Efeito da Distância de Transporte e Condições Climáticas Sobre os Indicadores Fisiológicos de Bem-estar dos Bovinos.

Abstract

In the first chapter, the aim was to evaluate the effects of transport distance on the welfare of male and female cattle transported to the slaughterhouse during rainy and dry season, from the hematological parameters and physicochemical analysis of the carcass. A total of 297 bovines Nelore and crossbred, being 147 females and 150 non-castrated males. The animals were allocated in groups according to sex and distance traveled to the slaughterhouse: <50 km, 100-200 km, 201-300 km and> 300 km. Blood samples were collected during exsanguination for hemato-biochemical and the pH final (pHu) was measured in cold carcass after 24 hours of cooling. As results, transport over long distances cause increase in hematocrit, urea, creatinine, lactate and increase serum activity of creatine kinase (CK), aspartate aminotransferase (AST) and pHu of the carcass. Males had increased creatinine, CK and AST and higher pHu of the carcass. Females had increased in hematocrit, urea, glucose and lactate. The animals transported during dry season had increase in albumin, creatinine, glucose, CK and AST. The animals transported in the rainy season had increase in serum urea. The total proteins, hematocrit, lactate and pHu were affected both by dry and rainy season. We conclude that transport over long distances interferes with well-being, causing dehydration and physical stress, resulting in increased pHu of the carcass, contributing to form DFD meat. Males were more sensitive to physical stress and muscle injuries. Females showed greater reactivity to effects of stress and less capacity of adapt to stress. Animals transported during the dry season presented dehydration and increased emotional and physical stress. In the second chapter, the aim was to establish if there is a correlation between the colorimetric technique and the periodic-acid Schiff (PAS) staining method for quantification of glycogen, allowing the use of both techniques in the measurement of liver glycogen. Samples of 5 cm2 of liver were collected of 297 bovines after evisceration in slaughter line, packed in plastic bag, identified and refrigerated immediately after collection. Then, 1 cm2 samples of liver were fixed in 10% buffered formalin for histochemical analysis and the remainder frozen in a freezer at -20 °C for biochemical analysis of glycogen. For the histochemical analysis, the tissue was stained by periodic-acid Schiff (PAS) while to biochemical evaluation was used colorimetric method according to Dubois et al. (1956). A simple correlation analysis was performed to compare the glycogen content results obtained by the colorimetric and the PAS staining method. The significance level considered was 95%. The results show no significant correlation (R2 = 0.29) between the colorimetric method and the PAS staining for liver glycogen quantification. Thus, it can be concluded that the biochemical analysis by the colorimetric method, because it is a quantitative method, should be the methodology of choice to be applied for quantification of liver glycogen in the laboratory routine.