Efeito do desafio com lipopolissacarídeo sobre o comportamento e desempenho de bovinos

Abstract

The objective of the present study was to verify the effect of the challenge with LPS on the behavior and performance of beef cattle. The aim of the present study was to verify the effect of the challenge with LPS on the organism's homeostasis, behavior and performance of beef cattle. 16 beef heifers, around 14 months of age, weighing approximately 330 kg, were clinically healthy, managed in an intensive system with free access to water. The animals were divided into two groups: the LPS group (n = 8), which received two applications of 2 mL of saline solution containing 0.5 μg / kg body weight of LPS intravenously, with an interval of 24 hours; and the control group (n = 8) that received two applications of 2 mL of saline with the same time interval. All animals received an accelerometer collar for behavior assessment. During the challenge with LPS, the temperatures were verified, which increased to 39.9 ° C in the period from 2 to 6 hours, however it did not differ (P> 0.05) between the groups. In relation to the second challenge, a sharp rise in temperature was observed in 26 hours, reaching a temperature of 40.2 ° C. The concentration of calcium and phosphorus and the activity of paraoxanase-1 had no effect (P> 0.05) on serum activity. Regarding the animals' weight, average daily gain and carcass weight, the challenge with LPS did not change the parameters related to the final weight (P = 0.43) and the carcass weight (P = 0.94) of the animals respectively, however, there was a weight loss in the animals of the control group reaching a value of -24.5 ± 2.07 kg and a lower average daily gain, with a value of -6.12 ± 0.51 kg. In the behavior analysis there was no change in the rumination time, which was around 5.9 hours / d, the same occurred with the idle time which was around 15.4 h / d, however the activity was influenced by applying LPS, adding an estimated time of 2.65 h / d. Therefore, it is concluded that the challenge was able to produce an inflammatory response, but did not affect the concentrations of paraoxanase-1, calcium and phosphorus. Regarding performance and behavior, it was observed that there were no changes that could harm the animals' performance.