How does reproduction account for dairy farm sustainability?

Sustainability - the new hype of the 21st century has brought discomfort for the government and society. Sustainable agriculture is essential to face our most concerning challenges: climate change, food security, and the environmental footprint, all of which add to consumers' opinions and choices. Improvements in reproductive indexes can enhance animal production and efficiency, guaranteeing profit and sustainability. Estrus detection, artificial insemination (AI), embryo transfer (ET), estrus synchronization (ES), and multiple ovulations are some strategies used to improve animal reproduction. This review highlights how reproductive strategies and genetic selection can contribute to sustainable ruminant production. Improved reproductive indices can reduce the number of nonproductive cows in the herd, reducing methane emissions and land use for production while preserving natural resources.(AU)

Evaluation of a new additive-dominance genomic model and implications for quantitative genetics and genomic selection

The Fisher's infinitesimal model is traditionally used in quantitative genetics and genomic selection, and it attributes most genetic variance to additive variance. Recently, the dominance maximization model was proposed and it prioritizes the dominance variance based on alternative parameterizations. In this model, the additive effects at the locus level are introduced into the model after the dominance variance is maximized. In this study, the new parameterizations of additive and dominance effects on quantitative genetics and genomic selection were evaluated and compared with the parameterizations traditionally applied using the genomic best linear unbiased prediction method. As the parametric relative magnitude of the additive and dominance effects vary with allelic frequencies of populations, we considered different minor allele frequencies to compare the relative magnitudes. We also proposed and evaluated two indices that combine the additive and dominance variances estimated by both models. The dominance maximization model, along with the two indices, offers alternatives to improve the estimates of additive and dominance variances and their respective proportions and can be successfully used in genetic evaluation.

Multilayer perceptron applied to genotypes classification in diallel studies

In the last decades, a new trend to use more refined analytical procedures, such as artificial neural networks (ANN), has emerged to be most accurate, efficient, and extensively applied for mining and data prediction in different contexts, including plant breeding. Thus, this study was developed to establish a new classification proposal for targeting genotypes in breeding programs to approach classical models, such as a complete diallel and modern prediction techniques. The study was based on the standard deviation values of an interpopulation diallel and it also verified the possibility of training a neural network with the standardized genetic parameters for a discrete scale. We used 12 intercrossed maize populations in a complete diallel scheme (66 hybrids), evaluated during the 2005/2006 crop season in three different environments in southern Brazil. The implemented MLP architecture and other associated parameters allowed the development of a generalist model of genotype classification. The MLP neural network model was efficient in predicting parental and interpopulation hybrid classifications from average genetic components from a complete diallel, regardless of the evaluation environment.(AU)

Innate immunity in chicken lines developed by EMBRAPA Suínos e Aves: antimicrobial activity of macrophages and serum

The objective of this study was to compare the antimicrobial activity of macrophages and serum in laying hen (MM, CC, and CCc) and broiler chicken lineages (TT and LL). Macrophages were evaluated for phagocytic and antimicrobial activity. Microbicidal serum activity was evaluated by the resistance test for serum and the agar test. The results showed that phagocytic activity was higher in males of the MM strain, with 13% of macrophages presenting phagocytosis, while the other lineages studied, and even female MM, presented a rate of 6% of phagocytic cells. However, antimicrobial activity in macrophages from males of CCc lineage and females of TT lineage were higher, eliminating more than 30% of the Salmonella enterica inoculum, while in the other strains, the results were similar, with inoculum reduction below 30%. In the serum resistance assay, female laying lines presented higher antibacterial activity than female broiler lines. In the trials to evaluate the microbicide activity of the serum, females of both broiler and laying lineages presented higher performance when compared with males of the same lineage. Females of laying hen lines (MM and CC) present a greater antibacterium activity than males. These results can contribute to a better understanding of the immune response in broiler chicken and laying hen lineages, to aid development of lineages of birds more resistant to pathogens.

Soybean productivity, stability, and adaptability through mixed model methodology / Produtividade, estabilidade e adaptabilidade da soja por meio de metodologia de modelo misto

The genotype × environment (G×E) interaction plays an essential role in phenotypic expression and can lead to difficulties in genetic selection. Thus, the present study aimed to estimate genetic parameters and to compare different selection strategies in the context of mixed models for soybean breeding. For this, data referring to the evaluation of 30 genotypes in 10 environments, regarding the grain yield trait, were used. The variance components were estimated through restricted maximum likelihood (REML) and genotypic values were predicted through best linear unbiased prediction (BLUP). Significant effects of genotypes and G×E interaction were detected by the likelihood ratio test (LRT). Low genotypic correlation was obtained across environments, indicating complex G×E interaction. The selective accuracy was very high, indicating high reliability. Our results showed that the most productive soybean genotypes have high adaptability and stability.(AU)

