Total Digestible Nutrient Content Research Articles

Responses to administration of growth hormone releasing hormone and glucose in steers receiving stair-step and extended restriction on feeding

In this study, we assessed the temporal response of growth hormone (GH)/ghrelin to the intravenous administration of GH releasing hormone (GHRH) in 11- (period 1) and 15-month-old (period 2) Korean native steers, as well as the insulin induction response to glucose administration after completion of the feeding scheme in 11-month-old Korean native steers experiencing stair-step and extended restriction feeding schemes. The experiment was divided into periods 1, 2, 3, and 4 with durations of 3, 2, 4, and 2 months, respectively. The control group (n=9) was fed according to a standard feeding program during all 4 periods. The T1 (n=9; stair-step fed group) was fed a diet with total digestible nutrients (TDN) at concentrations 20% less and more than the TDN concentration fed to the control group in periods 1 and 3 and periods 2 and 4, respectively, whereas the T2 (n=9; extended restricted group) was fed increasing levels of TDN, having concentrations of 30%, 20%, 10% less than and 20% more than the TDN concentration of control group, during periods 1, 2, 3, and 4, respectively. Randomly chosen steers (n=4, total 12 heads) from the C, T1, and T2 groups were used for the experiment of GHRH and glucose administration. Compared to the control group, the T1 showed elevated levels of plasma GH and insulin after GHRH and glucose administration (p<0.05) and significantly greater body weight gain and feed efficiency. Although the total amounts of ghrelin in plasma were significantly decreased in the T1 group after GHRH administration (p<0.05), GHRH treatment did not affect the acyl ghrelin concentration in the plasma during compensatory growth. The results illustrate that stair-step feeding can promote growth performance by altering the endocrine responses associated with energy utilization, such as the production of GH, ghrelin, and insulin, in steers.

Evaluation of models for prediction of the energy value of diets for growing cattle from the chemical composition of feeds

The objective of this study was to estimate and evaluate the contents of apparently digestible fractions of crude protein, ether extract and non-fibrous carbohydrates, the digestible fraction of the neutral detergent fiber and the content of total digestible nutrients (TDN) from the chemical composition of feeds in growing cattle fed different diets. Fourteen F1 Red Angus × Nellore young bulls with average age and weight of 12 months and 287±36 kg were used. Animals were fed elephant grass silage, corn silage or signal grass hay, with or without supplementation of 200 g concentrate per kg of the total diet. The experiment consisted of two 13-days periods, in which the concentrate supplementation was crossed over animals. The values of digestible fractions and the TDN content observed were obtained based on total collection of feces. Several sub-models applied to the different digestible fractions were assessed and discussed. Estimates of the TDN content in the diet were produced from the combination of sub-models applied to the individual digestible fractions. The TDN content was more efficiently predicted from the sub-models proposed by Detmann et al. (2010) when biological procedures for the estimation of the undegradable fraction of the protein and the potentially degradable fraction of the neutral detergent fiber were considered.

Effect of feeding different proportions of groundnut haulms (Arachis hypogaea) and cluster bean straw (Cyamopsis tetragonoloba) on nutrient utilisation and serum biochemical parameters in dromedary camels

