Antibacterial activity of medicinal plants on the management of mastitis in dairy cows: A systematic review.

BACKGROUND: Mastitis is a disease of economic importance in dairy production systems. The common management regime for mastitis is the use of synthetic antibiotics, giving a new problem of antibiotic resistance. There is, therefore, a need to prospect for alternatives to conventional antibiotics from herbal plants. OBJECTIVES: This systematic review evaluates the use of plants as alternatives for the control of mastitis in dairy cattle, focussing on the effectiveness of studied plants and plant-based products and possible implications on the use of these products in livestock health. METHODOLOGY: The PRISMA model was implemented with searches done in five electronic databases: Scopus, ScienceDirect, PubMed, Ovid and Research4Life. Data were extracted from 45 studies with 112 plant species from plant species belonging to 42 different families. The specific keywords were 'mastitis', 'dairy cows' and 'medicinal plants'. RESULTS: The most cited plant species included Allium sativum L., Azadirachta indica and Eucalyptus globulus Labill with the latter further exploring its components. Microbial species causing mastitis mainly were Staphylococcus aureus and Escherichia coli. The extraction methods used included maceration approach using ethanol, methanol and water as solvents for phytochemicals and chromatographic techniques for essential oils. A few studies explored the mode of action, and toxicities of the herbal extracts as well as evaluating their efficacy in clinical trials using animal models. CONCLUSION: Plants with defined levels of phytochemicals were essential sources of antibacterials. Standardisation of analytical methods is required.

Phenotypic and genetic characterisation revealed the existence of several biotypes within the Neorautanenia brachypus (Harms) C.A. wild accessions in South East Lowveld, Zimbabwe.

BACKGROUND: Local communities in the South Eastern Lowveld of Zimbabwe have adopted the feeding of livestock with Neorautanenia brachypus (Harms) C.A. tuber to mitigate against climate change. Differences within Neorautanenia brachypus (Harms) tuber flesh colour and preferences by cattle have been observed, suggesting possible diversity within the N. brachypus plant community. This study aimed at distinguishing the N. brachypus wild plant species through phenotypic and genetic characterization using morphological descriptors and random amplified polymorphic (RAPD) markers respectively. Leaf samples were selected using judgmental sampling techniques from wards 11-15 in Sengwe (Chiredzi district) for leaf morphology and molecular characterization. RAPD-PCR analysis was done using 18-screened random decamer primers to confirm the diversity in the plant population. The similarity of the biotypes was evaluated using binary coding on the basis of the presence or absence of a morphological indicator as well as distinct DNA amplicon fragments. Primer 7.0.13 was used to estimate morphological and genetic similarities using the unweighted pair group method with arithmetic average (UPGMA). The cluster number was estimated using the Elbow method part of the R package. RESULTS: Initially, 14 biotype groups were identified from 96 accessions visually characterized basing of leaf characteristics. All the leaf biotypes displayed arcuate venation with differences observed for leaf shape, tip shape and leaf margins. The 14 biotypes clustered into six groups based on the binary data of the morphological characteristics. RAPD primers generated three hundred and sixty eight distinct amplicons with 77.5% being polymorphic from the 14 biotypes. The number of bands produced per primer ranged from four (OPF-02) to 44 (UBC-746). The PIC value ranged from 0.1327 to 0.1873 for the RAPD primers. Use of molecular markers collapsed the biotypes into five clusters. Both the leaf descriptors and RAPD markers showed the existence of genetic diversity within the wild accessions of N. brachypus. CONCLUSIONS: A combination of morphological and RAPD markers effectively refined the resolution of the genetic diversity within the N. brachypus wild accessions to nine biotypes. These findings have indicated to the existence of more than one biotype of N. brachypus with potentially different properties. The favorable biotypes can further be promoted through incorporation in pastures as alternative feed or complementary feed to livestock. As such the output of this study will serve as a guide for N. brachypus germplasm management and improvement.