The utilization by domestic ruminants in Botswana of treatment diets containing cereal crop stovers treated with urea or urea and molasses

[摘要] English: The studies were aimed at examining the effects of treatment with urea or urea and molasseson the physical and chemical composition of stovers of sorghum, maize and millet andassessing the potential of these treated cereal crop stovers as additional feed for domesticruminants in Botswana. The trials were carried out at Sebele, Botswana College ofAgriculture (BCA), Botswana. Sebele is situated at 24º 33'S and 25º 57'E and is at an altitudeof 994 m above sea level. Cereal crop stovers were ground in a hammer mill and treated with10 g urea/kg stover (T1), 25 g urea/kg stover (T2) or 10 g urea + 10 g molasses/kg stover(T3) for 3 weeks. The experimental design for the treatment of the cereal crop stovers was a 3x 4 completely randomized factorial design [3 cereal crop stovers and 3 treatment methods(T1, T2, T3) plus untreated]. Samples of cereal crop stovers untreated or treated with T1, T2or T3 were obtained and analysed for dry matter (DM), organic matter (OM), crude protein(CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL)and in vitro DM digestibility (IVDMD). The physical changes on the cereal crop stovers dueto treatments were noted. Six steers, four of which were fitted with rumen cannulae, and sixgoats and six sheep were used in a crossover experiment to evaluate the utilisation oftreatment diets containing stovers of sorghum, maize and millet treated with T1, T2 or T3.The animals were kept in individual pens and fed a basal diet of veld grass hay plus acommercially available feed, namely Pen-feed. Each animal had unrestricted access to water and a mineral lick and were adapted to the respective treatment diets for 14 days, followed by7-day sampling periods The data collected included the feed intake and digestibilitycoefficients of DM, OM, CP, NDF and ADF. Data were also obtained on metabolisableenergy (ME) intake, average daily gains and the pH and ammonia concentration of rumenfluid.Treatment with T1, T2 and T3 increased the CP, NDF, ADF, ADL and IVDMD of the cerealcrop stovers. The mean CP (g/kg DM) of cereal crop stovers increased from 69.75 (untreated)to 99.94, 112.63, and 110.50 when treated with T1, T2 and T3 respectively. Significantimprovements in the total intake of DM and CP by steers compared to the Control diet wereobserved when feeding cereal crop stovers treated with T2 and T3. The improvements in theintake and nutrient digestibility coefficients when providing some treatment diets containingthe treated stovers are comparable to those obtained when offering lucerne hay which impliesthat these treatment diets may be suitable replacements for lucerne hay. However, thetreatment diets did not significantly improve the average daily gain and metabolic bodyweights of the steers, goats and sheep. Therefore, treatment diets containing stovers ofsorghum, maize or millet treated with T1, T2 or T3 used in the present study arerecommended for maintenance rather than production purposes.

[发布机构] University of the Free State