Effect of Drinking Water Distribution System Design on Antimicrobial Delivery to Pigs

Drinking Pipes and Nipple Drinkers in Pig Abattoir Lairage Pens-A Source of Zoonotic Pathogens as a Hazard to Meat Safety

The water distribution system in the lairage pens of abattoirs could act as a route of contamination for produced meat. In this study, biofilm formation and the occurrence of specific pathogens in drinking equipment was investigated in different lairage pens in a German commercial pig abattoir. Samples of the water and the drinkers in different locations were microbiologically cultivated and examined. After new drinking equipment had been installed for one month, three months and five years, biofilm formation was detectable, and retrograde growth from the nipple drinkers was seen up to the connection with the main water distribution system. In particular, Enterobacteriaceae and Pseudomonas spp. were found in all samplings of the nipple drinkers. Zoonotic pathogens, Salmonella, pathogenic Yersinia enterocolitica and methicillin-resistant Staphylococcus aureus, were also isolated from the nipple drinkers, while Listeria monocytogenes was not detected via microbial cultivation methods in any of the samples. Since the pigs take the contaminated nipple drinkers into their mouths to drink, or drink contaminated water containing the pathogens, transmission and even infection of the pigs in the lairage can be assumed. This could consequently lead to contamination or cross-contamination of the meat during slaughter and processing and to a public health risk.

Qualitative risk assessment of homogeneity, stability, and residual concentrations of antimicrobials in medicated feed and drinking water in pig rearing

BACKGROUND

Despite the common use of oral group treatment in pig rearing, the magnitude of the factors influencing the homogeneity and stability of antimicrobial drugs in medicated feed and medicated drinking water are largely unknown, as well as the residual concentrations of the drugs after the end of the treatment.

RESULTS

This study presents a qualitative risk assessment to estimate the magnitude of the risks for reduced homogeneity and stability, and increased residual concentrations of antimicrobial drugs in medicated feed and drinking water on the farm. Risk assessment was done using a questionnaire and farm visits (n = 52), combined with a second questionnaire, and concentrations of amoxicillin and doxycycline measured in medicated feed and water samples, each collected on 10 farms. For medicated feed, the duration of storage in the silo did not show to influence the concentration levels in a consistent trend, while the treatment duration had a low to negligible effect. A moderate to high risk was found caused by human error when preparing the medicated feed on the farm. Purchased medicated feed greatly reduces the risk of human error and drugs remain stable during the duration of treatment, while the risk of residual concentrations after the end of the treatment was estimated to be low to moderate. The feed intake variability was identified as a moderate to high risk factor. For medicated drinking water, the type of dosing pump, age of pre-solution, and human errors during the preparation of the pre-solution present a moderate to high risk on homogeneity and stability. Precipitation of the active substance in the absence of a stirrer in a drinking water tank was shown to be a low to moderate risk factor for residues after treatment. Waterline length had a weak correlation with the concentrations of the antimicrobials, while a moderate to high influence was detected for the water intake by the pigs.

CONCLUSIONS

A considerable variation in drug concentration in both medicated feed and medicated drinking water was detected depending on their preparation. Therefore, it is important to know which factors influence the homogeneity and stability, and the residual concentrations after treatment.

Water use patterns within each day: Variation between batches of growing pigs in commercial production systems

Objective: To measure, describe, and compare the water use patterns within each day for multiple cohorts of weaner, grower, and finisher pigs in farm buildings. Materials and methods: Prospective, observational cohort studies of the water use patterns within each day were conducted in 5 pig buildings using either a turbine or ultrasonic water flow meter attached to the main water pipe entering each building. Water use data were collected from multiple batches of pigs (second-stage weaners over eleven 48-day periods and grower-finishers over 4 periods of 21-43 days). Semi-parametric models of pig water use patterns within each day were estimated using the brms software package in R. To estimate the interacting effects of time and pig body weight on water use by pigs, we used tensor product smooths for time and pig body weight. Results: The water use pattern within each day varied between the cohorts, and the pattern of many cohorts changed as the pigs gained weight. Some patterns were unimodal and others were bimodal, with the main peak in water use occurring early afternoon to late afternoon. Implications: Water use patterns of pigs within each day varied between and within cohorts. The water use pattern of one cohort cannot be used reliably to predict that of other cohorts, even if they are reared in the same building. Water use pattern data may be valuable for optimizing in-water antimicrobial dosing regimens.

Water consumption and wastage behaviour in pigs: implications for antimicrobial administration and stewardship

Daily water use and wastage patterns of pigs have major effects on the efficacy of in-water antimicrobial dosing events when conducted for metaphylaxis or to treat clinical disease. However, daily water use and wastage patterns of pigs are not routinely quantified on farms and are not well understood. We conducted a prospective, observational 27-day study of the daily water use and wastage patterns of a pen group of 15 finisher pigs reared in a farm building. We found that the group of pigs wasted a median of 36.5% of the water used per day. We developed models of the patterns of water used and wasted by pigs over each 24-h period using a Bayesian statistical method with the brm() function in the brms package. Both patterns were uni-modal, peaking at 1400-1700, and closely aligned. Wastage was slightly greater during hours of higher water use. We have shown that it is feasible to quantify the water use and wastage patterns of pigs in farm buildings using a system that records and aggregates data, and analyses them using hierarchical generalised additive models. This system could support more efficacious in-water antimicrobial dosing on farms, and better antimicrobial stewardship, by helping to reduce the quantities of antimicrobials used and disseminated into the environment.

Water Distribution Systems in Pig Farm Buildings: Critical Elements of Design and Management

Drinking water distribution systems (WDSs) within buildings on pig farms have critical elements of their design and management that impact water provision to pigs, water quality, the efficacy of in-water antimicrobial dosing, and, thus, pig health and performance. We used a mixed-methods approach to survey managers of 25 medium to large single-site and multi-site pig farming enterprises across eastern and southern Australia. We found wide variation in the configuration (looped or branched) and total length of WDSs within buildings across farms and in pipe materials and diameters. Within many conventional buildings and some eco-shelters, WDSs were 'over-sized', comprising large-diameter main pipelines with high holding volumes, resulting in slow velocity water flows through sections of a WDS's main pipeline. In over half of the weaner buildings and one-third of grower/finisher buildings, the number of pigs per drinker exceeded the recommended maximum. Few farms measured flow rates from drinkers quantitatively. WDS sanitization was not practiced on many farms, and few managers were aware of the risks to water quality and pig health. We identified important aspects of water provision to pigs for which valuable recommendations could be added to industry guidelines available to pig farm managers.