Browsing by Author "Silva, Joaquim Fernando Moreira da"
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- Association between Plasma and Milk Urea on the Insemination Day and Pregnancy Rate in Early Lactation Dairy CowsPublication . Chaveiro, António E.; Andrade, M.; Borba, Alfredo Emílio Silveira de; Silva, Joaquim Fernando Moreira daLactatingdairy cows (n=177) feed with grass and corn silage ad libitum kept in pasture, were randomly assigned to evaluate how urea nitrogen in plasma and milk can be related to their pregnancy rate. Blood and milk samples were collected on the artificial insemination (AI) day to evaluate plasma urea nitrogen (PUN) and milk urea nitrogen (MUN) as well as progesterone levels, excluding cows with progesterone higher than 0.5 ng/ml. Cows were considered pregnant if six weeks after artificial insemination, they did not return to estrus.Concentrations of PUN or MUN greater than the average (16 mg/dl) were associated with decreased pregnancy rates (13% and 14%, respectively) (p< 0.05) as compared to the cows with urea levels less than this value on the insemination day. As PUN and MUN increased to greater than 16 mg/dl, the likelihood ratio for pregnancy decreased. There was a high correlation between PUN and MUN concentrations (r²= 0.97, p≤ 0.001). The results of this study indicate that an increase in PUN or MUN can exert director indirect effects in reproduction, impairing the conception of grazing dairy cows.
- Avaliação do valor nutritivo e Identificação dos fitoestrogénios produzidos pelasplantas Pittosporum undulatum Vent., 1800 e Hedychium gardnerianum Ker-Gawler, 1828Publication . Nunes, Hélder Patrício Barcelos; Borba, Alfredo Emílio Silveira de; Silva, Joaquim Fernando Moreira daO Pittosporum undulatum Vent., 1800 e o Hedychium gardnerianum Ker-Gawler, 1828, conhecidas vulgarmente por faia e por conteira, são duas plantas invasoras dos Açores que, em períodos de maior escassez alimentar, são fornecidas aos ruminantes como alimentos volumosos, contudo pensa-se que seu fornecimento aos animais possa estar diretamente associado aos abortos verificados em algumas explorações dos Açores. Estas plantas poderão, por esse motivo, conter diversos metabólitos secundários, mais concretamente fitoestrogénios, que poderão influenciar a atividade sexual dos animais quando alimentados com estas plantas. Este estudo tem como objetivo avaliar o valor nutritivo e quantificar os diferentes tipos de fito-estrogénios presentes nestas plantas. […].
- O conhecimento do passado para apoiar, no futuro, a Agricultura, Zootecnia e Tecnologia de AlimentosPublication . Madruga, João; Borba, Alfredo Emílio Silveira de; Vouzela, Carlos Fernando Mimoso; Rosa, Henrique José Duarte; Rego, Oldemiro Aguiar do; Pires, Fernando Jorge da Rocha; Pinheiro, Jorge; Gomes, Anabela; Baptista, João; Batista, Edite; Depcevicius, Maria Lurdes; Silva, Célia; Lima, Elisabete; Baptista, José; Trota, Maria João; Barros, Maria João; Silva, Joaquim Fernando Moreira da; Fontes, José Carlos; Lima, Maria Teresa
- Effects of Plasma Urea Nitrogen Levels on the Bovine Oocyte Ability to Develop After In vitro FertilizationPublication . Santos, P.; Marques, A.; Antunes, G.; Chaveiro, António E.; Andrade, M.; Borba, Alfredo Emílio Silveira de; Silva, Joaquim Fernando Moreira daThe overall aim of the present study was to evaluate in vitro development ability of oocytes recovered from 56 Holstein Frisian heifers with low [group 1 (G1): <13 mg /dl], moderate [group 2 (G2): 13–16 mg /dl] and high [group 3 (G3): >16 mg /dl] plasma urea nitrogen (PUN) concentrations, to determine whether PUN concentrations affect the competence of oocytes to progress to blastocysts after in vitro fertilization. In vitro oocyte and embryo development was assessed by blastocyst rates, embryo total cell numbers and apoptosis. Blood samples for the determination of PUN were collected 24 h prior to collection of the ovaries at the slaughter. A total of 112 ovaries were collected at a local abattoir and oocytes (n = 697) were aspirated, in vitro matured and fertilized. On day 8, blastocysts were assigned to the terminal dUTP nick end labelling assay. Cleavage rates were significantly higher (p < 0.001) for groups 1 and 2 than for group 3 (i.e. 72.5% and 72.2% vs 61.7%, respectively). The proportion of fertilized oocytes that developed into blastocysts was higher (p < 0.05) for group 1 than for group 3 (34.0% vs 23.0%, respectively). Day 8 blastocysts showed higher total cell counts (p < 0.05) for group 1 than for group 3 (123.7 vs 76.3), and a higher (p < 0.05) total apoptotic cell rate was found in group 3 (25.9 and 19.0 vs 43.2 for G1, G2 and G3, respectively). In conclusion, the ability of oocytes from heifers with increased levels of PUN to develop to the blastocyst stage was significantly reduced when standard routines for in vitro maturation, fertilization and culture were followed. These detrimental effects can be mediated in part through direct effect of urea and/or by the metabolic products on the process of follicle-enclosed oocyte nuclear and cytoplasmic development.
- Pittosporum Undulatum and Hedychium Gardnerianum: nutritive value and secondary metabolites on cattle reproductive performancesPublication . Nunes, Hélder Patrício Barcelos; Falé, Pedro L.; Duarte, Maria F.; Serralheiro, Maria L.; Borba, Alfredo Emílio Silveira de; Silva, Joaquim Fernando Moreira daHedychium gardnerianum (HG) and Pittospporum undulatum (PU) are invasive plants all over the world, being in the Azores supplied to cattle on periods of shortage food. As these plants produce secondary metabolites, including a diverse range of phytochemicals compounds, the aim of the presente study is to identify how these metabolites can be related to animal’s reproductive performances. For such purpose, plants were harvested on winter, compounds extracted by method of decoction and analysed by combination of liquid chromatography and mass spectrometry as well as highperformance liquid chromatography. For nutritive evaluations, Van Soest and Weende methodologies were used. In HG quercetin-3, 4'-di-O-betaglucopyranoside, myricetin rhamnoside, quercetin rhamnoside, and gibberellin A1 and A8 were identified, while for PU were found cafeic acid derivatives, including dicaffeoylquinic acid and caffeoylquinic acid. In nutritional terms, these plants can be considered as poor, presenting percentages of dry matter (DM%) of 16.34% and 40.39%, respectively for HG and PU. Values for ash 10.4%, crude protein (CP) 7.75%, neutral detergent fiber (NDF) 64.5, acid detergent fiber (ADF) 34.69%, acid detergent lignin (ADL) 3.47% and ether extract (EE) 2.03% were found for HG. For PU values were ash 6.64%, CP 6.11%, NDF 43.84%, acid ADF 35.57%, ADL 3.56% and EE 2.71%. This study clearly indicated that, besides their low nutritive values, these plants can be used to feed ruminants, especially when pasture lacks. Nevertheless, as some compounds, namely the caffeoylquinic and dicaffeoylquinic acids, are known to be associated to physiological reproductive mechanisms, one could speculate that these compounds can be directly or indirectly associated to reproductive performances in bovine fed with these plants.