ABSTRACT: This study evaluated forage-free diets supplemented with sodium bicarbonate (SB) based on ground flint corn on intake, apparent nutrient digestibility, ruminal parameters, and N balance. Four rumen-cannulatedDorper × Santa Inês lambs, with a body weight of 43.4 ± 0.85 kg (mean ± standard deviation) were used. The experimental design was a 4×4 Latin square. Each experimental period lasted 21 days. Experimental diets were: positive control, a diet without SB containing 400 g/kg DM of soybean hulls (CONT), and three diets based on ground flint corn, containing 10 (10SB), 20 (20SB) or 30 (30SB) g/kg DM of SB. Intake of neutral and acid detergent fiber was greater for CONT (P < 0.01) when compared to SB. Intake and apparent nutrient digestibility of dry and organic matter, ether extract, and crude protein did not differ. Intake (P = 0.01) and digestibility (P < 0.01) of non-fiber carbohydrates were greater for SB diets and neutral detergent fiber digestibility was greater (P = 0.03) for CONT. The total digestible nutrients and metabolizable energy were greater for SB (P = 0.04). Rumen concentrations of acetate (P < 0.01), isobutyrate (P < 0.01), butyrate (P < 0.01), isovalerate (P < 0.01), and total short-chain fatty acids (P < 0.01) were greater for CONT. Ruminal pH showed a quadratic (P = 0.05) response to SB levels, with greater values for 20SB. Sodium bicarbonate was efficient in increasing ruminal pH at the level of 20 g/kg DM without interfering with the intake and apparent nutrient digestibility characteristics.

RESUMO: O presente estudo avaliou a suplementação de bicarbonato de sódio (BS) em dietas sem forragem à base de milho moído sobre o consumo e a digestibilidade aparente dos nutrientes, os parâmetros ruminais e o balanço de N. Foram utilizados quatro cordeiros Dorper × Santa Inês, com um peso corporal inicial de 43,4 ± 0,85 kg (média ± desvio padrão). O delineamento experimental foi quadrado latino 4×4. Cada período experimental durou 21 dias. As dietas experimentais foram: controle positivo, sem BS, contendo 400 g/kg de MS de casca de soja (CONT) e três dietas à base de milho moído, sem casca de soja, contendo 10 (10BS), 20 (20BS) ou 30 (30BS) g/kg de MS de BS. O consumo de fibra em detergente neutro e ácido foi maior (P < 0,01)para o CONT quando comparado com BS. O consumo e a digestibilidade aparente da matéria seca, matéria orgânica, extrato etéreo e proteína bruta não diferiram entre os tratamentos. O consumo (P = 0,01) e digestibilidade (P < 0,01) dos carboidratos não fibrosos foram superiores para as dietas contendo BS e a digestibilidade da fibra em detergente neutro foi maior para o CONT. Os teores de nutrientes digestivos totais e energia metabolizável foram superiores para as dietas contendo BS (P = 0,04). A concentração ruminal de acetato (P < 0,01), isobutirato (P < 0,01), butirato (P < 0,01), isovalerato (P < 0,01) e ácidos graxos totais de cadeia curta (P < 0,01) foram mais elevadas para o CONT. O pHruminal apresentou resposta quadrática (P = 0,05) em relação aos níveis de BS, sendo observado maior pH para os animais alimentados com a dieta 20BS. O BS foi eficiente em aumentar o pHruminal no teor de 20 g/kg MS sem interferir no consumo e na digestibilidade aparente dos nutrientes. Portanto, 20 g/kg de MS é a dose indicada de BS em dietas sem forragem para terminação de cordeiros em confinamento.

ABSTRACT: Adding ionophores to ruminant diets is a strategy to manipulate ruminal fermentation and improve milk yield. This study evaluates the effects of narasin supply to lactating ewes on dry matter intake (DMI), milk yield and composition, and performance of the lambs. Thirty lactating Santa Inês and Santa Inês × Dorper ewes fed a basal diet containing 50 % coastcross hay and 50 % concentrate were randomly assigned to two treatments: control (CON; without ionophores) or NAR (addition of 13 mg narasin kg–1 DM). From the 2nd to 10th week of lactation, DMI of ewes was determined, and once a week, their milk production and composition was measured over a 3-h interval. At the 10th week of lactation, lambs were weaned and their average daily gain (ADG) and starter DMI continued to be evaluated for two more weeks. Narasin supply did not affect weight and DMI of ewes. Ewes fed NAR had greater feed efficiency for milk production and displayed tendency for higher milk yield. Narasin supply reduced milk protein levels, but it did not affect other milk component levels. Ewes fed NAR had greater production of milk urea nitrogen and showed tendency for higher production of fat and total solids. Starter DMI of lambs was not affected by treatments; however, there was a tendency for greater weaning weight for NAR lambs. At the end of experiment, no differences were observed in the performance of lambs. The supply of 13 mg narasin kg–1 to lactating ewes improved milk yield efficiency and tended to increase the weaning weight of their lambs.

