Ruminal Ammonia Nitrogen Concentration Research Articles

Influence of urea–calcium mixtures as rumen slow-release feed on in vitro fermentation using a gas production technique

In this experiment the effects of different urea products (urea [U] and urea–calcium mixtures [UCM]) on rumen fermentation were investigated in dependence of different energy sources by using in vitro techniques. The 7 × 2 factorial arrangement followed a completely randomised design using seven urea products (U100, U40CaCl2, U50CaCl2, U60CaCl2, U40CaSO4, U50CaSO4 and U60CaSO4) in combination with cassava chips (CC) or corn meal (CM). Compared with other treatments, the cumulative gas production (96 h) was significantly increased for U60CaCl2 + CC and U60CaSO4 + CC (p < 0.01), which was combined with a higher in vitro true digestibility (p < 0.01). In addition, the concentration of volatile fatty acids in the fluid of U60CaCl2 + CC and U60CaSO4 + CC was significantly higher than in other treatments. Urea treatments (U100 + CC and U100 + CM) caused the highest concentration of ruminal ammonia nitrogen (p < 0.01), which was significantly decreased by all UCM products in combination with CC, but not with CM. The highest levels of total bacteria, Fibrobacter succinogenes and anaerobic fungi were found for treatment U60CaCl2 + CC and U60CaSO4 + CC (p < 0.05). The findings revealed that the utilisation of U60CaCl2 and U60CaSO4 in combination with cassava chips improved the ruminal fluid fermentation in terms of NH3-N and volatile fatty acid concentration, digestibility of energy and increased the fibrobacter concentrations.

The effects of urea-treated potato pulp (PP) ensiled with beet pulp or wheat bran pellets to reduce moisture of PP and flake density of corn grain supplemented with the PP silage on digestibility and ruminal fermentation in beef steers

The effects of adding beet pulp or wheat bran to urea-treated potato pulp (PP) in order to reduce moisture of PP silage and flake density of corn grain on digestibility and ruminal fermentation in beef steers were studied in a split-plot design experiment. The whole-plot treatments were PP silage mixed with 0% added pellets (CON), 9% (as-fed basis) beet pulp pellets (BP) or 9% (as-fed basis) wheat bran pellets (WB) as water-absorbing materials. The subplot treatments consisted of supplements formulated to contain either high-density corn (HDC) or low-density corn (LDC). BP steers consumed more (BP vs WB, P = 0.011) concentrate than did WB steers, whereas hay intake did not differ between the treatments. Dry matter (BP vs WB, P = 0.023) and organic matter (BP vs WB, P = 0.029) digestibility were higher for BP steers than for WB steers. Starch digestibility was higher (P = 0.006) for LDC than for HDC. There were no differences in the concentration of ruminal ammonia nitrogen among the treatments. Molar proportions of ruminal acetate were higher for BP steers than for WB steers (BP vs WB, P = 0.030). Conversely, molar proportions of propionate were lower for BP steers than for WB steers (BP vs WB, P = 0.044). Flake density of corn did not affect ruminal characteristics. In conclusion, from the viewpoint of feed intake and digestibility, BP is superior to WB as a moisture control material for urea-treated PP silage, and flake density of corn supplemented with urea-treated PP silage does not alter ruminal fermentation.

EFFECT OF DIFFERENT FAT SOURCES ON THE PERFORMANCE AND CARCASS TRAITS OF GROWING LAMBS

Eighteen Rahmani lambs (initial body weight 30±1.3 kg and 5-6 months old) were used to determine the effect of different dietary fat sources on the performance, digestion coefficient of nutrients, ruminal parameters and carcass traits in a three months experiment. The animals were allotted into three groups, 6 animals per each. The animals of the first group were fed the control diet (without fat supplementation), while the animals of the second and third groups were fed diets containing 4% dried fat and 4% tallow, respectively. All experimental diets were formulated to provide the recommended levels of digestible energy (3.0 Mcal/kg diet) and crude protein (14.71 %) according to NRC publication (1985) for sheep. There were a significant (P<0.05) differences in the average daily gain, daily feed intake (g/head/day), and feed conversion between the different experimental groups. Lambs fed ration contained 4% dried fat recorded the highest value in daily gain and the best feed conversion. The digestion coefficients of dry matter, crude protein, crude fibre and ether extract as well as the nutritive value (DCP and TDN) were significantly (P<0.05) higher for ration containing 4% dried fat followed by ration containing 4% tallow compared to the control one.Ruminal pH values were significantly higher (P<0.05) in lambs fed diet with 4% dried fat. Ruminal ammonia nitrogen and total volatile fatty acids concentrations were significantly (P<0.05) decreased with supplementation of fat compared to the control one.Dressing percentages were increased significantly (P<0.05) by feeding supplemental fat compared to the control group. It could be concluded that, lambs fed diet with 4% dried fat recorded the best performance and the highest digestibility and carcass traits.

