Juan Carlos Ku-Vera

Potential of condensed tannins for the reduction of emissions of enteric methane and their effect on ruminant productivity

El metano (CH4) es un gas subproducto de la fermentacion de los carbohidratos en el rumen. La agricultura contribuye con el 47% de las emisiones antropogenicas de CH4, siendo los rumiantes responsables del 39% de las emisiones de metano enterico. Este gas de efecto invernadero (GEI) tiene un potencial de calentamiento global 25 veces mas que el CO2 y representa una perdida de hasta el 12% de la energia total consumida por los rumiantes. Este trabajo describe los mecanismos de accion de los taninos condensados contenidos en follajes y frutos y su efecto en los microbios del rumen, asi como su potencial en la mitigacion de las emisiones de CH4. Los hallazgos sugieren que los taninos condensados reducen la poblacion de protozoos hasta 79%, reduciendo ademas los metanogenos del rumen hasta en 33%. Los taninos condensados se unen a proteinas y polisacaridos formando complejos, reduciendo asi la digestibilidad de la meteria seca y organica y la produccion de H2 metabolico, el que es usado por metanogenos para la reduccion del CO2 a CH4. Estudios in vitro sugieren que los taninos condensados pueden reducir el CH4 en el rumen hasta 63%, mientras que in vivo se han registrado reducciones hasta 58% en la produccion de CH4. Ademas, la incorporacion de taninos condensados en la racion de rumiantes tiene el potencial de aumentar la ganancia de peso en 26%, relacionando esto al aumento en el flujo de proteina de baja degradacion ruminal al intestino delgado o la reduccion de la energia perdida en forma de CH4 en el rumen. Se concluye que la incorporacion de taninos condensados en la racion de los rumiantes en concentracion de 3-6% de materia seca puede reducir las emisiones de CH4 asi como mejorar la ganancia de peso y produccion de leche de los animales productivos.

Milk production and reproduction of dual-purpose cows with a restricted concentrate allowance and access to an association of Leucaena leucocephala and Cynodon nlemfuensis

The aim of the study was to evaluate the productive and reproductive performance of dual-purpose (DP) cows with a restricted concentrate allowance and access to a forage association of Leucaena (Leucaena leucocephala) and Stargrass (Cynodon nlemfuensis). Twenty-four multiparous Holstein × Zebu cows were used during the first 98 days postpartum. Treatments were control (CT): nightly grazing of Stargrass + commercial concentrate (3.97 kg dry matter [DM]/d), and Leucaena (LT): nightly grazing of Stargrass + commercial concentrate (1.97 kg DM/d) + 4 h grazing on an association of Leucaena/Stargrass. The actual time spent browsing Leucaena represented 38% of the total time of consumption. The bite rate of Leucaena was 22 5 bites/min with a bite size of 0.541 ± 0.08 g DM. The estimated intake of Leucaena per cow was 503 ± 228 g DM/d. Milk yield per cow was similar (P > 0.05) between treatments (CT = 12.28 ± 0.6 kg/d, LT = 11.97 ± 0.6, TL = 11.9 0.6) with a similar composition (P > 0.05). There were no differences (P > 0.05) between treatments for changes in live weight (CT −29.6 kg, LT −33.3 kg) and body condition (CT −1.3, LT −1.4, in a 1–9 scale). Population of ovarian follicles per cow was similar between treatments throughout the experiment. Pregnancy rate was 33% for CT and 25% for LT, with no significant differences (P > 0.05). Grazing an association of Leucaena and Stargrass can replace part of the concentrate without detrimental effects on production and reproduction in DP cows.

Modeling methane emissions and methane inventories for cattle production systems in Mexico

Anaerobic fermentation of structural carbohydrates in the rumen of bovines produces waste products such as volatile fatty acids, fermentation heat, carbon dioxide and methane gas. Methane is a greenhouse gas having several times the global warming potential of CO2. The purpose of the present paper is to provide a realistic estimate of the national inventory of methane produced by the enteric fermentation of cattle, based on a simulation model and to provide estimates of CH4 produced by cattle fed typical diets from the tropical and temperate climates of Mexico. Predicted total emission of methane produced by the 23.3 million heads of cattle in Mexico is approximately 2.02 Tg/yr. It was concluded that the modeling approach was suitable in producing a better estimate of the national methane inventory for cattle. It is flexible enough to incorporate more cattle groups or classification schemes, productivity levels and a variety feed ingredients for cattle. The model could also be used to evaluate different mitigation strategies and serve as a tool to design mitigation policies.