ABSTRACT: Narasin is an antibacterial agent that may change rumen fermentation. Two experiments were proposed to evaluate the efficiency of narasin inclusion for lambs fed a diet containing high amounts of ground flint corn. Thirty rumen-cannulated wethers were used to evaluate nutrient digestibility, nitrogen balance, and rumen metabolism (Exp. 1); and forty-five lambs were used to evaluate performance (Exp. 2) of animals fed with narasin for high flint corn diets. The experimental diets were: control or basal diet without additives (C); 25 mg of monensin kg−1 of dry matter (DM) (M); and inclusion of 5 (N5), 10 (N10), and 15 (N15) mg of narasin kg−1 of DM. The statistical analyses were performed using the MIXED procedure of SAS. Monensin increased DM digestibility compared to C ( p = 0.01) and increasing doses of narasin linearly increased DM digestibility ( p < 0.01). There was a quadratic effect ( p = 0.10) for molar proportion of acetate peaking at N15. Monensin inclusion increased ( p = 0.07) propionate compared to C; however, it did not differ from narasin. The increasing levels of narasin linearly decreased the total volatile fatty acids concentration in the rumen ( p = 0.02). Monensin and C showed a similar performance. The increasing levels of narasin linearly increased ( p ≤ 0.04) average daily gain and feed efficiency. Monensin and narasin changed rumen fermentation and improved overall nutrient digestibility. However, lambs that received narasin showed improved performance when compared with animals that received M.

ABSTRACT Two experiments were proposed to evaluate the addition of monensin for lambs fed diets containing a high level of mature ground flint corn. The experimental diets were as follows: no inclusion of monensin (M0) and inclusion of 8 (M8), 16 (M16) and 24 mg kg–1 of monensin (M24). In experiment 1, eight cannulated wethers were divided into a double 4 × 4 Latin square experimental design to evaluate nutrient digestibility, plasma parameters and rumen fermentation. The experiment lasted 112 days, divided into four periods of 28 days each. In experiment 2, ninety-two lambs were used in a randomized block design to evaluate the performance over 56 days. In experiment 1, doses of monensin had no effect on nutrient intake (p ≥ 0.07) and digestibility (p ≥ 0.09). There was a quadratic effect for acetate molar proportion (p = 0.01), acetate to propionate ratio (p = 0.04) and rumen pH (p < 0.01). However, there was no effect on the molar proportion of propionate and butyrate. The monensin decreased linearly the total SCFA concentration (p < 0.01). The inclusion of monensin increased glucose (p < 0.01) and decreased lactate concentration in plasma (p = 0.05). In experiment 2, monensin decreased dry matter intake (p = 0.04). However, there was a quadratic effect for average daily gain (p = 0.03) and feed efficiency (p < 0.01), with the greatest values observed for the M8 diet. Thus, the inclusion of 8 mg kg–1 of dry matter diet (DM) improves ruminal fermentation and plasma parameters, resulting in greater growth performance in lambs.

