Abstract We evaluated the influence of the substitution of soybean meal by detoxified castor cake on performance, digestibility of nutrients, nitrogen balance, hepatic and renal functions of pregnant goats fed with diets containing detoxified castor cake by alkaline solutions during the stages (first two-thirds and final third) of pregnancy. Three diets were provided: one based on soybean meal and the other two based on castor cake detoxified with whit calcium hydroxide or sodium hydroxide. Goats fed detoxified castor cake sodium hydroxide had lower consumption. Was no effect (P>0.05) of diets or stages on the digestibility of dry matter and nutrients. The goats that received the diets based on soybean meal and detoxified castor cake calcium hydroxide consumed larger amounts of nitrogen. The goats fed with diet the basis of SM had greater weight in the parturition day. The average levels of enzymes for hepatic and renal functions were within normal patterns. Of enzymes related to liver metabolism, only the gamma-glutamyl transferase increased in the final third of pregnancy. The present study demonstrated that detoxified castor by sodium hydroxide reduces the consumption of goats during gestation, but did not affect negatively the renal and hepatic parameters.

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.

ABSTRACT 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.