Tropical Grass Hay Research Articles

Consumo voluntario y digestibilidad de nutrientes de heno de gramíneas y leguminosas tropicales suplementadas con ensilaje de residuos de pescadería

Se realizaron dos experimentos con el objetivo de determinar el efecto de la suplementación con ensilaje de residuos de pescado tilapia (EP) preparado en silos de laboratorio con la adición de melaza de caña sobre el consumo voluntario y la digestibilidad de nutrientes, de heno de gramíneas tropicales (HG) (Digitaria eriantha, 80% y Urochloa maximun, 20%) y de heno de maní rizoma perenne (HMRP) (Arachis glabrata). En el ensayo experimental I se evaluaron tres tratamientos (T1 o Control = HG;T2= HG + EP a 0.45% del peso vivo (PV); T3= HG + EP a 0.90% del PV diariamente), mientras que en el ensayo experimental II se evaluaron los tratamientos (T1 o Control = HMRP; T2= HMRP + EP a 0.225% del PV; T3= HMRP + EP a 0.45% del PV diariamente). En ambos ensayos se utilizaron nueve carneros enteros distribuidos según un diseño de cuadrado latino 3X3. Los animales se sometieron a una etapa de adaptación a las dietas de ocho días y a un periodo de recolección de datos de seis días durante cada periodo. En el ensayo I, la suplementación con EP a carneros alimentados con HG aumentó linealmente (P < 0.05) el consumo voluntario y la digestibilidad de materia seca (MS) y también (P < 0.05) el consumo de proteína bruta (PB). En la digestibilidad de la PB hubo diferencias (P < 0.05) entre el control y los tratamientos con suplementación, pero T2 fue similar a T3 (P > 0.05). Por otro lado, la suplementación con EP no afectó (P > 0.05) la digestibilidad de la fibra detergente neutro (FDN), pero enT3 se redujo (P < 0.05) su consumo. Se concluyó que la suplementación de HG con EP al 0.90% del PV se presenta como la mejor alternativa. En el ensayo II, la suplementación con EP al 0.45% del PV aumentó (P< 0.05) la digestibilidad de la MS, mientras el aumento casi tan grande obtenido con EP al 0.225% del PV no alcanzó significación a P = 0.05 en carneros alimentados con HMRP. Sin embargo, la suplementación con EP no aumentó (P > 0.05) el consumo de MS, de PB ni de FDN. En cuanto a la digestibilidad de la PB se observaron diferencias entre el control y los demás tratamientos pero la de T2 fue similar a la de T3. La suplementación con EP no afectó la digestibilidad de la fibra (P > 0.05). Por lo tanto, en carneros alimentados con la leguminosa el menor nivel de suplementación es recomendable. Al comparar los tratamientos control de los dos ensayos, el consumo voluntario de MS, FDN y PB en forma de HMRP fue mayor que con HG. La leguminosa también presentó una mayor (P < 0.05) digestibilidad de la MS y PB.

Consumo y digestibilidad de gramíneas tropicales conservadas y el efecto de la suplementación con residuos fermentados de pescadería.

