Repeatability of in vitro embryo production in Nellore breed / Repetibilidade na produção in vitro de embriões bovinos da raça Nelore

Recent advances in the field of animal assisted reproduction have allowed faster dissemination of animals with superior genetics. In cattle, the development of some biotechnologies such as the in vitro production (IVP) of embryos optimized the use of oocytes, which represents a great improvement in embryo production world-wide. Therefore, females with high net merit can be multiplied more efficiently to maximize the number of their offspring. The use of ultrasound-guided transvaginal follicle aspiration combined with IVP allowed wide commercial transfer of IVP-embryos with satisfactory pregnancy results. Yet, there are a number of unanswered areas including the level of repeatability and predictability in IVP systems. Thus, the aim of this study was to evaluate the repeatability of some variables related to IVP of bovine embryos from Nellore breed. The study was conducted from 2011 to 2012 using 42 Nellore cows housed at the Centro APTA Bovinos de Corte located in Sertãozinho-SP, Brazil. Donors were kept under the same management throughout the entire experimental period. All animals underwent a total of 25 transvaginal ultrasound-guided follicular aspiration sections. Oocytes were retrieved and handled similarly by Sexing Technologies using semen from 11 sires. Repeatability was evaluated in the following variables: total number of oocytes, embryos and viable oocytes, viable o

O artigo não possui resumo em português.

Effect of number of aspirations and months of the year on the total and viable oocytes in Nellore donors / Efeito do número de aspirações e meses do ano sobre a quantidade de oócitos totais e viáveis em doadoras Nelore

Several factors can influence the recovery of the amount of oocytes for in vitro embryo production (IVEP), including the age of the donor, the time and the frequency at which the animal is collected and climate station year. Another factor is the individual variation of each animal in the number of oocytes and embryos. Thus, the aim of this work was to evaluate the effect of the number of aspirations and the influence of the months of the year in the amount of total and viable oocytes in Nellore cows. The date was collected from January 2011 to December 2012. Non-lactating, cycling Nellore cows (n = 42) of high genetic value were used as oocyte donors. The procedures were carried out in a farm in southeast Brazil (21816S/48582W), located in humid tropical climate. All the donors were maintained on pasture consisting of guinea grass (Panicum maximum and Urochloa brizantha), getting protein mineral supplement energy and water ad libitum daily. The analyzes were performed by proc GLIMMIX of SAS 9.3 (SAS Inst., Inc., Cary, NC).  The amount of total oocytes (P=0.16) and viable (P=0.11) did not influenced by the number of aspirations. However, the months of the year have an effect on the amount of total and viable (P 0.0001) oocytes. Probably the production of oocytes did not suffer influences the number of aspirations performed mainly because the intervals between each OPU

O artigo não possui resumo em português.

Ultrasonographic evaluation of reproductive tract measures and fat thickness traits in pre-pubertal Nellore heifers / Avaliação ultrassonográfica do trato reprodutivo e espessura de gordura em novilhas Nelore pré-púberes

The aim of this study was to evaluate the relationship between reproductive tract and fat thickness measures obtained by ultrasound in prepubertal Nellore heifers. A total of 128 Nellore heifers born in 2006 and 2007 were submitted to ultrasound evaluations (13, 16, 19 and 22 months of age) of reproductive tract measures and fat thickness traits. These animals were from a selection experiment (NeC: control line, and NeS: selection line) for yearling weight started in 1981. Mean values of ovary area, height of the right uterine horn (HU), maximum follicular diameter (FOL), backfat thickness (BF), rump fat thickness (RF), and body condition score were analyzed. Repeated records were modeled using the PROC MIXED procedure (SAS), fitting a model that included the selection line, year of birth, measurement as fixed effects, and interactions. Body weight differed between the selected (281.48 kg) and control (210.51 kg) lines. Only the least square means of FOL were lower in the NeC line compared to the NeS line (P 0.05), although the difference in mean HU between the two lines was of only borderline significance (P = 0.06). The rate of growth for the three reproductive traits was similar in the two lines. Simple and residual correlations between the reproductive and subcutaneous fat traits ranged from low to medium. The highest correlations were observed between HU and RF (Pears