Resumo: O objetivo deste trabalho foi avaliar a inclusão de narasina em suplementos mineral e proteico sobre o desempenho e o consumo de suplemento de novilhos de corte em pastagem. Cento e cinquenta novilhos Nelore com 17,0±0,06 meses de idade e 219,7±1,62 kg de peso inicial foram distribuídos em 30 unidades experimentais (UEs), com cinco animais cada uma. As UEs foram dispostas em 60 piquetes, os quais foram pastejados continuamente por 28 dias, seguidos de 28 dias de descanso. Utilizou-se o delineamento de blocos ao acaso. O tempo de duração do experimento foi de 140 dias, dividido em cinco períodos experimentais de 28 dias cada um. Os tratamentos avaliados foram: suplemento mineral controle (CON); CON + 1.800 (N1800) ou 2.750 (N2750) mg de narasina por quilograma de suplemento; e suplemento mineral proteinado (PROT) ou PROT + 360 mg de narasina por quilograma de suplemento (PROT 360). A inclusão de narasina na mistura mineral aumentou o ganho médio diário (GMD) durante o primeiro período e reduziu o consumo de suplemento no primeiro, no segundo e no terceiro períodos, quando comparado ao tratamento CON. O GMD e o consumo de suplemento foram semelhantes entre os tratamentos N1800 e N2750. A narasina tem efeito positivo no GMD até 28 de suplementação e controla o consumo de suplemento mineral, sem comprometer esse ganho.

Abstract: The objective of this work was to evaluate the effect of narasin inclusion in mineral and protein supplements on the performance and supplement intake of grazing beef yearlings. One hundred and fifty Nellore yearlings with 17.0±0.06 months of age and 219.7±1.62 kg initial body weight (BW) were allocated into 30 experimental units (EUs), with five animals each. The EUs were assigned to 16 paddocks, which were continuously stocked for 28 days, followed by 28 days of rest. A randomized complete block design was used. The experiment lasted 140 days, divided into five periods of 28 days each. The assessed treatments were: control mineral supplement (CON); CON + 1,800 (N1800) or 2,750 (N2750) mg narasin per kilogram of supplement; and protein mineral supplement (PROT) or PROT + 360 mg narasin per kilogram of supplement (PROT 360). The inclusion of narasin in the mineral supplement increased average daily gain (ADG) in the first period and decreased supplement intake in the first, second, and third periods, when compared with the CON treatment. The ADG and supplement intake were similar between the N1800 and N2750 treatments. Narasin has a positive effect on ADG up to 28 days of supplementation and controls mineral supplement intake, without compromising this gain.

The present study was conducted to investigate the effect of alternative true-protein sources to soybean meal, with different ruminal degradability, using a sugarcane-based diet, on nutrient digestion, ruminal fermentation, efficiency of microbial protein synthesis and passage rate in prepubertal dairy heifers. Eight crossbred rumen- and duodenum-cannulated Holstein × Gyr dairy heifers (202.0±11.5 kg BW) were evaluated in a 4 × 4 Latin square experimental design with four treatments and four periods in two simultaneous replicates. Dietary treatments were: soybean meal; cottonseed meal; peanut meal; and sunflower meal. When associated with diets containing sugarcane, the different protein sources did not affect intake or digestibility of dry mater, crude protein, organic matter and neutral detergent fiber. The average ruminal pH, NH3-N and concentration of total volatile fatty acids were not different among the diets supplied. The concentration of butyric acid was different among the protein sources, wherein the animals fed the diet with sunflower meal presented lower values than those fed the other sources. Diets did not affect nitrogen balance, microbial nitrogen, microbial synthesisefficiency, estimated dry matter flow, or passage rate. Alternative protein sources can be used to reduce the costs without changing the animal metabolism.

The objective of this study was to evaluate the characteristics of ruminal fermentation and enteric methane production in beef cattle subjected to different supplementation frequencies while grazing on Brachiaria brizanthacv. Marandu pastures. Nine cattle (325±65.7 kg BW) fitted with ruminal and duodenal cannulas were used in the ruminal fermentation study, and 12 cattle (399±32.6 kg BW) were used in the enteric methane production study. The treatments included supplementation once daily, supplementation once daily except Saturdays and Sundays, or supplementation on alternate days. The supplementation was equivalent to 10 g kg−1 BW day−1 for all treatments. The design employed was completely randomized with three treatments and three replications. When all supplements were provided (day 1), no effects of supplementation frequency were observed on ruminal pH; concentration of NH3-N; concentration of acetic, propionic, or butyric acids; or total volatile fatty acids (VFA), but there were month effects. During the day on which only daily supplements were provided (day 2), significant differences were observed only on the molar concentration of acetic acid and total VFA; and month effects were noted on all variables. No significant differences were observed in ruminal fluid volume, dilution rate, N intake, bacterial N synthesis and enteric methane production among the studied supplementation frequencies. Differences were observed in the enteric methane production in the different months, with 85 g kg−1 of gross energy intake observed in September and 123 g kg−1 of gross energy intake observed in November. Lower supplementation frequency is a good option to lower labor costs with little or no consequences on ruminal fermentation characteristics and enteric methane production.