Nutritional Aspects of Recycling Plants By-Products and Crop Residues (Corn Stalk) in Sheep

An experiment was conducted to study the effect of long term feeding of sheep with ureated corn stalk with or without addition of molasses on feed intake, ration digestibility (dry matter, crude protein, ether extract, Ash, crude fiber, neutral detergent fiber and acid detergent fiber) and ruminal parameters which including PH, ruminal TVFAS and ammonia-nitrogen concentration. The effect of these treatments also on some blood metabolites as (glucose, total protein, total cholesterol, triglycerides, HLD-cholesterol, LDL- cholesterol, VLDL-cholesterol, total protein, albumin, globulin and BUN (Blood urea Nitrogen). The methods of preparation and storage of corn by-products (green corn and corn stalk) when fed as silage which enriched by urea also by yeast with addition of molasses on the same parameters. One year old six healthy Baladi rams, were used in this work (initial average body weight of 30 kg). They were divided into 3 similar groups (2 rams per each group). Crude protein content of treated corn stalk by 4%urea and /or 5% molasses was increased 75.4% and 113.2% respectively due to increase nitrogen content. Feed intake, EE, Ash, crude fiber, ADF and NDF were also significantly decreased. Total digestible nutrients and Digestion Coefficient of DM, OM, EE , NFE and CP did not show any significant difference. Digestion Coefficient of crude fiber fractions (CF, ADF and NDF) were significantly increased. The ruminal Total VFA values were significantly decreased whereas the ruminal Ammonia nitrogen concentration was significantly increased. Moreover, blood glucose, total protein, albumin, globulin and BUN were increased but total lipids, total cholesterol and triglycerides were decreased in treated groups compared with the control.

Effect of Humic/Fulvic Acid in Beef Cattle Finishing Diets on Animal Performance, Ruminal Ammonia and Serum Urea Nitrogen Concentration

McMurphy, C.P., Duff, G.C., Harris, M.A., Sanders, S.R., Chirase, N.K., Bailey, C.R. and Ibrahim, R.M. 2009. Effect of humic/fulvic acid in beef cattle finishing diets on animal performance, ruminal ammonia and serum urea nitrogen concentration. J. Appl. Anim. Res., 35: 97–100. This study was designed to investigate the effects of a humate supplement on rumen ammonia N (RAN), serum urea N (SUN) and live performance in beef cattle finishing diets. Twenty-four English cross steers (BW 432±5 kg) were stratified by weight, randomly assigned to individual pens and fed one of the four diets, containing 0 (control), 0.5, 1.0 or 1.5% humic/fulvic acid, for 56 d. Control diets contained 33.3 mg/kg monensin. Steers were weighed at d 0, 28 and 56. Blood (jugular veni-puncture) samples and rumen (esophageal tube) samples were taken prior to feeding on d 0 and there after prior to and 4 h post feeding on d 28 and 56. Rumen fluid pH was determined immediately, acidified with HCl and stored (-20C) for subsequent RAN analysis. Serum was also stored (-20C) for analysis of SUN. During the 56 d period there was no difference in DMI (P>0.58), ADG (P>0.24) or G:F (P>0.28) between treatments. There were no two or three way interactions for SUN (P>0.95), RAN (P>0.87) or rumen pH (P>0.15). There was a tendency for a cubic response (P<0.10) for RAN and SUN, however, no biological significance could be determined. These results suggest that humic/fulvic acid does not affect DMI, ADG, G:F, SUN, RAN and pH in finishing steers when compared to those fed monensin.

