Estudio observacional de las características clínicas, epidemiológicas y de laboratorio en pacientes pediátricos con dengue de la ciudad de Córdoba / Observational study of clinical, epidemiological, and laboratory characteristics of pediatric patients with dengue in the city of Córdoba

Introducción. El dengue es la enfermedad transmitida por mosquitos con mayor propagación mundial en los últimos años. Presenta un amplio espectro de manifestaciones clínicas y, en ocasiones, evoluciona a un estado crítico llamado dengue grave. Su tratamiento es de sostén. La información disponible acerca de las características clínicas, epidemiológicas y de laboratorio de la enfermedad en la población pediátrica es limitada. Objetivo. Describir la epidemiología y las manifestaciones clínicas y de laboratorio de la enfermedad. Población y métodos. Estudio descriptivo, observacional y retrospectivo. Incluyó pacientes entre 1 y 180 meses asistidos por dengue probable o confirmado en un hospital de niños, desde el 01 de enero de 2020 hasta el 31 de mayo de 2020. Resultados. Se incluyeron 85 pacientes por criterios microbiológicos de positividad o clínicoepidemiológicos. Veinticinco (29 %) confirmados por RT-PCR, todos serotipos DENV-1. La mediana de  edad fue de 108 meses (rango intercuartílico: 84-144). Las principales manifestaciones clínicas fueron fiebre, cefalea y mialgias. Los hallazgos de laboratorio más importantes fueron leucopenia, trombocitopenia y elevación de transaminasas. Conclusión. El reconocimiento y la comprensión de las alteraciones clínicas y de laboratorio que se presentan durante la enfermedad pueden permitir un abordaje eficaz y contribuir a la reducción de cuadros clínicos más graves en los niños.

Introduction. Dengue has been the most widespread mosquito-borne disease worldwide in recent years. It develops with a broad spectrum of clinical manifestations and sometimes progresses to a critical condition known as severe dengue. It is managed with supportive treatment. Available information about its clinical, epidemiological, and laboratory characteristics in the pediatric population is limited. Objective. To describe the clinical, epidemiological, and laboratory characteristics of dengue. Population and methods. Descriptive, observational, and retrospective study. It included patients aged 1 to 180 months seen due to probable or confirmed dengue at a children's hospital between 1/1/2020 and 5/31/2020. Results. A total of 85 patients with positive microbiological or clinical-epidemiological criteria were included. Of these, 25 (29%) were confirmed by RT-PCR; all corresponded to DENV-1 serotype. Patients' median age was 108 months (interquartile range: 84­144). The main clinical manifestations were fever, headache, and myalgia. The most important laboratory findings were leukopenia, thrombocytopenia, and high transaminase levels. Conclusion. The recognition and understanding of clinical and laboratory alterations that occur during dengue disease may allow an effective approach and help to reduce the more severe clinical form in children.

Meningitis por Aeromonas complejo hydrophila productora de carbapenemasa: a propósito de un caso / Meningitis due to carbapenemase-producing Aeromonas hydrophila: a case report

Se describe una presentación clínica inusual de infección por Aeromonas complejo hydrophila y se destaca la importancia del correcto diagnóstico microbiológico para adecuar el tratamiento. Paciente de 6 años consultó por fiebre y drenaje de líquido serohemático de herida quirúrgica por antecedente de craneotomía con duroplastia la semana previa. Laboratorio con parámetros normales y tomografía computada sin cambios relevantes. Punción lumbar: leucocitos 91/mm3, proteínas 89 mg/dl, glucosa 36 mg/dl. Comenzó tratamiento con vancomicina y ceftazidima. Cultivo de líquido cefalorraquídeo: bacilo gramnegativo, oxidasa positivo, fermentador de glucosa. Se rotó a meropenem. A las 72 horas, se informó, por método difusión y Vitek2, Aeromonas complejo hydrophila: sensible a trimetoprimasulfametoxazol, ciprofloxacina, cefotaxima y meropenem. Se realizó método Blue Carba para detección de carbapenemasas con resultado positivo. Se rotó a trimetoprima-sulfametoxazol. Completó 21 días de tratamiento con evolución clínica favorable