Se llevaron a cabo tres ensayos con carneros adultos con el objetivo de evaluar el consumo voluntario y digestibilidad in vivo de nutrientes, materia seca (MS), proteína bruta (PB) y fibra detergente neutro (FDN) de heno de gramíneas tropicales naturalizadas (HGTN) y ensilaje de sorgo (ES) con o sin suplementacion de residuos fermentados de la producción de filete de tilapia (RFPT) y lodos fermentados de la industria atunera (LFIA). En el primer ensayo metabólico se compararon dietas de los dos forrajes sin suplementación. Cuatro carneros criollos adultos se distribuyeron a los tratamientos según un diseño completamente aleatorizado (DCA). Se observó un mayor consumo voluntario (P < 0.05) por parte de los animales alimentados con HGTN. La digestibilidad aparente también fue mayor para HGTN que para ES, pero estas diferencias no alcanzaron significación estadísticas. En el segundo y tercer ensayo metabólico se evaluó el efecto de la adición de RFPT y LFIA, respectivamente, como suplementos a dietas básales de heno de GTN y ES. El RFPT y LFIA se aplicaron a niveles de 30% del consumo de MS esperado a base del peso vivo. En ambos experimentos, se utilizaron ocho carneros adultos distribuidos según un DCA. Al añadir RFPT y LFIA a la dieta de los carneros aumentó (P < 0.05) el consumo voluntario de MS y PB en relación al consumo obtenido con el forraje solo, pero se alcanzaron mayores consumos de MS (P < 0.05) con HGTN que con ES. En las dietas basadas en ES la suplementacion con ambos residuos fermentados de pescadería tendió a aumentar la digestibilidad aparente de la MS, PB y FDN. En las dietas basadas en HGTN, ambos residuos aumentaron la digestibilidad aparente de la PB, mientras el LFIA aumentó la digestibilidad aparente de la MS. El único efecto negativo observado en esta dieta fue la disminución en la digestibilidad aparente de FDN cuando se suplemento con LFIA.

Supplementation strategies to improve efficiency of rumen microbial protein synthesis on cattles fed with tropical grass hay

This experiment aimed at increasing rumen microbial protein supply into intestine through ration manipulation. Four Santa Gertrudis steers with a mean liveweight (W) of 218 (±5.6) kg were used in a latin square design (4 x 4) to observe the effect of four diets on the efficiency of rumen microbial protein synthesis (E MPS ). The steers were given pangola grass hay (8.5% protein) as the basal diet. The treatments were 1) pangola grass hay alone (KON), 2) pangola grass hay + 19 g urea/kg dry matter (DM) hay (URE), 3) as for treatment URE + a supplement mix at 0.5% W (SUP), and 4) as for treatment SUP + salt at 0.15% W (SUG). Urea was added into the hay to support a theoretical E MPS of 160 g MCP/kg digestible organic matter (DOM) whereas supplement mix contains fast, medium, and slow rumen fermentable energy and protein to synchronise energy and protein release in the rumen. Salt was added to alter passage rate of digesta. Addition of urea alone or with supplement mix increased E MPS significantly compared to KON (77 g MCP/kg DOM) but no difference between URE (119 g MCP/kg DOM) and SUP (110 g MCP/kg DOM). Addition of salt into supplement mix increased E MPS by 84% (140 g MCP/kg DOM). It might be concluded that rumen degradable protein (RDP) was deficient in steers fed low quality grass hay hence urea supplementation significantly increased E MPS to a similar extent as that of the supplement mix formulated to have a synchrony in protein and energy release. Increasing fluid dilution rate, by adding salt, also had a dramatic affect on E MPS as observed in treatment SUG. It increased up to the level suggested in the International feeding standards. Key Words: Microbial Protein, Soluble Protein, Dilution Rate, Supplement, Tropical Grass

Modificações na técnica de digestibilidade in vitro para avaliar forragens de baixa qualidade

