Finishing of grazing crossbred steers supplemented with detoxified castor bean meal (Ricinus communis L.) in the rainy-dry transition period.

This study evaluated levels of replacement of soybean meal by castor bean meal in the finishing crossbred steers on Brachiaria brizantha cv. Marandu pasture during the rainy-dry transition period. Forty Holstein-Zebu crossbred steers with an average initial weight of 395.93 ± 10 kg were randomly allocated to four treatment groups that were supplemented with concentrate levels of replacing (0, 290, 613, and 903 g/kg DM of the supplement; at 0.4% body weight [BW]). The experimental period was 120 days. A completely randomized experimental design was adopted; with regression analysis using the computational software package (SAS 9.2, USA). Intake and digestibility of dry matter (DM) and nutrients and animal performance were evaluated. The replacement levels did not influence (P > 0.05) the intakes of DM (kg/day), organic matter (OM, kg/day), neutral detergent fiber (NDF, kg/day and %BW), non-fibrous carbohydrates (NFC, kg/day), or total digestible nutrients (kg/day). However, the intake of crude protein (CP) and ether extract (EE, kg/day) decreased as the replacement levels were increased (P < 0.05). The digestibility of DM, OM, NDF, and EE did not change, whereas CP digestibility decreased linearly and NFC digestibility increased linearly (P < 0.05). The replacement levels did not affect (P > 0.05) final body weight, average daily gain, feed conversion, and carcass yield. Castor bean meal can replace up to 903 g/kg DM of soybean meal in the composition of the supplement without compromising the performance of steers on Marandu pasture during the rainy-dry transition period.

Detoxified castor seed meal replaces soybean meal in the supplement for Holstein-Zebu crossbred steers finished on tropical pasture during the rainy season.

The objective of this study was to examine the effect of replacing soybean meal (SBM) with detoxified castor seed meal (DCM) on the intake, digestibility, feeding behavior, and performance of pasture-finished (rainy season) steers supplemented with concentrate at 0.4% of their body weight. Forty ½ Holstein + ½ Zebu steers (initial weight: 283.3 ± 36.3 kg) were allocated to four treatments in a completely randomized experimental design. Treatments consisted of diets in which DCM replaced 0, 30, 60, and 90% of SBM in the supplement dry matter (DM). The steers were finished on an Urochloa brizantha pasture and the experiment lasted 112 days. Replacing SBM with DCM did not influence (P > 0.05) the intake or apparent digestibility of DM, crude protein, or neutral detergent insoluble fiber of the animals. Grazing time increased (P < 005), whereas the intake and rumination efficiencies of the steers did not change (P > 0.05) with the substitution. The replacement of SBM with DCM in the supplement fed to the steers also did not influence (P > 0.05) their final weight, average daily gain, or feed conversion (P > 0.05). We recommend replacing up to 90% (DM basis) of SBM with DCM in the concentrate supplement of steers grazing on Urochloa brizantha pasture during rainy season while supplemented with concentrate at 0.4% of their body weight.

Intake, digestibility, ruminal parameters, and performance in lamb fed with increasing levels of red propolis extract.

The objective of this study was to examine the effect of increasing levels of red propolis extract (RPE) on the intake, digestibility, feeding behavior, rumen parameters, metabolic parameters, and performance of feedlot lambs. Thirty-five uncastrated male Santa Inês lambs with an initial weight of 17.08 ± 2.36 kg were used in a completely randomized design with five treatments (0, 7, 14, 21, or 28 mL RPE/animal/day). The animals were confined for 68 days. Red propolis extract induced a negative quadratic response (P < 0.05) in the intakes of dry matter, organic matter, crude protein, ether extract, neutral detergent fiber, non-fibrous carbohydrates, and metabolizable energy. The apparent digestibility coefficients of dry matter, organic matter, and neutral detergent fiber, as well as the rumen concentration of NH3-N, also responded quadratically (P < 0.05) to RPE. Feeding efficiency increased linearly (P < 0.05) with the inclusion of RPE, whereas rumination efficiency was maximum (P < 0.05) at the RPE level of 16 mL/day. Red propolis extract induced a linear response (P < 0.05) in serum total protein, albumin, creatinine, and gamma-glutamyl transpeptidase. There was a quadratic effect on final body weight and average daily gain with minimum values for inclusion of RPE of 12.89 mL/day and 10.93 mL/day respectively. Feed efficiency rose linearly (P < 0.05) with the increasing concentrations of RPE in the diet. The inclusion of 21 mL RPE/day (8.5 mg total flavonoids/mL) in the diet of feedlot lambs is recommended to reduce the rumen NH3-N production and increase the animals' performance.

