Changes in cell wall composition and in vitro degradation of corn stover fractions (leaf, upper stem and lower stem) with advancing maturity and in response to NH; treatment were determined, and possible inhibitory mechanisms of lignin were evaluated. With advancing maturity, IVDMD decreased (P<.001), associated with decreases (P<.001) in CP and water soluble carbohydrates (WSC), and increases (P<.001) in NDF and ADF. The IVDMD of leaf was higher (P<.001) than of stems, associated with higher CP, hemicellulose:cellulose, and arabinan:xylan, and lower lignin methoxyl content. A hypothesis of formation of reactive quinone methide intermediates from lignin during rumen fermentation was tested in vitro by incubating corn stover fractions with S-containing reducing agents. Sulphur incorporation into residual fiber occurred (P<.05), indicative of nucleophilic addition to quinone methide intermediates. Degradation of NDF was highly correlated with lignin methoxyl content. The impact of lignin on cellulose degradation was studied using lignocellulosic hydrogels, in which hydroxypropylated or unmodified hardwood lignin was blended with cellulose. In vitro cellulose degradation of lignocellulose blends was higher (P<.01) than of control. Addition of lignin at incubation depressed (P<.01) cellulose degradation. Hydroxypropylation enhanced (P<.001) the increase in cellulose degradation with lignin blending, and reduced (P<.001) the inhibitory effect of lignin addition at incubation. Treatment of drought-stressed corn stover with 3% aqueous NH₃ decreased (P<.05) NDF, compared to isonitrogenous NH₃ addition and control, associated with solubilization of hemicellulose. Esterified phenolic acids were released (P<.05) by NH₃ treatment in upper stem. The IVDMD and NDF degradation increased (P <.001) after ammoniation, with higher (P<.05) values for NH₃ treatment than NH₃ added in leaf. The in vitro response to ammoniation of fractions of drought-stressed and non-drought stressed corn stover harvested in subsequent years was compared, using N-sufficient and N-limiting buffers. Response was highest (P<.001) for non-drought stressed stover fractions, and in N-limiting medium. Response appeared to be affected by high concentration of WSC in lower stalks of drought-stressed stover. / Ph. D.

Two studies were conducted during the grazing season of 1997. Study 1 consisted of three Experiments, and the objectives were to compare milk production and composition, body weight change and body condition score, and to determine time patterns of grazing between cows supplemented with different forms and amounts of corn. Also rumen fermentation parameters were measured in cows supplemented with two different types of corn. In study 2, milk yield was measured when grazing pasture was supplemented to lactating Holstein cows fed a typical TMR diet. Predominantly orchardgrass pastures with lesser amounts of white clover and Kentucky bluegrass were grazed during both studies. In Experiment 1, 36 Holstein cows were supplemented either with 6, 6, 6, or 4 kg/d DM of high moisture corn, coarsely ground corn, finely ground corn, or high moisture corn in two equal feedings, respectively. Milk yield was similar (30.3 kg/d) among treatments. Milk protein (2.97%) and MUN (14.7 mg/dl) did not differ among treatments. Body weight change and body condition score change were similar among treatments (23.1 kg and -0.24). During Experiment 2, four rumen-cannulated cows in mid-lactation were supplemented 6 kg/d DM of either coarsely ground corn or high moisture corn in two equal feedings. After the p.m. milking, ruminal pH was measured and rumen fluid samples were collected to determine ammonia N and VFA. While grazing, this was repeated at 0.5, 1, 2, 3,...8 h post-corn feeding (0 h). Ruminal pH was similar for both corn supplements and was lowest (5.9 and 5.8) at 5 and 8 h, respectively. Rumen ammonia N concentrations started to increase approximately 2 h after cows began grazing, reaching maximum levels 5 h later. In Experiment 3, the number of cows grazing, lying, or standing were recorded every half hour, for two consecutive days, while grazing. Cows grazed an average of 6.4 h/d, 4.1 h in the afternoon and 2.3 h in the morning. Similarity in milk production, milk composition, BW change, and BCS between treatments indicates that the quality and availability of pasture permitted equal response regardless of the type or amount of corn supplemented. Fifty four Holstein cows in mid lactation were used in Study 2. Cows were fed either a TMR diet only, or were fed TMR during half of the day (after the a.m. or p.m. milking according to the treatment) and supplemented with grazing pasture during the other half of the day. Milk production was slightly but significantly higher for cows on the TMR treatment (29.1 vs. 28.2 and 27.6). No significant difference between treatments was observed in FCM (27.7 kg/d), and milk fat (3.47) and protein percentage (3.23). While BW change did not differ among treatments (25.7 kg), body condition score increased more in cows fed only a TMR diet (0.14 vs. -0.06 and 0.01). The TMR intake was significantly different between treatments, being highest for cows on the TMR treatment and lowest for cows grazing after the p.m. milking (26.6 vs. 20.3 vs. 17.5 kg/d DM). Income over feed cost differed between treatments, and was approximately 15.3% higher for cows supplemented with high quality pasture during the afternoon compared to cows on TMR. Dairy farmers may obtain economical benefits by practicing this type of management during the grazing season with little effect on milk yield. / Master of Science

Degradation kinetics of carbohydrate fraction of commercial concentrate feeds for weaned calves, heifers, lactating and dry dairy cattle / Variations in composition and disappearance of nutrients in dairy cattle feeds are dictated by ingredients, methods of processing, storage while milk production levels depend on the animal, environmental factors and largely on pools of available carbohydrates, proteins, vitamins and minerals in the concentrate feeds. There is a wide variety of concentrates for dairy cattle on the formal and informal markets and dairy farmers need to be astute in selecting feeds appropriate for specific production periods and animals to sustain their businesses. Composition of nutrients displayed on concentrate containers is however inadequate for in-depth assessment of products. This study determined nutrient composition, rumen dry matter disappearance and microbial colonization on residual substrate on commercial concentrate feeds and simulated total mixed rations for dairy calves, heifers, lactating and dry cows based on common feeding guidelines. Equivalent feeds for each herd group were obtained from three suppliers in the formal markets in Gauteng province of South Africa, making a total of twelve. An analysis of the data on container labels for the herd groups displayed similar feed values, as also reflected on the recommendation Tables of Act 36: Feeds and Fertilizer bill 1947 of South Africa. / Agriculture, Animal Health and Human Ecology / M.Sc. (Agriculture)