The objective in this study was to determine growth, carcass characteristics, chemical composition and fatty acid profile of the longissimus dorsi of crossbred Boer × Saanen kids fed castor oil. Twenty-four kids (12 males and 12 females) were assigned in a randomized complete block design with two treatments and twelve replications. Blocks were defined according to weight, gender and initial age of animals for the evaluation of performance. The experimental treatments consisted of two diets containing 900 g concentrate/kg: a control diet (without addition of oil) and another containing castor oil at 30 g/kg (on a dry matter basis). After they reached an average body weight of 25 kg, males were slaughtered for the evaluation of carcass characteristics, chemical composition and fatty acid profile of the longissimus dorsi muscle. The addition of castor oil in the diet did not affect the intake of dry matter, crude protein and neutral detergent fiber; the average daily gain; and feed conversion, but increased the ether extract intake. No difference was observed for the carcass characteristics, chemical composition of the meat, concentration of C18:2 cis-9, trans-11 (CLA) and total concentration of saturated, monounsaturated and polyunsaturated fatty acids and their relations; however, there was increase in the concentrations of C18:2 trans-10, cis-12 (CLA) and C20:4 ω-6. The addition of castor oil to the diet of crossbred Boer × Saanen kids containing a high content of concentrate did not promote benefit to the characteristics evaluated.

The objective in this experiment was to determine the effects of feeding diets with canola, sunflower or castor oils on intake, nutrient apparent digestibility and ruminal constituents of crossbred Dorper × Santa Inês sheep. Four rumen-cannulated animals of 90.2±11.4 kg average body weight were assigned to a 4 × 4 latin square. Animals remained individually in cages for the metabolism assay and were fed diets containing roughage at 500 g/kg and concentrate based on ground corn and soybean meal also at 500 g/kg. No oil was added to the control diet, whereas the others had canola, sunflower or castor oils at 30 g/kg (DM basis). There was no difference for the intake of DM and nutrients, except for ether extract, which was greater when animals received oil. The digestibility coefficients of dry matter, organic matter, crude protein, non-fiber carbohydrates and neutral detergent fiber were not changed; however, the addition of oil increased the ether extract digestibility. The values of total digestible nutrients (TDN, g/kg of DM), digestible energy (DE, Mcal/kg of DM), TDN intake and DE intake also did not change with the addition of lipids. Concerning the ruminal constituents, the addition of vegetable oils reduced the concentrations of acetate, butyrate and total short-chain fatty acids. Adding canola, sunflower or castor oils at 30 g/kg in diets with 500 g roughage/kg and 500 g concentrate/kg does not impair the intake or digestibility of nutrients in sheep, although it reduces the concentration of short-chain fatty acids in the rumen.

Cinquenta e seis Escherichia coli isoladas de fezes diarreicas de carneiros (7 a 10 dias) no Estado de São Paulo, Brasil, foram avaliadas quando ao acúmulo de fluidos no intestino de camundongos recém-nascidos. Vinte e sete (48,2%) das amostras foram positivas para esse ensaio, porém nenhuma das 56 amostras foi capaz de induzir efeitos citopáticos em células Vero e CHO, indicando que não produzem toxinas LT ou VT. Análise por PCR mostrou que estas 27 E. coli foram positivas para estA, que codifica a proteína STa, mas não para os genes stx1, stx2 ou cnf. As amostras positivas para STa foram também analisadas quanto à presença dos genes que codificam as fímbrias F41, F17 e K99, fatores de colonização em ETEC. Somente F17 foi detectada em 2 amostras (7,4%). Doze das 27 E. coli STa positivas também contêm o gene hlyA e apresentaram atividade hemolítica em Agar sangue. Rotavírus não foi detectado nas fezes desses animais. Em conjunto, esses resultados sugerem que STa é um fator diarreiogênico importante para colibacilose de pequenos ruminantes no Estado de São Paulo.