Feeding behavior of post-weaned crossbred steers supplemented in the dry season of the year.

The objective of this study was to evaluate the feeding behavior of grazing steers supplemented in the dry season of the year. Thirty-two castrated crossbred (½ Holstein-Zebu) steers with an average initial weight of 378 ± 7.54 kg, aged 14 months, were distributed into four treatment groups in a completely randomized design with eight replicates. The animals were managed in an area covered with a pasture of Brachiaria brizantha cv. Marandu, in a rotational grazing system. The supplement was formulated so that the animals in the different treatment groups would ingest the same amount of crude protein (CP) daily. Thus, the treatments consisted of increasing levels of supplementation, based on the animals' body weight (BW), as the protein content of the supplement was reduced. The following treatments (dry matter basis) were tested: T2, supplement at 0.2% BW, with 50% CP; T4, supplement at 0.4% BW, with 25% CP; T6, supplement at 0.6% BW, with 16.67% CP; and T8, supplement at 0.8% BW, with 12.5% CP. Forage dry matter intake decreased linearly (P < 0.05), characterizing a substitution effect. The increasing supplementation levels influenced the animals' feeding behavior, especially grazing time, total feeding time, number of grazing bouts, and number of bites per day, which showed a positive quadratic response (P < 0.05), and rumination time, number of rumination bouts, number of cuds ruminated per day, and number of chews per ruminated cud, which exhibited a negative quadratic behavior (P < 0.05). Dry matter and neutral detergent fiber (NDF) feed efficiencies and dry matter and NDF rumination efficiencies responded quadratically (P < 0.05). In conclusion, concentrate supplementation at up to 0.8% BW improves the feeding behavior of grazing steers in terms of the intake of concentrate supplement and forage as well as the feed and rumination efficiencies.

Ingestive behavior of Girolando steers supplemented on tropical pastures.

In this study, we evaluated the feeding behavior of Girolando steers on Brachiaria brizantha cultivar Marandu pastures. Twenty-two animals with an average initial weight of 209.09 ± 8.18 kg were distributed in a completely randomized design in a 3 × 2 factorial arrangement (three seasons and two nutritional plans (NP)) with 11 replicates, as follows: rainy season 1 (NP1, mineral mixture ad libitum, and NP2, nitrogen/energy supplement [2 g.kg‒1 body weight [BW]]); dry season (NP1, nitrogen/energy supplement [1 g.kg‒1 BW], and NP2, nitrogen/energy supplement [2 g.kg‒1 BW]); and rainy season 2 (NP1, mineral mixture ad libitum, and NP2, nitrogen/energy supplement ([1 g.kg‒1 BW]). Total chewing time was longer in NP1 (566.44 vs 528.33 min.day‒1 in NP2) (p < 0.05). The grazing, idle, trough, and total chewing times were affected by the interaction between nutritional plans and seasons. The period expended grazing was longer for the NP1. The idle time was affected by the nutritional plans and was lower for the NP1. Feeding at the trough was not affected by the nutritional plans. The animals of the NP2 showed the highest feed efficiencies in DM and NDF (0.91 and 0.52 vs 0.75 and 0.45 in NP1, respectively). Rainy season 2 had the highest efficiencies. The feeding behavior changes according to the supplementation level. Nutritional plan 2 in the second rainy season presented the best results.