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The effect of Acid Buf and combinations of Acid Buf and Sodium bicarbonate in dairy cow diets on production response and rumen parameters The objective of this study was to determine the effect of Acid Buf alone, or in combination with sodium bicarbonate, on milk production, milk composition and selected rumen parameters. A high concentrate TMR, formulated to be potentially acidotic, was used to construct four dietary treatments in which Acid Buf (AB), the skeletal remains of the seaweed Lithothamnium calcareum, was used alone or in combination with sodium bicarbonate (BC). The diets contained 3.5 g/kg of AB (Treatment 1) or 1.75 g/kg of AB and 1.75 g/kg of BC (Treatment 2) or 3.5 g/kg of AB and 3.5 g/kg of BC (Treatment 3) or 3.5 g/kg of AB and 5.2 g/kg of BC (Treatment 4). The response to treatment was determined using eight ruminally cannulated lactating Holstein cows randomly allocated to treatments according to a 4 x 4 (n=2) Latin square design, with four treatments and four periods. The total experimental period was 100 days in which every cow received each diet for a period of 18 days prior to a data collection period of 7 days. Rumen pH was monitored continuously over 2 days using a portable data logging system and in-dwelling electrodes. Samples of rumen fluid were collected for volatile fatty acid (VFA) analyses. During each data collection period, milk production was recorded twice daily for 7 days, whereas milk was sampled twice daily for five consecutive days for component analysis. Cows were fed ad libitum and dry matter intake was recorded individually. Treatment had no significant effect on milk production, milk composition or feed intake. Ruminal pH profiles of all the treatments indicated that the diets were well buffered. Average pH over 24 hours was 6.0, 6.1, 6.1 and 6.2 for Treatments 1, 2, 3 and 4, respectively. The pH did not go below 5.8 for any of the treatments and increasing levels of sodium bicarbonate increased the diurnal profile such that at the highest level (Treatment 4), the pH profile ranged from 6.1 to 6.5. Although not significant, Treatment 1 (Acid Buf alone) numerically resulted in the highest milk output without compromising milk quality. It is proposed that high rumen pH may impact negatively on milk output by increasing the acetate:propionate ratio to the detriment of rumen efficiency. Treatment had no significant effect on total VFA concentration, but there seemed to be a tendency for increased total VFA concentration as the level of sodium bicarbonate increased. The acetate:propionate ratio of Treatment 1 (2.91) was significantly lower than Treatment 4 (3.65) (P<0.05). The use of buffers which react to increasing acidity in the rumen may therefore provide an efficient, safe solution to rumen acidosis. This study confirmed previous results indicating that a daily intake of 80 g of Acid Buf by cows receiving high concentrate diets would support high milk production without compromising milk solids contents. / AFRIKAANSE OPSOMMING: Die effek van Acid Buf en kombinasies van Acid Buf en Natriumbikarbonaat in melkkoeidiëte op melkproduksie, melksamestelling en rumenparameters Die doel van die studie was om die invloed van Acid Buf alleen, of in kombinasie met natriumbikarbonaat, in melkbeesdiëte op melkproduksie en melksamestelling, asook op bepaalde rumenparameters, te bepaal. ‘n Volledige dieet met ‘n hoë kragvoerinhoud, wat geformuleer is om potensieel asidoties te wees, is gebruik om vier dieetbehandelings saam te stel waarin Acid Buf (AB), die skeletoorblyfsels van die seegras Lithothamnium calcareum, alleen of in kombinasie met natriumbikarbonaat (BK) gebruik is. Een basale diet is dus geformuleer en die behandelingsdiëte het onderskeidelik 3.5 g/kg AB (Behandeling 1) of 1.75 g/kg AB en 1.75 g/kg BK (Behandeling 2) of 3.5 g/kg AB en 3.5 g/kg BK (Behandeling 3) of 3.5 g/kg AB en 5.2 g/kg BK (Behandeling 4) bevat. Agt rumen-gekannuleerde lakterende Holsteinkoeie is ewekansig aan die behandelings toegeken in ‘n 4 x 4 (n=2) Latynse vierkantontwerp met vier behandelings en vier periodes. Die totale eksperimentele periode was 100 dae, waartydens elke koei elke behandeling vir 18 dae ontvang het voor die datakolleksieperiode van 7 dae. Rumen pH is voortdurend, elke vier minute, oor ‘n twee-dae periode gemeet met behulp van draagbare dataloggers en pH elektrodes wat binne-in die rumen gesetel was. Rumenvloeistof is versamel vir die bepaling van vlugtige vetsuurkonsentrasies. Gedurende elk van die datakolleksieperiodes is die melkproduksie twee maal per dag geneem vir sewe agtereenvolgende dae en melkmonsters is tweemaal per dag versamel vir vyf agtereenvolgende dae vir komponent–analise (samestelling?). Koeie is ad libitum gevoer en voerinnames is individueel bepaal. Die behandelings het geen betekenisvolle invloed op melkproduksie, melksamestelling of voerinnames gehad nie. Rumen pH profiele van al die behandelings het aangedui dat die diëte goed gebuffer was. Die gemiddelde pH oor 24 uur was 6.0, 6.1, 6.1 en 6.2 vir Behandeling 1, 2, 3 en 4, onderskeidelik. Die pH het nie onder 5.8 gedaal vir enige van die behandelings nie en die toenemende vlakke van natriumbikarbonaat het ‘n verhoging in die daaglikse pH-profiele tot gevolg gehad. By die hoogste buffervlakke (Behandeling 4) het die pH-profiel tussen 6.1 en 6.5 gevarieer. Hoewel nie betekenisvol nie, het Behandeling 1 (slegs Acid Buf) numeries die hoogste melkproduksie getoon, sonder dat melkkwaliteit beïnvloed is. Dit is voorgestel dat te hoë rumen pH ‘n nadelige impak op melkproduksie kan hê, as gevolg van ‘n verhoogde asetaat:propionaat verhouding wat rumen doeltreffendheid benadeel. Behandelings het geen betekenisvolle invloed op totale vlugtige vetsuurkonsentrasies gehad nie, maar daar was ‘n neiging vir hoër totale vlugtige vetsuurkonsentrasies namate die vlakke van natriumbikarbonaat verhoog het. Die asetaat:propionaat verhouding van Behandeling 1 (2.91) was betekenisvol laer as dié van Behandeling 4 (3.65). Die gebruik van buffers wat reageer op toenemende suurheidsgraad kan dus aangewend word as ‘n doeltreffende en veilige oplossing vir rumen asidose. Die studie het bevestig dat ‘n daaglikse inname van 80 g Acid Buf deur koeie wat ‘n hoë kragvoerdieet ontvang, hoë melkproduksie ondersteun sonder dat melksamestelling nadelig beïnvloed word.

