Vachellia karroo is an important pasture legume which fixes nitrogen through its symbiotic relationship with rhizobia. Thirty two indigenous rhizobia were isolated from four different morphotypes of V. karroo obtained from four agro-ecologically diverse areas of South Africa. Phenotypic characterization of isolates revealed that they have the same colony morphology. Numeric analysis of the isolates&rsquo; phenotypic characteristics produced six clusters at 83% level of relative similarity. High variation of the isolates growth in different temperatures, salt concentration, pH, antibiotic resistance and heavy metal resistance was also noted. Carbon source utilization was generally the same for all isolates. Isolates that tolerated a wide range of test conditions are recommended as potentially highly competitive V. karroo inoculants for use in various climatic and soil conditions.

Phenotypic characterisation of rhizobia nodulating different&nbsp;morphotypes of Vachellia karroo

A study was conducted to determine preference intake and relative palatability indices of tanniniferous Acacia karroo fed to 5 growing male Pedi goats with an average body weight of 19.81 &plusmn; 1.83kg. Five feeding troughs were provided to each goat and each animal was exposed to all the experimental diets. A cafeteria feeding approach was used, thus, permitting goats free access to the diet of their choice. Acacia karroo (K) was offered in a mixture with Setaria verticillata (S) hay at five different levels: Diet 1: S80K20, Diet 2: S75K25, Diet 3: S70K30, Diet 4: S60K40 and Diet 5: S50K50. The daily relative palatability indexes (RPI) obtained for each diet were subjected to analysis of variance with feeds as treatments and individual animals as replicates in a completely randomized design. Significant differences (P Diet 4&gt; Diet 3&gt; Diet 2&gt; Diet 1. Diet 5 appeared to be the most preferred by goats with an RPI of 96.91%. Palatability indices were positively and significantly (Pand tannin contents. Results of this study indicated that tannin-rich Acacia karroo leaves when fed in a mixed diet could influence preference and intake by Pedi goats. Palatability studies could be used in designing supplemental feeding programs for ruminant livestock in the tropics.

Phenotypic characterisation of rhizobia nodulating different morphotypes of Vachellia karroo

Voluntary intake and palatability indices of pedi goats fed different levels of Acacia karroo leaf meal by cafeteria method