Acid Detergent Insoluble Nitrogen Content Research Articles

Fermentation characteristics of bedded pack barn dairy cattle manure on methane yield, carbon, and nitrogen content in solid-state anaerobic digestion.

This study aimed to estimate the fermentation characteristics of bedded pack barn dairy cattle manure (BDCM) in terms of methane yield, fibrous material, and nitrogen content in batch solid-state anaerobic digestion (SSAD). SSAD was performed in triplicate using a 1,400 ml polypropylene bottle at a constant temperature of 39 °C until less than 1% methane was produced. The cumulative methane content of BDCM was 142.5 N mL/g volatile solids (VSs). The methane content rapidly increased for 18 days, reaching 63.4 ± 4.6% until the end of the experiment. The ultimate biodegradability and total VS removal of BDCM were 23.1 and 19.0%, respectively. The slopes of the non-fibrous and hemicellulose carbon fractions, and acid detergent insoluble carbon by digestion time were −0.174 (p < 0.001), −0.141 (p = 0.003), and −0.051 (p < 0.001), respectively. The non-fibrous and hemicellulose nitrogen fraction contents quadratically decreased during SSAD (p = 0.001 and p = 0.008). No significant decrease was observed in the acid detergent insoluble nitrogen content (p = 0.840). The results of the present study provide basic data on the digestion characteristics of BDCM and could help determine fermentation conditions in the anaerobic digestion of BDCM.

Effects of Applying Lactic Acid Bacteria and Molasses on the Fermentation Quality, Protein Fractions and In Vitro Digestibility of Baled Alfalfa Silage

Alfalfa sometimes cannot be harvested in time due to the rainy season. To improve the fermentation quality, protein quality and digestibility of alfalfa silage harvested late, Lactobacillus plantarum (LP) and molasses were applied in an actual production process in this study. Alfalfa harvested at the full bloom stage was ensiled with (1) distilled water (control), (2) 1 × 106 colony-forming units LP/g fresh matter, (3) 15 g molasses/kg fresh matter (M) or (4) LP + M (LPM) for 55 days. Alfalfa ensiled with LP and/or molasses showed significantly lower pH and ammonia nitrogen contents than the control silage (p &lt; 0.05). All additive treatments decreased nonprotein nitrogen contents and preserved more true protein (p &lt; 0.05). However, molasses increased the acid detergent insoluble nitrogen content in the protein fractions (p &lt; 0.05). The LP significantly improved the maximal cumulative gas production and the maximum gas production rate (p &lt; 0.05) in the in vitro trial. Finally, both LP and molasses improved the neutral detergent fiber digestibility of the alfalfa silage (p &lt; 0.05). The LP and molasses improved fermentation quality and digestibility and preserved more true protein in baled alfalfa silage harvested late in an actual production process. The LP utilized the excessive molasses and partially ameliorated its negative effects of causing higher acid detergent insoluble nitrogen content.

Effect of fermented spent instant coffee grounds on milk productivity and blood profiles of lactating dairy cows.

ObjectiveThis study was conducted to evaluate the fermentation characteristics under low mesophilic temperature of spent instant coffee ground (SICG) and to estimate the effect of fermented SICG (FSICG) as alternative feed ingredient on milk productivity of dairy cows.MethodsIn the fermentation trial, fermentation of SICG was performed to investigate changes in characteristics using the microbial mixture (Lactobacillus plantarum, Saccharomyces cerevisiae, and Bacillus subtilis = 1:1:1) for 21 days at 20°C under anaerobic conditions. Molasses was added at 5% of dry mass. In the animal trial, eighteen Holstein Friesian cows were used to evaluate the nutritive value of the FSICG which was fermented for 14 days under the same condition as the fermentation trial.ResultsIn the fermentation trial, the dry matter (DM) and organic matter content linearly decreased with fermentation time (p<0.001 and p = 0.008, respectively). The acid detergent insoluble nitrogen content linearly decreased with fermentation time (p = 0.037). The microorganism counts linearly increased for Lactobacillus plantarum, Saccharomyces cerevisiae, and Bacillus subtilis across fermentation time (p<0.001). In the animal trial, the DM intake of the control and FSICG treatment were not significantly different, as were milk yield, 4% fat corrected milk, fat-protein corrected milk, and feed to milk conversion content. Fat, protein, lactose, non-fat solids, milk urea nitrogen, and somatic cell counts were also not significantly different in milk composition between treatments.ConclusionFSICG should be considered a sufficient substitute for cottonseed as a feed component, and 5% DM of a dietary FSICG level was appropriate for dairy cow diets.