Einleitung: Monocarboxylattransporter (MCT) 1 & 4 sind in zahlreichen Geweben als Kotransporter für Monocarboxylate und Protonen beschrieben. Auch im Pansenepithel werden MCT benötigt, um kurzkettige Fettsäuren (SCFA) aus dem Pansenlumen in die Pansenepithelzelle aufzunehmen (MCT4) und um SCFA und deren Metabolite aus der Pansenepithelzelle in das Blut auszuschleusen (MCT1). Die transepitheliale Permeation von SCFA über die Pansenwand ist von enormer Bedeutung, da sie die wichtigste Energiequelle der Wiederkäuer darstellen. Die beteiligten Transportprozesse müssen dementsprechend einer Anpassung an variierende Mengen von SCFA unterliegen. Bisherige Studien bei anderen Spezies deuten auf eine Regulation des MCT1 auf mRNA Ebene über den Peroxisom-Proliferator-aktivierten Rezeptor α (PPARα) hin. Ziele der Untersuchung: Das Ziel dieser Arbeit war herauszufinden, ob MCT1 in ovinen Pansenepithelzellen über PPARα reguliert wird und ob auch MCT4 dieser Regulation unterliegt. Eine gleichzeitige Regulation beider Transporter läge nahe, da sie gemeinsam an der transepithelialen Permeation beteiligt sind. Die Auswirkungen solch einer Regulation auf die Proteinexpression und die Transportleistung der MCT sollte charakterisiert werden. Ebenfalls war das Potenzial der bei erhöhter Kraftfutterfütterung vermehrt anfallenden SCFA Butyrat auf die MCT1 Expression zu untersuchen. Material & Methoden: Aus dem Vorhof von Schafen wurden Pansenepithelzellen gewonnen und entsprechend einer bereits etablierten Methode kultiviert. Nach einer Subkultivierung wurden die Zellen immunzytochemisch mit Antikörpern gegen MCT1, MCT4 und Na+/K+-ATPase untersucht, um deren Lokalisation in den kultivierten Pansenepithelzellen zu bestimmen. Weiterhin erfolgte eine Behandlung mit WY 14.643, einem spezifischen, synthetischen PPARα Agonisten, sowie mit GW 6471, einem Antagonisten des PPARα. Mittels qPCR wurden die relativen mRNA Mengen von MCT1, MCT4, ACO, CPT1A und CACT bestimmt und auf die Referenzgene GAPDH und Na+/K+-ATPase normalisiert. Die Proteinexpression von MCT1 und MCT4 wurde mittels Western Blot bestimmt. Zur funktionellen Quantifizierung wurde der intrazelluläre pH-Wert der Zellen mittels Spektrofluorometrie gemessen und der laktatabhängige Protonentransport als Vergleichswert zwischen den Behandlungen genutzt. Um den MCT-abhängigen Teil des Transportes zu bestimmen, wurde ein spezifischer MCT1 & 4 Inhibitor, die p-Hydroxymercuribenzensulfonsäure (pHMB) eingesetzt. Die Zellen wurden mit Butyrat über einen Zeitraum von 6 und 48 h induziert. Die Erfassung der MCT1 Expression erfolgte mittels semiquantitativer PCR. Ergebnisse: MCT1 & 4 sind sowohl in der Zellmembran als auch intrazellulär in den Pansenepithelzellen lokalisiert. Die mRNA Expressionsdaten konnten zeigen, dass MCT1 und die PPARα Zielgene durch WY 14.643 hochreguliert werden konnten, wohingegen die MCT4 Expression keine eindeutige Antwort auf die Stimulation zeigt. Die Behandlung mit den Antagonisten zeigt eine Abhängigkeit der MCT1 Expression von PPARα, die MCT4 Expression konnte dagegen nicht beeinflusst werden. Mittels pHMB gelang es, den laktatabhängigen Protonenexport fast vollständig zu blocken. Sowohl laktatabhängiger Protonenexport als auch die Proteinexpression zeigten keine Änderung durch WY 14.643 Stimulation. Die Butyratexposition veränderte die Morphologie der Pansenepithelzellen und schien nicht geeignet für Untersuchungen der mRNA Expression zu sein. Schlussfolgerungen: Es konnte in dieser Arbeit erstmals gezeigt werden, dass MCT1 in Pansenepithelzellen über PPARα reguliert wird, nicht aber MCT4. PPARα scheint demnach einer der entscheidenden Angriffspunkte für die Regulation des SCFA Transportes zu sein, dessen natürliche Liganden im Pansen aber noch nicht bekannt sind. Damit legt diese Arbeit den Grundstein für regulative Studien am intakten Pansenepithel. / Introduction: Monocarboxylate transporters (MCT) 1 & 4 are cotransporters of monocarboxylates and protons in a variety of mammalian cell types. In the ruminal epithelium MCT are necessary to transport short-chain fatty acids (SCFA) from the lumen into the ruminal epithelial cell (MCT4) and to discharge SCFA and their metabolites from the cell into the blood (MCT1). Transepithelial permeation of SCFA is of great importance, because they are the main source of energy for ruminants. The regulation of appropriate transport proteins should thus be subject to the adaptation to varying SCFA amounts. Previous studies in other species suggested that gene expression of MCT1 is regulated by peroxisome proliferator-activated receptor α (PPARα), a ligand-activated nuclear receptor. Aims: The aim of the study was to examine if MCT1 in ruminal epithelial cells is regulated by PPARα and furthermore if MCT4 can be regulated by PPARα, as well. A simultaneous regulation seems likely, because both are acting jointly in the transepithelial transporting of SCFA. The implications of such a regulation on protein expression and transport capacity of MCT should be characterized. The effect of butyrate, a SCFA which increases under concentrate feeding, on MCT1 expression was determined. Materials & Methods: Ruminal epithelial cells of sheep were cultivated according to methods previously established. After subcultivation, immunocytochemistry with antibodies against MCT1, MCT4 and Na+/K+-ATPase was performed to determine their localization in ruminal epithelial cells. For studying the influence of PPARα, WY 14.643, a synthetic and selective ligand of PPARα, and GW 6471, a synthetic antagonist of PPARα, were applied to the culture medium of the cells. After processing the specimens, the relative amount of mRNA of MCT1, MCT4 and the target genes ACO, CPT1A and CACT were analyzed by qPCR and normalized on the reference genes GAPDH and Na+/K+-ATPase. Protein abundance of MCT1 & 4 was measured by using the Western Blot method. Functional quantification was measured by the intracellular pH (pHi) of cells using spectrofluorometry as well as comparing the effect of WY 14.643 treatment on lactate-dependent proton export. To