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Several experiments were performed in spring summer over the period 1982–85 to study the relationships between digestibility of energy (DE), gross energy intake (GEI), acid detergent fibre (ADF) and dry matter (DM) content in pasture.
Wether sheep in metabolism pens and fed ad libitum with daily-cut fresh pasture were used. Two plots with different botanical composition were used to provide herbage; one dominated by Lolium perenne and the other by Holcus lanatus. A high correlation ( r = -0·91) was observed between DE and ADF. The prediction used a second-order degree polynomial.
Gross energy intake and digestibility of energy were scarcely correlated ( r = 0·50) when all cases as a whole were considered. Higher correlations between GEI and DE ( r = 0·69) were obtained when only data from pastures where Holcus lanatus prevailed were considered, and still higher ( r = 0·91) in those pastures dominated by sown species with DE values lower than 70%.
Herbage DM content had a large effect on GEI( r = 0·83) in the pastures dominated by perennial ryegrass with DE higher than 70%, the correlation between DE and GEI being low and negative ( r =-0·36). It is possible, therefore, to predict apparent digestibility of pasture energy from ADF. However, DE is closely related to GEI only in those pastures in which DE is lower than 70%, DM content being an important factor limiting the intake of those fresh pastures dominated by Perennial ryegrass when DE is above 70%. 相似文献
Wether sheep in metabolism pens and fed ad libitum with daily-cut fresh pasture were used. Two plots with different botanical composition were used to provide herbage; one dominated by Lolium perenne and the other by Holcus lanatus. A high correlation ( r = -0·91) was observed between DE and ADF. The prediction used a second-order degree polynomial.
Gross energy intake and digestibility of energy were scarcely correlated ( r = 0·50) when all cases as a whole were considered. Higher correlations between GEI and DE ( r = 0·69) were obtained when only data from pastures where Holcus lanatus prevailed were considered, and still higher ( r = 0·91) in those pastures dominated by sown species with DE values lower than 70%.
Herbage DM content had a large effect on GEI( r = 0·83) in the pastures dominated by perennial ryegrass with DE higher than 70%, the correlation between DE and GEI being low and negative ( r =-0·36). It is possible, therefore, to predict apparent digestibility of pasture energy from ADF. However, DE is closely related to GEI only in those pastures in which DE is lower than 70%, DM content being an important factor limiting the intake of those fresh pastures dominated by Perennial ryegrass when DE is above 70%. 相似文献
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An Urban Approach to Firm Entry: The Effect of Urban Size 总被引：1，自引：0，他引：1
ABSTRACT This article explores the determinants of firm entry in Spanish municipalities. The authors consider that size is an important determinant of a city's capacity to attract new manufacturing firms. Panel data were used to estimate the determinants of entry according to urban size in Spain (from 1994 to 1702). This article contributes to the literature on market entry because most previous contributions have focused on regional factors rather than urban ones. The results show that local characteristics affect the formation of new firms. However, more local data are needed to obtain more specific results. 相似文献
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