The effect of feeding different proportions of groundnut haulms (Arachis hypogaea) and cluster bean straw (Cyamopsis tetragonoloba) on nutrient digestibility, nutritive value, nutrient intake and serum biochemical parameters was studied using nine male dromedary camels of Bikaneri breeds (637.5 kg average body weight; 8-9 years of age). Groundnut haulms (GNH) and cluster bean straw (CBS) were fed in one of three ratios, 75:25, 50:50 and 25:75 in treatments T(1), T(2) and T(3), respectively. In all treatments, concentrate mixture was fed as per requirement of the camels. The groundnut haulms were more nutritive as compared to the cluster bean straw. The nutrient digestibility of dry matter, organic matter, crude protein (CP), crude fibre and acid detergent fibre was better in T(1) than T(2) and T(3). Likewise, the CP, digestible crude protein and total digestible nutrient contents were significantly higher in T(1) followed by T(2) and T(3). There was non-significant affect on average daily gain of camels. However, dry matter intake, digestible crude protein intake and total digestible nutrients were better in T(1) as compared to T(2) and T(3). The total water intake per kilogram of dry matter intake (litres) was 2.98, 2.89 and 2.68, respectively, in T(1), T(2) and T(3). The camels in all the treatments were in positive nitrogen, calcium and phosphorus balance. The treatments had a significant effect on serum biochemical parameters like glucose, cholesterol, aspartate transaminase and creatinine. The results may conclude that feeding of higher proportion of groundnut haulms as compared to cluster bean straw has pronounced improvement in nutritional utilisation by the camels.

Intake, digestibility and nitrogen use efficiency in crossbred F1 Holstein × Zebu grazing cows

The objective of this study was to evaluate intake, digestibility and nitrogen (N) compounds use efficiency in F1 Holstein × Zebu grazing cows. Eighteen crossbred cows (six Holstein × Gir, six Holstein × Guzerat, and six Holstein × Nellore) were used in the experiment, constituting three experimental treatments in simple random samples, under the same feeding conditions. At the estimation of individual intake at grazing, titanium dioxide was used for estimating fecal excretion and indigestible neutral detergent fiber, in order to determine pasture intake. There was effect of the lactation period on nutrient intake, except for the intakes of dry matter (DM), organic matter (OM) and total digestible nutrients (TDN) in % of body weight (BW), as well as those of non-fibrous carbohydrates (NFC), in kg. The digestibility coefficients of crude protein (CP), neutral detergent fiber corrected for ash and protein (NDFap) and the contents of TDN varied in function of the lactation period, whereas the coefficients of digestibility of DM, ether extract (EE) and OM did not present such effect. The total milk production projected at 305 days of lactation for Holstein × Gir cows was superior in relation to Holstein × Guzerat and Holstein × Nellore cows. The excretion of urea into urine and of urea N into the milk and the plasma presented quadratic behavior in function of the lactation period. The utilization of the genetic group from Holstein × Zebu grazing cows does not cause alterations in intake, nutrient digestibility or nitrogen use efficiency; however, there is variation in function of the lactation period. Holstein × Gir cows presented greater accumulated production during lactation and persistence, followed by Holstein × Guzerat and Holstein × Nellore cows.

Avaliação nutricional, durante a amamentação, de tourinhos em pastejo recebendo suplementação proteica da amamentação à terminação

O objetivo neste estudo foi avaliar as condições nutricionais de tourinhos em aleitamento, a pasto, recebendo suplementação com concentrados proteicos durante a época de transição águas-seca. Foram utilizados 52 bezerros mestiços com idade média inicial de 130 dias. Os animais foram distribuídos em quatro lotes, alojados em piquetes de Brachiaria decumbens Stapf junto com suas mães, onde receberam uma das quatro estratégias de suplementação: três suplementos concentrados, ou sal mineral (controle). Os suplementos concentrados diferiram quanto ao nível de proteína. Após 45 dias, realizou-se a avaliação nutricional dos animais, que incluiu a estimação do consumo e da digestão de nutrientes e das características do metabolismo proteico. A estimação do consumo e da digestibilidade foi feita utilizando-se os indicadores: LIPE®, dióxido de titânio e fibra em detergente neutro indigestível. Realizou-se ainda coleta de amostras de urina e de sangue. O efeito de suplementação e os efeitos linear e quadrático do nível de proteína no concentrado foram avaliados pela decomposição da soma de quadrados em contrastes ortogonais, adotando-se α = 0,10. O consumo de concentrado substituiu parte do pasto ingerido pelos bezerros e aumentou a ingestão de proteína, a digestibilidade da matéria seca e matéria orgânica, o teor de nutrientes digestíveis totais e a excreção de nitrogênio na urina. O nível de proteína no suplemento tem efeito linear positivo sobre a ingestão diária de proteína, a digestibilidade de todos os nutrientes e o teor de nutrientes digestíveis totais e efeito quadrático sobre a excreção de nitrogênio na forma de ureia na urina.