determine the MCT-dependent part of the pHi recovery, p-hydroxymercuribenzoic acid (pHMB), a specific inhibitor of MCT1 & 4, was applied. Cells were also treated with butyrate for 6 h and 48 h and the mRNA abundance of MCT1 was analyzed by semiquantitative PCR. Results: Both MCT1 and MCT4 were localized in the cell membrane as well as in the cytoplasm of ruminal epithelial cells. By qPCR it could be demonstrated that the mRNA abundance of MCT1 and PPARα target genes in the ruminal epithelial cells was increased by WY 14.643 in comparison to untreated cells, whereas the response of MCT4 did not yield distinct results. Treatment with the PPARα antagonist pointed out, that MCT1 is influenced by PPARα, but not MCT4. Lactate-dependent proton export was blocked almost completely by pHMB. Both lactate-dependent proton export and protein expression were not altered by WY 14.643 treatment. Butyrate exposure changed the morphology of ruminal epithelial cells and seemed unsuitable for the analysis of mRNA expression. Conclusion: For the first time, it could be demonstrated, that MCT1 in ruminal epithelial cells is regulated by PPARα, but not MCT4. PPARα seems to be a vital target in the rumen for SCFA transport regulation, whose natural triggers have yet to be identified. Furthermore, this study provides the basis for regulative studies on intact ruminal epithelium.

Foram realizados dois experimentos com o objetivo de avaliar o efeito da substituição parcial do milho pela casca de soja (CS) sobre o desempenho, o comportamento ingestivo, as características da carcaça, a digestibilidade aparente dos nutrientes, o balanço de nitrogênio, os parâmetros ruminais e sangüíneos de cordeiros da raça Santa Inês. O tratamento controle (CS0) foi uma ração contendo 70% de milho (% da MS), sendo o milho substituído em 15%, 30% e 45% pela CS, constituindo os tratamentos CS0, CS15, CS30 e CS45, respectivamente. As rações experimentais foram isonitrogenadas (19,12 ± 0,60% de PB), contendo 90% de concentrado e 10% de feno de \"coastcross\" (Cynodon sp.). No Experimento I (digestibilidade, balanço de nitrogênio, parâmetros ruminais e sangüíneos): foram utilizados 16 cordeiros, canulados no rúmen com peso médio inicial de 44,3 ± 5 kg e aproximadamente 6 meses de idade, distribuídos em delineamento experimental de blocos completos casualizados. O consumo de MS, MO, FDN, FDA e PB em kg/dia e g/kg de PC0,75, bem como o consumo de NDT em kg/dia, de ED em Mcal/dia aumentaram linearmente (P < 0,05) com a inclusão de CS. A retenção de nitrogênio reduziu linearmente (P < 0,05) e a concentração de propionato no fluido ruminal apresentou efeito quadrático (P < 0,05), tendo-se máxima concentração no tratamento CS15. Enquanto que, o consumo de EE g/kg de PC0,75, os valores de NDT em % da MS, a concentração de ED em Mcal/kg de MS, os coeficientes de digestibilidade aparente da MS, CNF, PB e EE, e a concentração total dos AGCC e de amônia no fluido ruminal não foram afetados pelos tratamentos. No experimento II (desempenho, características de carcaça e comportamento ingestivo): foram utilizados 64 cordeiros com peso inicial de 18,3 ± 2,8 kg e idade de 69 ± 5 dias, distribuídos em delineamento experimental de blocos completos casualizados, com dois animais por baia e 8 baias por tratamento. O GMD, as características da carcaça e os tempos gastos com as atividades de ingestão (min/g de MS), ruminação (min/dia e min/g de MS) e mastigação (min/dia) não foram afetados pelos tratamentos. O consumo de MS e de FDN, a CA, e os tempos gastos com ruminação (min/g de FDN) e mastigação (min/g de MS) aumentaram linearmente (P < 0,05) com a inclusão de CS. A inclusão de CS na ração, em substituição parcial ao milho, aumentou o consumo dos nutrientes e de energia digestível, e melhorou o pH ruminal, sem afetar o GMD e as características da carcaça dos cordeiros. Entretanto, reduziu a retenção de nitrogênio e piorou a CA. / Two experiments were conducted to evaluate the effects of partial replacement of corn by soybean hulls (SH) on performance, carcass characteristics, ingestive behavior, apparent digestibility of nutrients, nitrogen balance and ruminal and blood parameters of Santa Ines lambs. The control treatment (SH0) was a diet containing 70% of corn on a DM basis. On the others diets corn was replaced by SH at 15, 30 and 45%, corresponding to the experimental treatments SH0, SH15, SH30 and SH45, respectively. All diets were isonitrogen (19.12 ± 0.60% of CP), containing 90% of concentrate and 10% \"coastcross\" hay (Cynodon sp.). In Trial 1 (apparent digestibility of nutrients, nitrogen balance, ruminal and blood parameters), sixteen Santa Ines ram lambs (BW 44.0 ± 5.0 kg and 6 months old) were allotted individually in suspended metabolism crates, assigned to a complete randomized block design. DM, OM, NDF, ADF and CP intake (kg/day and g/kg of BW0,75), and also TDN intake (kg/day), DE intake (kg/day), increased linearly (P < 0.05) with SH addition. Nitrogen retention decreased linearly (P < 0.05) and propionate concentration (mM) showed a quadratic response (P < 0.05). There was no effect on EE intake (g/kg of BW0,75), TDN values (% of DM), DE concentration (Mcal/kg of DM), apparent digestibility of DM, NFC, CP, EE, and ruminal ammonia and total SCFA concentrations. In Trial 2 (performance, carcass characteristics and ingestive behavior), sixty-four Santa Ines lambs (BW 18,3 ± 2,8 kg and 69 ± 5 days old) were penned (2/pen) and used in a complete randomized block with four treatments and eight replicates. ADG, carcass characteristics and the times expended in ingestion (min/g of DM), rumination (min/day and min/g of DM) and chewing (min/day) activities there was no effect treatments. DMI and NDF intake, FC and the times expended in rumination (min/g of NDF) and chewing (min/g of DM) increased linearly (P < 0.05) with SH addition. SH inclusion in the diet at replacing corn, increased nutrients and DE intake and improved ruminal pH. with no detrimental effect on ADG and carcass characteristics. However, decreased nitrogen retention and worsened the FC.

