Hossein Arzani; vahideh Abdollahi; Javad Motamedi; Majid Akhshi
Abstract
Nowadays, most attention is focused on physical and non-destructive methods, such as NIRS, to measure the chemical composition of rangeland species. Therefore, the purpose of this study is to provide calibration models for Infrared NIRS to estimate the forage quality of shrub species, so that in addition ...
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Nowadays, most attention is focused on physical and non-destructive methods, such as NIRS, to measure the chemical composition of rangeland species. Therefore, the purpose of this study is to provide calibration models for Infrared NIRS to estimate the forage quality of shrub species, so that in addition to saving time and cost, the quality of these plants could be estimated with proper accuracy. For this purpose, 654 samples of vegetative, flowering and seeding stages were irradiated by the DA7200 Perten Instrument to estimate the values of nitrogen (N), crude protein (CP), acid detergent fiber (ADF), dry matter digestiblility (DMD) and metabolizable energy (ME) via NIRS. Then, the data were transferred to the Unscrambler software for multivariate analysis. Before fitting the model, S.Golay and SNV methods were used for normalization of data distribution. Calibration and validation of model were performed using PLS1 method and Cross Validation method, respectively. Then, the predictability of models was evaluated by considering the calibration statistics. A total of 18 calibration programs were developed. Considering the calibration statistics, it could be said that the coefficient of determination was above 80% in all the factors studied. Also, at all growth stages, the correlation coefficient between the reference data and the data estimated by NIR was above 90%. Our results clearly showed that NIR calibrations obtained in this study could be used in current and future programs to assess the forage quality of shrub species used by livestock.
Hossein Arzani; javad Motamedi(torkan); Mahmood Hamidian; Zahra Arzani; Majid Akhshi
Abstract
To achieve the desired level of animal performance providing animal food supplies containing mineral elements is essential. For this purpose, mineral elements of 8 important rangeland species, including Ferula ovina, Prangus uloptera, Medicago sativa, Lotus goeblia, Trifolium montanum, Melilotus officinalis, ...
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To achieve the desired level of animal performance providing animal food supplies containing mineral elements is essential. For this purpose, mineral elements of 8 important rangeland species, including Ferula ovina, Prangus uloptera, Medicago sativa, Lotus goeblia, Trifolium montanum, Melilotus officinalis, Sanguisorba minor and Stachys inflate, were measured at different growth stages in the summer pastures of Taleghan. Therefore, at each growth stage 3 samples were taken and for each sample at least five vegetable bases were removed from different vegetation types. Data were analyzed using one-way ANOVA and to see the sources of variation within groups the Duncan test was utilized. Moreover, T-test was used to compare the values of mentioned elements with the critical level to provide the daily requirements of an animal unit in the maintenance mode. The results show that the values of minerals at the early stages of growth are more than those at the final stages of development (seeding stage). Moreover, the mentioned values in each stage of the growth are not uniform among the studied species. In general, the studied species are in good condition in terms of the calcium, iron, copper, cobalt and manganese values for meeting the daily needs of animals. However, they are not in optimal condition in terms of the highly consumed elements such as sodium and magnesium values at different growth stages, especially at later stages of growth, for meeting the daily needs of animals. This indicates that the desirability of grassland forage at different times of grazing is not identical regarding the mineral elements. It is normal that depending on the year’s conditions the values of plant mineral elements may change slightly; however, due to the cost of determining mineral elements, the results can be used to estimate the daily animal needs in different years.
