title: Water-flow variation and pharmacoepidemiology of tetracycline hydrochloride administration via drinking water in swine finishing farms.
abstract: OBJECTIVE
  To evaluate variation of drinking-water flow rates in swine finishing barns and the relationship between drinker flow rate and plasma tetracycline concentrations in pigs housed in different pens.
  
  
  METHODS
  Cross-sectional (phase 1) and cohort (phase 2) studies.
  
  
  METHODS
  13 swine finishing farms (100 barns with 7,122 drinkers) in phase 1 and 100 finishing-stage pigs on 2 finishing farms (1 barn/farm) in phase 2.
  
  
  METHODS
  In phase 1, farms were evaluated for water-flow variation, taking into account the following variables: position of drinkers within the barn, type of drinker (swing or mounted), pig medication status, existence of designated sick pen, and existence of leakage from the waterline. In phase 2, blood samples were collected from 50 pigs/barn (40 healthy and 10 sick pigs) in 2 farms at 0, 4, 8, 24, 48, and 72 hours after initiation of water-administered tetracycline HCl (estimated dosage, 22 mg/kg [10 mg/lb]). Plasma tetracycline concentrations were measured via ultraperformance liquid chromatography.
  
  
  RESULTS
  Mean farm drinker flow rates ranged from 1.44 to 2.77 L/min. Significant differences in flow rates existed according to drinker type and whether tetracycline was included in the water. Mean drinker flow rates and plasma tetracycline concentrations were significantly different between the 2 farms but were not different between healthy and sick pigs. The plasma tetracycline concentrations were typically < 0.3 microg/mL.
  
  
  CONCLUSIONS
  Many factors affected drinker flow rates and therefore the amount of medication pigs might have received. Medication of pigs with tetracycline through water as performed in this study had questionable therapeutic value.
authors: Research and Development, Merial Limited, Duluth, GA 30096, USA.
authors: Paul M
authors: PM
authors: Dorr
authors: Megan S
authors: MS
authors: Nemechek
authors: Alan B
authors: AB
authors: Scheidt
authors: Ronald E
authors: RE
authors: Baynes
authors: Wondwossen A
authors: WA
authors: Gebreyes
authors: Glen W
authors: GW
authors: Almond
mesh_terms: D000822:Animal Husbandry / Q000295:instrumentation* / Q000379:methods; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004326:Drinking / Q000502:physiology; D004327:Drinking Behavior; D013552:Swine / Q000097:blood / Q000502:physiology*; D013752:Tetracycline / Q000008:administration & dosage* / Q000097:blood; D014867:Water / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D014867:Water; D013752:Tetracycline