The acid detergent insoluble nitrogen (ADIN) analysis overestimates the amount of N associated to acid detergent fibre

The acid detergent insoluble nitrogen (ADIN) fraction of feeds is usually assumed to be indigestible, and some feeding systems for ruminants use the ADIN analysis as a measure of nitrogen (N) availability. In a preliminary study conducted with 3 different feeds, we observed lower 15N abundance in ADIN compared with that in both total N and neutral detergent insoluble N (NDIN). Based on these results, we hypothesized that ADIN analysis overestimates the amount of N associated to acid detergent fibre (ADFom) due to N-contamination from cetyltrimethylammonium bromide (CTAB), a reagent used in the ADFom analysis. The objective of this work was to verify lower 15N abundances of ADIN than of total N and NDIN in different feeds, and to assess the magnitude of ADIN contamination. Samples from one corn crop (aerial biomass, grain and root) and two sunflower crops (SF; aerial biomass and seeds) were analysed for 15N abundance and content of total N, NDIN and ADIN. Samples had been 15N-labelled by fertilizing with either 15NH4NO3 or NH415NO3, and there were three replicates per type of sample. The 15N-abundance of total N and NDIN was similar (P > 0.05) for all samples, whereas that of ADIN was lower (P < 0.001 to 0.037) than values for total N and NDIN for all samples, excepting for SF seeds from one crop. Estimates of N-contamination of ADIN from CTAB were not affected by the fertilizer used to label N (P ≥ 0.207), and values (g/g) ranged from 0.129 for corn grains to 0.447 for corn aerial biomass. N-contamination of ADIN was positively correlated with neutral detergent fibre (aNDFom), ADFom, hemicelluloses and cellulose content (P < 0.001; r = 0.770 to 0.905; n = 18 and 22 for corn and SF, respectively), and negatively (P < 0.001 to 0.048) with ADIN content (expressed as proportion of ADFom). The negative correlations (P < 0.001) between N-contamination of ADIN and lignin (Lignin (sa))/ADFom ratio observed for all samples would indicate that N-contamination of ADIN was reduced by cell wall lignification. In conclusion, the results showed that the use of CTAB in the ADFom analysis resulted in increased ADIN values, and therefore overestimated the amount of N associated to ADFom, questioning the use of ADIN as a parameter indicative of N availability. The possibility of replacing CTAB by a N-free reagent in the ADFom analysis should be explored.

Nutritive value and fermentation quality of palisadegrass and stylo mixed silages.

The nutritive value and fermentation quality of palisadegrass (Brachiaria brizantha cv. Xaraes) and stylo (Stylosanthes capitata×S. macrocephala cv. Campo Grande) mixed silages were evaluated. The experiment was analyzed in a factorial scheme (5×2) in a completely randomized design using increasing levels of stylo (0, 25, 50, 75 and 100% on a fresh matter basis) on palisadegrass silages, with and without microbial inoculants (MI). With the increased ratio of stylo in mixed silages, dry matter (DM), crude protein (CP), acid detergent fiber (ADF), and lignin content increased in silages. The presence of MI promoted lower DM content, and higher neutral detergent fiber corrected for ash and protein, ADF and lignin content. The acid detergent insoluble nitrogen content and the lactic acid bacteria populations were not affected by treatments. The invitroDM digestibility was affected by the interaction of levels of the stylo and MI. The pH, NH3 -N/total nitrogen and butyric acid concentrations decreased with increasing levels of stylo. Better nutritive value and quality of fermentation was found in the silage containing higher proportions of this stylo mixed with palisadegrass. The microbial inoculant evaluated did not alter the nutritive value or quality of the fermentation of the silages in this experiment.

