Função de densidade de probabilidade do número de embriões produzidos por doadoras da raça Nelore

Several models have been developed to evaluate reproductive status of cows through concentration of progesterone in milk, the effect of sex selection in the commercial production of herds and bioeconomic performance of the multiple ovulation and embryo transfer system in select herds. However, models describing the production of embryos in superovulated females have yet to be developed. A probability density function of the number of embryos collected by donors of the Nelore breed was determined. Records of 61,928 embryo collections from 26,767 donors from 1991 to 2005 were analyzed. Data were provided by the Brazilian Association of Creators of Zebu and Controlmax Consultoria e Sistemas Ltda. The probability density function of the number of viable embryos was modeled using exponential and gamma distributions. Parameter fitting was carried out for maximum likelihood using a non-linear gradient method. Both distributions presented similar level of precision: root mean square error (RMSE) = 0.0072 and 0.0071 for the exponential and gamma distributions, respectively; both distributions are thus deemed suitable for representing the probability density function of embryo production by Nelore females.Diversos modelos têm sido desenvolvidos para avaliar o estado reprodutivo de vacas por meio da concentração de progesterona no leite, o efeito da seleção do sexo na produção comercial de rebanhos e o desempenho bioeconômico da ovulação múltipla e transferência de embriões em rebanhos selecionados. No entanto, modelos que descrevem a produção de embriões em fêmeas superovulados ainda têm de ser desenvolvidos. Uma função de densidade probabilidade para o número de embriões viáveis recuperados de doadoras da raça Nelore foi determinada. Dados de 61.928 coletas de 26.767 doadoras entre 1991 e 2005 foram analisados. Os resultados foram fornecidos pela Associação Brasileira de Criadores de Zebu (ABCZ) e pela empresa Controlmax Consultoria e Sistemas Ltda.. A densidade probabilidade do número de embriões viáveis foi modelada utilizando as funções exponencial e gama. A determinação dos parâmetros foi executada utilizando o critério de máxima verossimilhança em um método de gradiente não linear. Ambas distribuições permitiram similar nível de precisão: raiz do erro quadrático médio (RMSE) = 0.0072 e 0.0071 para a distribuição exponencial e gama, respectivamente. Tanto a distribuição exponencial quanto a gama foram adequadas para representar a função de densidade probabilidade da produção de embriões para doadoras da raça Nelore

Otimização econômica do número de receptoras em programas de transferência de embriões em bovinos

Purchase and maintenance of recipient females account for a large proportion of the costs and determine the number of calves that can be produced in an embryo transfer program. However, the large variability of embryo production by the donors and the need to purchase and synchronize the recipients before knowing the number of embryos collected make it difficult for the decision maker to identify the ideal number of recipient females to allocate. An ex-ante evaluation to determine the optimal number of recipient females was carried out through a sensitivity analysis for the ratio between the number of recipients and donors in a simulation model. The variability for the number of embryos collected was accounted for by applying the Monte Carlo simulation technique, assuming normal distribution and known values for mean and variance. The simulation considered monthly intervals between collections, during a 24 months program. The effect of embryo freezing on the number of pregnancies was considered by introducing a stock of frozen embryos into the mathematical model. Optimal recipient/donor ratio and the cost per pregnancy were compared for three recipient synchronization protocols (prostaglandin, progesterone - P4 and Ovsynch), based on the expected performance for synchronization, conception and transfer/treated rates for each protocol. Stochastic simulation associated with sensitivity analysis was effective in identifying the optimal donor to recipient ratio. Freezing embryos is effective to reduce the operational costs per pregnancy. The estimated optimal recipient/donor ratio was 20 for prostaglandin and 16.7 for the other protocols. The P4 protocol, although the most expensive, resulted in the lowest pregnancy cost estimation followed by prostaglandin and Ovsynch.A aquisição e manutenção de receptoras representam grande proporção dos custos e determinam o número de produtos gerados em um programa de transferência de embriões. Entretanto, a grande variabilidade na produção de embriões e a necessidade de adquirir e sincronizar receptoras antes de conhecer o número de embriões na coleta geram dificuldades na identificação do número ideal de receptoras pelo tomador de decisão. Nesse contexto, uma avaliação ex-ante para determinação do número ótimo de receptoras foi realizada por meio de análise de sensibilidade para a razão entre o número de receptoras e de doadoras em um modelo de simulação. Considerou-se a variabilidade no número de embriões coletados aplicando-se a técnica de simulação de Monte Carlo, assumindo-se distribuição normal com média e variância do número de embriões viáveis conhecidos. Consideraram-se coletas e transferências de embriões em intervalos mensais durante um período de 24 meses. O efeito do congelamento de embriões no número de prenhezes foi representado modelando-se a dinâmica de um estoque de embriões congelados. Foram comparados a razão ótima entre receptoras e doadoras e o custo por prenhez de três protocolos de sincronização de receptoras (prostaglandina, Progesterona P4 e Ovsynch) com base em suas respectivas taxas de sincronização, aptidão e prenhez. A simulação estocástica associada com análise de sensibilidade foi efetiva em identificar a razão receptora / doadora ideal. O congelamento de embriões foi efetivo para reduzir o custo por prenhez. A razão ótima de receptoras por doadora foi afetada pelo protocolo de sincronização, sendo de 20 para a prostaglandina e de 16,7 para os demais protocolos. Apesar do maior custo, o protocolo P4 resultou na menor estimativa de custo por prenhez seguido pelo protocolo utilizando prostaglandina e pelo protocolo Ovsynch

