Criollo Horses Research Articles

Avaliação da eficácia do uso de Ivermectina e Praziquantel associados em equinos da raça Crioula

The objective of this study was to evaluate the anthelmintic efficacy of the combination of the active principles Ivermectin and Praziquantel in naturally occurring Criollo horses. Feces were used of 68 adult animals of both sexes, raised in an extensive system and naturally infected with helminths. Samples were processed and analyzed by the technique of Gordon & Whitlock (1939) and the evaluation of the effectiveness of the association of active principles was based on the method of Coles et al. (1992). The Efficacy Index of treatment with the combination of Ivermectin and Praziquantel was 93,2%. Thus, it can be concluded that the association of the active principles used was effective in the treatment of endoparasite in the studied equine population.

Arthrographic Study of the Communication between the Tarsal Joints in Crioulo Horses.

The aim of the present study is to assess an arthrographic technique based on the access to the equine tarsus via distal intertarsal and on the existence and frequency of communication between distal and tarsocrural joints in the tarsus of Crioulo horses. Fifty Crioulo horses of both sexes from 3 to 8 years old were included in the experiment. Animals with radiographic signs of tarsal osteoarthritis and joint space loss were excluded from the experiment. Contrast was injected in the distal intertarsal joint and radiographs were taken at two different times - Time 0 (after contrast application) and Time 1 (45 seconds after) to detect any communication between tarsal joints. The recorded results were analysed through chi-squared test. Thirty out of three hundred tarsi were excluded from the experiment since the radiographic images showed loss of the distal intertarsal joint space. Positive contrast was injected in distal intertarsal joint of 70/100 tarsi. There was not any contrast overflow in the 30/70 assessed tarsi. Contrast diffused to the tarsometatarsal joint in 32/70 of the assessed tarsi and reached tarsocrural joints in 8/70 tarsi. The adopted arthrographic technique was effective in data collection and evaluation; however, 52/70 of tarsi showed contrast overflow to the bursa of the cunean tendon. The communication between tarsocrural and distal tarsal joints in Crioulo horses was significantly higher, and this finding emphasizes the importance of performing contrasted arthrography before getting to a final diagnostic and defining therapeutic procedures.

Ultrasonographic, macroscopic and histological characterization of the proximal insertion of the suspensory ligament in Crioulo horses

ABSTRACT: Although ultrasound (US) is a routine diagnostic modality, it still presents limitations for the diagnosis of lesions such as those in the proximal insertion of the suspensory ligament (PISL) because of its composition, which includes muscle fibers and adipose tissue interspersed with the ligament fibers. The objective of the present study was to describe the ultrasonographic, macroscopic and histological aspects of the PISL of thoracic limbs (TL) and pelvic limbs (PL) in Crioulo horses (CH). We selected 34 specimens of TL (right and left) and 10 specimens of PL of horses with a mean age of 5.7 years, from a private clinic or sent to the Department of Veterinary Pathology of UFSM, which died from different causes. The animals had no previous history of lameness in selected limbs associated with PISL injuries. The 34 specimens of PISL of TL were divided into CH (n=25) and Thoroughbred horses (TBH) (n=9), which composed the control group, and 11 specimens of PISL of PL were divided into CH (n=8) and TBH (n=3), which also served as control. The US examination was performed in the PISL using a Sonosite Edge device, 5-10 MHz linear transducer, with cross-sectional and longitudinal palmaromedial and palmarolateral images of the proximal surface of metacarpus III, II and IV (MCIII/MCII/MCIV). In PL, the evaluation was performed four centimeters below the chestnut in the plantaromedial aspect of metatarsus III and II (MTIII/MTII). PISL lobulated shape and size were compared with those of the contralateral limb, as well as the regularity of the palmar bone surface of MC III, II and IV. Subsequently, dissection of the PISL lobes was performed, as well as its macroscopic evaluation, which preceded the histological processing of the samples. In specimens of the CH breed, PISL showed echogenicity varying from peripheral dorsal hyperechogenic zones that merge into echogenic and hypoechogenic zones, where lobulation occurs. In the samples from the TBH group, PISL was also lobulated, but with differences in the echogenicity pattern such as diffuse hypoechogenicity and echogenicity. Macroscopically, CH samples presented a large amount of adipose tissue that corresponds to the dorsal peripheral zone of PISL, which ends in the connective tissue that delimits the ligamentous lobes. On a macroscopic cross-section of PISL, muscle fibers in red are mixed with white ligament fibers in the center of the ligament. This macroscopic finding was not observed in TBH samples, in which muscle fibers overlap ligament fibers throughout the ligament extension and a small amount of fat is present in the dorsal periphery of the ligament. PISL of PL had a triangular shape with echogenicity characteristics very similar to those observed in TL. In ultrasonographic, macroscopic and histological evaluation, PISL samples of TL and PL in CH showed a larger amount of peripheral dorsal adipose tissue, as well as a larger number of merged ligament and muscle fibers compared with those in TBH.

