Avaliou-se o desempenho de novilhos terminados em confinamento por 168 dias, alimentados com níveiscrescentes de concentrado na dieta (0,8; 1,1 e 1,4% do PV). Foram utilizados 18 animais meio sanguePurunã x Canchim, com média de idade inicial de 12 meses e média de peso inicial de 278 ± 18 kg. Foi feitaa avaliação do consumo de matéria seca total de silagem e concentrado, consumo de proteína, o ganho depeso médio diário e a conversão alimentar. O delineamento utilizado foi o inteiramente casualizado comas médias testadas pelo teste de Tukey a 5% de probabilidade. O consumo de matéria seca total aumentoulinearmente (P<0,01) com o aumento de concentrado na dieta, influenciados pelos níveis crescentes de concentrado.A conversão alimentar e o peso final não foram influenciados (P>0,05) pelo nível de concentradona dieta. Houve efeito dos tratamentos sobre o ganho de peso médio diário, ganho de peso total e consumode proteína (P<0,01). A suplementação com concentrado pode aumentar o desempenho em crescimento,porém, não melhora a eficiência alimentar.

The experiment was conducted at Estação Experimental Fazenda Modelo, Ponta Grossa, PR, with the objective of evaluate the effect of levels of concentrate in the diet on the performance of beef steers finished in confinament. Eighteen Canchim steers, with average age of 12 months and average weight of 309 Kg were fed with corn silage "äd libitum" plus a concetrate containing 25 % of soybean meal, 73 % of ground corn grain and 2 % mineral salt. The levels of concentrate in the diet were established on fases of live weight (PV), according to the following treatments: T1 (1% of PV), T2 (1,2% of PV) and T3 (1,4 of PV). There was no significant difference (P>0,05) with respect to the average daily gain, feed conversion and dry matter intake among treatments.

Improving the quality and energy content of rations increases performance in feedlot cattle, resulting in higher weight at slaughter, better carcass quality and a higher yield of non-carcass components. The purpose of this study was to evaluate the effect of increasing concentrate content in the ration on the carcass traits and weight of non-carcass components of young bulls finished in a feedlot. Eighteen young crossbred ½ Purunã x ½ Canchim bulls were used, with an average body weight (BW) of 278 kg and 12 months of age at the start of the experiment. The experimental design was completely randomized with three treatments and six replicates, where the treatments were the contents of 0.71, 0.97 and 1.24% BW day-1 of concentrate in the ration, on a dry matter (DM) basis. Corn silage was used as roughage and was provided ad libitum during the experiment. The young bulls were kept in the feedlot for 168 days and slaughtered at 17 months of age. There was a linear effect of concentrate content on the slaughter weight (SW) and hot carcass weight (HCW), which increased from 433 to 485 kg and from 248 to 280 kg between 0.71 and 1.24% BW in DM day-1 of concentrate. This represented an increase of 9.87 kg in SW and 6.16 kg in HCW for each 0.10% BW in DM day-1 of concentrate added to the ration. The hot carcass yield, rib eye area, subcutaneous fat thickness and the proportions of bone, muscle and fat in the carcass were not affected by the concentrate content and showed mean values of 57.3%, 79.6 cm2, 3.20 mm, 14.88%, 65.21% and 20.67%, respectively. There was a linear effect of concentrate content on the carcass temperature after cooling, which increased from 8.1 to 9.0 oC between 0.71 and 1.24% BW in DM day-1 of concentrate. An increase of 0.16 oC in the post-cooling carcass temperature for each 0.10% BW in DM day-1 of concentrate added to the ration was observed. The weight of internal organs and the perirenal and internal fat deposition were not affected by the concentrate content. The inclusion of 1.24% BW in DM day-1 of concentrate in the ration is recommended to obtain high SW and high HCW. Below this level, the carcass tissue composition and weight of non-carcass components are not modified.

This project has been carried out with the objective of evaluating the effect of protein supplementation on the performance of beef steers maintained in Hemarthia pastures during winter (May 5th through August 31st ,2000) at Estação Experimental Fazenda Modelo, IAPAR, Ponta Grossa-PR. Thirty six Canchim steers, with initial average age of 10 months and initial average weight of 190 kg were randomly alloted to the following treatments: Control-mineral salt only, commercial protein containing mineral salt, and on farm prepared protein containing mineral salt. The average intake (grams/animal/day) was 460, 250 and 70, respectively, for Commercial, on Farm and Control treatments. Animals were weighed at 28 day intervals after a period of 14 h without food. Average total gain (kg/animal) was superior (20,25 kg), (P<0,01) for animals that received the on farm made mineral salt-protein misture. Animals that received the Commercial mineral salt-protein mixture last 2,08 kg during the control mineral salt last 13,67kg (P<0,01).

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