Percorrer por autor "Moreira, Olga"
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- Characterization of collagen and fatty acid composition of “Carne Mirandesa-PDO” vealPublication . Galvão, Lurdes; Moreira, Olga; Bessa, Rui; Alves, S.P.; Sousa, Fernando Ruivo de; Ribeiro, José Ramalho; Alves, VirgílioThe objective of this study was to evaluate chemical parameters related to meat quality, contributing to a better characterization of “Carne Mirandesa-PDO” veal. This study was made in three farms, from the Northeast region of Portugal (PG, FA1 and FA2), where calves were raised permanently indoors, nurse from their dams overnight, and fed with hay and concentrate made with local ingredients and soybean meal. Twenty five calves were slaughtered at 7 months old. Twenty four hours after slaughter, samples were collected from four different muscles: longissimus dorsi (LD), semimembranosus (SM), gluteus biceps femoris (GB) and triceps brachii caput longum (TBL), vacuum packaged and freeze-dried. Determinations of crude protein (CP), ether extract (EE), collagen and fatty acid were made. Collagen, CP and EE were significantly (p<0.001) affected by muscle type. Fatty acid composition was mostly affected by farm and by muscle type. The SM muscle was poor in saturated fatty acids (14:0, 15:0, 16:0, 17:0 and 18:0) and richer in polyunsaturated fatty acids than the other muscles. The ratio between n-3 and n-6 PUFA observed in this study are close to the usually found for pasture fed animals indicating the healthy value of “Carne-Mirandesa PDO” veal.
- Dynamics of pastures and fodder crops for Mirandesa cattle breedPublication . Galvão, Lurdes; Moreira, Olga; Valentim, Ramiro; Ribeiro, José Ramalho; Alves, VirgílioMirandesa cattle are a local breed from the Northeast region of Portugal, playing na important role on the maintenance of the rural spaces, contributing to the fixation of the populations ant to the environmental preservation. The aim of this study is to characterize the feed resources available along the year in this farming system. The animals graze natural pastures in Spring and beginning of Summer, being after fed with hays (of natural pasture or oat) and straws (oat, barley or wheat) and complemented with local feeds like squash or potatoes. Samples of feed were taken from three different farms in two consecutive years and analysed for crude protein (CP), cell wall components, minerals and in vitro organic matter digestibility (OMD). Data were evaluated using ANOVA statistical approach. Seasonal variations were observed in natural pastures with decreases of CP from Spring to Summer (16.0 to 9.4% DM) and increases of NDF content from 32 to 41% DM. Consequently a reduction of OMD from 69 to 58% was observed. Regarding hays composition, differences were observed for CP content which was lower for oat hay, compared with that from natural (2.4 vs. 4.6% DM). Straw quality varied between farms and type of straw.
- Dynamics of pastures and fodder crops for Mirandesa cattle breed - II Mineral compositionPublication . Galvão, Lurdes; Moreira, Olga; Sousa, Fernando Ruivo de; Valentim, Ramiro; Correia, Teresa Montenegro; Ribeiro, José Ramalho; Alves, VirgílioMirandesa cattle are a local breed from the Northeast region of Portugal, playing an important role on the maintenance of the rural spaces, contributing to the fixation of the populations and to the environmental preservation. The aim of this study is to characterize the feed resources (mineral composition) available along the year in this farming system. The animals graze natural pastures in Spring and beginning of Summer, being after fed with hays (of natural pasture or oat) and straws (oat, barley or wheat). Samples of feeds were taken from three different farms in two consecutive years and analysed for crude protein (CP), cell wall components, minerals and in vitro organic matter digestibility (OMD). Data were evaluated using ANOVA statistical approach. Results of organic composition of feeds were presented by Galvão et al. (EAAP, 2005). For mineral composition, seasonal variations were observed in natural pastures with decreases of K and P (from Spring to Summer 2 to 0.97 and 0.33 to 0.18% DM, respectively). Farm variations were observed for Ca, K and Mg. Regarding hays composition, differences were observed for Ca and Mg contents which was lower for oat hay, compared with that from natural pasture (0.16 vs 0.32 and 0.08 vs 0.15% DM, respectively). The composition of straws varied between farms and type of straw.
- Prediction of apparent digestibility of hays from natural pastures of the Northeast region of PortugalPublication . Galvão, Lurdes; Guedes, Cristina M.; Rodrigues, M.A.M.; Silva, S.R.; Valentim, Ramiro; Moreira, Olga; Ribeiro, José Ramalho; Sequeira, C.A.In the Northeast region of Portugal hays from natural pastures are traditionally used as the main feed during the period of drought and the evaluation of its nutritive value is essential. The aim of this study was to predict the apparent organic matter digestibility (OMD) of 21 hays from natural pastures based on chemical composition, pepsin-cellulase solubility of organic matter (OMS) and in vitro organic matter digestibility. Chemical composition of hays showed a wide range of values and acid detergent lignin (ADL) was the component that presented the highest variation (CV = 18.4%). The OMD varied between 516 and 658 g/kg OM. The best single OMD predictor was OMS (RSD = 2.8%, R2 = 0.52, P<0.001). Using multiple regression to predict OMD, the variables included in the model were OMS and ADL (OMD = 21.51 + 0.94 OMS – 0.83 ADL; RSD = 2.75%; R2 = 0.54; P<0.0001). According to principal component analysis (PCA) hays were divided in 3 groups and the multiple regression established for the larger group of hays (n=10) was: OMD = 4.13 + 0.85 OMS – 1.03 ADL; RSD = 2.13%, R2 = 0.77, P<0.0001. The OMS method was superior to chemical composition and to the in vitro rumen fluid method in predicting OMD of hays from natural pastures. Results from PCA suggested that it may be useful to group these hays according to its chemical composition to accurately predict OMD.