Foram conduzidos dois experimentos com objetivo de avaliar o efeito da substituição do milho moído por diferentes co-produtos da indústria sobre o desempenho e metabolismo de bezerros em aleitamento. No primeiro experimento, 24 bezerros da raça Holandês foram distribuídos em três tratamentos, de acordo com o nível de inclusão de polpa cítrica desidratada (PC): (1) concentrado contendo 64% de milho e 0% de PC (0PC); (2) concentrado contendo 32% de milho e 32% de PC (50PC); e (3) concentrado contendo 0% de milho e 64% de PC (100PC). No segundo experimento, 36 bezerros da raça Holandês foram distribuídos em quatro tratamentos, de acordo com o nível de inclusão de melaço de cana líquido (ME) e xarope de glicose (XG): (1) concentrado contendo 65% de milho, 0% de ME e 0% XG (0ME); (2) concentrado contendo 60% de milho e 5% ME (5ME); (3) concentrado contendo 55% de milho e 10% de ME (10ME); e (4) concentrado contendo 60% de milho e 5% de XG (5XG). Os animais de ambos os experimentos receberam diariamente 4 L de sucedâneo lácteo, além de concentrado e água ad libitum. O consumo do concentrado e o escore fecal foram controlados diariamente. Semanalmente os animais foram pesados e tiveram as medidas corporais aferidas. Amostras de sangue foram colhidas semanalmente para determinação de glicose, lactato e ?-hidroxibutirato. Amostras de fluído ruminal foram colhidas nas semanas 4, 6 e 8 para determinação de pH, N-amoniacal e ácidos graxos de cadeia curta (AGCC). Na oitava semana de vida os animais foram abatidos para avaliação do desenvolvimento do trato digestório superior (peso e volume dos compartimentos e tamanho, área e número das papilas ruminais). No primeiro experimento não houve diferença entre tratamentos (P>0,05) para as variáveis de consumo, desempenho, parâmetros sanguíneos e ruminais, exceto para a concentração de butirato, onde os tratamentos 50PC e 100PC apresentaram maior (P<0,05) concentração que 0PC. Este resultado está relacionado ao maior (P<0,05) peso do trato digestório superior total, maior proporção do retículo-rúmen e área das papilas ruminais dos tratamentos com inclusão de PC, uma vez que o butirato é o principal AGCC estimulador do desenvolvimento ruminal. Dessa forma, a substituição parcial ou total do milho por PC no concentrado inicial não altera o desempenho de bezerros leiteiros, podendo ainda apresentar efeitos positivos no metabolismo ruminal e desenvolvimento do trato digestório superior. No segundo experimento não houve efeito de tratamento (P>0,05) para as variáveis de consumo, desempenho e escore fecal. Porém, observou-se aumento (P<0,05) na concentração total de AGCC, acetato e propionato do tratamento 5ME quando comparado à 0ME, sendo que os demais não diferiram de 5ME e 0ME. Essa alteração no metabolismo ruminal não foi acompanhada (P>0,05) por mudanças nos parâmetros sanguíneos ou de desenvolvimento do trato digestório superior. Pode-se concluir que a substituição do milho por 5 e 10% de ME ou 5% de XG no concentrado não prejudica o desenvolvimento corporal de bezerros leiteiros, sendo uma alternativa ao uso do milho na composição de dietas sólidas para esta classe animal. / Two studies were conducted to evaluate the effect of replacing corn grain by co-products, on the performance and changes in the metabolism of dairy calves. In the first study, 24 Holstein calves were divided into three groups, according to level of inclusion of citrus pulp (CP): (1) starter containing 64% corn and 0% CP (0CP), (2) starter containing 32% corn and 32% CP (50CP), and (3) starter containing 0% corn and 64% CP (100CP). In the second study, 36 Holstein calves were allocated four treatments according to level of inclusion of liquid sugar cane molasses (MO) or glucose syrup (GS): (1) starter containing 65% corn, 0% MO and 0% GS (0MO), (2) starter containing 60% corn and 5% MO (5MO), (3) starter containing 55% corn and 10% MO (10MO), and (4) starter containing 60% corn and 5% GS (5GS). The animals of both experiments received 4 L milk replacer daily. Starter and water were provided ad libitum. Starter intake and fecal score were monitored daily. Weekly, the animals were weighed and had their body measurements monitored until eight weeks. Blood samples were taken weekly for glucose, lactate and ?-hydroxybutyrate analysis. Ruminal fluid samples were collected at weeks 4, 6 and 8 of age to pH, ammonia-N and short chain fatty acids (SCFA) determination. In the eighth week of life animals were slaughtered to evaluate the development of the upper digestive tract (weight and volume of the compartments, as well as size, area and number of ruminal papillae). In the first experiment there were no differences among treatments (P>0.05) for starter intake, performance, ruminal and blood parameters, except for the concentration of butyrate, where treatments 50CP and 100CP had higher concentration (P<0.05) than 0CP. This result is related to the higher (P<0.05) weight of total upper digestive tract, proportion of the reticulum-rumen and rumen papillae area of treatments including CP, since butyrate is the main SCFA stimulating rumen development. Thus, the partial or total replacement of corn by citrus pulp in the starter does not change the performance of calves, and may present positive effects on ruminal metabolism and development of the upper digestive tract. In the second study there was no effect of the starter composition (P>0.05) for starter intake, performance or fecal scores. However, there was an increase (P<0.05) in the total SCFA, acetate and propionate concentration for treatment 5MO compared to 0MO, whereas the other treatments did not differ from 5MO and 0MO. This change in ruminal metabolism was not accompanied (P>0.05) by changes in blood parameters and development of the upper digestive tract. It may be concluded that the substitution of corn for 5 and 10% MO or 5% GS in the starter has no detrimental effect on body development of dairy calves, being an alternative to the use of corn in solid feed composition for these animals.