A interação genótipo × ambiente (G × E) desempenha um papel essencial na expressão fenotípica e pode provocar dificuldades na seleção genética. Assim, o presente estudo teve como objetivo estimar parâmetros genéticos e comparar diferentes estratégias de seleção no contexto de modelos mistos para melhoramento da soja. Para isso, foram utilizados dados referentes à avaliação de 30 genótipos em dez ambientes, referentes à característica produtividade de grãos. Os componentes de variância foram estimados pela máxima verossimilhança restrita (REML) e os valores genotípicos foram preditos pela melhor previsão imparcial linear (BLUP). Efeitos significativos dos genótipos e interação G × E foram detectados pelo teste da razão de verossimilhança (LRT). Correlação genotípica baixa foi obtida entre os ambientes indicando interação G × E do tipo complexa. A acurácia seletiva foi muito alta, indicando alta confiabilidade. Os resultados mostraram que os genótipos de soja mais produtivos apresentam alta adaptabilidade e estabilidade.(AU)

Recent advances in pig reproduction: 2. Higher litter size / Recentes avanços na reprodução suina: 2. Leitegadas maiores

In the past 30 years, sows have been successfully selected for increased litter size. This review discusses the consequences of this selection for the reproductive physiology of sows, including the consequences for litter characteristics at birth. It also discusses breeding and management opportunities to deal with these modern genetics.(AU)

Recent advances in pig reproduction: 2. Higher litter size / Recentes avanços na reprodução suina: 2. Leitegadas maiores

In the past 30 years, sows have been successfully selected for increased litter size. This review discusses the consequences of this selection for the reproductive physiology of sows, including the consequences for litter characteristics at birth. It also discusses breeding and management opportunities to deal with these modern genetics.

Recent advances in pig reproduction: 1. Shorter weaning-to-oestrus interval / Recentes avanços na reprodução suína: 1. Intervalos mais curtos da desmama-estro

In the past 30 years, sows have been successfully selected for a shorter weaning-to-oestrus interval and increased litter size. This review discusses the consequences of this selection for the reproductive physiology of sows, including the consequences for litter characteristics at birth. It also discusses breeding and management opportunities to deal with these modern genetics.(AU)

Association between gestation length and lactation performance, lactation curve, calf birth weight and dystocia in Holstein dairy cows in Iran

In this study, 252,798 lactations on 108,077 cows in 433 herds were used to determine the association between gestation length (GL) and lactation performance, lactation curve, calf birth weight and dystocia in Holstein dairy cows in Iran. The GL averaged 278.1 ± 5.41 d, was categorized as short (SGL; at 1 SD below the population mean), average (AGL; the population mean ± 1 SD), or long (LGL; at least 1 SD above the population mean). Factors including parity, calf gender and calving season were associated with the GL. Primiparous cows with SGL had less lactation performance than those with longer GL; however, there was no difference between those with AGL and LGL. Multiparous cows with longer GL always had more partial and 305-d lactation performance. Primiparous cows with SGL produced less milk at the beginning of lactation and at the peak than those with AGL or LGL; inverse trends were found for lactation persistency, upward and downward slopes of the lactation curve. Within multiparous, a direct relationship was found between GL and the peak yield, where cows with longer GL always produced more milk at the peak. Multiparous cows with SGL produced less milk at the beginning of lactation, reached their peaks later, had higher lactation persistency and showed a lower upward slope of lactation curve than those with AGL or LGL. There was a direct relationship between GL and calf birth weight, where cows with longer GL had calves with more weight at the birth. Within primiparous, cows with SGL had the lowest and those with LGL had the highest rate of dystocia. However, multiparous cows with AGL had a lower rate of dystocia than those with SGL or LGL. Although there was a direct relationship between GL and lactation performance, intermediate GL seems optimal when considering dystocia.(AU)

Association between gestation length and lactation performance, lactation curve, calf birth weight and dystocia in Holstein dairy cows in Iran