Effects of replacing ground corn with Nopalea cochenillifera meal on the intake, performance, and economic viability of grazing steers.

The objective of this study was to evaluate the effects of replacing different levels of spineless-cactus meal instead of ground corn on supplements for crossbred steers grazing in Urochloa brizantha cv. Marandú pastures. Forty crossbred steers with an average body weight (BW) of 261 ± 7.46 kg were distributed in a completely randomized design. In supplements, the ground corn grain was substituted with 0%, 30%, 60%, and 90% spineless-cactus meal. The substitution of spineless-cactus meal instead ground corn promoted a linear decrease in the ether extract (EE; P = 0.03) and non-fibrous carbohydrates (NFC; P < 0.01) intakes. The apparent digestibility of EE was influenced (P < 0.05) showing a linear decrease. The apparent digestibility of NFC had a quadratic effect (P = 0.03). For the neutral detergent fiber corrected for ash and protein, the apparent digestibility increased linearly (P = 0.01). The average daily gain showed a quadratic effect (P < 0.01), with a maximum response estimated at 44.94% (1055.52 g/day) substitution with spineless-cactus meal for ground corn. The cost per animal per period and the cost per hectare decreased linearly (P < 0.01). The revenue, net revenue, exchange rate, and monthly revenue of the activity showed quadratic responses to the spineless-cactus meal supplements (P < 0.01), with maximum effects at 44.99%, 47.46%, 61.25%, and 57.35%, respectively. The substitution with up to 44.94% of spineless-cactus meal for ground corn provided daily gains, increased the feed conversion, and was favorable as a cost to the production system. Moreover, the profitability increased with maximum animal performance and improved use of fiber from pastures.

Proportions of concentrate and rehydrated ground grain corn silage at different storage times for better use of starch by lambs.

This study aimed to evaluate the nutritional and bioeconomic potential of rehydrated ground grain corn silage (RGGCS), at different storage times associated with proportions of concentrates for better starch utilization by lambs. Forty Dorper-Santa Inês crossbred lambs were used, with an average body weight of 24 ± 3.9 kg, and an average age of 90 days. The lambs were feedlot for 63 days in experiment design completely randomized, with eight repetitions and five experimental diets: Diet 1: 850 g/kg concentrate including dry ground corn; diet 2: 850 g/kg concentrate including RGGCS ensiled for 45 days; diet 3: 650 g/kg concentrate including RGGCS ensiled for 90 days; diet 4: 650 g/kg concentrate including RGGCS ensiled for 45 days; diet 5: 850 g/kg concentrate including RGGCS ensiled for 45 days. As roughage, silage corn whole plant. Starch intake was higher (P < 0.05) with the dry ground corn diet; however, digestibility was lower (P < 0.05) for most nutrients compared to the RGGCS diet. A smaller amount of starch in the feces of animals that received the RGGCS diet was found. A diet with 850 g/kg of concentrate, including RGGCS ensiled for 45 days, generates higher net income, increases nutrient intake, and could be an alternative during the fluctuation of corn prices.

Effect of dietary inclusion of licuri cake on intake, feeding behavior, and performance of feedlot cull cows.

Licuri cake (LC) is an interesting alternative nutritional component for high-grain diets for ruminants due to its high protein (21.6% CP), fat (12.0% EE), and fiber (62.8% NDF) contents. We investigated the effect of increasing levels of LC inclusion on the intake, digestibility, feeding behavior, performance, and carcass traits of cull cows fed high-grain diets. Forty Zebu cows with an initial weight of 318 ± 38.1 kg, at 105 months of age, were confined in collective stalls and fed (ad libitum) a diet containing 0, 50, 100, or 150 g/kg LC on a diet dry matter (DM) basis. Licuri cake inclusion induced quadratic responses (P < 0.05) in the intakes of DM (9.57 kg/day at 97.8 g/kg LC), crude protein (CP; 1.02 kg/day at 91.7 g/kg LC), and total digestible nutrients (6.68 kg/day at 75.2 g/kg LC). The digestibility of DM, CP, and non-fibrous carbohydrates decreased linearly (P < 0.05). Neutral detergent fiber (NDF) intake and rumination efficiencies increased linearly (P < 0.05) with the inclusion of LC in the diet. The inclusion of LC did not influence (P > 0.05) on daily weight gain, hot carcass weight, or back fat thickness in the carcass. Therefore, we recommend the inclusion of up to 150 g/kg LC in high-grain diets for feedlot cull cows.