Here we describe an unusual clinical presentation of infection due to Aeromonas hydrophila and underline the importance of a correct microbiological diagnosis for an adequate treatment. A 6-year-old patient with a history of craniotomy with duraplasty the week before consulted for fever and drainage of serosanguineous fluid from the surgical wound. The laboratory parameters were normal and the computed tomography scan showed no relevant changes. Lumbar puncture: leukocytes: 91/mm3; proteins: 89 mg/dL; glucose: 36 mg/dL. Treatment with vancomycin and ceftazidime was started. Cerebrospinal fluid culture: oxidase-positive, glucose-fermenting Gram-negative bacillus. Treatment was changed to meropenem. At 72 hours, using a diffusion method and Vitek 2, it was reported as Aeromonas hydrophila sensitive to trimethoprim-sulfamethoxazole, ciprofloxacin, cefotaxime, and meropenem. The Blue-Carba method was performed to detect carbapenemases; the result was positive. Treatment was changed to trimethoprimsulfamethoxazole. The patient completed 21 days of treatment with a favorable clinical course.

Estudio multicéntrico de casos confirmados de COVID-19: datos preliminares de 2690 pacientes pediátricos en Argentina durante el primer año de la pandemia / A multicenter study of confirmed COVID-19 cases: preliminary data on 2690 pediatric patients in Argentina during the first year of the pandemic

Introducción. La evidencia actual indica que la gravedad de la enfermedad por el coronavirus 2019 (COVID-19, por su sigla en inglés) es menor en la población pediátrica, los datos locales aún son limitados. Objetivo: caracterizar los aspectos clínicos y epidemiológicos de la infección por COVID-19 en menores de 18 años en Argentina. Población y métodos. Estudio transversal, observacional y analítico de casos confirmados de COVID-19 entre 0 y 18 años asistidos entre marzo de 2020 y marzo de 2021 en 19 centros pediátricos de referencia de Argentina. Se realizó un análisis multivariado para identificar las variables predictoras de cuadros graves. Resultados. Se incluyeron 2690 casos de COVID-19: 77,7 % residentes del área metropolitana de Buenos Aires, 50,1 % de sexo masculino, mediana de edad de 5,6 años. El 90 % ocurrió entre las semanas epidemiológicas 20-47 del 2020; 60,4 % con antecedente de contacto con personas con COVID-19; y 96,6 % en el entorno familiar. El 51,4 % presentó síntomas respiratorios; 61,6 % síntomas generales; 18,8 % síntomas gastrointestinales; 17,1 % síntomas neurológicos; 7,2 % otros y 21,5 % fueron asintomáticos. El 59,4 % fue hospitalizado; 7,4 fueron graves o críticos. Se registraron 57 casos de síndrome inflamatorio multisistémico. El antecedente de asma, displasia broncopulmonar, cardiopatía congénita, desnutrición moderada a grave, obesidad, enfermedad neurológica crónica y/o edad menor de 6 meses resultaron predictores independientes de gravedad. Residir en barrios vulnerables resultó protector. Conclusiones. Más de la mitad de los casos refirieron antecedente de contacto con personas con COVID-19 en el entorno familiar. La hospitalización no respondió a criterios clínicos de gravedad. La gravedad se encuentra asociada a la existencia de ciertas comorbilidades.

Introduction. The current evidence indicates that the severity of the coronavirus disease 2019 (COVID-19) is lower in the pediatric population but local data are still limited. Objective: To characterize the clinical and epidemiological aspects of COVID-19 infection in patients younger than 18 years in Argentina. Population and methods. Cross-sectional, observational, and analytical study of confirmed COVID-19 patients aged 0-18 years seen between March 2020 and March 2021 at 19 referral children's hospitals of Argentina. A multivariate analysis was done to identify predictors of severe cases. Results. A total of 2690 COVID-19 cases were included: 77.7% lived in the Metropolitan Area of Buenos Aires; 50.1% were males; patients' median age was 5.6 years. Of them, 90% were seen during epidemiological weeks 20-47 of 2020; 60.4% had a history of contact with COVID-19 patients; and 96.6% in their family setting. Also, 51.4% had respiratory symptoms; 61.6%, general symptoms; 18.8%, gastrointestinal symptoms; 17.1%, neurological symptoms; 7.2%, other symptoms; and 21.5% were asymptomatic. In addition, 59.4% of patients were hospitalized and 7.4% had a severe or critical course. A total of 57 patients developed multisystem inflammatory syndrome. A history of asthma, bronchopulmonary dysplasia, congenital heart disease, moderate to severe malnutrition, obesity, chronic neurological disease and/or age younger than 6 months were independent predictors of severity.Livinginavulnerableneighborhoodwas a protective factor. Conclusions. More than half of cases referred a history of contact with COVID-19 patients in the family setting. Hospitalization was not based on clinical criteria of severity. Severity was associated with the presence of certain comorbidities

