Prevalence of natural infection by Trypanosoma evansi in Crioula LAGEANA cattle.

Cattle trypanosomiasis negatively impacts animal husbandry due to high morbidity, productivity losses, and mortality rates. Knowledge regarding Trypanosoma evansi infections in locally adapted breeds remains limited. Some cattle breeds exhibit trypanotolerance, requiring the determination of prevalence, as well as related tolerance and resistance characteristics, for disease control programs. This study aimed to determine T. evansi prevalence in Crioula Lageana cattle and associate clinical, hematological, and biochemical aspects with the infection to further research on tolerance in this population. Blood samples from 310 Crioula Lageana cattle were tested using Polymerase Chain Reaction (PCR) and Indirect Immunofluorescence Reaction (IIFR). T. evansi prevalence was 8% (24/310) using PCR and 4% (11/310) using IIFR. Positive animals showed increased ruminal movements, elevated eosinophil counts, and reduced monocyte numbers, but both latter within the reference range for the species. Albumin concentrations were low in positive cases and remained below the reference range limit for both groups. However, triglycerides exceeded the physiological range for the species in both positive and negative groups. Increased gamma-glutamyltransferase (GGT) activity was observed in positive animals. In conclusion, Crioula Lageana cattle exhibited enzootic instability with a low T. evansi infection prevalence when assessed using PCR and IIFR techniques. Furthermore, the animals did not display clinical, hematological, or biochemical alterations attributable to the presence of hemoparasites.

Prevalence and Risk Factors Associated With Natural Infection by Trypanosoma evansi in Campeiro Horses.

Campeiro horse is a breed locally adapted to the Santa Catarina plateau region and its main characteristic is the gait, it is known as "Marchador das Araucárias." It is a breed considered in danger of extinction, being fundamental the search for the preservation of this important genetic resource. Surra, caused by the protozoan Trypanosoma evansi, is among the diseases that affect horses. However, there are no data on the prevalence of infection in Campeiro horses. This study aimed to determine the prevalence of T. evansi in Campeiro horses, correlate hematology and serum biochemistry, and identify possible risk factors. Blood samples were collected by venipuncture of 214 Campeiro horses, 50 males and 164 females, aged between 3 months and 27 years, from 16 properties located in the States of Santa Catarina, Rio Grande do Sul, and Paraná. An epidemiological questionnaire was carried out with the owners to analyze the associated risk factors. The blood samples were submitted to polymerase chain reaction, immunofluorescence antibody test, complete blood count, and serum biochemistry. The prevalence was 14% of positive animals by polymerase chain reaction and 59% by immunofluorescence antibody test . There was an increase in hematocrit, and in the number of basophils, a decrease in plasmatic fibrinogen, and in the enzymatic activity of alanine aminotransferase, aspartate aminotransferase, and urea, and an increase in creatine phosphokinase and creatinine in positive animals, which is possibly unrelated to the infection. The data obtained through the epidemiological questionnaires showed no difference. Therefore, T. evansi is present in the South of Brazil, with a high prevalence in Campeiro horses.

Coat color and morphological hair traits influence on the mechanisms related to the heat tolerance in hair sheep.

The principal focus of this study was to describe how the coat characteristics could affect the heat exchanges in animals managed in a hot environment. The Morada Nova ewes were monitored once a month, during 10 consecutive months, in three commercial flocks. Initially, an analysis was performed to measure the differences regarding the coat color in the thermoregulation mechanisms. The animals were grouped into 4 different groups according to coat tonality, as follows: dark red animals (group 1, N = 23), intermediate red color (group 2, N = 27), light red animals (group 3, N = 30), and white-coated animals (group 4, N = 30). The data were collected from 1100 to 1400 h, after the animals were exposed to 30 min of direct sunlight. The cluster analysis was performed considering the hair structural characteristics such as coat thickness (CT, cm), hair length (HL, mm), hair diameter (HD, m), and number of hairs (NH, hairs per unit area), after that these clusters were compared in relation to thermoregulatory mechanisms that include rectal temperature (RT, °C), respiratory rate (RR, breaths min-1), cutaneous evaporation (CE, °C), and respiratory evaporation (RE, W m-2). The groups were characterized and compared using mean and standard deviation, and the differences between the clusters were compared using the Tukey test with a 5% probability of error. In relation to coat color, no differences were found in groups 1, 2, and 3 regarding the activation of the thermoregulation mechanisms. The most different was observed in the totally white coat that presented different thermoregulatory responses as the highest sweating rate. White-coated animals showed a non-pigmented epidermis, and the hair structure is responsible to promote skin protection as necessary, such as a dense coat (1242.7 hair cm-2), long hair (14.2 mm), and thicker coat (7.38 mm). In red-coated animals, the hair structure favored heat loss to the environment, such as short hairs, less thick coat, and less hairs per square centimeter. All evaluated animals showed the rectal temperature within the reference limits for the ovine species, regardless of the coat color. In the analysis of clusters related to the physical structure of hair, it was possible to observe that the animals with thick hair, short hair, and less dense coat tended to have a higher capacity to eliminate heat through their respiratory rate and showed less intense heat loss by cutaneous evaporation. We verified that coat color presents a direct influence on the hair structure and the activation of mechanisms related to thermoregulation.