Nutritional Characteristics of Available Feed Resources in Maradi Area of Niger

The aim of this study was to determine the nutritive value of feeds and to determine the effect of urea treatment on roughages. Straws, legumes and concentrates were collected in the dry season. Straws were millet stover, sorghum stover, Diheteropogon hagerupii, Eragrostis tremula and Schizachyrium exile; forage legumes were groundnut haulms and cowpea husk; concentrates were wheat bran, millet bran and cottonseed cake. Samples of straws and cowpea husk were either untreated or treated with urea. Feeds were analyzed for DM, OM, N, NDF, ADF, ADL and acid detergent insoluble nitrogen (ADIN). Degradability characteristics were determined using two Jersey cows. Cereal straws showed significant (P<0.001) variation in the fibre fractions and N content. Urea treatment of straws increased (P<0.001) N and ADIN content. Forage legumes had different (P<0.01) NDF and N. Urea treatment of cowpea husk increased (P<0.001) N. Concentrates differed (P<0.001) in N, and fibre. Straws had different (P<0.001) soluble fraction (wash), effective degradability (ED); urea treated straws had higher (P<0.001) ED. Forage legumes affected (P<0.01) solubility and ED, while treating cowpea husk decreased (P<0.05) ED. Concentrate affected (P<0.001) N degradability and ED. Effective degradability of DM and OM varied (P<0.001) within concentrates. These findings suggest that consideration of nutritional quality should be taken when formulating diets for ruminants in the study areas.

Determination of nutrient content and digestibility characteristics ofPrangos ferulacea (L.) on grazing lands of Eastern Anatolia

The aim of this study was to compare nutrient content, and in situ protein and organic matter degradation kinetics of Prangos ferulacea (L.) (locally called helis), a naturally growing plant on the top of Mount Artos, with those of alfalfa. P. ferulacea plants used in the study were collected from three different parts of Mount Artos in Van Province over two years. While organic matter content and in vitro organic matter digestibility of P. ferulacea were significantly higher, neutral detergent fiber, acid detergent fiber, and acid detergent insoluble nitrogen contents were significantly lower compared with those of alfalfa (P 0.05). It can be concluded that P. ferulacea has a better nutrient quality compared with even high quality alfalfa based on nutrient contents and digestibility values, and therefore substitution of alfalfa by P. ferulacea in the diet of ruminant animals is feasible.

Evaluación forrajera de leguminosas tropicales: Composición química, degradabilidad in vitro y selectividad ingestiva por bovinos y caprinos.