Effect of supplementation with saponins from Yucca schidigera on ruminal methane production by Pelibuey sheep fed Pennisetum purpureum grass

The aim of the work was to determine the effect of increasing concentrations of saponins from Yucca schidigera in the diet on voluntary intake, rumen fermentation and methane (CH4) production in Pelibuey sheep fed a tropical grass Pennisetum purpureum. Five male sheep (32.2 ± 1.1 kg liveweight) were fed chopped P. purpureum grass in a 5 × 5 Latin square design. Sheep were supplemented with 0.0, 1.5, 3.0, 4.5 or 6.0 g per day of saponins from Y. schidigera mixed with ground corn, before the grass was offered. Feed intake, feed refusal and total faecal output were recorded for 20 days of the adaptation period and 5 days of the experimental period. Apparent digestibility of dry matter (DMD), organic matter (OMD), neutral detergent fibre (NDFD) and acid detergent fibre (ADFD) were determined. Ruminal methane emission was estimated using stoichiometric balance and the molar proportion of volatile fatty acids was determined by gas chromatography. Voluntary intake, DMD, OMD, NDFD, ADFD, volatile fatty acids and CH4 emission were not affected (P > 0.05) by increasing inclusion levels of saponins in the ration of sheep. Nonetheless, CH4 production increased as the voluntary intake of NDF augmented. Addition of 6 g of saponins per day as a supplement to Pelibuey sheep fed a tropical grass did not affect voluntary intake and digestibility of DM, OM, NDF and ADF, or ruminal methane production.

Effect of intake of diets containing tannins and saponins on in vitro gas production and sheep performance

The aim of this study was to evaluate the effect of the intake of leucaena, Enterolobium cyclocarpum, fruits and a mixture of both feeds on in vitro gas production and in vivo sheep productive performance. The experiment was conducted at the University of Yucatan, Mexico. Twenty-four Pelibuey sheep, 20.28 ± 2.99 kg average liveweight (LW), were used. Animals were randomly assigned to the following experimental treatments: T1: 100% Pennisetum purpureum, T2: 30% Leucaena leucocephala foliage + 70% P. purpureum, T3: 30% E. cyclocarpum fruits + 70% P. purpureum, T4: 30% L. leucocephala foliage + 30% E. cyclocarpum fruits + 40% P. purpureum. Voluntary intake was higher in T4 (grass + leucaena + E. cyclocarpum) (P = 0.0001). Higher LW gain was observed in animals fed with T4 (P = 0.0001) and the lowest LW gains were recorded with grass (T1) and grass + leucaena (T2) (78.9 and 99.2 g/day, respectively). Similarly, the feed conversion efficiency was improved with treatment T4 (P = 0.0030). The in vitro gas production (48 h) was lower by 30 mL/0.5 g fermented DM in T4 compared with the other treatments (P = 0.0001). Apparent DM digestibility was higher in T3 and T4 (P = 0.0005). The protozoa counts were lower in T2, T3 and T4 (P = 0.0001). Higher intake, digestibility and sheep performance with diets containing grass + leucaena + E. cyclocarpum mixture arise from an improved nutritional diet as these sources have higher protein, lower cell walls and higher DM digestibility.

Effect of Fatty Acids on Reproductive Performance of Ruminants

Different types of fats have been utilized in an attempt to improve reproductive function in ruminant animals. Fatty acids derived from plants and oil seeds have exerted a major impact on reproductive performance, some of the most common sources include sunflower, linseed, cottonseed, rapeseed and soyabean. Animal fat (tallow) and calcium salts of saturated fatty acids may escape in a significant percentage rumen hydrogenation to be incorporated into adipose tissue and milk. Fish by-products contain a high proportion of polyunsaturated fatty acids (PUFAs) and pass without being altered in the rumen exerting no effects on rumen fermentation. Each dietary source of fat varies regarding composition of specific fatty acids (Table 1). Early studies of the effect of fat in the ration on reproductive performance were carried out by Burr & Burr (1930), who observed that fat deficiency in the ration of growing rats induced alterations in ovulation rate and on the onset of oestrus, while lipid supplementation reestablished reproductive performance of the females, coining the concept of essential fatty acids. In later studies, research was aimed at evaluating the effect of fat supplementation in different animal species both ruminant and non-ruminant, on reproductive aspects such as the establishment of puberty (Smith et al., 1989), semen production (Castellano et al., 2010), maternal recognition of pregnancy (Abayasekara & Wathes, 1999, Filley et al., 2000, Lopes et al., 2009) by means of the suppression of luteolytic signals (Mattos et al., 2000), restart of ovarian activity after parturition (de Fries et al., 1998), follicle development, quality of oocytes (Staples & Thatcher, 2005; Bilby et al., 2006c), and of the embryo (Cerri et al., 2009), modification in the mechanism of synthesis and secretion of hormones involved in reproductive processes (Staples et al., 1998) and on production aspects such as quality of milk (Rego et al., 2004; Bernal et al., 2010) or meat (Wood et al., 2003). Due to the fact that some fatty acids (FA) are essential for mammals and to the role of fatty acids on reproductive processes, it is possible that cattle reproduction will be influenced more by the type of lipids consumed than for the total lipid intake. This is particularly important since ruminants hydrogenate PUFAs in the rumen, limiting the amount of PUFAs that are absorbed from the small intestine (Thatcher & Staples, 2007,