Dois experimentos foram desenvolvidos no Departamento de Zootecnia da Universidade Federal de Santa Maria (UFSM), para estudar modificações na técnica de digestibiüdade in vitro para avaliar forragens de baixa qualidade. O experimento I consistiu na determinação dos coeficientes de digestibilidade in vivo da matéria orgânica (MO), envolvendo 10 fenos de gramíneas tropicais e 2 palhas provenientes da colheita de grãos. No experimento II, determinaram-se os coeficientes de digestibilidade in vitro através da técnica proposta por TILLEY and TERRY (1963), tratamento M1- 48 horas de incubação com inóculo ruminal (fermentação microbiana) + 48 horas de incubação com pepsina (fermentação enzimática) e estudaram-se modificações sobre esta, denominadas: M2- prolongação no período de incubação (de 48h para 96h), com renovação do inóculo ruminal, após 48h de incubação, (adição de novo inóculo sobre a fase sólida das amostras, após centrifugação e desprezada a fase líquida); M3- 96h de incubação com inóculo ruminal, com reinoculação, após 48h de incubação, (adição de novo inóculo sobre as amostras, sem a centrifugação e retirada da fase líquida); M4- 96h de incubação com inóculo ruminal diluído, com renovação do inóculo; M5- 96h de incubação com inóculo ruminal diluído, com reinoculação; M6- 96h de incubação com inóculo ruminal, renovação do inóculo e prolongação no período de incubação com pepsina (de 48h para 72h) e M7- 96h de incubação com inóculo ruminal, reinoculação, digestão com pepsina de 72 horas. Foi efetuada a análise de correlação entre as médias dos coeficientes de digestibilidade in vivo e a digestibilidade in vitro das modificações, para todas as forragens e a análise de regressão sobre o tratamento que apresentou correlações altas e significativas. Pelos resultados obtidos, pode-se constatar que o método in vitro de TILLEY and TERRY (1963) não apresentou boa precisão para estimar a digestibilidade de forragens de baixo valor nutritivo e que, dentre as modificações testadas, a com 96h de fermentação com líquido de rúmen (LR), com reinoculação do LR após 48h de incubação + 48h com pepsina (M3), foi a que demonstrou melhor eficiência para estimativa da digestibilidade.

Inclusión de leguminosas forrajeras en dietas basadas en gramíneas tropicales. II. Consumo voluntario y digestibilidad aparente de nutrimentos

Se estudió el efecto de la inclusión de una leguminosa forrajera (Leucaena leucocephala o Stylosanthes guianensis) sobre el consumo voluntario de materia seca (CMS) y la digestibilidad aparente de la materia seca (DMS), proteína cruda (DPC), fibra detergente neutro (DFDN) y fibra detergente acida (DFDA), de corderos alimentados con dietas basadas en un heno comercial de gramíneas. Ocho corderos adultos distribuidos aleatoriamente en jaulas individuales provistas de comederos y bebederos se alimentaron con dietas que difirieron en la especie y nivel (10, 20 y 40%) de leguminosa. Como porción basal y ración testigo se utilizó heno comercial de gramíneas compuesto principalmente de pasto buffel (Cenchrus ciliaris L.) y pajón (Dicanthium annulatum). El CMS aumentó (P < 0.05) al incrementarse el nivel de leguminosa en la dieta (1.00, 1.30 y 1.46 kg/d con 10, 20 y 40% de leguminosa, respectivamente). Entre las dos leguminosas evaluadas, el CMS fue mayor al incluir Stylosanthes guianensis (1.30 kg/d) que al incluir Leucaena leucocephala (1.16 kg/d) en la mezcla. Hubo efectos significativos de la especie de leguminosa sobre la digestibilidad de los principales componentes de la dieta, a excepción de la proteína cruda. Los valores promedios, para las dietas con Leucaena leucocephala y Stylosanthes guianensis, fueron; DMS, 61,88 y 59.36; DPC, 71.37 y 70.26; DFDN, 62.57 y 58.33; y DFDA, 47.71 y 41.48%, respectivamente. No se observaron efectos significativos sobre la digestibilidad al incorporar las leguminosas al 10 ó 20% de la materia seca (valores promedio: DMS, 59.3; DPB, 70.5; DFDN, 59.1; y DFDA, 43.0%). Sin embargo, al incorporar las leguminosas al 40% de la materia seca, se obtuvo un incremento en DMS (63.8%), DFDN (63.5%) y DFDA (48.6%), pero no en DPB (71.1%). En conclusión, la utilización de leguminosas como complemento de gramíneas en dietas para rumiantes puede ser de utilidad para incrementar la productividad, debido a un mayor consumo total de nutrimentos.