Repetitive DNAs and shrink genomes: A chromosomal analysis in nine Columbidae species (Aves, Columbiformes)

Abstract An extensive karyotype variation is found among species belonging to the Columbidae family of birds (Columbiformes), both in diploid number and chromosomal morphology. Although clusters of repetitive DNA sequences play an important role in chromosomal instability, and therefore in chromosomal rearrangements, little is known about their distribution and amount in avian genomes. The aim of this study was to analyze the distribution of 11 distinct microsatellite sequences, as well as clusters of 18S rDNA, in nine different Columbidae species, correlating their distribution with the occurrence of chromosomal rearrangements. We found 2n values ranging from 76 to 86 and nine out of 11 microsatellite sequences showed distinct hybridization signals among the analyzed species. The accumulation of microsatellite repeats was found preferentially in the centromeric region of macro and microchromosomes, and in the W chromosome. Additionally, pair 2 showed the accumulation of several microsatellites in different combinations and locations in the distinct species, suggesting the occurrence of intrachromosomal rearrangements, as well as a possible fission of this pair in Geotrygon species. Therefore, although birds have a smaller amount of repetitive sequences when compared to other Tetrapoda, these seem to play an important role in the karyotype evolution of these species.

Leishmaniasis visceral: Caso clinico pediatrico / Visceral leishmaniasis: Pediatric case report

La leishmaniasis es una enfermedad causada por parásitos obligados intracelulares pertenecientes al género Leishmania y que reconoce tres formas clínicas principales: cutánea, visceral y mucocutánea. Es una patología del grupo de las "enfermedades desatendidas". Es la única enfermedad tropical transmitida a través de vectores que se ha mantenido endémica por décadas en el sur de Europa. La leishmaniasis visceral representa la forma más grave. Se caracteriza por fiebre, pérdida de peso, anemia y hepatoesplenomegalia. Su período de incubación oscila entre 2 semanas y 18 meses. La leishmaniasis se considera una enfermedad reemergente a nivel mundial. Algunos de los factores que favorecen esta situación son los cambios en las condiciones climáticas, migraciones y urbanizaciones deficitarias en saneamiento ambiental. Se presenta el caso de un niño europeo que estaba vacacionando en Córdoba y fue derivado a nuestro Hospital por fiebre y pancitopenia, lo que generó un abordaje multidisciplinario con resolución clínica favorable.

Leishmaniasis is a disease caused by obligate intracellular parasites of the genus Leishmania. There are three main clinical forms of leishmaniasis: cutaneous, visceral and mucocutaneous. It belongs to the diverse group of the tropical "neglected diseases" and is the only tropical vector-borne disease that has remained endemic to southern Europe for decades. Visceral leishmaniasis represents the most serious clinical syndrome. It is characterized by fever, weight loss, anemia and enlargement of the spleen and liver. Incubation period is usually from 2 weeks to 18 months. Leishmaniasis is considered a worldwide reemerging disease. Some of the factors that favor this situation are the changes in the climatic conditions, migrations and urbanizations deficient in environmental sanitation. We report an interesting case of an European child who was spending holidays in Cordoba and presented to our hospital with fever and pancytopenia, motivating a multidisciplinary approach with favorable clinical outcome.

Pancreatitis aguda grave e infección por el virus de la influenza A (H1N1) en un paciente pediátrico: reporte de caso / Severe acute pancreatitis and infection by influenza A (H1N1) virus in a child: case report

La pancreatitis aguda (PA) es una enfermedad inflamatoria del páncreas caracterizada por dolor abdominal y niveles elevados de enzimas pancreáticas. Representa la enfermedad pancreática más común de niños y adultos. Para el diagnóstico, se requieren 2 de los siguientes 3 criterios: dolor abdominal característico de PA, valores séricos de amilasa y/o lipasa 3 veces mayores que el límite superior normal y hallazgos característicos en las imágenes. Múltiples etiologías se han asociado: traumatismos, enfermedades metabólicas e infecciones (mixovirus, VIH, parotiditis, coxsackie, hepatitis B, A, citomegalovirus, varicela, herpes simple). Existen solo 3 casos reportados de PA asociados al virus de la influenza H1N1, solo uno en un niño y de características no complicadas.