Twenty seven (48.2%) culture supernatants of 56 Escherichia coli isolated from diarrheic lamb feces (7 to 10 days old) in São Paulo State, Brazil, presented positive results to suckling mice assay (fluid accumulation) but none caused cytopathic effects on Vero and CHO cells, indicating that these strains did not produced LT or VT toxins. PCR assays showed that these 27 E. coli strains harbored estA, that codifies for STa, but not for stx1, stx2 or cnf genes. The positive STa strains were checked for genes that codify for F41, F17 and K99 fimbriae, wich are considered colonization factors in ETEC. Only F17 was detect in two samples (7.4%). Twelve of 27 STa positive carried hlyA gene and presented hemolytic activity in blood Agar. Presence of rotavirus was not detected among the diarrheic feces. These data suggests that STa must be an important diarrheagenic factor to small ruminants in São Paulo State.

O objetivo neste experimento foi avaliar os efeitos do genótipo sobre a composição química e o perfil de ácidos graxos no músculo longissimus dorsi de borregas. Foram utilizados 36 animais dos grupos genéticos: Santa Inês (SI), Ile de France (IF), Ile de France × Santa Inês (IF × SI), Dorper × Santa Inês (DO × SI), Texel × Santa Inês (TE × SI) e Suffolk × Santa Inês (SU × SI). Os animais foram distribuídos em blocos completos casualizados, definidos de acordo com o peso e a idade inicial. Não houve efeito do genótipo sobre os teores de umidade, cinzas e proteína no músculo. A carne das borregas dos genótipos Santa Inês e Suffolk × Santa Inês apresentou menor teor de gordura em comparação à das borregas Ile de France e Ile de France × Santa Inês. Os ácidos graxos identificados em maiores proporções no músculo foram o ácido oleico (C18:1cis), ácido palmítico (C16:0) e ácido esteárico (C18:0). No grupo genético Ile de France × Santa Inês, a relação entre os ácidos graxos poliinsaturados e saturados foi menor que nas borregas Santa Inês e Suffolk × Santa Inês. O genótipo Santa Inês e o cruzamento Suffolk × Santa Inês tem potencial para produção de carne de melhor valor nutricional, devido ao menor teor de gordura e à melhor relação entre ácidos graxos poliinsaturados e saturados.

The objective in this study was to investigate the effects of genotype (breed) on the chemical composition and the fatty acid profile in the longissimus dorsi muscle of feedlot ewe lambs. Thirty-six ewe lambs were assigned to a randomized complete block design with the following genotypes: Santa Inês (SI), Ile de France (IF), Ile de France × Santa Inês (IF × SI), Dorper × Santa Inês (DO × SI), Texel × Santa Inês (TE × SI) and Suffolk × Santa Inês (SU × SI). Blocks were defined by initial weight and age. Genotype did not affect moisture, ash or protein content of the longissimus dorsi. Meat from SI and SU × SI ewe lambs showed less fat compared with IF and IF × SI. Oleic (C18:1cis), palmitic (C16:0), and stearic (C18:0) were the fatty acids found in largest amounts in the intramuscular fat in this study. The genetic group IF × SI showed smaller ratio between polyunsatured fatty acid (PUFA) and saturated fatty acid (SFA) when compared with SI and SU × SI ewe lambs. Santa Inês and Suffolk × Santa Inês crossbred animals showed potential to produce meat with higher nutritional value due to lower fat content and better ratio between polyunsaturated and saturated fatty acids.

O objetivo neste experimento foi avaliar os efeitos da substituição do feno de coastcross (Cynodon sp.) por casca de soja sobre a digestibilidade aparente dos nutrientes, os parâmetros ruminais e o metabolismo de nitrogênio. Dezesseis borregos (PV = 40,0±5 kg) foram individualmente alojados em gaiolas metálicas para ensaio de metabolismo em delineamento experimental do tipo blocos completos casualizados. O experimento teve duração de 14 dias, sendo 10 dias para adaptação dos animais às rações experimentais e 4 para coleta das amostras. Os animais foram alimentados com dietas compostas de 50% de volumoso e 50% de concentrado com mesmo teor de fibra em detergente neutro (FDN). A casca de soja substituiu o feno de coastcross em 0, 33, 67 ou 100% da matéria seca. Os teores de casca de soja na dieta tiveram efeito quadrático sobre os consumos de matéria seca e FDN. Contudo, observou-se aumento da digestibilidade da MS e FDN, enquanto a concentração de ácidos graxos de cadeia curta, acetato e propionato não se alteraram e o pH ruminal e a concentração de N-amoniacal diminuíram. A substituição parcial do feno de coastcross por casca de soja aumenta o consumo de matéria seca e diminui o pH ruminal sem prejudicar a digestibilidade da MS e FDN.