O objetivo deste estudo foi avaliar o efeito da substituição de milho por glicerina bruta no concentrado inicial, sobre o desempenho e alterações no metabolismo energético de bezerros em aleitamento. Vinte e quatro bezerros da raça Holandês recém-nascidos foram alojados em abrigos individuais até a 8a semana de vida, com livre acesso à água, sendo alimentados com 4 litros de sucedâneo/dia e concentrado ad libitum. Os animais foram distribuídos em blocos casualizados de acordo com a data de nascimento e peso ao nascer, e alocados em um dos seguintes tratamentos, de acordo com a inclusão de glicerina em substituição ao milho no concentrado inicial: 1) 0% Glicerina bruta; 2) 5% Glicerina bruta; 3) 10% Glicerina bruta. O aleitamento foi realizado duas vezes ao dia (07 e 17h) com sucedâneo comercial (22% proteína bruta; 19% extrato etéreo). O consumo de concentrado inicial e o escore fecal foram registrados diariamente, enquanto que a pesagem e as medidas de altura na cernelha, perímetro torácico e largura da garupa foram realizadas semanalmente, a partir da segunda semana, até a oitava semana. A partir da segunda semana, foram realizadas colheitas semanais de amostras de sangue, duas horas após o aleitamento da manhã, para determinação das concentrações plasmáticas de glicose, lactato, proteínas totais e &beta;-hidroxibutirato (BHBA). Nas semanas 4, 6 e 8 de idade foram colhidas amostras de fluido ruminal, utilizando-se sonda oroesofágica e bomba a vácuo, para determinação do pH e ácidos graxos de cadeia curta (AGCC). Na oitava semana, se encerrou o período experimental e os animais foram abatidos para avaliação do desenvolvimento do trato digestório superior e de papilas ruminais. O consumo de concentrado inicial, o ganho de peso diário e o peso vivo não apresentaram diferenças (P>0,05) entre os tratamentos. As medidas corporais, não apresentaram diferenças significativas (P>0,05). A média encontrada dos escores fecais durante todo o período experimental sugere baixa frequência de diarreia nos animais. Dentre os parâmetros ruminais avaliados, apenas o propionato e a relação acetato:propionato foram afetados (P<0,05) pelos tratamentos, apresentando menores valores de propionato em animais consumindo concentrado com 5% de glicerina bruta e menor relação acetato:propionato encontrados para os animais recebendo glicerina, este último em resposta ao tipo de fermentação do glicerol. Os parâmetros sanguíneos avaliados (glicose, BHBA, lactato e proteínas totais), não foram afetados pelos diferentes tratamentos (P<0,05), apresentando valores adequados. O peso total do trato digestório superior, os pesos médios de cada compartimento e a capacidade máxima do retículo-rúmen não foram afetados pelos tratamentos, assim como os parâmetros de desenvolvimento do epitélio ruminal. A glicerina pode ser utilizada como ingrediente energético alternativo até a taxa de 10% de substituição ao milho do concentrado inicial de bezerros leiteiros no período de aleitamento sem afetar o crescimento, o desenvolvimento ou o metabolismo do animal. / The purpose of this study was to evaluate the effect of the replacement of corn by crude glycerin in the starter concentrate on performance and energy metabolism of dairy calves. Twenty-four newborns Holstein calves were housed in individual shelters until the eighth week of age, fed 4 liters of milk / day and ad libitum water and concentrate. The animals were distributed in randomized blocks according to the birth date and birth weight, and assigned to one of the following treatments, in accordance with the inclusion of glycerin replacing corn in the starter concentrate: 1) 0% Crude glycerin, 2) 5% Crude glycerin; 3) 10% Crude glycerin. Milk-feeding was performed twice daily (07 and 17h) with commercial milk replacer (22% crude protein, 19% ether extract). The initial feed intake and fecal scores were recorded daily, while weighing and measurements of height at withers, heart girth and hip width were measured from second week to eighth week. From the second week of age, blood samples were collected once a week, two hours after morning feeding, for determination of plasma glucose, lactate, total proteins and &beta;-hydroxybutyrate (BHBA) concentrations. Ruminal fluid was collected at 4, 6 and 8 weeks using an oro-ruminal probe and a suction pump for determination of pH and short-chain fatty acids (SCFA). At the end of eighth week of life, animals were slaughtered to evaluate development of the upper digestive tract and rumen papillae. Feed intake, average daily gain and body weight did not differ (P>0.05) among treatments. No differences was observed for body measurements (P>0.05). The fecal scores suggested low frequency of severe diarrhea in animals. Among the ruminal parameters, only propionate and acetate: propionate ratio were affected (P<0.05) by treatments, with smaller amounts of propionate for animals fed concentrate containing 5% of crude glycerin; and lower acetate: propionate ratio for animals receiving glycerin, because of the type of glycerol fermentation. Blood parameters (glucose, BHBA, total protein and lactate) were not affected by treatments (P<0.05), presenting adequate values. The total forestomach weight, the average weight of each compartment and the maximum capacity of reticulum-rumen were not affected by treatments, as well as the parameters for ruminal epithelium development. Crude glycerin can be used as an alternative energy source replacing corn up to 10% in the starter concentrate for milk-feeding dairy calves without affecting growth, development or animal metabolism.

