Luiz Gustavo Ribeiro Pereira

Glicerina bruta na dieta de cordeiros terminados em confinamento

The objective of this work was to evaluate the effects of crude glycerin (CG) inclusion, with 36.20% of glicerol, on finishing lamb diets on intake, nutrients digestibility, and productive and economical performance. Thirty‑five intact male lambs (Santa Ines), with 20±2.27 kg of initial average body weight were randomly assigned to five treatments, with six replicates. The treatments consisted of increasing crude glycerin levels on the diet: 0, 3, 6, 9 and 12% of diet dry matter. After ten days of adaptation, five animals were slaughtered to determine initial carcass dressing. After the adaptation period, 30 animals were housed in individual pens. When the group reached average body weight of 35 kg, animals were slaughtered. The CG levels had a negative linear effect on dry matter intake and average daily weight gain, and a quadratic effect on neutral fiber detergent digestibility corrected for ash and protein. Crude glycerin levels had also a quadratic effect on body weight at slaughter and feed‑to‑gain ratio (FGR). Crude glycerin with 36.20% of glycerol can be included in the diet of finishing lambs up to 6% of dry matter, optimizing the FGR and promoting economic benefits.

Carcass characteristics of feedlot lambs fed crude glycerin contaminated with high concentrations of crude fat

Thirty non-castrated male lambs with 20±2.3 kg average body weight (BW) were randomly assigned to five treatments consisted of different dietary concentrations of crude glycerin (CG; 0, 3, 6, 9 and 12% on DM basis) to evaluate the effects on performance, carcass and meat quality traits. A quadratic effect was observed for performance (P=0.04), final BW (P<0.01) and hot carcass weight (P<0.01). No effects of CG were observed (P>0.05) on carcass pH neither on shear-force, cooking loss and ether extract content in longissimus. The inclusion of CG tended to reduce the Zn content in meat (P=0.09). The data suggests that CG (36.2% of glycerol and 46.5% of crude fat) may be used in diets of finishing lambs with concentrations up to 3% without negative effects on performance and main carcass traits. Moreover, inclusion of CG seems to not affect quality and safety of meat for human consumption.

Nutritional evaluation of “Braquiarão” grass in association with “Aroeira” trees in a silvopastoral system

This study aimed at evaluating the influence of a silvopastoral system (SPS) composed of “Aroeira” trees (Myracrodruon urundeuva) on the nutritional value of Brachiaria brizantha cv. Marandu forage grass over the rainy season. The experiment was conducted in the SPS located in the “Cerrado” biome in Lagoa Santa County, Minas Gerais state, Brazil, in the agricultural year of 2004–2005. It was evaluated the influence of “Aroeira”, whose density in the area was 140 trees/ha, on the following parameters of the B. brizantha cv. Marandu forage grass: forage mass harvest above stubble height, morphogenic attributes, bromatological composition and nutritional value. The effects of “Aroeira” trees on the micro-climatic conditions were also evaluated. The experiment adopted a randomized block design with five blocks (cutting seasons), two treatments (a shaded pasture—B. brizantha cv. Marandu shaded by M. urundeuva—and a pasture in full sun—B. brizantha cv. Marandu in full sun), and three replicates. The tree component, composed of the tree species M. urundeuva in the experimental density adopted, increased dry matter and crude protein of the forage mass harvest above stubble height, without affecting the concentration of neutral detergent fibre or acid detergent fibre, thus causing dry matter and organic matter in vitro degradability as well as effective degradability of the forage grass to remain the same as those obtained in full sun. Therefore, the results of this study show the possibility of using trees and grass to increase both animal production and environmental services.

Cinética de fermentação ruminal de silagens de milheto

The dry matter digestibility and the fermentation kinetics of three pearl millet genotypes silages (BRS-1501, NPM-1, and CMS-3) were estimated by the semi-automated in vitro gas production technique, using a completely randomized blocks design in a split plot arrangement. The genotypes means were compared by SNK test (P<0.05) and fermentation kinetics parameters estimated by regression of gas production on time using the France model. The greater cumulative gas production from 24 hours on was obtained by BRS-1501 genotype silage. The dry matter degradability (DMD) values at 96 hours of incubation were 53.9% for BRS-1501, 51.7% for NPM-1, and 49.1% for CMS-3 silage. The lowest DMD (P<0.05) among the studied genotypes silages was observed for CMS-3 silage. The maximum potential of gas production ranged from 145.18ml/g of dry matter for CMS-3 genotype silage to 155.02ml/g of dry matter for BRS-1501 silage. The BRS-1501 genotype silage showed the highest potential of gas production and effective degradabilities.

