José Luiz D'Angelino

Productive and reproductive performance in cattle infected with bovine leukosis virus

Economic losses caused by enzootic bovine leukosis (EBL) have been of interest since World War II, when the neoplastic form of EBL increased dramatically in Europe. Olson (1974) and House et al . (1975) showed that animals with lymphosarcoma caused by the bovine leukosis virus (BLV) had reduced milk yields, a less efficient reproductive performance and high veterinary costs and mortality rates, while many carcasses were rejected at slaughter. However, the actual impact of BLV infection in cattle without lymphosarcoma is not clear. The purpose of the study reported here was to compare some productive and reproductive responses of cattle that were antibody-positive (BLV+) or negative (BLV−) for BLV. Holstein dairy cows in commercial dairy farms were used in this study. Blood samples were collected and subjected to BLV serological examination by the agar gel immunodiffusion test of Miller & van der Maaten (1976). Animals were then grouped as BLV+ or BLV− according to their serological response to the BLV antigen. Productive and reproductive histories were obtained from individual animal records and the following factors were considered: milk production, calving interval and birth rate. For milk production, we had the daily milk yields of 547 animals, and for calving interval the time between two successive parturitions for 444 cows. These values were examined by ANOVA and when this was significant a Students t test was carried out for each age group. Birth rates, the percentage of animals that calved in 1 year, were available for 557 animals and were examined with the Z-two proportion test. For all analyses, P <0·05 was considered significant.

Chromosome aberrations in cattle raised on bracken fern pasture

Thirteen cows maintained on natural bracken fern (Pteridium aquilinum) were analyzed cytogenetically. The frequency of structural chromosome aberrations detected in peripheral blood cells was significantly higher when compared to that detected in animals raised on pasture containing no bracken fern. We discuss the clastogenic action of fern and its synergistic action with infection by type 2 and 4 papilloma virus in the same animals.

Epidemiological study of enzootic bovine leukosis in Brazil.

Enzootic bovine leukosis has been known in Brazil since 1943 when it was described by Rangel and Machado and is widely distributed in Brazilian farms, especially in dairy cattle. In many Brazilian states serological surveys showed high bovine leukosis virus (BLV) infection rates: 36% in Goiäs (Andrade and Almeida, 1991), 27% in Minas Gerais (Modena et al., 1984), 21% in Paranä (Kantec et al., 1983), 53% in Rio de Janeiro (Romero and Rowe, 1981), 21% in Rio Grande do Sul (Flores et al., 1990) and 45% in Sa¬ o Paulo (Birgel et al., 1988). Similar results were found in other Latin American countries: 50% in Argentina (Brunel et al., 1981), 14% in Colombia (Pena et al., 1985), 28% in Costa Rica (Ducreux et al., 1987), 36% in Mexico (Suzan et al., 1983) and 24% in Peru (Chung, 1983). The purpose of this work was to study some epidemiological aspects of BLV infection in dairy cattle raised in Sa¬ o Paulo state, Brazil. From 1980 to 1989, blood samples were collected from 978 Holstein cows kept on a dairy farm in Sa¬ o Paulo State. Animals were grouped according to their age and origin Tropical AnimalHealth and Production, 30 (1998) 13^15 # 1998 Kluwer Academic Publishers. Printed in the Netherlands

Fatores etários no leucograma de fêmeas zebuínas sadias da raça Nelore (Bos indicus)

In order to evaluate the influence of the age on the white blood cell counts of Nelore (Zebu) cattle, 158 blood samples from seven groups of different ages (group I-up to three months; group II-three to six months; group III-six to 12 months; group IV-12 to 24 months; group V-24 to 48 months; group VI-48 to 72 months and group VII-older than 72 months) were studied. The highest and lowest mean values observed were total white blood cell/mm3-16992±4104 (group III) and 10353±2397 (group VI); neutrophils/mm3-3931±1578 (group I) and 2416 ±1118 (group III); eosinophils/ mm3-999±499 (group V) and 265±276 (group II); basophils/mm3-67±88 (group VII) and 39±78 (group III); typical lymphocytes/ mm3-12758±3608 (group III) and 5906±1883 (group VI); atypical lymphocytes/ mm3-1310±603 (group II) and 760±419 (group VI) ; lymphocytes total/ mm3-14079±4027 (group III) and 6666±2059 (group VI); monocytes/mm3-27±62 (group I) and 0 (group III). The differences (p>0.05) observed among the groups in relation to total white blood cell, lymphocytes, neutrophils and eosinophils can be related to the influence of the age on leukogram of Nelore (Zebu) cattle raised in Sao Paulo- Brazil.Professores Assistentes da Escola de Medicina Veterinaria da Universidade Federal da Bahia. Professor Associado, Departamento de Clinica Medica da Faculdade de Medicina Veterinaria e Zootecnia da Universidade de Sao Paulo (USP), Av. Professor Doutor Orlando Marques de Paiva, 87, CUASO. Sao Paulo, SP, 05508-000. E-mail: borges@usp.br. Autor para correspondencia. Professor Titular, Departamento de Clinica Medica da Faculdade de Medicina Veterinaria e Zootecnia da USP. Professor Associado, Departamento de Clinica Medica da Faculdade de Medicina Veterinaria e Zootecnia da USP. Professor Assistente da Faculdade de Medicina Veterinaria da Universidade Federal do Parana. RESUMO