Correlated Response on Growth Traits and Their Variabilities to Selection for Ovulation Rate in Rabbits Using Genetic Trends and a Cryopreserved Control Population

[EN] Simple Summary A successful response was obtained after selection for ovulation rate during 10 generations in rabbits. However, no correlated response in litter size was observed due to an increase in prenatal mortality. This increase could be due to the reduction in fetus weights and/or an increase in variable asynchrony among fetus weights. Therefore, the consequences of the selection procedure on weight at 28 and 63 days old (weaning and commercial time, respectively) and its variability are unknown. Using genetic trends and a cryopreserved control population for estimating correlated responses to selection, no relevant response on weight at 28 and 63 days old was observed. Similar results have been obtained for the variability of growth traits. The aim of this work was to estimate correlated responses in growth traits and their variabilities in an experiment of selection for ovulation rate during 10 generations in rabbits. Individual weight at 28 days old (IW28, kg) and at 63 days old (IW63, kg) was analyzed, as well as individual growth rate (IGR = IW63 - IW28, kg). The variability of each growth trait was calculated as the absolute value of the difference between the individual value and the mean value of their litter. Data were analyzed using Bayesian methodology. The estimated heritabilities of IW28, IW63 and IGR were low, whereas negligible heritabilities were obtained for growth variability traits. The common litter effect was high for all growth traits, around 30% of the phenotypic variance, whereas low maternal effect for all growth traits was obtained. Low genetic correlations between ovulation rate and growth traits were found, and also between ovulation rate and the variability of growth traits. Therefore, genetic trends methods did not show correlated responses in growth traits. A similar result was also obtained using a cryopreserved control population.This research was funded by Comision Interministerial de Ciencia y Tecnologia, grant number PID2020-115558GB-C21, and by Generalitat Valenciana research program (Prometeo 2009/125). Celia Quirino was supported by a fellowship of the CoordenacAo de Aperfeicoamento de Pessoal de Nivel Superior-Brasil (CAPES)-Finance Code 001.Peiró Barber, RM.; Quirino, C.; Blasco Mateu, A.; Santacreu, M. (2021). Correlated Response on Growth Traits and Their Variabilities to Selection for Ovulation Rate in Rabbits Using Genetic Trends and a Cryopreserved Control Population. Animals. 11(9):1-13. https://doi.org/10.3390/ani11092591S11311

Assessment of sexual behavior of young rams of Santa Inês breed, with and without prior experience with females

The objective of the present work was to determine if prior sexual experience with females in oestrus influences the frequency of events related to sexual behavior and if it is possible to reduce duration of the test period from 10 to 5 min. Nineteen lambs born in 2007 in Espírito Santo State, Brazil, were separated by month of birth into two groups. Those of each group were subjected to a first libido test at 7 mo of age when they had no previous exposure to females since weaning (EXP1). The second test was realized at 11 mo, when the males already had prior experience with females in oestrus (EXP2). Comportments associated with the detection of heat were frequent in both tests, while those associated with courting were more frequent in EXP2. During the first 5 min of observation the behaviors of chasing, smelling, and licking were significantly more frequent than subsequently, while frequency of other characteristics didn’t differ between times of assessment. Body weight and age influenced sexual comportment, older and heavier males tending to mount the female and ejaculate more times. It can be concluded that young rams with prior experience exhibit greater stimulus to complete copulation and that 5 min can be time enough to evaluate their libido

Effect of nursing behaviour, sex of the calf, and parity order on milk production of buffaloes