In this study, 252,798 lactations on 108,077 cows in 433 herds were used to determine the association between gestation length (GL) and lactation performance, lactation curve, calf birth weight and dystocia in Holstein dairy cows in Iran. The GL averaged 278.1 ± 5.41 d, was categorized as short (SGL; at 1 SD below the population mean), average (AGL; the population mean ± 1 SD), or long (LGL; at least 1 SD above the population mean). Factors including parity, calf gender and calving season were associated with the GL. Primiparous cows with SGL had less lactation performance than those with longer GL; however, there was no difference between those with AGL and LGL. Multiparous cows with longer GL always had more partial and 305-d lactation performance. Primiparous cows with SGL produced less milk at the beginning of lactation and at the peak than those with AGL or LGL; inverse trends were found for lactation persistency, upward and downward slopes of the lactation curve. Within multiparous, a direct relationship was found between GL and the peak yield, where cows with longer GL always produced more milk at the peak. Multiparous cows with SGL produced less milk at the beginning of lactation, reached their peaks later, had higher lactation persistency and showed a lower upward slope of lactation curve than those with AGL or LGL. There was a direct relationship between GL and calf birth weight, where cows with longer GL had calves with more weight at the birth. Within primiparous, cows with SGL had the lowest and those with LGL had the highest rate of dystocia. However, multiparous cows with AGL had a lower rate of dystocia than those with SGL or LGL. Although there was a direct relationship between GL and lactation performance, intermediate GL seems optimal when considering dystocia.

Breeding goals and economic values for Nellore cattle in a full-cycle production system

The objective of this study was to develop a bio-economic model for the estimation of economic values of economically important traits in a full-cycle beef cattle production system. The bioeconomic model calculated economic values by simulating the impact of changes in the profit of the system consisting of a 1% increase in each trait of the breeding objective, while the other traits were kept constant. The bio-economic model was effective in estimating the sources of revenues and expenses of the production system. The estimated economic values were, in the order of importance for the full-cycle system, R$ 3.69 for male slaughter weight, R$ 3.63 for male weaning weight, R$ 3.58 for weaning rate, R$ 3.40 for female slaughter weight, R$ 2.30 for female weaning weight, and R$ 0.13 for mature cow weight. The results showed that all traits evaluated in the full-cycle system had positive economic impact, indicating that selection would increase profitability maximizing the expected response for the traits of the breeding goal.(AU)

Breeding goals and economic values for Nellore cattle in a full-cycle production system

The objective of this study was to develop a bio-economic model for the estimation of economic values of economically important traits in a full-cycle beef cattle production system. The bioeconomic model calculated economic values by simulating the impact of changes in the profit of the system consisting of a 1% increase in each trait of the breeding objective, while the other traits were kept constant. The bio-economic model was effective in estimating the sources of revenues and expenses of the production system. The estimated economic values were, in the order of importance for the full-cycle system, R$ 3.69 for male slaughter weight, R$ 3.63 for male weaning weight, R$ 3.58 for weaning rate, R$ 3.40 for female slaughter weight, R$ 2.30 for female weaning weight, and R$ 0.13 for mature cow weight. The results showed that all traits evaluated in the full-cycle system had positive economic impact, indicating that selection would increase profitability maximizing the expected response for the traits of the breeding goal.

Recent advances in pig reproduction: 1. Shorter weaning-to-oestrus interval / Recentes avanços na reprodução suína: 1. Intervalos mais curtos da desmama-estro

In the past 30 years, sows have been successfully selected for a shorter weaning-to-oestrus interval and increased litter size. This review discusses the consequences of this selection for the reproductive physiology of sows, including the consequences for litter characteristics at birth. It also discusses breeding and management opportunities to deal with these modern genetics.

Weight gain and morphometric growth of genetically improved tambaqui (Colossoma macropomum) / Ganho de peso e crescimento morfométrico do tambaqui (Colossoma macropomum) melhorado geneticamente

Weight gain and morphometric growth of the genetically improved tambaqui (Colossoma macropomum) are evaluated. Current assay was carried out on the Fish Farm Experimental Station of the Federal University of Mato Grosso, in the municipality of Santo Antonio de Leverger - MT Brazil. Seven fish families from the breeding program and a control group (not genetically improved) were evaluated. All animals were individually identified with a transmitter-responder label (transponder). Weight gain, overall and standard length, head size, height, width and body perimeter were measured. A completely randomized design was used and comparisons among families and the control group were carried out by Dunnett test at 5% significance level. The genetically improved fish families showed a 14.8% higher weight gain when compared to that of control group. Five out of seven families showed greater weight gain when compared to control group, with the best family exhibiting a 24.8% higher rate. Four families had higher growth in all evaluated morphometric characteristics when compared to control group. Only one family did not differ in any of the evaluated characteristics with regard to the control group.