The objective of this experiment was to determine the effects of replacing coastcross hay (Cynodon sp.) by soybean hulls on nutrient apparent digestibility, ruminal measures and nitrogen metabolism. Sixteen ram lambs (40±5 kg of body weight) were housed individually in metabolism crates and assigned to a randomized completely block design. The experimental period consisted of 14 days; the first 10 days were used to adapt lambs to treatments and 4 other days for data collection. Animals were fed diets containing 50% concentrate and 50% roughage, both with the same amount of neutral detergent fiber (NDF). Soybean hulls replaced coastcross hay by 0, 33, 67 or 100% in the dry matter. Dry matter (DM) intake and NDF showed quadratic effect when soybean hulls were added to the diet. However, DM and NDF digestibility increased, while short-chain fatty acids, acetate and propionate concentration did not change and ruminal pH and ammonia decreased. Partially replacing coastcross hay by soybean hulls increases DM intake and lowers ruminal pH without affecting DM or NDF digestibility.

Objetivou-se com este trabalho verificar a resposta de cabras em lactação alimentadas com dietas contendo casca de soja em substituição ao feno de coastcross. Trinta e seis cabras (38±5 dias em lactação; 2,1±0,4 kg/dia) foram distribuídas em delineamento experimental de blocos completos casualizados e confinadas por oito semanas. As dietas foram compostas de 50% de volumoso e 50% de concentrado e com o mesmo teor de fibra em detergente neutro. A casca de soja substituiu o feno de coastcross em 0, 33, 67 ou 100% da matéria seca (MS). O consumo de matéria seca e a eficiência alimentar apresentaram resposta quadrática aos teores de casca de soja na dieta. A produção de leite e a variação do peso corporal não foram alteradas, porém a concentração de gordura e lactose do leite aumentou e os tempos gastos com ruminação e mastigação decresceram com a inclusão da casca de soja na dieta. A casca de soja pode substituir totalmente o feno de coastcross em dietas para cabras em lactação, pois essa substituição não prejudica a produção de leite e aumenta o teor de gordura e lactose do leite. Em comparação ao feno picado de coastcross, a casca de soja apresenta menor efetividade em estimular a ruminação e a mastigação.

The objective of this experiment was to verify the response of lactating goats fed diets with different levels (content) of soybean hulls replacing coastcross hay (Cynodon sp.) on performance. Thirty-six lactating Saanen goats (38±5 days of lactation; 2.1±0.4 kg/day) were assigned to a randomized complete blocks design and housed for 8 weeks. Goats were fed diets of 50% roughage and 50% concentrate, but with the same amount of neutral detergent fiber. Soybean hulls replaced hay by 0, 33, 67 or 100% of the dry matter (DM). Dry matter and NDF intake and feed efficiency showed a quadratic response to the levels of soybean hulls in the diet. Milk yield and body weight variations did not change; however, milk fat, lactose and total solids concentration increased while time spent with rumination and chewing decreased, when soybean hulls were added to the diet. Soybean hulls can replace entirely coastcross hay in diets for lactating goats, with no detrimental effect on milk yield or with an increase on milk fat and lactose concentration. Compared with chopped coastcross hay, soybean hulls show less effectiveness to stimulate rumination and chewing.

