Browsing by Author "Kariuki, J.N"

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    Effect of age of improved forage sorghum on prussic acid toxicity and nutritive value to young ruminants in semi-arid Kenya
    (Chuka University, 2016) Irungu, R.; Ashiono, G.B.; Muasya, T.K.; Kariuki, J.N
    Sorghum (Sorghum bicolour (L.) Moench) is suitable fodder to alleviate feed shortage in semi-arid tropics as it is drought tolerant. Two varieties of forage sorghum were studied to ascertain the effect of age on prussic acid concentration and nutritive value and to establish the threshold at which it would be safe to feed the sorghum to young ruminants. Varieties E1291 and E6518, planted in randomized complete block layout with three replicates, were sampled for prussic acid (hydrocyanic acid, HCN) and nutrient composition at 5 and 10 weeks (first and second weeding and thinning) and thereafter, every 2 weeks up to 22 weeks. The data was subjected to analysis of variance and regression which showed that HCN negatively correlated to sorghum age. Variety E1291 contained less prussic acid compared to E6518. During the study, E6518 and E1291 contained 186.7 and 90.8; 167.5 and 139.8 mg/kg DM, HCN at 5 and 10 weeks, respectively, which decreased significantly to 81.6 and 70.8 mg/kg DM at 14 weeks. Prussic acid concentration in E1291 during the whole study period did not surpass the threshold of 200 mg/kg DM but the concentration in E6518 approached this threshold below 10 weeks’ growth. After 10 weeks’ growth E6518 also did not surpass the toxic threshold. Therefore, E1291 can be fed to young ruminants at any age but E6518 can only be fed after 10 weeks without toxic effects on young ruminants. Dry matter (DM), organic matter and fibre increased whereas crude protein decreased with sorghum age. The sorghum sampled young produced highly nutritious feed for young ruminants. However, the low DM is disadvantageous as ruminants offered these sorghum varieties ingest less DM compared to sorghum containing higher DM. Hence sorghum should be harvested later than 22 weeks of growth for higher DM intake by young ruminants.