Effect of harvesting stages on forage yield and quality of different leaf types pea cultivar.

This study is aimed to determine the effects of three different harvesting stages (beginning of flowering, full flowering and seed filling) on forage yield and quality of different leaf type pea (Pisum sativum L.) cultivars. Two semi-leafless cultivars (Ulubatli and Kirazli), two leafed cultivars (Golyazi and Urunlu) were used in this research. Dry matter (DM) yield, crude protein (CP) ratio, CP yield, acid detergent fibre (ADF), neutral detergent fibre (NDF), total digestible nutrients (TDN) and relative feed value (RFV) were determined. According to two years averages, Golyazi had the highest DM (2415 kg ha -1 ) and CP yield (442 kg ha -1 ). Harvesting at the late stages caused a reduction in forage quality. Contents of CP, TDN and RFV decreased with advancing growth while DM yield, CP yield, ADF and NDF contents increased.

Effect of Harvest Date on Yield, Composition, and Nutritive Value of Corn Stover and DDGS

Efficient utilization of the non-grain portion of corn plant and distiller's grains for ruminants and the grain for ethanol will allow optimization of both food and fuel production. Corn stover can be effectively used as animal feed if it is collected before in-field dry-down. This study determined the yield and nutritive value of corn stover, distiller's dried grains with solubles (DDGS), and feed value enhanced stover (FVES) (a mixture of corn stover and DDGS) on different corn harvest dates, and determined the harvest time that maximizes whole-plant utilization. Corn and corn stover were harvested at different dates from 21 August to 23 November in 2009, and DDGS samples were produced from the corn samples collected at different harvest dates by dry grind fermentation. From 21 August to 23 November, dry matter yield of the stalk and leaf fraction and the cob decreased by 37.4% and 9.8%, respectively. During the same time period, neutral detergent fiber, acid detergent fiber, and lignin concentrations in the stalk and leaf fraction increased by 16.8, 12.7, and 1.0 percentage points, respectively, while crude protein concentrations decreased by 4.1 percentage points. For FVES, both the highest dry matter yield and the highest total digestible nutrient concentration were reached when corn just reached physiological maturity. Corn and corn stover can be harvested at the corn physiological maturity stage for maximum dry matter yield and optimum nutrient quality of FVES for ruminants, leaving more corn for ethanol production.

Digestibilidade total e parcial e balanço nitrogenado em bovinos em pastejo no período das águas recebendo suplementos com nitrogênio não-proteico e/ou proteína verdadeira

Objetivou-se avaliar o efeito de diferentes relações entre proteína verdadeira e nitrogênio não-proteico sobre a digestibilidade, a síntese de proteína microbiana e o balanço de compostos nitrogenados em bovinos em pastejo durante o período das águas. Foram utilizados cinco novilhos mestiços Holandês × Zebu, castrados, com peso vivo inicial de 335±35 kg fistulados no rúmen e no abomaso. Os tratamentos foram: controle (somente pasto); e suplementos com ureia; com 2/3 de compostos nitrogenados oriundos da ureia e 1/3 de compostos nitrogenados oriundos da albumina; com 1/3 de compostos nitrogenados oriundos da ureia e 2/3 de compostos nitrogenados oriundos da albumina; e com albumina. Foram fornecidos 200 g/dia de proteína bruta (PB) a partir dos suplementos. O experimento foi conduzido segundo delineamento em quadrado latino 5 × 5, com cinco períodos experimentais, cada um de 15 dias. A suplementação não afetou os coeficientes de digestibilidade total nem o teor de nutrientes digestíveis totais da dieta; elevou as estimativas do coeficiente de digestibilidade aparente ruminal da PB, que migraram de negativa, no tratamento controle, para positivas, porém não diferentes de zero, nos tratamentos envolvendo suplementação. O fornecimento de suplementos elevou a concentração de nitrogênio amoniacal ruminal. O balanço de compostos nitrogenados aumentou com a suplementação. A substituição de ureia por albumina influenciou de forma cúbica o balanço de compostos nitrogenados, cuja estimativa foi maior para o suplemento com 1/3 de PB oriunda da ureia. A eficiência de síntese microbiana no rúmen não foi influenciada pelo fornecimento ou pela composição dos suplementos. A suplementação de bovinos em pastejo com fontes de compostos nitrogenados degradáveis durante o período das águas amplia a eficiência de uso do pasto, principalmente por ampliar a retenção de compostos nitrogenados no organismo.