Rumen fermentation pattern of dairy heifers fed restricted amounts of low, medium, and high concentrate diets without and with yeast culture

Restricted feeding and high concentrate diets are potential strategies for growing dairy heifers. Ruminal manipulation with additives such as Saccharomyces cerevisiae yeast culture (YC) has been shown to alter digestibility when added to this type of diet. An experiment was conducted to investigate the ruminal fermentation and in situ digestibility of diets with 3 different levels of forage to concentrate (F:C) fed at restricted intake without and with YC addition. Three cannulated post-pubertal Holstein heifers (age 18.0 ± 1.2 months; body weight 449.6 ± 19.7 kg) were fed diets consisting of corn silage as the sole forage source in a 3 period (35-day) Latin square design. Heifers were fed diets for 21 days with no YC addition, followed by 14 days where YC was added to the diet (1 g/kg as fed basis). Low (LC), medium (MC), and high (HC) concentrate diets (20, 40, and 60% concentrate) were fed once daily on a restricted basis to provide 0.22 Mcal ME/kg empty BW 0.75. Rumen fluid was sampled on days 18 and 32 of each period, and rumen contents were evacuated on days 21 and 35 of each period. An in situ study was done on days 14 to 17 and on days 28 to 31. Mean ruminal pH was not different between dietary treatments and no YC effect was detected. Mean total volatile fatty acids (VFA) and ruminal ammonia-nitrogen (NH 3-N) concentration was also not different among diets with different F:C. Molar proportions of acetate were decreased, and propionate were increased; while the acetate-to-propionate ratio was decreased as the concentrate level increased from LC to HC. Total VFA, propionate, and acetate as well as isoacids concentration increased, yet NH 3-N concentration decreased with YC addition in all diets. From these results we conclude that feeding HC diets in restricted amounts had minimal effects on rumen fermentation rate between different F:C diets. The addition of YC modified NH 3-N and volatile fatty acid concentrations in the rumen in all 3 diets in this study, presumably through alterations in end-product production and utilization.

Nutritional properties of potato protein concentrate compared with soybean meal as the main protein source in feed for the double-muscled Belgian Blue bull

The objective of this experiment was to compare the nutritional properties of potato protein concentrate, a by-product of the starch industry produced entirely in Europe, with that of soybean meal (SBM), for growing cattle. The experiment was conducted on double-muscled Belgian Blue bulls, fitted with rumen, duodenal and ileal cannulas, according to a 4 × 4 Latin square design. They were fed three different iso-N and iso-net energy diets formulated according to the Dutch feed evaluation system, differing in the nature of the main protein source, which was either SBM (‘SBM’ treatment), potato protein concentrate (PPC, ‘PPC’ treatment) or an iso-N mixture of these two protein sources (‘mixed’ treatment). A fourth treatment consisted of ‘PPC’ supplemented by 9.5% digestible proteins supplied by duodenal perfusion of sodium caseinate (CAS, ‘PPC + CAS’ treatment). No significant difference was observed in the ruminal fluid pH, whereas both ‘PPC’ and ‘PPC + CAS’ had the effect of reducing the ruminal ammonia nitrogen (N-NH3) concentration. No significant difference was observed in the apparent intestinal digestibility of the dry matter (DM), organic matter (OM) or N. Outflows of non-NH3-N, microbial proteins and dietary proteins from the rumen were similar for ‘PPC’, ‘SBM’ and ‘mixed’, and increased with CAS infusion by 20%, 17% and 27%, respectively. On the basis of in vivo observations, the degradability of SBM and PPC proteins was estimated at 0.60 and 0.43, respectively, corresponding to the values quoted in the literature. The supply of digestible essential amino acids (EAA) was significantly greater with ‘PPC + CAS’ and did not differ among ‘SBM’, ‘mixed’ and ‘PPC’. This illustrates the difficulty of altering the amino acid (AA) pattern of digestible protein by the nature of the protein of dietary origin when an animal is fed a high nutritional value diet. N retention was not affected by replacing SBM with PPC, but increased by 10% with CAS infusion. On the basis of the plasma AA pattern, the supply of digestible Met was probably limiting with ‘SBM’, ‘mixed’ and ‘PPC’. The CAS perfusion supplemented all AA, including Met, leading to increased N retention. This improvement was limited, however, and N utilisation remained unchanged between treatments. In conclusion, despite a more favourable EAA pattern, PPC offered no advantage compared with SBM for growing bulls when diets were formulated according to the Dutch feed evaluation system.

