Estudio de las cargas de parásitos gastrointestinales de bovinos y búfalos faenados en el frigorífico de Gobernador Virasoro y su relación con la excreción de huevos por gramo de materia fecal y coprocultivo

Monitoring the fecal eggs count in faeces (EPG) of grazing animals is one of the ways to study the epidemiology of parasitic gastroenteritis in ruminants. In spite of this, the information obtained is limited because it doesn´t allow the recognition of parasitic species, and the big prolificacy of some of them prevents the visualization of other species. There isn´t a positive correlation between the EPG value and the true nematode burden in the host. Necropsy is the only technique to know this value. The objective of this study was to determine the number and combinations of adult specimens (AE) of each genera of gastrointestinal nematodes (GIN) present in the gastrointestinal tract (GI) of cattle and buffaloes over one year old slaughtered at Virasoro (Corrientes) slaughterhouse, and its relation with the EPG and the coprocultive. The study period ranged from March 2016 to April 2017, where the following techniques were performed: identification and quantification of GIN at necropsy, EPG by Modified McMaster technique (Robert and O’Sullivan, 1949) in faeces extracted from the rectum prior to slaughter, and identification of third stage larvae by coprocultive according to Niec, R. (1968). Nine parasitic necropsies were performed, 3 corresponded to buffaloes and 6 to bovines. One buffalo and three cattle didn´t present GIN and their EPG value was negative. The second buffalo presented 600 AE of Haemonchus spp and 600 AE of Trichostrongylus spp, with an EPG value of 10 and the coprocultive was negative. The third buffalo presented an abomasum burden of 1700 AE of Haemonchus spp, and EPG of 60, and larvae of Haemonchus spp were identified in the coprocultive. The fourth bovine presented 800 AE of Haemonchus spp and 100 AE of Trichostrongylus spp, with EPG negative. The fifth bovine presented in the abomasum 1200 AE of Haemonchus spp and 1700 AE of Trichostrongylus spp, and in the large intestine 300 Oesophagostomum spp, with a EPG of 160, being able to be identified in the coprocultive larvae of Haemonchus spp and Trichostrongylus spp. In the last bovine, 300 AE of Trichostrongylus spp were found in the abomasum and 100 in the small intestine of Cooperia spp, with a negative EPG. Low EPG counts don´t correlate with low GIN load values, since the immune response that the host develops may interfere with oviposition. Sampling will continue to be done to achieve de objectives originally proposed.