Objetivou-se avaliar o ganho de peso e o crescimento morfométrico do tambaqui (Colossoma macropomum) melhorado geneticamente. O trabalho foi realizado na Estação Experimental de Piscicultura da Universidade Federal de Mato Grosso, localizada no município de Santo Antônio de Leverger - MT, Brasil. Foram avaliadas sete famílias oriundas do programa de melhoramento genético e um grupo controle (não melhorado geneticamente). Todos os animais foram individualizados com transponder. Foram mensurados o ganho de peso, comprimento total e padrão, tamanho de cabeça, altura, largura e perímetro do corpo. Utilizou-se delineamento inteiramente casualizado e as comparações entre as famílias e o grupo controle foram realizadas pelo teste de Dunnett com 5% de significância. As famílias melhoradas geneticamente apresentaram ganho de peso 14,8% superior ao grupo controle. Cinco das sete famílias avaliadas apresentaram maior ganho de peso em relação ao grupo controle, sendo que a melhor família foi superior em 24,8%. Quatro famílias apresentaram maior crescimento em todas as características morfométricas avaliadas em relação ao controle. Apenas uma família não diferiu em nenhuma das características avaliadas em relação ao grupo controle.

Weight gain and morphometric growth of genetically improved tambaqui (Colossoma macropomum) / Ganho de peso e crescimento morfométrico do tambaqui (Colossoma macropomum) melhorado geneticamente

Weight gain and morphometric growth of the genetically improved tambaqui (Colossoma macropomum) are evaluated. Current assay was carried out on the Fish Farm Experimental Station of the Federal University of Mato Grosso, in the municipality of Santo Antonio de Leverger - MT Brazil. Seven fish families from the breeding program and a control group (not genetically improved) were evaluated. All animals were individually identified with a transmitter-responder label (transponder). Weight gain, overall and standard length, head size, height, width and body perimeter were measured. A completely randomized design was used and comparisons among families and the control group were carried out by Dunnett test at 5% significance level. The genetically improved fish families showed a 14.8% higher weight gain when compared to that of control group. Five out of seven families showed greater weight gain when compared to control group, with the best family exhibiting a 24.8% higher rate. Four families had higher growth in all evaluated morphometric characteristics when compared to control group. Only one family did not differ in any of the evaluated characteristics with regard to the control group.(AU)

Objetivou-se avaliar o ganho de peso e o crescimento morfométrico do tambaqui (Colossoma macropomum) melhorado geneticamente. O trabalho foi realizado na Estação Experimental de Piscicultura da Universidade Federal de Mato Grosso, localizada no município de Santo Antônio de Leverger - MT, Brasil. Foram avaliadas sete famílias oriundas do programa de melhoramento genético e um grupo controle (não melhorado geneticamente). Todos os animais foram individualizados com transponder. Foram mensurados o ganho de peso, comprimento total e padrão, tamanho de cabeça, altura, largura e perímetro do corpo. Utilizou-se delineamento inteiramente casualizado e as comparações entre as famílias e o grupo controle foram realizadas pelo teste de Dunnett com 5% de significância. As famílias melhoradas geneticamente apresentaram ganho de peso 14,8% superior ao grupo controle. Cinco das sete famílias avaliadas apresentaram maior ganho de peso em relação ao grupo controle, sendo que a melhor família foi superior em 24,8%. Quatro famílias apresentaram maior crescimento em todas as características morfométricas avaliadas em relação ao controle. Apenas uma família não diferiu em nenhuma das características avaliadas em relação ao grupo controle.(AU)

Weight gain and morphometric growth of genetically improved tambaqui (Colossoma macropomum) / Ganho de peso e crescimento morfométrico do tambaqui (Colossoma macropomum) melhorado geneticamente

Weight gain and morphometric growth of the genetically improved tambaqui (Colossoma macropomum) are evaluated. Current assay was carried out on the Fish Farm Experimental Station of the Federal University of Mato Grosso, in the municipality of Santo Antonio de Leverger - MT Brazil. Seven fish families from the breeding program and a control group (not genetically improved) were evaluated. All animals were individually identified with a transmitter-responder label (transponder). Weight gain, overall and standard length, head size, height, width and body perimeter were measured. A completely randomized design was used and comparisons among families and the control group were carried out by Dunnett test at 5% significance level. The genetically improved fish families showed a 14.8% higher weight gain when compared to that of control group. Five out of seven families showed greater weight gain when compared to control group, with the best family exhibiting a 24.8% higher rate. Four families had higher growth in all evaluated morphometric characteristics when compared to control group. Only one family did not differ in any of the evaluated characteristics with regard to the control group.

