Replacement of dicalcium phosphate by rock phosphate in cattle diets: nutrients digestibility, plasma parameters, ruminal fermentation and microbial synthesis efficiency

Este estudo foi conduzido para avaliar os efeitos da substituição do fosfato bicálcico pelo fosfato de rocha na dieta de bovinos em crescimento. Foram determinados a digestibilidade aparente das dietas, a absorção aparente do fósforo, cálcio e flúor, o pH ruminal, a concentração de amônia ruminal, a eficiência microbiana e o fósforo no plasma utilizando-se cinco bovinos da raça Holandesa Preto-e-Branco, fistulados, pesando entre 275 e 283 kg. O delineamento estatístico foi um quadrado latino 5 × 5 e as dietas consistiram de 0, 25, 50, 75 e 100% de substituição do fosfato bicálcico pelo fosfato de rocha no suplemento mineral. A adição de fosfato de rocha nas dietas ocasionou aumento linear na ingestão, no fluxo omasal, no fluxo fecal e no desaparecimento total do flúor. As dietas não diferiram quanto à absorção aparente do cálcio, assim como em relação à ingestão, excreção, digestão e digestibilidades aparentes parcial e total da matéria seca, matéria orgânica, proteína bruta, fibra em detergente neutro e carboidratos não-fibrosos. O fósforo no plasma não foi influenciado pelos tratamentos e a média foi de 5,93 mg/dL. Não houve diferença para o pH ruminal e concentração de amônia ruminal. A substituição do fosfato bicálcico não afetou a síntese microbiana aparente e verdadeira de proteína. A total substituição do fosfato bicálcico pelo fosfato de rocha em suplementos minerais em bovinos em crescimento não afetou o ambiente ruminal e a síntese de proteína no rúmen. Assim, a substituição do fosfato bicálcico em dietas para bovinos em crescimento diminui a absorção de fósforo e deveria ser vista com cuidado dependendo dos requerimentos.

Interaction Between Roughages and Corn Milling Byproducts in Finishing Cattle Diets

During ethanol production, starch is the primary nutrient fermented and the remaining byproducts are excellent sources of fiber and protein. In addition, inclusion of byproducts in finishing diets may reduce the incidence of acidosis. As a result, roughage level and quality could potentially be reduced in finishing diets containing byproducts. Three experiments were conducted to examine the effects of roughage and wet corn gluten feed (WCGF) in finishing cattle diets containing corn distillers grains plus solubles. Cattle fed finishing diets containing wet distillers grains plus solubles (WDGS) with no roughage had decreased DMI and ADG compared to cattle fed roughage. Within roughage level, ADG was similar for cattle fed alfalfa hay, corn silage or corn stalks when included on an equal NDF basis. Apparent total tract digestibility of OM, NDF, and CP linearly decreased and ruminal pH variables increased linearly due to increasing roughage levels. Roughage sources can be exchanged on an equal NDF basis in beef finishing diets containing 30% WDGS (DM basis). In finishing diets containing modified distillers grains plus solubles (MDGS), DMI linearly increased due to increasing roughage levels but ADG responded quadratically and was lowest for cattle fed diets without roughage. There was also a quadratic response for DMI and ADG due to WCGF inclusion level. Gain:feed decreased linearly with increasing roughage and WCGF inclusion levels. Feeding 15% WCGF resulted in similar cattle performance and carcass traits to cattle fed no WCGF in diets containing 30% MDGS, but cattle fed diets with 60% total byproduct inclusion made up of 30% WCGF and 30% MDGS had reduced performance (DM basis). Additionally, reducing corn silage inclusion level to 7.5% resulted in similar finishing cattle performance and carcass traits to cattle fed 15% corn silage in diets containing 30% MDGS with or without inclusion of WCGF. Elimination of roughage in diets containing either WDGS or MDGS resulted in negative impacts on finishing cattle performance, ruminal metabolism, and carcass traits.