Influence of age on the leukogram values for healthy Nelore (Zebu) cattle

In order to evaluate the influence of the age on the white blood cell counts of Nelore (Zebu) cattle, 158 blood samples from seven groups of different ages (group I-up to three months; group II-three to six months; group III-six to 12 months; group IV-12 to 24 months; group V-24 to 48 months; group VI-48 to 72 months and group VII-older than 72 months) were studied. The highest and lowest mean values observed were total white blood cell/mm3-16992±4104 (group III) and 10353±2397 (group VI); neutrophils/mm3-3931±1578 (group I) and 2416 ±1118 (group III); eosinophils/ mm3-999±499 (group V) and 265±276 (group II); basophils/mm3-67±88 (group VII) and 39±78 (group III); typical lymphocytes/ mm3-12758±3608 (group III) and 5906±1883 (group VI); atypical lymphocytes/ mm3-1310±603 (group II) and 760±419 (group VI) ; lymphocytes total/ mm3-14079±4027 (group III) and 6666±2059 (group VI); monocytes/mm3-27±62 (group I) and 0 (group III). The differences (p>0.05) observed among the groups in relation to total white blood cell, lymphocytes, neutrophils and eosinophils can be related to the influence of the age on leukogram of Nelore (Zebu) cattle raised in Sao Paulo- Brazil.Professores Assistentes da Escola de Medicina Veterinaria da Universidade Federal da Bahia. Professor Associado, Departamento de Clinica Medica da Faculdade de Medicina Veterinaria e Zootecnia da Universidade de Sao Paulo (USP), Av. Professor Doutor Orlando Marques de Paiva, 87, CUASO. Sao Paulo, SP, 05508-000. E-mail: borges@usp.br. Autor para correspondencia. Professor Titular, Departamento de Clinica Medica da Faculdade de Medicina Veterinaria e Zootecnia da USP. Professor Associado, Departamento de Clinica Medica da Faculdade de Medicina Veterinaria e Zootecnia da USP. Professor Assistente da Faculdade de Medicina Veterinaria da Universidade Federal do Parana. RESUMO

Influence of age on leukogram values of healthy Nelore (Zebu) cattle.

In order to evaluate the influence of the age on the white blood cell counts of Nelore (Zebu) cattle, 158 blood samples from seven groups of different ages (group I-up to three months; group II-three to six months; group III-six to 12 months; group IV-12 to 24 months; group V-24 to 48 months; group VI-48 to 72 months and group VII-older than 72 months) were studied. The highest and lowest mean values observed were total white blood cell/mm3-16992±4104 (group III) and 10353±2397 (group VI); neutrophils/mm3-3931±1578 (group I) and 2416 ±1118 (group III); eosinophils/ mm3-999±499 (group V) and 265±276 (group II); basophils/mm3-67±88 (group VII) and 39±78 (group III); typical lymphocytes/ mm3-12758±3608 (group III) and 5906±1883 (group VI); atypical lymphocytes/ mm3-1310±603 (group II) and 760±419 (group VI) ; lymphocytes total/ mm3-14079±4027 (group III) and 6666±2059 (group VI); monocytes/mm3-27±62 (group I) and 0 (group III). The differences (p>0.05) observed among the groups in relation to total white blood cell, lymphocytes, neutrophils and eosinophils can be related to the influence of the age on leukogram of Nelore (Zebu) cattle raised in Sao Paulo- Brazil.Professores Assistentes da Escola de Medicina Veterinaria da Universidade Federal da Bahia. Professor Associado, Departamento de Clinica Medica da Faculdade de Medicina Veterinaria e Zootecnia da Universidade de Sao Paulo (USP), Av. Professor Doutor Orlando Marques de Paiva, 87, CUASO. Sao Paulo, SP, 05508-000. E-mail: borges@usp.br. Autor para correspondencia. Professor Titular, Departamento de Clinica Medica da Faculdade de Medicina Veterinaria e Zootecnia da USP. Professor Associado, Departamento de Clinica Medica da Faculdade de Medicina Veterinaria e Zootecnia da USP. Professor Assistente da Faculdade de Medicina Veterinaria da Universidade Federal do Parana. RESUMO

Avaliação cronológica da variação no volume globular sanguíneo de bovinos leiteiros

The packet cell volume was evaluated by the authors in 321 healthy female Holstein cattle raised at Campinas dairy region. Sao Paulo State. All the animais used in this assay were healthy and free of Leucosis, Tuberculosis, Brucellosis and blood parasites. The packed cell volume has been studied by method of hematocrit with capilary tubos. The results showed an influence of age on packed cell volume with average reference values of 30.12 ± 2.72%.