Juan E Carulla

Supplementation of Acacia mearnsii tannins decreases methanogenesis and urinary nitrogen in forage-fed sheep

The objective of this experiment was to assess the effects of a partial replacement of ryegrass (Lolium perenne) by red clover (Trifolium pratense) or alfalfa (Medicago sativa) supplemented with 0 or 41 g Acacia mearnsii extract (containing 0.615 g/g condensed tannins)/kg dietary dry matter on nitrogen turnover and methane release by sheep, using the respiration chamber technique. Across all variables, there was no significant interaction between basal diet and tannin supplementation. The partial replacement of the grass by the legumes remained without effect on the amounts of nitrogen excreted through faeces or urine. Nitrogen and energy utilisation was lower (P < 0.05) with ryegrass-alfalfa than with ryegrass alone, and methane release (kJ/MJ gross energy intake) was higher (P < 0.05) with ryegrass-red clover than with ryegrass alone. Tannin supplementation decreased (P < 0.05) ruminal ammonia concentration and urinary nitrogen excretion without affecting body nitrogen and energy retention, and reduced (P < 0.001) methane release by 13% on average. The results suggest that supplemented Acacia mearnsii tannins can be useful in mitigating methane and potential gaseous nitrogen emissions, whereas a replacement of grass by legumes obviously shows no advantage in this respect.

Concentration of trans-vaccenic and rumenic acids in the milk from grazing cows supplemented with palm oil, rice bran or whole cottonseed

The changes in the concentration of trans-vaccenic (C18:1t-11) and rumenic (C18:2c-9,t-11) acids in the milk from cows grazing on Pennisetum clandestinum, fed a supplement containing palm oil, rice bran or whole cottonseed were evaluated. Three supplements were assessed: one control supplement containing palm oil (C), with a low concentration of linoleic acid mainly from palm oil, and two supplements containing rice bran (RB) or whole cottonseed (CS) as the main source of linoleic acid. Six Holstein cows (4.2±1.7 years of age, 532.5±50.7 kg BW, 125±29 days in milk and a milk yield of 21.7 5.8 kg d−1; Mean±SD) were assigned to each treatment using a double 3 × 3 × 3 Latin Square Design. Compared with treatment C, the milk fat concentrations of trans-vaccenic acid (31.1 and 23.8 g kg−1 of fatty acids for RB and C, respectively), rumenic acid (14.1 and 11.3 g kg-1 of fatty acid for RB and C, respectively) and unsaturated fatty acids (348.7 and 325.4 g kg−1of fatty acid for RB and C, respectively) were higher for RB. Compared with C and CS treatments, the Δ9-desaturase index was higher for RB (0.37, 0.35 and 0.34 for RB, C and CS, respectively) and the thrombogenicity index was lower (3.09, 3.43 and 3.50 for RB, C and CS, respectively). The atherogenicity index was lower for RB treatment compared with C, but not compared with CS (1.85, 2.03, 1.97 for RB, C and CS, respectively). Supplementing rice bran to grazing dairy cows is a good alternative for producing a kind of milk beneficial to human health, due to its higher concentrations of trans-vaccenic and rumenic acids, unsaturated fatty acids and lower thrombogenicity and atherogenicity indexes.

In vitro evidence for the importance of cultivation conditions on the effects of Calliandra tannins on ruminal escape of soybean protein and its post-ruminal degradability

Purified condensed tannins (CT) extracted from the legume Calliandra calothyrsus (var. San Ramón CIAT 22310), harvested in the dry and the rainy season and cultivated with low or high level of fertilization were added to soybean meal in a ratio of 600 mg/g of the incubated crude protein (CP). Effects on degradation either in ruminal fluid only, or in ruminal fluid followed by incubation in HCl/pepsin, were evaluated using a modified two-step in vitro method. Season was found to have larger effects on in vitro ruminal and post-ruminal CP degradation than fertilization. Condensed tannins from the rainy season harvest reduced ruminal CP degradation less than that from the dry season harvest. They had also less negative effects on the degradability of rumen escape protein and enhanced the proportion of post-ruminally degraded CP more than CT from the dry season harvest. An increase in level of fertilization reduced ruminal CP degradation in CT from the rainy season plants but this was not associated with effects on post-ruminal degradation. The study demonstrated the importance of environmental factors for the efficiency of CT in modifying ruminal and post-ruminal CP degradation.