Substitution of crude cell wall for neutral detergent fibre in the equations of the Cornell Net Carbohydrate and Protein System that predict carbohydrate fractions: application to sunflower (Helianthus annulus L.)

Prediction of carbohydrate fractions using equations from the Cornell Net Carbohydrate and Protein System (CNCPS) is a valuable tool to assess the nutritional value of forages. In this paper these carbohydrate fractions were predicted using data from three sunflower (Helianthus annuus L.) cultivars, fresh or as silage. The CNCPS equations for fractions B(2) and C include measurement of ash and protein-free neutral detergent fibre (NDF) as one of their components. However, NDF lacks pectin and other non-starch polysaccharides that are found in the cell wall (CW) matrix, so this work compared the use of a crude CW preparation instead of NDF in the CNCPS equations. There were no differences in the estimates of fractions B, and C when CW replaced NDF; however there were differences in fractions A and B2. Some of the CNCPS equations could be simplified when using CW instead of NDF Notably, lignin could be expressed as a proportion of DM, rather than on the basis of ash and protein-free NDF, when predicting CNCPS fraction C. The CNCPS fraction B(1) (starch + pectin) values were lower than pectin determined through wet chemistty. This finding, along with the results obtained by the substitution of CW for NDF in the CNCPS equations, suggests that pectin was not part of fraction B(1) but present in fraction A. We suggest that pectin and other non-starch polysaccharides that are dissolved by the neutral detergent solution be allocated to a specific fraction (B2) and that another fraction (B(3)) be adopted for the digestible cell wall carbohydrates.

Evaluation of Condensed Porcine Solubles as a Source of Supplemental Nitrogen in Corn-Based Finishing Diets for Yearling Steers

A feeding trial was conducted with 860-lb yearling steers fed 121 days to evaluate Condensed Porcine Solubles (Porcine Solubles) as a source of supplemental nitrogen for finishing cattle. Diets containing 5% soybean meal, 1.46% urea, and 2% or 4% Porcine Solubles were compared. When first offered, cattle did not want to consume feed containing the Porcine Solubles. Following adaptation, feed containing up to 4% Porcine Solubles was readily consumed. During the first 56 days, steers fed soybean meal gained faster and were more efficient than steers fed urea or Porcine Solubles. At the end of the trial there were no differences among the nitrogen supplements in feed intake, gain, or feed conversion. There were no significant differences in carcass weight or measures of carcass quality.

Dairy cattle-slurry treatment technologies: towards an integrating approach of crop production, animal feeding and environmental impacts

Dairy cattle farms have a well-known environmental impact that affects all ecological compartments: air, soil, water and biosphere [1]. Dairy cattle farming are a significant source of anthropogenic gases from enteric fermentation, manure storage and land application, mainly ammonia (NH3), nitric oxide (NO), nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4). The emission of such gases represents not only an environmental problem but also leads to energy and nitrogen (N) losses in ruminant production systems [2-5]. Several efforts are required on the development of new technologies and strategies that mitigate gaseous emissions, N losses and improve the efficiency of the energy and N cycles [6, 7]. In the Northwest of Portugal, dairy cattle production has a major impact on the economy, with strong repercussions at national scale. Therefore, our Ph.D. thesis project aims to: a) Study natural supplements as additives in the dairy cattle diet towards a decrease in GHG emissions from feeding operations; b) Compare commercial dairy cattle diets with and without additives on gaseous emissions from manure deposited in a simulated concrete floor; c) Assess the concentrations and emissions of NH3 and greenhouse gases from commercial dairy cattle facilities; d) Evaluate the effects of different additives on lowering gaseous emissions from dairy cattle excreta, using a laboratory system simulating a dairy house concrete floor.

