Carla Heloisa Avelino Cabral

Levels of supplementation for grazing beef heifers.

The objective of this experiment was to evaluate the effect of providing different levels of a supplement on the nutritional characteristics and productive performance of heifers on pasture during the rainy-dry transition and dry season in Brazil or tropical area. Thirty crossbred heifers with predominance of Zebu breed were used in a completely randomized experimental design. Treatments consisted of a mineral supplement and 0.5, 1.0, 1.5, or 2.0 kg/animal/d of a protein supplement containing 300 g crude protein (CP)/kg of dry matter (DM). In the rainy-dry transition season there was quadratic effect of the protein supplementation (p<0.10) on daily weight gain (DWG). A linear relationship (p<0.10) was found between increasing supplement intake and intakes of DM, organic matter (OM), crude protein (CP), ether extract (EE), non fibrous carbohydrates (NFC) and total digestible nutrients (TDN). Coefficients of apparent digestibility of CP, EE, and NFC increased linearly (p<0.10) with increasing supplement levels, but there was no effect on the DM apparent digestibility (p>0.10); the microbial efficiency (g CPmic/kg TDN) and the relationship of microbial nitrogen flow with nitrogen intake (g/g nitrogen intake) were negative linear profiles. In the dry season, the descriptive pattern least squares means showed a trend of stabilization of DWG from the supply of 0.98 kg of protein supplement; the intakes of DM, OM, CP, EE, NFC, and TDN showed increasing linear relationship (p<0.10) with protein supplement levels; the means of apparent digestibility coefficients of the different dietary fractions presented a linear-response-plateau (LRP); the microbial nitrogen flow (g/d) showed positive linear profile (p<0.10) for supplementation levels. It is concluded that supplementation improves the productive performance of grazing heifers and that 1.0 kg/d of supplement per animal gives the maximum increment of weight gain.

Compactação do solo e macronutrientes primários na Brachiaria brizantha cv. Piatã e Panicum maximum cv. Mombaça

The primary macronutrients have an important role in the forage fertilization, depending on their contribution to the production cost. This paper aimed to evaluate the effects of soil compaction on the concentration of primary macronutrients present in diagnostic leaves of Piata and Mombaca grasses. The experiment was conducted in a greenhouse with a randomized statistical design, consisting of eight treatments and three replications in 2 x 4, factorial scheme, with two grases (Piata grass and Mombaca) and four soil densities (1.0, 1.2 , 1.4 and 1.6 Mg m-3). Two harvest of shoots were made, the first 42 days after the plant thinning, and the second 46 days after the first cutting. In the first growing period, the soil compaction interfere with the absorption of nitrogen and phosphorus, while in the second growing period there is a limitation in the absorption of nitrogen and potassium. Nitrogen is the primary macronutrient most limited by soil compaction.

Levels of supplementation for grazing pregnant beef cows during the dry season

ABSTRACT - The objective of this study was to evaluate the effect of different levels of multiple supplement supply on the nutritional characteristics and productive performance of pregnant cows grazing on Brachiaria decumbens Stapf. during the dry season. The experimental area was composed of four 3.0 ha paddocks with availability of potentially digestible dry matter of 2,582 kg/ha. Twenty-eight crossbred pregnant cows with predominance of Zebu breed at body weight of 446±12 kg were utilized in a completely randomized experimental design. Treatments consisted of mineral supplement (control treatment) and supply of multiple supplement at 0.5, 1.0 and 1.5 kg/animal/day with 300 g crude protein (CP)/kg of dry matter (DM). There was quadratic effect of multiple supplementation levels on daily weight gain and a linear increase for finalbodyconditionscore.The intakes of DM, organic matter (OM) and total digestible nutrients presented no effect with levels of multiple supplement. The coefficientsofapparentdigestibilityofDMandOMhadcubiceffectwithmultiplesupplementationlevels.Therewasno effect of levels of multiple supplementation on the microbial nitrogen flowandefficiency,butthemicrobialnitrogenflowin relation to nitrogen intake showed decreasing linear profile.Thesupplyof1.0kgofmultiplesupplementoptimizestheperformance of grazing cows during the dry season.Key Words: multiple supplement, nutritional parameters, weight gain