M. L. F. Nicodemo

Sobrevivência e crescimento inicial em campo de espécies florestais nativas do Brasil Central indicadas para sistemas silvipastoris

This work aimed to evaluate the rate of survival and the initial development of eleven native tree species established in existing pastures of Brachiaria brizantha at the Beef Cattle Center (Campo Grande, MS). The soil is a dystrophic clay Dark- Red Latosoil. The seedlings were planted in 16 rows, with 10 m between rows and 4 m between plants in a row. It was used a completely randomized design with four replicates. Each row contained at least one seedling of all the trees evaluated. A repeat was composed of four rows. The Tukey test (P=0,05) showed significant differences between the survival means, indicating that the seedling container and ecological succession groups (pioneer, early secondary, late secondary and climax) affected the results. The highest survival rates were found for the ipe (Tabebuia impetiginosa), caroba (Jacaranda cuspidifolia) and aroeira (Myracrodruon urundeuva). The highest rates of relative growth (P=0,05) in 12 months were observed for chico-magro (Guazuma ulmifolia), caroba (J. cuspidifolia) and canafistula (Peltophorum dubium). The growth rates of the pioneer species were higher (P=0,05) than the more advanced ecological groups in the successional scale (late secondary and climax). The differences increased over the time and during rainy season (P=0,05). The results indicated the use of three species to be established in the existing pasture of the Cerrado (savannahs), considering the increments in height, stem diameter and survival rate: chico-magro (G. ulmifolia), caroba (J. decurrens) and canafistula (Peltophorum dubium). The three species belong to the initial successional group.

Efeito do fósforo suplementar sobre o desempenho reprodutivo de vacas de corte em pastagem de Brachiaria humidicola

The objective of this experiment was to observe and quantify the effect of two mineral mixtures, as free-choice feeding, one without (M) and other with phosphorus supplement (MP), on the productive and reproductive performance of Nellore beef cows grazing Brachiaria humidicola. This work was conducted at the Fazenda Modelo (Embrapa-Centro Nacional de Pesquisa de Gado de Corte), located in Terenos, MS, Brazil, in two phases, 1st from 1988/92 and 2nd from 1992/94. During the 2nd phase, stocking rate, for the dry period, and suckling days were reduced (from 1.0 to 0.5 cows/ha and 210 to 90 days, respectively). Mineral intake (M = 76 and MP = 112 g/had/day), forage phosphorus level (wet season = 0.16%; dry season = 0.11%), liveweight (1st phase: M = 363± 3.3 and MP = 371± 3.8 kg; 2nd phase: M = 407± 5.7 and MP = 417± 6.5 kg), birth percentage (1st phase: M = 67± 3.3 and MP = 66± 3.5; 2nd phase: M = 75± 6.3 and MP = 80± 5.7) and weaning of calves (1st phase: M = 86± 5.0 and MP = 91± 5.3; 2nd phase: M = 55± 6.4 and MP = 67±5.7) were measured. Beef cattle is not responsive to P supplementation.

Use of bone, plasma and feces in the assessment of P status in cattle

Quinze novilhos Nelore foram distribuidos em tres tratamentos, consistindo de dieta basal capaz de proporcionar ganhos da ordem de 600 g/dia, suplementada (15 ou 11 g P/dia) ou nao (5 g P/dia) com fosfato monoamonico, para determinar as alteracoes provocadas por deficiencia de P em parâmetros osseos, sanguineos e fecais. Biopsias de costela foram obtidas aos 60 e 250 dias de experimentacao. Amostras de plasma foram coletadas quinzenalmente e amostras de fezes retais, analisadas em sete ocasioes, durante os 250 dias do experimento. Coleta total (diaria) de fezes foi feita em dois periodos, aos 60 e 243 dias, durante sete dias. Aos 60 dias, P expresso em relacao ao osso fresco, osso seco e desengordurado e ao volume de osso discriminaram entre os tratamentos. Aos 250 dias, a espessura da camada cortical e as concentracoes de cinzas e fosforo foram reduzidas na deficiencia de P. Observou-se queda na concentracao de fosforo inorgânico plasmatico (Pi), ja aos 12 dias de experimentacao, apresentando valores em torno de 3,0 mg % na epoca em que ganho de peso foi afetado (82 dias). Foi observada elevacao do Ca e da fosfatase alcalina na deficiencia de P, sem alteracoes na concentracao de hidroxiprolina do plasma. As concentracoes de P nas fezes aumentaram com a concentracao do elemento na dieta, mas a utilizacao de amostras coletadas do reto nao propiciou deteccao precoce de deficiencia de P. A definicao de niveis criticos para a determinacao de deficiencia apresentou problemas.

