Relationship of residual feed intake with semen parameters and testicular ultrasound of Nellore bulls

The objective of this study was to evaluate characteristics of the testicular parenchyma and vascular parameters of the pampiniform plexus obtained by ultrasound, semen quality parameters, and sperm freezability in Nellore bulls classified based on residual feed intake (RFI). Twenty-seven bulls (21.82±0.88 months of age) evaluated for feed efficiency were sampled for the study, including 15 with low RFI (−0.592±0.09 kg dry matter/day) and 12 with high RFI (0.792±0.10 kg dry matter/day). In ultrasound and Doppler assessment, the most efficient animals (low RFI) showed higher pulsatility and resistive indexes, as well as a tendency towards greater heterogeneity of the testicular parenchyma (0.625±0.032 vs. 0.508±0.032, 1.012±0.072 vs. 0.802±0.072, and 12.9±0.96 vs. 10.2±0.96, respectively, for low vs. high RFI). However, these animals tended to have lower peak diastolic velocity (5.19±0.50 for low RFI vs. 6.54±0.50 for high RFI). Analysis of fresh semen showed a lower percentage of minor defects in low RFI animals (2.67±1.19%) compared with high RFI animals (8.10±1.19%), without differences in the other parameters in fresh or thawed semen and after thermoresistance testing. Evaluation of flow cytometry parameters showed a higher quality of mitochondrial respiration in semen samples of low RFI animals (22.04±2.50%) compared with high RFI animals (12.29±2.71%). Therefore, although RFI exerts an effect on the Doppler parameters of the pampiniform plexus, it is not sufficient to affect the quality of fresh or thawed semen.(AU)

Growth performance, reproductive parameters and fertility measures in young Nellore bulls with divergent feed efficiency

The growth, sexual maturity and fertility-related parameters related of young Nellore bulls with divergent residual feed intake (RFI) raised on pasture were evaluated. After classification of 48 young males as low and high RFI (more and less efficient, respectively), the animals were evaluated for growth and reproductive parameters at 28-day intervals from 14.3 to 24.6 months of age. The semen was cryopreserved in the last sampling and fresh and post-thaw semen samples were evaluated. Low RFI bulls exhibited higher initial and final body weight (P < 0.05), but feed intake, body condition score and growth measures evaluated by carcass ultrasound were unaffected by RFI (P > 0.05). The scrotal circumference, sperm concentration, defects, and quality of fresh semen, and ultrasonographic testicular characteristics were unaffected by RFI (P > 0.05). However, velocity parameters such as average path and curvilinear velocities determined by computer-assisted sperm analysis of thawed semen submitted to the rapid thermoresistance test were improved (P < 0.05) in low RFI bulls, but this improvement in quality did not enhance in vitro sperm fertilizing ability. Our results demonstrated significant differences in metabolism and growth performance between bulls of divergent RFI. In addition, there was slight improvement in the semen quality of bulls with low RFI bulls, but this did not enhance in vitro fertilizing ability. Selection of beef bulls for RFI can be performed, which will result in economic benefits by improving the growth performance of the animals without affecting reproductive parameters.(AU)

Conception rate of lactating cows and heifers (Bos taurus X Bos indicus) for sexed and conventional semen in artificial insemination / Taxa de concepção de vacas lactantes e novilhas (Bos taurus X Bos indicus) com o uso de sêmen sexado e convencional na inseminação artificial

