Desempenho de vacas de descarte em pastagem cultivada de inverno suplementadas com silagem de planta inteira e silagem de grão úmido

Abstract

The cool season pasture based in oat (Avena strigosa) + ryegrass (Lolium multiflorum) is one of the most widely used alternative of feeding in southern Brazil for finishing cattle in the off season. In addition to the pastures, is used as an alternative to energy supplementation to increase the stocking rate and weight gain. The aim of this study was to evaluate the effect of supplementation with wet grain silage and whole plant silage associated with silage moisture sorghum grain, through the performance of cull cows grazing on ryegrass + oats. The experiment was conducted in Dom Pedrito, from 06/08 to 19/09/2013. Was used 63 cull cows with weight frame and genetic pattern uniforms predominantly Angus and Hereford. The animals were divided into 3 groups of 21 animals each, in the following treatments: PASTmaintained exclusively grazing on ryegrass + oats; SGU-grazing oat and ryegrass + supplemented with wet grain sorghum, SPI-grazing ryegrass + oat and supplemented with sorghum whole plant silage + silage wet grain. The supplemented groups received the supplement, equivalent to 1% of body weight, fractionated twice daily, once in the morning and one in the evening. The animals were weighed at the beginning, after adaptation, in a middle weighing and at the end of the experiment. We assessed the average daily gain (ADG), stocking, gain by area and stocking for the three treatments. The ADG were subjected to analysis of variance and the means were compared by Tukey test at a 5% level of significance. The analyzes for the variables, gain by area, stocking and stocking were made by the Kruskal-Wallis test, considering a significance level of 5%. All analysis and graphs were made at ambient R. The ADG were 0.519, 0.987 and 0.922 kg, respectively for treatments PAST, SPI and SGU, did not differ between treatments and SPI SGU which were superior, treatment PAST differ among other showing the lowest gain. The other variables did not differ between treatments. Energy supplementation with either moisture sorghum grain or sorghum whole plant silage grain plus humid provide satisfactory weight gains for finishing cull cows grazing on winter. The values for the stocking did not differ significantly, even though numerically distinct, where these values are of great importance in a production system and may provide a higher gain per area. Energy supplementation in cultivated pastures winter causes substitution of consumption of forage by supplement, providing an increase in stocking rate supported for grazing and therefore a greater number of animals finished in the same area.