INDIVIDUAL AND MATERNAL ASPECTS OF ATHLETE CRIOULO HORSES

Freio de Ouro is a competition exclusively for Crioulo horses, officially promoted for over 30 years. Performance of equine athletes are correlated to maternal characteristics. This study aimed to describe individual and maternal aspects of athlete Crioulo horses that have won the Freio de Ouro competition. A retrospective study was performed with the data collected in the genealogical service of ABCCC, between the years 1982 and 2012. Data analyzed were the animals’ age at winning, maternal age at first parturition, maternal age at the winner’s parturition, and parturition order. Descriptive statistics were performed with a computer program. Mean age of winners was 7.1+0.17 years, 95.4% of the animals won between 4 and 11 years old and 3.2% after 12 years old. Mean maternal age at first parturition was 6+0.19, 53.6% of the females delivered before 5 years and, consequently, 46.4% at 6 years or over. Mean maternal age at parturition of the winners was 9.2+0.37 years. In the range between 5 and 8 years, 50.3% of the champions were born. Approximately 5.9% of mares delivered champions when 4 years or younger, whereas 15.6% delivered at over 15 years. Around 28% of the champions were born from primiparous mares, 53.7% from 2nd–5th birth, and 18.3% were from their dams’ 6th–12th delivery. The present study provides retrospective information regarding individual and maternal aspects of athlete Crioulo horses that have won the Freio de Ouro over the last 30 years.

Survey of dental diseases in Crioulo breed horses reared in an extensive farming system

ABSTRACT The present study aimed to identify and quantify dental diseases in Crioulo horses reared exclusively under extensive farming conditions. In total, 254 Crioulo horses were evaluated, that were reared exclusively in native pastures with predominantly Eragrostis plana (Annoni grass). The animals were divided into three groups according to age: three to five years (G1), six to 12 years (G2), and 13 to 26 years (G3). In total, 46.1% of the animals in G1, 63.8% in G2, and 82.3% in G3 had two or more incisor disorders; 37.5% in G1, 52.5% in G2 and 45.5% in G3 had two or more disease findings in the canines; and 28.9% in G1, 35.4% in G2, and 64.7% in G3 had four or more disease findings in the second, third, and fourth premolars and molars. However, dental calculus was observed in 90.5% of G2 animals, whereas in G3, the occurrence rate of excessive enamel points and calculus was 82.4%. Although all of the horses studied were reared in an extensive farming system, dental changes were very common in the Crioulo breed reared under these management conditions.

