Applying assisted reproductive technology and reproductive management to reduce CO2-equivalent emission in dairy and beef cattle: a review

Methane emission from beef and dairy cattle combined contributes around 4.5-5.0% of total anthropogenic global methane. In addition to enteric methane (CH4) produced by the rumen, cattle production also contributes carbon dioxide (CO2) (feed), nitrous oxide (N2O) (feed production, manure) and other CH4 (manure) to the total greenhouse gas (GHG) budget of beef and dairy production systems. The relative contribution in standard dairy systems is typically enteric CH4 58%, feed 29% and manure 10%. Herds with low production efficiency can have an enteric CH4 contribution up to 90%. Digestibility of feed can impact CH4 emission intensity. Low fertility herds also have a greater enteric CH4 contribution. Animals with good feed conversion efficiency have a lower emission intensity of CH4/kg of meat or milk. Feed efficient heifers tend to be lean and have delayed puberty. Fertility is a major driver of profit in both beef and dairy cattle, and it is highly important to apply multi-trait selection when shifting herds towards improved efficiency and reduced CH4. Single nucleotide polymorphisms (SNPs) have been identified for feed efficiency in cattle and are used in genomic selection. SNPs can be utilized in artificial insemination and embryo transfer to increase the proportion of cattle that have the attributes of efficiency, fertility and reduced enteric CH4. Prepubertal heifers genomically selected for favourable traits can have oocytes recovered to produce IVF embryos. Reproductive technology is predicted to be increasingly adopted to reduce generation interval and accelerate the rate of genetic gain for efficiency, fertility and low CH4 in cattle. The relatively high contribution of cattle to anthropogenic global methane has focussed attention on strategies to reduce enteric CH4 without compromising efficiency and fertility. Assisted reproductive technology has an important role in achieving the goal of multiplying and distributing cattle that have good efficiency, fertility and low CH4.(AU)

Genetic parameters for growth, reproductive, and carcass traits in Tabapuã cattle

We aimed to estimate genetic parameters for growth, reproductive, and carcass traits in Tabapuã cattle. Phenotypic data were collected between 1990 and 2019 in 1,218 farms, and the pedigree file had 340,868 animals. The traits evaluated were body weight at 120 (W120), 210 (W210), 365 (W365), and 550 (W550) days of age; age at first calving (AFC), scrotal circumference at 365 days of age (SC365), ribeye area (REA), backfat thickness (BF), and rump fat thickness (RF). The (co)variance components were estimated using the restricted maximum likelihood method, considering single and two-traits animal models. For all traits, the models considered fixed, direct additive genetic, and residual random effects. In addition, for W120 and W210, the maternal additive genetic and maternal permanent environmental effects were also included. Heritabilities for W120, W210, W365, W550, SC365, REA, BF, and RF were of moderate magnitude (0.15, 0.16, 0.23, 0.19, 0.22, 0.36, 0.31, and 0.27, respectively). Low heritability was observed for AFC (0.07). The genetic correlations between growth traits were higher than 0.90, while AFC and SC365 presented negative moderate correlation (−0.66). The REA showed low genetic correlations with BF (0.07) and RF (0.07), whereas BF and RF were highly correlated (0.77). Considering the heritability estimates, selection for AFC would result in limited genetic gain, while for the other traits, it would be satisfactory. Based on the high genetic correlations between growth traits, selection of Tabapuã animals can be performed at younger ages. Additionally, animals can be indirectly selected for AFC through SC365, and only one fat thickness trait may be used in the selection process considering the high genetic correlation and similar heritability values for BF and RF.(AU)

Coexistence of endemic peacock basses (Cichla) in a Neotropical reservoir (Cichlidae: Cichliformes)

Peacock basses (genus Cichla) are predatory fish widely distributed across the Amazon, where two or more species normally coexist in a same drainage. The mechanisms that allow coexistence remain poorly understood, although these species share a number of functional traits and behavioral aspects. To advance on this question, the present study compared population and functional traits of Cichla kelberi and C. piquiti, based on data collected between 2010 and 2020 in the upper section of the Lajeado Reservoir, Tocantins River. Both species were captured in all sampling sites, frequently in a same sample, but C. piquiti was far more frequent and abundant. The species used the same habitats, and co-occurred more often than expected by chance. Species had a similar diet (small-sized fish), reproductive effort, fecundity and fat accumulation, but C. piquiti showed larger body sizes, shoaling behavior, a longer reproductive period, and morphology associated with greater swimming potential. Overall, results revealed that these species coexist in the impoundment, with significant overlap in the use of habitats and food resources. Differences in other functional traits may favor their coexistence, possibly involving niche partitioning, which seem to explain the dominance of C. piquiti in the impoundment.(AU)