O objetivo deste estudo foi avaliar a relação entre medidas do trato reprodutivo com medidas de espessura de gordura subcutânea obtidas por ultrassom em novilhas Nelore. Um total de 128 novilhas Nelore, nascidas em 2006 e 2007, foi submetido a avaliações (13, 16, 19 e 22 meses de idade) ultrassonográficas do trato reprodutivo e da espessura de gordura subcutânea. Esses animais são provenientes de um experimento de seleção para peso ao sobreano (NeC: linha controle e NeS: linha selecionada) iniciada em 1981. As características analisadas foram: média da área dos ovários, altura do corno uterino direito , diâmetro do maior folículo (FOL), espessura de gordura no lombo (EGL), espessura de gordura na garupa (EGG), e escore de condição corporal. Os registros repetidos foram analisados usando o PROC MIXED (SAS), ajustando um modelo que incluiu os efeitos fixos de linha seleção, ano de nascimento, medida, e interações. O peso corporal diferiu entre as linhas seleção (281,48 kg) e controle (210,51 kg). Apenas as médias de FOL foram menores na linha NeC comparadas às da linha NeS (P 0,05), apesar da diferença próxima da significância de AU entre as duas linhas (P = 0,06). A taxa de crescimento das três características reprodutivas foi similar nas duas linhas. Correlações simples e de resíduo entre as características reprodutivas e as características relativas à gordura subcutân

Evaluation of sexual maturity of young bulls from different breeds selected for post-weaning weight / Avaliação andrológica de touros jovens de diferentes raças selecionados para peso pós-desmama

Sperm traits of 243 young bulls from Caracu (n=62), Gir (n=23), Guzerá (n=59) and Nellore (n=99) breeds, with 20-25 months of age, from the Breeding Program of Estação Experimental de Zootecnia de Sertãozinho, were analyzed. On the day of breeding soundness evaluation animals were weighed, the scrotal circumference was measured and the semen was collected by electroejaculation. The sperm motility, vigor and morphology were assessed and the animals were classified according to the andrological classification by points (CAP). No difference was observed among breeds for any seminal trait evaluated, although Nelore presented lower scrotal circumference average than the other breeds. When the animals were classified by body weight, it was observed that the heavier animals presented greater scrotal circumference, better seminal characteristics and, consequently, greater percentage of these animals were considered sexually mature comparing with the other body weight groups. It was concluded that the animals selected for post-weaning and reared on pasture from the taurine adapted breed Caracu and from the zebu breeds Gir, Guzerá and Nelore have proved able to reproduction at 23.2, 23.4, 22.7 and 22.8 months, respectively, corresponding to age which reached an average weight of 452, 422, 470 and 467 kg respectively.

Resumo: Foram submetidos a avaliação andrológica 243 touros jovens das raças Caracu (n=62), Gir (n=23), Guzerá (n=59) e Nelore (n=99), com idade entre 20 e 25 meses, participantes do Projeto de Seleção das Raças Zebuínas e Caracu, da Estação Experimental de Zootecnia de Sertãozinho. No dia da avaliação andrológica os animais foram pesados, o perímetro escrotal foi aferido e o sêmen foi coletado por meio de eletroejaculador. Foram avaliados motilidade, vigor e morfologia espermática e, posteriormente, os animais foram classificados segundo o sistema de classificação andrológica por pontos (CAP). Não foram observadas diferenças entre raças para as características seminais avaliadas, embora touros jovens Nelore tenham apresentado menor média de perímetro escrotal que as demais raças. Quando os animais foram classificados por classes de peso corporal, foi observado que os animais mais pesados apresentaram maior perímetro escrotal, melhores características seminais e, consequentemente, maior porcentagem deles foram considerados aptos a reprodução, comparativamente às demais classes de peso. Concluiu-se que os animais da raça taurina adaptada Caracu e das raças zebuínas Gir, Guzerá e Nelore, selecionados para peso pós-desmama e criados em pastagem, apresentaram-se aptos a reprodução aos 23,2, 23,4, 22,7 e 22,8 meses, respectivamente, correspondendo às idades em que atingiram peso méd

