Nine samples of range herbage species were collected within the grazing season using 0.5 × 0.5 m quadrate as from three weeks initial pasture growth established in June across throughout up to December (two seasons), to examine the effects of age on the trend of some chemical compositions and energy changes. Analysis of variance indicated that the chemical composition of grassland from 3 weeks of age, to 12 weeks of age across to 27 weeks of age was affected by the grass age, where the metabolizable energy contents were 15.85, 13.11 and 12.36 MJ/Kg/DM respectively. Hemi-celluloses and cellulose content showed a significant difference increase (P < 0.05) throughout the grazing season as grass age increases. The results also revealed that the Organic Matter (OM), Crude Protein (CP) and Metabolizable Energy (ME MJ/Kg DM) were significantly (P < 0.05) tended to be high at the beginning of growing season (mid July) (91.05%, 3.8% and 8.77 MJ respectively), then increased towards the mid of grazing season (mid September) and reduced towards the end of the grazing season (mid December).
A major portion of grassland research and pasture development has taken place during the last 50 years to 20th century [
Grasslands provide a major portion of the livestock feed for the domestic and game animals. They furnish over one-half of the total feed supply in many countries and up to 85 and 95 percent in others [
Grassland in which grasses predominate still provides the basic feed requirements for growth and develop- ment of livestock particularly ruminants, their maintenance and the production of their products needs [
A majority of these grasslands are located in regions characterized by erratic rainfall patterns and varying pe- riods of extreme drought and often soils of poor fertility unsuited to cropping. Seasonal distribution of rainfall and soil conditions imposes a direct influence on the amount and quality of forage available during the year and indirectly affected animal performance [
Livestock production in the tropics can increase through increasing the output per animal and the productivity per unit area of land [
More than 15 million people worldwide are dependent on pastoral nomadism razing their Herds over some 67 million Km2, which is approximately twice the cultivated area in the world [
The experiment was conducted at Ghazal Gawazat Livestock and Range Research Station, South Darfur (Lati- tude 11˚28'N; Longitude 25˚57'E and altitude 485 m above sea level). The grazing season is divided into nine intervals (each of three weeks), as from the three weeks grass age (3 weeks), to twenty-seven (27 weeks) weeks of grass age (10th June-19th December 2004).
The total area of the station is 51.2 Km2 divided by fire-lines into twenty (20) equal grazing paddocks of 2.56 Km2 each, covering an area of about 5310 ha [
The range samples were collected from within the study site by manual clipping of enough amounts of grasses using the 0.5 × 0.5 m quadrate with scissors. The samples were clipped 5cms above the ground level according to [
The effect of advance range age on nutritive value in terms of dry matter (DM%), crude protein (CP%), crude fiber (CF%), nutrient detergent fiber(NDF%), acid detergent fiber (ADF%), cellulose and lignin decrease or in- crease was investigated. Also the trend in metabolizable energy content was calculated after [
As shown in
Grass Age in Weeks | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chemical Analysis | 3 | 6 | 9 | 12 | 15 | 18 | 21 | 24 | 27 | Overall Mean | SEM | LSD |
DM% | 80.58d | 82.04d | 84.00c | 90.23b | 92.30b | 96.19a | 91.47b | 91.10b | 91.87b | 88.65 | 1.01 | ** |
Ash% | 8.95e | 10.59d | 9.98e | 8.88e | 8.60e | 13.00b | 12.19c | 14.18a | 12.07c | 10.94 | 0.52 | * * |
OM% | 91.05a | 89.41a | 89.98a | 91.13a | 91.40a | 87.50c | 87.81c | 85.83e | 87.93b | 89.11 | 0.59 | * |
CP% | 3.89d | 4.06d | 7.90a | 8.80a | 8.60a | 6.91b | 5.21c | 5.08c | 4.08d | 6.06 | 0.27 | ** |
CF% | 21.25f | 19.38f | 22.53f | 34.47c | 34.71c | 38.79a | 36.05b | 32.86d | 28.96c | 29.85 | 0.71 | *** |
EE% | 6.63c | 5.05d | 5.95d | 7.86c | 4.28e | 3.96e | 5.17d | 10.18b | 12.90a | 6.88 | 0.41 | *** |
NFE% | 45.13a | 46.26a | 48.94b | 40.78c | 34.26e | 34.88c | 37.82d | 30.66e | 42.55b | 38.81 | 1.29 | *** |
NDF% | 52.30d | 59.95c | 61.79c | 66.59c | 69.60b | 73.53a | 53.82d | 53.60d | 56.65d | 60.09 | 0.93 | *** |
Hemi-Cellulose% | 8.62e | 27.32b | 26.17b | 34.44a | 28.60b | 22.88c | 19.69d | 15.29d | 9.25e | 21.31 | 2.42 | *** |
ADF% | 36.65d | 37.64d | 35.13d | 32.15e | 41.05c | 51.16a | 34.13d | 38.24d | 47.40b | 39.28 | 0.94 | *** |
Cellulose% | 26.28c | 24.00c | 25.88c | 24.00c | 36.71b | 86.04a | 16.97d | 16.18d | 12.55e | 23.73 | 1.48 | *** |
Lignin% | 7.81e | 8.31e | 8.26e | 8.15e | 9.34e | 15.12d | 17.16c | 22.06b | 34.85a | 15.45 | 0.52 | *** |
ME MJ/kg/DM | 15.85a | 12.87c | 12.25c | 13.11b | 12.02c | 9.57e | 11.06d | 12.99c | 12.36c | 12.45 | 0.56 | ** |
a, b, c, d, and e values on the same row with different superscripts differ significantly. SE = Standard Error. LSD = Least Significant Difference. * = Significant at (P < 0. 05). ** = Significant at (P < 0. 01). *** = Significant at (P < 0. 001). DM = Dry Matter, OM = Organic Matter, CP = Crude Protein, CF = Crude Fiber, EE = Ether Extract, NFE = Nitrogen Free Extract, NDF = Neutral Detergent Fiber, ADF = Acid Detergent Fiber, ME = Metabolizable Energy.
