فهرست مقالات Preference value

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  1 - Determining the Preference Value of Perennial Grasses Using Preference Index and Sheep Grazing Time Methods in Grasslands of the Middle Alborz, Iran
  Saeed Rashvand Hassan Yeganeh Fazel Amiri
  Preference value means livestock preference to eat some plants relative to other plants or species. Accordingly, by studying the preference values, the range managers could determine the rangelands grazing capacity to achieve the optimum performance of livestock and to چکیده کامل

  Preference value means livestock preference to eat some plants relative to other plants or species. Accordingly, by studying the preference values, the range managers could determine the rangelands grazing capacity to achieve the optimum performance of livestock and to guarantee the stability of rangeland ecosystem. The objective of this study was to determine the preference value of perennial grasses using two methods of preference index (species feeding frequency) and sheep grazing time (feeding time recording) in a semi-steppe rangeland in the middle Alborz Mountains of Iran during four consecutive years (2010-2013). The collected data were tested for normality and then, analyzed by the software of SAS9.1. The means comparisons were made using the Duncan method. Results showed that sheep preferred five grass species (Bromus tomentellus, Festuca ovina, Dactylis glomerata, Agropyron intermedium, and Agropyron trichophorum) in the rangeland. There were significant differences between species and years for grazing time method; however, there were no significant differences for preference index. Also, there were significant differences between months within years for both methods. Results showed that A. trichophorum with the average value of 13.8% grazing time was ranked as the first species followed by D. glomerata with the average value of 11.1% as the second one (Grazing time method). There were no significant differences between A. trichophorum, B. tomentellus, D. glomerata and F. ovina regarding the preference index with the average values of 0.57, 0.75, 0.70 and 0.56, respectively. Overall, the results indicated that grazing time percent method in semiarid rangelands gives more realistic results as compared to the preference index method because of the concrete and tangible results. پرونده مقاله
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  2 - Preference Value Evaluation of Rangeland Plant Species for Kaboudeh Sheep
  Reza Erfanzadeh Moharam Ashrafzadeh Seyed Hamzeh Hosseini Kahnuj Arezu Alizadeh
  Study on the livestock diet is one of the main priorities in the management of rangeland in Iran. So, this study was conducted to compare preference values of plant species in three age classes of Kaboudeh sheep (one, three and five year old ones) in rangelands of Bavan چکیده کامل

  Study on the livestock diet is one of the main priorities in the management of rangeland in Iran. So, this study was conducted to compare preference values of plant species in three age classes of Kaboudeh sheep (one, three and five year old ones) in rangelands of Bavanat, Fars province, Iran. For each age class, four sheep were selected and their grazing times from different plant species were recorded using a timing method (chronometer) for two hours during the day. The effects of livestock age, plant species and their interactions on preference values of plant species were assessed using a factorial experiment (GLM test). Also, one way ANOVA was applied to compare preference values between plant species for each age class of animals. The results showed that the age of the animals and plant species had significant effects on preference values of plant species. Species of Poa pratensis and Avena fatua for young animals and Acer cinerascens for older animals had higher preference values. In addition, species of Poa pratensis and Prangos ferulaceae had appropriate preference values for all three age classes of animals. As vegetation cover in the study area is mostly consisted of the bushes and shrubs in autumn and on the other hand, sheep has little ability to graze this kind of plant species subsequently during the grazing period, they dominantly focus on herbal species. In general, animal diet demands cannot be provided from rangelands and it is required to use the methods of manual feeding with dry forage and supplements. One of the possible alternatives is to harvest and store the annual yield of P. ferulaceae in spring in order to feed the animals in autumn and winter. پرونده مقاله
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  3 - The Study of Preference Values of Forage Species and Grazing Behavior of Tali Goat in Chabahar Rangelands of Iran
  Parvaneh Ashouri Sanjabi Mohammad Fayaz Niloufar Zare Ahmad Gharanjik Hassan Yeganeh Shahram Afrougheh
  In recent years, studying the dietary preferences and livestock grazing behaviorhas attracted lots of attention due to manage and improve the efficiency of rangelands. So,in this study the foraging behavior and diet selection of Tali goat was investigated in theChabahar چکیده کامل

  In recent years, studying the dietary preferences and livestock grazing behaviorhas attracted lots of attention due to manage and improve the efficiency of rangelands. So,in this study the foraging behavior and diet selection of Tali goat was investigated in theChabahar Rangeland during 2008-2010. Data were collected and analyzed for speeds oflivestock, covered distance, time of grazing, resting, and walking for months of grazing(February to May) as replications over 3 years. To determine the preference value, timerecorder method was used. Time of grazing of specific plant species by livestock wasmonthly recorded and analyzed, across February to April. Results showed that Launaeamucronata species of annual broad-leaved had the highest preference value while twospecies of Sporobolus arabicus and Lotononis platycarpos had the lowest ones. All themeasured parameters of grazing behavior had no significant differences during the studiedyears. The resting time rates of various months had significant differences. Accordingly,the highest resting time rate could be attributed to May whereas this rate was likely to bereduced during February, March and April. The result of the study will therefore be usefulin planning a grazing strategy and determination of carrying capacity for livestock grazingin the studied rangelands. Also the findings help us in rehabilitate Chabahar rangelands,with palatably species for the Tali goats. پرونده مقاله