Objetivou-se avaliar o ganho de peso e o crescimento morfométrico do tambaqui (Colossoma macropomum) melhorado geneticamente. O trabalho foi realizado na Estação Experimental de Piscicultura da Universidade Federal de Mato Grosso, localizada no município de Santo Antônio de Leverger - MT, Brasil. Foram avaliadas sete famílias oriundas do programa de melhoramento genético e um grupo controle (não melhorado geneticamente). Todos os animais foram individualizados com transponder. Foram mensurados o ganho de peso, comprimento total e padrão, tamanho de cabeça, altura, largura e perímetro do corpo. Utilizou-se delineamento inteiramente casualizado e as comparações entre as famílias e o grupo controle foram realizadas pelo teste de Dunnett com 5% de significância. As famílias melhoradas geneticamente apresentaram ganho de peso 14,8% superior ao grupo controle. Cinco das sete famílias avaliadas apresentaram maior ganho de peso em relação ao grupo controle, sendo que a melhor família foi superior em 24,8%. Quatro famílias apresentaram maior crescimento em todas as características morfométricas avaliadas em relação ao controle. Apenas uma família não diferiu em nenhuma das características avaliadas em relação ao grupo controle.

CARACTERÍSTICAS FUNCIONAIS, PRODUTIVAS E DE TIPO EM BOVINOS DA RAÇA HOLANDESA NO BRASIL - UMA ABORDAGEM MULTIVARIADA

Scheid, Angelica Leticia. Características Funcionais, Produtivas e de Tipo em Bovinos da Raça Holandesa no Brasil - uma Abordagem Multivariada. 2019. 75 p. Dissertação (Mestrado em Ciência Animal Área: Produção Animal) Universidade do Estado de Santa Catarina. Programa de Pós-Graduação em Ciência Animal, Lages, 2019. A avaliação da relação da conformação da vaca leiteira com a sua funcionalidade e produtividade é importante para otimizar todo o sistema produtivo, buscando animais produtivos e longevos que permitam maior lucratividade ao sistema. Assim, objetivouse avaliar, por meio da análise de multivariada, a relação de características de tipo com longevidade, contagem de células somáticas e produção de leite em bovinos da raça Holandesa no Brasil, visando a seleção indireta para estas características. Dados de produção leiteira (PL), contagem de células somáticas (CCS), longevidade e características de TIPO, obtidos do banco de dados da Associação Brasileira de Criadores de Bovinos da Raça Holandesa (ABCBRH), no período de 2000 a 2010, foram analisados utilizando técnicas estatísticas de análises uni e multivariadas. Para CCS foi considerada a média de observações de controles leiteiros da primeira lactação de cada vaca, já para PL, indicadores de produtividade foram estimados a partir de dados de controles leiteiros individuais. A longevidade foi avaliada a partir dos registros produtivos e reprodutivos, sendo selecionados dois indicadores de longevidade: produção vitalícia de leite (LONG_P) e tempo em meses entre o primeiro parto e o último controle leiteiro (LONG_T). Para as de TIPO foram utilizados os registros individuais de classificação linear de 21 características. Os valores genéticos das características foram submetidos a análise estatística multivariada afim de relacionar as características de tipo com a longevidade produtiva. Selecionar para valores genéticos intermediários de inserção de úbere anterior, colocação de tetos anterior e ligamento médio tende a diminuir a CCS. A seleção para valores genéticos intermediários para inserção anterior de úbere e angulosidade tendem a aumentar o valor genético para LONG_T. Observa-se que animais com valores genéticos positivos e elevados de largura de garupa, largura de úbere posterior e inserção anterior de úbere; valores genéticos negativos para profundidade de úbere e valores genéticos intermediários para profundidade corporal, ângulo de garupa, pernas vista lateral, inserção anterior de úbere e ligamento médio; tendem a aumentar valor genético de PL. Esses resultados sugerem uma possibilidade de seleção indireta através de TIPO, sendo necessário encontrar um equilíbrio entre PL, CCS e LONG_P que efetivem um incremento na produtividade sem causar decréscimo em características funcionais ou de tipo desejáveis nos rebanhos.