Inclusion of palm kernel cake in the supplement reduces nutrient digestibility but does not interfere with the performance of steers finished on tropical pasture.

The aim of this study was to evaluate the effect of increasing inclusion levels of palm kernel cake (PKC) in the supplement of steers finished on a Urochloa brizantha cv. Marandu pasture on intake, digestibility, feeding behavior, weight gain, and carcass traits. Forty 1/2 Holstein × 1/2 Zebu crossbred steers with an average body weight of 352.80 ± 3.32 kg, at 36 months of age, were supplemented with concentrate at 0.4% of their body weight. Four treatments were formulated (supplement containing 0, 15, 30, or 45% PKC, dry matter [DM] basis) and the animals were monitored for 240 days, weighed, and slaughtered. The inclusion of PKC in the supplement did not influence the intakes of total DM, crude protein, or neutral detergent fiber, but increased (P < 0.05) ether extract intake and reduced (P < 0.05) non-fibrous carbohydrate intake. The apparent digestibility of DM, crude protein, and neutral detergent fiber decreased (P < 0.05), whereas intake and rumination efficiencies by the dietary treatments. Average daily gain, carcass weight, and backfat thickness did not change in response to the inclusion of PKC in the supplement. We recommend the inclusion of 45% palm kernel cake in the concentrate of steers supplemented at 0.4% of their body weight and finished on Urochloa brizantha cv. Marandu pasture.

Replacing sorghum with palm kernel cake in the diet decreased intake without altering crossbred cattle performance.

Palm kernel cake is a viable alternative for use in cattle feed to reduce production costs. The aim of this study was to evaluate the effects of concentrations in diet dry matter (DM) of palm kernel cake on intake and digestibility of nutrients and performance of cattle finished in a feedlot system. Forty non-castrated crossbred cattle, with an average age of 24 ± 2 months and an average weight of 331.12 ± 36.20 kg, were distributed among four treatments (control 0%, without heart of palm kernel cake in the diet; 8%, 16%, and 24% of palm kernel cake in diet DM). Variance and regression analysis were performed in function of the palm kernel cake concentrations in diet DM (P < 0.05). The dry matter intake decreased linearly (P < 0.05) as the concentrations in diet DM of palm kernel cake in the diet increased. The inclusion of palm kernel cake in the animals' diet decreased (P < 0.05) on dry matter digestibility. No effects (P > 0.05) of palm kernel cake on average daily gain or feed conversion were observed. The palm kernel cake can be included in the diet of crossbred bulls finished in confinement at concentrations in diet DM of up to 24%, as it has not influenced performance.

Nutrient intake and ingestive behavior of feedlot steers fed with licuri cake.

The objective of this study was to evaluate the effects of the inclusion of different levels of licuri cake on the consumption of dry matter and nutrients and ingestive behavior of feedlot crossbred steers. Forty-four crossbred steers with an average age of 24 months and a mean live weight of 358.19 ± 41.57 kg were used in the study. The animals were aleatorically distributed in a completely randomized design made up of four treatments, with 11 animals used per treatment: the control treatment (without the inclusion of licuri cake in the diet) and treatment with the inclusion levels of 8.5, 17, and 25.5% of licuri cake, respectively, in the total dry matter of the diet. The inclusion of licuri cake influenced the intake of dry matter, crude protein, ether extract, neutral detergent fiber corrected for ash and protein, and non-fibrous carbohydrates corrected for ash and protein, each of them showing quadratic behavior. There was an effect of the tested diets on the time spent on food intake and number of idle periods, which presented a quadratic effect, with maximum and minimum values obtained for the inclusion levels of the licuri cake of 16.92% and 11.00%, respectively. There was no effect of the tested diets on the time spent on rumination and idleness. The feed efficiency of the dry matter, the duration of the feeding period, and the duration of the idleness period were influenced by the inclusion of the licuri tart in the diet, presenting a linear decreasing effect. There was an increasing linear effect for the number of feeding periods and the duration of rumination periods. Given the results obtained, it can be concluded that the licuri cake changes the consumption and behavioral parameters of feedlot steers, being recommended its use in up to 8.5% of inclusion in the total dry matter of the diet.

