Consumption of antimicrobials for use in food-producing animals in New Zealand, a measure of progress in reduction from 2015 to 2022.

Aims: To describe progress in the reduction of the consumption of antimicrobial drugs by food-producing animals in New Zealand to 2022 and to identify the animal production sectors where progress has been greatest, and those where opportunities remain.

Methods: Data were sourced from official government and industry reports to update previous estimates of consumption (as sales) of antimicrobial products applied to food-producing animals in New Zealand, European countries and the USA. Antimicrobial consumption (AMC) was estimated based on the amount of active ingredient sold, per kg of animal biomass standardised to the probable weight at time of treatment or lifetime mean weight but not slaughter weight (population correction unit; PCU).

A retrospective on claims regarding clinical mastitis in the subsequent lactation, after use of an internal teat sealant in the dry period.

Infusion of an internal teat sealant into the mammary gland of the dairy cow at drying off has been claimed to reduce the incidence of clinical mastitis over many months in the subsequent lactation, despite the absence of any ingredient of the sealant remaining for that long. However, these claims have been poorly substantiated, often by lack of identification on when the infection occurred in the period from calving to disease, if the infection was present at post calving sampling and if the pathogen causing the disease was that causing an earlier infection. Moreover, no hypothesis on how any effect on clinical mastitis might occur has been advanced in any of the publications claiming the effect.

Use of antimicrobials for food animals in New Zealand: updated estimates to identify a baseline to measure targeted reductions.

Aim: To describe the use of antimicrobial drugs for food animals in New Zealand, based on sales data reported to government for 2005-2018, to provide a baseline to determine the success of measures to reduce antimicrobial use for food animals and to compare usage to selected European countries.

Methods: Data were sourced from official government and industry reports to update previous estimates of use (as amount sold) of antimicrobial products applied to animals in New Zealand. The data included antimicrobial sales and animal populations, weighted where appropriate by breed and age class.

Timing of entry of into the mammary gland of the dairy cow.

Streptococcus uberis do not colonise the teat canal and appear to invade the mammary gland of the dairy cow by direct entry though the canal. When they enter the mammary gland, and the early resulting processes, are unclear. Experimental infusions of the lactating mammary gland have been made to determine outcomes of infection, mastitis and disease.

Identification of an immune modulation locus utilising a bovine mammary gland infection challenge model.

Inflammation of the mammary gland following bacterial infection, commonly known as mastitis, affects all mammalian species. Although the aetiology and epidemiology of mastitis in the dairy cow are well described, the genetic factors mediating resistance to mammary gland infection are not well known, due in part to the difficulty in obtaining robust phenotypic information from sufficiently large numbers of individuals. To address this problem, an experimental mammary gland infection experiment was undertaken, using a Friesian-Jersey cross breed F2 herd.