Population structure of Brazilian Crioula Lageana cattle ( Bos taurus ) breed / Estructura poblacional de la raza bovina brasileña Crioula Lageana (Bos taurus) / Estrutura populacional da raça brasileira bovina Crioula Lagenana (Bos taurus)

Abstract Background: The lack of information on population structure is one of the main obstacles to develop breeding and conservation programs for animal genetic resources. Objective: To characterize the population structure of Crioula Lageana cattle breed (Bos taurus) in order to assess its genetic diversity. Methods: Database with information of 1,638 Crioula Lageana animals, collected during 38 years, was analysed using the ENDOG v.4.4 program. Results: Effective population size ranged from 72.53 in complete generations to 143.90 in maximum generations. Inbreeding and Average Relatedness coefficients were 0.34 and 0.91%, respectively. The effective number of founders and ancestors were 29 and 28 animals, respectively, and only ten ancestors were responsible for 50% of the genetic variability of the whole population. The average generation interval was 5.84 years in the paternal line and 7.70 in the maternal one. Wright´s F statistics indicated low genetic distances between subsets in relation to the total population (Fst = 0.0015), between individuals with respect to their subpopulation (Fis = -0.0027), and between individuals in relation to the total population (Fit = -0.0012). Conclusion: Analysis of the population indicated that, despite the small number of animals with known parentage and considerable loss of genetic variability by the constant use of a few sires, and same value of number of founders and ancestors, the population showed good genetic management, low inbreeding, low genetic differentiation among subpopulations, and probably adequate effective population size for breed preservation.

Resumen Antecedentes: La falta de información sobre estructura poblacional es una de las principales barreras para el desarrollo de programas de mejoramiento genético y conservación de los recursos zoogenéticos. Objetivo: Caracterizar la estructura poblacional de la raza bovina Crioula Lageana (Bos taurus) para evaluar su diversidad genética. Métodos: Una base de datos con información de 1.638 animales Crioula Lageana (Bos taurus), recogidos durante 38 años, fue analizada utilizando el programa ENDOG v.4.4. Resultados: El tamaño efectivo de la población varió de 72,53 en las generaciones completas a 143,90 en las generaciones máximas. La endogamia y la relación media de los coeficientes fue 0,34 y 0,91%, respectivamente. El número efectivo de fundadores y antepasados fue de 29 y 28 animales respectivamente, y sólo diez antepasados fueron responsables del 50% de la variabilidad genética de la población. El intervalo promedio de generación fue de 5,84 años en la línea paterna y de 7,70 en la línea materna. El índice estadístico de Wright's F indica una baja distancia genética entre los subconjuntos en relación con la población total (Fst = 0,0015), entre los individuos con respecto a su subpoblación (Fis = -0,0027), y entre los individuos en relación con la población total (Fit = -0,0012). Conclusión: El análisis de la población indica que a pesar del pequeño número de animales con origen conocido y la considerable pérdida de variabilidad genética por el uso constante de pocos toros y el mismo valor del número de fundadores y antepasados, la población mostró un buen manejo genético, baja endogamia, baja diferenciación genética entre las subpoblaciones y probablemente un tamaño efectivo adecuado de la población.