Tucunarés (gênero Cichla) são peixes predadores amplamente distribuídos pela Amazônia, sendo comum que duas ou mais espécies coexistam em uma mesma drenagem. Os mecanismos que permitem sua coexistência permanecem pouco compreendidos, embora essas espécies compartilhem uma série de traços funcionais e comportamentais. Para avançar nessa questão, o presente estudo comparou uma série de características populacionais e funcionais de Cichla kelberi e C. piquiti, com base em dados coletados entre 2010 e 2020 no reservatório de Lajeado, rio Tocantins. Ambas as espécies foram capturadas em todos os locais de amostragem, frequentemente em uma mesma amostra, mas C. piquiti foi muito mais frequente e abundante que C. kelberi. As espécies ocuparam os mesmos habitats, e co-ocorreram mais vezes do que o esperado ao acaso. As espécies apresentaram dieta (composta por peixes de pequeno porte), esforço reprodutivo, fecundidade e acúmulo de gordura semelhantes, mas C. piquiti apresentou tamanho corporal maior, comportamento de formar cardumes, período reprodutivo mais longo, e morfologia associada com maior poder de natação. No geral, os resultados revelaram que essas espécies coexistem no represamento, com sobreposição significativa no uso de habitats e recursos alimentares. Diferenças em outros traços funcionais devem favorecer sua coexistência, possivelmente envolvendo partição de nicho, o que parece explicar a dominância de C. piquiti no represamento.(AU)

Functional responses of stream fish communities to rural and urban land uses

We tested the effects of ruralization and urbanization on the functional diversity indices and the composition of functional traits of Neotropical stream fish communities. The study was carried out in 24 streams of the Pirapó, Piquiri, Paraná III and Iguassu river basins. Land use in the watershed was categorized as percentages of native vegetation, rural occupation and urban occupation. Statistical tests revealed negative bivariate correlations between functional dispersion and the proportion of native vegetation in the watershed. The results indicate that a higher percentage of rural or urban occupation is associated with increased functional dispersion. In the analyzes of trait composition, significant alterations were observed in response to urbanization while only the increase in herbivory responded to ruralization. As the area of native vegetation is reduced by urbanization, the trait composition changes, with reduced proportions of species with intolerance to hypoxia, migratory reproductive behavior, external fertilization, and subterminal mouth, and increased proportions of species with parental care, detritivory, internal fertilization, and an upper mouth. Therefore, fish species that have these specific characteristics are more likely to disappear from streams as urbanization progresses. In summary, urbanization was related to a greater change in the composition of functional traits than ruralization.(AU)

Nós testamos os efeitos da ruralização e da urbanização sobre os índices de diversidade funcional e da composição de traços funcionais em assembleias de peixes de riachos Neotropicais. Amostras foram feitas em 24 riachos distribuídos nas bacias dos rios Pirapó, Piquiri, Paraná III e Iguaçu. O uso do solo foi categorizado por meio das porcentagens de vegetação, ocupação rural e urbana. Testes estatísticos revelaram correlações negativas bivariadas entre a dispersão funcional e a proporção de vegetação. Os resultados indicaram que maior percentual de ocupação rural ou urbana está associado ao aumento da dispersão funcional. Nas análises de composição de traços foram observadas alterações significativas em resposta à urbanização, enquanto apenas o aumento de herbívoros respondeu à ruralização. À medida que a área de vegetação é reduzida, a composição de traços muda, com redução nas proporções de espécies com intolerância à hipóxia, comportamento reprodutivo migratório, fertilização externa e boca subterminal, e aumento da proporção daquelas com cuidado parental, detritivoria, fertilização interna e boca superior. Portanto, espécies que apresentam essas características têm maior probabilidade de desaparecer dos riachos à medida que a urbanização avança. Em resumo, a urbanização foi relacionada a maior alteração na composição de traços funcionais do que a ruralização.(AU)

Functional responses of stream fish communities to rural and urban land uses

We tested the effects of ruralization and urbanization on the functional diversity indices and the composition of functional traits of Neotropical stream fish communities. The study was carried out in 24 streams of the Pirapó, Piquiri, Paraná III and Iguassu river basins. Land use in the watershed was categorized as percentages of native vegetation, rural occupation and urban occupation. Statistical tests revealed negative bivariate correlations between functional dispersion and the proportion of native vegetation in the watershed. The results indicate that a higher percentage of rural or urban occupation is associated with increased functional dispersion. In the analyzes of trait composition, significant alterations were observed in response to urbanization while only the increase in herbivory responded to ruralization. As the area of native vegetation is reduced by urbanization, the trait composition changes, with reduced proportions of species with intolerance to hypoxia, migratory reproductive behavior, external fertilization, and subterminal mouth, and increased proportions of species with parental care, detritivory, internal fertilization, and an upper mouth. Therefore, fish species that have these specific characteristics are more likely to disappear from streams as urbanization progresses. In summary, urbanization was related to a greater change in the composition of functional traits than ruralization.(AU)

Nós testamos os efeitos da ruralização e da urbanização sobre os índices de diversidade funcional e da composição de traços funcionais em assembleias de peixes de riachos Neotropicais. Amostras foram feitas em 24 riachos distribuídos nas bacias dos rios Pirapó, Piquiri, Paraná III e Iguaçu. O uso do solo foi categorizado por meio das porcentagens de vegetação, ocupação rural e urbana. Testes estatísticos revelaram correlações negativas bivariadas entre a dispersão funcional e a proporção de vegetação. Os resultados indicaram que maior percentual de ocupação rural ou urbana está associado ao aumento da dispersão funcional. Nas análises de composição de traços foram observadas alterações significativas em resposta à urbanização, enquanto apenas o aumento de herbívoros respondeu à ruralização. À medida que a área de vegetação é reduzida, a composição de traços muda, com redução nas proporções de espécies com intolerância à hipóxia, comportamento reprodutivo migratório, fertilização externa e boca subterminal, e aumento da proporção daquelas com cuidado parental, detritivoria, fertilização interna e boca superior. Portanto, espécies que apresentam essas características têm maior probabilidade de desaparecer dos riachos à medida que a urbanização avança. Em resumo, a urbanização foi relacionada a maior alteração na composição de traços funcionais do que a ruralização.(AU)

