Manifestation of estrous behavior and subsequent progesterone concentration at timed-embryo transfer in cattle are positively associated with pregnancy success of recipients

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos da suplementação com semente de girassol em fêmeas bovinas na produção de oócitos e embriões in vitro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desempenho e qualidade da carne de bovinos cruzados alimentados com diferentes dietas em confinamento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Seleção e associação genômica para precocidade sexual em bovinos da raça Nelore

Pós-graduação em Genética e Melhoramento Animal - FCAV

Avaliação do desempenho e características relacionadas ao grau de infecção por helmintos de bovinos da raça nelore

Pós-graduação em Ciência e Tecnologia Animal - FEIS

Efeito da progesterona na expressão do RNAm do receptor de LH e enzimas esteroidogênicas reguladoras do desenvolvimento folicular em células da granulosa de novilhas nelore

Pós-graduação em Zootecnia - FMVZ

Suplementação com levedura de Crômio eleva a concentração sérica de Crômio em bovinos

This study evaluated the effect of daily chromium supplementation at growing doses on serum Cr levels in cattle. Sixty Nellore heifers 2 to 5 years old were randomly assigned to one of four groups (15 heifers/group) fed non-fertilized Brachiaria decumbens pasture. In the control group (Gc), the heifers received a mineral mixture without Cr. In the other groups, heifers received 0.59, 1.19 or 2.38 mg Cr+3/animal/day, groups G8,5, G17 and G34, respectively. Blood samples were collected on days 0, 30 and 60. Serum concentration of chromium was determined by graphite furnace atomic absorption spectrophotometer. The chromium source used was the chromium yeast. The results do not support any significant difference (p>0.05) among serum chromium levels of heifers in groups Gc, G8,5, G17 and G34 at a same observation day. Only effect of supplementation time was detected in group G34. In this group there was significant increase (p<0,05) in the concentration serum chromium 60 days after the beginning of the experiment. Concluded Cr yeast can be used as the source of this mineral element for animals and supplementation with 2.38 mg/ cattle/day was the dose that most increased the serum concentration of Cr in Nellore cattle during the experimental period.

Estudo do nível de infecção por Babesia bovis e Babesia bigemina em bovinos da raça Canchim naturalmente infestados com o carrapato Rhipicephalus (Boophilus) microplus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo de associação genômica e perfil de expressão gênica de folículos antrais em novilhas das raças nelore e angus, associadas ao fenótipo de alta e baixa população folicular

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estimativas de parâmetros genéticos e fenotípicos para características reprodutivas e de temperamento em bovinos da raça Nelore

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

RB30-252 Sex and Age as Factors in Cattle Feeding

Varying economic conditions and changes in the demands of the meat consuming public have been responsible for the turns that have taken place in the beef industry during recent years. Both feeder and producer must recognize and conform to these changes if they are to continue in business. Among the most important of these changes have been the turn toward the marketing of lighter cattle and the gradual disappearance from feed lots of two- and three-year-old animals. Furthermore, the cattle population of the United States is fast reaching stabilization with the resulting effect that more heifers are being marketed, since only one-fourth of the heifer crop is needed to replace worn-out breeding animals. Realizing the increasing importance of the heifer problem from the standpoint of the producer, feeder, and consumer, the Nebraska Experiment Station undertook to compare steers and heifers in a series of trials both in the feedlot and in the beef. It was hoped that these experiments would yield results which would bring out existing differences, if any, between steers and heifers both in quality and quantity of beef produced and thus provide or disprove many of the complaints against heifers. The results of these trials are summarized in this bulletin. Age as well as the sex factor has been considered, since two-year-olds, yearlings, and calves were included in these trials.

Estimativas de parâmetros genéticos e fenotípicos para características reprodutivas e de temperamento em bovinos da raça Nelore

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of two estradiol esters (benzoate and cypionate) on the induction of synchronized ovulations in Bos indicus cows submitted to a timed artificial insemination protocol