Desempenho e características da carcaça de bovinos alimentados com dietas com caroço de algodão

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Desempenho e características da carcaça de bovinos nelores terminados em confinamento com dietas a base de caroço de algodão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização de glicerina, subproduto do biodiesel, na alimentação de bovinos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Biodigestão anaeróbia dos dejetos de suínos e bovinos e utilização do biofertilizante no capim-piatã

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Consumo e digestibilidade de dietas contendo fontes energéticas associadas ao farelo de girassol ou ureia em novilhos confinados

Objetivou-se avaliar o consumo e a digestibilidade total e parcial de dietas utilizando milho, casca de soja e polpa cítrica associados ao farelo de girassol ou ureia em novilhos confinados. Foram utilizados quatro novilhos ½ Aberdeen Angus vs. ½ Nelore, providos de cânulas no rúmen e duodeno, com 18 meses de idade e 360 kg de peso médio inicial. As dietas foram constituídas por duas fontes energéticas (milho grão e polpa cítrica) associadas a duas fontes nitrogenadas (ureia e farelo de girassol), totalizando quatro tratamentos, numa proporção volumoso:concentrado de 40:60. O delineamento utilizado foi o quadrado latino com quatro tratamentos e quatro períodos de 21 dias cada. O consumo médio diário de matéria seca foi influenciado (p < 0,05) entre as dietas, e o maior valor foi atribuído à dieta milho e farelo de girassol. A digestibilidade aparente de todos os componentes, exceto da proteína bruta, foi maior (p < 0,05) para as dietas com polpa cítrica. Não houve efeito (p > 0,05) entre as dietas para as digestibilidades ruminal e intestinal. A utilização de coprodutos na alimentação animal não prejudicou a digestibilidade das dietas, sendo indicados como ingredientes de elevado potencial de utilização em dietas para bovinos de corte.

Effects of Initial Body Condition, Frame Size and Concentration of Dietary Energy on Performance of Finishing Steers

Steers were sorted into four groups based on hip height and fat cover at the start of the finishing period. Each group of sorted steers was fed a diet containing 0.59 or 0.64 Mcal NEg per pound of diet. Steers with less initial fat cover (.08 in.) gained slightly faster, consumed less feed, and therefore tended to be more efficient than steers with greater finish (.16 in.). Steers fed the lower-energy diet consumed more feed, gained similarly, and were less efficient than steers fed the higher-energy diet. The NRC computer model to evaluate beef cattle diets underpredicted performance of cattle in this experiment, but accurately predicted the differences in gain and feed efficiency observed between the leaner and fatter steers and between the two diets. In this study, the shorter steers (49.4 vs 52.2 in. initial height at the hip) gained faster with slightly greater feed intake and the same feed conversion.

Aditivos (ionóforo e não ionóforo), processamento de grãos de milho e concentrações de fibra insolúvel em detergente neutro (FDN) de silagem de milho em dietas para bovinos em terminação