Avaliação da monensina administrada pela forma convencional ou por dispositivo de liberação lenta (bólus) em bovinos alimentados com forragens de baixo valor nutritivo e suplementados ou não com uréia

Foi objetivo desta pesquisa avaliar os efeitos da monensina sódica administrada pela forma convencional ou por dispositivo de liberação lenta sobre o perfil fermentativo ruminal de bovinos alimentados com volumosos de baixo valor nutritivo e suplementados ou não com nitrogênio não-protéico. Doze fêmeas bovinas (736 kg de PV) fistuladas no rúmen foram distribuídas em blocos em função do peso vivo, utilizando-se dois períodos sucessivos de 28 dias cada (24 unidades experimentais). O arranjo de tratamentos - combinados com a presença ou ausência de suplementação diária de 20 g uréia/100 kg PV - correspondeu ao fatorial 3 x 2, no qual duas formas de administração de monensina (convencional ou dispositivo de liberação lenta), na dose de 300 mg/anim.dia, foram comparadas ao controle. O feno de Tifton 85 de baixo valor nutritivo foi o único alimento oferecido. Amostras de líquido ruminal foram coletadas no 28º dia às 0, 2, 4, 6 e 8 horas após a primeira refeição e o feno, incubado por 0, 6, 12, 24, 48, 72 e 96 horas, entre o 24º e 27º dia, para avaliação da degradabilidade in situ. O único efeito causado pela administração da uréia foi o aumento das concentrações ruminais de nitrogênio amoniacal. Independentemente da suplementação com uréia, os tratamentos convencional e com bólus diminuíram o consumo de MS em 25,4 e 27,8%, respectivamente, e a degradabilidade efetiva da FDN do feno em 17,4 a 34,4% e 11,9 a 12,7%, dependendo da taxa de passagem ruminal utilizada, e aumentaram a concentração molar de ácido propiônico em 60,2 e 42,7%, quando comparados ao controle. Entretanto, não alteraram o pH, a concentração total de AGVs ou de amônia. Com base na relação acetato/propionato ruminal, o tratamento com bólus apresentou eficiência de 77%, em relação ao tratamento convencional, o que corresponde a uma liberação de 232 mg de monensina sódica/anim.dia.

Estimation of Ruminal Degradation and Intestinal Digestion of Tropical Protein Resources Using the Nylon Bag Technique and the Three-step In vitro Procedure in Dairy Cattle on Rice Straw Diets

The experiment was carried out using fistulated multiparous Holstein Friesian crossbred (75% Holstein Friesian and 25% Red Sindhi) dairy cows in their dry period fed on untreated rice straw to evaluate the nutritive value of local protein feed resources using the in sacco method and in vitro pepsin-pancreatin digestion. Experimental feeds were cottonseed meal (CSM); soybean meal (SBM); dried brewery's grains (DBG); palm kernel meal (PSM); cassava hay (CH); leucaena leaf meal (LLM). Each feedstuff was weighed into duplicate nylon bags and incubated in each of the two rumen fistulated cows for 0, 2, 4, 8, 16, 24, and 48 h. Rumen feed residues from bags of 16 h incubation were used for estimation of lower gut digestibility by the technique of in vitro pepsin-pancreatin digestion. Ruminal ammonia-nitrogen (NH3-N) concentrations did not differ between treatments or time with a mean of 5.5 mg%. Effective degradability of DM of CSM, SBM, DBG, PSM, CH and LLM were 41.9, 56.1, 30.8, 47.0, 41.1 and 47.5%, respectively. Effective degradabilities of the CP in feedstuffs were 49.6, 59.2, 40.9, 33.5, 47.3 and 65.0% for the respective feedstuffs. The CP in vitro pepsin-pancreatin digestibility as ranked from the highest to the lowest were SBM, CSM, LLM, CH, DBG, PSM, respectively. The intestinal and total tract digestion of feedstuffs in the current study were relatively lower than that obtained from previous literature. The results of this study indicate that SBM and LLM were highly degradable in the rumen, while CH, CSM and DBG were less degradable and, hence resulted in higher rumen undegradable protein. Soybean meal and LLM could be used to improve rumen ecology whilst CH, CSM and DBG could be used as rumen by-pass protein for ruminant feeding in the tropics. (Key Words : Rumen Degradability, Rumen By-pass Protein, In sacco, Three-step Technique, Protein Sources, Digestibility, Rice Straw, Cassava Hay)

Ruminal peptide and ammonia nitrogen concentrations in steers fed diets with different concentrate to lucerne hay ratios

In ruminants, as much as 50% of the dietary crude protein can be converted to ammonia by ruminal microorganisms. A part of ammonia can be utilized as a bacterial nitrogen source; however, rates of ammonia production often exceed rates of ammonia utilization. Peptides are intermediates in the conversion of ingested protein to ammonia in the rumen and their accumulation depends upon the nature of diet (Mesgaran &amp; Parker, 1995). The objective of the present experiment was to investigate the effect of diets differing in concentrate: lucerne hay ratios on the ruminal pH, ammonia-nitrogen concentration and ruminal peptide nitrogen concentration in Holstein steers.