Produtividade e características biométricas do capim-braquiária em sistema silvipastoril

The objective of this work was to evaluate the productivity and biometric characteristics of signal grass (Urochloa decumbens) under grazing, in a silvopastural system. A system with native trees of commercial interest, planted in a set of rows with north-south orientation, with 17 m spacing was evaluated. A randomized complete block design with four replicates was carried out in a split-plot arrangement, with forage grass regrowth cycles evaluated in the plots and distances from trees in the subplots. Seven regrowth cycles were evaluated at four distances of the set of tree rows: at 2 and 6 m from trees at east, and at 2 and 6 m from trees at west. Dry matter productivity, leaf area index (LAI), specific leaf area (SLA), and plant height were measured. Forage productivity in the first two cycles and LAI in the second and third cycles reduced with shading levels higher than 39 and 40%, respectively. However, plant height increased with shadings greater than 53%, in the first four cycles, and SLA with shadings greater than 66%, in the first three cycles

REDUCING COMPETITION IN AGROFORESTRY BY PRUNING NATIVE TREES

The degree to which pruning helps reestablish balance in agroforestry was assessed in a system established in Sao Carlos, Sao Paulo, Brazil, in 2008. Seven native tree species were planted at a density of 600 trees/ha in five strips of three rows each, and annual crops were cultivated in the 17-m crop strips between the tree strips. Competition was established after 35 months, decreasing the aboveground biomass production of corn planted close to the trees. An assessment of black oats in the dry season following tree pruning showed that the proximity of trees caused reductions in plant and panicle density, aboveground biomass production, number of grains per panicle and grain weight. Because pruning was not sufficient to maintain crop yields, tree thinning is recommended in order to minimize competition and restore conditions for adequate crop production.

Metabolismo ósseo de vacas jovens Nelore em pastos de Brachiaria brizantha suplementadas ou não durante a seca com fósforo/cálcio e concentrado

Cows on diets deficient in P have not responded P supplementation during late pregnancy, although they may respond in early lactation. Bone metabolism of range cows has been monitored. All cows received complete mineral mixtures during wet season; during dry season, the imposed treatments were: complete mineral mixtures (MMC) or mineral mixtures lacking dicalcium phosphate, supplemented (MMR) or not (MM) with concentrate. Cows supplemented with the concentrate tended to show less variation on bone measurements. Calcium concentrations on bone ash were always below 34% without any symptom of Ca deficiency. Phosphorus concentrations on bone ash were also marginal, even in cows that received additional P all year round, while plasma P was always normal. Osteocalcin and bone alkaline phosphatase showed higher values (P<0.05) during late pregancy, when deoxypyridinoline concentrations were the lowest. Deoxypyridinoline increased at parturition and during early lactation. Cows that received concentrate also presented lower deoxypyridinoline mean values. After three years, beef cows did not show signs of bone loss in any of the treatments.

