Study on Productivity and Plant Preference by Sheep and Goats Grazing Natural Rangelands in El Domokeya area North Kordofan Sudan

Abstract

This study was conducted in El Demokeya forest, a protected rangeland, in Sheikan Locality, North Kordofan State. The forest lies about 31 km east of the city of El Obeid. Another rangeland in northeast of El Demokeya Forest was also selected for use as a control open rangeland. The main objective of this study was to examine the interactions between plants and animals (sheep and goats) and implications for the management of natural rangelands in North Kordofan. Plant measurements were taken in an area of one km2 inside and outside the forest (along eight radiating transects of 500 meter each). Measurements of plant species composition, biomass production, plant density and frequency, the amount of forage available from shrubs and density of trees in the protected and open rangeland were conducted. The nutritional value of rangeland was evaluated by determination of the chemical composition of range plants in the protected and open rangeland and also by assessing voluntary feed intake by sheep and goats using the product of the quantity of faeces collected over a specific period of time and in vitro digestion coefficient of forage plants selected by sheep and goats. The selection of plants by sheep and goats was determined using the bite count technique. The investigation of the social and economic aspects of livestock management in North Kordofan and their impact on the use of rangelands was done through the collection of data from the livestock raisers using a questionnaire. The results of measurements of the plant species composition in the range showed that there were differences between the protected and open rangelands (81.9% and 87.5% respectively). It was found that the plants Echinocloa colonum (Difra) and Zaleya pentandra (Rabaa) have formed the highest relative composition in protected site 27.9% and 21.8% respectively, while in the open site Fimbristyls dichotoma (Um fisiysiat) and Cenchrus biflorus (Haskaneet) showed the highest relative composition, 37. 1% and 16.8% respectively. The vegetation cover percentage was 54.7% in the protected site and 40.7% in the open site. The results showed significant differences for plant density between the protected and open rangeland (260.9 and 181.9 plants / m 2), respectively. Zaleya pentandra (Rabaa) had highest frequency in the protected rangeland (85%), while in the open rangeland Fimbristyls dichotoma (Um fisiysiat) formed highest frequency (85.2%). There were very highly significant differences in productivity between the protected and open rangeland at flowering and seed setting seasons. The productivity of rangeland at flowering season on protected site was 4.5 ton / ha, while it was 2.3 ton/ ha in the open rangeland. In the season of seed setting productivity was 1.4 ton / ha, in the protected site, but only 1.0 ton / ha in the open site. The dominant plants in the protected site were Aristida mutabilis (Gaw), Echinocloa colonum (Difra), Fimbristyls dichotoma (Um fisiysiat), Zaleya pentandra (Rabaa) and Geigeria alata (Gdgad), while the dominant plants in the open site were Eragrostis tremula (Bano), Cenchrus biflorus (Haskaneet), Echinocloa colonum (Difra) and Aristida mutabilis (Gaw). The results of chemical analysis of some herbaceous plants and trees in the study area showed, that Ipomoea blepharosepala (Hantoot) and Echinocloa colonum (Difra) had the highest crude protein content of 18.7 and 18% respectively, among the former group while Acacia senegal (Hashab) had the highest level of crude protein in the latter, 20.9%. It was found that there were significant differences in the nutritional value of rangeland biomass (protected and open) between the seasons of flowering and seed set in the crude protein content. The percentage of crude protein in the protected site at the season of flowering was 6.8% while in the season of seed setting it was 5.7%. In the open site at the flowering season, the percentage of crude protein was 3.5% while in the season of seed setting it was 3.2%. There were highly significant differences in crude protein content of rangeland between the protected and open site in both seasons (flowering, seed set). The chemical analysis of the plants selected by sheep and goats showed highly significant differences in the crude protein content between the seasons of flowering and seed setting in the protected site and also in the open site. The plants selected by sheep in the flowering season at the protected site were Ipomoea blepharosepala (Hantoot) 19.2% and Cenchrus biflorus (Haskaneet) 14.1%, which accounted