Producción de metano in vitro en mezcla de gramíneas-leguminosas del trópico alto colombiano

In vitro methane production was determined in mixtures of grasses and legumes of Colombian highlands were evaluated using the gas production technique. Samples of two grasses, ryegrass (Lolium perenne) and kikuyu (Pennisetum clan-destinum), and two legumes, white clover (Trifolium repens) and big trefoil (Lotus uli-ginosus), from two different paddocks were harvested. The treatments were mixtures of kikuyu and lotus, kikuyu and white clover, ryegrass and lotus and ryegrass and clover in three different grass: legumes ratio (90:10, 70:30 and 50:50). The methane concentration in the gas was determined by gas chromatography. Methane production per unit of degraded dry matter decreased 14 % (p<0.05) when the proportions of legume increased associated with kikuyu. However, no differences were observed when legumes were mixed with ryegrass. When proportion of lotus, a tanniferous legume, increased total methane production decreased independently of grass suggesting an effect in methanogenic population.

Strategies for Reducing Methane Emissions from Ruminants (Estratégias para a Redução da Emissão de Metano por Ruminantes)

Ha fortes evidencias que as atividades humanas estao afetando o clima global por meio da producao de Gases de Efeito Estufa (GEE), dos quais o metano (CH4) tem elevado potencial de aquecimento. A fermentacao enterica e o esterco dos ruminantes representam cerca de 30 a 40% do total das emissoes antropogenicas de CH4. Este artigo traz um resumo de tecnologias existentes para reduzir as emissoes de CH4 entericas dos ruminantes, com enfase a manipulacao dietetica e ruminal, a selecao/reproducao animal e a melhoria dos sistemas de producao. As diferencas na producao de CH4 enterica entre as especies animais com base na anatomia do trato gastrointestinal, fisiologia digestiva, fermentacao ruminal e nos habitos de pastejo tambem sao discutidas. A inibicao da emissao de CH4 enterica e possivel por meio do uso de ionoforos, acidos orgânicos e oleos. Plantas alimentares contendo metabolitos secundarios (taninos e saponinas i.e.) tambem podem reduzir a producao de CH4. O uso de animais reprodutores para melhorar a eficiencia de conversao alimentar (menor consumo residual) pode contribuir com a reducao da emissao total de CH4, alem de reduzir a emissao por unidade de produto. Resultados utilizando o modelo IPCC nivel II preve que caprinos e vacas de elevada producao leiteira podem apresentar menor emissao de CH4 por unidade de produto em comparacao com animais zebuinos e ovinos, enquanto os pequenos ruminantes (caprinos e ovinos) produzem menos CH4 por unidade de ganho de peso corporal (carne), em relacao aos bovinos. A melhoria da qualidade das forragens e a implementacao de praticas eficientes de uso das pastagens (sistema de pastejo e taxas de lotacao) podem na maioria dos casos promover maior producao animal e incrementar a emissao absoluta de CH4, mas tambem reduzir a emissao de CH4 por unidade de produto animal. Palavras - chave: mudancas climaticas, gases do efeito estufa, bovinos, ovinos, caprinos, manipulacao da dieta, manipulacao ruminal, criacao de animais, intensificacao, modelagem. Estrategias para a Reducao da Emissao de Metano por Ruminantes A B S T R A C T There is irrefutable evidence that human activities are affecting the global climate through the production of Green House Gases (GHG) of which methane (CH4) has a high warming potential. Enteric fermentation and manure from ruminants represent about 30 to 40% of the total anthropogenic CH4 emissions. This paper summarizes existing technologies to reduce enteric CH4 emissions in ruminants given emphasis to dietary and rumen manipulation, animal selection/ breeding and improvement of production systems. Differences in enteric CH4 production among animal species based on anatomy of the GI tract, digestive physiology, rumen fermentation and grazing habits are also discussed. Inhibition of enteric CH4 emission is possible through the use of ionophores, organic acids and oils. Feeding plants containing secondary metabolites (i.e. tannins and saponins) can reduce CH4 production. Breeding for improved feed conversion efficiency (lower residual feed intake) is likely to reduce total and per unit product CH4 emissions. Results using the IPCC Tier II model predict that goats and high producing dairy cattle can potentially produce less CH4 emissions per unit of milk than Cebu cattle or sheep, while small ruminants (goats and sheep) produce less CH4 per unit of live weight gain (meat) than cattle. The introduction of improved high quality forages and the implementation of efficient pasture utilization practices (grazing system and stocking rate) can result in most cases in improved animal production and in increased absolute CH4 emissions, but in reduced CH4 per unit of animal product. Keywords: climate change, greenhouse gases, cattle, sheep, goats, dietary manipulation, rumen manipulation, animal breeding, intensification, modelling