Increasing Replacement Level Research Articles

Effect of Potato By-products Based Silage on Rumen Fermentation, Methane Production and Nitrogen Utilization in Holstein Steers

The effect of substituting potato by-products based silage (PBS) for concentrates on ruminal fermentation, methane production and nitrogen utilization in Holstein steers was evaluated. Three growing Holstein steers (490±19 kg, initial body weight) were used in a 3×3 Latin square experiment with three experimental diets in which PBS was included at (1) 0, (2) 19 and (3) 27%, on a dry matter basis, replacing concentrates and wheat bran. Increasing replacement levels of PBS slightly increased dry matter (DM), organic matter (OM), NDF and ADF intakes by the steers (p<0.05). Inclusion of PBS at 19% increased crude protein (CP) digestibility of the experimental diets compared with the control (p<0.05). Substitution with PBS increased ADF digestibility and nitrogen retention (p<0.05), but did not affect energy retention. Energy loss as methane ranged between 5.0 and 6.1% of the total gross energy intake. There were no significant differences in carbon dioxide and methane production among all PBS levels, while daily methane production numerically increased with PBS inclusion. Substituting PBS for concentrates did not significantly affect ruminal pH and ammonia N concentration. Total VFA concentration, VFA molar proportions and blood metabolites were also unaffected by PBS replacement. These results suggest that substitution of PBS up to 27% of diet dry matter did not significantly increase methane production and was equal or

Substituting sunflower seed-cake with Moringa oleifera leaves as a supplemental goat feed in Tanzania

Scarcity of animal feed resources, particularly during the dry season, is a major constraint to livestock production in the tropics. Animal feed supplement such as sunflower seed cake (SSC) are too expensive for most farmers. Therefore, alternative resources need to be investigated. Moringa oleifera Lam (Moringaceae) is a multipurpose tree, the leaves of which are used as animal feed in many places; but its potential as an animal feed supplement has not been documented. The effect of substituting SSC with different levels of M. oleifera (MOOL) on dry matter intake (DMI), dry matter digestibility (DMD) and growth performance of small, East African goats fed low-quality Chloris gayana hay was investigated in Morogoro-Tanzania. The supplementary treatments were different levels of MOOL, so that the proportions of MOOL to SSC were 0:100, 25:75, 75:25 and 100:0. All animals were fed with low-quality Chloris gayana hay as a basal ration. After a preliminary feeding period of 14 days, DMI data were collected for 21 days. Restricted feeding, and collection of urine and faecal samples for analysis were carried within 7 days of the preliminary period and 14 days of data collection. A significantly higher DMI and metabolisable energy intake (MEI) were observed at 75 and 100% MOOL supplementary levels. Increased replacement levels of SSC with MOOL increased the digestibility of DM (dry matter) and NDF (neutral detergent fibre). Goats fed 25 MOOL (T2) had significantly higher nitrogen retention than goats in the other treatments. The treatments were not different in terms of effect on the growth rates of the goats. The results suggest that MOOL could be used as a substitute for SSC, the conventional supplemental feed.

Substituição da Proteína do Farelo de Soja pela Proteína do Farelo de Canola em Rações para Alevinos de Curimbatá (Prochilodus lineatus V.)

Objetivando verificar a influência da substituição da proteína do farelo de soja (FS) pela proteína do farelo de canola (FC), em rações para alevinos de curimbatá, foram utilizados 120 animais com peso médio de 1,88 ± 0,82 g e comprimento total médio de 5,40 ± 0,99 cm, distribuídos em um delineamento inteiramente casualizado com seis tratamentos e quatro repetições em aquários de vidro (50 L), com cinco alevinos por unidade experimental. As rações foram formuladas para serem isoprotéicas (26,00%), isocálcicas (0,90%) e isofosfóricas (0,70%), com níveis crescentes de substituição da proteína do FS pela do FC (0,00; 20,00; 40,00; 60,00; 80,00 e 100,00%), o que correspondeu a 0,00; 8,03; 16,10; 24,10; 32,15 e 43,12% de inclusão do FC nas rações e fornecidas por um período de 30 dias. Os parâmetros físico-químicos da água foram medidos a cada sete dias. Observou-se redução linear do ganho de peso e da taxa de eficiência protéica e aumento linear da taxa de conversão alimentar, com aumento da inclusão do FC nas rações. A taxa de sobrevivência e o custo de ração/kg ganho não foram afetados com o uso do FC nas rações. Os valores da temperatura da água, do pH e da condutividade elétrica permaneceram dentro dos níveis adequados. Concluiu-se que o aumento dos níveis de inclusão da proteína do farelo de canola nas rações para alevinos de curimbatá acarretou redução no desempenho dos mesmos.