Foram conduzidos dois experimentos com o intuito de se avaliar o desempenho, características de carcaça e parâmetros ruminais de bovinos Nelore recebendo dietas contendo grãos de milho flint processados de diferentes formas em associação a diferentes aditivos e níveis de FDN de silagem de milho (FDNf). No Experimento 1, 239 tourinhos (PCI=350±26,79kg) foram alojados em 40 baias de acordo com o peso corporal inicial e receberam dietas contendo dois tipos de processamento dos grãos de milho (moagem fina e floculação) e diferentes aditivos (monensina sódica; 25 ppm e formulação A062 a base de virginiamicina; produto teste, não comercial, fornecido pela Ourofino Saúde Animal; nas dosagens de 17 e 25 ppm), totalizando 8 tratamentos. Os dados foram analisados pelo PROC MIXED do SAS. A floculação aumentou o peso final, o ganho de peso diário, a eficiência alimentar, o peso da carcaça quente e tendeu a aumentar o rendimento de carcaça em comparação a moagem fina. Houve tendência de interação entre processamento e fornecimento de aditivos para a ingestão de matéria seca e ganho de peso diário. A floculação reduziu o teor de amido fecal, aumentou a digestibilidade do amido no trato total, aumentou os valores de energia liquida para manutenção e ganho da dieta e o numero médio de papilas ruminais. Os aditivos aumentaram a altura, largura e área das papilas e reduziram a espessura de faixa de queratina em relação ao tratamento controle. Houve tendência das formulações a base de virginiamicina aumentarem o peso da carcaça quente dos animais em comparação com a monensina sódica, mas não em relação ao tratamento controle sem aditivo. A floculação foi mais efetiva para aumentar a digestiblidade do amido no trato total, o valor energético do milho e o desempenho dos bovinos enquanto que os aditivos não foram efetivos para aumentar o valor energético das dietas e a eficiência alimentar dos animais. No Experimento 2, 237 tourinhos (PCI=350±28,49kg) foram alojados em 32 baias de acordo com o peso corporal inicial e receberam dietas contendo dois tipos de processamento (moagem grosseira e floculação) e diferentes níveis de FDNf (4; 7; 10 e 13% MS), totalizando 8 tratamentos. Os dados foram analisados pelo PROC MIXED do SAS. A floculação tendeu a aumentar a eficiência alimentar, o peso da carcaça quente e a espessura de gordura subcutânea, reduziu o teor de amido fecal, aumentou a digestibilidade do amido no trato total como também aumentou os valores de energia liquida para manutenção e para ganho das dietas. Os níveis de FDNf afetaram ingestão de matéria seca e o peso da carcaça quente independente do método de processamento. Houve tendência de aumento linear no GPD e tendência de redução quadrática na eficiência alimentar com inclusão crescente de FDNf. A inclusão de silagem de milho em dietas com alto teor de milho flint reduziu a eficiência alimentar dos animais, mas aumentou o peso da carcaça quente. A floculação aumentou o valor energético do cereal para tourinhos Nelore em dietas com alto teor de energia.

Productive performance, nutrient digestion and metabolism of Holstein (Bos taurus) and Nellore (Bos taurus indicus) cattle and Mediterranean Buffaloes (Bubalis bubalis) fed with corn-silage based diets

The objective of this study was to evaluate the productive performance, nutrients digestion and metabolism of three different genetic groups fed with the same diet based on corn silage. 30 heifers in growth were used of three groups of cattle, the following: Nellore (Bos taurus indicus) (n = 10), Holstein (Bos taurus taurus) (n = 10), and Mediterranean buffaloes (Bubalis bubalis) (n = 10). The animals were fed in groups and received the same experimental diet composed of corn silage and concentrate for growing heifers. In the evaluation of animals the performance, consumption and total apparent digestibility of dry matter and nutrients with the aid of internal markers (chromic oxide) and external (iADF), rumen fermentation, excretion of purine derivatives, nitrogen balance and blood metabolites were measured. No differences were observed in animal performance. There were differences in nutrient intake and apparent digestibility of dry matter and nutrients in different groups of cattle. The concentration of ammonia nitrogen (NH3-N) and short chain fatty acids (SCFA) in the rumen were higher and lower, respectively, for the group of buffaloes in relation to other experimental groups evaluated. When considering the excretion of total purine derivatives, buffaloes showed the lowest value compared to other genetic groups evaluated; about 61.76% of the total genetic group Nellore and 57.62% of the total genetic group Holstein with an average of 33.67 mmol/day. For the buffaloes, the excretion of xanthine and hypoxanthine observed was of 5.11% of total purine derivatives. There was a better nitrogen balance (g/day) for groups of Holstein heifers and Nellore in relation to the group of buffalo heifers. There were differences in the concentrations of urea and urea nitrogen in serum and liver enzymes where the buffaloes had higher values in relation at the bovines. There is a great metabolic diversity among the experimental groups evaluated and it was more exacerbated among buffaloes and bovines, when submitted to the same diet and same management conditions. (C) 2011 Elsevier B.V. All rights reserved.