O objetivo desse estudo foi avaliar o desempenho, o perfil de ácidos graxos e os parâmetros ruminais de ovinos alimentados com co-produtos da indústria citrícola em rações contendo alta proporção de concentrado. Adicionalmente, foram comparadas as estimativas de desempenho e de metabolismo obtidas nos experimentos com as preditas pelo modelo SRNS Small Ruminant Nutrition System No experimento I, 28 ovelhas foram alimentadas com ração composta por 55% de milho na matéria seca (MS), sendo o milho substituído em 33%, 67% e 100% pela polpa cítrica desidratada (PCD). Houve diminuição linear (P<0,02) no consumo de matéria seca (CMS) à medida que a PCD substituiu o milho, entretanto, não houve efeito na produção de leite. Não houve alteração dos componentes do leite, com exceção do teor de uréia que diminuiu linearmente (P<0,01). Em relação ao perfil de ácidos graxos (AG) no leite das ovelhas foi verificado aumento linear (P<0,05) de C15:0, C16:0, C17:1, C18:3, AG de cadeia média e saturados, e diminuição linear (P<0,05) de C18:0, C18:1, C18:2 t10,c12, AG monoinsaturados e de cadeia longa. Para o C18:2 c9,t11 houve aumento de 47% quando a PCD substituiu o milho em 33%. No experimento II, 32 cordeiros foram alimentados com ração contendo 90% de concentrado, sendo o milho substituído pela PCD em 33, 67 e 100%, respectivamente. A substituição total do milho pela PCD promoveu aumento (P<0,03) de 177% na concentração de C18:3, enquanto que a substituição parcial (33%) resultou em aumento (P<0,02) de 72% no C18:2 c9,t11. Adicionalmente, ocorreu diminuição linear (P=0,02) do extrato etéreo com a adição de PCD na ração. No experimento III, na avaliação de desempenho, 64 cordeiros foram alimentados com rações contendo 69,5% de PCD, sendo esta substituída em 30% na MS pela polpa cítrica úmida semi despectinada in natura (PCUD), ensilada (PCUDS) ou ensilada com adição de benzoato de sódio (PCUDS+B). Não houve diferença no CMS e no ganho médio diário (GMD). No entanto, a eficiência alimentar foi maior para os cordeiros alimentados com PCUD comparados àqueles recebendo ração contendo PCD. Na avaliação da digestibilidade e de parâmetros ruminais, 16 cordeiros, canulados no rúmen foram alimentados com rações contendo 75,3% de PCD, sendo esta substituída em 30% na MS pela PCUD, PCUDS ou PCUDS+B. Não houve diferença nos coeficientes de digestibilidade para MS, MO e PB, com exceção para o da FDN que foi maior (P<0,05) para a PCUD comparada à PCD. A concentração de amônia no fluido ruminal foi maior (P<0,01) para as rações contendo PCD comparada à PCUDS e PCUDS+B. No experimento IV, 24 cordeiros foram alimentados com rações contendo 70% de PCD na MS e tiveram a adição de 0; 0,3; 0,6 e 0,9% de monoamônio fosfato (MAP). Houve diminuição linear (P<0,01) no CMS e GMD com a inclusão de MAP na ração. No experimento V foi observada melhor predição de CMS para os cordeiros em relação às ovelhas. / The objective of this study was to evaluate the performance, fatty acids (FA) profile and ruminal measures of sheep fed citrus coproducts in diets containing high concentrate. Additionally, the performance and metabolic estimates from SRNS model - Small Ruminant Nutrition System were compared to experimental data. In Experiment I, 28 ewes were fed diet containing 55% of corn. Dried citrus pulp (DCP) was added at 18.1, 36.8 and 55% (diet DM) replacing corn by 33, 67 and 100%, respectively. There was a linear decrease (P<0.02) in dry matter intake (DMI) with DCP inclusion, however, there was no effect on milk production. Milk composition, was not affected by DCP inclusion, except for urea that showed a linear (P<0.01) decrease. Milk FA increased linearly for C15:0, C16:0, C17:1, C18:3, medium-chain and saturated FA and decreased linearly for C18:0, C18:1, C18:2 t10,c12, monounsaturated and long-chain FA when DCP replaced corn. There was a 47% increase for C18:2 c9,t11 when DCP replaced corn by 33%. In Experiment II, 32 Santa Ines lambs were fed a 90% concentrate. DCP was added at 23.7, 46.1 and 68.4% (on a DM basis) replacing corn by 33, 67 and 100%, respectively. Total replacement of corn by DCP promoted an increase (P<0.03) by 177% in linolenic acid (C18:3) while a partial replacement showed an increase (P<0.02) by 72% in conjugated linoleic acid (C18:2 c9,t11). In addition, ether extract decrease (P=0.02) as DCP increased in the diet. In Experiment III, 64 lambs were fed diets containing 69.5% DCP. A portion (30%) of DCP on a DM basis was replaced by wet low pectin citrus pulp (WLPCP), wet low pectin citrus pulp silage (WLPCPS) or wet low pectin citrus pulp silage with sodium benzoate (WLPCPS+B). There were no differences in DMI and average daily gain (ADG). However, feed efficiency was greater for lambs fed WLPCP compared to lambs fed DCP. In the digestibility trial, 16 lambs, canulated in the rumen, were fed diets containing 75.3% DCP. A portion (30%) of the DCP was replaced by WLPCP, WLPCPS or WLPCPS+B. There was no difference (P>0.05) in dry matter, organic matter and crude protein apparent digestibilities, except for neutral detergent fiber digestibility (82.7 vs 73.3% for WLPCP and DCP, respectively). Additionally, ruminal ammonia concentration was higher (P<0.01) in diets containing DCP compared to WLPCPS and WLPCPS+B. In experiment IV, 24 Santa Ines lambs were fed diets containing 70% DCP and monoammonium phosphate (MAP) was added at 0, 0.3, 0.6, and 0.9% of the diet DM There was a linear decrease (P<0.01) in DMI and ADG. In experiment V DMI predictions were better estimated for lambs compared to DMI of ewes.