Effects of Addition of Essential Oils and Monensin Premix on Digestion, Ruminal Fermentation, Milk Production, and Milk Composition in Dairy Cows

Four ruminally cannulated, lactating Holstein cows were used in a 4×4 Latin square design (28-d periods) with a 2×2 factorial arrangement of treatments to study the effects of dietary addition of essential oils (0 vs. 2g/d; EO) and monensin (0 vs. 350mg/d; MO) on digestion, ruminal fermentation characteristics, milk production, and milk composition. Intake of dry matter averaged 22.7kg/d and was not significantly affected by dietary additives. Apparent digestibilities of dry matter, organic matter, neutral detergent fiber, and starch were similar among treatments. Apparent digestibility of acid detergent fiber was increased when diets were supplemented with EO (48.9 vs. 46.0%). Apparent digestibility of crude protein was higher for cows fed MO compared with those fed no MO (65.0 vs. 63.6%). Nitrogen retention was not changed by additive treatments and averaged 27.1g/d across treatments. Ruminal pH was increased with the addition of EO (6.50 vs. 6.39). Ruminal ammonia nitrogen (NH3-N) concentration was lower with MO-supplemented diets compared with diets without MO (12.7 vs. 14.3mg/100mL). No effect of EO and MO was observed on total volatile fatty acid concentrations and molar proportions of individual volatile fatty acids. Protozoa counts were not affected by EO and MO addition. Production of milk and 4% fat-corrected milk was similar among treatments (33.6 and 33.4kg/d, respectively). Milk fat content was lower for cows fed MO than for cows fed diets without MO (3.8 vs. 4.1%). The reduced milk fat concentration in cows fed MO was associated with a higher level of trans-10 18:1, a potent inhibitor of milk fat synthesis. Milk urea nitrogen concentration was increased by MO supplementation, but this effect was not apparent when MO was fed in combination with EO (interaction EO×MO). Results from this study suggest that feeding EO (2g/d) and MO (350mg/d) to lactating dairy cows had limited effects on digestion, ruminal fermentation characteristics, milk production, and milk composition.

Effect of Cassoy-urea Pellet as a Protein Source in Concentrate on Ruminal Fementation and Digestibility in Cattle

Four male crossbred native beef cattle (average body weight of 427.7 kg) were randomly allocated to four types of cassoy-urea pellet as a source of protein in concentrate according to a 4x4 Latin square design to determine effect of diets on ruminal fermentation and nutrient digestibility. The four types of cassoy-urea pellets contained cassava hay, soybean meal, urea and binding agent at 79.2:19.8:0:1 (27.9% CP dry matter), 78.4:19.6:1:1 (30.4% CP), 77.6:19.4:2:1 (33.0% CP) and 99:0:0:1 (23.8% CP) for dietary treatments; 1, 2, 3 and 4, respectively. All four concentrate mixtures contained similar crude protein levels (11% CP) and were fed to animals in two equal parts (0.5% of body weight per day) while urea-treated rice straw (5% urea) was given ad libitum. The experiment revealed that dietary concentrate treatments had no effect on dry matter intake while digestibilities of neutral-detergent fiber and crude protein were higher (p<0.05) in cattle fed dietary treatments 1, 2 and 3 than in cattle fed dietary treatment 4. Ruminal ammonia-nitrogen (NH 3 -N), was higher and acetic acid concentration (C2) and ratio of C2 to propionic acid (C3) were lower (p<0.05) in cattle fed dietary treatments 1, 2 and 3 than in those on treatment 4. It is concluded that use of cassoy-urea pellet as a protein source in concentrates for cattle resulted in improvement of digestibility, ruminal fermentation and rumen ecology. Further research using cassoy-urea pellet in feeding trials with milking cows and fattening beef should be undertaken.

