez llamas, machos, adultos y de aptitud lanera. Para resaltar las venas del cuello se procedió a la repleción de las mismas y, posteriormente, se disecaron los vasos utilizando técnicas e instrumental convencional. Se describe la morfología particular de un circuito venoso, en el cual las venas yugular externa, vertebral e intervertebrales son las principales protagonistas. El hecho destacado radica en las anastomosis establecidas entre las citadas venas, uniones dispuestas en forma metamérica, formando un circuito o by pass yugular-vertebral. La existencia de comunicaciones o shunts venosos, permite definir un circuito de circulación colateral derivando la sangre principalmente hacia la vena yugular externa. La longitud del cuello y los hábitos de pastoreo indican que esta disposición vascular es un hecho facilitador del retorno venoso, en cuanto a su dinámica y al control regional del flujo sanguíneo.

The neck region of the Llama (Lama glama) has several structural and functional particularities in comparison to the same region of other domestic mammals. Among them, it is noticeable a distinctive venous circuit whose description is the purpose of this study. In order to perform the study, the veins of the neck of ten adult, male, wool type llamas were dissected with conventional technique. Previously to dissection, the veins were filled with a repletive substance. The authors describe the morphology of a venous circuit in which external jugular vein (v. jugularis externa), vertebral vein (v. vertebralis), and intervertebral veins (vv. Intervertebrales) are the main participating vessels. The distinctive feature is the fact that the metameric anastomoses between the forenamed veins leads to a jugular-vertebral by pass. The existence of venous shunts provides a circuit of collateral circulation, diverting the blood mainly towards the external jugular vein. Grazing habits and the length of the neck suggest that the vascular structure previously described facilitates the venous return, contributing to the regional blood stream control.

The suspensory apparatus and digital flexor muscles of the llama (Lama glama) 1: The thoracic limb / El aparato suspensorio y los músculos flexores digitales de la llama (Lama glama) 1: El miembro torácico

The digital flexor muscles of the thoracic limb of four llamas were dissected and illustrated to provide data about the suspensory (support) apparatus and weight bearing structures. An extensive literature search was performed and yielded incomplete information about these anatomical structures. The popularity of the llama world wide as a domesticated animal used for show and fiber has increased in the recent years. It is helpful to describe the anatomy fully to aid in understanding of the species and treatment of pathologic conditions. The description of the anatomical structures and the original illustrations demonstrate genuine peculiarities and differences between the llama and domestic ruminants. In llamas, the three heads of the deep digital flexor muscle (DDF) originate and connect with each other in a very peculiar combination, with one tendon receiving an attachment from the flexor carpi ulnaris muscle (FCU). The superficial digital flexor muscle (SDF) has a thin tendon which is fused with the palmar fascia and then broadens. There are no interflexor muscles. Additionally, unexpected lumbricalis muscles are found in the distal limb and vary in number between the fore and hind limb. The anatomy of the suspensory apparatus in the thoracic limb is evaluated in this paper.

Fueron disecados e ilustrados los músculos flexores digitales del miembro torácico de cuatro llamas con la finalidad de aportar datos sobre el aparato suspensor (de apoyo) que soportan estas estructuras. Se realizó una extensa búsqueda bibliográfica dada la incompleta información existente de estas estructuras anatómicas. La popularidad de la llama en todo el mundo como uno de los animales domésticos utilizados ha aumentado en los últimos años. Es importante describir detalladamente la anatomía de esta especie para su tratamiento en condiciones patológicas. La descripción de las estructuras anatómicas y las ilustraciones originales demuestran peculariedades genuinas y diferencias entre la llama y los rumiantes domésticos. En llamas, las tres cabezas del músculo flexor profundo de los dedos se originan y se conectan entre ellas en una muy peculiar combinación, con uno de los tendones recibiendo un fascículo del músculo flexor ulnar del carpo. El músculo flexor superficial de los dedos tiene un tendón delgado el cual se fusiona con la fascia palmar y luego se amplía. No existen músculos interflexores. Adicionalmente, fueron encontrados músculos lumbricales en la extremidad distal y variaban en número entre los miembros. Finalmente, en este trabajo se evalúa el aparato suspensorio del miembro torácico.

The suspensory apparatus and digital flexor muscles of the llama (Lama glama) 2: The pelvic limb / El aparato suspensorio y los músculos flexores digitales de la llama (Lama glama) 2: El miembro pélvico

This paper provides data (text and illustrations) about the digital flexor muscles of the pelvic limb and the / metatarsophalangeal joint, evaluating the suspensory (support) apparatus and weight bearing structures. Similar to the above mentioned paper, a literature search provided incomplete information about these anatomical structures. As in the thoracic limb, unique anatomically variations exist in the pelvic limb of the llama. The caudal tibial muscle is fused with the lateral head of the deep digital flexor muscle (DDF), and the soleus muscle is missing. A symmetrical unexpected lumbricalis pedis muscle was found; the tendons are fusing with the axial branches of the lateral tendon of the long digital extensor muscle. A quadratus plantae muscle, also unexpected is present on the medial aspect of the tarsal region. The superficial digital flexor muscle (SDF) resembles that of the domestic ruminants. The metacarpo/ metatarsophalangeal joints, referred to as the fetlock joints (FJ) are very different from those of the domestic ruminants. Particular structures were found and they will be described and illustrated in the text. The anatomy of the suspensory (support) apparatus in the pelvic limb is evaluated in this paper.