The objective of this study was to evaluate the conception rate of crossbred heifers (n=50) and cows (n=50) inseminated with sexed and conventional semen between 18 and 24 hours after estrous detection. The synchronization protocol of the estrous cycle started on day zero (D0) by inserting the intravaginal device with 1g progesterone (Sincrogest® Ourofino, Brazil) and injecting 2 mg of estradiol benzoate, intramuscularly (Sincrodiol® Ourofino, Brazil). On the fifth day (D5), 200 IU of equine chorionic gonadotrophin was injected intramuscularly (Folligon®, Intervet, Brazil). On the eighth day (D8), after removing the progesterone device, 500 g of sodium cloprostenol was injected intramuscularly (Sincrocio®, Ourofino, Brazil). After that, the animals were checked for estrus 3 times daily, and inseminated 18 to 24 hours after estrus detection. Pregnancy diagnosis was performed 30 to 40 days after insemination. Conception rate did not differ (P> 0.05) according to animal category, but was higher for conventional semen compared to sexed semen when evaluating the total of animals and lactating cows (P < 0.05). Artificial insemination of heifers with sexed semen 18 to 24 hours after estrus detection was effective, however, conventional semen was more efficient in lactating cows.(AU)

Considerando os benefícios do uso de sêmen sexado e também os danos causados pelo processo de separação dos espermatozoides, o objetivo do presente estudo foi avaliar a taxa de concepção de novilhas (n=50) e vacas (n=50) mestiças inseminadas com sêmen sexado e convencional após 18 a 24 horas a observação do cio. O protocolo de sincronização do ciclo estral consistiu em inserção de dispositivo intravaginal com 1g de progesterona (Sincrogest® Ourofino, Brasil) e aplicação intramuscular de 2mg de benzoato de estradiol (Sincrodiol® Ourofino, Brasil) no dia zero (D0). No quinto dia (D5), foi realizada uma aplicação intramuscular de 200UI de gonadotrofina coriônica equina (Folligon®, Intervet, Brasil). No oitavo dia (D8), o dispositivo de progesterona foi retirado, e aplicado por via intramuscular 500g de cloprostenol sódico (Sincrocio®, Ourofino, Brasil). A partir deste momento, o estro foi observado 3 vezes ao dia e os animais foram inseminados 18 a 24 após a detecção do cio. O diagnóstico de gestação foi realizado 30 a 40 dias após a inseminação. Não foi observada diferença na taxa de concepção de acordo com a categoria animal (P > 0,05), entretanto, animais inseminados com sêmen convencional apresentaram melhor taxa de concepção do que com sêmen sexado quando se avaliou o total de animais e vacas lactantes (P < 0,05). A inseminação artificial de novilhas com sêmen sexado 18 a 24 horas após detecção de estro mostrou-se eficaz, entretanto, para vacas lactantes não foi observada a mesma eficiência ao se comparar com o sêmen convencional.(AU)

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 / Effects of fatty acid supplementation in Holstein cows at pre and postpartum period, on estrous cycle return and in vitro production of embryos

A suplementação de bovinos leiteiros com fontes de ácidos graxos poli-insaturados (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 (P), 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 pós-parto. 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 utilizando análise de variância pelo procedimento GLM. As diferenças entre as médias foram comparadas pelo teste de Tukey com significância de 5%. Não foi detectado efeito de tratamento de suplementação, de dias de aspirações pós-parto e das interações sobre as variáveis: quantidade de oócitos viáveis, taxa de oócitos viáveis, número de clivagem, de PIVE, taxa de doadoras com CL concentração de P. (P>0,05). No entanto, foi observado maior número de folículos e de oócitos totais no grupo suplementado com linhaça em relação ao grupo Megalac-E® e Controle (P<0,05). A suplementação com AGPs não aumentou o número de oócitos viáveis, a PIVE e o retorno à ciclicidade.

The supplementation of dairy cattle with sources of polyunsaturated fatty acids (PUFA) can be used 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 postpartum. The diets had been given for pre-partum during 30 d and postpartum 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 differences between averages were compared by Tukey test with 5% significance. There was no detectable effect of treatment, aspirations of postpartum days and interactions on variables: CL presence, concentration of P4, amount of viable oocytes, viable oocytes rate, IVPE and embryos production rate. However, was observed in the group supplemented with linseed more follicles and total oocytes than Megalac-E® and Control group. Supplementation with PUFA didn't increase the number of viable oocytes and IVPE.