crude protein significantly (P < 0.05) was higher during the same time and tends to declines towards the end of the grazing season. On the other hand, crude fiber, neutral detergent fiber, and acid detergent fiber significantly (P < 0.001) higher towards the eighteen weeks of age than in the first three weeks of age. The metabolizable energy was significantly (P < 0.05) higher at the early grass age (3 weeks, 15.85 MJ/Kg) than in late grass age 27 weeks of age (12.36 MJ/Kg).
As shown also in
The chemical composition of range grassland is influenced by different factors such as grass age, soil type and remarkably the precipitation intensity or season [
Grass Age Intervals (Month) | |||||||||
---|---|---|---|---|---|---|---|---|---|
Nutrients | First July | Mid August | Mid September | Mid October | Mid November | Mid December | Overall Mean | SEM | LSD |
DM% | 80.58d | 84.00d | 90.23c | 96.19a | 91.47b | 91.87b | 88.65 | 1.01 | ** |
Ash% | 8.95d | 9.98c | 8.88d | 13.00a | 12.19b | 12.07b | 10.94 | 0.52 | * |
OM% | 91.05a | 89.98b | 91.13a | 87.50c | 87.81c | 87.93c | 89.11 | 0.59 | ** |
CP% | 3.82e | 7.90e | 8.80a | 6.91c | 5.21d | 4.03e | 6.06 | 0.27 | ** |
CF% | 21.25e | 22.53e | 34.17c | 38.79a | 36.05b | 28.96d | 29.85 | 0.71 | * |
EE% | 6.63a | 5.95e | 7.86a | 3.96d | 5.17c | 12.90 | 6.88 | 0.41 | * |
NFEE% | 45.13e | 43.94b | 40.78c | 34.88e | 37.82d | 42.55b | 38.81 | 1.29 | * |
NDF% | 45.34e | 61.79c | 66.59b | 73.53a | 58.84d | 56.65d | 60.09 | 0.39 | ** |
Hemi-Cellulose% | 8.62c | 26.17c | 34.44a | 22.32b | 19.69d | 9.25e | 21.31 | 2.42 | ** |
ADF% | 36.65c | 35.13c | 32.15d | 51.16a | 34.13d | 47.46b | 39.28 | 0.94 | * |
Cellulose% | 26.28b | 25.88b | 24.20c | 36.04a | 16.97d | 12.55e | 23.73 | 1.48 | * |
Lignin% | 7.81e | 8.26d | 8.15d | 15.82c | 17.16b | 34.85a | 15.45 | 0.52 | ** |
ME MJ/kg/DM | 8.85a | 8.11ab | 8.62b | 6.76c | 6.47d | 6.40d | 12.45 | 0.56 | ** |
a, b, c, d, and e values on the same row with different superscripts differ significantly. SE = Standard Error. LSD = Least Significant Difference. * = Significant at (P < 0. 05). ** = Significant (P < 0.01). DM = Dry Matter, OM = Organic Matter, CP = Crude Protein, CF = Crude Fiber, EE = Ether Extract, NFE = Nitrogen Free Extract, NDF = Neutral Detergent Fiber, ADF = Acid Detergent Fiber, ME = Metabolizable Energy.