Genetic parameters and trends for reproductive traits in Blanco Orejinegro cattle from Colombia / Parâmetros e tendências genéticas para características reprodutivas no gado Blanco Orejinegro da Colômbia

The Colombian creole cattle breed Blanco Orejinegro (BON) is an important zoogenetic resource, but there is little knowledge about the genetic parameters and trends of its reproductive traits. Therefore, the aim of this study was to estimate parameters for the reproductive traits calving interval (CI), age at first calving (AFC), gestation duration (GD) and genetic trends for CI in the BON breed. Genealogy information from 7,799 animals was used, and employing the MTDFREML program, the components of the variance, heritability (h2), repeatability (rep), and estimated breeding values (EBV) for CI (n=3308), AFC (n=729), and GD (n=306) were estimated, in addition to the inbreeding coefficient (F) of the population. Genetic trends were established through linear regression using R software. Finally, the animals were classified as inbred (F > 0) and noninbred (F=0), and the effect of inbreeding on reproductive performance was established through a generalized linear model using the R program. An average F value of 4.41%±0.06 was observed. The h2 for CI was 0.11±0.03 with a rep of 0.15±0.04; for AFC, h2 was 0.00±0.05; and for GD, h2 was 0.00±0.08. The genetic trend for CI was -0.01 days/year. Finally, for CI, inbreeding depression was evident; this trait increased when inbreeding increased. These results indicate an important environmental influence on reproductive traits. The heritability estimate for CI suggests that little genetic progress could be achieved through selection. The evidence of inbreeding depression raises the need to control inbreeding to conserve this genetic resource.(AU)

O gado crioulo colombiano Blanco Orejinegro (BON) é um importante recurso zoogenético, mas ainda há desconhecimento sobre os parâmetros e tendências genéticas das características reprodutivas dessa raça. Portanto, o objetivo deste estúdio foi estimar parâmetros e tendências genéticas para características reprodutivas intervalo de partos (IDP), idade ao primeiro parto (IPP) e duração da gestação (DG) na raça BON. A informação da genealogia de 7,799 animais foi usada. Utilizando o programa MTDFREML foram estimados os componentes de variância, herdabilidade (h2), repetibilidade (rep) e valores genéticos (VGE), para IDP (n=3308), IPP (n=729) e DG (n=306), além do coeficiente de endogamia (F) na população. As tendências genéticas foram determinadas por regressão linear usando o software R. Finalmente, os animais foram classificados como endogâmicos (F > 0) e não endogâmicos (F=0) e o efeito da endogamia no desempenho reprodutivo foi determinado usando um modelo linear generalizado usando R. Observouse um F médio de 4,41%+0,06. A h2 para IDP foi 0,11±0,03 com uma repetibilidade de 0,15±0,04; para IPP a h2 foi 0,00 ± 0,05; e para DG a h2 foi 0,00 ± 0,08. A tendência genética para IDP foi -0,01 dias/ano. Finalmente, para o IDP, a depressão por endogamia foi evidente, aumentando o IDP com o aumento da endogamia. Os resultados indicam uma importante influência ambiental nas características reprodutivas. A herdabilidade estimada para o IDP sugere que pouco ganho genético pode ser alcançado através da seleção, embora a depressão endogâmica evidencie a necessidade de controlar a consanguinidade para conservar o recurso genético.(AU)

Cox-Gompertz model for analysis of the time of stay in an Anglo-Nubian goat herd / Modelo de Cox-Gompertz para análise do tempo de permanência em um rebanho de cabras da raça Anglonubiana

Anglo-Nubian goats are hardy animals able to adapt to tropical environments, where their farming is usually held on pasture. However, climatic conditions in this environment also favor endoparasitism, which implies a negative aspect if sensitivity to worm infections interferes by reducing the reproductive lifespan of females, as their stay in the herd is a trait of great importance for efficient goat farming. In this respect, this study proposes to use the survival analysis methodology with the Cox-Gompertz proportional hazards model to assess the length of stay in the herd by relating the removal of females due to death with worm infection being the main cause to other forms of culling, using information from 101 Anglo-Nubian goats born from2009 to 2013 in an experimental herd from Teresina - PI, Brazil. The Cox-Gompertz proportional hazards model chose body condition score, birth weight and birth season as important covariates (p-value ≤ 10%). Body condition score showed to be a favorable factor for the longer stay of the goats in the herd. Eggs per gram, age at first kidding, birth type and dam age were not significant. The Cox-Gompertz proportional hazards model is suitable for fitting the statistical model to estimate the length of stay in the herd, with censoring related to endoparasitism in Anglo-Nubian goats.