for the highest proportion of plants selected, while in the open site the plants selected, were Cenchrus biflorus (Haskaneet) 42% and Echinocloa colonum (Difra) 12.8%. The most important plants selected by sheep during grazing in the seed set season in the protected site were Aristida mutabilis (Gaw) 22.3% and Tephrosia spp. (Fresha) 12.8% which accounted for the highest percentage of the plants chosen, while in the open site the plants selected were Eragrostis tremula (Bano) 68% and Aristida mutabilis (Gaw) 21.9 %. The selection by goats during the flowering season in the protected site was highest for Acacia senegal (Hashab) 26.6% and Echinocloa colonum (Difra) 11.3%, while in the open site the highest selection was for Acacia senegal (Hashab) 22.6% and Eragrostis tremula (Bano) 13.8%. In the season of seed setting the selection of goats in the protected site was high for Justica kotschyi (Naʼna) 18.4% and for Acacia senegal (Hashab) 15%, while in the open site goats showed preference to Eragrostis tremula (Bano) 52.9% and Acacia senegal (Hashab) 25.6%. The data on feed intake by Sheep and goats showed that, there were no significant differences between the protected and open rangeland in the flowering season. The amount of food eaten in the protected rangeland by sheep and goats was 1199.5 and 1259.3 g of dry matter/day, respectively, while in the open rangeland it was 1339.3 g of dry matter/day for the sheep and 1232.9 g/DM/day for goats. The distance walked by the animals during grazing showed highly significant differences between the type of animal (sheep or goats) and between the seasons of flowering and seed setting. It was found that in the protected site at the flowering season sheep and goats walked a distance of 4.9 km / day, while during the seed setting season the sheep, walked 8.3 km / day and the goats, 4.4 km / day. In the open site at the flowering season the sheep walked a distance of 12.4 km / day, while goats walked 5.3 km / day. In the season of seed setting the sheep, walked a distance of 13.9 km/day and the goats 7.3 km/day. The results of metabolizable energy concentration (Mcal /kg DM) in the feed intake (selected plants) by sheep and goats showed that there were no significant differences between the seasons of flowering and seed setting and also between protected and open sites. Moreover there were no significant differences in the amount of metabolizable energy intake (MEI Mcal / day) by the sheep and goats in the protected and open sites. The metabolizable energy in the feed selected by the sheep and goats in the protected site at the flowering season was 1.9 and 2.3 (Mcal / Kg DM), respectively. The value of the metabolizable energy intake by sheep was 2.4 (Mcal / day) and that by goats was 2.9 (Mcal / day). Crude protein intake by sheep and goats showed highly significant differences between the season of flowering and seed setting and also between protected and open sites. The average crude protein intake by sheep and goats in the protected site in the flowering season was 105.6 and 137.6 g / animal / day, respectively. The average crude protein intake for sheep and goats in the open site in the flowering season was 63.1 and 157.5 g / animal / day, respectively. The study concluded that these findings should be taken into consideration in the process of range pasture management. The preferred plants for both sheep and goats must be made use of in the rehabilitation of the rangelands of North Kordofan. From the findings of this research the most preferred plants by sheep were Ipomoea blepharosepala (Hantoot), Cenchrus biflorus (Haskaneet) and Tephrosia spp. (Fresha), The most preferred plants by goats were Acacia senegal (Hashab), Gyndropsis gynandra graecizans (Tamaleika), Corchorus olitorius (Molokhya). The study found that sheep walked longer distance than goats during grazing specially at seed setting stage, Therefore, the quality of range must be improved. Seeds of plants of high nutritive value should be sprinkled to meet the energy requirements of animals for maintenance and production. Also the conservation and storage of the range plants to provide energy for production should be encouraged. A well vegetated rangeland with good cover comprising preferred species should be a major objective of range development. This, coupled with good distribution of water sources, should result in a reduction in the energy cost for walking and thereby availing more metabolizable energy for production. Rangelands are found to be intensively grazed all over the year with sheep and goats which constitute the main livestock raised. The percentage of illiteracy among the respondents was found to be high (55.8%).