Produção, composição bromatológica e índice de clorofila de braquiárias após o consórcio com milho

We evaluated the effect of fertilization with 0, 50, 100 and 200 kg/ha of N, applied in each four growth intervals in the winter/spring season on dry matter yield in 30 days (DMY), leaf chlorophyll index (LCI) and total digestible nutrients (TDN), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin contents, and correlation equations of LCI with DMY and CP content in the marandu and ruziziensis grasses after intercrop arrangements with corn in Red Latosol (Oxisol) under irrigation. The major DMY occurred with photoperiod increasing, however, there were different responses to this attribute over of growth intervals, between and among the grasses with the N fertilization. In irrigated crop- livestock integration under savannah soil is technicality viable the cultivation of marandu and ruziziensis grasses, established by intercrop with corn at sowing or at the N fertilization. As even, in the N fertilization absence, produced satisfactory amounts of forage, with 1733 kg/ha (DMY), at the time of greatest scarcity of roughage to animals (winter/spring season). However, after the corn harvest, the N fertilization increase the DMY and improves the chemical composition, increasing the LCI, and CP and TDN contents, and decreasing NDF and ADF contents in the winter/spring season.The best correlation equations in function of LCI were logatithmica for DMY and potential for CP of the marandu grass and potential for both attributes of the ruziziensis grass.

Effect of anthocyanin‐rich corn silage on digestibility, milk production and plasma enzyme activities in lactating dairy cows

Anthocyanin in purple corn (Zea mays L.) has been reported to show several functional and biological attributes, displaying antioxidant, antiobesity and antidiabetic effects in monogastric animals. The objective of this study was to investigate the effect of feeding anthocyanin-rich corn (Zea mays L., Choko C922) silage on digestibility, milk production and plasma enzyme activities in lactating dairy cows. The cows were fed diets based on the control corn or the anthocyanin-rich corn silage (AR treatment) in a crossover design. The anthocyanin-rich corn silage-based diet had a lower starch content, nutrient digestibility and total digestible nutrients content when compared to the control diet. The milk yield, lactose and solids-not-fat contents in the AR-treatment cows were lower than in the control cows. The feeding of the anthocyanin-rich corn silage led to a reduction in aspartate aminotransferase (AST) activity and an increase in superoxide dismutase (SOD) activity in the plasma. These data suggest that the anthocyanin-rich corn has a lowering effect on AST activity with concomitant enhancement of SOD activity in lactating dairy cows. However, a new variety of anthocyanin-rich corn with good nutritional value is needed for practical use as a ruminant feed.

Fermentation parameters, quality and losses in sugarcane silages treated with chemical additives and a bacterial inoculant

