Comparative susceptibility and pathogeny of Nelore and Holstein-Friesian calves to the experimental infection of Haemonchus placei (Place, 1893)

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2014-02-26T17:08:46Z No. of bitstreams: 1 WOSA1997XU89300002.pdf: 5140955 bytes, checksum: e3de0a1ec4398f43a0f098820ed9046b (MD5) Made available in DSpace on 2014-02-26T17:08:46Z (GMT). No. of bitstreams: 1 WOSA1997XU89300002.pdf: 5140955 bytes, checksum: e3de0a1ec4398f43a0f098820ed9046b (MD5) Previous issue date: 1997-06-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:22:10Z No. of bitstreams: 1 WOSA1997XU89300002.pdf: 5140955 bytes, checksum: e3de0a1ec4398f43a0f098820ed9046b (MD5) Made available in DSpace on 2014-05-20T15:22:10Z (GMT). No. of bitstreams: 1 WOSA1997XU89300002.pdf: 5140955 bytes, checksum: e3de0a1ec4398f43a0f098820ed9046b (MD5) Previous issue date: 1997-06-01 Two groups of Holstein-Friesian and Nelore calves, five animals each, about nine months old, received, by oral route, 1,000 infective larvae (L-3) per kg of body weight of Haemonchus placei. Blood samples were collected by venipuncture, at weekly intervals, from one week before, to eight weeks after infection. Hematological studies comprised the hematocrit, differential leukocyte counts, hemoglobin, fibrinogen and plasma protein determinations. Parasitological examinations covered weekly fecal egg counts (EPG) and worm burden counts at necropsy. Samples of the abomasal mucosa were submitted to gross examination and histopathological studies. Both groups had increasing EPG after the fifth week, with Holstein calves showing higher counts than the Nelore. Holstein calves had anemia and hipoproteinemia from the third week post-infection to the end of the experiment, whereas Nelore calves showed no significant differences in those, parameters. Holstein calves had significantly larger worm counts than the Nelore. The gross and histopathological lesions in the abomasum at necropsy were very similar, although macroscopically they look more apparent in the Holstein group. These results showed that Holstein calves are more susceptible to the infection and pathogenic effects of H. placei than Nelore calves. UNIV ESTADUAL PAULISTA JULIO MESQUITA FILHO,FMVZ,DEPT CLIN VET,CAIXA POSTAL 560,BR-18618000 BOTUCATU,SP,BRAZIL UNIV ESTADUAL PAULISTA JULIO MESQUITA FILHO,FMVZ,DEPT CLIN VET,CAIXA POSTAL 560,BR-18618000 BOTUCATU,SP,BRAZIL