The effect of the inclusion of Leucaena leucocephala and Tithonia diversifolia in Zebu steers receiving a diet based on improved pastures such as Brachiaria decumbens and Brachiaria hybrid cv Cayman ...on nitrogen (N) excretion, urinary volume and rumen microbial population was evaluated. To determine the dry matter intake and nutrient excretion, eight steers were used in a 4 × 4 Latin square design consisting of four periods and four diets. Four of them were cannulated for ruminal fluid extraction and quantification of ruminal microorganisms in three times of grazing (T0, T7 and T15). Forage intake was calculated through the external marker titanium dioxide. Diet including forages with superior protein content generated an increase in the gene copy numbers of Prevotella ruminicola and total bacteria on 15 sampling day (p < 0.001). Animals receiving diets with the dietary inclusion of Leucaena and Tithonia had daily N intakes of 228 and 113.5g N intake d−1, of which they excreted 42% and 61%, respectively. Inclusion of both protein forages increased daily urinary volume (9% and 7% d−1), with respect to the pasture-based diet. This study revealed that the inclusion of 18% Leucaena in a pasture-based diet improves the dry matter intake and N retention in Zebu steers under tropical conditions.
A decline in pasture productivity is often associated with a reduction in vegetative cover. We hypothesize that nitrogen (N) in urine deposited by grazing cattle on degraded pastures, with low ...vegetative cover, is highly susceptible to losses. Here, we quantified the magnitude of urine-based nitrous oxide (N
O) lost from soil under paired degraded (low vegetative cover) and non-degraded (adequate vegetative cover) pastures across five countries of the Latin America and the Caribbean (LAC) region and estimated urine-N emission factors. Soil N
O emissions from simulated cattle urine patches were quantified with closed static chambers and gas chromatography. At the regional level, rainy season cumulative N
O emissions (3.31 versus 1.91 kg N
O-N ha
) and emission factors (0.42 versus 0.18%) were higher for low vegetative cover compared to adequate vegetative cover pastures. Findings indicate that under rainy season conditions, adequate vegetative cover through proper pasture management could help reduce urine-induced N
O emissions from grazed pastures.
Antecedentes: Los sistemas de ganadería bovina son considerados emisores de gases efecto invernadero; sin embargo, algunos de sus componentes como el suelo, permiten la captura de carbono. Objetivo: ...Comparar las existencias de carbono en suelos cultivados con pasto kikuyo por varios años y suelos con coberturas de bosque o de helechal bajo diferentes geoformas, en fincas del Norte de Antioquia. Métodos: Se empleó un diseño en bloques aleatorizados, donde los bloques correspondieron al tipo de cobertura. Los tratamientos en arreglo factorial 3x5, comprendieron las geoformas y los muestreos. Se consideraron en el modelo los efectos de las geoformas (cóncavo, convexo y plano), tipo de cobertura (kikuyo, bosque y helechal) y profundidad de muestreo (0-20, 20-40, 40-60, 60-80 y 80-100cm). Se realizaron análisis de varianza para las variables: cantidad de carbono en el suelo y raíces finas y gruesas, tallos, hojas, estolones y biomasa muerta; densidad aparente y el pH del suelo. Resultados y conclusiones: Se encontró que las existencias de carbono en los primeros 0-20cm de profundidad fueron de 100t ha-1, comparadas con 20t ha-1 a 80-100cm de profundidad (p<0.05). Se presentó diferencia en las existencias de carbono aportadas por las raíces a 0-20 y 20-40cm de profundidad. Las distintas coberturas analizadas no afectaron la densidad aparente del suelo y fue menor para el relieve cóncavo. Contrario a lo esperado, el cambio de uso del suelo de bosque a pasturas de kikuyo no presenta efectos significativos en las existencias de carbono del suelo desde la superficie hasta un metro de profundidad bajo las condiciones evaluadas.