The objective of this trial was to evaluate chemical additives and a bacterial inoculant on the inhibition of alcoholic fermentation and reduction of losses in sugarcane silages. Treatments were (doses on a fresh forage basis): without additive (control); urea (10 g/kg); urea (5 g/kg) + sodium benzoate (0.5 g/kg); sodium benzoate (1 g/kg); urea + ammonium sulfate in a 9:1 relation (10 g/kg); Lactobacillus buchneri (5 × 104 cfu/g). Silages were produced in 10.16- × 30-cm PVC tubes, provided with tight lids adapted with Bunsen valves for gas losses quantification. Minisilos were opened 139 days after ensiling. Ethanol content (227 g/kg dry matter - DM) and total DM loss (30%) were high in the control silage. All additives, except benzoate, decreased ethanol concentration in silages. Inoculation with L. buchneri increased acetic acid content in the silage, resulting in a 41% reduction in ethanol content and the lowest gas loss among treatments (15.2%). There was synergistic effect between additives for the combined use of urea and benzoate. Silage treated with urea + ammonium sulfate has higher content of total digestible nutrients than the silage treated with urea exclusively.

Silagem de capim-elefante aditivada com produtos alternativos

The objective was to evaluate the fermentation pattern and chemical composition of elephant grass silage using different additives. The experimental design was completely randomized with six treatments (elephant grass no additive; with 100 kg of rice bran ton-1 of green mass (GM); with 100 kg of soybean hulls ton-1 GM; with 100 kg of corn meal ton-1 GM; with 200 kg of sugar cane ton-1 GM; with inoculants) and four replications. PVC silos were used, adopting a density of 600 kg of green mass m-3. With the exception of inoculant, all additives used resulted in increased dry matter content (27.95 to 31.65%) and soluble carbohydrate contents (15.20 to 17.14%) in the forage being ensiled. The additives promoted an adequate fermentation pattern for pH values (3.70 to 3.96) and ammonia nitrogen (3.67 to 4.44% of total N) observed in the silage. The rice bran additive yielded silage with higher contents of crude protein (6.41%) and total digestible nutrients (61.91%) compared to the treatment without any additive.

Green propolis extract as additive in the diet for lambs in feedlot

The objective of this paper is to assess the effects of the inclusion of different levels of green propolis extract in the diet of lambs in feedlot on ingestive behavior, nutrients digestibility, physiological parameters and performance. Eight lambs were distributed in double Latin Square with four treatments, corresponding to the inclusion levels (4, 8, 12, 16 mL) of green propolis ethanolic extract (30 g of ground crude propolis was infused in a 100-mL hydroalcoholic solution, 700 mL/L). The diets were composed of Brachiaria brizantha cv. MG5 hay and a commercial concentrate (roughage:concentrate ratio was 50:50) in a dry matter basis. No effect was observed on dry matter (31.2 g/kg of BW), crude protein, ether extract, neutral detergent fiber, non-fibrous carbohydrates and total digestible nutrients content (TDN) intakes. No significant effect was seen on the digestibility coefficients, presenting an average of 65.94% of TDN. The green propolis extract levels do not have a significant effect on behavior or physiologic parameters. Seeking to maximize feeding efficiency, the inclusion of 7.60 mL/day (2.1189 mg of dry matter and 0.1123 mg of flavonoids) of green propolis extract in the diet of lambs in feedlot is recommended.

Sugar cane treated with calcium hydroxide in diet for cattle: intake, digestibility of nutrients and ingestive behaviour

The objective of this work was to evaluate, in bovines, the intake and apparent digestibility of nutrients, ingestive behaviour and content of total digestible nutrients (TDN) of diets based on sugar cane treated with calcium hydroxide. It was used four cows with average body weight of 412.06 kg ± 37.3 kg. The study included inclusion of calcium hydroxide at the doses 0, 8, 16 and 24 g/kg of sugar cane in natural matter basis fed in diets with 65% of roughage and 35% on concentrate, based on dry matter (DM). It was used a 4 × 4 Latin square experimental design with four treatments and four periods. Calcium hydroxide doses affected nutrient intake: DM intake was 7.88 kg/day at the dose of 14.99 g of calcium hydroxide, organic matter (OM) intake was 6.75 kg/day at 10.94 g; intake of neutral detergent fiber (NDF) of 3.33 kg/day with a dose of 13.93 g; and intake of acid detergent fiber (ADF) of 2.12 kg/day with a dose of 10.51 g. Digestibility coefficients showed a quadratic effect for doses of inclusion of calcium hydroxide. Dry matter digestibility was 72.88% with a dose of 11.65 g of calcium hydroxide, OM digestibility was 75.12% with 12.09 g; NDF digestibility was 58.67% with 12.11 g; ADF digestibility was 52.97% with 9.36 g and TDN digestibility was 71.42% with 10.92 g. There was no effect of the treatment for activities of rumination and total idle. Chewing time, number of bolus chewed and time for rumination of each bolli presented effect. Calcium hydroxide enabled greater intakes and digestibility of nutrients, especially from the cell wall, favoring the use of nutrients from the diet containing sugar cane, recommending a dose of 8-12 g.