Classification of Nelore cattle frames based the table of the Beef Improvement Federation (BIF) / Classificação do tamanho de animais da raça Nelore com base na tabela da Federação Americana de Melhoramento de Gado de Corte (BIF)

Hip height records of yearling males and females (n=3.948), and from breeding cows (n=6.174) of Nelore breed, reared at the Estação Experimental de Zootecnia de Sertãozinho, Brazil, were used to study the viablility equations and tables published by Beef Improvement Federation (2006) viability to obtain frame scores. It was observed a high frequency of frames ranging from 6 to 7 for young animals and from 7 to 9 for cows, characterizing these animals as large, but not of extreme in size. However, the majority of the cows changed their frame with the age. Cow body weight, by frame score, was smaller than those cited in the literature for the European breeds. The female frame score repeatability estimates (0.76) and heritability (0.58) were high, however, they were smaller than hip height repeatability (0.84) and heritability (0.67) estimates.

Medidas de altura na garupa de animais Nelore, machos e fêmeas ao sobreano (n=3,948) e vacas em monta (n=6,174), pertencentes à Estação Experimental de Zootecnia de Sertãozinho, foram usadas para estudar a viabilidade do uso das equações e tabelas publicadas no Beef Improvement Federation (2006) para obtenção do escore de frame. Foi observada alta freqüência de frame entre 6 e 7 nos animais jovens e entre 7 e 9 nas vacas, caracterizando-os como de grande porte, mas não extremo. Entretanto, a maioria das vacas teve o escore de frame alterado conforme a idade. As vacas da raça Nelore apresentaram peso corporal, por escore de frame, menor que os pesos citados na literatura para as raças européias. As estimativas de repetibilidade (0,76) e herdabilidade (0,58) do escore de frame das fêmeas foram altas, entretanto menores que as estimadas para a altura (0,67 e 0,84, respectivamente).

Classification of Nelore cattle frames based the table of the Beef Improvement Federation (BIF) / Classificação do tamanho de animais da raça Nelore com base na tabela da Federação Americana de Melhoramento de Gado de Corte (BIF)

Hip height records of yearling males and females (n=3.948), and from breeding cows (n=6.174) of Nelore breed, reared at the Estação Experimental de Zootecnia de Sertãozinho, Brazil, were used to study the viablility equations and tables published by Beef Improvement Federation (2006) viability to obtain frame scores. It was observed a high frequency of frames ranging from 6 to 7 for young animals and from 7 to 9 for cows, characterizing these animals as large, but not of extreme in size. However, the majority of the cows changed their frame with the age. Cow body weight, by frame score, was smaller than those cited in the literature for the European breeds. The female frame score repeatability estimates (0.76) and heritability (0.58) were high, however, they were smaller than hip height repeatability (0.84) and heritability (0.67) estimates.

Medidas de altura na garupa de animais Nelore, machos e fêmeas ao sobreano (n=3,948) e vacas em monta (n=6,174), pertencentes à Estação Experimental de Zootecnia de Sertãozinho, foram usadas para estudar a viabilidade do uso das equações e tabelas publicadas no Beef Improvement Federation (2006) para obtenção do escore de frame. Foi observada alta freqüência de frame entre 6 e 7 nos animais jovens e entre 7 e 9 nas vacas, caracterizando-os como de grande porte, mas não extremo. Entretanto, a maioria das vacas teve o escore de frame alterado conforme a idade. As vacas da raça Nelore apresentaram peso corporal, por escore de frame, menor que os pesos citados na literatura para as raças européias. As estimativas de repetibilidade (0,76) e herdabilidade (0,58) do escore de frame das fêmeas foram altas, entretanto menores que as estimadas para a altura (0,67 e 0,84, respectivamente).

