Ruminal degradable nitrogen for steers fed sugar cane: in situ degradability, ruminal parameters and microbial synthesis efficiency

Objetivou-se avaliar o efeito da deficiência de nitrogênio degradável no rúmen (NDR), utilizando como volumoso cana-de-açúcar suplementada com uréia, farelo de soja ou farelo de glúten de milho - 60, sobre a eficiência de síntese microbiana e a degradabilidade in situ da matéria seca (MS) e da fibra em detergente neutro (FDN) em novilhos mestiços. Utilizaram-se oito novilhos canulados no rúmen e duodeno, distribuídos em dois quadrados latinos 4 × 4 e alimentados com cana-de-açúcar e cana-de-açúcar suplementada com uréia, farelo de soja ou farelo de glúten de milho-60. O pH e a concentração de N-NH3 foram mensurados no fluido ruminal antes e 2, 4, 6 e 8 horas após o fornecimento da ração. Utilizou-se a fibra em detergente ácido indigestível como indicador de fluxo duodenal. A eficiência microbiana foi determinada pelas bases purinas.As fontes de proteína degradável no rúmen não influenciaram a degradabilidade da matéria seca, entretanto, o maior valor de degradabilidade efetiva da FDN foi obtido com a cana-de-açúcar com farelo de soja. O pH e a concentração de N-NH3 observados com todas as dietas foram adequados para o crescimento dos microrganismos ruminais. A deficiência de nitrogênio degradável no rúmen não influencia a síntese de proteína microbiana e a dinâmica de fase líquida.The objective of this work was to evaluate the ruminal degradable nitrogen (RDN) deficit using as roughage sugar cane supplemented with urea, soybean meal, or corn gluten meal 60 on the microbial synthesis efficiency, in situ dry matter (DM) and neutral detergent fiber (NDF) degradability. The treatments were: sugar cane, sugar cane with urea, soybean meal or corn gluten meal 60. Eight rumen and duodenum cannulated steers were used and arranged according to two 4 × 4 Latin Squares. The pH and N-NH3 were determined in the ruminal fluid before and 2, 4, 6 and 8 hours after feeding. The duodenal flow was estimated by indigestible acid detergent fiber. The microbial efficiency was determined by purine. RDN did not affect the DM and the highest effective degradability was observed in sugar cane supplemented with soybean meal in the NDF degradability. The pH, N-NH3 values were appropriate to the microbial synthesis in all the evaluated diets. The RDN deficiency did not affect the microbial protein synthesis and the dynamics of the liquid phase.FAPES

USE OF VIRGINIAMYCIN AND SALINOMYCIN IN THE DIET OF BEEF CATTLE REARED UNDER GRAZING DURING THE RAINY SEASON: PERFORMANCE AND RUMINAL METABOLISM

The rumen is the most studied organ with regard to the symbiotic interaction between host and microbiota in the digestive tract of ruminants. Thus, this study aimed at evaluating the effects of including virginiamycin and salinomycin to the supplement for cattle fed tropical grass diet during the rainy season. Three treatments were set: control - mineral supplement COMIGO - Cria 61-F2 (MS); virginiamycin - MS + virginiamycin (Phigrow (r)) 100 mg/animal/day; salinomycin - MS + salinomycin (Posistac(r)) 108 mg/animal/day for the experiment 1 (performance) and experiment 2 (ruminal metabolism). The control showed higher Mineral supplement intake (MSI) (P 0.05) and better financial efficiency. Biometric measurements showed no differences (P> 0.05), suggesting a change in the ADG composition. There was no difference (P> 0.05) for dry matter digestibility (DMDIS), acid detergent fiber digestibility (ADFDIS), ruminal pH and ammoniacal-N. The virginiamycin had the highest effective neutral detergent fiber (NDF) degradability (P> 0.05) in the passage rates of 2 and 5%; the degradability rates were similar to control treatement and higher than that of salinomycin at the rate of 8%/hour. The virginiamycin or salinomycin can be conveyed to the MS, but do not promote significant effects on ruminal pH, ammoniacal-N, DMDIS and ADFDIS; but virginiamycin promoted greater effective degradability of NDF. Keywords: ammoniacal-N; antimicrobials; degradability; growth; ruminal pH