THE PERFORMANCE OF JAVA AND ONGOLE CROSSBRED BULL UNDER INTENSIVE FEEDING MANAGEMENT

This study was set up to evaluate the performance of Java and Ongole Crossbred (OC) bulls fedconcentrate and rice straw. A total of four Java bulls and four OC bulls were used in this experiment. Thebulls were fed concentrates (50% of the total dry matter feed requirement) and rice straw (ad libitum).The concentrates were consisted of rice bran, beer waste product, copra meal, minerals, with crudeprotein (CP) and total digestible nutrients (TDN) contents of 15.32% and 73.09%, respectively. Theaverage daily gain (ADG), dry matter intake (DMI), protein and energy intake, and feed conversion ratio(FCR) were observed. The results of this study showed that the ADG, DMI, CP and TDN intake, andFCR were not significantly different (p&gt; 0.05). The ADG of Java and OC bulls were 0.58 kg and 0.78kg, respectively. The averages of DMI, CP and TDN intake were 6.59 kg (2.09% of BW), 0.81 kg and4.34 kg for Java bulls whereas for OC bulls were 6.42 kg (2.11% of BW), 0.78 kg, and 4.20 kg,respectively. The FCR of Java bulls was 11.49 and those of OC bulls was 9.21. It can be concluded thatJava and OC bulls raised intensively and fed concentrate and rice straw had the similar performance.

Parâmetros nutricionais e produtivos em bovinos de corte a pasto alimentados com diferentes quantidades de suplemento

Foram conduzidos dois experimentos com o objetivo de avaliar o efeito da quantidade de suplemento sobre o consumo, a digestibilidade, o ganho de peso e a eficiência de síntese microbiana em bovinos de corte. No experimento 1 foram utilizados quatro novilhos Holandês-Zebu, não-castrados, com peso médio de 250 kg, fistulados no esôfago, rúmen e abomaso. O suplemento foi composto por farelo de algodão, grão de milho triturado, mistura mineral e ureia/sulfato de amônio. As dietas foram: controle (sal) e suplementos oferecidos nos níveis de 0,33; 0,66 e 1% do peso corporal (%PC). Os consumos máximos de matéria seca (MS), fibra em detergente neutro (FDN) e nutrientes digestíveis totais (NDT) foram estimados em 1,09; 0,73 e 1,20% do PC. Aumento linear foi observado para os consumos de matéria orgânica (MO), proteína bruta (PB), extrato etéreo (EE) e carboidratos não-fibrosos (CNF). As digestibilidades totais de MS, MO, PB, EE e FDN aumentaram linearmente com o consumo de suplemento, o que não ocorreu com a eficiência microbiana, que não foi influenciada. No experimento 2 foram utilizados 19 animais, zebuínos, não-castrados com idade e pesos médios iniciais de 18 meses e 320 kg. As dietas foram: mantença, controle e ofertas diárias de 1, 2 e 3 kg do suplemento. Aumento linear foi observado para os consumos de MS, MO, PB, EE, FDN e CNF com o aumento das quantidades de suplemento. Consumos máximos de NDT, teor de NDT da dieta e ganho médio diário (GMD) foram estimados quando 2,88; 2,62 e 2,69 kg de suplemento foram ofertados. A quantidade de suplemento teve efeito quadrático sobre a digestibilidade de todos os nutrientes, mas não afetou a eficiência microbiana. A digestão total máxima de FDN é observada para um consumo aproximado de 1,5 kg de suplemento/dia, o que resulta em resposta ótima do ganho médio diário com taxa de ingestão de 400 g de PB.

