The effects of differing post-weaning management systems applied during the wet season were evaluated on the performance of 108 young Nelore (Bos taurus indicus) bulls finished on grasslands or feedlot system during the dry season. In Exp. 1, three grazing heights (15 cm, 25 cm, and 35 cm) of Brachiaria brizantha (Hochst ex A. Rich) Stapf Marandu were evaluated during the wet season with bulls receiving 0.3% of body weight (BW) in supplementary feed. In Exp. 2, supplementation levels were decreased as grazing heights were increased such as: (1) low height (15 cm) and high supplementation (0.6% BW) (LH-HS); (2) moderate height (25 cm) and moderate supplementation (0.3% BW) (MH-MS); or (3) high height (35 cm) with no supplementation (HH-NS). In both experiments, at the end of the wet season, a half of the bulls were finished on grasslands and receiving 1.0 kg/100 kg BW of dietary supplementation while the remaining bulls were placed in a feedlot system. A non-linear regression test was applied (linear plateau) to estimate the point of stabilization of DMI on feedlot. The experimental design was completely randomized in a factorial arrangement 3 (post-weaning system) × 2 (finishing systems), consisting of three replicates (lots of three bulls) per treatment (n = 18, each Exp.). In the Exp. 1, the post-weaning system using 35 cm of grazing height had greater BW (P = 0.04) through the finishing phase in comparison with bulls grazing 15 cm of grazing height. However, the ADG during the initial 21 days of the finishing phase was changed by grazing height used during the post-weaning phase (P = 0.004), and by finishing system (P = 0.007). The post-weaning system did not alter the carcass weight (P = 0.63), but the bulls finished on grasslands exhibited greater carcass weight (P = 0.02) than bulls finished on feedlot. In the Exp. 2, non-supplemented bulls (HH-NS) took a longer time (±10%) to DMI stabilization on feedlot (P b 0.01). There were no changes in the carcass weight caused by post-weaning system (P = 0.84), or by finishing system (P = 0.14). The evaluated systems combining increasing grazing height and decreasing supplementation level during the post-weaning phase can be used during the wet season according to the economic background or production target, once these systems do not influence the finishing phase.

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A brucelose e a tuberculose são importantes zoonoses de distribuição mundial com grande relevância na bovinocultura (principalmente leiteira) que acarretam prejuízos econômicos vultosos e problemas sanitários na saúde pública. O objetivo deste trabalho foi analisar a prevalência da brucelose e da tuberculose em bovinos de duas propriedades leiteiras na região de São José do Rio Preto -SP. Os testes de diagnósticos utilizados foram os preconizados pelo Programa Nacional de Controle e Erradicação da Brucelose e Tuberculose (PNCEBT). Foram testados 141 animais para brucelose bovina, destes, 15 foram reagentes no teste de triagem com o AAT (antígeno acidificado tamponado) revelando uma prevalência de 10,64%. Destes 15 animais reagentes ao AAT, três foram confirmados pelo teste do 2ME (2-mercapto etanol), e dois foram reagentes também pela RFC (reação de fixação de complemento). Para tuberculose bovina foram avaliados 170 animais pelo teste cervical simples (tuberculinização) dos quais 42 animais foram positivos revelando uma prevalência de 24,7%. Estes animais foram testados novamente após o período de 60 dias com o TCC (teste cervical comparativo) e neste teste confirmatório quatro animais foram reagentes. Estes resultados demonstram que existem animais reagentes para as duas enfermidades estudadas mostrando a relevância do estudo da prevalência no estado de São Paulo. PALAVRAS-CHAVE:Bovinos. Brucella. Mycobacterium. Diagnóstico. SUMMARYBrucellosis and tuberculosis are important zoonosis of world distribution with great importance on bovine cultivation (mainly the milkmaid) that brings on huge economic damages and important sanitary problems on public health. The aim of this paper was to analyze the prevalence of these diseases in the bovine of two milk properties in the area of São José do Rio Preto city, São Paulo state, Brazil. The diagnosis tests used for these two diseases were the preconized by the National Program of Control and Eradication of Brucellosis and Tuberculosis ((NPCEBT). 141 animals were tested to bovine brucellosis. From these tested animals, 15 were reagent on the BAA (buffered acidified antigen) screening test, revealing a prevalence of 10.64%. From these 15 animals that were reagent to BAA, 3 of them were confirmed by 2-ME (2-mercaptoetahnol), and two of them were also reagent by the CFT (complement fixation test). 170 animals were tested for bovine tuberculosis with the simple cervical test (tuberculinization), where 42 animals were positive, revealing a prevalence of 24.71%. These animals were tested again after a period of 60 days with the CCT (comparative cervical test) and four animals were reagent in this confirmatory test. These results show that there are reagent animals to these two studied diseases, showing the relevancy of the prevalence study in São Paulo state.

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Our objective was to evaluate the effects of feeding 3-nitrooxypropanol (3NOP; Bovaer®, DSM Nutritional Products) at two doses on methane emissions and performance by feedlot cattle. The experiment was designed as a completely randomized block, in which 138 Nellore bulls (iBW, 360 ± 37.3 kg) were placed in collective pens (9 pens per treatment) and fed a high-concentrate diet (R:C, 11:89) according with the following three treatments: 1) 0ppm 3NOP /day; 2) 100ppm 3NOP/day, or 3) 150ppm 3NOP/day. For performance and DMI assessments the pen was the experimental unit. For methane emission evaluations, CH4 and DMI were assessed individually in 12 pens (2 bulls/pen, 8 bulls (experimental units)/treatment). Methane emission was measured for 6 consecutive days using the sulfur hexafluoride (SF6) tracer technique in two times over the experimental period (d15d -d21) and (105d to 111d), whereby the gross energy (GE) variables were calculated using equations. The individual DMI was measured using the two markers technique (Chromium oxide and indigestible NDF). The data were analyzed using the Mixed procedure of SAS and means comparison were carried out by Tukey’s test. Regardless of the level, dietary supplementation with 3NOP decreased (P < 0.001) methane emissions by 49.7% as expressed as g/d (146.0 vs. ~74 g/d−1); by 38.6% when expressed as g/kg ADG (91 vs ~56 g/kg ADG), and by 40.7% when expressed as g/kg DMI (13.5 vs. ~8 g/kg DMI). Likewise, dietary supplementation with 3NOP decreased (P < 0.001) the GE loss as a percentage of the GE intake by 42.4% (4.74 vs ~2.73%). However, feeding 3NOP had no effect on animalsˈ DM intake (~2.43 %BW; P = 0.23), ADG (~1.52 kg/d; P = 0.11) and HCW (~284 kg, P = 0.26). We conclude that Bovaer® can be used to effectively reduce methane emission by feedlot cattle without adverse effects on performance.