Effects of grazing at different stocking densities and grazing period on yield and chemical composition of herbage in the subhumid zone of Nigeria
Iji, P.A. | Tarawali, G. | Umunna, N.N. | Alawa, J.P. (Ahmadu Bello Univ., Zaria (Nigeria). Dept. of Animal Science)
Over a grazing period of about 14 weeks, comparisons were made between pasture improved with Stylosanthes hamata and that based on natural grassland. The grazing densities ranged from 2.11 to 4.23 TLU/ha (Tropical Livestock Unit = 250 kg liveweight). Both pastures were grazed in the previous wet season by West African Dwarf goats at similar grazing densities. Dry matter yields varied significantly (P0.01) by period of grazing season but not so much by grazing density. Organic matter and crude protein contents varied significantly (P0.01) by period of grazing season but not so much by grazing density. Organic matter and crude protein contents varied significantly (P0.001) during the season and were higher (P0.01) on improved pasture. Neutral detergent fibre content was higher (P0.05) at the low stocking density and was also dependent on season. Calcium and phosphorus contents were similar in herbage from both pastures while magnesium content was significantly (P0.05) higher on improved than unimproved pastures. The standing hay at the end of wet season was low in nutrients. Biomass production and quality of pastures improved with S. hamata would be adequate for wet season grazing although phosphorus supplementation may be required.
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