Os caprinos da raça Anglonubiana apresentam-se rústicos com adaptabilidade a ambiente tropical, onde sua exploração ocorre geralmente em pasto. Entretanto, condições climáticas desse ambiente favorecem também o endoparasitismo, implicando num aspecto negativo se a sensibilidade a verminoses interferir reduzindo a duração da vida reprodutiva de fêmeas, pois a permanência delas no rebanho é uma característica de grande importância para a maior eficiência da caprinocultura. Neste contexto, objetiva-se com este estudo utilizar a metodologia de análise de sobrevivência com modelo de riscos proporcionais de Cox-Gompertz para avaliação do tempo permanência no rebanho, relacionando a saída da fêmea por morte tendo a verminose como a principal causa, em relação a outras formas de descarte, utilizando-se informações de 101 cabras da raça Anglonubiana nascidas no período de 2009 a 2013 em rebanho experimental localizado em Teresina-Piauí. O modelo de riscos proporcionais de Cox-Gompertz, elegeu como covariáveis importantes (p-valor ≤ 10%): o escore da condição corporal (ECC), o peso ao nascer(PN) e a estação de nascimento (EN). O ECC se apresentou como fator favorável a maior permanência das cabras no rebanho. Não foram significativos o OPG, idade ao primeiro parto, tipo de nascimento e idade da mãe. O modelo de riscos proporcionais de Cox-Gompertz se mostra adequado no ajuste do modelo estatístico para estimar o tempo de permanência no rebanho, com censura relacionada a endoparasitismo em cabras da raça Anglonubiana.

Cox-Gompertz model for analysis of the time of stay in an Anglo-Nubian goat herd / Modelo de Cox-Gompertz para análise do tempo de permanência em um rebanho de cabras da raça Anglonubiana

Anglo-Nubian goats are hardy animals able to adapt to tropical environments, where their farming is usually held on pasture. However, climatic conditions in this environment also favor endoparasitism, which implies a negative aspect if sensitivity to worm infections interferes by reducing the reproductive lifespan of females, as their stay in the herd is a trait of great importance for efficient goat farming. In this respect, this study proposes to use the survival analysis methodology with the Cox-Gompertz proportional hazards model to assess the length of stay in the herd by relating the removal of females due to death with worm infection being the main cause to other forms of culling, using information from 101 Anglo-Nubian goats born from2009 to 2013 in an experimental herd from Teresina - PI, Brazil. The Cox-Gompertz proportional hazards model chose body condition score, birth weight and birth season as important covariates (p-value ≤ 10%). Body condition score showed to be a favorable factor for the longer stay of the goats in the herd. Eggs per gram, age at first kidding, birth type and dam age were not significant. The Cox-Gompertz proportional hazards model is suitable for fitting the statistical model to estimate the length of stay in the herd, with censoring related to endoparasitism in Anglo-Nubian goats.(AU)

Os caprinos da raça Anglonubiana apresentam-se rústicos com adaptabilidade a ambiente tropical, onde sua exploração ocorre geralmente em pasto. Entretanto, condições climáticas desse ambiente favorecem também o endoparasitismo, implicando num aspecto negativo se a sensibilidade a verminoses interferir reduzindo a duração da vida reprodutiva de fêmeas, pois a permanência delas no rebanho é uma característica de grande importância para a maior eficiência da caprinocultura. Neste contexto, objetiva-se com este estudo utilizar a metodologia de análise de sobrevivência com modelo de riscos proporcionais de Cox-Gompertz para avaliação do tempo permanência no rebanho, relacionando a saída da fêmea por morte tendo a verminose como a principal causa, em relação a outras formas de descarte, utilizando-se informações de 101 cabras da raça Anglonubiana nascidas no período de 2009 a 2013 em rebanho experimental localizado em Teresina-Piauí. O modelo de riscos proporcionais de Cox-Gompertz, elegeu como covariáveis importantes (p-valor ≤ 10%): o escore da condição corporal (ECC), o peso ao nascer(PN) e a estação de nascimento (EN). O ECC se apresentou como fator favorável a maior permanência das cabras no rebanho. Não foram significativos o OPG, idade ao primeiro parto, tipo de nascimento e idade da mãe. O modelo de riscos proporcionais de Cox-Gompertz se mostra adequado no ajuste do modelo estatístico para estimar o tempo de permanência no rebanho, com censura relacionada a endoparasitismo em cabras da raça Anglonubiana.(AU)

Potencial reprodutivo (PR) de touros Nelore avaliados por parâmetros andrológicos e comportamento sexual. Classificação por pontos: nova proposição / [Reproductive potential of Nelore bulls evaluated by andrological parameters and sexual behavior. Classification by points - a new proposition]

Este estudo teve por objetivo comparar variações de parâmetros andrológicos e comportamentais de touros Nelore de diferentes faixas etárias, calcular seu potencial reprodutivo (PR) e propor uma nova tabela de classificação por pontos, de acordo com as médias atualmente alcançadas por eles nas características estudadas. Foram utilizados dados de 6162 exames andrológicos de touros da raça Nelore, entre 12 e 80 meses de idade, em regime de monta natural. O número de touros classificados como aptos consistiu em 88,9% dos animais avaliados (n=5480), sendo 51,6% desses considerados excelentes (n=2827), 41,2% muito bons (n=2257) e 7,2% considerados bons (n=394). Entre os animais questionáveis (n=682; 11,1%), 79,6% foram classificados como inaptos temporários (n=542) e 20,4% (n=139) como animais descarte, de acordo com o exame andrológico, independentemente do teste da libido. O número de touros classificados como excelentes se reduziu para 752 (12,2%) quando dados de comportamento sexual foram incluídos para definição do seu PR. Concluiu-se que o uso de tabelas de classificação andrológica por pontos com atualizações técnicas beneficia a seleção mais apurada de touros Nelore. O teste da libido é ferramenta importante para a determinação do PR, o qual permite melhor aproveitamento dos reprodutores.(AU)