Scheid, Angelica Leticia. Functional, productive and type characteristics in Holstein breed in Brazil a multivariate approach. 2019. 75 p. Dissertation (Animal Science Masters Degree Area: Animal Production) - Universidade do Estado de Santa Catarina. Post-Graduation Program in Animal Science, Lages, 2019. An evaluation of the conversion ratio of the dairy cow with its capacity and efficiency is important to optimize the entire production system, searching productive and long-lived animals that allow greater profitability to the system. The objective of this study was to evaluate, through multivariate analysis, the genetic values of the set of the linear trait of type, to indicate those that have a greater relationship with longevity, somatic cells count and milk yield in Holstein cattle managed in Brazil, aiming at the indirect selection for these traits. Data on milk yield (PL), somatic cell count (CCS), longevity and type traits were obtained from the Brazilian Association of Breeders of Holstein Cattle (ABCBRH) in the period from 2000 to 2010 and were analyzed using univariate and multivariate analyses. For somatic cell count, the average of observations of dairy controls forms the first lactation of each cow was considered. To the milk production, productivity indicators were estimated from individual test day data. For longevity, from the productive and reproductive records, two longevity indicators were selected: lifetime milk yield (LONG_P) and time in months between the first parity and the last milk control (LONG_T). For linear type trait, individual records of linear classification for 21 traits were used. The genetic values of traits were subjected to multivariate statistical analysis in order to relate the type traits to productive longevity. Selecting intermediate genetic values of anterior udder insertion, anterior teat placement and middle ligament tends to decrease CCS. The selection of intermediate genetic values for anterior insertion of under and angularity tends to increase the genetic value of LONG_T. It is observed that animals with positive and high genetic values of rump width, posterior udder width and anterior udder insertion, negative genetic values of udder depth, and intermediate genetic values of body depth, rump angle, legs side view, anterior insertion of the udder and middle ligament tend to increase the genetic value of PL. These results suggest a possibility of indirect selection through type trait being necessary to find a balance between PL, CCS and LONG_P that effectively promote increased productivity without causing a decrease in the functional or desirable trait in the herd.

HORMÔNIO ANTI-MULLERIANO E DESEMPENHO NA PRODUÇÃO IN VITRO DE EMBRIÕES EM FÊMEAS DA RAÇA GIR (Bos indicus)

O hormônio anti-mülleriano (AMH) tem sido proposto como critério para otimizar a PIVE (Produção In Vitro de Embriões) em bovinos. Contudo, não há parâmetros claros para o uso do AMH como critério para a seleção de doadoras de oócitos. Dessa forma, o objetivo deste estudo foi avaliar a concentração plasmática de AMH como potencial marcador para a seleção de fêmeas com maior eficiência na PIVE. Novilhas pré-púberes (n=120) foram submetidas à contagem folicular antral (CFA) e à coleta de sangue para análise de AMH. As associações entre AMH e CFA, resultados de PIVE (n=506) e valor genômico, foram estimadas. A concentração plasmática de AMH foi analisada, usando-se a curva característica de operação do receptor (ROC). Em seguida, verificou-se o valor de corte que resultaria em um aumento na média para a produção de oócitos totais, viáveis e embriões. Por fim, utilizaram-se dados de PIVE de doadoras (n=658) com valores genômicos conhecidos para a produção de leite (GPTAm) e idade ao primeiro parto (GPTAafc) para determinar a associação entre os valores genômicos e os indicadores de sucesso na PIVE. Em média, as novilhas apresentaram CFA de 31,2 ± 1,1 e AMH de 932,9 ± 48,4 ng/mL e produziram 32,3 ± 1,5 oócitos totais, 25,9 ± 1,4 oócitos viáveis e 5,3 ± 0,4 embriões por sessão OPU-PIVE. Observou-se correlação positiva e moderada entre AMH e CFA, oócitos totais, oócitos viáveis e embriões produzidos, mas não com GPTAm ou GPTAafc. A área sob a curva ROC (AUC) para oócitos totais, oócitos viáveis e embriões produzidos foi de 0,77 (P<0,0001), 0,75 (P <0,0001) e 0,72 (P = 0,0003), e os pontos de corte estimados para a concentração de AMH foram 761,4, 622,5 e 681,5 pg/mL, respectivamente. Após exclusões de doadores com valores de AMH menores, as médias foram maiores (P <0,05) em um valor de corte de 632,4 pg/mL para oócitos totais, 672,3 pg/mL para oócitos viáveis e 776,8 pg/mL para embriões produzidos. Portanto, a concentração de AMH pode ser usada como marcador para selecionar doadoras com maior produção de oócitos e embriões e, assim, aumentar os resultados de PIVE em novilhas Gir. A seleção de doadoras Gir com base no rendimento de oócitos pode resultar em um aumento baixo, mas positivo, no GPTAm do rebanho. Entretanto, não apresenta relação com a idade ao primeiro parto