粗飼料の種類が黒毛和種母牛の飼料摂取量および採食,反芻行動に及ぼす影響

To determine effect of kinds of forage on feed intake and behavior of eating and rumination of Japanese Black cows, animals were given ad libitum of 8 kinds of forage such as alfalfa as legume hay, Italian ryegrass, perennial ryegrass, timothy, oats hays as temperate grass hay, bermudagrass, sudangrass as tropical grass hay, and rice straw. Dry-matter intake based on metabolic body size (g/kg0.75) was more than 100g/kg0.75 for legume hay, some temperate grass hays (timothy and oats hays), but 70g/kg0.75 for some temperate grass hays (Italian ryegrass and perennial ryegrass hays) and rice straw. Intake for tropical grass hays ranged from 80 to 90g/kg0.75. The time spent for eating ranged from 340 to 404min/day without any significant difference among forages. On the basis of dry-matter intake, however, animals spent less time for eating legume hay, some temperate grass hays (timothy, oats) and tropical hays than some temperate grass hays (Italian ryegrass, perennial ryegrass) and rice straw. The time spent for rumination was significantly different among forages, ranging from 369min/day for legume hay to 534min/day for a temperate grass hay (perennial ryegrass). The time spent for eating and ruminating did not always reflect the difference in dry-matter intake.

Net flux of nutrients across splanchnic tissues in sheep fed tropical vs. temperate grass hay of moderate or low qualities

Abstract Crossbred wethers (18 months old; 44 ± 0.7 kg body weight), with catheters in a hepatic vein, the portal vein and a mesenteric vein and artery, consumed ad libitum tropical or temperate grass hay each of three different qualities or stages of maturity. Splanchnic tissue energy consumption was similar among tropical grass diets but increased as quality of temperate grass declined. Portal-drained viscera oxygen consumption increased with increasing digestible energy intake and fecal neutral detergent fiber excretion. Energy available to extra-splanchnic tissues with highest quality grass was greater for temperate than for tropical grass because of lower splanchnic tissue energy consumption relative to digestible energy intake. Grass source, quality and nitrogen concentration did not significantly affect portal-drained viscera release of α-amino nitrogen. Hepatic uptake of α-amino nitrogen was greater for tropical than for temperate grass, presumably because of higher nitrogen concentration with greater hepatic ammonia nitrogen uptake. Glucose uptake by the portal-drained viscera was greater for tropical than for temperate grass, and the potential contribution of propionate to hepatic glucose release tended to be greatest for grass highest in quality. Grass quality appears more important to achieve maximal energy availability to extra-splanchnic tissues with temperate than tropical grass.

Alteration of supplement nitrogen:Sulphur ratio by increasing sulphate supplementation affects the rate rather than the extent of fibre degradation in cattle fed a matured tropical grass hay

AbstractThere is a need to understand how supplement N: S ratios can affect ruminal fermentation and ultimately, nutrient supply, in grazing animals. The following experiment was undertaken to describe the effect(s) of supplement N : S ratios upon the rate and extent of ruminal degradation of poor quality native pasture hay. Four rumen fistulated Brahman × Shorthorn (Drought master) steers, fed chopped Black Spear Grass hay, received either no intraruminal supplement, or urea plus sodium sulphate to give supplement N: S ratios of 23:1, 16:1, 11.5:1, 10:1 and 4:1. The level of urea supplementation was kept constant and maintained rumen ammonia concentrations in excess of 100 mg litre−1. No differences were observed in voluntary feed intake in response to different supplement N: S ratios. The extent of rumen fermentation as measured by the nylon bag technique and apparent organic matter digestibility in vivo were similar for supplement N : S ratios of 16:1 and lower, and total intake of digestible organic matter was maximal with a supplement N : S ratio of 10: I. Increasing levels of S supplementation were found to increase the rate of rumen fermentation.

Cane molasses and cottonseed meal supplementation of ammoniated tropical grass hay for yearling cattle.

