Effects of feeding zearalenone to sows on rebreeding and pregnancy.

Two trials were conducted with a total of 91 lactating sows fed 0, 5 or 10 ppm dietary zearalenone (Z) and 0 or 15% dietary alfalfa in a factorial arrangement to evaluate their influence on reproductive performance to 40 d postbreeding. Feeding of Z did not alter the proportion of sows returning to estrus; however, the weaning-to-estrus interval increased when increased dietary Z was fed in Trial 2, with a similar trend at the highest level in Trial 1. The average number of fetuses per sow with fetuses tended to decrease (P less than .05) with increasing dietary Z in Trial 2, but not in Trial 1. Embryonic mortality did not appear to increase when the ratio of fetuses to corpora lutea was compared in sows with fetuses in Trial 1, but it did increase in Trial 2. The trend to increased numbers of bred sows that were non-pregnant at slaughter when dietary Z increased in Trial 1 was not observed in Trial 2. Dietary dehydrated alfalfa meal did not appear to modify the effects of Z in these trials.