QUALIDADE DA CARCAÇA E DA CARNE DE NOVILHOS ABATIDOS COM PESOS SIMILARES, TERMINADOS EM DIFERENTES SISTEMAS DE ALIMENTAÇÃO

O objetivo deste trabalho foi estudar as características qualitativas da carcaça e da carne de novilhos Aberdeen Angus terminados em confinamento, com canade-açúcar + concentrado, ou em pastagem cultivada de azevém (Lolium multiflorum) + sal comum como suplemento mineral. Abateram-se os novilhos aos 24 meses de idade com pesos similares de 394 e 396 kg, respectivamente. Alimentaram-se os animais confinados com dieta contendo, na matéria seca, 72,3% de cana-de-açúcar e 27,7% de concentrado. Os novilhos apresentaram no início da terminação peso médio de 320 kg e idade média de vinte meses. Não houve diferença nas percentagens de músculo e de osso. A percentagem de gordura foi similar, sendo de 22,8% e 20,7%, respectivamente, para animais terminados em pastagem e confinamento. A suculência, o sabor, a força de cisalhamento e a quebra no descongelamento mostraram-se maiores nos animais terminados em pastagem cultivada, sendo, respectivamente, 6,93 pontos, 6,60 pontos, 9,23 kgf e 8,28%, contra 5,93 pontos, 5,77 pontos, 7,27 kgf e 5,27%, na mesma ordem, para novilhos alimentados em confinamento. Contudo, outras características qualitativas da carne como cor, textura, marmoreio, maciez e quebra na cocção foram similares entre os tratamentos. PALAVRAS-CHAVE: Aberdeen Angus, cana-de-açúcar, confinamento, pastagem hibernal

SUBSTITUIÇÃO DO MILHO TRITURADO POR CASCA DE SOJA EM DIETAS PARA VACAS MESTIÇAS EM LACTAÇÃO

Objetivou-se avaliar a produção e composição do leite quando a casca de soja foi utilizada para substituir o milho triturado na dieta de doze vacas mestiças em lactação, distribuídas em quatro quadrados latinos 3x3. Adicionou-se a casca de soja dieta (21%, 30,1% e 39,3% do total da matéria seca) para reduzir progressivamente a porcentagem de milho triturado (24%, 15% e 5,8% do total da matéria seca). Não houve diferenças (P>0,05) para a produção de leite sem e com correção para 3,5% de gordura, teores de proteína (3,26 g/100 g) e de lactose no leite (4,67 g/100 g). Já os teores de gordura e de sólidos totais no leite aumentaram linearmente com o aumento da quantidade de casca de soja adicionada na dieta (

Digestibility and feeding behavior of cattle fed soybean hulls to replace corn in high concentrate diets

The objective of this study was to evaluate the replacement of 0, 25, 50, 75 and 100% of ground corn (GC) with pelleted soybean hulls (SH) in the concentrate portion of cattle diets. The evaluation was conducted using five 13-month-old Nellore steers cannulated in the rumen, with a mean body weight of 265.00 + 11.60 kg. The steers received a diet composed of 90% concentrate and 10% sugarcane bagasse as the only source of roughage. The statistical design used was a 5x5 Latin square. There was no effect (p > 0.05) of replacement levels or interaction (p > 0.05) between replacement levels and sampling time on ruminal pH, which ranged from 5.8 to 6.0. The apparent digestibility of DM, CP, EE, CHOT and CHONF were not influenced (p > 0.05) by the replacement levels, showing mean values of 67.88 + 2.02; 67.43 + 2.89; 68.29 + 4.11; 70.54 + 1.68 and 80.21 + 1.85%, respectively. The NDF digestibility increased linearly (p 0.05) of replacement levels on time spent feeding (F) and total idle time (TI), with mean values of 10.51 and 4.61% of the day, respectively. However there was a quadratic effect (p < 0.05) of soybean hull inclusion on the time spent ruminating. It was concluded that although the replacement of corn with soybean hull does not improve the ruminal pH of steers fed diets with a high proportion of concentrate, pelleted soybean hulls improve the digestibility of the fibrous fraction of the diet and increase the time spent ruminating, indicating that this ingredient can be included in high-concentrate diets to improve economic efficiency