Evaluation of sexual maturity of young bulls from different breeds selected for post-weaning weight / Avaliação andrológica de touros jovens de diferentes raças selecionados para peso pós-desmama

Sperm traits of 243 young bulls from Caracu (n=62), Gir (n=23), Guzerá (n=59) and Nellore (n=99) breeds, with 20-25 months of age, from the Breeding Program of Estação Experimental de Zootecnia de Sertãozinho, were analyzed. On the day of breeding soundness evaluation animals were weighed, the scrotal circumference was measured and the semen was collected by electroejaculation. The sperm motility, vigor and morphology were assessed and the animals were classified according to the andrological classification by points (CAP). No difference was observed among breeds for any seminal trait evaluated, although Nelore presented lower scrotal circumference average than the other breeds. When the animals were classified by body weight, it was observed that the heavier animals presented greater scrotal circumference, better seminal characteristics and, consequently, greater percentage of these animals were considered sexually mature comparing with the other body weight groups. It was concluded that the animals selected for post-weaning and reared on pasture from the taurine adapted breed Caracu and from the zebu breeds Gir, Guzerá and Nelore have proved able to reproduction at 23.2, 23.4, 22.7 and 22.8 months, respectively, corresponding to age which reached an average weight of 452, 422, 470 and 467 kg respectively.

Resumo: Foram submetidos a avaliação andrológica 243 touros jovens das raças Caracu (n=62), Gir (n=23), Guzerá (n=59) e Nelore (n=99), com idade entre 20 e 25 meses, participantes do Projeto de Seleção das Raças Zebuínas e Caracu, da Estação Experimental de Zootecnia de Sertãozinho. No dia da avaliação andrológica os animais foram pesados, o perímetro escrotal foi aferido e o sêmen foi coletado por meio de eletroejaculador. Foram avaliados motilidade, vigor e morfologia espermática e, posteriormente, os animais foram classificados segundo o sistema de classificação andrológica por pontos (CAP). Não foram observadas diferenças entre raças para as características seminais avaliadas, embora touros jovens Nelore tenham apresentado menor média de perímetro escrotal que as demais raças. Quando os animais foram classificados por classes de peso corporal, foi observado que os animais mais pesados apresentaram maior perímetro escrotal, melhores características seminais e, consequentemente, maior porcentagem deles foram considerados aptos a reprodução, comparativamente às demais classes de peso. Concluiu-se que os animais da raça taurina adaptada Caracu e das raças zebuínas Gir, Guzerá e Nelore, selecionados para peso pós-desmama e criados em pastagem, apresentaram-se aptos a reprodução aos 23,2, 23,4, 22,7 e 22,8 meses, respectivamente, correspondendo às idades em que atingiram peso méd

Ultrasonographic evaluation of reproductive tract measures and fat thickness traits in pre-pubertal Nellore heifers / Avaliação ultrassonográfica do trato reprodutivo e espessura de gordura em novilhas Nelore pré-púberes

The aim of this study was to evaluate the relationship between reproductive tract and fat thickness measures obtained by ultrasound in prepubertal Nellore heifers. A total of 128 Nellore heifers born in 2006 and 2007 were submitted to ultrasound evaluations (13, 16, 19 and 22 months of age) of reproductive tract measures and fat thickness traits. These animals were from a selection experiment (NeC: control line, and NeS: selection line) for yearling weight started in 1981. Mean values of ovary area, height of the right uterine horn (HU), maximum follicular diameter (FOL), backfat thickness (BF), rump fat thickness (RF), and body condition score were analyzed. Repeated records were modeled using the PROC MIXED procedure (SAS), fitting a model that included the selection line, year of birth, measurement as fixed effects, and interactions. Body weight differed between the selected (281.48 kg) and control (210.51 kg) lines. Only the least square means of FOL were lower in the NeC line compared to the NeS line (P 0.05), although the difference in mean HU between the two lines was of only borderline significance (P = 0.06). The rate of growth for the three reproductive traits was similar in the two lines. Simple and residual correlations between the reproductive and subcutaneous fat traits ranged from low to medium. The highest correlations were observed between HU and RF (Pears