Se realizaron tres ensayos para determinar sucesivamente la composición química, la degradabilidad in vitro y la selectividad ingestiva de las leguminosas tropicales (LT) Stylosanthes guianensis (Estilosantes; SG), Cajanus cajan (Gandul; CC) y Arachis glabrata (maní forrajero; AG). El análisis químico incluyó las fracciones: materia orgánica e inorgánica (MO, MI), proteína bruta (PB), fibra detergente neutro y ácido (FDN, FDA), hemicelulosa, celulosa, lignina y nitrógeno insoluble en detergente ácido (NIDA) en muestras de planta completa y de componentes botánicos (tallo y hoja) de cada LT. Se determinó la degradabilidad in vitro de materia seca aparente y verdadera (DIVMSA y DIVMSV) en muestras de cada forraje mediante incubación durante 48 h con inoculo ruminal bovino y caprino. En una prueba de cafetería durante un periodo de 1 h, se observó la selectividad ingestiva de las tres LT por bovinos y caprinos, expresada mediante una escala cualitativa: ninguna, baja, mediana o alta. Se utilizó un heno comercial de gramíneas (HG) como criterio comparativo. En composición química, AG presentó un menor (P &lt; 0.05) contenido de MO y mayor de MI que CC, SG y HG (P &lt; 0.05). En las tres LT, el contenido de PB fue mayor (P &lt; 0.05) y el de FDN menor (P &lt; 0.05) que en HG. Entre las LT, la concentración de PB fue mayor (P &lt; 0.05) en AG que en SG o en CC, mientras el porcentaje de FDN fue similar entre especies. El contenido de FDA y celulosa fue menor (P &lt; 0.05) en AG que en CC o en SG, pero el contenido de hemicelulosa fue mayor (P &lt; 0.05). El contenido de lignina fue menor (P &lt; 0.05) en HG que en las LT, mientras que CC presentó la mayor (P &lt; 0.05) concentración de NIDA entre los forrajes evaluados. El contenido de PB en las hojas de las tres LT fue mayor de 20%. El contenido de FDN fue menor (P &lt; 0.05) en hojas de CC que en AG y SG, pero la FDA fue de mayor concentración (P &lt; 0.05) en SG que en AG y CC. Las hojas de AG tuvieron mayores valores (P &lt; 0.05) de hemicelulosa que CC y SG pero menores (P &lt; 0.05) de celulosa. El contenido de lignina fue similar (P = 0.05) en las hojas de las tres LT, mientras las hojas de CC presentaron un mayor (P &lt; 0.05) contenido de NIDA. El contenido proteico fue menor (P &lt; 0.05) en tallos de CC que en los de AG y SG. El contenido de FDN y sus fracciones (FDA, hemicelulosa y celulosa) fue menor (P &lt; 0.05) en los tallos de AG que en los de SG y CC. Los tallos de CC y AG presentaron los mayores contenidos de lignina y NIDA, respectivamente. Al usar ambos tipos de inóculos la DIVMSA y DIVMSV fue, en orden descendente, mayor (P &lt; 0.05) en AG que en SG, HG y CC. En el ensayo de cafetería, AG y HG presentaron una mayor selectividad ingestiva por bovinos y caprinos que SG y CC. Estos resultados demuestran que AG tiene un mayor potencial forrajero que SG y CC basado en su contenido de nutrientes, degradabilidad in vitro y selectividad ingestiva. Sin embargo, las tres especies de LT tienen cualidades que las hacen alternativas interesantes para utilizarse como parte integral en sistemas de alimentación de rumiantes en el trópico.

CARACTERÍSTICAS QUÍMICAS E FERMENTATIVAS DO CAPIM-ELEFANTE ENSILADO COM NÍVEIS CRESCENTES DE SUBPRODUTO DA AGROINDÚSTRIA DO CAJU

Nutritive value of silages of Elephant grass (Pen-nisetum purpureum, Schum.) mixed with 0; 3.5%; 7.0%; 10.5% and 14.0 % of dehydrated by product from juice industry of cashew fruit (Anacardium occidentale, L) (DBC) was determined. A randomized design was used with four replicates. Silages were opened after 65 days and samples taken for analysis of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose HCEL), cellulose (CEL), lig-nin (LIG), crude energy (CE), ash, neutral detergent inso-luble nitrogen (NDIN) and acid detergent insoluble nitro-gen (ADIN). Were also analyzed, pH, ammonia nitrogen and organic acids (lactic, acetic, butyric and propionic). Regarding fermentative parameters, there was an expected decrease in pH and the increasing levels of DBC did not affect the concentrations of N-NH3/NT and organic acids. It is concluded that dehydrated cashew by product can be ensiled along with Elephant grass without altering its fer-mentative characteristics. On the other side, the increased cell walls and ADIN contents of the silage may affect its nutritional value. Key-words: Cashew byproducts, nutritive value, tropical grass.