El presente artículo ofrece datos (texto e ilustraciones) sobre el músculo flexor digital del miembro pélvico y la articulación metatarsofalángica, evaluando el aparato suspensorio (de apoyo) y el peso que soportan estas estructuras. La literatura proporciona información incompleta acerca de estas estructuras anatómicas. Al igual que en el miembro torácico, existen variaciones anatómicamente únicas en el miembro pélvico de la llama. El músculo tibial caudal se fusiona con la cabeza lateral del músculo flexor digital profundo (FDP), y el músculo soleo no existía. Fue encontrada una simetría inesperada del músculo lumbrical del pie; los tendones se encontraban fusionados con las ramas axiales del tendón lateral del músculo extensor digital largo. Un músculo cuadrado plantar, se encontraba presente en la cara medial de la región tarsal. El músculo flexor digital superficial (FDS) se asemeja al de rumiantes domésticos. Las articulaciones metacarpo/metatarsofalángicas, denominadas articulaciones del nudillo (AN) son muy diferentes de las de rumiantes domésticos. Fueron encontradas estructuras particulares que se describen e ilustran en el texto. Se evalúa la anatomía del aparato suspensorio (de apoyo) en el miembro pélvico.

Developmental changes at the materno-embryonic interface in early pregnancy of the alpaca, Lamos pacos.

This study analyses the manner in which trophoblast cells adhere to uterine epithelium and the subsequent interactions that contribute to the establishment of epitheliochorial placentation in the alpaca Lama pacos. Specimens at the luteal and follicular phases and at 22, 26, 30 and 45 days of pregnancy (op) were processed for morphological studies. On day 15 op, the blastocysts are completely free within the uterine lumen, with implantation starting around day 20. On days 22 and 26 of gestation, the trophoblast is apposed to the epithelial surface of the uterus, with areas of contact and adhesion by means of complex interdigitation. Implantation sites occur prevalently in the left uterine horn, but an expanded trophoblast also occupies large extensions of the right horn, where the maternofetal interaction shows peculiar areas of apposition. As development continues, attachment areas become more extensive. On days 30 and 45, many secretory granules can be seen in the uterine epithelium, while giant multinucleate cells appear interposed between the remaining trophoblast cells, showing intense alkaline phosphatase activity, deposits containing iron and PAS-positive granules. Placental lactogen hormone is not present within the cytoplasm of the binucleate or multinucleate trophoblast cells. By day 30 of gestation, the trophoblast layer is lined by an extraembryonic connective tissue that by day 45 is well vascularized, thus indicating the starting point of placental formation. Fetal and maternal capillaries indent the epithelium and the trophoblast, narrowing the specialized areas of exchange, which occur along the entire maternofetal interface, characterizing the diffuse nature of this placenta.

Placentation in the alpaca Lama pacos.

Reproduction in South American camelids is poorly studied. To extend our knowledge of the development and cellular physiology of the placenta in the alpaca Lama pacos, we have examined specimens from day 150 of pregnancy to term. Morphological investigations using light, transmission and scanning electron microscopy, the histochemical localization of iron, alkaline and acid phosphatase activity, and the immunodetection of placental lactogen hormone were performed. Throughout pregnancy there was a progressive increase in the depths of folds on the uterine mucosa surface together with a thickening of the endometrium. Glandular cells exhibited PAS and acid phosphatase (AcP) positive secretion granules. In the chorion, giant trophoblast polyploid cells gradually became more numerous and larger. Non-giant cells exhibited positive granules for PAS, alkaline phosphatase (AkP) reaction and immunostaining for bovine placental lactogen hormone (PLH). SDS -PAGE electrophoresis and Western blotting procedures also confirmed the presence of a bovine PLH-like glycoprotein in the fetal alpaca placenta. Over the glandular openings, the chorion formed typical areolae, where the trophoblast exhibited AcP and PAS positive reactions. At these sites, the fetal endothelial cells contained iron-storage granules in their cytoplasm. The trophoblast-epithelial interface exhibited a complex microvillous interdigitation, in which an AkP reaction was very prominent. The chorionic capillaries progressively indented adjacent trophoblast cells. These data suggest that although the epitheliochorial alpaca placenta is diffuse, various trophoblast cell types and specialized areas of the maternofetal interface give the placenta micro-regional functions where histiotrophic nutrition, hormone production and molecular exchange are prevalent.