ASSOCIATIONS BETWEEN DRINKING-WATER NITRATE AND THE PRODUCTIVITY AND HEALTH OF FARROWING SWINE

The associations between nitrate contained in drinking water and farro wing swine health and productivity were examined, The study was conduc ted from November 1989 through February 1991 on 571 randomly selected swine farms (27 207 farrowing swine) in the United States, At the begi nning and end of each farm's 3-month monitoring period, the drinking w ater provided to the fan;owing swine was tested for nitrate. Data on f arrowing swine health and productivity were observed and recorded dail y by the animal caretaker. Data were analyzed on a farm basis, Nitrate was detected in 53.2% (304/571) of well-water samples, with a median concentration of 2.1 ppm. No association was seen between the nitrate concentration of drinking water and the farm litter size (P=0.94), pro portion of the pigs stillborn (P=0.48), or the risk of having an above median percentage of the litter born mummified (OR=1.0; 95% CI 0.99, 1.00). No association was seen between nitrate and the health of farro wing swine as measured by the risk of having an above median percentag e of farrowing swine ill (OR = 1.0; 95% Cl 0.99, 1.00) or dead ( OR = 0.99; 95% Cl 0.98, 1.01) due to farrowing problems, other reproductive problems (ill OR = 1.0, 95% CI 1.00, 1.01; dead OR = 1.0, 95% CI 0.98 , 1.01), other known health problems (ill OR = 1.0, 95% CI 0.99, 1.00; dead OR = 1.0, 95% CI 0.99, 1.01), or unknown health problems (ill OR = 1.0, 95% CI 0.99, 1.01; dead OR = 1.0, 95% CI 0.99, 1.01). The resu lts of this study indicate that nitrate contained in drinking water, a t the concentrations seen during the National Swine Study, is not asso ciated with the farrowing swine health or productivity parameters stud ied.