Resumo Antecedentes: A falta de informações sobre a estrutura da população está entre os principais obstáculos ao desenvolvimento de programas de melhoramento e conservação de recursos genéticos animais. Objetivo: Caracterizar a estrutura populacional da raça bovina Crioula Lageana (Bos taurus) para acessar a diversidade genética da raça. Métodos: Banco de dados com informação de 1.638 animais Crioula Lageana, recolhidos durante 38 anos, foi analisado utilizando EndoG v.4.4. Resultados: O tamanho efetivo populacional variou de 72,53 nas gerações completas para 143,90 nas gerações máximas. Coeficientes de Endogamia e Relação foram 0,34 e 0,91%, respectivamente. O número efetivo de fundadores e ancestrais foram 29 e 28 animais, respectivamente, sendo que apenas dez ancestrais foram responsáveis por 50% da variabilidade genética de toda a população. O intervalo de gerações foi de 5,84 anos para linha paterna e 7,70 para linha materna. As estatísticas F de Wright indicaram uma pequena distância genética das subpopulacoes entre os subgrupos em relação à população total (FST = 0,0015), entre os indivíduos em relação à sua subpopulação (FIS = -0,0027) e entre indivíduos em relação à população total (Fit = -0,0012). Isto indica uma baixa diferenciação genética na população estudada. Conclusão: A análise populacional indicou que, apesar do número pequeno de animais com ascendência conhecida e considerável perda de variabilidade genética pelo uso constante de alguns touros e mesmo valor do número de fundadores e antepassados, a população mostrou boa gestão genética, endogamia baixa, baixa diferenciação genética entre subpopulações e provavelmente adequado tamanho efetivo da população para a preservação da raça.

Postpartum hormone and energy profiles and their influence on the resumption of ovarian cyclicity in Curraleiro Pé-Duro cows.

The objective of this study was to evaluate hormone and energy profiles in the postpartum period and to correlate these profiles with the resumption of ovarian cyclicity, as well as characterizing the postpartum short estrous cycle of Curraleiro Pé-Duro cows. Twelve Curraleiro Pé-Duro cows were examined via rectal palpation and ultrasound at 10 days postpartum, and subsequently examined daily to evaluate the resumption of ovarian cyclicity as well as every five days in order to evaluate uterine involution. Upon analysis of the data, it was possible to observe the formation of two distinct groups, one of which was comprised of those animals which returned to cyclicity within 60 days postpartum and another comprised of those animals which returned to cyclicity more than 105 days postpartum. Therefore, animals were divided into two groups; precocious, designated Ov Group, and delayed, designated NOv Group, wherein the cut-off time for all tests was 60 days postpartum. Statistically significant differences (P < 0.01) between the groups occurred only regarding the day of 1st ovulation, which in the Ov Group averaged 51.4 ± 9.3 days and in the NOv Group averaged 138.3 ± 19.8 days postpartum. The other postpartum short estrous cycle variables assessed did not show statistically significant differences (P > 0.05) between the groups. NEFA, BHBA and thyroxine concentration levels did not differ (P > 0.05) between the groups in any of the statistical analyses. However, in the analysis comparing growth curves, triglycerides levels were higher for the Ov Group (P = 0.04) and cholesterol levels were higher for the NOv Group (P = 0.02). In this experiment, a small influence of a negative energy balance between the groups was observed, suggesting that these animals can present significant genetic variability due to natural selection, as evidenced by the formation of groups of animals with precocious and delayed reproductive characteristics.

Application of microsatellite markers for breeding and genetic conservation of herds of Pantaneiro sheep

Background The aim of the present study was to assess the genetic diversity of Pantaneiro sheep, using microsatellite markers, in order to assist maintenance and management plans, enhance mating systems and reduce the inbreeding rate. A total of 127 animals were genotyped at eight microsatellite loci. They belonged to populations from the Experimental Farm of the Universidade Federal da Grande Dourados (UFGD) (Dourados/MS/Brazil) and Embrapa Pantanal (Corumbá/MS/Brazil). Results The population of Pantaneiro sheep from the UFGD exhibited a high mean number of alleles (11.13) and allelic richness (10.66). The polymorphic information content was highly informative in the locus studied, resulting in a mean value of 0.71. Observed heterozygosity was lower than expected for all molecular markers assessed. The analysis of molecular variance showed a differentiation rate of 5.2% between populations. Conclusions The results of the statistical parameters indicated that populations of Pantaneiro sheep require special attention on herd management, and it's further necessary to implement breeder exchange programs in order to preserve the genetic variability of these populations. Furthermore, the maintenance of those populations in their typical habitats is rather required to allow different responses from the herds to the interactions between genotype and environment.