Laboratory, digestion, and growth studies were used to evaluate liquid cane molasses (MOL) and(or) cottonseed meal (CSM) supplementation of ammoniated (4% of the forage DM) stargrass (Cynodon nlemfuensis Vanderyst var. nlemfuensis) hay. Ammoniation increased (P < .01) total N concentration (1.0 to 1.4% vs 1.7 to 2.8%) and in vitro digestion of OM, NDF, and ADF and decreased (P < .01) NDF concentration of stargrass hay. Two digestion (4 x 4 Latin square, 250-kg steers) and two growth (230-kg Brahman crossbred steers, seven to eight steers per pasture, three to four pastures per treatment, October through February) trials evaluated MOL and(or) CSM supplementation of ammoniated hay. Supplementation with CSM alone did not influence (P > .05) apparent digestibilities of OM or NDF, whereas supplementation with MOL either alone or with CSM increased (P < .05) apparent OM digestibility, but decreased (P < .05) apparent NDF digestibility. In the growth trials, hay intake was not affected (P > .05) by supplementation with CSM alone and was decreased (P < .05) by supplementation with MOL either alone or with CSM; however, total feed intake was increased (P < .05) by MOL supplementation. Cattle fed only ammoniated hay gained approximately .20 kg/d. In both trials, daily gain and gain/feed were improved (P < .05) by CSM (.39 to .47 kg; .062 to .071) or MOL (.34 to .35 kg; .047 to .048) supplementation. Improvements (P < .05) in daily gain (.54 to .76 kg) and gain/feed (.077 to .083) by supplementation with MOL plus CSM were additive to responses from supplementation with MOL or CSM individually.(ABSTRACT TRUNCATED AT 250 WORDS)

Ammoniation of Tropical Hays and Its Effect on Digestibility and Feeding Value

Rapid plant maturity and poor hay-curing conditions during the summer result in hay of poor quality and limited quantity in many humid tropical and subtropical areas. Treatment of low-quality, tropical-grass hay with anhydrous NH3 holds potential for improvement of nutritional value of livestock feed. Specific nutritive characteristics, which are potentially affected by ammoniation, differ among grass species. Effects of ammoniation (70 lb/ton) on the feeding value of hays of ‘Pensacola’ bahiagrass (Paspalum notatum Flugge), ‘Bigalta’ limpograss [Hemarthria altissima (Poir) Stapf and C.E. Hubb], and ‘Ona’ stargrass (Cynodon nlemfuensis Vanderyst var. nlemfuensis) were evaluated. Ammoniation increased crude protein content by 2.7 to 8.1 percentage units. Apparent digestibility was measured with six steers per treatment. Cattle were fed 2.2 lb of a soybean [Glycine max (L.) Merr.] meal-based concentrate plus hay at 85% of ad libitum intake. Ammoniation increased (P < 0.05) digestion coefficients for neutral detergent fiber (NDF), acid detergent fiber (ADF) and cellulose. Ammoniated and untreated bahiagrass and stargrass hays were fed to 60 Brahman crossbred (Bos taurus × B. indicus) heifers (472 lb) for 87 d in a growth experiment. Cattle were fed 4.9 lb of supplement daily plus hay ad libitum. Hay consumption and average daily gain (ADG) were similar for bahiagrass and star-grass. Ammoniation increased (P < 0.001) hay intake by 39% (7.5 vs. 5.4 Ib/d), ADG by 50% (1.2 vs. 0.8 Ib/d), and feed efficiency by 17% (10.4 vs. 12.5 lb feed/lb gain). These experiments demonstrate that ammoniation improved the nutritive value of diverse tropical grass hays for cattle by increasing hay consumption, nutrient digestion, and, subsequently, rate of gain.