The anti-Mullerian hormone (AMH) has been proposed as a criterion to optimize IVEP (In Vitro Embryo Production) in cattle. However, there are no clear parameters for the use of AMH as a criterion for the selection of oocyte donors. Thus, the aim of this study was to evaluate the plasma concentration of AMH as a potential marker for the selection of females with greater efficiency in IVEP. Pre-pubertal heifers (n = 120) were submitted to blood collection for AMH analysis and antral follicle count (AFC). The associations between AMH and AFC, IVEP results (n = 506) and genomic value were estimated. The plasma AMH concentration was analyzed using the receiver operating characteristic curve (ROC). Then, the cutoff value that would result in an increase in the average for the production of total, viable oocytes and embryos was verified. Finally, IVEP data from donors (n = 658) with known genomic values for milk production (GPTAm) and age at first calve (GPTAafc) were used to determine the association between genomic values and success indicators in IVEP. On average, heifers presented AFC of 31.2 ± 1.1 and AMH of 932.9 ± 48.4 ng / mL and produced 32.3 ± 1.5 total oocytes, 25.9 ± 1.4 viable oocytes and 5.3 ± 0.4 embryos per OPU-IVEP session. A positive and moderate correlation was observed between AMH and AFC, total oocytes, viable oocytes and produced embryos, but not with GPTAm or GPTAafc. The area under the ROC curve (AUC) for total oocytes, viable oocytes and embryos produced was 0.77 (P <0.0001), 0.75 (P <0.0001) and 0.72 (P = 0, 0003), and the cutoff velues estimated for the AMH concentration were 761.4, 622.5 and 681.5 pg / mL, respectively. After exclusions from donors with lower AMH values, the averages were higher (P <0.05) at a cutoff value of 632.4 pg / mL for total oocytes, 672.3 pg / mL for viable oocytes and 776.8 pg / mL for produced embryos. Therefore, the concentration of AMH can be used as a marker to select donors with higher production of oocytes and embryos and, thus, increase the results of IVEP in Gir heifers. Selection of Gir donors based on oocyte yield may result in a low, but positive, increase in herd GPTAm. However, it is not related to age at first delivery

ESTIMATIVA DE PARÂMETROS DE CURVA DE LACTAÇÃO E DESEMPENHO PRODUTIVO DE VACAS DA RAÇA GIROLANDO

A maior parte da produção de leite nacional advém de animais da raça Girolando, portanto é necessário obter parâmetros que possibilitem tomadas de decisões acerca do desempenho dos rebanhos, seja realizado ao aumento da produção, bem como a produtividade, priorizando os programas de melhoramento genético. A utilização de modelos de regressão aleatória melhora a acurácia das avaliações genéticas e fornece um ótimo mecanismo para avaliar a persistência na lactação. A persistência na lactação está diretamente relacionada a aspectos econômicos da atividade leiteria e a melhoria desta pode contribuir para a redução de custos no sistema de produção. Com intuito de estudar a viabilidade da utilização da característica persistência na lactação em avaliação genética, em gado de leite, uma vez que são escassos os estudos sobre este assunto, principalmente em condições tropicais, objetivou-se, neste trabalho, avaliar o modelo matemático Wood que descreve a curva de lactação. Os dados de produção de leite até 305 dias da lactação eram de 29.095 vacas de primeira lactação, com partos ocorridos entre os anos 1988 a 2014, pertencentes ao Arquivo Zootécnico do Centro Nacional de Pesquisa em Gado de Leite da Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA/CNPGL). A análise foi feita pelo critério de coeficiente de determinação ajustado (R²A) dos parâmetros utilizando o modelo de Wood 1967, apresentou o R²A 78,06 indica um bom ajuste aos dados de produção de leite.

Most of the national milk production comes from Girolando cattle, so it is necessary to obtain parameters to make decisions about the performance of the herds, to be carried out to increase production, as well as productivity, prioritizing breeding programs. The use of random regression models improves the accuracy of genetic evaluations and provides a good mechanism to evaluate persistence in lactation. The persistence in lactation is directly related to economic aspects of the dairy activity and the improvement of this can contribute to the reduction of costs in the production system. In order to study the viability of the use of the characteristic persistence in lactation in genetic evaluation in milk cattle, since studies on this subject are scarce, especially in tropical conditions, the objective of this study was to evaluate the mathematical model Wood that describes the lactation curve. The milk production data up to 305 days of lactation were 29,095 lactating cows, with calving occurring between 1988 and 2014, belonging to the Zootechnical Archive of the National Center for Research in Milk Cattle of the Brazilian Agricultural Research Corporation (EMBRAPA / CNPGL). The analysis was performed using the criterion of adjusted coefficient of determination (R²A) of the parameters using the model of Wood 1967, presented the R²A 78.06 indicates a good adjustment to the data of milk production.