Differences in mineral concentrations on hooves of horses, mules and donkeys

This study aimed to measure the concentrations of minerals in different regions and pigmentation of horses’ hooves, mules and donkeys. A total of 20 Crioulo horses, 20 mules and 20 Pega donkeys were used. They formed two groups: pigmented (dark) or non-pigmented (bright) hooves. All animals were unshod and with adequate foot conformation. Females were nonpregnant and without foal and no animals were in training. Samples were collected from the hooves of all limbs in the regions of wall, sole and frog. The concentrations of calcium, magnesium, copper, iron and zinc were determined by atomic absorption spectrophotometry; sodium and potassium concentrations were determined by atomic emission spectrophotometry. Among the groups it was observed that the wall, sole and frog of donkeys’ hooves presented higher concentrations of sodium and calcium and with the exception of the frog that also obtained higher levels of copper in this species. Mules had lower concentrations of zinc in the wall and the horses had higher concentrations of potassium and zinc in the sole and higher magnesium in the frog and wall. There was no difference (P>0.05) in concentrations regarding the pigmentation of the hooves. The different regions of the hooves in each group presented similar concentrations of minerals and it was regardless of the pigmentation. The mineral concentrations may be related to desirable functional properties of the donkeys’ hooves. Pigmented and non-pigmented hooves have similar concentrations of minerals.

Notes on works for documenta 14, Athens & Kassel, 2017

ABSTRACTThis text details two inter-related Envoy works, Criollo and The Athens-Kassel Ride: The Transit of Hermes, commissioned for documenta 14, Athens and Kassel, 2017. Both works respond to Tschiffely’s Ride (1933), an account of a 10,000 mile journey from Buenos Aires to New York (1925–1928) by Swiss-Argentine horseman, Aimé Félix Tschiffely, riding two Argentine criollos, Mancha and Gato. The film Criollo features an Argentine criollo horse standing at the Artists’ Gate entrance to Central Park at the end of sixth Avenue / Avenue of Americas, New York. Criollo, a variant of ‘creole’, holds associations of ‘creolisation’, ‘cultural mixing’ (Hall) and ‘entanglement’ (Glissant) in the context of globalisation and migration. Criollo also prompts consideration of the animal in the development of capitalism (Berger, Raulff) and a reading, in turn, of the concepts of ‘bare life’, ‘bios’ and ‘zoe’ (Agamben). These contexts also frame The Athens-Kassel Ride: The Transit of Hermes, a 3000km equestrian journey performed over 100 days by four Long Riders traversing Greece, Macedonia, Serbia, Croatia, Slovenia, Austria and Germany, accompanied by a Greek arravani horse ‘Hermes’ named after the god of border crossings who – as angel messenger – is a key figure in the thought of Michel Serres.

Mensuração ultrassonográfica dos ligamentos colaterais da articulação interfalangeana distal de equinos da raça Crioula

Criollo horses were used in the past only for field services, especially countryside work. However, currently, they have been used as sports animals in several modalities involving turns in legs and exercises on irregular terrain, predisposing them to injuries in the distal extremity. Among the alterations recognized as cause of lameness in this region are the conditions related to collateral ligaments of the distal interphalangeal joint (CL-DIPJ), which in horses are structures that help to maintain joint stability and suffer a high pressure due to the high body weight, especially when it is not equally distributed at the stance phase. Considering the importance of the ultrasound anatomical knowledge of this structure for the early diagnosis of locomotive affections in the digit of Criollo horses, this study aimed to standardize CL-DIPJ measurements in healthy horses of this breed. We used 25 adult Criollo horses not submitted to sports practice. For ultrasonographic evaluation, after a trichotomy of the region, an ultrasound Chison 8300VET and a 6.0 MHz linear probe were used with a standoff pad. This technique uses a cross-sectional view, in which CL-DIPJ is visualized in the distal concavity portion of the middle phalanx, being a standard for the measurements. For ligament measurements, the variables dorsopalmar diameter (DPD), latero-medial diameter (LMD), and cross-sectional area (CSA) of ligaments were used. Three measurements were performed for each variable and average values were obtained, which were compared to each other and did not present significant differences (p > 0.05). The average measurements of diameter and area of collateral ligaments of the distal interphalangeal joint in Criollo horses were 9.04 mm for DPD, 7.55 mm for LMD, and 0.52 mm2 for CSA. This was the first study that standardized the size of this structure in this breed.

Association of morphometric measurements with morphologic scores of Criollo horses at Freio de Ouro: a path analysis

ABSTRACT This study used path analysis to establish the direct, indirect, and total effects of body linear and angular measurements on subjective morphological scores of the 247 Criollo horses that participated in their most important performance event, Freio de Ouro, in 2012. Freio de Ouro is the only event of the Criollo breed that considers morphology. Measurements of wither height, thoracic girth, cannon bone girth, body length, metatarsus length, croup length, shoulder width, head length, neck length, and upper neck [...]