Voluntary feed intake and digestibility by red deer ( Cervus elaphus) and sheep ( Ovis ovis) of pangola grass ( Digitaria decumbens) with or without a supplement of leucaena ( Leucaena leucocephala)

Four yearling male red deer ( Cervus elaphus) and four yearling male sheep were fed tropical grass ( Digitaria decumbens) hay supplemented with or without 30% dried leucaena ( Leucaena leucocephala) leaves. Voluntary feed intake (VFI), digestibility of dietary components, haematological parameters and serum thyroxine concentrations were determined. Leucaena supplementation reduced VFI of pangola grass by 8% but increased total DMI of both species by 30%. Digestibility of DM, OM and N was higher for both species when leucaena was fed but sheep digested these dietary components more efficiently than deer. Leucaena supplementation did not influence blood cell numbers or haemoglobin and thyroxine concentrations in either species. Deer had higher concentrations of red blood cells and lower concentrations of white blood cells than sheep. It was concluded that leucaena at 30% could be a suitable supplement for deer and sheep consuming sub-tropical pastures.

Ammoniation or Cane Molasses Supplementation of Tropical Grass Hay

Molasses-urea mixtures are often fed with low-quality hay or stockpiled grass pasture to wintering beef cattle (Bos spp.). Chemical treatment of low-quality forage may improve fiber digestibility and animal performance more than energy supplementation of the untreated forage. Laboratory, digestion, and growth studies evaluated the effects of anhydrous ammonia treatment or molasses supplementation on the feeding value of mature stargrass (Cynodon nlemfuënsis Vanderyst) hay. Ammoniation reduced (P < 0.003) neutral detergent fiber (NDF) concentration (89.5 vs. 83.3%) and increased (P < 0.01) in vitro organic matter (OM) digestion (38.6 vs. 51.2%) of the hay. Molasses supplementation (25% of the dietary dry matter) of untreated hay increased (P < 0.05) in vivo OM digestibility by cattle (51.1 vs. 56.8%), but NDF digestibility of untreated hay was reduced (P < 0.05) by molasses supplementation (59.6 vs. 54.6%). Ammoniation increased (P < 0.05) OM (61.6%) and NDF (73.2%) digestibilities compared to untreated hay fed alone or supplemented with molasses. Gestating Brahman crossbred (Bos spp.) first-calf heifers (800 lb) were placed on bahiagrass (Paspalum notatum Fluegge) pasture during the winter and fed (i) untreated hay plus a 16% crude protein molasses-urea supplement, or (ii) ammoniated hay alone. First-calf heifers fed ammoniated hay consumed more (P < 0.05) hay (18.5 vs. 23.5 lb), lost less (P < 0.05) weight during lactation and weaned heavier calves (P < 0.05) than those fed untreated hay plus molasses-urea. Milk production measured from approximately 60 to 150 d postpartum from first-calf heifers fed ammoniated hay remained constant (P > 0.10; 11.4 lb/d), while milk production from first-calf heifers fed untreated hay plus molasses-urea declined (P < 0.05; 14.0 to 5.2 lb/d) during lactation. No toxic effects of ammoniated hay were observed in first-calf heifers or their calves. Ammoniation improves the feeding value of stargrass hay, and offers an option to traditional winter feeding programs of untreated forage plus molasses-urea.

Maturity and Ammoniation Effects on the Feeding Value of Tropical Grass Hay

Maturity and Ammoniation Effects on the Feeding Value of Tropical Grass Hay

Uso da cinza insolúvel em ácido para determinar o consumo de forragem dos bovinos

Six young crossbred bulls were used to determine dry matter intake by cattle fed a tropical grass hay (Cynodon dactylon, Coastcross 1). Digestion trial lasted for 23 days being the last 7 days for feed and feces sample collections. Dry matter intake was calculated by use of adequate formulas and indicator method. Dry matter intake was calculated by acid insoluble ash HCl 2N and concentrated HCl and also by direct consumption. There was no statistical difference among methods for dry matter consumption.