Acute pancreatitis is an inflammatory disease of the pancreas, characterized by abdominal pain and high level of pancreatic enzymes. Pancreatitis is the most common disease of pancreas in children and adults. For the diagnosis we need 2 of 3 characteristics: abdominal pain characteristic of acute pancreatitis, amylase and/or lipase 3 times higher than the normal upper limit and characteristic findings in images. The etiologies are multiple: trauma, metabolic disease and infections: mixovirus, HIV, measles, coxsackie, hepatitis B, C, cytomegalovirus, varicella, herpes simplex. Three cases of PA associated with H1N1 Influenza virus were reported, only one in a child with uncomplicated features.

Inferência bayesiana aplicada à estimação de herdabilidades dos parâmetros da curva de crescimento de fêmeas da raça Nelore / Bayesian inference applied to the estimation of heritability of growth curve parameters of Nellore females

Objetivou-se estimar parâmetros genéticos, utilizando inferência Bayesiana, para as estimativas dos parâmetros individuais de peso à maturidade (Â) e taxa de crescimento (K), obtidos pela função de crescimento Brody. O arquivo estava constituído de 14.563 registros de pesos e idades referentes a 1.158 fêmeas da raça Nelore, participantes do Programa de Melhoramento Genético da Raça Nelore. Para a análise das estimativas dos parâmetros da curva, via inferência bayesiana, foi proposto um modelo animal unicaráter, que incluiu como fixo o efeito de grupo contemporâneo (animais nascidos no mesmo estado, no mesmo trimestre do ano, mesmo ano e mesmo regime alimentar) e como aleatórios os efeitos genético direto e residual. Nessa análise, foram utilizados dois diferentes tamanhos para as cadeias geradas pelo algoritmo de amostragem de Gibbs, de 550 e 1.100 mil ciclos, com períodos de descarte amostral de 50 e 100 mil ciclos, respectivamente, e amostragens a cada 500 e 1.000 ciclos, respectivamente. As médias posteriores da variância genética aditiva e residual foram próximas, tanto para  quanto para a K, mesmo quando implementados diferentes tamanhos para as cadeias geradas pelo algoritmo de amostragem de Gibbs. Os coeficientes de herdabilidade estimados para Â, variaram de 0,44 a 0,46, amplitude semelhante aos 0,46 a 0,48 obtidos para as estimativas de K. Essas magnitudes indicam que a seleção pode ser usada como instrumento para alterar a forma da curva de crescimento desses animais. Entretanto, o uso das informações obtidas, visando à alteração da curva de crescimento dos animais, deve ser feito com grande cautela, uma vez que as características a serem trabalhadas na modificação do formato da curva de crescimento, de acordo com resultados da literatura especializada, são negativamente correlacionadas.

The objective of this study was to estimate genetic parameters using Bayesian inference for the estimates of individual parameters of mature weight (Â) and growth rate (K), obtained by Brody growth function. The file consisted of 14,563 records relating to weights and ages of 1,158 Nelore females, participants in the Genetic Improvement Program of the Nellore. For the estimates analysis of the curve parameters via Bayesian inference, it was used an univariated animal model that included as fixed effect of contemporary group (animals born on the same state, in the same quarter of the year, the same year and feedlot) and random as the direct genetic and residual. In this analysis it was used two different sizes for the chains generated by Gibbs sampling algorithm, 550 and 1.1 million cycles, with initial discarding of 50 000 and sample of 100 000 cycles, respectively, and sampled every 500 cycles and 1000, respectively. The mean posterior and residual additive genetic variance showed a small variation to both  and K, even when implemented in different sizes for the chains generated by Gibbs sampling algorithm. The heritability estimates for Â, ranged from 0.44 to 0.46, similar to the range 0.46 to 0.48 obtained for the estimates of K. These magnitudes indicate that the selection can be used as a tool to change the shape of the growth curve of these animals. However, the use of the information to amend the growth curve of animals, must be done with great care, since the traits to be worked in the modification of the shape of the growth curve according to the literature results are negatively correlated.