Background: the allonursing effect on daily milk production (DMP) and total milk production (TMP) has been little explored. Objective: to evaluate the effect of nursing behaviour, sex of the calf and parity order (PO) on DMP and TMP of buffalo cows. Methods: thirty-five buffalo cows and their calves were evaluated. Observations were performed monthly (three consecutive days) from May to November. The nursing behavior was characterized as: 1) isolated filial nursing (IFN); 2) collective filial nursing (CFN), and 3) non-filial nursing (NFN). Cows were grouped into four categories to study the effects of nursing behavior on DMP and TMP: 1) non-permissive (NP); 2) filial permissive (FP); 3) filial and collective filial permissive (FCFP); and 4) filial, collective filial and non-filial permissive (FCFNFP). DMP was recorded three days per month and TMP was calculated as DMP*270 days of lactation. Results: sex of the calf and second and third PO had an effect on nursing behavior (p<0.05). DMP and TMP were significantly affected by calf sex and nursing behaviour (p<0.05). PO had no effect on DMP and TMP. Conclusion: our results suggest that nursing behaviour is associated with milk production in buffalo cows. Buffalo cows that accept all types of nursing behaviour had the highest DMP and TMP. Sex of the calf influenced nursing behaviour, DMP, and TMP, so that buffalo cows with male calves displayed more frequent allonursing behaviour and yielded more milk

Avaliação genética por técnicas de modelo animal da duração da primeira lactação e produção média diária de leite da raça Caracu.

El objetivo de este estudio fue estimar los efectos genéticos y ambientales sobre la duración de la primera lactancia (DL) y la producción diaria de leche (PDL) de las vacas Caracu Criollo del hato de la Finca Recreio en Poços de Caldas, Estado de Minas Gerais. Los datos de 1 323 lactancias de vacas que parieron entre 1983 y 1990 se analizaron mediante métodos de mínimos cuadrados para obtener datos con números de subclase desiguales. Las medias de mínimos cuadrados y los errores estándar fueron 289,7 ± 7 días para DL y 4,95 ± 0,12 kg para PDL. Los efectos fijos de la temporada y el año del parto fueron significativos (P &lt;0.01) para ambos rasgos. Las estimaciones de componentes de varianza y heredabilidades, obtenidas por el algoritmo Derivative Free Maximum Likelihood (DFREML), fueron: 0.24 ± 0.08 para DL y 0.57 ± 0.09 para PDL.The objective of this study was to estimate genetic and environmental effects on first lactation length (DL) and daily milk production (PDL) of Caracu Criollo cows of the Recreio Farm herd in Poços de Caldas, State of Minas Gerais. Data from 1 323 lactations of cows that calved from 1983 to 1990, were analysed by least squares methods for data with unequal subclass numbers. Least squares means and standard errors were 289.7 ± 7 days for DL and 4.95 ± 0.12 kg for PDL. The fixed effects of season and year of parturition were significant (P&lt;0.01) for both traits. Estimates of variance components and heritabilities, obtained by the algorhythm Derivative Free Maximum Likelihood (DFREML), were: 0.24 ± 0.08 for DL and 0.57 ± 0.09 for PDL.O objetivo deste estudo foi estimar os efeitos genéticos e ambientais sobre a duração da primeira lactação (DL) e a produção diária de leite (PDL) de vacas Caracu Crioulo do rebanho da Fazenda Recreio em Poços de Caldas, Estado de Minas Gerais. Dados de 1.323 lactações de vacas que pariram de 1983 a 1990 foram analisados por métodos de quadrados mínimos para dados com números de subclasse desiguais. As médias dos mínimos quadrados e os erros padrão foram 289,7 ± 7 dias para DL e 4,95 ± 0,12 kg para PDL. Os efeitos fixos de estação e ano de parto foram significativos (P &lt;0,01) para ambas as características. As estimativas dos componentes de variância e herdabilidades, obtidas pelo algoritmo Derivative Free Maximum Likelihood (DFREML), foram: 0,24 ± 0,08 para DL e 0,57 ± 0,09 para PDL

Process of Introduction of Australian Braford Cattle to South America: Configuration of Population Structure and Genetic Diversity Evolution

This study analyzes the evolution of the population structure and genetic diversity of Braford cattle in South America from 1949 to 2019 to suggest effective strategies for breeding in the future. The percentage of bulls historically increased. The average generational interval decreased to 11.78 years for the current population. Average inbreeding (F) and coancestry (C) are low and show a historically increasing trend (0.001% to 0.002%, respectively). The degree of nonrandom mating (α) increased from −0.0001 to 0.0001 denoting a change in the trend to mate similar individuals. The average relatedness coefficient (ΔR) increased in the current period from 0.002% to 0.004%. A single ancestor explained 4.55% to 7.22% of the population’s gene pool. While the effective population size based on the individual inbreeding rate (NeFi) was 462.963, when based on the individual coancestry rate (NeCi), it was 420.168. Genetic diversity loss is small and mainly ascribed to bottlenecks (0.12%) and to unequal contributions of the founders (0.02%). Even if adequate levels of diversity can be found, practices that consider the overuse of individual bulls (conditioned by nature or not), could lead to a long-term reduction in diversity. The present results permit tailoring genetic management strategies that are perfectly adapted to the needs that the population demands internationally