Intake, live-weight gain and carcass characteristics of beef cattle given diets based on forage maize silage harvested at different stages of maturity

Advancing maturity of forage maize is associated with increases in the proportion of dry matter (DM) and starch, and decreases in the proportions of structural carbohydrates in the ensiled crop. This experiment investigated the effects of three maize silages of 291 (low), 339 (medium) and 393 (high) g DM per kg fresh weight on the performance of 48 Simmental. Holstein-Friesian cattle. Equal numbers of steers (mean start weight = 503 (s.d. 31.3) kg) and heifers (mean start weight = 378 (s.d. 11.2) kg) were offered individually isonitrogenous diets composed of the three silages plus a protein supplement with minerals once daily until slaughter at the target live weight of 575 and 475 kg for steers and heifers, respectively. Intake was reduced on the low diet (P < 0.01) compared with the other two treatments. Dietary starch intake increased by a total of 1 kg/day between low and medium diets but by only 0.2 kg/day between medium and high diets. Unlike starch intake, total neutral-detergent fibre intake showed no significant difference (P > 0.05) between diets. There were no differences in live-weight gain between treatments but differences (P < 0.05) in food conversion efficiency indicated relative gains of 115, 100 and 102 g gain per kg DM intake for diets low, medium and high, respectively. There were no differences between diets in carcass weights, fat score and overall conformation.

Comparison of energy evaluation systems and a mechanistic model for milk production by dairy cattle offered fresh grass-based diets

Grass-based diets are of increasing social-economic importance in dairy cattle farming, but their low supply of glucogenic nutrients may limit the production of milk. Current evaluation systems that assess the energy supply and requirements are based on metabolisable energy (ME) or net energy (NE). These systems do not consider the characteristics of the energy delivering nutrients. In contrast, mechanistic models take into account the site of digestion, the type of nutrient absorbed and the type of nutrient required for production of milk constituents, and may therefore give a better prediction of supply and requirement of nutrients. The objective of the present study is to compare the ability of three energy evaluation systems, viz. the Dutch NE system, the agricultural and food research council (AFRC) ME system, and the feed into milk (FIM) ME system, and of a mechanistic model based on Dijkstra et al. [Simulation of digestion in cattle fed sugar cane: prediction of nutrient supply for milk production with locally available supplements. J. Agric. Sci., Cambridge 127, 247-60] and Mills et al. [A mechanistic model of whole-tract digestion and methanogenesis in the lactating dairy cow: model development, evaluation and application. J. Anim. Sci. 79, 1584-97] to predict the feed value of grass-based diets for milk production. The dataset for evaluation consists of 41 treatments of grass-based diets (at least 0.75 g ryegrass/g diet on DM basis). For each model, the predicted energy or nutrient supply, based on observed intake, was compared with predicted requirement based on observed performance. Assessment of the error of energy or nutrient supply relative to requirement is made by calculation of mean square prediction error (MSPE) and by concordance correlation coefficient (CCC). All energy evaluation systems predicted energy requirement to be lower (6-11%) than energy supply. The root MSPE (expressed as a proportion of the supply) was lowest for the mechanistic model (0.061), followed by the Dutch NE system (0.082), FIM ME system (0.097) and AFRCME system(0.118). For the energy evaluation systems, the error due to overall bias of prediction dominated the MSPE, whereas for the mechanistic model, proportionally 0.76 of MSPE was due to random variation. CCC analysis confirmed the higher accuracy and precision of the mechanistic model compared with energy evaluation systems. The error of prediction was positively related to grass protein content for the Dutch NE system, and was also positively related to grass DMI level for all models. In conclusion, current energy evaluation systems overestimate energy supply relative to energy requirement on grass-based diets for dairy cattle. The mechanistic model predicted glucogenic nutrients to limit performance of dairy cattle on grass-based diets, and proved to be more accurate and precise than the energy systems. The mechanistic model could be improved by allowing glucose maintenance and utilization requirements parameters to be variable. (C) 2007 Elsevier B.V. All rights reserved.