O objetivo deste trabalho foi avaliar o efeito de estratégias de pastejo rotativo sobre a composição morfológica da forragem consumida por bovinos de corte em pastos de Brachiaria brizantha cv. Marandu. Os pastejos foram realizados sempre que o dossel atingia 95 ou 100% de intercepção luminosa (IL) até as alturas pós-pastejo de 10 e 15 cm. Foi avaliada a composição morfológica das extrusas coletadas de animais fistulados no esôfago em três etapas ao longo do rebaixamento dos pastos. À medida que o rebaixamento progrediu, a proporção de lâminas foliares na extrusa diminuiu e a de colmos e de material morto aumentou. Pastejos iniciados com 100% de IL ou realizados até a altura pós-pastejo de 10 cm resultaram em menor proporção de lâminas foliares e maior de colmos e de material morto. O tratamento 95/15 foi consistente entre os tratamentos que apresentaram as maiores proporções de lâminas foliares e menores de colmos e de material e, mesmo no final do rebaixamento, apresentou, ainda, mais de 50% de proporção de lâminas foliares na extrusa. Os resultados obtidos indicam que, durante o rebaixamento do dossel, pastejos mais freqüentes e menos severos proporcionam aos animais a obtenção de dietas com elevada proporção de lâminas foliares, o que deve aumentar o valor nutritivo da forragem consumida.

Grazing strategies alter sward leaf area patterns of growth, affecting herbage accumulation and utilisation. The objective of this experiment was to evaluate the growth of marandu palisadegrass (Brachiaria brizantha cv. Marandu) swards subjected to strategies of intermittent stocking. The experiment was carried out in Piracicaba, São Paulo, Brazil, from October/2004 to September/2005. Swards were grazed at 95 and 100% canopy light interception (LI) to post-grazing heights of 10 and 15 cm, following a 2 × 2 factorial arrangement with four replications in a randomised complete block design. The response variables evaluated were: crop growth rate, relative growth rate, net assimilation rate, leaf area ratio and leaf weight ratio. In early and late spring, the highest crop growth rate was recorded for treatment 95/15 (11.2 and 10.1 g m -2 day -1 , respectively), along with high values of net assimilation rate (4.4 and 6.9 g m -2 day -1 , respectively), leaf area ratio (0.0095 and 0.0103 m 2 g -1 , respectively) and leaf weight ratio (0.56 and 0.56 g g -1 , respectively). To compensate reductions in net assimilation rate plants made some morphological and physiological adjustments increasing leaf area and leaf weight ratio. Relative growth rate and net assimilation rate were 26 and 50% higher, respectively, on swards grazed at 95% than at 100% LI. In early spring treatments 100/10 and 95/15 resulted in the highest relative growth rate (0.086 and 0.059 g m -2 day -1 , respectively repetições e um delineamento de blocos completos casualizados. Avaliaram-se a taxa de crescimento da cultura, a taxa de crescimento relativo, a taxa de assimilação líquida, a razão de área foliar e a razão de peso foliar. No início e final de primavera a maior taxa de crescimento da cultura foi registrada para o tratamento 95/15 (11.2 e 10.1 g m -2 dia -1 , respectivamente), associada a altos valores de taxa de assimilação líquida (4.4 e 6.9 g m -2 dia -1 , respectivamente), razão de área foliar (0.0095 e 0.0103 m 2 g -1 , respectivamente) e razão de peso foliar (0.56 e 0.56 g g -1 , respectivamente). Para compensar reduções em taxa de assimilação líquida a planta se ajustou morfológica e fisiologicamente aumentando a razão de área foliar e razão de peso foliar. A taxa de crescimento relativo e a taxa de assimilação líquida foram, respectivamente, 26% e 50% superiores nos pastos manejados com 95% relativamente àqueles com 100% de IL. No início de primavera os tratamentos 100/10 e 95/15 resultaram na maior taxa de crescimento relativo (0.086 e 0.059 g m -2 dia -1 , respectivamente). O tratamento 95/15 resultou no padrão mais favorável de crescimento (taxas de crescimento da cultura, crescimento relativo e assimilatória líquida), particularmente durante o período de transição entre inverno e primavera. Palavras-chave: Brachiaria brizantha, interceptação luminosa, manejo do pastejo, rebrotação Giacomini et al. 734