Classical nonlinear models to describe the growth curve for Murrah buffalo breed / Modelos não-lineares clássicos para descrever a curva de crescimento de búfalos da raça Murrah

With the objective of to adjust nonlinear models for the growth curves for a buffaloes herd raised in floodable lands in Rio Grande do Sul state, monthly records measured from birth to two years-old of 64 males and 63 females born between 1982 and 1989 were used. The models used were: Von Bertalanffy, Brody, Gompertz and Logistic. The parameters were estimated by NLIN procedure and the criteria used to evaluate the adjustment given by the models were: asymptotic standard deviation; coefficient of determination; average absolute deviation of residues and asymptotic index. Von Bertalanffy and Brody models overestimated the male asymptotic weight (A) in 15.9 and 171.3kg, respectively, and the Gompertz and Logistic models underestimated it in 4.5 and 13.4kg, respectively. For females, the Logistic model underestimated the asymptotic weight (-2.09kg), and Gompertz, Von Bertalanffy and Brody overestimated this parameter in 8.04, 17.7, and 280.33kg, respectively. The biggest average deviation was estimated by Brody model for both sexes, characterizing the biggest index. Considering the criteria, it is recommended the Gompertz and Logistic models for adjust females and males Murrah buffaloes breed growth curves.

Com o objetivo de ajustar modelos não-lineares ao crescimento ponderal para búfalos criados em terras baixas no Estado do Rio Grande do Sul, foram utilizados registros mensais mensurados do nascimento aos dois anos de idade de 64 machos e 63 fêmeas, nascidos no período de 1982 a 1989. Utilizaram-se os modelos: Von Bertalanffy, Brody, Gompertz e Logístico. Os parâmetros foram estimados usando o procedimento NLIN e os critérios utilizados para verificar o ajuste dos modelos foram: desvio padrão assintótico; coeficiente de determinação; desvio médio absoluto dos resíduos e o índice assintótico. Os modelos Von Bertalanffy e Brody superestimaram o peso assintótico (A) para os machos em 15,9 e 171,3kg, respectivamente, e os modelos Gompertz e Logístico, subestimaram em 4,5 e 13,4kg, respectivamente. Para as fêmeas, o modelo Logístico subestimou o peso assintótico (-2,09kg) e os modelos Gompertz, Von Bertalanffy e Brody superestimaram esse parâmetro em: 8,04; 17,7 e 280,33kg, respectivamente. O maior desvio médio absoluto foi estimado pelo modelo Brody para ambos os sexos, caracterizando o melhor índice. Considerando os critérios, recomenda-se o modelo Gompertz e o modelo Logístico para ajustar a curva de crescimento de fêmeas e machos da raça Murrah.

Alta similaridade cariotípica na família Emberezidae (Aves: Passeriformes) / High cariotipy similarity at the Emberezidae family (Aves: Passeriformes)

No intuito de contribuir para o conhecimento da citogenética na família Emberizidae, foram amostradas e analisadas oito espécies, empregando a técnica de cultura direta de medula óssea; na região rural pertencente ao município de Porto Nacional-TO. Seis delas, estão sendo descritas pela primeira vez: Dacnis cayana (2n=76), Tangara cayana (2n=78), Charitospiza eucosma (2n=78), Tachyphonus rufus (2n=80), Sporophila leucoptera (2n=80), e Porphyrospiza caerulescens (2n=82). Novos estudos de caracterização cromossômica foram realizados em Ramphocelus carbo (2n=78), e em Ammodramus humeralis (2n=80). Verificaram-se marcações de banda C positiva nas regiões centroméricas nos macrocromossomos, em grande parte dos microcromossomos e no braço curto do cromossomo sexual Z de T. cayana e R. carbo. As regiões organizadoras do nucléolo (NORs) foram identificadas em um par de microcromossomos; em um pequeno macrocromossomo em P. caerulescens e outro par de microcromossomos em T. cayana. Há similaridade cariotípica entre as espécies analisadas da família Emberizidae, visto que os primeiros pares de macrocromossomos apresentaram dominância de cromossomos acrocêntrico entre os quatro primeiros pares e telocêntricos entre os demais macrocromossomos, com exceção de T. rufus que apresentou uma maior predominância de cromossomos telocêntricos entre os seus primeiros pares.