Digestibilidade dos compostos nitrogenados insolúveis em detergente ácido em bovinos manejados em pastagem de capim-braquiária

Objetivou-se neste estudo avaliar as digestibilidades total e parcial dos compostos nitrogenados insolúveis em detergente ácido (NIDA) em bovinos em pastejo. Foram utilizados cinco novilhos mestiços Holandês x Zebu (24 meses de idade e 304 kg de PV), canulados no esôfago, rúmen e abomaso, manejados em cinco piquetes de Brachiaria decumbens (0,34 ha), recebendo ou não suplementação com concentrado. O experimento foi realizado em quatro períodos experimentais de 21 dias, entre agosto e novembro de 2000. A avaliação da forragem selecionada pelos animais foi feita em amostras de extrusa esofágica e a estimativa do consumo e dos fluxos fecais e abomasais de MS e NIDA, foram estimados por intermédio de indicadores interno e externo. A avaliação estatística da digestibilidade do NIDA foi conduzida por ajustamento de equação de regressão linear, desconsiderando o parâmetro intercepto e utilizando-se como variáveis independente e dependente as estimativas de influxo e efluxo de NIDA, respectivamente. Os desvios do coeficiente de regressão a partir do valor paramétrico 1,0 foram considerados estimativas de digestibilidade. A comparação entre o consumo e os fluxos abomasal e fecal de NIDA indicou haver digestibilidade desta fração em nível total, atribuída exclusivamente a eventos intestinais (30,7%), uma vez que não foi observada digestibilidade no compartimento ruminal. Esse comportamento indica que o teor de NIDA de um alimento é somente indicador, e não preditor, da digestibilidade potencial dos compostos nitrogenados totais.

PH e amônia ruminais, relação folhas: hastes e degradabilidade ruminal da fibra de forrageiras tropicais

Este experimento foi realizado com o objetivo de avaliar o pH e a concentração de nitrogênio amoniacal (N-NH3) do líquido ruminal coletado 3, 6 e 12 horas após a alimentação de quatro novilhos mestiços Europeu-Zebu, providos de cânulas ruminais permanentes, assim como a relação folhas:hastes e as degradações ruminais in situ da fibra em detergente neutro (FDN) e da fibra em detergente ácido dos folíolos de três leguminosas tropicais: leucena (Leucaena leucocephala (Lam.) de Wit), guandu (Cajanus cajan (L.) Millsp.) e soja perene (Neonotonia wightii) e das folhas de outras duas forrageiras tropicais: rami (Boehmeria nivea (L.) Gaudich) e mandioca (Manihot esculenta Crantz). Amostras de 3 g de guandu, soja e rami ou 5 g de leucena e mandioca foram incubadas no rúmen dos animais por períodos de 3, 6, 12, 18, 24 e 48 horas. O delineamento experimental utilizado foi o de parcelas subdivididas, em que as parcelas eram representadas pelas forrageiras e as subparcelas, pelos seis horários de incubação do material no rúmen, sendo os quatro animais considerados blocos. Os valores de pH e N-NH3 no rúmen provavelmente permitiram adequada fermentação microbiana. As relações folhas:hastes das forrageiras variaram entre si e em relação à literatura. As degradabilidades efetivas (DE) da FDN das forrageiras avaliadas foram em torno de 50%, sendo menores para os folíolos de guandu (19,25%), que também demonstraram as menores taxa de degradação (2,5%/h) e degradabilidade potencial (57,76%). Os valores de DE da FDN foram negativamente correlacionados aos conteúdos de nitrogênio insolúvel em detergente ácido das forragens (r = -0,986). O guandu foi a pior forrageira quanto ao aproveitamento dos componentes estruturais.

Determination of Total, Volatile and Acid Detergent Insoluble Nitrogen in Silage by Sequential Injection

This work proposes a sequential injection procedure to determine the total, volatile and acid detergent insoluble nitrogen content in silage. An ammonium tubular selective electrode coupled to a sequential injection manifold was used as detector to accomplish the potentiometric determinations made after on-line ammonia diffusion in alkaline medium through a Teflon membrane and NH3/NH4+ conversion. Different sample treatments, taking into account the species to be analyzed, were adopted to apply the proposed procedure to silage samples. An analytical frequency of 30 samples h-1 and a detection limit of 3.0 mg N l-1 were observed when 300 µl of 3.0 mol l-1 NaOH solution and a sample volume of 150 µl were employed. The use of the proposed procedure allowed the automation of the determinations, low sample and reagent consumption and small waste production, emphasizing the versatility and potentiality of the flow methods when applied to animal nutrition laboratories.