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Leaf area index is the main sward characteristic related to the processes of light interception and competition in plant communities. The objective of this experiment was to quantify and evaluate the composition of the leaf area on tillers of marandu palisadegrass (Brachiaria brizantha cv. Marandu) subjected to strategies of intermittent stocking. The experiment was carried out in Piracicaba, state of São Paulo, Brazil, from October/2004 to December/2005. Swards were grazed at 95 and 100% canopy light interception (LI) to post-grazing heights of 10 and 15 cm, following a 2 2 factorial arrangement with four replications in a randomised complete block design. Estimates were made of sward leaf area index, site filling, specific leaf area and the dimensionless ratio between tiller leaf area and volume (R), as well as the relative contribution of basal and aerial tillers to these variables. In early spring, values of leaf area index and specific leaf area were low when compared to the other seasons, and swards grazed at 95% LI presented higher site filling and specific leaf area than those grazed at 100% LI. This resulted in higher tillering activity and increase in leaf area index in late spring, indicating quick recovery and early return of swards grazed at 95% LI to growing conditions. Aerial tillers corresponded to an important morphological adaptation of marandu palisadegrass to increase its competitive ability. Treatment 100/10 resulted in the highest and 95/15 in the lowest R values throughout the experiment, suggesting an allometric pattern of growth of tillers during regrowth in order to compensate low tiller population and optimise the leaf area index. Grazing management practices can benefit from this knowledge by promoting ideal sward conditions to maximise and accelerate growth. (Trindade, 2007). The objective was to evaluate the effect of pre-grazing sward light interception (LI) and post-grazing height targets on leaf area formation (including the separate contribution of basal and aerial tillers) of intermittently stocked marandu palisadegrass swards.

RESUMO -Foram avaliadas características do sistema radicular (pré e pós-pastejo) dos capins aruana e tanzânia submetidos a doses de nitrogênio (150 e 300 kg ha -1 de N) e pastejados por ovinos em lotação rotacionada com três a sete dias de pastejo e período de descanso variável. O delineamento experimental foi o de blocos completos casualizados (dois) com duas repetições, em esquema de parcelas subdivididas (parcelas =capins e subparcelas=doses de N) e medidas repetidas no tempo. No pré-pastejo, o capim-tanzânia, na média entre doses de N e períodos de pastejo, apresentou maior quantidade de massa seca da matéria orgânica (MSMO) (1,7 mg cm -3 de solo) que o capim-aruana (1,2 mg cm -3 de solo), além de maior comprimento de raízes (119,1 cm cm -3 de solo e 68,7 cm cm -3 de solo, respectivamente). A dose de 300 kg ha -1 de N contribuiu para maior comprimento do sistema radicular (107,1 cm cm -3 de solo) que a dose de 150 kg ha -1 de N (80,7 cm cm -3 de solo). O crescimento radicular pós-pastejo demonstrou similaridade de comportamento entre as variáveis mensuradas, de modo que o crescimento de raízes se tornou mais evidente após a segunda semana de rebrotação. Na média de capins, doses de N e idades de crescimento, no período equivalente ao outono/inverno, o crescimento de raízes (em MSMO foi de 3,9 mg 100 cm -3 ) aumentou para 12,9 mg 100 cm -3 no inverno, caiu para 4,7 mg 100 cm -3 na primavera e elevou novamente para 17 mg 100 cm -3 no verão. Comportamento semelhante foi observado para comprimento e superfície de raízes, coincidindo os períodos de maior crescimento com os de maior pluviosidade. A dose de 150 kg ha -1 de N promoveu maior crescimento em comprimento e superfície de raízes que a dose de 300 kg ha -1 de N nos períodos de maior pluviosidade.Palavras-chave: fertilização nitrogenada, Panicum maximum, sistema radicular Root Mass and Growth from Aruanagrass and Tanzaniagrass under Nitrogen RatesABSTRACT -The root system (pre and post grazing) characteristics of aruanagrass and tanzaniagrass under two nitrogen rates (150 and 300 kg ha -1 N year) grazed by sheep in variable rotational stocking (three to seven grazing days) and variable rest period were evaluated in this study. The treatments were assigned to a complete randomized block (two) design with two replicates (plots = grasses and splitplots = nitrogen rates)within repeated measures. In the pre-grazing tanzaniagrass, averages within nitrogen rates and grazing period showed higher amount of dry matter of organic matter (DMOM) (1.7 mg cm -3 of soil) than aruanagrass (1.2 mg cm -3 of soil) and greater root length (119.1 cm cm -3 of soil x 68.7 cm cm -3 of soil). The 300 kg ha -1 N rate contributed to a higher root system length (107.1 cm cm -3 of soil) than the 150 kg ha -1 N rate (80.7 cm cm -3 of soil). Post-grazing root growth showed similar behavior among the variables measured and was more evident after the second regrowth week. Considering averages within grasses, nitrogen rates and growth age, in the period equivalent to Autumn/Winter, the DMOM ...