Workability of concrete incorporating pulverized fuel ash and metakaolin

Workability of concrete incorporating combinations of pulverized fuel ash (PFA) and metakaolin (MK) as partial replacements for Portland cement (PC) has been investigated. The aim of the research work is to explore the potential of using PFA and MK as blends with PC in terms of the flow properties of the resulting concrete. Ninety mixtures containing 0, 10, 20, 30 and 40% total replacement of cement with combinations of metakaolin (0–15%) and PFA (0–40%) for concretes with water to binder ratios of 0·4, 0·5 and 0·6 were prepared. The workability of the concrete was measured by the slump, compacting factor and Vebe time tests. Substantial reductions in the workability were obtained when the mixtures contained MK only, with greater reductions being experienced as the MK replacement level increased. In contrast, the mixtures with PFA showed considerable improvement in workability with increase in replacement level. It was found that, for concretes containing blends of PC, PFA and MK, the loss in workability due to the presence of MK can be compensated for by the incorporation of PFA. However, at low cement replacement levels, improvement in workability by the PFA can be achieved only if a superplasticizer is used. The degree of restoration of workability provided by PFA is influenced by the level of cement replacement, MK/PFA ratio and water to binder (w/b) ratio. In particular at low w/b ratio (= 0·4), where superplasticizer is used, there is a critical MKIPFA ratio (∼0·4) above which workability decreases and below which workability increases with increasing replacement level. In general, the incorporation of PFA not only compensates for the loss of workability resulting from the presence of MK but also provides economic benefits.

Effect of Various Animal and Vegetable Protein Materials on Replacing the Beef Component in a Meat Emulsion System

Up to 80% of the beef component in a meat emulsion system was replaced by various animal and vegetable protein materials. The basic emulsion was composed of lean beef, pork backfat, ice and salt and contained 60% water, 25% fat and 3% salt in all cases. The characteristics of the emulsion examined included cook stability and textural properties of the cooked product. At high replacement levels, increased yields were obtained with gluten, soy isolate and egg white and reduced yields with tripe, cooked beef and a textured soy product. Losses of volatiles were similar for all replacement levels and replacement materials. Yields were closely related to drip losses; these losses were largely accounted for by losses of the non-lipid fraction. Textural characteristics differing from the control were observed at the 40% replacement levels. Firmness, rupture force and resilience decreased with increased replacement levels with these differences being most noticeable with tripe, gluten and soy isolate. Egg white displayed little detrimental effect on texture through the 0 to 60% replacement range. The form (powdered or texturized) of the replacement protein material (textured soy protein) had no effect on yield results; the texturized form had a definite positive effect on the texture of the cooked meat emulsion.

Sound transmission of sawdust concrete : D. L. Rich and C. R. Brown. ( Phys. Rev., Feb., 1923.)

This paper investigates the use of sawdust as fine aggregate and its influence on the properties of hardened concrete, and examines the correlation between sawdust content and hydration days. In this study, untreated wood sawdust from a wood factory in Bangladesh is added to concrete mixtures. Concrete mixtures prepared by replacing fine aggregates with sawdust in the ratio of 10%–60% are evaluated for compressive, tensile, and flexural strength along with sulphate resistance for four different hydration periods. In addition, the microstructure of sawdust concrete is studied using scanning electron microscopic images. The micrographs show a wider formation of cracks, openings, and interface gaps in the cement matrix with the addition of sawdust. However, after sulphate immersion, the gaps and cracks are found to contract due to the ettringite filler effect. The addition of sawdust is found to reduce the workability and to have an adverse effect with increasing replacement levels. Similarly, reduced density of the hardened concrete is observed in the case of the sawdust concrete mixtures. Experimental results and cost comparison reveal that ten percent sawdust substitution is found to be optimal and low-cost replacement to natural fine aggregates with respect to the hardened properties, as it yields better performance in comparison with the other replacement ratios. Also, sulphate immersion for a period of 28 days is found to improve the compressive strength, even for mixtures with higher sawdust content. Moreover, a model is developed to predict the compressive and tensile strength of sawdust concrete using regression analysis.

Heat transmission

This paper reviews the effect of incorporating recycled aggregates, sourced from construction and demolition waste, on the carbonation behaviour of concrete. It identifies various influencing aspects related to the use of recycled aggregates, such as replacement level, size and origin, as well as the influence of curing conditions, use of chemical admixtures and additions, on carbonation over a long period of time. A statistical analysis on the effect of introducing increasing amounts of recycled aggregates on the carbonation depth and coefficient of accelerated carbonation is presented. This paper also presents the use of existing methodologies to estimate the required accelerated carbonation resistance of a reinforced recycled aggregate concrete exposed to natural carbonation conditions with the use of accelerated carbonation tests. Results show clear increasing carbonation depths with increasing replacement levels when recycled aggregate concrete mixes are made with a similar mix design to that of the control natural aggregate concrete. The relationship between the compressive strength and coefficients of accelerated carbonation is similar between the control concrete and the recycled aggregate concrete mixes.