The effect of natural zeolite on nutrient digestibility, carcass traits and performance of Holstein steers given a diet containing urea

AbstractThe objective of this study was to evaluate effects of natural zeolite (clinoptilolite) on nutrient digestibility, carcass attributes and performance of Holstein steers given a diet containing urea. Forty-five Holstein steers (309 (s.d. 11·2) kg) were given diets as follows: control diet based on maize and soya-bean meal (SBM); treatment 2 (T2), control diet (without SBM) containing 20 g/kg urea; treatment 3 (T3), control diet (without SBM) containing 20 g/kg urea and 30 g/kg zeolite. Just before feeding, ruminal ammonia levels were low in all treatments. At 2·5 h post feeding, steers given T2 and T3 diets had higher (P&lt;0·05) ruminal ammonia concentration than the control. At 5·5 h post feeding, steers on T3 diet had the highest ruminal ammonia concentration, which was higher (P&lt;0·05) than the value for steers given T2 diet. Plasma urea nitrogen level increased post feeding for all treatments. At 3 h post feeding, the level for steers given T2 diet was higher (P&lt;0·05) than those on control and T3 diets but at 6 h post feeding, the level was higher for steers on T3 diet. No differences (P&gt;0·05) were observed in dry-matter intake among treatments. Live-weight gain and gain: food ratio were highest (P&lt;0·05) for steers on the control diet, with no differences (P&gt;0·05) between steers given T2 and T3 diets. Including zeolite in a diet containing urea had no effect (P&gt;0·05) on total tract digestibility coefficients of dry matter, organic matter and crude protein but increased (P&lt;0·05) digestibility of neutral-detergent fibre and acid-detergent fibre. Hot carcass weight and kidney, pelvic and heart fat weight of steers were highest in control, intermediate in T3 and least in T2 (P&lt;0·05). No differences (P&gt;0·05) were found in longissimus muscle area and fat thickness over longissimus muscle among treatments. Including 30 g/kg of zeolite in a diet containing 20 g/kg of urea decreased ruminal ammonia nitrogen concentration, plasma urea nitrogen level and increased fibre digestibility but its effect on feedlot performance was negligible.

Níveis de proteína bruta em dietas para bovinos de corte: parâmetros ruminais, balanço de compostos nitrogenados e produção de proteína microbiana

RESUMO Avaliaram-se o pH e a concentração de amônia ruminal (N-amoniacal), a taxa de passagem, o balanço de compostos nitrogenados e a produção de proteína microbiana em novilhos Holandês x Zebu alimentados com dietas contendo quatro níveis de proteína bruta (10,5; 12; 13,5 e 15%), com base na matéria seca. As dietas foram constituídas de 65% de feno de capim-tifton 85 e 35% de concentrado. Foram utilizados quatro bovinos castrados fistulados no rúmen e abomaso, com peso vivo médio inicial de 487,3 kg, distribuídos em um quadrado latino 4 x 4. Cada período experimental teve duração de 20 dias: dez para adaptação às dietas e dez para coletas. O pH e N-amoniacal foram mensurados no fluido ruminal imediatamente antes e 2, 4, 6 e 8 horas, após o fornecimento da dieta. A taxa de passagem foi determinada pelo modelo unicompartimental, utilizando-se óxido de cromo como indicador. Para determinação da produção de proteína microbiana, utilizaram-se as bases purinas (RNA) no abomaso como indicador microbiano. A concentração de amônia e o pH ruminal foram influenciados pelos tempos de coleta, estimando-se valores máximos de 17,43 e 6,54 mg/dL, às 3,62 e 4,17 horas após a alimentação, respectivamente. A taxa de passagem da digesta não foi afetada pelas dietas, registrando-se valor médio de 3,69%/h. Os fluxos de compostos nitrogenados no abomaso e a eficiência de síntese microbiana também não foram afetados pelos níveis de proteína bruta das dietas, ao passo que o balanço de nitrogênio, expresso em g/dia, aumentou linearmente com o incremento de proteína bruta.