Feeding value for lambs of rapeseed meal arising from biodiesel production

AbstractMeals prepared from low glucosinolate rapeseed screenings (SCREEN) and from seed which had heated during storage (HEAT) were compared against commercial rapeseed meal (COM) for feeding value. Oil, crude protein (CP) and acid-detergent insoluble nitrogen contents in SCREEN, HEAT and COM, respectively, were (g/kg): 118, 246 and 13; 227, 315 and 436; and 17, 64 and 21.in situdry matter (DM) and protein disappearance rates, soluble protein fraction and effective rumen degradability of protein (EDCP) were lower (P&lt; 0·05) in HEAT than in SCREEN or COM. Comparing oil-extracted meals in situ, EDCP of HEAT was lower (P&lt; 0·05) than EDCP of SCREEN or COM but protein and DM disappearance rates of HEAT were only lower (P&lt; 0·05) than those of SCREEN. Four isonitrogenous barley-based diets (150 g/kg CP, DM basis), containing SCREEN, HEAT, COM or COM supplemented with rapeseed oil (OIL), were given to lambs. For DM, organic matter and neutral-detergent fibre apparent digestibilities, the diets ranked SCREEN &gt; HEAT = OIL &gt; COM (P&lt; 0·05). Digestion and retention of nitrogen were lower (P&lt; 0·05) in lambs given HEAT than in lambs given other diets. Food efficiency of lambs given HEAT was improved (P&lt; 0·05) as compared with lambs given SCREEN or COM. Dressing proportions were higher (P&lt; 0·05) with HEAT, SCREEN and OIL diets than with COM. Other than minor changes in fatty acid composition of subcutaneous fat with HEAT and OIL, carcass traits were not altered by treatment. Feeding SCREEN or HEAT did not adversely affect animal performance or food utilization.

Influence of dry heat treatment of canola meal on site and extent of nutrient disappearance in ruminants

A study was conducted to determine the effects of temperature and duration of heating (125 or 145 °C for 10, 20 or 30 min) on ruminal, intestinal and total tract disappearance of the dry matter (DM) and crude protein (CP) fractions of canola meal. Two steers fitted with rumen and duodenal cannulas were utilized. The effects of heating on ruminal disappearance of DM and CP were determined by incubating samples in the rumen for 2, 4, 6, 8, 12, and 24 h. Partitioning DM and CP disappearance between the rumen, intestines (small and large) and total tract was accomplished using the mobile nylon bag technique. Relative to the unheated control meal, heating at 125 or 145 °C reduced ( P < 0.05) ruminal DM and CP disappearance. Relative to the control, no effects of heating to 125 °C were observed on intestinal DM or CP disappearance with the exception that samples heated for 20 or 30 min and incubated in the rumen for 24 h had higher ( P < 0.05) intestinal DM disappearance values. Heating to 145 °C reduced ( P < 0.05) intestinal DM disappearance relative to the control, particularly for samples heated for 30 min. Heating to 145 °C reduced ( P < 0.05) intestinal CP disappearance across all rumen incubation times. No differences between the control and meals heated to 125 °C were found in total tract DM and CP disappearance, indicating no negative effects of heating to 125 °C on nutrient digestion. Heating to 145 °C reduced ( P < 0.05) both total tract DM and CP disappearance. Acid detergent insoluble nitrogen content of the treated meal was negatively related to intestinal ( r 2 = 0.78) and total tract ( r 2 = 0.82) CP disappearance. It is concluded that heating CM to a temperature of 145 °C will reduce ruminal and total tract availability of the DM and CP fractions. Heating to 125 °C for 10, 20 or 30 min will reduce rumen disappearance of both DM and CP but will not significantly reduce the disappearance of CP over the total tract of the ruminant. These results indicate that short duration heating of canola meal to 125 °C, is an effective method of increasing rumen undegradable protein content without impairing intestinal digestibility.