Methane (CH
) emissions from enteric fermentation in cattle are an important source of greenhouse gases, accounting for about 40% of all agricultural emissions. Diet quality plays a fundamental role ...in determining the magnitude of CH
emissions. Specifically, the inclusion of feeds with high digestibility and nutritional value have been reported to be a viable option for reducing CH
emissions and, simultaneously, increase animal productivity. The present study aimed to evaluate the effect of the nutritional composition and voluntary intake of diets based on tropical forages upon CH
emissions from zebu steers. Five treatments (diets) were evaluated: Cay1:
hybrid cv. Cayman (harvested after 65 days of regrowth: low quality); Cay2: cv. Cayman harvested after 45 days of regrowth; CayLl: cv. Cayman +
; CayLd: cv. Cayman +
; Hay:
hay as a comparator of common naturalized pasture. For each diet representing different levels of intensification (naturalized pasture, improved pasture, and silvopastoral systems), CH
emissions were measured using the polytunnel technique with four zebu steers housed in individual chambers. The CH
accumulated was monitored using an infrared multigas analyzer, and the voluntary forage intake of each animal was calculated. Dry matter intake (DMI, % of body weight) ranged between 0.77 and 2.94 among diets offered. Emissions of CH
per kg of DMI were significantly higher (
<
) in Cay1 (60.4 g), compared to other treatments. Diets that included
forage legumes had generally higher crude protein contents and higher DMI. Cay1 and Hay which had low protein content and digestibility had a higher CH
emission intensity (per unit live weight gain) compared to Cay2, CayLl and CayLd. Our results suggest that grass consumed after a regrowth period of 45 days results in lower CH
emissions intensities compared to those observed following a regrowth period of 65 days. Diets with
inclusion showed advantages in nutrient intake that are reflected in greater live weight gains of cattle. Consequently, the intensity of the emissions generated in the legume-based systems were lower suggesting that they are a good option for achieving the emission reduction goals of sustainable tropical cattle production.
Plenary paper presented at the International Leucaena Conference, 1‒3 November 2018, Brisbane, Queensland, Australia.Leucaena leucocephala has played a key role in the development of sustainable ...cattle ranching in Latin America. This species is the backbone of the so-called Intensive Silvopastoral Systems (ISPS) that combine high-density cultivation of leucaena as fodder shrubs (4,000–40,000 plants/ha) with grasses and trees. The layers of vegetation added by shrubs and trees increase the system’s capacity for transforming solar energy into biomass and enhance habitat complexity. Although part of the biomass is transformed into livestock products, a significant amount is deposited as litter on the soil and, along with the nitrogen fixed by leucaena and other trees, has positive effects on soil properties and grass production. The increased complexity of the system has measurable effects on biodiversity. ISPS with leucaena support more species of birds, ants, dung beetles and woody plants than conventional pasture monocultures, contribute to landscape-scale connectivity and provide environmental services. They also enhance animal welfare through reduced heat stress and improved availability and quality of fodder resources. ISPS contribute to climate change mitigation by improving above- and below-ground carbon sequestration and by cutting down greenhouse gas emissions per units of dry matter consumed and cattle product. Although these systems have been successfully implemented in Colombia, Mexico and other countries, their adoption is still limited in relation to the area suitable for their introduction.
Pasture conditions influence the nutrients use efficiency and nitrogen (N) losses from deposited excreta. Part of the N is lost as nitrous oxide (N
2
O), a potent greenhouse gas. The objective of ...this study was to characterize apparent N recovery in milk of dual-purpose cattle and to quantify N
2
O emissions from the urine they deposit following grazing on
Megathyrsus maximus
cv. Mombasa. The N content in the grass and the milk produced by the cattle and the milk urea N (MUN) content were quantified in two contrasting regions of Colombia (Casanare and Atlántico). Dry matter intake (DMI) by the cattle was estimated using the Cornell Net Carbohydrate and Protein System. We used a closed static chamber technique to measure N
2
O emissions from soils in areas with and without urine patches (21 days in Atlántico and 35 Days in Casanare). Estimated DMI values were 11.5 and 11.6 kg DM day
−1
, milk production was 6.5 and 5.9 L day
−1
, apparent N recovery in milk was 24 and 23%, and the MUN content was 4.4 and 17.2 mg N dl
−1
in Casanare and Atlántico, respectively. N applied to soil in the form of urine corresponded at rates of 20 and 64 g N m
−2
and net cumulative N
2
O emissions were 350 and 20 mg N
2
O-N m
−2
in Casanare and Atlántico, respectively. Despite low digestibility of offered diet, N recovery in milk was above the values reported at dairy cattle in tropical conditions. High urine-N inputs at Atlántico site did not result in high N
2
O emissions suggesting that the default Tier 1 emission factor (EF) which is based on N inputs would have overestimated urine-based N
2
O emissions in Atlántico. Comparing previous studies conducted in Colombia, we observed inter-regional differences by urine-based N
2
O emissions. This observation suggests that to increase certainty in estimating urine-based N
2
O emissions, Colombia needs to move toward more region-specific Tier 2 EF and reduce its dependence on the default IPCC Tier 1 EF. In addition, the adoption of Tier 2 EF in the cattle sector will facilitate accounting for the effect of animal diets on N
2
O inventories.