Biometric evaluation of Criollo horses participating in the Freio de Ouro competition, Brazil

ABSTRACT The objective of this study was to quantify linear and angular morphological measurements of male and female horses participating in the Freio de Ouro competition. This study represents the first scientific evaluation of the biometrics of the Criollo breed, providing essential information for the evaluation of the development of the breed and supporting objective selection. We examined linear and angular measurements of 634 Criollo horses participating in the Freio de Ouro competition in 2011 and 2012, including height, chest [...]

Genetic parameter estimation for long endurance trials in the Uruguayan Criollo horse.

The aim of this study was to estimate the genetic parameters of performance in a 750-km, 15-day ride in Criollo horses. Heritability (h2 ) and maternal lineage effects (mt2 ) were obtained for rank, a relative placing measure of performance. Additive genetic and maternal lineage (rmt) correlations among five medium-to-high intensity phase ranks (pRK) and final rank (RK) were also estimated. Individual records from 1,236 Criollo horses from 1979 to 2012 were used. A multivariate threshold animal model was applied to the pRK and RK. Heritability was moderate to low (0.156-0.275). Estimates of mt2 were consistently low (0.04-0.06). Additive genetic correlations between individual pRK and RK were high (0.801-0.924), and the genetic correlations between individual pRKs ranged from 0.763 to 0.847. The pRK heritabilities revealed that some phases were explained by a greater additive component, whereas others showed stronger genetic relationships with RK. Thus, not all pRK may be considered as similar measures of performance in competition.

Efecto del medio extensor y de las curvas de enfriamiento y congelamiento en la célula espermática en caballos criollos colombianos

El objetivo fue analizar los parámetros de motilidad, vigor, morfología e integridad de membrana plasmática para cada uno de los crioprotectores. Cada eyaculado se dividió en dos alícuotas iguales al azar con variaciones en la adición del crioprotector (dimetilformamida 5% o glicerol 5%) y se congelo por el protocolo de criopreservación, con una curva de enfriamiento de 5ºC durante 120 minutos y exposición a vapor de nitrógeno durante 15 minutos antes de ser sumergido al nitrógeno líquido. La viabilidad espermática (motilidad) fue evaluada mediante el test de termorresistencia, la morfología de las células se evalúo fijando el semen en formol salino y la integridad de la membrana plasmática de la cola del espermatozoide mediante el test hiposmótico. Al evaluar el semen pos descongelación no se observó diferencia significativa (p> 0.05) entre los dos crioprotectores respecto a los parámetros evaluados. Los resultados nos permiten concluir que la utilización del medio extensor INRA 82 modificado con azúcares asociado a leche descremada con adición del 2% de yema de huevo, y a una curva de enfriamiento moderada de 120 minutos a 5ºC muestran efectos benéficos en los parámetros espermáticos pos descongelamiento de forma independiente al crioprotector utilizado en los caballos criollos colombianos.