Effects of roasting of lupins ( Lupinus albus) and high protein variety of soybeans ( AC Proteus) on chemical composition and in situ dry matter and nitrogen disappearance in dairy cows

The effects of roasting of lupins or soybeans were evaluated for chemical composition and in situ rumen degradability. Sweet white lupins ( Lupinus albus) and a high protein variety of soybeans, AC Proteus (HPSB), were roasted in an electric roaster at a temperature of 300°C with a residence time of 1, 2, 3, or 4 min. Raw and roasted samples were analysed for total nitrogen, acid detergent insoluble nitrogen (ADIN) and protease insoluble nitrogen (PIN), and available rumen by-pass protein (RBP) was determined. In situ degradability of dry matter (DM) and nitrogen (N) was determined using Dacron bags in the rumen of three ruminally cannulated dry cows. Soybean meal (SBM) served as a control treatment. Total N content of lupins and HPSB was not affected by roasting. Heat treatment increased linearly ( P < 0.02) the PIN content of lupins and HPSB. ADIN content of lupins and HPSB significantly increased with increasing roasting time from 1 to 4 min. Available RBP increased more in roasted HPSB than in roasted lupins with increasing roasting time. SBM had lower available RBP than roasted lupins or HPSB. Roasting significantly ( P < 0.01) reduced effective degradation of DM and N in roasted lupins and HPSB at a calculated outflow rate in the rumen of 0.06 h −1. The effective degradation of N of HPSB or lupins at 4 min roasting was 10 percentage units lower than SBM. It can be concluded that roasting of lupins or soybeans is a useful tool to increase available rumen by-pass protein and to reduce the effective degradation of N in the rumen of dairy cows.

Ruminal degradation of alfalfa protein as influenced by sodium hydroxide and heat treatment

Effects of sodium hydroxide (NaOH) and heat treatment of alfalfa on the degradation of protein in the rumen was investigated in relation to the changes of nitrogenous compounds. Fresh alfalfa was treated with 0, 1.16, 2.32 or 4.64 g NaOH per 100 g dry matter (DM) and then subjected to freeze-drying, or oven-drying for 24 h at 60 or 120°C. Both NaOH and heat treatment produced lysinoalanine at increasing rate with level of treatment to reach a maximum value of 238 mg per 100 g protein. Both treatments also increased neutral detergent insoluble nitrogen (NDIN) according to the increase in level of treatment. Acid detergent insoluble nitrogen (ADIN) was not affected by NaOH treatment but was significantly increased by heating at 120°C. Both NaOH and heat treatment modified protein into being less soluble and more slowly degradable in the rumen, but heating showed greater effects than NaOH treatment. The proportion of potentially degradable protein was little influenced by the treatments. Both NaOH and heat treatment decreased the rate of protein degradation, but significant differences were detected only with the highest level of treatment (4.64 g NaOH per 100 g DM or 120°C). Correlation coefficients of lysinoalanine, NDIN and ADIN content with rate of protein degradation in the rumen were −0.716, −0.950 and −0.834, respectively. These results suggest that lysinoalanine formation in protein by NaOH and heat treatment can make protein less susceptible to microbial degradation in the rumen, while protein-carbohydrate reaction enhanced the effects on protein degradation in this study.