Lactational Response of Cows Fed Condensed Corn Distillers Solubles

Fifteen Holstein cows (6 multiparous and 9 primiparous) in early lactation were used in a replicated 3×3 Latin square design with 5-wk periods to evaluate the use of condensed corn distillers solubles (CCDS) in the total mixed ration. Diets were control (0%), low (5%), or high (10% of dry matter) CCDS. All diets contained alfalfa hay, corn silage, rolled corn, and a concentrate supplement formulated to yield isonitrogenous diets. Condensed corn distillers solubles replaced a portion of the rolled corn and soybean meal in the control diet. Data were collected from wk 3 to 5 of each 5-wk period. Dry matter intakes (23.4, 24.4, and 22.5 kg/d for control, low, and high CCDS, respectively) were similar for CCDS and control and tended to be greater for low than for high CCDS. Milk yields (34.1, 35.5, and 35.8 kg/d) were greater for added CCDS vs. control, with no additional benefit found by feeding a high over a low amount of CCDS. Milk fat percentage decreased slightly, whereas protein and lactose production increased when cows were fed CCDS. Medium-chain fatty acids in milk fat were decreased and long-chain fatty acids increased by feeding CCDS, and similar changes were found comparing high with low level of CCDS. Unsaturated fatty acids in milk fat tended to be higher for diets containing CCDS compared with control and were higher for high compared with low inclusion. Ruminal ammonia and serum urea nitrogen concentrations were lower when cows were fed CCDS. This study indicated that it is advantageous to feed CCDS at 5% of dry matter; however, some beneficial changes in milk fatty acid composition were achieved by doubling that amount.

Níveis de proteína em suplementos para terminação de bovinos em pastejo durante o período de transição Seca/Águas: digestibilidade aparente e parâmetros do metabolismo ruminal e dos compostos nitrogenados

Avaliaram-se aspectos das digestibilidades aparente total e parcial e parâmetros do metabolismo ruminal e dos compostos nitrogenados em novilhos mestiços suplementados durante a fase de transição entre os períodos seco e chuvoso. Foram utilizados cinco novilhos mestiços holandês x zebu com idade e peso médios iniciais de 24 meses e 304 kg, manejados em cinco piquetes de B. decumbens (0,34 ha). Foram fornecidos suplementos (4 kg/animal/dia) constituídos por fubá de milho, grão de soja integral, uréia, sulfato de amônia e mistura mineral, sendo formulados para apresentarem níveis de 12; 16; 20 e 24% de proteína bruta (PB), com base na matéria natural. O experimento foi conduzido em quatro períodos experimentais de 21 dias, sendo analisado por delineamento em quadrado latino 4x4. O quinto animal foi mantido sem suplementação e utilizado como medida de comparação descritiva (SAL). Não foram observados efeitos da composição dos suplementos sobre a digestibilidade total e parcial da matéria seca, matéria orgânica (MO) e fibra em detergente neutro e sobre os fluxos abomasais de nitrogênio (N) total, amoniacal e microbiano (NMIC). Os níveis de N amoniacal ruminal foram incrementados linearmente pela elevação dos níveis de PB dos suplementos. A eficiência de síntese microbiana apresentou valor médio de 17,5 g NMIC/kg MO fermentada no rúmen (MOFR) para os suplementos, sendo superior a SAL (10,6 g NMIC/kg MOFR). A elevação dos níveis

Effect of propylene glycol and undegradable protein source on rumen fermentation, blood metabolism and milk production in lactating dairy cows

Eight lactating Holstein cows were divided into two groups (n = 4) and used in a double reversal trial with three periods of 14 days each, to evaluate diets containing propylene glycol (PG) and ruminally undegradable protein (RUP) blend on milk yield and composition, ruminal fermentation and blood metabolism. The control diet contained 20% chopped Sudangrass hay, 20% cubed alfalfa hay, 12% corn silage, and 48% of the respective concentrate mixtures (dry matter basis). The experimental diet (PG + RUP) partially replaced the concentrate mixture from the control diet with 1.4% PG and 2.1% RUP. Both diets contained about 16% crude protein and 71% total digestible nutrients. Dry matter intake was similar between the two diets. Daily production of milk, milk lactose and milk solids-not-fat increased by 9.0%, 11.3% and 9.3%, respectively (P < 0.1), for cows fed diets with PG + RUP; milk composition was unchanged. Although the concentration of ruminal total volatile fatty acids was unchanged, the proportion of propionic acid increased, and the proportion of acetic acid decreased with PG + RUP. The concentration of ruminal ammonia nitrogen and number of ciliate protozoa was not significantly affected by PG + RUP. The concentration of glucose in blood plasma increased, the concentration of urea nitrogen was unaffected, and the concentration of some essential free amino acids decreased with PG + RUP. It is suggested that these changes might be caused predominantly by PG, and the addition of PG may exert a favorable effect on milk production through increased metabolism.