O objetivo deste estudo foi avaliar a relação entre medidas do trato reprodutivo com medidas de espessura de gordura subcutânea obtidas por ultrassom em novilhas Nelore. Um total de 128 novilhas Nelore, nascidas em 2006 e 2007, foi submetido a avaliações (13, 16, 19 e 22 meses de idade) ultrassonográficas do trato reprodutivo e da espessura de gordura subcutânea. Esses animais são provenientes de um experimento de seleção para peso ao sobreano (NeC: linha controle e NeS: linha selecionada) iniciada em 1981. As características analisadas foram: média da área dos ovários, altura do corno uterino direito (AU), diâmetro do maior folículo (FOL), espessura de gordura no lombo (EGL), espessura de gordura na garupa (EGG), e escore de condição corporal. Os registros repetidos foram analisados usando o PROC MIXED (SAS), ajustando um modelo que incluiu os efeitos fixos de linha seleção, ano de nascimento, medida, e interações. O peso corporal diferiu entre as linhas seleção (281,48 kg) e controle (210,51 kg). Apenas as médias de FOL foram menores na linha NeC comparadas às da linha NeS (P 0,05), apesar da diferença próxima da significância de AU entre as duas linhas (P = 0,06). A taxa de crescimento das três características reprodutivas foi similar nas duas linhas. Correlações simples e de resíduo entre as características reprodutivas e as características relativas à gordura subcutân

Effects of fatty acid suplementation in Holstein cows at pre and post partum period, on estrous cycle return and in vitro production of embryos / Efeitos da suplementação com fontes de ácidos graxos em doadoras da raça Holandesa durante o pré e pós-parto sobre o retorno à ciclicidade e produção in vitro de embriões

The supplementation of dairy cattle with sources of polyunsaturated fatty acids (PUFA) can be use to increase the energy level of the diet in addition to having positive effects on reproductive functions of important tissues including the hypothalamus, pituitary, ovaries and uterus. The aims of this study were to evaluate the reproductive conditions of the postpartum, number of follicles, corpus luteum (CL) presence, concentration of progesterone (P4), aspirated oocytes, amount of viable oocytes and in vitro production of embryos (IVPE) of the Holstein multiparous donors supplemented with rich diet in protected PUFA (especially linoleic acid - n- 6) and non-protected (especially linolenic acid - n-3) during pre and post partum. The diets had been given for pre-partum during 30 d and post partum 60 d. The donors were divided into three groups: Control (n=6), Megalac-E® (n=5; supplemented with protected fat source 100 g/donor/ day in pre-partum and 300 g/donor/day in postpartum) and linseed (n=5; supplemented with fat source unprotected containing 1 kg/donor/day pre-partum and 1.5 kg/donor/day in postpartum). The animals were submitted to ovum pick-up (OPU) on days 30, 45 and 60 d postpartum. The recovered oocytes were selected and the viable ones were submitted to IVPE procedures. The data were analyzed by the method of least squares variance using the GLM protocol. The differen

