| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 7.47 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
Dada a tendência global crescente por busca de soluções que garantem o uso racional
de recursos e sistemas sustentáveis de produção de alimentos, gerada pelo crescimento
acelerado da população e pelas mudanças nos padrões climáticos, dois estudos foram conduzidos
na Quinta do Pinheiro Manso da Escola Superior Agrária de Bragança, com vista
a fazer face a estes desafios que a humanidade enfrenta.
O primeiro estudo foi realizado com o objetivo de avaliar a evolução do crescimento
Primaveril e da qualidade das pastagens de sequeiro Mediterrânicas no Nordeste Transmontano
de Portugal, concretamente na Quinta do Pinheiro Manso. Para tal, foram efetuados
cortes quinzenalmente das amostras de pastagem a uma altura de 2 cm do solo,
em quadrícula de 50 cm x 50 cm, ao longo da Estação de crescimento supra referida. A
seguir a cada corte, as amostras eram pesadas e desidratadas em uma estufa com ventilação
forçada a 65ºC, e depois tirado o peso da matéria seca (MS). A proteína bruta (PB)
e Fibra das amostras foram determinadas em amostras desidratadas a 105ºC seguindo-se
respetivamente os procedimentos de kjeldahl e Van Soest. As observações da composição
florística (CF) foram efetuadas em três momentos, Outono, Inverno e Primavera, pelo
método de Pontos Quadrados de Levy. Ainda neste estudo foram ajustados modelos não
lineares ao crescimento da pastagem, com recurso ao método de mínimos quadrados não
lineares. Os dados foram analisados em R. Do Outono à Primavera foi observada uma
variação em termos da CF, onde a fração das leguminosas aumentou (p<0,05) de 12,23
± 4,38% para 32,70 ± 6,077%, as gramíneas não variaram (p>0,05), a fração de solo nu
reduziu (p<0,05) de 19,10 ± 4,081% para 0,52 ± 0,369% e as outras espécies reduziram
(p<0,05) de 38,92 ± 5,234% no Inverno para 21,52 ± 5,625% na Primavera. A produção
cumulativa da MS durante a Primavera foi de cerca de 6,2t/ha e a média ao longo dos
cortes efetuados foi de 1,04t/ha. Ao longo da mesma Estação Primaveril, a PB teve tendência
de reduzir com a evolução do tempo e a Fibra aumentou. Os modelos Logístico, de Weibull, de Ratkowsky e de Gompertz ajustaram a curva de crescimento Primavril da
pastagem de sequeiro e o modelo de Weibull foi o que ajustou com melhor qualidade.
O segundo estudo, foi realizado com o objetivo de avaliar o efeito da adição de uma
mistura de algas marinhas no crescimento e nos atributos de qualidade da carcaça e da
carne de cordeiros. Este ensaio teve lugar no mesmo espaço referenciado no primeiro estudo,
tendo sido para o efeito utilizados 30 cordeiros da raça Bordaleira-de-Entre-Douroe-
Minho, divididos em 3 lotes homogéneos de 10, relativamente ao sexo, tipo de parto
e peso vivo (PV) no início do ensaio. Os lotes foram aleatoriamente alocados a três tratamentos:
alimento concentrado com adição de 5% de mistura de algas (CA), alimento
concentrado (CO) e pastoreio (PA). Todos os cordeiros tiveram acesso ad libitum a água e
a feno de prado natural, foram pesados quinzenalmente e o PV foi utilizado para calcular o
ganho médio diário (GMD). Após 60 dias de experiência, os cordeiros foram abatidos, as
carcaças foram refrigeradas a 4ºC durante 24h, após o qual se obteve o peso de carcaça fria
(PCF), tendo-se calculado os rendimentos em carcaça (RCF). A gordura pélvica e renal
(GPR) foi removida e pesada. O pH, a capacidade de retenção da água (CRA) avaliada
pelas perdas por exsudação e por cocção, a cor (CIELAB) e a tenrura (Warner-Bratzler-
Shear-Force) da carne foram medidos no músculo Longissimus lumborum, após 7 dias de
maturação embalado a vácuo e armazenado a 4ºC. Os dados foram analisados com o software
R. Os cordeiros do tratamento PA apresentaram menor (p<0,05) GMD (102±8,750
g/dia) e não se observaram diferenças (p>0,05) entre os tratamentos CA (173±11,396 g/-
dia) e CO (157±15,931 g/dia). Ao comparar-se o GMD antes e durante o ensaio, este
aumentou (p<0,05) no tratamento CA, manteve-se (p>0,05) no tratamento CO e diminuiu
(p<0,05) no tratamento PA. Comparativamente aos cordeiros do tratamento PA, os dos
tratamentos CA e CO apresentaram maior (p<0,05) PCF (7,56±0,289 versus 11,02±0,635
e 9,88±0,331 Kg), maior (p<0,05) RCF (40,4±0,774 versus 44,9±0,595 e 45,2±0,515%)
e maior (p<0,05) GPR (187,5±18,162 versus 318,8±35,250 e 322,2±36,430 g). Todas as
carcaças apresentaram pH inferior a 5,70 e não se observaram diferenças (p>0,05) entre os
tratamentos na cor, na tenrura e na CRA. A formulação de alimento concentrado com 5%
da mistura de algas mostrou potencial para melhorar a taxa de crescimento dos cordeiros.
