The lack of information on the growth of forage grasses in semi-arid environment, especially from the perspective of irrigation, is one of the obstacles to regular forage supply, as well as to the rational use of irrigation water. The objective with this study was to evaluate the leaf gas exchanges, biomass flow and structural characteristics of buffel grass cultivar Gayndah under different water supplies (30, 60, 90 and 120% of the reference evapotranspiration -ETo) during the dry season and dry-rainy season, in completely randomized design in a split-plot scheme with three repetitions. The experiment was conducted in Sobral, CE, Brazil (3° 45' 00.77" S and 40° 20' 38.55" W, altitude of 101 m) from September 2015 to January 2016. A higher photosynthetic rate was verified during the dry season, evidencing the adaptability of buffel grass to environments with water restriction. Overall, the best morphogenic and structural characteristics and the biomass production were observed in the dry season. The 90% ETo regime leads to maximum amount of forage accumulation, whereas the 30% ETo allows the maintenance of the cultivar Gayndah of buffel grass in a state of latency during the dry season.Morfofisiologia do capim-buffel cultivado sob diferentes suprimentos hídricos na estação seca e estação seca chuvosa RESUMO: A carência de informações sobre o crescimento de gramíneas forrageiras em ambiente semiárido, sobretudo sob a perspectiva de irrigação, é um dos entraves para a oferta regular de forragem, assim como para o uso racional da água de irrigação. Diante do exposto, objetivou-se avaliar as trocas gasosas foliares, o fluxo de biomassa e as características estruturais do capim-buffel cultivar Gayndah em diferentes suprimentos hídricos (30, 60, 90 e 120% da evapotranspiração de referência -ETo na estação seca e estação seca chuvosa, em delineamento inteiramente casualizado em esquema de parcelas subdivididas com três repetições. O experimento foi conduzido em Sobral, CE (3° 45' 0.77" S e 40° 20' 38.55" O, altitude de 101 m) no período de setembro de 2015 a janeiro de 2016. Foi verificada maior taxa fotossintética durante a estação seca, evidenciando adaptabilidade do capim-buffel a ambientes com restrição hídrica. De maneira geral, as melhores características morfogênicas e estruturais e a produção de biomassa foram observadas na estação seca. O regime de 90% da ETo proporciona o máximo de acúmulo de forragem, ao passo que o tratamento de 30% da ETo, possibilita a manutenção do capim-buffel, cultivar Gayndah em estado de latência durante o período de estiagem. Palavras-chave:Pennisetum ciliare, fluxo de biomassa, lâminas de irrigação, semiárido, trocas gasosas

The objective was to evaluate the intake, digestibility, nitrogen balance, and metabolic profile of lactating goats fed diets containing detoxified castor cake (DCC) by alkaline solutions during 150 days of lactation. Twenty-four Saanen and Anglo Nubian goats, approximately 17 months old (first lactation) and body weights of 43±2.97 kg, were distributed in a completely randomized block design with eight replicates. Treatments consisted of three diets, one containing soybean meal (SM) and two others containing DCC, with calcium hydroxide [Ca(OH) 2 ] and sodium hydroxide (NaOH). The diets significantly influenced the intake of dry matter (DM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), and total digestible nutrients (TDN). We observed a higher dry matter intake (DMI) in goats fed SM, similar to that of goats fed Ca(OH) 2 DCC. Intake of nutrients followed the same trend as DMI. There was no significant effect of diets on digestibility of DM, CP, EE, and NDF; however, we observed a significant effect of diets on the levels of nitrogen intake (NI) and urinary nitrogen (UN). The goats fed SM consumed a larger quantity of nitrogen, but all had the same nitrogen balance, indicating that goats fed DCC were more efficient. The diets did not influence renal and hepatic parameters. Inclusion of castor cake in the diet of goats in confinement is an attractive option, considering that goats fed DCC present lower feed conversion, and its use does not cause hepatic and renal alterations, suggesting that SM can be completely replaced.

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The objective of this study was to evaluate the influence of replacing soybean meal (SM) with castor bean cake (DCC), detoxified using two alkaline products, on the feeding behavior and physiological parameters of Saanen and Anglo-Nubian goat breeds with an initial body weight of 16.22 ± 0.67 kg. The treatments consisted of three diets that were isoproteic and isoenergetic: the first with a standard formulation based on corn and SM, the second with DCC detoxified using calcium hydroxide (Ca(OH)2 DCC), and the third with DCC detoxified using sodium hydroxide (NaOH DCC). A completely randomized design with a 3 × 2 (diets and breeds) factorial arrangement and four replicates per combination was used. A dietary effect on the intake of dry matter (DM) and NDFap (P = 0.02 and 0.01) was observed, with lower values for goats fed NaOH DCC than the other diets. The diets influenced feeding and rumination times (P = 0.04 and 0.03). An interaction (P = 0.04 and 0.01) between the breeds and the SM-based diet was found for time variables (other activity and idle time). Increased feeding and neutral detergent fiber (NDF) rumination efficiencies were observed for goats fed SM and Ca(OH)2 DCC (P = 0.03 and 0.01). Goats fed the NaOH DCC diet consumed large amounts of water, while Saanen goats urinated more times than did Anglo-Nubian goats. The diets had an effect on the heart rate and rectal temperature (P = 0.01 and 0.02), while the body surface temperature was influenced by the breed. Thus, Ca(OH)2 or NaOH DCC has a great potential to replace SM in the feeding of dairy goats. When used as diet for goats in the growth phase, NaOH DCC causes a reduction of DM and NDF intakes. Neither DCC negatively affected the physiological parameters of goats.

This study aimed to evaluate the physiological parameters and the biomass flow and structural characteristics of BRS Massai and BRS Tamani grasses under different irrigation conditions. The rating of gas exchange, biomass flow and structural characteristics were performed in dry periods and dry/rainy season, under the water supply of 30; 60; 90 and 120% of the reference evapotranspiration (ETo). The experimental design was completely randomized in a factorial arrangement 4x2 (water supply and grass). The experiment was conducted in pots with capacity for 7.5 dm³, using as substrate layer of 0-0.2 m soil. There was no effect (P < 0.05) between the gas exchange in the dry period, having the largest growing parameters of irrigation schemes. In the transition period of dry/rainy, we observed a reversal behavior in relation to the dry period, showing a rapid recovery of grasses under the minor water supply. It was observed quadratic behavior to concentrations of CO2 in the leaf mesophilic (Ci) with maximum point to the BRS Massai grass and minimum point to the BRS Tamani grass, where the major and minor Ci were 119 and 48 ppm in the water supply of 107 and 35% of ETo, respectively. In relation to the biomass flow, the BRS Tamani grass presented greater stem elongation rate and leaf senescence rate in relation to BRS Massai in both periods assessed. In the dry period, we observed a higher biomass production of green leaf blades in the BRS Tamani grass, while in the transition dry/rainy season, the results for this variable were similar, and at the same time that observed higher accumulation of green culm biomass to the BRS Tamani grass, which certainly affected its structure. It is concluded that the application of a minimum daily water supply of 30% of ETo allows the maintenance of BRS Massai and BRS Tamani grasses without incurring the death of tillers and reduction of regrowth vigor, whereas the water supply of 90% of ETo favors the morphophysiological characteristics, especially of BRS Tamani grass.