Relation of net portal flux of nitrogen compounds with dietary characteristics in ruminants: A meta-analysis approach

Decrease of N intake (NI) with the aim of increasing efficiency of N utilization and decreasing the negative environmental effects of animal production requires assessment of the forms in which N is absorbed. A meta-analysis was conducted on 68 publications (90 experiments and 215 treatments) to study the effect of NI on net portal appearance (NPA) of nitrogenous nutrients [amino acids (AA), ammonia, and urea] in ruminants. In addition, the effect of several dietary energy and protein factors on this relationship was investigated. These factors were: dry matter intake; proportion of concentrate; diet concentrations and intakes of nonfiber carbohydrates and neutral detergent fiber (NDF); diet concentrations of total digestible nutrients (TDN) and crude protein; rumen-degradable protein and rumen-undegradable protein, as percent dry matter or percent crude protein. The effect of species and physiological stage was also investigated. Within-experiment analyses revealed that the NPA of AA-N and ammonia-N increased linearly, whereas the NPA of urea-N decreased (or recycling of urea-N increased) linearly with NI. Besides NI, many significant covariates could be introduced in each NPA model. However, only TDN and neutral detergent fiber intake (NDFi) were common significant covariates of NI in each NPA model. In this database, ruminants converted 60% of incremental NI into NPA of AA-N with no species effect on that slope. However, at similar NI, TDN, and NDFi, sheep absorbed more AA-N than did cattle and dairy cows. On the other hand, species tended to affect the slope of the relationship between NPA of ammonia-N and NI, which varied from 0.19 for the sheep to 0.38 for dairy cows. On average, the equivalent of 11% of incremental NI was recycled as urea-N to the gut through the portal-drained viscera, which excludes salivary contribution, and no species difference was detected. Overall, at similar TDN and NDFi, sheep and cattle increased their NPA of AA-N relative to NI increment by a similar magnitude. The higher absorption of AA-N observed in sheep compared with cattle, at similar NI, TDN, and NDFi, might result from lower losses of AA through portal-drained viscera metabolism.

Forage Rice Yield and Quality Response to Harvest Timing and Nitrogen Management

Because forage rice (Oryza sativa L.) must be cost competitive with other forages, high dry matter (DM) and total digestible nutrient (TDN) yield are essential. To optimize forage rice production, it is important to maximize nutritional value in the leaf and stem rather than in the panicle because the hull restricts cattle's (Bos taurus) ability to digest rice grain. In particular, it is important to maximize TDN concentration and yield in the leaf sheath plus stem (stem) due to the high proportion of this component in the crop rather than in the leaf blade (leaf). The objective in this study was to evaluate the effects of timing of first harvest [95 or 116 days after transplanting (DAT) (booting or full heading stage, respectively)], N application rate (150 or 300 kg N ha−1), and N application method (100–0N method, applying N at 100 and 0% in the first and second crops, respectively; 67–33N method, applying N at 67 and 33%, respectively; 33–67N method, applying N at 33 and 67%, respectively) on TDN concentration and yield in double‐harvest of forage rice systems in southwestern Japan. With the 100–0N method, stem TDN yield in the second crop was 39 g m−2 lower when the first crop was harvested at 116 DAT than at 95 DAT. However, with the 100–0N and 67–33N methods, stem TDN yield in the first crop was 152 and 163 g m−2 higher when the first crop was harvested at 116 DAT than at 95 DAT, respectively. When the first crop was harvested at 116 DAT, stem TDN yield in the first crop was 152 and 161 g m−2 higher with the 100–0N and 67–33N methods than with the 33–67N method, respectively. In contrast, stem TDN yield in the second crop was 115 and 142 g m−2 higher with the 67–33N and 33–67N methods than with the 100–0N method, respectively. To obtain high stem TDN yield in total of the first and second crops, harvesting the first crop at full heading and applying 300 kg N ha−1 at 67 and 33% in the first crop and second crops, respectively, is effective. Management practices that increase forage quality will help southwestern Japan to be more sufficient in forage production.