Relationships among rate of passage of feed, dry matter intake and chemical components of several diets

Relationships among feed dry matter intake (DMI), rate of passage of feed through the rumen (ROP) and content of chemical components of feeds were determined to investigate the possibility of developing prediction equations for DMI and ruminal passage rates of digesta. ROP determined as exponential rate of marker decline in either feces (ROPf) or rumen contents (ROPr), DMI and body weight (BWt) of animals were determined using six mature steers in a 6 × 6 Latin square design experiment. Alfalfa hay (AA), orchard-grass hay (OG), alfalfa silage (AS), corn silage (CS), 70 + 30: cracked corn and OG (70G), and 70 + 30: barley straw and AA (70S) were used in the experiment. Chemical composition of feeds (protein, neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent insoluble nitrogen (ADIN) and lignin) was determined and, along with BWt of the steers, was regressed against DMI, while DMI was also included among the factors regressed against ROPf and ROPr. Even though animal factors, such as DMI and BWt, and feed factors, including the chemical components, were regressed against ROPf and ROPr, only protein and ADIN content in feed were significant factors included for ROPr (r2 = 0.358), while for ROPf, protein, ADIN and lignin content were the three significant factors (r2 = 0.362). However, DMI of the steers was predictable from the equation DMI (kg) = 15.52−0.080 NDF−0.101 ADF + 9.462 ADIN (as % of DM) (R = 0.84; P &lt; 0.0001; residual standard deviation (rsd) = 1.01) with an R2 value of 0.702, but accurate estimation of rate of passage from feed and animal factors requires more research. Key words: Prediction of rate of passage, chromium mordanted neutral detergent fibre, intake, steers, forages

A note on the use of the chicken to predict protein digestibility in the small intestine of sheep

The true digestibility of protein from diets containing one of the protein-rich foodstuffs, sunflower oil cake, cottonseed oil cake, maize gluten meal and fish meal, was determined in chickens and in the small intestine of sheep. With the exception of maize gluten meal, a close correlation was found between digestibility in the two species (r = +0·98; P &lt; 0·05) and in the sheep small intestine between the true digestibility of utilizable nitrogen and acid-detergent insoluble nitrogen content of the diet (r = -0·96; P &lt; 0·05).

Nitrogen Fractions of Alfalfa Silage from Oxygen-Limiting and Conventional Upright Silos

Alfalfa silage from oxygen-limiting (39 samples) and conventional upright silos (43 samples) sent to the Virginia Tech Forage Testing Laboratory from September 1984 to April 1985 were randomly selected and analyzed for dry matter, fiber, and nitrogen fractions. Crude protein and neutral and acid detergent fiber were not different for oxygen-limiting and conventional upright silo samples. Dry matter, and buffer-insoluble nitrogen, neutral and acid detergent insoluble nitrogen, and nitrogen insoluble in neutral but soluble in acid detergent, expressed as a percent of total nitrogen, were greater in silage from oxygen-limiting than from conventional upright silos. A greater percentage of samples from oxygen limiting silos had acid detergent insoluble nitrogen content greater than 15% compared with samples from conventional upright silos (35.9 vs. 14.0%).Regression equations were formulated for dry matter versus acid detergent insoluble nitrogen. Dry matter, dry matter squared, and dry matter cubed accounted for only 34 and 35% of the variation in acid detergent insoluble nitrogen in conventional upright and oxygen limiting silos, respectively. Other factors must be considered to predict accurately acid detergent insoluble nitrogen.

Nitrogen Fractions in Selected Feedstuffs

Nitrogen in selected feedstuffs was fractionated based on solubility in mineral solvents and detergent solutions. Six solvents with either a continuous mixing procedure at constant temperature or an intermittent mixing procedure at room temperature were compared for nitrogen solubility. Nitrogen solubility varied with type of solvent. Borate-phosphate buffer was more stable than other solvents. Borate-phosphate buffer had a correlation coefficient of .92 with insoluble nitrogen obtained with autoclaved rumen fluid. Insoluble nitrogens obtained by continuous or intermittent mixing techniques were not significantly different. The latter procedure is simple and avoids the need for special extraction equipment for estimation of nitrogen solubility. In most feedstuffs, a large fraction of soluble nitrogen was in the form of nonprotein nitrogen. Oats and peanut meal contained a significant amount of soluble true protein (43.3 and 24.3% of total nitrogen). Neutral detergent insoluble nitrogen and acid detergent insoluble nitrogen content of feed samples varied among feedstuffs and were not a constant proportion of neutral detergent or acid detergent fiber.