This study aimed to compare variations of andrological and behavioral parameters from Nelore bulls of different ages, to calculate their reproductive potential (RP) and propose a new classification table by points, considering current averages in each reproductive trait studied. Data were collected from 6162 breeding soundness examinations of Nelore bulls aged between 12 and 80 months, under natural mating. According to andrological parameters, regardless of the libido test, the number of bulls classified as approved was 88.9% (n= 5480), being 51.6% considered as excellent (n= 2827), 41.2% very good (n= 2257) and 7.2% considered as good (n= 394). Among the animals considered as questionable (n= 682; 11.1%), 79.6% were classified as temporarily reproved (n= 542) and 20.4% (n= 139) as discarded animals. The number of bulls classified as excellent decreased to 752 (12.2%) when sexual behavior data were included to define their RP. It was concluded that the use of tables for andrological classification by points with technical updates improves the reproductive selection of Nelore bulls. The libido test is an important tool for RP determination which provides better utilization of the sires.(AU)

Potencial reprodutivo (PR) de touros Nelore avaliados por parâmetros andrológicos e comportamento sexual. Classificação por pontos: nova proposição / [Reproductive potential of Nelore bulls evaluated by andrological parameters and sexual behavior. Classification by points - a new proposition]

Este estudo teve por objetivo comparar variações de parâmetros andrológicos e comportamentais de touros Nelore de diferentes faixas etárias, calcular seu potencial reprodutivo (PR) e propor uma nova tabela de classificação por pontos, de acordo com as médias atualmente alcançadas por eles nas características estudadas. Foram utilizados dados de 6162 exames andrológicos de touros da raça Nelore, entre 12 e 80 meses de idade, em regime de monta natural. O número de touros classificados como aptos consistiu em 88,9% dos animais avaliados (n=5480), sendo 51,6% desses considerados excelentes (n=2827), 41,2% muito bons (n=2257) e 7,2% considerados bons (n=394). Entre os animais questionáveis (n=682; 11,1%), 79,6% foram classificados como inaptos temporários (n=542) e 20,4% (n=139) como animais descarte, de acordo com o exame andrológico, independentemente do teste da libido. O número de touros classificados como excelentes se reduziu para 752 (12,2%) quando dados de comportamento sexual foram incluídos para definição do seu PR. Concluiu-se que o uso de tabelas de classificação andrológica por pontos com atualizações técnicas beneficia a seleção mais apurada de touros Nelore. O teste da libido é ferramenta importante para a determinação do PR, o qual permite melhor aproveitamento dos reprodutores.(AU)

This study aimed to compare variations of andrological and behavioral parameters from Nelore bulls of different ages, to calculate their reproductive potential (RP) and propose a new classification table by points, considering current averages in each reproductive trait studied. Data were collected from 6162 breeding soundness examinations of Nelore bulls aged between 12 and 80 months, under natural mating. According to andrological parameters, regardless of the libido test, the number of bulls classified as approved was 88.9% (n= 5480), being 51.6% considered as excellent (n= 2827), 41.2% very good (n= 2257) and 7.2% considered as good (n= 394). Among the animals considered as questionable (n= 682; 11.1%), 79.6% were classified as temporarily reproved (n= 542) and 20.4% (n= 139) as discarded animals. The number of bulls classified as excellent decreased to 752 (12.2%) when sexual behavior data were included to define their RP. It was concluded that the use of tables for andrological classification by points with technical updates improves the reproductive selection of Nelore bulls. The libido test is an important tool for RP determination which provides better utilization of the sires.(AU)

Genetic evaluation of milking buffaloes (Bubalus bubalis): bull ranking / Avaliação genética de búfalas leiteiras (Bubalus bubalis): classificação de touros

The objective of this study was to evaluate genetic aspects related to production and reproductive efficiency of Murrah and Mediterranean buffaloes and their crosses. A ranking of bulls from Embrapa Eastern Amazonia was also composed to guide assisted mating. Birth records of 2,322 Murrah, Mediterranean, and crossbred buffaloes from the Embrapa Eastern Amazon herd, from 1953 to 2013, as well as information on production and reproductive traits were used. Genetic analyzes were performed in the WOMBAT software using the animal model with two-trait analysis. While heritability (h2) for total milk production (TMP) and fat milk percentage (F) were generally high, for reproductive traits h2 tended to be low. Genetic correlations for TMP with the other traits were low and negative, except for TMP with calving interval (CI) and service period (SP) in the Mediterranean breed and with age at first calving (AFC) and SP in crossbred, which were positive and high. Bull 1001 had high predicted transmitting ability (PTA) for TMP, so it should transmit a greater volume of milk to his offspring, although it had a lower PTA for F. There was sufficient variability within the herd to work with genetic management for both production and reproductive efficiency.(AU)