Yield, chemical composition and chlorophyll relative content of Tanzania and Mombaça grasses irrigated and fertilized with nitrogen after corn intercropping

It was evaluated the effect of the absence and of application of three nitrogen doses (50, 100 and 200 kg ha-1of N) and four harvest times in the winter/spring season (from July to October) on dry mass yield (DMY), on the relative chlorophyll contents (ICF _ leaf chlorophyll index) and on the contents of total digestible nutrients (TDN), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin, and their respective correlations on Tanzania and Mombaça grasses after intercrop with corn in distroferric red latosol (Oxisol) soil as well. It was used a random block design, in split-plot with four replicates. The greatest DMY occured with the increase of photoperiod (from August), neverthless responses to nitrogen fertilization over cuts difered among the grasses. In an irrigated crop-livestock integration system under cerrado conditions, it is technically feasible the establishment of Tanzania and Mombaça grass intercroped with corn at sowing or if cover nitrogen fertilization is performed because even in the abscence of nitrogen fertilization, great satisfactory quantity of forage was produced, with average DMY of 2,000 kg ha-1 per cut during the highest shortage of roughage for animals (winter/spring). Nitrogen fertilization after corn harvest increases DMY and improves bromatologic composition of the grasses, as contents of chlorophyll and CP in winter/spring is increased, besides the increase of contents of TDN and a reduction on the contents of NDF and ADF until September. Leaf chlorophyll index can be used to estimate the DMY and CP content and as a marker of the need of nitrogen fertilization of Tanzania and Mombaça grasses submitted to cutting.

Produtividade e valor nutricional da silagem de híbridos de milho em diferentes alturas de colheita

Cinco híbridos de milho foram avaliados quanto à produtividade de matéria seca, ao valor nutritivo da silagem e à produtividade de leite. Os híbridos avaliados foram AS 32, AG 9090, CD 308, DKB 747 e P 30F87, colhidos em três alturas de corte: 15, 35 e 55 cm. O delineamento experimental foi em blocos casualizados com parcelas subdivididas e três repetições. Para confecção das silagens, utilizaram-se silos experimentais de PVC com 20 cm de diâmetro e 40 cm de altura. A produtividade de leite, por tonelada de silagem (eficiência alimentar) e por hectare, foi estimada pelo modelo Milk2006. A produtividade de forragem ensilável reduziu com o aumento da altura de colheita, com resultados de 14,6; 13,0 e 12,6 t/ha MS para as alturas de colheita de 15 cm, 35 cm e 55 cm, respectivamente. O híbrido de milho e a altura de colheita influenciaram a composição bromatológica das silagens, com exceção do teor de extrato etéreo (EE), que não foi influenciado pela altura de colheita. Ocorreu interação híbrido × altura de colheita para o teor de amido, a digestibilidade in vitro da MS e da fibra em detergente neutro (FDN) e o teor de nutrientes digestíveis totais (NDT). Houve efeito da altura de colheita sobre a eficiência alimentar, cujos valores médios foram de 1.226, 1.291 e 1.393 kg leite/t silagem nas alturas de colheita de 15, 35 e 55 cm, respectivamente. Observou-se também efeito do tipo de híbrido sobre a produtividade de leite e a eficiência alimentar, com melhores valores verificados para o híbrido DKB 747 colhido na altura de 55 cm. Ao elevar a altura de colheita, melhora-se o valor nutritivo da silagem sem prejudicar a produtividade de leite por hectare. O manejo da altura de corte não substitui a escolha de melhores híbridos para produção de silagem de alta qualidade e produtividade.