Ingestive behaviour of steers grazing Brachiaria brizantha cultivar Marandu and in feedlot in Brazil.

The objective of this study was to evaluate the ingestive behaviour of steers grazing Brachiaria brizantha cv. Marandu and in feedlot regimen in Brazil. Fifty crossbred steers, with an average weight of 275 ± 8.18 kg, were distributed in a completely randomised design with five treatments and ten replicates per treatment (mineral supplementation, nitrogen supplementation, and concentrate supplementation at 0.1 and 0.2% of body weight and under feedlot conditions). Ingestive behaviour was assessed every 5 min for 24 h. No difference (P > 0.05) was found for grazing time among grazing systems. Conversely, rumination, idle, feeding, and chewing times showed differences (P < 0.05) only for feedlot animals. The time spent feeding at the trough was higher (P < 0.05) in animals receiving concentrate supplementation. The bite rate and the number of bites per day were similar (P > 0.05) among grazing systems. Feed and rumination efficiencies of dry matter and neutral detergent fibre corrected for ash and protein showed differences (P < 0.05) only in feedlot animals. Therefore, ingestive behaviour of steers varies with the raising system. Overall, feedlot animals showed better performance than grazing animals did, most likely due to longer rest periods.

Effect of different roughages sources on performance, milk composition, fatty acid profile, and milk cholesterol content of feedlot feed crossbred cows (Holstein × Zebu).

The aim of the study was to evaluate the effect of different forage sources in diets for feedlot dairy cows and their implications on production, composition, fatty acid profile, and milk cholesterol content. Nine Holstein × Zebu crossbred cows were distributed in three 3 × 3 Latin squares, in three periods of 21 days each, and three diets: elephant grass silage + concentrate, briquette from Brachiaria + concentrate, and sugarcane + concentrate. Elephant grass silage resulted in lower milk production and milk protein content. Cows fed elephant grass silage had lower concentrations of the saturated fatty acids C10:0, C11:0, C12:0, and C15:0 in the milk and higher of the unsaturated fatty acids C15:1, C16:1, C18:1n-9t, C18:1n-9c, C18:3n-6, CLAc9t11, and CLAt10c12 in relation to the other diets. Data were analyzed using the GLM procedure of the Statistical Analysis System (SAS) and the means were compared by the Tukey's test (P = 0.05). It is recommended to use the briquette from Brachiaria as a forage source for lactating cows, since it led to higher milk yield. On the other hand, the use of elephant grass silage as a forage source is recommended if the farmer is paid for milk with higher concentration of monounsaturated and polyunsaturated (CLA) fatty acids, which exerts beneficial effects on human health.

Inclusion of licuri meal in the diet of pasture dairy cows.