Given the growing global trend to search for solutions that ensure the rational use of resources and sustainable food production systems, generated by rapid population growth and changing weather patterns, two studies were conducted at Quinta do Pinheiro Manso of Escola Superior Agrária de Bragança (ESAB), in order to address these challenges facing humanity. The first study was conducted with the aim of evaluating the evolution of Spring growth and quality of Mediterranean dryland pastures in the Northeast Transmontano of Portugal, specifically at Quinta do Pinheiro Manso. For this purpose, fortnightly grass samples were cut at a height of 2 cm from the soil, in 50 cm x 50 cm grid, during the above mentioned growing season. After each cut, the samples were weighed and dehydrated in an oven with forced ventilation at 65ºC, and then the weight of dry matter (DM) was taken. The crude protein (CP) and Neutral Detergent fibre (NDF) of the samples were determined on dehydrated samples at 105ºC following respectively the Kjeldahl and Van Soest procedures. Observations of floristic composition (FC) were made at three moments, autumn, winter and spring, by Levy’s Square Point Method. Also in this study non-linear models were fitted to the growth of the grassland, using the non-linear least squares method. The data were analysed in R. From autumn to spring a variation was observed in terms of FC, where the legume fraction increased (p<0,05) from 12,23 ± 4,38% to 32,70 ± 6,077%, grasses did not vary (p>0, 05), the bare soil fraction reduced (p<0,05) from 19,10 ± 4,081% to 0,52 ± 0,369% and the other species reduced (p<0,05) from 38,92 ± 5,234% in winter to 21,52 ± 5,625% in spring. The cumulative yield of DM during spring was about 6,2t/ha and the average over the cuts made was 1,04t/ha. Over the same spring season, CP tended to reduce over time and fibre (NDF) increased. The Logistic, Weibull, Ratkowsky and Gompertz models adjusted the spring growth curve of the dryland pasture and the Weibull model was the one that adjusted with better quality. The second study was conducted with the aim of evaluating the effect of adding a mixture of seaweed on the growth and quality attributes of the carcass and meat of lambs. This trial was carried out in the same space referred to in the first study. For this purpose, 30 lambs of the Bordaleira-de-Entre-Douro-e-Minho breed were used, divided into 3 homogeneous groups of 10, regarding to sex, type of birth and live weight (BW) at the beginning of the trial. The groups were randomly allocated to three treatments: concentrated feed with the addition of 5 % algae mix (CA), concentrated feed (CO) and grazing (PA). All lambs had ad libitum access to water and natural meadow hay, were weighed fortnightly and live weight (LW) was used to calculate average daily gain (ADG). After 60 days of trial, the lambs were slaughtered, carcasses were refrigerated at 4°C for 24h, after which cold carcass weight (CCW) was obtained and carcass yields (CCY) were calculated. Pelvic and kidney fat (PKF) was removed and weighed. The pH, water holding capacity (WHC) assessed by exudation and cooking losses, colour (CIELAB) and tenderness (Warner-Bratzler-Shear-Force) of the meat were measured in the Longissimus lumborum muscle after 7 days of maturation vacuum packed and stored at 4°C. The data were analysed with R software. Lambs in PA treatment showed lower (p<0,05) ADG (102±8,750 g/day) and no differences (p>0,05) were observed between CA (173±11,396 g/day) and CO (157±15,931 g/day) treatments. When comparing the ADG before and during the trial, it increased (p<0,05) in the CA treatment, maintained (p>0,05) in the CO treatment and decreased (p<0,05) in the PA treatment. Compared to the lambs in the PA treatment, those in the CA and CO treatments showed higher (p<0,05) CCW (7,56±0,289 versus 11,02±0,635 and 9,88±0,331 Kg), higher (p<0,05) CCY (40,4±0,774 versus 44,9±0,595 and 45,2±0,515%) and higher (p<0,05) PKF (187,5±18,162 versus 318,8±35,250 and 322,2±36,430 g). All carcasses showed pH lower than 5,70 and no differences (p>0,05) were observed between treatments in colour, tenderness and WHC. The formulation of concentrated feed with 5% of the algae mixture showed potential to improve the growth rate of lambs.