The effects of estradiol benzoate (EB) and estradiol cypionate (EC) on induction of ovulation after a synchronized LH surge and on fertility of Bos indicus females submitted to timed AI (TAI) were evaluated. In Experiment 1, ovariectomized Nelore heifers were used to evaluate the effect of EB (n = 5) and EC (n = 5) on the circulating LH profile. The LH surge timing (19.6 and 50.5 h; P = 0.001), magnitude (20.5 and 9.4 ng/mL; P = 0.005), duration (8.6 and 16.5 h; P = 0.001), and area under the LH curve (158.6 and 339.4 ng/mL; P = 0.01) differed between the EB and EC treatments, respectively. In Experiment 2 (follicular responses; n = 60) and 3 (pregnancy per AI; P/AI; n = 953) suckled Bos indicus beef cows submitted to an estradiol/progesterone-based synchronization protocol were assigned to receive one of two treatments to induce synchronized ovulation: 1 mg of EB im 24 h after progesterone (P4) device removal or 1 mg of EC im at P4 device removal. There was no difference (P > 0.05) between EB and EC treatments on follicular responses (maximum diameter of the ovulatory follicle, 13.1 vs. 13.9 mm; interval from progesterone device removal to ovulation, 70.2 vs. 68.5 h; and ovulation rate, 77.8 vs. 82.8%, respectively). In addition, P/AI was similar (P < 0.22) between the cows treated with EB (57.5%; 277/482) and EC (61.8%; 291/471). In conclusion, despite pharmacologic differences, both esters of estradiol administered either at P4 device removal (EC) or 24 h later (EB) were effective in inducing an LH surge which resulted in synchronized ovulations and similar P/AI in suckled Bos indicus beef cows submitted to TAI. (C) 2012 Elsevier Inc. All rights reserved.

Expressão do gene da leptina e seu receptor Ob-Rb no parênquima mamário de novilhas leiteiras

Objetivou-se com este trabalho avaliar os efeitos de uma dieta de alto nível de energia e proteína combinada com a aplicação de bST no perfil de expressão dos genes da leptina e de seu receptor Ob-Rb no parênquima mamário de novilhas leiteiras. Foram utilizadas amostras de parênquima mamário de 32 novilhas holandesas distribuídas aleatoriamente em quatro tratamentos (n=8): dieta com alto ou baixo teor de energia e proteína combinada ou não com a aplicação de bST. O delineamento utilizado foi em blocos casualizados com arranjo de tratamentos em esquema fatorial 2 × 2. A extração do RNA total das amostras de tecido foi feita e o nível de expressão gênica foi analisado por qRT-PCR utilizando-se o gene da glicuronidase β como controle, pelo método 2-ΔΔCt. Animais que receberam a dieta com alto conteúdo de energia e proteína apresentaram maior expressão de mRNA de leptina, com aumento de 56%, e menor expressão de mRNA do receptor Ob-Rb, com redução de 18%. Por outro lado, a aplicação de bST resultou em diminuição da expressão do mRNA de leptina e do receptor Ob-Rb em 74% e 23%, respectivamente. Não houve interação entre dieta e aplicação de bST. O aumento na expressão de leptina pode explicar, ao menos em parte, os efeitos negativos da dieta de alta energia e proteína, oferecida no período pré-púbere, sobre a produção de leite de novilhas leiteiras.

Effect of nAellore cows ciclicity on conception and pregnant rates after synchronization protocols for fixed timed artificial insemination

Palhano H.B., Jesus V.L.T., Abidu-Figueiredo M., Baldrighi J.M. & Mello M.R.B. [Effect of nAellore cows ciclicity on conception and pregnant rates after synchronization protocols for fixed timed artificial insemination]. Efeito da ciclicidade de vacas Nelore sobre as taxas de concepcao e de prenhez apos protocolos de sincronizacao para inseminacao artificial em tempo fixo. Revista Brasileira de Medicina Veterinaria, 34(1):63-68, 2012. Departamento de Biologia Animal, Universidade Federal Rural do Rio de Janeiro, BR 465 km 7, Seropedica, RJ 23890-000, Brasil. Email: hbpalhano@gmail.com The present study evaluated the effect on conception and pregnancy rates of Nellore cows selected for Fixed Timed Artificial Insemination (FTAI) program, submitted to four synchronization protocols. Four hundred and ninety lactating females were used and assigned to eight groups: I-OvSynch, n=68, with selection of cycling cows; II-OvSynch + progesterone (P-4), n=67, after selection of non-cycling animals; III-OvSynch, without selection, n=68; IV-OvSynch + P-4, without selection, n=67; V-Co-Synch, n=55, with selection of cycling cows; VI-Co-Synch + P-4, n=55, with selection non-cycling cows; VII- Co-Synch without selection, n=55; VIII- Co-Synch + P-4, without selection, n=55. The conception and pregnancy rates were, respectively, 45.6%, 27.9% and 82.4%, 48.5% for groups I and III; 61.2%, 37.3% and 85.1%, 58.2% for groups II and IV; 43.6%, 25.5% and 80%, 41.8% for groups V and VII; 52.7%, 32.7% and 83.6%, 50.9% for groups VI and VIII. When compared these rates, the results after chi-square test showed significant difference (P < 0.05) among protocols with or without selection. There was no significant difference (P > 0.05) between OvSynch and Co-Synch protocols, with or without P-4 and with selection, considering Co-Synch a viable option for optimization of FTAI. In conclusion, the selection of cows before FTAI program contributed significantly to improve the conception and pregnancy rates.