The objective of this study was to evaluate the inclusion of increasing levels of licuri meal as a substitute for soybean bran in the diet of pasture-based dairy cows and its effects on the intake, nutrient digestibility, and milk production and composition. Eight crossbred Holstein/Zebu cows were used in two 4 × 4 Latin square plots. The diets contained increasing percentage of licuri meal (0.0, 4.16, 7.09, and 9.45%) in the total diet, replacing soybean bran. The inclusion of licuri meal in the diet affected total dry matter intake and dry matter intake in relation to body weight, which presented a quadratic effect. The same behavior was observed for the consumption of EE, CP, TDN, and NDFap. The NFC consumption showed a linear decrease with the addition of the by-product in the diet. There was no influence of the inclusion of the licuri meal on the digestibility of the DM, CP, NFC, and TDN, while the digestibility of the NDFap and EE presented increasing linear effect. There was a reduction of milk production and food efficiency with the inclusion of increasing levels of the meal. The fat content in milk showed a linear increasing effect. Ditto for cholesterol. It is recommended to include not more than 7.00% of licuri meal for lactating cows with an average production of 20 kg day-1.

Feeding behavior of feedlot lambs fed diets containing levels of cassava wastewater.

In this study, we evaluated the effects of including cassava wastewater in the diet on the feeding behavior of feedlot lambs in 35 male uncastrated Santa Inês × Dorper crossbred lambs at an approximate age of 3 months, with an average live weight of 20.0 ± 3.4 kg. Diets were formulated with hay of cassava shoots (roughage) and a concentrate based on corn and soybean, with a roughage:concentrate ratio of 50:50, plus inclusion of cassava wastewater at the levels of 0, 12, 24, 36, or 48 g/kg of the total diet. Feeding behavior was evaluated between the 46th and 52nd days of the experiment. Increasing cassava wastewater levels in the diet reduced (P < 0.05) the intakes (kg/day) of dry matter and neutral detergent fiber as well as the efficiency of rumination (g/cud and g/h) of dry matter and neutral detergent fiber. The other behavioral parameters were not affected by wastewater inclusion in the diet. Therefore, the inclusion of up to 48 g/kg of cassava wastewater on fresh matter of diets is not recommended for feedlot lambs.

Ingestive behavior of grazing steers fed increasing levels of concentrate supplementation with different crude protein contents.

This study aimed to evaluate the ingestive behavior of steers on Brachiaria brizantha pasture fed diets with increasing levels of concentrate supplementation. Thirty-two crossbred steers in the finishing phase with average weight of 420 ± 8 kg were distributed in a completely randomized design with four treatments and eight replicates per treatment. Their behavior was assessed every 5 min for 24 h, in the middle of the experimental period. Variance and regression analyses at 0.05 % probability were adopted. The times spent grazing and ruminating reduced linearly (P <0.05), whereas the times spent at the trough (eating) and on other activities increased linearly (P <0.05) as the supplementation levels were elevated. The total feeding and chewing times decreased linearly (P <0.05) as the concentrate levels in the diet were elevated. By increasing the supplementation levels, the number of bites per day decreased linearly (P <0.05), and the feed efficiency of dry matter increased quadratically. Rumination efficiency of dry matter increased linearly (P <0.05) with increasing levels of concentrate supplementation. Grazing and rumination activities are reduced when the time devoted to other activities and at the trough are increased, as a result of the substitution effect.

Ingestive behavior of lambs fed diets containing castor seed meal.

The objective of this study was to evaluate the substitution of soybean meal for castor seed meal (CSM) in diets for feedlot lambs and the effects of these diets on their ingestive behavior. Fifty male Santa Inês lambs were used. The diets were composed of Tifton 85 hay and a concentrate containing detoxified CSM substituting 0, 25, 50, 75, or 100 % of the soybean meal. There was no effect (P > 0.05) of the CSM levels on the feeding, rumination, idle times, chews and time spent chewing per bolus, total chewing time, number of boli chewed, and number of chews per day. The dry matter (DM) intake decreased linearly (P < 0.05), but did not affect the neutral detergent fiber (NDF) intake. The feeding and rumination efficiencies had a quadratic response (P < 0.05). The experimental diets did not affect (P > 0.05) the numbers of feeding, rumination, and idle periods, but had a quadratic effect (P < 0.05) on the time per feeding activity and on the chewing periods. Substitution of soybean meal for detoxified CSM reduces the DM intake but does not change the ingestive behavior.

Feeding behavior of feedlot-finished young bulls fed diets containing peanut cake.