Grass Age in Weeks | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chemical Analysis | 3 | 6 | 9 | 12 | 15 | 18 | 21 | 24 | 27 | Overall Mean | SEM | LSD |
DM% | 80.88c | 82.75c | 91.49cc | 90.77d | 9525b | 95.09b | 91.17d | 93.93c | 96.60a | 89.77 | 1.22 | ** |
Ash% | 13.15 | 11.91 | 11.06 | 11.63 | 9.17 | 12.23 | 10.72 | 12.19 | 13.03 | 11.73 | 0.99 | NS |
OM% | 86.85 | 88.09 | 88.64 | 87.38 | 89.29 | 87.78 | 89.29 | 87.81 | 86.67 | 88.42 | 0.68 | NS |
CP% | 5.05d | 5.05d | 7.72c | 8.09b | 9.58a | 7.28c | 5.08d | 3.75d | 4.49d | 6.21 | 0.48 | * |
CF% | 22.26d | 24.00d | 24.23d | 31.26c | 44.03a | 24.25d | 41.46b | 33.73c | 23.70d | 29.88 | 1.14 | *** |
EE% | 5.30c | 6..03b | 7.20a | 4.38d | 5.88c | 3.79d | 6.66c | 3.61d | 2.80c | 4.96 | 0.38 | * |
NFEE% | 37.26c | 34.18d | 34.35d | 37.70c | 48.25a | 38.26b | 38.80b | 37.80c | 49.83a | 39.60 | 1.07 | ** |
NDF% | 36.23c | 59.80b | 54.68c | 45.38d | 47.50d | 64.79a | 61.25b | 63.38a | 64.05a | 54.67 | 1.02 | *** |
Hemi-Cellulose% | 4.48f | 21.09b | 8.27f | 6.99f | 8.99f | 19.12c | 11.90c | 15.22d | 30.11a | 14.00 | 1.42 | *** |
ADF% | 31.75d | 38.72b | 46.36a | 38.39b | 35.81c | 46.67a | 49.35a | 45.66a | 33.94c | 40.74 | 1.48 | ** |
Cellulose% | 14.05d | 12.98d | 29.55a | 23.37b | 14.50d | 30.44a | 24.21b | 24.99b | 20.09c | 21.47 | 2.32 | ** |
Lignin% | 9.70e | 12.49c | 16.81d | 15.02d | 21.34c | 22.24c | 25.14b | 31.56a | 33.86a | 19.24 | 1.44 | ** |
ME MJ/kg/DM | 12.85b | 12.06b | 12.40b | 11.37c | 13.66a | 9.39d | 11.86c | 9.65d | 9.80d | 11.44 | 0.41 | * |
a, b, c, d, e, and f values on the same row with different superscripts differ significantly. SED = Standard Error. LSD = Least Significant Difference. NS = Not Significant, * = Significant at (P < 0.05). ** = Significant at (P < 0.01). *** = Significant at (P < 0.001). DM = Dry Matter, OM = Organic Matter, CP = Crude Protein, CF = Crude Fiber, EE = Ether Extract, NFE = Nitrogen Free Extract, NDF = Neutral Detergent Fiber, ADF = Acid Detergent Fiber, ME = Metaboliza- ble Energy.
Grass Age Intervals | |||||||||
---|---|---|---|---|---|---|---|---|---|
Chemical Composition | First July | Mid August | Mid September | Mid October | Mid November | Mid December | Overall Mean | SEM | LSD |
DM% | 80.88d | 89.49c | 90.77b | 95.09a | 91.17b | 96.60a | 89.77c | 1.22 | * |
Ash% | 13.45 | 11.06 | 11.63 | 12.23 | 10.72 | 13.03 | 11.73 | 0.99 | NS |
OM% | 86.85 | 88.64 | 89.38 | 87.78 | 89.29 | 86.67 | 88.42 | 069 | NS |
CP% | 5.05c | 7.72b | 8.09a | 7.28b | 5.08c | 4.40d | 6.21 | 0.48 | ** |
CF% | 22.26d | 24.22c | 31.26b | 24.25c | 41.46a | 23.70d | 29.88 | 1.14 | ** |
EE% | 5.30b | 7.20a | 4.33c | 3.39d | 5.66b | 2.80e | 4.96 | 0.38 | ** |
NFEE% | 37.26c | 34.35d | 37.70c | 38.26b | 38.80b | 49.33a | 39.60 | 1.07 | ** |
NDF% | 36.23e | 54.58c | 45.38d | 64.39a | 61.25b | 64.05a | 54.67 | 1.02 | ** |
Hemi-Cellulose% | 4.48f | 8.27d | 6.99e | 19.12b | 11.90c | 30.11a | 14.00 | 1.42 | * |
(ADF%) | 31.75e | 46.36b | 38.39c | 46.67b | 49.35a | 33.94d | 40.74 | 1.48 | ** |
Cellulose% | 14.05d | 29.55a | 23.37b | 30.44a | 24.21b | 20.07c | 21.47 | 2.32 | ** |
Lignin% | 9.70e | 16.81d | 15.02d | 22.24c | 25.14b | 33.86a | 19.34 | 1.41 | * |
ME MJ/kg/DM | 7.77b | 6.63c | 8.81a | 6.60c | 6.17c | 6.16c | 6.88 | 0.14 | * |
a, b, c, and d = Values on the same row with different superscripts differ significantly. SEM = Standard Error. LSD = Least Significant Difference. NS = Not Significant. * = Significant at (P < 0. 05). ** = Highly Significant (P < 0.001). DM = Dry Matter, OM = Organic Matter, CP = Crude Protein, CF = Crude Fiber, EE = Ether Extract, NFE = Nitrogen Free Extract, NDF = Neutral Detergent Fiber, ADF = Acid Detergent Fiber, ME = Metabolizable Energy.