A produção de biodiesel vem crescendo ao longo dos anos e com ela o interesse por matérias-primas alternativas para produção. O pinhão manso e a mamona são consideradas promissoras pelo elevado teor de óleo nas sementes e potencial de utilização dos seus subprodutos na alimentação animal. Entretanto, o uso desses subprodutos é limitado devido à presença de ésteres de forbol (EF) no pinhão manso e de ricina na mamona. Nesse sentido, objetivou-se mensurar o teor de EF e ricina nos subprodutos do pinhão manso e da mamona, respectivamente, assim como avaliar o potencial de utilização desses subprodutos na alimentação de ovinos. O estudo foi desenvolvido em três experimentos. No experimento I os EF foram quantificados nas sementes e frações da semente de pinhão manso, assim como nas tortas e óleos após prensagem a frio das respectivas sementes e albumens. Os resultados mostraram que as tortas possuem perfil nutricional interessante para a dieta de ruminantes e que os EF foram concentrados no óleo após a prensagem, sugerindo que tortas com menor teor de óleo residual apresentem menores concentrações de EF. No experimento II, torta de mamona (TM) e torta de pinhão manso (TPM), destoxificada ou não, foram avaliadas em dois níveis de substituição ao farelo soja, 25 e 35% TPM e 25% e 50% TM, sobre os parâmetros de degradabilidade e fermentação ruminal in vitro. Após 24 horas de incubação foi observado que inclusão da TM e TPM, destoxificada ou não, não afetou a produção de gases total, a produção de N-NH3 e ácidos graxos de cadeia curta total (AGCC), indicando que a fermentação ruminal não foi afetada. Contudo, houve redução na concentração dos isoácidos com a inclusão de 50% de TM destoxificada, 35% de TPM e 25% de TPM destoxificada. A produção de metano foi reduzida com a inclusão de 35% de TPM não destoxificada, indicando que a presença de EF pode ter alterado a população de bactérias metanogênicas no liquido ruminal. No experimento III foi avaliada a substituição parcial do farelo de soja pela TM destoxificada sobre a eficiência de utilização dos nutrientes, microbiota ruminal e emissão de metano entérico de ovinos alimentados com esse subproduto. Os animais que receberam a dieta com TM destoxificada consumiram em média 0,59 mg de ricina kg-1 de peso corporal dia-1 e não apresentaram sintomas clínicos de intoxicação sequer alterações nos níveis séricos de enzimas relacionadas a função hepática e renal. A inclusão da TM destoxificada não influenciou no consumo dos animais, porém reduziu a digestibilidade dos nutrientes. A inclusão da TM destoxificada não alterou a síntese microbiana no rúmen, balanço de nitrogênio, parâmetros de fermentação ruminal e população microbiana em relação ao tratamento controle, com exceção do acetato, que aumentou com a inclusão da TM destoxificada, mas não refletiu sobre a emissão de metano ruminal. Apesar do potencial de substituição da torta de mamona destoxificada, a redução na digestibilidade aparente de alguns nutrientes podem refletir na redução do desempenho e aumento da produção de metano por kg de produto animal / Biodiesel production has been growing over the years and with it the interest for alternative raw materials for production. Jatropha and castor beans are considered to be promising because of the high oil content in seeds and potential of utilization of its by-products in animal feeding. However, these by-products usage is limited due to the presence of phorbol esters (PE) in jatropha and ricin in castor bean. In this sense, the objective was to measure PE and ricin content in by-products of jatropha and castor bean, respectively, as well as to evaluate the potential of utilization of these by-products in sheep feeding. The study was developed in three experiments. In the experiment I, PEs were quantified in seeds and fractions of jatropha seed, as well as in cakes and oils after cold-pressing of respective seeds and albumens. The results showed that the cakes have an interesting nutritional profile for ruminant diet and PEs were concentrated in the oil after pressing, suggesting that cakes with lower residual oil content showed lower PE concentrations. In the experiment II, castor cake (CC) and jatropha cake (JC), detoxified or not, were evaluated at two substitution levels of soybean meal, 25 and 35% of JC and 25% and 50% of CC, on the degradability and ruminal fermentation parameters in vitro. After 24 hours of incubation, it was observed that inclusion of CC and JC, detoxified or not, did not affect the total gas production, N-NH3 and total short chain fatty acids (SCFAs) production, indicating that ruminal fermentation was not affected. However, there was a reduction in isoacid concentration with the inclusion of 50% of detoxified CC, 35% of CC and 25% of detoxified JC. Methane production was reduced with the inclusion of 35% of non-detoxified JC, indicating that the presence of PE may have changed methanogenic bacteria population in the ruminal fluid. In the experiment III was evaluated the partial substitution of soybean meal by detoxified CC on the nutrient use efficiency, ruminal microbiota and enteric methane emission from sheep fed with this by-product. Animals that received diet with detoxified CC consumed on average 0.59 mg of ricin kg-1 body weight day-1 and did not showed clinical symptoms of intoxication even changes in serum levels of enzymes related to liver and renal function The inclusion of detoxified CC did not influence animal consumption, but it reduced the digestibility of nutrients. The inclusion of detoxified CC did not change rumen microbiota synthesis, nitrogen balance, ruminal fermentation parameters and microbial population in relation to the control treatment, with exception of acetate, which increased with detoxified CC inclusion, but did not reflect on ruminal methane emission. Despite the potential of replacement of detoxified castor cake, the reduction in apparent digestibility of some nutrients may reflect in performance reduction and increase in methane production per kg of animal product