Effect of fibrolytic enzymes added to a Andropogon gayanus grass silage-concentrate diet on rumen fermentation in batch cultures and the artificial rumen (Rusitec)

In vitro batch cultures were used to screen four fibrolytic enzyme mixtures at two dosages added to a 60 : 40 silage : concentrate diet containing the C(4) tropical grass Andropogon gayanus grass ensiled at two maturities - vegetative stage (VS) and flowering stage (FS). Based on these studies, one enzyme mixture was selected to treat the same diets and evaluate its impact on fermentation using an artificial rumen (Rusitec). In vitro batch cultures were conducted as a completely randomized design with two runs, four replicates per run and 12 treatments in a factorial arrangement (four enzyme mixtures×three doses). Enzyme additives (E1, E2, E3 and E4) were commercial products and contained a range of endoglucanase, exoglucanase and xylanase activities. Enzymes were added to the complete diet 2 h before incubation at 0, 2 and 4 μl/g of dry matter (DM). Gas production (GP) was measured after 3, 6, 12, 24 and 48 h of incubation. Disappearance of DM (DMD), NDF (NDFD) and ADF (ADFD) were determined after 24 and 48 h. For all four enzyme mixtures, a dosage effect (P>0.05) DM, N, NDF or ADF disappearance after 48 h of incubation nor daily ammonia-N, volatile fatty acids or CH(4) production. However, enzyme application increased (P<0.05) microbial N production in feed particle-associated (loosely-associated) and silage feed particle-bound (firmly associated) fractions. With A. gayanus silage diets, degradation may not be limited by microbial colonization, but rather by the ability of fibrolytic enzymes to degrade plant cell walls within this recalcitrant forage.

Production, Nutritional Quality and In vitro Methane Production from Andropogon gayanus Grass Harvested at Different Maturities and Preserved as Hay or Silage.

Andropogon gayanus is an important grass due to its high biomass production, drought tolerance and favorable growth on low fertility acidic soils. Currently, there is little research on the impact of growth stage on the nutritional quality or the degree of CH4 production that may arise from this forage during ruminal fermentation. The objectives of this study were to determine the effects of regrowth stage of A. gayanus on its chemical composition, in vitro production of gas and CH4, as well as in vitro dry matter (DM) digestibility when grown under tropical Brazilian conditions and conserved as hay or as silage. The nutritional value of A. gayanus grass declined with increasing maturity; however digestible DM yield linearly increased. After 112 d of regrowth, A. gayanus produced higher quality silage (higher lactate and lower pH and butyrate content) and higher DM yield. However, the low levels of crude protein at this time would make protein supplementation a necessity for proper rumen fermentation. No differences in CH4 kinetic parameters were found with advancing maturity or preservation method (hay or silage).

Consumo e digestibilidade aparente de silagens de sorgo em diferentes estádios de maturação

Avaliaram-se o consumo e a digestibilidade aparente, em ovinos, das silagens dos hibridos de sorgo BRS 610, BR 700 e BRS 655 colhidos em tres estadios de maturacao dos graos: leitoso, pastoso e farinaceo. Os valores de consumo da materia seca, em gramas por quilograma de unidade de tamanho metabolico (CMS-UTM), variaram de 45,90g/UTM/dia a 59,99g/UTM/dia e nao diferiram com o avanco do estadio de maturacao para todos os hibridos (P>0,05). No estadio pastoso, o BRS 655 apresentou menor CMS-UTM em relacao aos demais hibridos (P 0,05). Foi observado menor consumo de proteina digestivel para os hibridos com tanino, BR 700 e BRS 655, em relacao ao BRS 610 (P<0,05) nos estadios pastoso e farinaceo. Todos os tratamentos apresentaram balanco de nitrogenio levemente positivo, com valores entre 0,02g/UTM/dia e 0,20g/UTM/dia. Nao houve diferencas nos valores de digestibilidade da fibra entre os hibridos com tanino, BR 700 e BRS 655, e sem tanino, BRS 610. Recomenda-se a utilizacao da silagem do hibrido BRS 610, colhida no estadio pastoso. Os hibridos BRS 655 e BR 700 devem ser colhidos no estadio leitoso.