Vulnerability of ten eucalyptus varieties to predation by cattle in a silvopastoral system

AbstractSilvopastoral systems have been increasingly adopted in Brazil, often supported by public policies, such as the federal government’s “Low Carbon Agriculture” program. These systems integrate diversification, income generation and environmental protection. However, predation of mature trees by cattle can be a problem, causing large economic losses. As the causes of this predation are not precisely known, few alternatives are available to prevent or reduce damages. The present study aimed to evaluate the vulnerability of Eucalyptus grandis, E. saligna, E. pellita, E. dunni, E. urophylla, E. urograndis (clones I144, I224, C219 and H13) and the clone COP 1277, an E. grandis × E. camaldulensis hybrid, to predation by cattle. Damages caused by chewing leaves and bark and breaking branches and trunks were evaluated in a silvopastoral system comprised of Brachiaria decumbens, cattle and Eucalyptus spp. The cattle showed a marked selection of E. grandis and E. urograndis I144 clone. The eucalyptus types least prone to damage were E. pellita and E. urograndis H13 clone.

Desempenho de vacas jovens nelore em pastagens de Brachiaria brizantha suplementadas ou não com fósforo/cálcio e ração durante a seca

Many problems of the beef herd, including low pregnancy rates and low weaning weights, are related to inadequate intakes of energy and /or protein, as well as to minerals and vitamins deficiencies. The objective of the present study was to evaluate the performance of beef cows supplemented with phosphorus/calcium with or without energy/protein during the dry season. All cows received complete mineral mixtures during the wet season; during the dry season, the imposed treatments were: complete mineral mixtures or mineral mixtures lacking dicalcium phosphate, supplemented or not with concentrate. In the present conditions, protein/energy supplement showed no significant effects on weight gains and body condition of cows, as well as on calf weight at calving and at weaning. The calving interval did not differ between treatments, but primiparous heifers that received concentrate exhibited less open days. Phosphorus supplementation during the dry season did not affect negatively reproductive performance. The treatment effects were minimised by the good pasture condition.

Avaliação de níveis de fósforo na dieta de novilhos Nelore em crescimento: efeitos no desempenho

The adequacy of the recommendation of phosphorus for growing Nellore steers was evaluated by means of the weight gain, feed intake and feed:gain ratio during 250 days. Fifteen steers were fed a basal P-deficient but otherwise adequate in the other nutrients, enabling gains of 500 g/day. The diet was supplemented (treatment 1 = 15 g P/day, treatment 2 = 11 g P/day) or not (treatment 3 = 5 g P/day) with monoammonium phosphate. Phosphorus deficiency did not affect organic matter in vivo digestibilities determined at 60 days and at the end of the experiment, nor dry matter digestibility at the end of the experiment. Average dry matter intakes were 5.56, 5.28 and 3.69 kg/day, for treatments 1, 2 and 3, respectively. Feed intake, weight gain and feed:gain ratio were reduced by phosphorus deficiency. Steers fed 11 g of P/day gained 500-600 g/day without signs of deficiency.

Bark stripping by cattle in silvopastoral systems

Silvopastoral systems, consisting of the combined management of pastures, woody perennials and animals, are increasingly adopted throughout the world, especially in the tropics. However, reports of problems to the trees caused by the animals grazing these areas are also increasing. Damages inflicted by cattle to adult trees may include branch breakage, trunk breakage, leaves browsing and bark stripping. Bark stripping may cause severe damage to the trees: it can decrease the value of the timber, and the injuries may lead to diseases or even death of the tree. Bark stripping is caused by multiple factors. It can be related to (i) dietary deficiency (food quantity or quality; fiber, protein, energy, mineral deficiencies); (ii) social learning—from dam or herdmates; (iii) learning and post-ingestive feedback; (iv) stress and boredom, although the presence of trees gives cattle the opportunity to broaden the repertoire of natural behaviors; (v) pharmaceutical compounds used to control/treat diseases. In this article we review reports of bark stripping caused by livestock, specially cattle and sheep, characterizing the conditions for the occurrence of damage. We suggest planning and management strategies that could decrease the risk of bark stripping to trees in silvopastoral systems.