Average daily gain and reactivity in Caracu young bulls
Resumo

Ganho médio diário e reatividade em novilhos da raça Caracu
Abstract

Studies have shown associations between temperament traits and productivity on cattle industry, some results indicate that animals which adapt easily are less agitated, therefore there will be fewer losses in carcass due to the low incidence of hematomas and higher weight gain. The objective of this study was to associate the average daily gain in Caracu animals, subject to performance test (PT), with reactivity measured by flight speed test. The average daily gain was divided in three classes, considering 0.5 standard deviation below and above the average. The average gain classes 1, 2 and 3 was 1158.55 ± 89.48, 957.14 ± 54.77, 620.88 ± 127.41 g/day, respectively. The flight speed test (FS) measures how long the animal takes to cover a known distance after the release of the squeeze chute. Faster animals were considered more reactive. The study was performed at Centro APTA Bovinos de Corte from Instituto de Zootecnia-Sertãozinho, SP, in which were used 109 flight speed records, of 56 animals, obtained in the beginning and at the end of PT. Data were analyzed using the PROC MIXED (SAS 9.3). The model of analyses included the fixed effects of average daily gain classes (1, 2 and 3) and measures (1 and 2), besides the random-effects of animal and residue. The interaction classes measures, even as age as covariate, were excluded from the initial model, because they didn’t show significance at level of 5%. Significant differences weren’t observed (P>0.05) on reactivity of animals for the various average daily gain classes, evidencing that there was no relationship between performance and temperament in the animals evaluated. As in the present work, others studies performed in Centro APTA Bovinos de Corte, with Nelore animals also didn’t find correlations between average daily gain and the flight speed test. The reactivity in Caracu steers measured in the beginning and at the end of PT was significantly (P<0.01) different. Whereas at the second measurement, the animals were slower to cross the distance stipulated. This fact was expected, because at the end of the test animals were habituated to handling and so less reactive. The results of this study indicate that there is no relationship between temperament and weigh gain on the animals evaluated. Caracu animals adapt easily to weighing handling. 

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