Technical note: Validation of a system for monitoring individual feeding behavior and individual feed intake in dairy cattle

The objective of this study was to validate an electronic system for monitoring individual feeding behavior and feed intake (Intergado Ltd., Contagem, Minas Gerais, Brazil) in freestall-housed dairy cattle. No data have been published that validate either the behavioral measurement or the feed intake of this system. Feeding behavior data were recorded for 12 Holstein cows over 5d using an Intergado system and time-lapse video. The cows were fitted with an ear tag containing a unique passive transponder and provided free access to 12 feed bins. The system documented the visit duration and feed intake by recording the animal identification number, bin number, initial and final times, and the difference between feed weight at start and end of each feed bin visit. These data were exported to Intergado web software and reports were generated. Electronic data on animal behavior were compared with video data collected during the same evaluation period. An external scale was used to manually measure and validate the electronic systems ability to monitor dairy cow feed intake for each feed bin visit. The feed intake was manually measured for 4-h time periods and compared with the sum of the feed intake recorded by the monitoring system for each cow visit during the same time period. Video and manual weight data were regressed on the electronic feeding behavior and feeding intake data to evaluate the precision of the monitoring system. The Intergado system presented high values for specificity (99.9%) and sensitivity (99.6%) for cow detection. The visit duration and feed intake per visit collected using the electronic monitoring system were similar to the video and manual weighing data, respectively. The difference between the feed intake measured manually and the sum of the electronically recorded feed intake was less than 250g (25,635±2,428 and 25,391±2,428g estimated using manual weighing and the electronic system, respectively). In conclusion, the Intergado system is a reasonable tool to monitor feeding behavior and feed intake for freestall-housed dairy cows.

Technical note: A facility for respiration measurements in cattle.

A respiration system consisting of 4 climate-controlled chambers and 1 set of flowmeters and analyzers was constructed and validated. Each chamber had volume of 21.10m(3) (3.68×2.56×2.24m) and was made from steel with double-glazed windows on either side enabling visual contact between animals. The chambers are independently climate-controlled and can maintain temperature and relative humidity in a range from 5 to 45°C and 30 to 80%, respectively. A flow generator and mass flowmeter continuously pull air from each chamber and a slight negative pressure inside the chamber is ensured. Air from all chambers and ambient air share a common gas analysis and data acquisition system for monitoring O2, CO2, and CH4 concentrations over the measurement period, with the cycle time set to 20min. Analyzers are regularly calibrated and the chambers have mean recoveries of 99.0 and 98.0% for CO2 and CH4, respectively. The chambers are equipped with infrared cameras and electronic feed and water bins for intake measurements, as well as sensors for monitoring animal position and heart rate. Data acquisition and analysis software is used to calculate the rate of consumption of O2 and production of CO2 and CH4. The dynamic respiration measurements are integrated with feed intake data and other sensors. The daily gas exchanges are estimated by integration to determine methane emission and heat production. We conducted a trial with 12 lactating 3/4 Holstein × 1/4 Gyr crossbred dairy cows (6 multiparous and 6 primiparous) under 2 feeding regimens (ad libitum or restricted) to validate the system. Two 22-h respiration measurements were obtained from each cow. Restricted-fed cows showed lower values for milk yield, methane emission, and heat production compared with ad libitum-fed animals. We found no difference between groups for CH4 produced per kilogram of dry matter intake. Repeatability for CH4 emission and heat production was high (0.97 and 0.92, respectively). The respiration system described herein is a useful tool for measuring the dynamic and accumulated data of heat production, methane emission, and feed intake.

In vitro Fermentation, Digestion Kinetics and Methane Production of Oilseed Press Cakes from Biodiesel Production

Following the extraction of oil for biodiesel production, oilseed press cakes are high in fat. As the dietary supplementation of fat is currently considered the most promising strategy of consistently depressing methanogenesis, it follows that oilseed press cakes may have a similar potential for CH4 abatement. As such, this study aimed to characterise the nutritive value of several oilseed press cakes, glycerine and soybean meal (SBM) and to examine their effects on in vitro ruminal fermentation, digestion kinetics and CH4 production. Moringa press oil seeds exhibited the greatest in sacco effective degradability (ED) of DM and CP (p<0.05). In vitro gas production (ml/g digested DM) was not affected (p = 0.70) by supplement at 48 h of incubation. In vitro DMD was increased with the supplementation of glycerine and SBM at all levels of inclusion. Moringa oilseed press cakes produced the lowest CH4 (mg/g digested DM) at 6 and 12 h of incubation (p<0.05). The findings suggest that moringa oilseed press cake at 400 g/kg DM has the greatest potential of the oilseed press cakes examined in this study, to reduce CH4 production, without adversely affecting nutrient degradability.