O objetivo neste estudo foi avaliar os efeitos da substituição parcial da polpa cítrica desidratada (PCD) pela polpa cítrica úmida semidespectinada in natura (PCUD), silagem de polpa cítrica úmida semidespectinada (PCUDS) ou silagem de polpa cítrica úmida semidespectinada adicionada de benzoato de sódio (PCUDS+B) sobre o desempenho, as características da carcaça, a digestibilidade aparente dos nutrientes, os parâmetros ruminais e o metabolismo de nitrogênio. Na avaliação de desempenho, 64 cordeiros Santa Inês foram alimentados com rações contendo 95% de concentrado e 5% de bagaço de cana-de-açúcar in natura durante 56 dias. O delineamento experimental utilizado foi o de blocos completos casualizados (BCC). A dieta controle continha 69,5% de PCD e foi substituída em 30% na matéria seca (MS) pela PCUD, PCUDS ou PCUDS+B. Não houve diferença no consumo de MS, no ganho médio diário de peso e nas características das carcaças. No entanto, a eficiência alimentar dos cordeiros alimentados com PCUD foi maior que a daqueles alimentados com PCD. No ensaio de metabolismo, 16 borregos Santa Inês, canulados no rúmen, foram distribuídos em BCC e alimentados com rações contendo 85% de concentrado e 15% de bagaço de cana-de-açúcar in natura. A dieta controle continha 75,3% de PCD e foi substituída em 30% na MS pela PCUD, PCUDS ou PCUDS+B. Não houve diferença nos coeficientes de digestibilidade da MS, matéria orgânica e proteína bruta. O coeficiente de digestibilidade da fibra em detergente neutro, porém foi maior para a PCUD comparado à PCD. A concentração de amônia no fluido ruminal foi maior para as rações contendo PCD em comparação àquelas com PCUDS e PCUDS+B. No entanto, para os demais parâmetros ruminais não foi verificado efeito dos tratamentos. A PCUD in natura ou ensilada pode substituir parcialmente a PCD em rações com alta proporção de concentrado para cordeiros em confinamento.

The objective of this study was to determine the effects of partial replacement of dried citrus pulp (DCP) 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) on performance and carcass characteristics, apparent digestibility of nutrients, ruminal measures, and nitrogen metabolism of lambs. In the performance trial, 64 Santa Inês ram lambs were fed 95% concentrate and 5% sugarcane bagasse diets during 56 days. The experimental design was a randomized complete block (RCB). The control diet contained 69.5% DCP, while in the other treatments fresh or ensiled WLPCP replaced DCP by 30% on a DM basis. There were no differences in DMI, ADG or carcass characteristics. However, feed efficiency was greater for lambs fed WLPCP compared with lambs fed DCP. In the digestibility trial, 16 Santa Inês ram lambs, canulated in the rumen, were assigned to a RCB design. Animals were fed diets containing 85% of concentrate and 15% of sugarcane bagasse. The control diet contained 75.3% DCP. A portion (30%) of the DCP DM was replaced by WLPCP, WLPCPS or WLPCPS+B. There was no difference in DM, organic matter or crude protein apparent digestibilities, except for neutral detergent fiber digestibility. Additionally, ruminal ammonia concentration was higher in diets containing DCP compared with WLPCPS and WLPCPS+B. Nevertheless, no effects of treatments were seen on the other ruminal measures. Fresh or ensiled WLPCP can partially replace DCP in rations with high level of concentrate for feedlot lambs.

Objetivou-se com esta pesquisa avaliar os efeitos da inclusão de monoamônio fosfato (MAP) em rações com alta proporção de concentrado contendo polpa cítrica sobre o desempenho e as características de carcaça de cordeiros em confinamento. Vinte e quatro cordeiros Santa Inês (26,4 kg de peso corporal e 125 dias de idade, em média) foram distribuídos em delineamento experimental de blocos completos casualizados, definidos de acordo com o peso e a idade no início do experimento. As rações foram isonitrogenadas, continham 70% de polpa cítrica na MS e tiveram a adição de 0; 0,3; 0,6 e 0,9% de MAP, correspondendo aos tratamentos CON, 0,3MAP, 0,6MAP e 0,9MAP, respectivamente. Houve diminuição linear no consumo de matéria seca e ganho diário médio de peso com a inclusão de MAP na ração, sem alteração nos parâmetros de carcaça avaliados. A utilização de MAP como fonte de fósforo em rações contendo polpa cítrica afeta negativamente o desempenho de cordeiros em confinamento.

The objective of this experiment was to evaluate the effects of adding monoammonium phosphate (MAP) in high concentrate diets containing citrus pulp on feedlot lamb performance and carcass characteristics. Twenty four Santa Ines lambs (26.4 kg of initial body weight and 125 d old) were penned individually and used in a randomized complete block design according to body weight and age at beginning of the trial. Diets were formulated to provide a similar amount of crude protein and contained 70% of citrus pulp on a DM basis. MAP was added at 0, 0.3, 0.6, and 0.9% of the diet DM corresponding to the experimental treatments CON, 0.3MAP, 0.6MAP, and 0.9MAP, respectively. There was a linear decrease in dry matter intake and average daily gain, although no changes on carcass measures were observed. The use of MAP in citrus pulp diets affects lamb growth negatively.