This study is presented with the intention to support and contribute towards the knowledge of cytogenetic and its Emberizidae family. The 8 species have been seen in samples taken from the local rural region of Porto National-TO and cytogenetic analysis using the technique of direct culture of bone marrow. Six of the species are described here firstly the Dacnis cayana (2n=76), Tangara cayana (2n=78), Charitospiza eucosma (2n=78), Tachyphonus rufus (2n=80), Sporophila leucoptera (2n=80), and Porphyrospiza caerulescens (2n=82). New studies have characterize chromosomes were realizations in Ramphocelus carbo (2n=78), and in Ammodramus humeralis (2n=80) In R. carbo and A. humeralis, the diploid number is equal the 78 and 80 respective. The C banding shows positive marks in the centrometric region from the macro chromosome and in the short arm of the sexual chromosome Z of T. cayana e R. carbo. In P. caerulescens the nucleolus organizer regions (Nor’s) were located in a pair of micro chromosomes and in a short macro chromosome and in the pairs of micro chromosomes in T. cayana. It has conspicuous similarity which enters the analyzed species of the Emberizidae family, since the first pairs of macro chromosomes had presented predominance of chromosomes acrocentric between the first four pairs and telocentrics between the too much macro chromosomes, with exception of T. rufus that it presented a bigger predominance of telocentric chromosomes between its first pairs.

Genetic trends in the expected progeny difference of the asymptotic weight of Nelore females

There are few studies on weight covering the full life cycle of Zebu cattle, and there is no entire growth description or mean growth pattern for animals belonging to this breed. In order to provide such data, 1,158 Nelore females born between 1985 and 1995 were weighed 14,563 times from birth to full growth maturity, in ten herds spread over seven Brazilian states. The Von Bertalanffy, Brody, logistic and Gompertz non-linear models were used to obtain the asymptotic weights (A) and the maturation rates (K). The (co)variance and breeding value components for A and K were obtained by using the multiple trait derivative free restricted maximum likelihood method under the animal model. Genetic trends were calculated in function of the mean expected progeny differences (EPD) for the trait (A or K) divided by the number of animals according to their year of birth. The genetic trends of the expected progeny difference with reference to the date of birth of the cows were, on average, -6.5g y-1 for A and 2.0g y-1 for K, close to zero as confirmed by the low (0.0023 to 0.003) coefficient of regression values. The curve parameters are recommended as a selection criterion to reach precocity and avoid adult weight increase in the female herd.

Analysis of restriction fragment length polymorphism in the kappa-casein gene related to weight expected progeny difference in Nellore cattle

Restriction fragment length polymorphism (RFLP) has been detected at the bovine kappa-casein locus. The polymorphism has been analyzed for its effects in cattle production, mostly for milk traits and even for maternal effect on pre-weaning weights. We used polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) to genotype 408 Nellore animals for the non-silent mutation (Thr/Ile136 and Asp/Ala148) that characterizes the A and B variants of the polymorphism and compared expected progeny difference (EPD) for a maternal effect on 120 and 210 days weights and direct EPD for 120, 210, 450 and 550 day weight between AA and AB animals. The EPD values were obtained from the University of São Paulo (Brazil) Nellore Cattle Breeding Program, which evaluated 266,272 animals in 2001. Analysis of Variance was used to compare weight expected progeny differences (EPDs) between animals genotyped as AA and AB. The A allele frequency was 0.911. Although the AA animals had higher weight EPDs than AB animals the differences were not statistically significant (p > 0.05).

Parâmetros genéticos para perímetro escrotal en la Raza Nelore / Genetics Parameters to scrotal circumference in Nellore Cattle / Parâmetros genéticos para perímetro escrotal na Raça Nelore

El perímetro escrotal (PE) es una característica útil cuando se desea seleccionar reproductores, considerando que tiene alta correlación entre la edad a la pubertad, concentración de espermatozoides y fertilidad, además de ser una característica de fácil obtención. En el presente trabajo se estimaron parámetros genéticos para PE a los 365, 450 y 550 días de edad. La estimación se realizó mediante Modelo Animal, utilizando el software MTDFREML, considerando modelos que incluyeron como efectos fijos los grupos de contemporáneos (constituidos por rodeo, época de nacimiento, año, sexo y régimen alimentario) y la clase de edad de la vaca al parto (<36, 36-47, 48-59, 60-71, 72-119 y >120 meses), y como aleatorios los efectos genéticos directo, de ambiente permanente de la vaca y el error residual. Los valores de heredabilidad que se hallaron son de 0,47, 0,49 y 0,44, para PE365, PE450 y PE550 respectivamente. Las correlaciones entre los perímetros fueron altas y positivas, siendo de 0,85 para PE365/ PE450, 0,72 en PE365/ PE550 y 0,90 para PE450/ PE550. El efecto de ambiente permanente fue del 5 por cento, por lo que su inclusión en los modelos de análisis se podría obviar.