Antimicrobial usage and resistance in beef production

Antimicrobials are critical to contemporary high-intensity beef production. Many different antimicrobials are approved for beef cattle, and are used judiciously for animal welfare, and controversially, to promote growth and feed efficiency. Antimicrobial administration provides a powerful selective pressure that acts on the microbial community, selecting for resistance gene determinants and antimicrobial-resistant bacteria resident in the bovine flora. The bovine microbiota includes many harmless bacteria, but also opportunistic pathogens that may acquire and propagate resistance genes within the microbial community via horizontal gene transfer. Antimicrobial-resistant bovine pathogens can also complicate the prevention and treatment of infectious diseases in beef feedlots,threatening the efficiency of the beef production system. Likewise, the transmission of antimicrobial resistance genes to bovine-associated human pathogens is a potential public health concern. This review outlines current antimicrobial use practices pertaining to beef production, and explores the frequency of antimicrobial resistance in major bovine pathogens. The effect of antimicrobials on the composition of the bovine microbiota is examined, as are the effects on the beef production resistome. Antimicrobial resistance is further explored within the context of the wider beef production continuum, with emphasis on antimicrobial resistance genes in the food chain, and risk to the human population.

Feed profile analysis of oil palm‐integrated beef cattle farming systems by metabolic energy budgeting and implications for beef production and pastoral system design

Background:Oil palm is a tropical crop with worldwide plantings approaching 20 million ha and large areas in Indonesia,Malaysia and Thailand.The plantations are readily managed as silvopastoral systems incorporating cattle grazing(Oil Palm Silvopastoral System for Cattle,OPSC)but there is a need for analytical tools and data to understand system herbage supply and feed conversion efficiency(FCE).Methods:Metabolic energy budgeting was used to estimate herbage harvested by cattle in three OPSC subsystems,9 and 12 years after oil palm establishment,and FCE of the subsystems was determined.Understorey herbage was also analysed for nutritive value,botanical composition and herbage accumulation within one grazing‐regrowth cycle.Results:The herbage‐harvested estimate was 2.0−2.4 t dry matter(DM)ha^(-1) year^(-1) for 9 year old subsystems and 1.4-1.7 tDMha^(-1) year^(-1) for a 12 year old subsystem.Herbage metabolisable energy(ME)was 8.3−8.5 MJ kg^(-1) DM and crude protein(CP)was 15%-16%DM.FCE values for subsystems ranged from 32 to 94 kg DM kg^(-1) liveweight‐gain.Conclusions:Herbage DM yield is declining,while herbage ME is marginal but CP is adequate.FCE is suboptimal but can be optimised by defining the trajectory of declining herbage production with canopy closure as plantations age and matching stocking rate to herbage supply using a comparativestocking‐rate‐type statistic.

Application of Geographic Information Systems in Studying the Relationship between Stock Routes Changes with Water and Pasture Availability for Livestock under a Changing Climate Conditions： A Case of Ilemela and Magu Districts in Mwanza Region-Lake Victoria Basin, Tanzania

Beef cattle production is declining in the areas surrounding LVB （Lake Victoria Basin） due to many factors among which is the climate change. This study was focused on generating spatial knowledge that will be useful in designing appropriate strategies for improving beef cattle production on rangelands of the LVB, through assessing changes in stock routes in relation to water and pasture availability for livestock under a changing climate. The study used participatory mapping and focused group discussions to assess spatial changes of stock routes in relation to water availability and pasture under critical climate changes. Also, GIS （Geographic Information Systems） technologies were deployed in formalization of spatial layers for integration with other pertinent datasets to the facilitate analysis. The study revealed remarkable stock routes changes （i.e. some have been lost, some have been converted into roads, while others have been lost and others narrowed influencing conflicts between pastorists and farmers. The stock routes changes are made by the increased human population which has led to an increase of cultivated areas and subsequently the decline of water sources and grazing land for pastorists. It is recommended that there should be effective land use planning practice, real-time stock route modification concomitant with adverse climate changes and cattle farming practice. Intervention by other mitigation measures particuticularly rainwater harvesting which is a strategy for alleviation of climate change effects for improving beef cattle production in LVB areas is proposed.