Variação de proteínas séricas em bezerros das raças nelore e holandesa do nascimento até os seis meses de vida

Abstract

Previous studies showed that Nelore calves’ active production of immunoglobulins is delayed compared to Canchim and Limousin calves, characterizing a possible physiologic difference between taurine and Zebu calves. In this study we compared serum proteins of Nelore and Holstein calves from birth to six months old. Blood samples were taken from 50 healthy calves (30 Nelore and 20 Holstein) in the following ages: 24 to 36 hours of life, and 15, 30, 60, 90, 120, 150 and 180 days. Serum total protein concentrations were measured by colorimetry; albumin, alfa, beta and gammaglobulin concentrations were measured by agarose gel electrophoresis; and IgG concentrations were estimated by the zinc sulphate turbidity test. A repeated measure ANOVA was used to test age effect. The passive transfer of immunity was successful in both breeds and the variation of serum proteins followed the normal pattern throughout the first six months of life. There were breed differences in serum gammaglobulin concentrations. The levels of gammaglobulin were higher at the end of the first day of life, and decreased to the lowest levels at 60 days in Nelore calves and 30 days in Holstein calves. The increase due to the active production of antibodies was precocious in Holstein calves (beginning at 60 days) and slower in Nelore calves (beginning at 90 days), demonstrating that Zebu calves can, in fact, develop active immunity capability later than taurine calves.