O objetivo deste estudo foi avaliar os aspectos genéticos relacionados à produção e à eficiência reprodutiva de búfalas das raças Murrah, Mediterrâneo e suas cruzas. Uma classificação de touros da Embrapa Amazônia Oriental também foi composta para orientar os cruzamentos assistidos. Foram utilizados 2.322 registros de nascimento de búfalas das raças Murrah, Mediterrâneo e cruzadas do rebanho da Embrapa Amazônia Oriental, de 1953 a 2013, bem como características produtivas e reprodutivas. As análises genéticas foram realizadas pelo software Wombat, utilizando-se o modelo animal com análise de duas características. Enquanto a herdabilidade (h 2 ) para a produção total de leite (PTL) e para a porcentagem de gordura (G) foi alta, para as características reprodutivas a h 2 tendeu a ser baixa. As correlações genéticas da PTL com as demais características foram baixas e negativas, exceto para a PTL com intervalo entre partos (IP) e período de serviço (PS) na raça Mediterrâneo e com idade ao primeiro parto (IPP) e PS nas cruzadas, que foram positivas e altas. O touro 1001 apresentou alta capacidade de transmissão predita (CTP) para a PTL, então deve transmitir um maior volume de leite para seus descendentes, embora com um menor conteúdo transmissível de CTP para G. Portanto, existe variabilidade suficiente dentro do rebanho para trabalhar com o manejo genético para a produção e a eficiência reprodutiva.(AU)

Genetic evaluation of milking buffaloes (Bubalus bubalis): bull ranking / Avaliação genética de búfalas leiteiras (Bubalus bubalis): classificação de touros

The objective of this study was to evaluate genetic aspects related to production and reproductive efficiency of Murrah and Mediterranean buffaloes and their crosses. A ranking of bulls from Embrapa Eastern Amazonia was also composed to guide assisted mating. Birth records of 2,322 Murrah, Mediterranean, and crossbred buffaloes from the Embrapa Eastern Amazon herd, from 1953 to 2013, as well as information on production and reproductive traits were used. Genetic analyzes were performed in the WOMBAT software using the animal model with two-trait analysis. While heritability (h2) for total milk production (TMP) and fat milk percentage (F) were generally high, for reproductive traits h2 tended to be low. Genetic correlations for TMP with the other traits were low and negative, except for TMP with calving interval (CI) and service period (SP) in the Mediterranean breed and with age at first calving (AFC) and SP in crossbred, which were positive and high. Bull 1001 had high predicted transmitting ability (PTA) for TMP, so it should transmit a greater volume of milk to his offspring, although it had a lower PTA for F. There was sufficient variability within the herd to work with genetic management for both production and reproductive efficiency.(AU)

O objetivo deste estudo foi avaliar os aspectos genéticos relacionados à produção e à eficiência reprodutiva de búfalas das raças Murrah, Mediterrâneo e suas cruzas. Uma classificação de touros da Embrapa Amazônia Oriental também foi composta para orientar os cruzamentos assistidos. Foram utilizados 2.322 registros de nascimento de búfalas das raças Murrah, Mediterrâneo e cruzadas do rebanho da Embrapa Amazônia Oriental, de 1953 a 2013, bem como características produtivas e reprodutivas. As análises genéticas foram realizadas pelo software Wombat, utilizando-se o modelo animal com análise de duas características. Enquanto a herdabilidade (h 2 ) para a produção total de leite (PTL) e para a porcentagem de gordura (G) foi alta, para as características reprodutivas a h 2 tendeu a ser baixa. As correlações genéticas da PTL com as demais características foram baixas e negativas, exceto para a PTL com intervalo entre partos (IP) e período de serviço (PS) na raça Mediterrâneo e com idade ao primeiro parto (IPP) e PS nas cruzadas, que foram positivas e altas. O touro 1001 apresentou alta capacidade de transmissão predita (CTP) para a PTL, então deve transmitir um maior volume de leite para seus descendentes, embora com um menor conteúdo transmissível de CTP para G. Portanto, existe variabilidade suficiente dentro do rebanho para trabalhar com o manejo genético para a produção e a eficiência reprodutiva.(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.(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.

Life-history traits of Farlowella hahni (Siluriformes, Loricariidae) in streams of the Ivinhema River Basin, Upper Paraná Basin / Traços de história de vida de Farlowella hahni (Siluriformes, Loricariidae) em riachos da Bacia do rio Ivinhema, Bacia do alto Paraná

Brazilian laws allow the catch of some species as ornamental fish; however, in the absence of biological information, such catch can threaten species conservation. Therefore, this study aimed to offer population and reproductive information about Farlowella hahni in streams of the Ivinhema River Basin, Upper Paraná Basin. To accomplish this, a total of 165 F. hahni individuals were analyzed, including 109 females and 48 males, resulting in an important sex ratio difference from 1:1 ( 2=19.97; p 0.001), indicating a predominance of females throughout the year. Females reach higher standard length than males. Males presented isometric Length-Weight Relationships, while females have positive allometric growth. Gonadosomatic index presented higher values from October through December. The mean fecundity was 100.3±36.4 of vitellogenic oocytes and was positively correlated with standard length (r=0.51; p=0.01). The data presented herein are the first for this species and suggest a need to carefully manage the F. hahni population, considering its low abundance and fecundity.(AU)