Blood parameters as a possible indicator of feed efficiency in Nellore bulls

The objective of this study was to investigate the relationships between energy, protein, enzymatic metabolism, and residual feed intake (RFI) in purebred Nellore bulls. A total of 120 Nellore bulls, individually housed, underwent performance trials while being fed a high-concentrate diet. The study utilized data from the 10 most efficient, least efficient, and moderately efficient animals. Blood samples were collected via venipuncture for a complete blood count, and serum was analyzed for albumin, total protein, urea, creatinine, glucose, cholesterol, gamma GT, AST, and alkaline phosphatase. The data were subjected to a completely randomized design with three treatments and 10 replicates, and treatment means were compared using the Tukey test. Pearson's linear correlation analysis was performed. The most efficient animals demonstrated a 27.62% reduction in feed intake compared to the least efficient ones. No significant differences were observed in the serum biochemistry between different RFI classes. Inefficient animals exhibited elevated mean corpuscular hemoglobin (MCH), a red blood cell index, which correlated with RFI, gain-to-feed ratio, and dry matter intake (r = 0.46, 0.42, and -0.42, respectively). Hemoglobin concentration showed correlations with RFI and gain-to-feed ratio (r = 0.36, -0.41, respectively). These findings suggest potential variations in oxygen-carrying capacity. Red blood cell parameters could serve as biomarkers for identifying inefficient animals

Total replacement of soybean meal by urea or starea in high grain diets for beef cattle

O objetivo deste trabalho foi avaliar a substituição do farelo de soja por uréia ou amiréia no desempenho de bovinos de corte em crescimento. Foram utilizados oitenta e um machos não castrados das raças Nelore (27), Canchim (27) e Holandesa (27), com peso médio inicial de 250 kg e idade média de 15 meses. O delineamento experimental foi o de blocos ao acaso com três tratamentos, constituídos de três animais por baia e nove baias por tratamento. Os blocos foram arranjados segundo o peso inicial e raça. Os tratamentos foram: 1) farelo de soja (FS); 2) uréia e 3) amiréia (A-150S) em dietas isoprotéicas (13,0%) utilizando o bagaço de cana in natura (BIN) como única fonte de volumoso (20% da MS). O consumo de matéria seca (MS) foi 6,56, 7,18 e 6,97 kg/dia; o ganho de peso vivo foi 0,889, 1,114 e 1,088 kg/dia e a conversão alimentar de 7,3, 6,5 e 6,7 kg MS/kg de ganho nos tratamentos farelo de soja, uréia e amiréia, respectivamente. O tratamento FS apresentou menor consumo e ganho de peso e também pior conversão alimentar (P 0,05) entre si.The objective of this work was to evaluate the effects of replacing soybean meal by urea or starea on feedlot cattle performance. Eighty-one yearling intact males (27 Nellore, 27 Canchim and 27 Holstein) were used, with initial body weight of 250 kg. Animals were assigned to a completely random block design according to initial weight and breed. There were nine pen/treatment with three animals/pen. Experimental treatments were: 1) soybean meal, 2) urea and 3) starea. Diets contained 13% CP and were composed of 80% concentrate and 20% raw sugarcane bagasse. DMI was 6.56, 7.18 and 6.97 kg/day, average daily gain was 0.889, 1.114 and 1.088 kg/day and feed conversion was 7.3, 6.5 and 6.7 kg DM/kg gain for soybean meal, urea and starea, respectively. Soybean meal reduced (P 0.05) between urea and starea treatments