The objective of this study was to evaluate the feeding behavior of feedlot-finished young bulls fed diets containing peanut cake instead of soybean meal. A total of 32 Nellore young bulls with an initial body weight of 390 ± 43.5 kg were distributed in a completely randomized design. The animals were individually housed in stalls and fed Tifton 85 hay with four concentrate mixtures containing 0, 33, 66, or 100% peanut cake substituting for soybean meal. The diets were formulated to be isonitrogenous (with 15% crude protein) and isocaloric (with 65% total digestible nutrients), with a 40:60 forage:concentrate ratio, in the form of total mixed diet. The experimental period was 90 days, and data were collected every 28 days. Feeding behavior was assessed by means of observation and recording of the daily time spent feeding, ruminating, and idling, quantification of the periods and calculation of variables related to mastication characteristics as well as feeding and rumination efficiencies. Substitution of soybean meal for peanut cake in the diets caused a linear decrease in the intake of dry matter and neutral detergent fiber but did not affect the behavioral activities of the young bulls. Peanut cake may therefore replace up to 100% of soybean meal in the diet of feedlot-finished young Nellore bulls because it does not affect the feeding behavior of these animals.

Ingestive behavior and nitrogen balance of confined santa ines lambs fed diets containing soybean hulls.

The objective of this study was to assess the effect of substituting corn with soybean hulls on the ingestive behavior and nitrogen balance of Santa Ines lambs. A total of 25 lambs with an initial body weight of 20±2 kg at approximately six months of age, sheltered individually in stalls (1.10 m×1.0 m), considering an entirely casual experimental delineation. Soybean hulls were substituted for corn at 0, 250, 500, 750, and 1,000 g/kg of dry matter (DM). The time spent feeding, ruminating, masticating, and resting was not affected by the substitution of corn with soybean hulls. In fact, the feeding efficiency in g DM/h and the rumination efficiency in g DM/bolus increased linearly with soybean hull substitution in the feed. Although the nitrogen balance was not altered by the use of soybean hulls as a substitute for corn in the diets of Santa Ines lambs, the N ingested and N digested expressed in g/d, N retained as a percentage of that ingested, and N retained as a percentage of that digested displayed quadratic behavior. In conclusion, corn can be substituted with soybean hulls up to 1,000 g/kg of dry matter in the concentrate, without changing the ingestive behavior and nitrogen balance.

Biochemical changes, metal content, and spectroscopic analysis in sewage sludge composted with lignocellulosic residue using FTIR-MIR and FTIR-NIR.

The use of lignocellulosic residues, originating from sawdust, in composting sewage sludge for organic fertilizer production, is a practice of growing interest. However, few studies have explored the effect of the proportion of sawdust and sewage sludge raw materials on composting performance in the humification process. This study assessed the addition of sawdust in the sewage sludge composting process, regarding carbon content, presence of heavy metals, and humification of the organic compost. The experimental design employed was a randomized complete block design with five treatments featuring different proportions of organic residues to achieve C/N ratios between 30-1 (T1: 100% sewage sludge and 0% sawdust, T2: 86% sewage sludge and 14.0% sawdust, T3: 67% sewage sludge and 33% sawdust, T4: 55% sewage sludge and 45% sawdust, and T5: 46.5% sewage sludge and 53.5% sawdust) and five replications, totaling 25 experimental units. The addition of lignocellulosic residue in sewage sludge composting increased the levels of TOC and the C/N ratio, reduced the levels of pH, P, N, Na, Ba, and Cr, and did not interfere with the levels of K, Ca, Mg, S, CEC, labile carbon, and metals Fe, Zn, Cu, Mn, Ni, and Pb. The increase in the proportion of sawdust residue favored the degradation of aliphatic groups, increasing the presence of aromatic structures and reducing humification at the end of composting. The use of sawdust as a lignocellulosic residue in sewage sludge composting is a viable and efficient alternative to produce high-quality organomineral fertilizers.