Effects of barley silage of different theoretical cut length on digestion kinetics in ruminants

Two studies were conducted to determine the effects of two theoretical lengths of cut (TLC) (short = 4.7 mm and long = 18.8 mm) on the feeding value of barley silage to steers fed an all-forage diet. In the first study, six steers were used to determine intake of dry matter, total tract digestibility of dry matter (DMD), neutral detergent fiber (NDFD), and acid detergent fiber (ADFD) in a replicated switchback design. In the second study, six steers equipped with rumen cannulas were used to determine the effects of barley silage particle size on ruminal kinetic and fermentation parameters. Feeding short barley silage to steers increased (P &lt; 0.05) dry matter intake (DMI), DMD, NDFD, and ADFD compared with feeding long barley silage. The results of the second study showed that reducing barley silage particle size decreased (P &lt; 0.05) ruminal retention time and increased (P &lt; 0.05) passage rate of particulate matter. Ruminal pH was lower (P &lt; 0.05) at 1000, 1200, 1800, 2000, and 2200 h for steers fed the short barley silage compared with those fed the long barley silage. However, the effects of barley silage particle size on ruminal ammonia nitrogen and volatile fatty acid (VFA) concentrations were minimal. Eating rate was similar in both dietary treatments (average 40.3 g min-1). However, steers fed the long silage produced more (P &lt; 0.05) saliva per kg DMI compared with those fed the short barley silage diets. It was concluded that reducing TLC of barley silage increased feed intake and improved total tract utilization of cell wall components by steers. Results of the metabolism study also showed changes in fermentation parameters, but no adverse physiological changes were noted when cattle were fed all forage diets. Key words: Barley silage, particle size, fermentation patterns

Deep-Stacked Broiler Litter as a Protein Supplement for Dairy Replacement Heifers

Fifty Holstein dairy heifers, [two replications of 25 heifers; average body weight (BW) 227 kg], were assigned to one of the following treatments for 105 d. Treatments 1 through 4 are given as the percentage of supplemental crude protein (CP) from soybean meal and deep-stacked broiler litter, respectively: 1) 100 and 0%; 2) 67 and 33%; 3) 33 and 67%; 4) 0 and 100%; and 5) 67% of supplementary CP from deep-stacked broiler litter and 33% from a source of rumen undegradable protein (RUP). All rations were formulated to contain 15% CP and 68% TD Non a dry matter basis. Dry matter intake was not significantly different among treatments at 10.1, 10.2, 10.4, 9.4, and 9.1 kg/d for treatments 1 through 5, respectively. Average daily BW gains (1.35, 1.37, 1.28, 1.17, and 1.24 kg/d for treatments 1 through 5, respectively) decreased linearly as the level of litter feeding increased and was not influenced by increasing RUP in treatment 5. Feed efficiency was not affected by the level of deep-stacked broiler litter feeding. Ruminal ammonia and plasma urea nitrogen concentrations decreased linearly as the level of litter feeding increased. Feeding additional RUP decreased ruminal ammonia concentration in treatment 5 to a level similar to treatment 4. This suggests that the protein in deep-stacked broiler litter may be more undegradable than that in soybean meal and that RUP in broiler litter may be higher than previously thought. Results from this study indicate that deep-stacked broiler litter has potential as a low-cost CP source for growing dairy heifers.

The effect of different levels of inorganic sulphur on the rumen parameters of Raini goat

Added sulphur (S) in the diet of ruminants has an equivocal effect on the ruminal fermentation. For example, Hegarty et al. (1994) reported an increased total VFA concentration in the rumen of sheep fed a high S diet versus those offered a low S diet (&lt;0.25%, DM basis). Moderated high percentages of S (0.4-0.6%) in the diet of sheep have generally had no effects on ruminal VFA and ammonia-nitrogen concentrations (deOliveira et al., 1996). Working with Angora goats, Qi et al. (1992) noted that total ruminal fluid VFA concentration ranged from 76.7 to 79.1 mM and was not affected by added S (0.16-0.4%). There is limited information related to the influence of supplemental S on the metabolic responses in the rumen of Cashmere goat. Therefore, an experiment was conducted with an Iranian native breed of Cashmere producing goat, Raini, to evaluate the metabolic responses in rumen parameters to S supplementation.