Efeitos da suplementação com fontes de ácidos graxos em doadoras das raças holandesa e nelore durante o pré e pós-parto, sobre o retorno à ciclicidade e produção in vitro de embriões

As suplementações de bovinos com fontes de ácidos graxos poliisaturados (AGPs) são formas de aumentar o nível energético das dietas, além de possuir efeito na reprodução dos ruminantes. Tendo em vista o exposto idealizouse o presente trabalho com o objetivo de avaliar as condições reprodutivas do pósparto, número de folículos, quantidade de oócitos totais, de viáveis e a PIVE de doadoras primíparas da raça Nelore (Experimento 1) e multíparas da raça Holandesa (Experimento 2) suplementadas com dieta rica em AGPs protegido (Megalac-E®, principalmente de n-6) e não protegido (Linhaça, principalmente de n- 3) durante o pré e pós-parto. No experimeto 1 as doadoras Nelore foram divididas aleatoriamente em 3 grupos, sendo que o grupo controle apresentou 7 fêmeas, o segundo grupo, com 8 animais que foram suplementados com uma fonte de gordura protegida contendo 100g/doadora/dia de Megalac-E® e o terceiro grupo com 7 fêmeas suplementadas com uma fonte de gordura não protegida contendo 1kg/doadora/dia de torta de linhaça. As dietas foram fornecidas por 30 dias pré-parto e 75 dias pós-parto. Estes animais foram submetidos à OPU nos dias 30, 45, 60 e 75 pós-parto. No experimento 2 as doadoras Holandesa foram divididas aleatoriamente em 3 grupos, sendo que o grupo controle apresentava 6 fêmeas, o segundo grupo, com 5 animais que foram suplementados com uma fonte de gordura protegida contendo 100g/doadora/dia de Megalac-E® no pré-parto e 300g/doadora/dia no pós-parto e o terceiro grupo com 5 fêmeas suplementadas com uma fonte de gordura não protegida contendo 1kg/doadora/dia de torta de linhaça no pré-parto e 1,5kg/doadora/dia no pós-parto. As dietas foram fornecidas por 30 dias pré-parto e 60 dias pós-parto. Estes animais foram submetidos à OPU nos dias 30, 45 e 60 pós-parto...

The supplementation of cattle with sources of polyunsaturated fatty acids (PUFA) are ways to increase the energy level of the diet, in addition to having effect on reproduction. The aim of this study were to evaluate the reproductive conditions of the postpartum, number of follicles, aspirates oocytes, amount of viable oocytes and the IVPE of the Nelore primiparous donors (Experiment 1) and Holstein multiparous donors (Experiment 2) supplemented with rich diet in protected PUFA (Megalac-E®) and non-protected (Linseed) during pre and postpartum. In experiment 1 Nelore donors were divided into three groups, the control group with 7 animals, the second group, with 8 animals were supplemented with a source of protected fat contains 100g/donor/day of Megalac-E® and the third group with 7 animals supplemented with a source of unprotected fat contains 1kg/donor/day linseed. The diets were fed for antepartum thirty days and postpartum seventy-five days. These animals were submitted to OPU on days 30, 45, 60 and 75 postpartum. In Experiment 2 Holstein donors were divided into three groups, the control group with 6 animals the second group, with 5 animals were supplemented with a source of protected fat contains 100g/donor/day of Megalac-E® in pre-partum and 300g/donor/day in postpartum and the third group with 5 animals supplemented with a source of fat unprotected contains 1kg/donor/day linseed pre-partum and 1.5 kg/donor/day in postpartum. The diets were fed for antepartum thirty days and postpartum sixty days. These animals were submitted to OPU on days 30, 45 and 60 postpartum. The recovered oocytes from both experiments were selected and the viable oocytes were submitted to procedures of the IVPE. The data from both experiments were analyzed by the method of least squares using variance analysis...