THE ALKAUNIZATION OF AMERICAN ALOE: LUCERNE FEED MIXTURES WITH CALCIUM HYDROXICE (SLAKED LIME)
B.R. KING & J.H. HOON
GROOTFONTEIN AGRICULTURAL DEVELOPMENT INSTITUTE MIDDELBURG 5900
American aloe (Garingboom) originates form South America and has been utilized as a drought fodder for sheep, cattle and ostriches. The low pH of American aloe (4.86 ± 0.06) gives rise to acidosis in sheep which is followed by lameness. Furthermore the low pH leads to the permanent destruction of the sellulolytic bacteria population in the rumen. To overcome these problems, it is standard practice to add slaked lime (Ca(OH)2) to chopped American aloe. This study was carried out to determine the optimum amount of Ca(OH)2 to be added to rations containing different ratios of American aloe and lucerne. Rumenfistulated Dorper ewes received a ration of either 60% American aloe: 40% lucerne (ration A) or 45% American aloe: 55% lucerne (ration B). Both rations were supplemented in ; succession with 0%, 0.5% or 1% (Ca(OH)2 for a one week period. At the end of each seven day period, the rumen pH was determined two hourly for a 12 hour period, starting prior to feeding the daily ration. When not supplemented with Ca(OH)2 the feeding of ration A led to a considerable drop in rumen pH to below 6. At the 0.5% and 1% inclusion of Ca(OH)2. the rumen pH dropped to a minimum of 6.3 after feeding and this was followed by a increase to 6.8 and 7.2 respectively. There was no significant difference in rumen pH in animals receiving ration B when containing the different Ca(OH)2 concentrations. These results indicate that the rumen is capable of controlling the pH when the ration contains 60% or more American aloe, it is essential to add between 0.5 and 1 % Ca(OH)2 to prevent the rumen pH dropping to unacceptably low levels.
SASAT Congress 1993