As leis brasileiras permitem a captura de algumas espécies de peixes como ornamentais, no entanto, a ausência de informações biológicas pode tornar esta captura uma ameaça para a conservação destas espécies. Este estudo teve como objetivo oferecer informações populacionais e reprodutivas sobre Farlowella hahni em riachos da Bacia do rio Ivinhema, bacia do Alto Paraná. Um total de 165 indivíduos de F. hahni foi analisado, sendo 109 fêmeas e 48 machos. A proporção de sexo foi diferente de 1:1 (2=19,97; p 0,001), com predominância de fêmeas ao longo do ano. As fêmeas atingiram maior comprimento padrão do que os machos. Os machos apresentaram crescimento isométrico e as fêmeas crescimento alométrico positivo. O índice gonadossomático apresentou maiores valores de Outubro a Dezembro. A fecundidade média foi de 100,3±36,4 de ovócitos vitelogênicos e foi correlacionada positivamente com o comprimento padrão (r=0,51; p=0,01). Os dados apresentados são os primeiros para essa espécie e sugerem a necessidade de cuidados no manejo da população de F. hahni considerando baixa abundância e fecundidade.(AU)

Identification of genes associated with reproductive function in dairy cattle

The use of genomics has improved response to selection for functional traits with low heritability such as fertility traits. Much of the work on fertility traits has been performed through use of genome-wide association studies (GWAS) to identify genetic loci associated with reproductive traits. Under a GWAS approach, the assumption is that the markers on the panel are in linkage disequilibrium with causative mutations. In many cases, identification of the causative mutation is difficult because an associated genetic marker can be in intergenic regions and can be in linkage disequilibrium with variants in several nearby genes. Another approach is to identify candidate genes using knowledge of the biological pathways controlling a trait to search for single nucleotide polymorphism (SNP) in genes in those pathways. This should reveal putative causative markers responsible for genetic variation in biological function, and it is expected that the marker will be more strongly associated with a trait than one in linkage disequilibrium. An example of how a series of candidate gene studies demonstrate that identification of markers in genes involved in reproductive processes can lead to discovery of additional markers associated with genetic variation in reproductive traits is presented. In addition, the inclusion of candidate markers for fertility can improve reliability of genetic estimates for fertility traits, and the repeatability of the effects across a separate population of animals gives confidence that association elucidated by this set of markers is likely to be real. More importantly, the use of candidate genes can provide insights into the biology underpinning genetic variation in fertility, and that this understanding can lead to physiological interventions to improve reproductive function.

Identification of genes associated with reproductive function in dairy cattle

The use of genomics has improved response to selection for functional traits with low heritability such as fertility traits. Much of the work on fertility traits has been performed through use of genome-wide association studies (GWAS) to identify genetic loci associated with reproductive traits. Under a GWAS approach, the assumption is that the markers on the panel are in linkage disequilibrium with causative mutations. In many cases, identification of the causative mutation is difficult because an associated genetic marker can be in intergenic regions and can be in linkage disequilibrium with variants in several nearby genes. Another approach is to identify candidate genes using knowledge of the biological pathways controlling a trait to search for single nucleotide polymorphism (SNP) in genes in those pathways. This should reveal putative causative markers responsible for genetic variation in biological function, and it is expected that the marker will be more strongly associated with a trait than one in linkage disequilibrium. An example of how a series of candidate gene studies demonstrate that identification of markers in genes involved in reproductive processes can lead to discovery of additional markers associated with genetic variation in reproductive traits is presented. In addition, the inclusion of candidate markers for fertility can improve reliability of genetic estimates for fertility traits, and the repeatability of the effects across a separate population of animals gives confidence that association elucidated by this set of markers is likely to be real. More importantly, the use of candidate genes can provide insights into the biology underpinning genetic variation in fertility, and that this understanding can lead to physiological interventions to improve reproductive function.(AU)

Biometric testicular and serum testosterone concentration of Brazilian Ponies stallions / Biometria testicular e concentrações séricas de testosterona de garanhões Pôneis da raça Brasileira

Evaluation of the testis size is very important in stallions selection, since it is an indirect determinant of their reproductive potential. The aim of this study was to evaluate the biometric testicular traits, calculate the volume testicular and analyze the serum testosterone concentration of the stallion. During six months were measured the tests of adults Brazilian Ponies stallions from northern of Rio de Janeiro State, Brazil. The length, the width and the height of the testicles (TL, TW and TH) were measured. From these measurements, the total testicular volume (TTV) was calculated. The serum testosterone concentration was also evaluated. The data were studied by analysis of variance and were calculated the correlations among the traits. The average of the testis biometry were TL 5.8 ± 0.6 cm; TW 3.8 ± 0.5 cm; TH 4.7 ± 0.4 cm and 111.2 ± 27.7 for TTV. Mean of serum testosterone concentration was 0.89 ± 0.52 ng/dl. High correlations between biometry testicular traits with testicular volume were observed and low to moderate correlations were observed for testicular traits, testosterone and sperm output. The testis size could be an important trait that assists to the prediction of stallion's reproductive potential of the Brazilian ponies stallions. It is suggested that there would be no fluctuation in serum testosterone concentration in Brazilian ponies stallions that coult afect on its fertility.(AU)