Feline oral squamous cell carcinoma (FOSCC) is characterized by high local invasiveness and early bone lysis. The late diagnosis largely limits the efficacy of therapy and increases treatment-related morbidity. The aim of this exploratory study was to assess the methylation pattern of 10 candidate genes and TP53 mutational status in histologic samples of FOSCC. Results were compared with normal oral mucosa and oral inflammatory lesions, in order to establish a gene panel for FOSCC detection. For 10 cats, the above analyses were also performed on oral brushing samples, in order to explore the utility of these methods for screening purposes. Thirty-one FOSCC, 25 chronic inflammatory lesions and 12 controls were included. TP53 mutations were significantly more frequent in the FOSCC (68%) than in the non-neoplastic oral mucosa (3%; P <.001). Based on lasso regression analysis, a step-wise algorithm including TP53, FLI1, MiR124-1, KIF1A and MAGEC2 was proposed. The algorithm allowed to differentiate FOSCC with 94% sensitivity and 100% specificity (accuracy, 97%). When applying the proposed algorithm on 10 brushing samples, accuracy decreased to 80%. These results indicate that the altered DNA methylation of specific genes is present in FOSCC, together with a significant proportion of TP53 mutations. Such alterations are infrequent in normal oral mucosa and chronic stomatitis in cats, suggesting their involvement in feline oral carcinogenesis and their utility as diagnostic biomarkers. Further studies on a high number of brushing samples will be needed to assess the utility of a screening test for the early detection of FOSCC.

Understanding the action of the nitrogen (N) in grasses can aid in pasture management and increase the efficiency of this nutrient. The objective of this study was to determine the influence of N rates and of the available N from the previous crop on Brachiaria ruziziensis cv. Comum. The experiment was conducted in a greenhouse. The treatments were arranged in a 2×4 factorial design and were distributed according to a fully randomized block design with four replications. Two N rates (0 and 15 mg dm-3) were applied at grass planting and four N rates were applied as topdressing after the first cutting (0, 15, 30 and 45 mg dm-3). The grass was cut twice above-ground. The comparison between N rates applied at planting was made using F test, and the degrees of freedom of the N rates applied as topdressing were broken down into orthogonal polynomials. The N rate of 15 mg dm-3 applied at planting the ruzi grass promoted increases in the numbers of leaves and shoot dry matter production. During the second growth, N rates (15, 30 and 45 mg dm-3) applied as topdressing increased the number of leaves and the shoot dry matter production. The available N from the previous crop (soybean) was sufficient for the initial tillering of the ruzi grass. This study showed that the correct management of N fertilization is necessary for ruzi grass when grown after a previous crop (soybean).

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