Growth Curve of Crioulo Foals from Birth until 24 Months of Age

Background: Breeding of Crioulo horses in the southern region of Brazil is very significant. Notwithstanding, not all animals meet the standards defined for the breed, raising concern among breeders, owners and veterinarians, driving them to an effort to know and understand the development of Crioulo foals. In order to get a registry at Brazilian Association of Crioulo Horse Breeders (ABCCC), the foals must be presented to a certified technician as of 24 months of age and show the breed standards and measurements required. To date, there are no data concerning development of this breed available. Therefore, this study aims to describe the growth curve of Crioulo foals in the south region of Rio Grande do Sul.Materials, Methods & Results: The study was conducted in three Crioulo horse breeding farms in the cities of Santa Vitória do Palmar, Bagé and Aceguá, in the state of Rio Grande do Sul, Brazil, for a period of two years (2013-2015). We followed up on 267 Crioulo foals from birth up to 24 months of age. Biometric evaluation was divided in 26 periods, with 40 animals in each and random repetition of individuals. Period one: birth to seven days; period two: seven to 21 days; monthly from 1st to 24th month. The three breeding farms presented similar environmental conditions and the horses were submitted to similar management. Measurements were taken on a monthly basis, using a mechanical scale for weight and a hippometer for height. The analysis were conducted on SAS/ETS® version 9.2. Logistic non-linear regression model was used to obtain growth curves for height and minimum, medium and maximum weight of the foals on their respective ages, by this way six growth curves were produced. Results show an increase in weight and height at 24 months of age compared to the moment of birth. This increase was accentuated during the first months of life, both in weight and height. Thus, it is possible to observe that the first six months of life is characterized by a larger growth rate and is therefore, essential for the foals development, requiring special attention from the breeder and owner.Discussion: The growth curve obtained show that not all individuals reach the measurements required by the breed’s association, corroborating the empirical observation of breeders and technicians in their routine. This is also a concern related to other Brazilian breeds such as Mangalarga Marchador, Pantaneira, Campeira. For the mentioned breeds, the adequate growth curve has already been described aiming to controlling foal development. The ABCCC require that foals as of 24 months of age have the minimum values of 1.40 m 1.38 m and 1.38 m; and maximum values of 1.50 m, 1.48 m and 1.50 m, for males, females and geldings, respectively, in order to receive the Association brand and the permanent registry. According to the growth curve, the first two months of the foal’s life show the largest growth rate, reaching 78.4% of an adult’s height with average growth of 20 cm, reaching 1.05 m. Genetic features, nutritional and sanitary conditions, directly influence this period. Overweight associated to exercising increases the risk of musculoskeletal injury and represent a factor for stress on the joints. This should be a concern among Crioulo breeders and the knowledge of their growth curve is important for an objective assessment seeking for a gradual and weighted development. In this work, it was possible to determine the growth curve of Crioulo breed foals in the south region of Rio Grande do Sul, from birth up to 24 months of age, providing minimum, medium and maximum parameters referring to withers height and body weight.

Evaluation of oral sugar test response for detection of equine metabolic syndrome in obese Crioulo horses

Owing to the high prevalence of obesity in Crioulo horses, information allowing early diagnosis of equine metabolic syndrome (EMS) and prevention of the associated laminitis is of great value. The aim of this study was to evaluate the occurrence of EMS and the response to an oral sugar test (OST) in obese Crioulo horses. Twenty-two Crioulo horses were allocated into 3 groups according to their body condition score (BCS out of 9) and presence or absence of laminitis as follows: CON (6/22), BCS < 7; OB (8/22), BCS ≥ 7; and LAM (8/22), BCS ≥7 with clinical and/or radiographic signs of laminitis. A complete clinical history was obtained, followed by a physical examination, morphometric measurements, radiographic evaluation of front feet, and ultrasonography measurements of subcutaneous body fat. For the OST, animals were fasted overnight, and blood samples were collected for glucose and insulin concentration before and after sugar administration. Morphometric and metabolic differences (P < 0.05) were observed between CON animals and obese ones, with horses from the LAM group presenting the highest morphometric measurements and insulin plasma concentrations. A delayed peak glucose response for OST was observed in the majority of obese animals, indicating that sampling between 60 and 90 min after sugar administration without glycemic curve follow-up, as previously used for hyperinsulinism detection, can be inadequate. The observed delay in the return to glucose baseline levels, combined with high insulin levels, supports the diagnosis of insulin dysregulation. These results indicate that there are clear obesity-related differences in the glucose and insulin responses of Crioulo horses to an OST.

Diversidad Genética del Caballo Criollo (Equus caballus) mediante Genes Asociados al Pelaje en Valencia, Colombia

El objetivo de este trabajo fue estudiar la variabilidad genética de caballos criollos (Equus caballus) mediante genes asociados al pelaje. Se realizaron muestreos entre enero y mayo de 2016 en cinco poblaciones de la ciudad de Valencia. Se realizó la caracterización fenotípica de los animales adultos presentes en las fincas, atendiendo a los marcadores autosómicos de codificación morfológica Extension, Agouti, Cream, Gris, White, Tobiano, Overo y Roan. Los resultados mostraron ausencia de los marcadores White y Overo, mientras que los marcadores Extension y Agouti fueron los de mayores frecuencias, posiblemente favorecidas por selección artificial, debido a temperamento y astucia respectivamente. Las poblaciones se encontraron en equilibrio de Hardy-Weinberg, exhibieron exceso de homocigotos y altos valores de flujo genético.