Avaliação do tamanho dos testículos é muito importante na seleção de garanhões, uma vez que é um determinante indireto do seu potencial reprodutivo. O objetivo deste estudo foi avaliar as características de biometria testiculares, calcular o volume testicular e analisar a concentração sérica de testosterona de garanhões. Durante seis meses, foram medidos os testículos de garanhões Pôneis da raça Brasileiro adultos, criados no Norte do Estado do Rio de Janeiro, Brasil. O comprimento a largura e a altura dos testículo (TL, TW e TH) foram mensurados. A partir dessas medidas, calculou-se o volume testicular total (TTV). Os dados foram avaliados por análise de variância e foram calculadas as correlações entre as características. A média geral das características de biometria testicular e volume testicular foram: TL 5,8 ± 0,6 cm; TW 3,8 ± 0,5 cm; TH 4,7 ± 0,4 cm e TTV 111.2 ± 27,7. A média de concentração sérica de testosterona foi de 0,89 ± 0,52 ng/dl. Altas correlações foram observadas entre as características de biometria testicular e volume testicular. Baixas a médias correlações entre as características testiculares com produção espermática e com concentração de testosterona foram observadas. O tamanho testicular pode ser uma importante característica que auxilia na predição do potencial reprodutivo do garanhão pôneis da raça Brasileira. Sugere-se que não há variações na concentração sérica de testosterona nos pôneis da raça Brasileira que poderia afetar em sua fertilidade.(AU)

Biometric testicular and serum testosterone concentration of Brazilian Ponies stallions / Biometria testicular e concentrações séricas de testosterona de garanhões Pôneis da raça Brasileira

Evaluation of the testis size is very important in stallions’ selection, since it is an indirect determinant of their reproductive potential. The aim of this study was to evaluate the biometric testicular traits, calculate the volume testicular and analyze the serum testosterone concentration of the stallion. During six months were measured the tests of adults Brazilian Ponies stallions from northern of Rio de Janeiro State, Brazil. The length, the width and the height of the testicles (TL, TW and TH) were measured. From these measurements, the total testicular volume (TTV) was calculated. The serum testosterone concentration was also evaluated. The data were studied by analysis of variance and were calculated the correlations among the traits. The average of the testis biometry were TL 5.8 ± 0.6 cm; TW 3.8 ± 0.5 cm; TH 4.7 ± 0.4 cm and 111.2 ± 27.7 for TTV. Mean of serum testosterone concentration was 0.89 ± 0.52 ng/dl. High correlations between biometry testicular traits with testicular volume were observed and low to moderate correlations were observed for testicular traits, testosterone and sperm output. The testis size could be an important trait that assists to the prediction of stallion's reproductive potential of the Brazilian ponies stallions. It is suggested that there would be no fluctuation in serum testosterone concentration in Brazilian ponies stallions that coult afect on its fertility.

Avaliação do tamanho dos testículos é muito importante na seleção de garanhões, uma vez que é um determinante indireto do seu potencial reprodutivo. O objetivo deste estudo foi avaliar as características de biometria testiculares, calcular o volume testicular e analisar a concentração sérica de testosterona de garanhões. Durante seis meses, foram medidos os testículos de garanhões Pôneis da raça Brasileiro adultos, criados no Norte do Estado do Rio de Janeiro, Brasil. O comprimento a largura e a altura dos testículo (TL, TW e TH) foram mensurados. A partir dessas medidas, calculou-se o volume testicular total (TTV). Os dados foram avaliados por análise de variância e foram calculadas as correlações entre as características. A média geral das características de biometria testicular e volume testicular foram: TL 5,8 ± 0,6 cm; TW 3,8 ± 0,5 cm; TH 4,7 ± 0,4 cm e TTV 111.2 ± 27,7. A média de concentração sérica de testosterona foi de 0,89 ± 0,52 ng/dl. Altas correlações foram observadas entre as características de biometria testicular e volume testicular. Baixas a médias correlações entre as características testiculares com produção espermática e com concentração de testosterona foram observadas. O tamanho testicular pode ser uma importante característica que auxilia na predição do potencial reprodutivo do garanhão pôneis da raça Brasileira. Sugere-se que não há variações na concentração sérica de testosterona nos pôneis da raça Brasileira que poderia afetar em sua fertilidade.

Appropriate level of gilt fatness and muscularity during insemination can improve the efficiency of piglet production

The aim of this study was to determine the degree of fatness and muscularity of gilts with different genotypes on the basis of intravital measurements using an Aloka SSD-500 ultrasound scanner and defining the influence of these parameters on selected indicators of reproductive performance. Research was performed on 462 gilts maintained under the same production conditions. Gilts were divided into 3 groups according to genotype: 154 Landrace gilts (L), 154 Large White (LW), 154 Landrace × Large White – [L × LW]. Four selected reproductive indicators were analyzed: the number of piglets born alive (n), average piglet birth weight (kg), number of piglets weaned at 28 days (n) and the average weaned piglet weight (kg). Our results clearly show that an appropriate level of gilt fatness during insemination can contribute to significant improvements in the efficiency of piglet production. In order to increase the number of piglets born alive, the number of piglets at weaning and the masses in these periods, it is recommended insemination of L, LW and [L × LW] gilts when their backfat thickness behind the last rib 3 cm from the midline of the spine exceeds 25 mm. In the case of backfat thickness measured 8 cm from the midline of the spine, to improve the production efficiency of these gilts it is recommended to proceed to insemination, when the value of this trait exceeds 20 mm. In addition, insemination of gilts with the genotype [L × LW] should occur when the amount of LD muscle exceeds 60 mm, the width of the muscle is greater than 135 mm, and its surface is greater than 70 cm2 .