Effects of commonly used chemical fertilizers on development of free-living stages of Haemonchus contortus in experimentally infected pasture

AIM: The effects of N-P-K fertilizers in the form of urea, single super phosphate and muriate of potash on development of free-living stages of Haemonchus contortus were studied. MATERIALS AND METHODS: Five parasite free experimental plots of 1 m×1 m area, each of paddy leaves (15-day-old) and an equal number of Cynodon dactylon grass were infested with about 10×10(4) eggs/ml phosphate buffer saline along with the application of the calculated amount of fertilizers solution. On the 10(th) day of posttreatment, the pasture was cut, processed, larvae recovered by Baermann method and counted, which was expressed as number of L(3) per kg dry matter (DM) of pasture. RESULTS: The average recovered population of L(3) of H. contortus per kg DM varied significantly (p<0.05) between the paddy leaves (5933.57±22.718) and Cynodon grass (4861.00±22.718). When different doses of chemical fertilizer and their impact on different pasture were analyzed for control (T-1, 0-0-0 kg/ha N-P-K), the mean L(3) recovery per kg DM of paddy (19512.7±50.80) was more than that of Cynodon grass (16540.9±50.80). Larvae recovery per kg DM for different pastures under treatment were in decreasing order as follows: T-2 of paddy (6981.33±50.80, 35.77%), T-2 of Cynodon (5545.38±50.80, 33.52%), T-3 of paddy (317378±50.80, 16.26%), and T-3 of Cynodon (2218.72±50.80, 13.41%) which showed significant difference (p<0.05) among the treatments. In T-4 (paddy) and T-5 (Cynodon), the average number of recovery of larvae was nil implying no significant variation (p>0.05). CONCLUSION: This study shown that when N-P-K fertilizers administered at recommended level, significantly reduced larval translation of H. contortus minimizing pasture infectivity for the free range grazing animals.