Season | DM% | Ash % | OM% | CP% | CF% | EE% | NFEE % | NDF % | Hemi Cellulose % | ADF % | Cellulose % | Lignin % | ME MJ/kg/DM |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
2004 | 88.65b | 10.94b | 89.11a | NS 6.06 | NS 29.85 | 6.88a | NS 38.81 | 60.09a | 21.31a | 39.28b | 23.73a | 15.45b | 12.45a |
2005 | 89.77a | 11.73a | 88.42b | NS 6.21 | NS 29.88 | 4.96b | NS 39.60 | 54.67b | 14.00b | 40.74a | 21.47b | 19.24a | 11.44a |
Overall Mean | 89.21 | 11.34 | 88.77 | 6.13 | 29.87 | 5.92 | 39.20 | 57.39 | 17.66 | 40.00 | 22.60 | 17.35 | 11.95 |
SED | 1.580 | 1.12 | 0.90 | 0.56 | 1.42 | 0.56 | 1.63 | 1.38 | 2.81 | 1.75 | 2.58 | 1.50 | 0.69 |
Sign | * | ** | * | NS | NS | * | NS | * | * | * | * | * | NS |
a and b = Values on the same column with different superscripts differ significantly. SED = Standard Error Differences. * = Significant at P (<0.05). ** = Significant at (P < 0.01). NS = Not Significant. DM = Dry Matter, OM = Organic Matter, CP = Crude Protein, CF = Crude Fiber, EE = Ether Extract, NFE = Nitrogen Free Extract, NDF = Neutral Detergent Fiber, ADF = Acid Detergent Fiber, ME = Metabolizable Energy.
The variations in the nutritional value of these range herbage considerably differ within the season. From the first showers and rains, the grass sward is established and within the range of the first three weeks of age as from July throughout towards the end of the rainy or grazing season in October up to December (i.e. autumn and winter) varies. This seems to follow the natural or usual patterns under unimodel rainfall.
Most tropical and subtropical grassland have high nutritive value during the early growth, but their nutritive value declines rapidly with maturity [
The dry matter (DM) apparently in the two seasons tends to increase towards the mid of September until it reached its maximum level in mid October, when all plant growth was achieved at maturity. Neutral detergent fiber (NDF), follow the same level trend of increase as dry matter. This finding goes in line with that of [
The crude protein and lignin increase were significantly modified by the range grass age. The crude protein increase beings in early rains in July then starts to increase towards the mid September when it reached its high- est level when range herbage was well established due to sufficient amount of rainfall and excellent growth of all range species. Apparently the lignin also follows the trend level of increase of crude protein with the ad- vanced grass age but in less percentage. Moreover, the crude protein started to decline towards the mid of Octo- ber, through November and December while lignin level tends to a continued increase as range species ages in- crease towards the mid November and mid December. Similar trends were observed by [
Apparently the metabolizable energy, (ME MJ/KgDM) was significantly higher in mid September (8.80 MJ/Kg) than in mid October (6.76 MJ/Kg) and mid December (6.44 MJ/Kg). Also Hemicellulose and Neutral detergent fiber (NDF) in the present study were comparatively higher in season 2004 than in 2005, which could be attributed to rainfall fluctuation. Nitrogen Free Ether Extracts and Ash findings were accordance with [
It can be stipulated that despite the variations in rainfall, as they gain maturity, most grasses were expected to lose their high nutritive value they had during their early stages of growth [
In conclusion, as herbage age increase towards the end of the grazing season (rainy season), its nutritive value drastically declined in terms of crude protein (CP) and metabolizable energy (MJ) content. The age affected nu- tritional status of grasslands. Crude protein (4.03%) content decreased with the increased maturity stage of range grasses (27 weeks), accordingly the crude fiber (23.79%) also was depressed by age increase. This in terms was ascribed to increase in lignin content (34.85%). Also the nutritional status of the range site varies from season to season depending on the intensity of rainfall received. Therefore the animals have to graze in large areas before they can meet and satisfy their maintenance requirements.
This study was supported by University of Juba with the grant-in-aid from the former Directorate of Animal Resources Research Co-Operation, Sudan.