Enterolitíase em equinos da raça crioula

Enteroliths are intestinal mineral calculi predominantly composed of struvite. In horses this material accumulates concentrically around a core, causing total or partial obstruction of the higher and lower colon, and can lead to death by rupture. The enterolithiasis has worldwide distribution, and occurs frequently in Rio Grande do Sul, especially in Crioulo Horses. The aim of this work is to report a sequence of cases of Crioulo Horses with enterolithiasis, linking risk factors through historical analysis, clinical presentation and management employed by the breeding farms. Case: Between the years 2012 and 2015, 16 Crioulo Horses with colic syndrome caused by enteroliths were treated at the Hospital de Clínicas Veterinária of Universidade Federal de Pelotas (UFPel), RS, Brazil and Clínica Hípica, in Porto Alegre, RS. The group was formed predominantly by males, weighted 430 kg in average and the average age was eight years old. All horses underwent general and specific clinical examination, laboratory tests and surgical procedure to remove the enterolith. After discharge, there was an epidemiological questionnaire seeking information about the history, food and environmental management that could be related to the development of enterolithiasis. In relationship to the history of previous episodes of colic, the results were: 4 horses (25%) had no previous episodes of colic, while 12 horses (75%) had experienced previous colic. Regarding the horses’ bedding, 70% use sawdust and 30% rice husk, and about behavior, ten (62.5%) of the 16 horses attended had no stereotypies. Related to food and water supply, it was observed that nine horses (56.25%) had alfalfa as the only roughage source in the diet, and all animals (100%) were fed commercial food and water ad libitum. According to the number of hours the patients remained stabled, the rearing system was classified as intensive (over 12 h/stable/day), extensive (0 h, at the field) or semi-extensive (up to 12 h/stable/day). The frequencies observed were: intensive (9 animals - 56.25%), semi-intensive (6 animals - 37.5%) and extensive (1 animal - 6.25%). The average time of stabling was 17.2 h/day. Discussion: The alfalfa consumption as the only forage observed in our study is the main risk factor described for the formation of enteroliths. This is because in digestion, alfalfa tends to alkalize the intestinal pH, hindering the metabolism of some minerals and thus forming the enterolith. Another important risk factor observed in this work is the intensive rearing, with long periods of stabling. This explains why confinement leads to decreased intestinal motility, due to reduced or absent grazing. Furthermore, reduced physical activity is another contributing factor to the reduction of motility, because the exercise influence the intestinal peristalsis. The rearing of horses intensively is usual with the Crioulo, especially in training and morphological preparation. Based on this case study, we can’t say that there is a racial predisposition to enterolithiasis of the Crioulo Horse, since it would require more studies on the physiology and a standard feeding of these horses. However, we can attribute the considerable volume of enteroliths observed in Crioulo Horses in Rio Grande do Sul to the increase in the number of referrals to the reference hospitals, feeding alfalfa as the only roughage source in the diet and to intensive management of the farms, with long periods of daily stabling.

The legacy of Columbus in American horse populations assessed by microsatellite markers