A suplementação de bovinos leiteiros com fontes de ácidos graxos poliinsaturados (AGPs) é uma prática utilizada para aumentar o nível energético das dietas, além de proporcionar efeitos positivos nas funções reprodutivas de importantes tecidos, incluindo hipotálamo, hipófise, ovários e útero. O trabalho foi conduzido com objetivo de avaliar as condições reprodutivas do pós-parto, número de folículos, presença de corpo lúteo (CL), concentração de progesterona (P4), quantidade de oócitos viáveis e totais e a produção in vitro de embriões (PIVE) de doadoras multíparas da raça Holandesa suplementadas com dieta rica em AGPs protegido (principalmente ácido linoleico - n-6) e não protegido (principalmente ácido linolênico - n-3) durante o pré e pósparto. As dietas foram fornecidas por 30 dias pré-parto e 60 dias pós-parto. As doadoras foram divididas aleatoriamente em 3 grupos: Controle (n=6), Megalac-E® (n=5; suplementados com fonte de gordura protegida 100 g/doadora/dia no pré-parto e 300 g/doadora/dia no pós-parto) e linhaça (n=5); fonte de gordura não protegida contendo 1 kg/doadora/dia no pré-parto e 1,5 kg/ doadora/dia no pós-parto). Os animais foram submetidos à aspiração folicular (OPU) nos dias 30, 45 e 60 pós-parto. Os oócitos recuperados foram selecionados e os viáveis submetidos aos procedimentos da PIVE. Os dados foram analisados pelo método dos quadrados mínimos utilizan

Effect of number of aspirations and months of the year on the total and viable oocytes in Nellore donors / Efeito do número de aspirações e meses do ano sobre a quantidade de oócitos totais e viáveis em doadoras Nelore

Several factors can influence the recovery of the amount of oocytes for in vitro embryo production (IVEP), including the age of the donor, the time and the frequency at which the animal is collected and climate station year. Another factor is the individual variation of each animal in the number of oocytes and embryos. Thus, the aim of this work was to evaluate the effect of the number of aspirations and the influence of the months of the year in the amount of total and viable oocytes in Nellore cows. The date was collected from January 2011 to December 2012. Non-lactating, cycling Nellore cows (n = 42) of high genetic value were used as oocyte donors. The procedures were carried out in a farm in southeast Brazil (21816S/48582W), located in humid tropical climate. All the donors were maintained on pasture consisting of guinea grass (Panicum maximum and Urochloa brizantha), getting protein mineral supplement energy and water ad libitum daily. The analyzes were performed by proc GLIMMIX of SAS 9.3 (SAS Inst., Inc., Cary, NC).  The amount of total oocytes (P=0.16) and viable (P=0.11) did not influenced by the number of aspirations. However, the months of the year have an effect on the amount of total and viable (P 0.0001) oocytes. Probably the production of oocytes did not suffer influences the number of aspirations performed mainly because the intervals between each OPU

O artigo não possui resumo em português.

Repeatability of in vitro embryo production in Nellore breed / Repetibilidade na produção in vitro de embriões bovinos da raça Nelore

Recent advances in the field of animal assisted reproduction have allowed faster dissemination of animals with superior genetics. In cattle, the development of some biotechnologies such as the in vitro production (IVP) of embryos optimized the use of oocytes, which represents a great improvement in embryo production world-wide. Therefore, females with high net merit can be multiplied more efficiently to maximize the number of their offspring. The use of ultrasound-guided transvaginal follicle aspiration combined with IVP allowed wide commercial transfer of IVP-embryos with satisfactory pregnancy results. Yet, there are a number of unanswered areas including the level of repeatability and predictability in IVP systems. Thus, the aim of this study was to evaluate the repeatability of some variables related to IVP of bovine embryos from Nellore breed. The study was conducted from 2011 to 2012 using 42 Nellore cows housed at the Centro APTA Bovinos de Corte located in Sertãozinho-SP, Brazil. Donors were kept under the same management throughout the entire experimental period. All animals underwent a total of 25 transvaginal ultrasound-guided follicular aspiration sections. Oocytes were retrieved and handled similarly by Sexing Technologies using semen from 11 sires. Repeatability was evaluated in the following variables: total number of oocytes, embryos and viable oocytes, viable o

O artigo não possui resumo em português.