Anderson de Moura Zanine

Comportamento ingestivo de bezerros em pastos de Brachiaria brizantha e Brachiaria decumbens

An experiment was carried out to evaluate the ingestive behavior of calves on Brachiaria brizantha and Brachiaria decumbens pastures, under continuous stocking with variable stocking rate. The experimental design was entirely randomized, with two treatments (two pastures), and five replicates per treatment. The experimental period lasted 30 days, consisting of days 20 for adaptation of animals and 10 for behavioral evaluations that consisted of three periods of 24:00h each, in intervals of five days. The calves spent less time grazing Brachiaria brizantha pasture (9,8h) than they did on the Brachiaria decumbens (11,3h). Different rumination times had been observed, 6,8 and 6,4 h for the animals grazing Brachiaria brizantha and Brachiaria decumbens, respectively. We suggested that the selective behavior of the calves on the Brachiaria decumbens made them to eat good quality grass, thus they spent a similar rumination time to that observed for Brachiaria brizantha. The number of bites per minute was inferior for the Brachiaria decumbens, 31,2h, when compared with Brachiaria brizantha (the mean bite rate was 34,9 bites per minute). The calves had a larger daily gain to Brachiaria brizantha (390g day-1) than they had to Brachiaria decumbens (340g day-1).

Structural characteristics and herbage accumulation of Tanzania guineagrass subjected to rotational stocking

The aim of this study was to evaluate the structural characteristics and herbage accumulation of tanzania guineagrass (Panicum maximum cv. Tanzania) under rotational grazing and subjected to combinations of two grazing frequencies (time for the canopy to intercept 90 or 95% of the incident light) and two post-grazing heights (30 or 50 cm). Treatments were assigned to experimental units according to a 2 × 2 factorial arrangement in a completely randomized design, with three replications. Sward heights at pre-grazing were consistent during the experimental period and were of around 65 and 75 cm, for 90% and 95% of light interception (LI), respectively. Pastures managed with post-grazing height of 50 cm and 90% of LI had higher number of grazing cycles when compared with those submitted to post-grazing height of 30 cm and 95% of LI. Herbage mass production was higher in summer, intermediate in late spring and lowest in fall and winter and early spring. Herbage mass and lamina leaves production were higher in pastures managed with post-grazing height of 30 cm when compared with post-grazing height of 50 cm. Nevertheless, the effects of frequency on herbage mass production were associated with the post-grazing height used. The LI levels (90 or 95%) did not affect leaf lamina production. The combinations of frequency and severity of grazing resulted in little variation in the morphological composition of forage, except in the autumn, when there was a higher percentage of dead material in pastures managed with post-grazing height of 50 cm when compared with those with post-grazing height of 30 cm. The rotational grazing of tanzania guineagrass should be initiated when canopy intercepts 95% of incident light until a post-grazing height of 30 cm. When necessary and in order to generate flexibility in grazing management, the tanzania guineagrass can be grazed with 90% of light interception.

Características morfogênicas, estruturais e acúmulo de forragem do capim-tanzânia submetido a duas alturas e três intervalos de corte

The morphogenetic and structural characteristics and herbage accumulation were assessed of Panicum maximum cv. Tanzania subjected to two cutting heights (25 and 50 cm) and three cutting intervals (corresponding to the appearance of two, three and four leaf per tiller). A 2 × 3 factorial arrangement was used in a randomized complete block design with three replications. Leaf appearance rate decreased and phyllochron increased with low cutting frequency. In general, the final leaf length was shorter for the 25 cm compared to the 50 cm cutting height. Rates of leaf senescence and stem elongation tended to increase as cutting interval increased from two to three new leaves produced per tiller. Tiller mortality rate increased throughout the experimental period, and the high rates of tiller appearance and death indicated an intense turnover in tiller population. The pre-defoliation hight decreased with increase in cutting frequency, while the herbage mass tended to be greater in hte smaller cutting frequencies. Stem accumulation differed between cutting heights only at the second cut and was smaller for the two leaf than for the three and four leaf per tiller cutting intervals for the same second cut. The cutting interval of Tanzania grass should not exceed the time necessary to ensure the appearance of two to three leaves per tiller.

Comportamento ingestivo de eqüinos em pastagens de grama batatais (Paspalum notatum) e braquiarinha (Brachiaria decumbens) na região centro-oeste do Brasil

It was carried out an experiment to evaluate the ingestive behavior of horses grazing Paspalum notatum and Brachiaria decumbens pastures. It had been used a completely randomized experimental design, with two treatments (two pastures) and five replicates per treatment. The experiment lasted 40 days, consisting of 30 days for adaptation of animals on the pastures and 10 days to evaluate grazing behaviour, with three periods of 24 hours and intervals of five days. The horses spent more time grazing during the day on the Brachiaria decumbens pasture (10.58 hours) than did on the Paspalum notatum pasture (7.69 hours). At night, the situation was reversed, horses grazed less (2.91 hours) on the Brachiaria decumbens pasture. Overnight leisure time was larger on the Paspalum notatum pasture (4.15 hours) than Brachiaria decumbens pasture (1.42 hours). The higher total daily bites had been observed (22720) in the animals on Paspalum notatum when compared with Brachiaria decumbens where they decreased the quantity of bites (17166).