Criollo horse populations descend from horses brought from the Iberian Peninsula over the period of colonization (15th to 17th century). They are spread throughout the Americas and have potentially undergone genetic hybridization with other breeds in the recent past. In this study, 25 autosomal microsatellites were genotyped in 50 horse breeds representing Criollo populations from 12 American countries (27 breeds), breeds from the Iberian Peninsula (19), one breed each from France and Morocco and two cosmopolitan horse breeds (Thoroughbred and Arabian). The genetic relationships among breeds identified five clusters: Celtic; Iberian; North American with Thoroughbred influence; most Colombian breeds; and nearly all other Criollo breeds. The group of "all other Criollo breeds" had the closest genetic relationship with breeds originating from the Iberian Peninsula, specifically with the Celtic group. For the whole set of Criollo breeds analysed, the estimated genetic contribution from other breeds was approximately 50%, 30% and 20% for the Celtic, Iberian and Arab-Thoroughbred groups, respectively. The spatial distribution of genetic diversity indicates that hotspots of genetic diversity are observed in populations from Colombia, Ecuador, Brazil, Paraguay and western United States, possibly indicating points of arrival and dispersion of Criollo horses in the American continent. These results indicate that Criollo breeds share a common ancestry, but that each breed has its own identity.

Análisis biométrico del caballo Criollo Araucano

En este estudio se determina el grado de relación existente entre diferentes variables corporales en 52 machos Criollo Araucano, mediante un análisis de componentes principales. Los caracteres corporales empleados fueron 20: perímetro torácico, diámetro longitudinal, diámetro dorso-esternal, alzada a la cruz, diámetro bicostal, altura del espacio subesternal, anchura de pecho, perímetro de la caña anterior, longitud de cabeza, anchura de cabeza, longitud de cráneo, anchura de cráneo, longitud de cara, anchura de cara, profundidad de la cabeza, alzada a la grupa, largo de grupa, anchura de grupa, altura al nacimiento de la cola y altura al corvejón. Se analizaron igualmente las posibles diferencias morfológicas entre cuatro fincas de la zona. Del estudio puede concluirse que la población de caballos criollos araucanos, aunque bastante uniforme, presenta diferencias morfológicas entre fincas, siendo estas diferencias de aspecto general más que centradas en regiones corporales determinadas.

Morphometric changes in the hoof capsule of Criollo foals from birth to weaning

ABSTRACT: South America has numerous Criollo horse breeding farms; however, information on foal hoof growth is still limited and identifying the ideal periods to apply corrective trimming is a frequent concern for horse owners. In the present study, a morphometric analysis of hoof growth was performed on 46 Criollo foals from birth to weaning (0-8 months). Results showed that hoof growth rate was higher in the first four months followed by a decrease until the eighth month. Average growth rate of the hoof was 0.21cm per month, whereas that of the heel was 0.14cm per month. However, no significant differences were observed between medial and lateral heel length or between limbs. Coronary band perimeter and solar width showed an average increase of 0.97cm and 0.46cm per month, respectively, and were significantly correlated (r=0.99, P≤0.01). The characteristic most positively correlated to biometric variables was foal age, followed by solar width, toe length, and coronary band perimeter. In conclusion, hoof length increase in Criollo foals was more intensive during the first four months of life.

Morphology and Morphometry of Seminiferous Tubules in Crioulo Horses

This study aimed to assess the biometrics of the testes and the morphology of the seminiferous tubules of Crioulo horses. We studied 10 sexually mature stallions (3–6 years of age). After orchiectomy, testes were perfused with Karnovsky's solution and then embedded in glycol methacrylate. Testis sections (4 μm) were cut and stained with toluidine blue and a solution of 1% sodium borate. The histological images were digitized, and the morphometric analysis was performed using ImageJ software. The average weight of the stallions was 377.5 kg, and the average weight of both testicles was 162.9 g. The percentage of testicular parenchyma occupied by the seminiferous tubules and the intertubular tissue was 77.97% ± 6.34% and 22.03% ± 6.34%, respectively. The average tubular diameter was 205.00 ± 36.91 μm, whereas the average height of the seminiferous epithelium was 70.56 ± 2.82 μm. Average tubular length per testicle and average tubular length per gram of testicle were 4,085.10 ± 1,170.68 m and 26.09 ± 10.63 m/g, respectively. The characteristics of the eight stages of the seminiferous epithelium cycle were similar to those reported in other horse breeds. We conclude that the morphometry of the seminiferous tubules of Crioulo horse resembles what has been reported in other horse breeds. The volumetric proportion of the seminiferous tubules and the Leydig cells of the Crioulo horse is one of the highest ever reported for stallions.