Uso da cinza insolúvel em ácido como indicador natural para determinação da digestabilidade em bovinos

Six crossbred young bulls were used in a digestibility trial during 23 days being the last 7 days for feed and feces sample collections. Cynodon dactylon grass hay was the sole ration. Nutrient digestibility coefficients were calculated by total collection method and by HCl 2N and concentrated HCl, acid insoluble ash methods which were statistically different among them for dry matter, crude protein, crude fiber, crude energy and nitrogen-free extract when calculated by SCHNEIDER &amp; FLATT (1975) or LUCAS (1952) formulas. By use of total feces collection, digestibility coefficients were not statistically different. These results show the validity of acid insoluble ash methods to determine digestibility of nutrients for tropical grass hay.

The effects of sulphur supplementation on cellulose digestion in vitro and on nutrient digestion, nitrogen metabolism and rumen characteristics of lambs fed on good quality fescue and tropical star grass hays

Experiments were conducted in vitro and in vivo to determine the effects of sulphur (S) supplementation of a good quality fescue hay containing 0.27% total S and a tropical star grass hay containing 0.20% total S. Addition of S was on an isosulphurous basis of either sodium sulphate or D,L-methionine. Cellulose digestion in vitro was improved ( P < 0.001) by the addition of 1% urea. Supplementation of forage with 0.05, 0.10 or 0.15% S from either sodium sulphate or methionine also stimulated cellulose digestion in vitro. There were no differences between S sources. The addition of 0.4 or 0.8% nitrate-nitrogen (nitrate-N) (potassium nitrate) depressed ( P < 0.05) cellulose digestion in vitro of both hays. No effect of animal adaptation to nitrate was evident. Addition of S partially counteracted the depression in cellulose digestion due to nitrate. Trials were conducted in vivo in which 12 crossbred wether lambs (fescue experiment) or 12 crossbred intact male lambs (star grass experiment) were randomly assigned to one of three treatments: control (forage with no addition of S); forage plus 0.15% S as sodium sulphate; and forage plus 0.15% S as D,L-methionine. Lambs were housed in metabolism crates and each experiment was replicated twice. Dry matter intakes were highest for methionine-supplemented fescue and for S-supplemented star grass, regardless of S source. Dry matter digestibility tended to increase with S addition (fescue experiment) and was significantly higher for S-supplemented star grass. There was a significant increase ( P < 0.05) in neutral detergent fibre (NDF) and acid detergent fibre (ADF) digestibility due to supplemental S, regardless of S source. Nitrogen retention, ammonia-N and ruminal volatile fatty acids were unaffected by S supplementation.

Fiber Digestibility by Goats and Sheep

Browse appears to be important in the diet of goats, but no good explanations or reasons are in the literature. Digestibility data on browse in goats are few. Semiarid natural tropical grass hay was consumed more by goats than sheep, but digestibility coeffecients were similar between species except for crude fiber, which was digested better in goats. Rice straw was consumed more by goats than sheep, and they digested it better than sheep. When rice straw was treated with alkali, its nutritive qualities improved and digestion between goats and sheep was similar. Goats appear to be better utilizers of poor roughages.

Differences between cattle and sheep in their digestion and relative intake of a mature tropical grass hay

The dry-matter digestibility (DMD) of a low quality tropical grass hay was much higher in cattle (49.6%) than in sheep (34.6%). This difference was not due to a difference in relative intake per kg liveweight (W 0.9) nor to a difference in the diet selected. However, neutral-detergent fibre (NDF) was digested better by cattle than by sheep. For each kg of dry matter consumed, cattle digested 415 g NDF and sheep 279 g NDF. This was because 60% more of the hemicellulose and 35% more of the cellulose were digested by cattle than by sheep. Differences between cattle and sheep in the concentrations of urea and sulphate in blood, and the relatively lower excretion of N, P and Ca by the cattle suggested that the rumen micro-organisms of the cattle were utilizing these nutrients better than those of the sheep. This could have increased microbial activity in the rumen and, hence, digestion of fibre.

Intake, Digestibility and Nitrogen Utilization of Tropical Natural Grass Hay by Goats and Sheep

Intake, Digestibility and Nitrogen Utilization of Tropical Natural Grass Hay by Goats and Sheep