This study evaluates the effects of the inclusion of two different Leucaena species as a source of condensed tannins based on in vitro fermentation, methane production and post-ruminal protein supply ...in a diet based on Urochloa hybrid cv. Cayman CIAT BR02/1752 grass. Under in vitro conditions, Leucaena leucocephala CIAT 17263 and Leucaena diversifolia ILRI 15551 were incubated in two proportions (25% and 50% w/w) with Cayman grass and with/without polyethylene glycol as a tannin-binder. The results show that substrates with Leucaena diversifolia produced less gas and methane than those with Leucaena leucocephala with and without polyethylene glycol. The mass in undegraded feed + solid associated microbes fraction decreased linearly with increasing level of inclusion of both species of Leucaena, while increasing its nitrogen content. It is concluded that the condensed tannins of Leucaena diversifolia possess the superior activity and that the tannin content of both evaluated Leucaenas did not affect the diet degradation, and reductions in post-ruminal protein did not occur in the present study. Further studies are needed to differentiate the tannins present in different Leucaena species and their dietary effects.
Rumen fermentation and methanogenesis are vital metabolic processes in cattle and are carried out by microbial populations that are affected by dietary factors such as secondary metabolites, ...nutritional composition and degradability. The aim of this study was to monitor populations of total bacteria, total methanogens and Butirivibrio fibrisolvens in the rumen of Lucerne heifers fed on diets typical of intensive silvopastoral systems (ISS) or of a traditional (control) system. Rumen contents (RC) were collected orally from eight heifers consuming 100% Cynodon plectostachyus (control) and 76% C. plectostachyus + 24% Leucaena leucocephala (ISS) following a crossover design and DNA was extracted and quantified by quantitative PCR. Populations Log10 (ng g-1 RC) were 5.6 and 5.8 for total bacteria (p = 0.5343), 3.6 and 3.5 for B. fibrisolvens (p = 0.4742) and 5.0 and 5.3 for total methanogens (p = 0.2661) respectively in control and ISS diets. However, when measured in a separate parallel study, enteric methane emissions (g kg-1 of fermented dry matter) were significantly reduced with the inclusion of L. leucocephala. This fact indicated the importance of investigating the structure, function and interactions of populations beyond quantitative analysis to determine how diet affects rumen microbial populations and their function.
Keynote paper presented at the International Leucaena Conference, 1‒3 November 2018, Brisbane, Queensland, Australia.The demand for milk and dairy products globally is expected to grow in future ...decades, leading to an increase in the global dairy cattle population. Therefore it is important to identify production options that both improve efficiency and help reduce negative effects on the environment. Intensive silvopastoral systems have been proposed as a sustainable strategy in the tropics to increase the availability and quality of forage throughout the year for milk production from cattle. This paper reports the effects of silvopastoral systems that include leucaena at the farm level on milk production and on the environment in both Colombia and Mexico. Evaluation of different milk production systems has shown that the leucaena-based systems increased milk production both per cow and per hectare, increased the production of milk solids, improved the fatty acid profile in the milk and resulted in environmental benefits when compared with conventional systems.
Tithonia diversifolia is a shrub with excellent forage characteristics that has shown a wide genetic and phenotypic diversity. The objective of this study was to determine the biomass production and ...nutritional quality of seven genotypes of T. diversifolia with outstanding characteristics for ruminant nutrition, to analyze the Genotype x Environment (GxE) interaction of biomass production and to compare the performance of these genotypes with grasses offered normally in tropical conditions. For the GxE interaction the AMMI and SREG models were used, and evaluations were made in three environments. In the GxE analysis, the interaction was significant and effects of the environment on biomass productivity were observed with differences between genotypes (p <0.05). In the three environments, the chemical composition was adequate to be offered to ruminants. It is worth noting the high content of crude protein (28.89 g/100 g of dry matter - DM), the low fiber content (30.95 g of neutral detergent fiber - NDF/100 g of DM) and the high percentages of in vitrodegradation of DM for all the genotypes. It is possible to conclude that there are superior genotypes of T. diversifolia with the ability to have good productive and adaptive performance for high-altitude and low-altitude zones with low fertility soils.
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