MODELAGEM BIOECONÔMICA DA TRANSFERÊNCIA DE EMBRIÕES EM BOVINOS

O objetivo deste trabalho foi desenvolver um modelo matemático orientado a eventos de simulação, para auxiliar tomadas de decisão relativas à transferência de embriões em bovinos, considerando-se as dinâmicas de dois componentes da transferência de embriões: receptoras e embriões. Na simulação, não se avaliaram respostas individuais de doadoras a coletas consecutivas e eventos correspondentes na transferência de embriões. Simulou-se o mesmo protocolo para superovulação a todas as doadoras. Receptoras foram sincronizadas simulando-se o uso de prostaglandina. O número de embriões viáveis produzido por doadora e sua variabilidade tiveram como base um processo aleatório de simulação de Monte Carlo, que pressupôs uma distribuição exponencial negativa de densidade de probabilidade. Custos e receitas foram inseridos no modelo por meio de um cenário-base para calcular indicadores econômicos de rentabilidade. A análise sugeriu a impraticabilidade da atividade, se realizada diante do cenário proposto (VPL – R$: 57.596,69). A partir do cenário proposto, o custo médio estimado foi de R$ 1.178,19, e de R$ 980,03, para se obter uma prenhez a partir de uma situação otimizada, sugerida pelo modelo (5/100; 5/190). PALAVRAS-CHAVES: Otimização, receptoras, simulação, transferência de embriões, viabilidade econômica

Deterministic and stochastic models to embryo transfer programs in bovine

The aim of this study was to evaluate deterministic and stochastic models to get decision support to embryo transfer programs in bovine. The number of recipient that minimize cost per pregnancy was carried out through sensibility analysis in a mathematical model. The number of embryos collected was accounted for by a Monte-Carlo simulation. The embryos variability and economic costs related to recipient maintenance at the system were evaluated. It was compared results from stochastical models to deterministic equations. Results showed that simulation in embryo transfer is particular important when exists high variability in number of embryos collected, few number of donors and low recipient maintenance costs

Avaliação de medidas corporais e testiculares em ovinos Dorper em diferentes idades

The aim of the study was to evaluate body and testicular measurements of 18 pure Dorper males (PD) at different ages in Rio de Janeiro, Brazil. The height at the withers, rump height, body length, thoracic perimeter, body condition score (BCS), scrotal circumference (SC), length and width of the testes were recorded at 7, 12, 18 e 32 months of age. The data were compared at different ages using an analysis of variance and the correlations between the measurements were calculated. The body measurements of PD were influenced by the age (p &lt; 0,05). The SC measurement showed a high correlation with the thoracic perimeter (0.85), and with the BCS (0.82). Morphometric and testicular measurements were influenced by the age of the animals. Scrotal circumference can be used as a selection criterion for PD, since testicular and body measurements showed positive correlations.El objetivo del estudio fue evaluar las medidas corporales y testiculares de 18 machos Dorper puros de origen (PO) de diferentes edades en Río de Janeiro, Brasil. La altura a la cruz, altura a la grupa, longitud del cuerpo, perímetro torácico, índice de condición corporal (ICC), circunferencia escrotal (CE), longitud y ancho de los testículos se registraron a los 7, 12, 18 y 32 meses de edad. Los datos fueron comparados a diferentes edades mediante un análisis de varianza y se calcularon las correlaciones entre las medidas. Las medidas corporales de los Dorper (PO) fueron influenciadas por la edad (p &lt; 0,05). La medida CE mostró una alta correlación con el perímetro torácico (0,85) y con el ICC (0,82). Las medidas morfométricas y testiculares estuvieron influenciadas por la edad de los animales. La circunferencia escrotal se puede utilizar como criterio de selección para Dorper (PO) ya que las medidas testiculares y corporales presentaron correlaciones positivas.O objetivo do estudo foi avaliar as medidas corporais e testiculares de 18 machos Dorper puros de origem (PO) em diferentes idades no Rio de Janeiro, Brasil. A altura na cernelha, altura da garupa, comprimento corporal, perímetro torácico, escore de condição corporal (ECC), circunferência escrotal (EC), comprimento e largura dos testículos foram registrados aos 7, 12, 18 e 32 meses de idade. Os dados foram comparados em diferentes idades por meio de uma análise de variância e as correlações entre as medidas foram calculadas. As medidas corporais dos Dorper (PO) foram influenciadas pela idade (p &lt; 0,05). A medida do EC apresentou alta correlação com o perímetro torácico (0,85) e com o ECC (0,82). As medidas morfométricas e testiculares foram influenciadas pela idade dos animais. A circunferência escrotal pode ser utilizada como critério de seleção para Dorper (PO), uma vez que as medidas testiculares e corporais apresentaram correlações positivas