Given the growing global trend to search for solutions that ensure the rational use of resources and sustainable food production systems, generated by rapid population growth and changing weather patterns, two studies were conducted at Quinta do Pinheiro Manso of Escola Superior Agrária de Bragança (ESAB), in order to address these challenges facing humanity. The first study was conducted with the aim of evaluating the evolution of Spring growth and quality of Mediterranean dryland pastures in the Northeast Transmontano of Portugal, specifically at Quinta do Pinheiro Manso. For this purpose, fortnightly grass samples were cut at a height of 2 cm from the soil, in 50 cm x 50 cm grid, during the above mentioned growing season. After each cut, the samples were weighed and dehydrated in an oven with forced ventilation at 65ºC, and then the weight of dry matter (DM) was taken. The crude protein (CP) and Neutral Detergent fibre (NDF) of the samples were determined on dehydrated samples at 105ºC following respectively the Kjeldahl and Van Soest procedures. Observations of floristic composition (FC) were made at three moments, autumn, winter and spring, by Levy’s Square Point Method. Also in this study non-linear models were fitted to the growth of the grassland, using the non-linear least squares method. The data were analysed in R. From autumn to spring a variation was observed in terms of FC, where the legume fraction increased (p<0,05) from 12,23 ± 4,38% to 32,70 ± 6,077%, grasses did not vary (p>0, 05), the bare soil fraction reduced (p<0,05) from 19,10 ± 4,081% to 0,52 ± 0,369% and the other species reduced (p<0,05) from 38,92 ± 5,234% in winter to 21,52 ± 5,625% in spring. The cumulative yield of DM during spring was about 6,2t/ha and the average over the cuts made was 1,04t/ha. Over the same spring season, CP tended to reduce over time and fibre (NDF) increased. The Logistic, Weibull, Ratkowsky and Gompertz models adjusted the spring growth curve of the dryland pasture and the Weibull model was the one that adjusted with better quality. The second study was conducted with the aim of evaluating the effect of adding a mixture of seaweed on the growth and quality attributes of the carcass and meat of lambs. This trial was carried out in the same space referred to in the first study. For this purpose, 30 lambs of the Bordaleira-de-Entre-Douro-e-Minho breed were used, divided into 3 homogeneous groups of 10, regarding to sex, type of birth and live weight (BW) at the beginning of the trial. The groups were randomly allocated to three treatments: concentrated feed with the addition of 5 % algae mix (CA), concentrated feed (CO) and grazing (PA). All lambs had ad libitum access to water and natural meadow hay, were weighed fortnightly and live weight (LW) was used to calculate average daily gain (ADG). After 60 days of trial, the lambs were slaughtered, carcasses were refrigerated at 4°C for 24h, after which cold carcass weight (CCW) was obtained and carcass yields (CCY) were calculated. Pelvic and kidney fat (PKF) was removed and weighed. The pH, water holding capacity (WHC) assessed by exudation and cooking losses, colour (CIELAB) and tenderness (Warner-Bratzler-Shear-Force) of the meat were measured in the Longissimus lumborum muscle after 7 days of maturation vacuum packed and stored at 4°C. The data were analysed with R software. Lambs in PA treatment showed lower (p<0,05) ADG (102±8,750 g/day) and no differences (p>0,05) were observed between CA (173±11,396 g/day) and CO (157±15,931 g/day) treatments. When comparing the ADG before and during the trial, it increased (p<0,05) in the CA treatment, maintained (p>0,05) in the CO treatment and decreased (p<0,05) in the PA treatment. Compared to the lambs in the PA treatment, those in the CA and CO treatments showed higher (p<0,05) CCW (7,56±0,289 versus 11,02±0,635 and 9,88±0,331 Kg), higher (p<0,05) CCY (40,4±0,774 versus 44,9±0,595 and 45,2±0,515%) and higher (p<0,05) PKF (187,5±18,162 versus 318,8±35,250 and 322,2±36,430 g). All carcasses showed pH lower than 5,70 and no differences (p>0,05) were observed between treatments in colour, tenderness and WHC. The formulation of concentrated feed with 5% of the algae mixture showed potential to improve the growth rate of lambs.
Description
Keywords
Pastagem de sequeiro Modelação de crescimento Crescimento de cordeiro Qualidade de carne