Desempenho, características de carcaça e qualidade de carne de bovinos Nelore com diferentes potenciais genéticos para crescimento pósdesmama

O objetivo do presente estudo foi avaliar o desempenho, características de carcaça e qualidade de carne de bovinos Nelore com diferentes potenciais genéticos para crescimento pós-desmama pela diferença esperada na progênie (DEP). Foram utilizados 147 machos não-castrados da raça Nelore, com peso corporal médio inicial de 412 ± 54kg e média de idade de 19 meses, provenientes de recria em sistema de pastejo contínuo. Os animais foram distribuídos em um delineamento inteiramente casualizado e divididos dois tratamentos em função do potencial genético para crescimento: 1) alta taxa de crescimento (TC+) representada pela média de 11,50 kg e 2) baixa taxa de crescimento (TC-) representada pela média de 1,0 kg. Os animais foram confinados por um período de 100 dias, sendo os primeiros 21 dias de adaptação à dieta e as instalações. A dieta continha 73% de concentrado e 27% de volumoso (silagem de milho). No início do período experimental e a cada 28 dias todos os animais foram pesados e submetidos a avaliações de ultrassonografia. A ingestão de matéria seca foi avaliada diariamente, para ajuste da oferta e avaliação da eficiência alimentar. Ao fim do período de confinamento, todos animais foram abatidos, o peso de carcaça quente e a gordura pélvica, renal e inguinal foram pesados. Após 24 horas, foi avaliado o pH final e a meia carcaça esquerda foi seccionada entre a 12ª e 13ª costelas. As meias carcaças seguiram para desossa completa para análise de rendimentos dos cortes cárneos comerciais, em seguida amostras foram retiradas do contrafilé para posterior análise de cor, perdas de peso por cozimento, força de cisalhamento, comprimento de sarcômero e análise sensorial. Houve efeito da TC sobre o peso corporal final (P = 0,04) sendo que os animais de alta TC apresentaram maiores pesos. Não houve efeito da TC para AOL, EGS e espessura de gordura da picanha (Biceps femoris) avaliados pela ultrassonografia; no entanto, houve diferença significativa para o período de coleta das imagens (P < 0,05). Com relação ao rendimento dos cortes cárneos comerciais, animais de alta TC tiveram a ponta de peito (P = 0,01) e músculo traseiro (P = 0,07) mais pesados em relação aos animais de baixa TC. A DEP não influenciou a qualidade das características sensoriais da carne dos animais exceto para a cor, sendo que os valores de L* (P = 0,03) foram maiores para animais de baixa TC, no entanto, os maiores valores de a* (P = 0,06) foram expressados pelo grupo de alta TC. Além disso, para todas as variáveis de qualidade, houve efeito do tempo de maturação (P > 0,05). Em conclusão, o potencial genético para o crescimento pós-desmama não afetou a maioria das características, incluindo desempenho, produção de carne e qualidade no final do período de terminação.

The aim of this study was to evaluated the performance, carcass characteristics and meat quality of Nellore young bulls with different genetics potentials for post-weaning growth for expected progeny differences (EPDs). A total of147 Nellore bulls with average initial body weight (412 ± 54kg) and 19 months old, were distributed in a completely randomized design and divided into two groups according with growth rate: 1) high growth rate (GR+) represented by the mean of 11.50 kg and 2) low growth rate (GR-) represented by the average of -1.0 kg . The animals were in a feedlot system for a total 100 days, with the first 21 days of adaptation to the diet and facilities. The finishing diet was composed by 73 % concentrate and 27 % corn silage. At the beginning of the experimental period and every 28 days all animals were weighed and submitted to ultrasound evaluations. Dry matter intake was measured daily. At the end of the feedlot period, all animals were slaughtered and the hot carcass weigth and internal fat were recorded. After 24 hours, the final pH was evaluated and the left half carcass was sectioned between the 12 th and 13 th ribs. The half carcass was completely deboning to analyze the wholesale cuts. In addition, longissimus was sampled to analyze color, cooking loss, tenderness, sarcomere length and sensory property. There was an effect of GR on the final body weight (P = 0.04), where the group of animals with high EPD presented higher weights. There was no effect of GR for longissimus muscle area (LMA), fat thickness (FAT) and rump fat (Biceps femoris) evaluated by ultrasonography; however, there was a significant difference for the collection period (P > 0.05). Regarding the wholesale cuts, animals of higher GR had the heavier (P = 0.01) and hind muscle (P = 0.07) weights than the animals of lower GR. The GR did not influence the quality sensory characteristics of the meat of the animals except for the color, and the values of L* (P = 0.03) were higher for animals with low GR, however, the highest values of a* (P = 0.06) were expressed by the high GR group. In addition, for all quality variables, there was an effect of maturation time (P > 0.05). In conclusion, the potential genetic for growth measured post-weaning did not affect most traits, including performance, meat production and quality at the end of finishing period.