Effect of dehydrated pig faeces in the diet on microbial protein synthesis and fermentation balance in the rumen of Holstein steers.

Abstract Salcedo-Meza, J.R., Castellanos-Molina, R., Garza-Flores, J.D., Tejada-Castañeda, Z.I., Velázquez-Madrazo, P.A., Segura-Correa, J.C., Rodríguez-Vázquez, R. and Ku-Vera, J.C. 2003. Effect of dehydrated pig faeces in the diet on microbial protein synthesis and fermentation balance in the rumen of Holstein steers. J. Appl. Anim. Res., 25: 17–25. The effect of incorporation of four levels (20, 25, 30 and 35% dry matter basis) of dehydrated pig faeces (DPF) on fermentation balance and microbial protein synthesis in the rumen was investigated. DPF were fed in complete rations consisting of sorghum grain, sorghum straw and cane molasses. Four Holstein steers (273±31 kg) and cannulated in the rumen and proximal duodenum were used in a 4 x 4 Latin square design and fed 8478g DM/day. Rumen pH was not affected, but the concentration of NH3-N (3.7, 6.2, 12.5 and 18.4 mg/100 ml) in rumen fluid was increased with graded levels of DPF in the ration. True rumen degradability of organic matter was linearly reduced (P<0.01) and microbial nitrogen synthesis (66.7 to 89.8g/d) and true efficiency of bacterial growth (14.8 to 22. Og N/kg OMAFR) were linearly increased (P<0.01) with graded levels of DPF. Relative molar proportion of VFAs in the rumen was basically acetic (63.2 to 66.0 mol/100 mol). Energy loss as CH4, energy retained in VFAs and the amount of ATPs produced per mol of glucose fermented was unaltered. Results suggest that incorporation of DPF in the ration improves rumen environment and efficiency of microbial growth in the rumen and consequently the availability of microbial nitrogen in the small intestine is also increased.

Turix, a dynamic mechanistic model for feed evaluation

The objective of this study was to use the Turix model (a new mechanistic dynamic model that can be used for feed evaluation under tropical conditions), along with in situ and in vitro sugar cane experimental data from a previous study, to evaluate sugar cane kinetics through estimation of three parameters associated with ruminal bacterial growth: kM,SmL, the substrate uptake; kLM, the bacterial growth from intermediate metabolite; and YVFAP,FS, the products related to volatile fatty acid yield. Values of these parameters for the whole sugar cane and its neutral detergent fiber (NDF) and acid detergent fiber (ADF) fractions were: a) kM, SmL, 16.20, 50.47 and 21.97 mL h-1 (mg M)-1 ; b) kLM, 96.00, 543.00 and 1,680.00 h-1 ; and, 1.02, 0.40 and 0.23 g g-1 , respectively. Results from the model adjustment showed a slow microbial substrate uptake c) Y VFAP, FS and a low biomass yield for whole sugar cane. The highest substrate uptake was obtained for NDF, while the highest biomass yield was obtained for ADF. The interrelation between the parameters kM, SmL showed to be important for biological and Y VFAP, FS description of microorganism growth and VFAP and biomass production.

Effect of Dehydrated Pig Faeces in the Ration on Rumen Degradability, Kinetics of Passage and in vivo Digestibility in Holstein Steers

Abstract Salcedo-Meza, J.R., Castellanos-Molina, R. Garza-Flores, J.D., Tejada-Castañeda, Z.I., Segura-Correa, J.C., Rodríguez-Vázquez, R. and Ku-Vera, J.C. 2004. Effect of dehydrated pig faeces in the ration on rumen degradability, kinetics of passage and in vivo digestibility in Holstein steers. J. Appl. Anim. Res., 25: 109–116. To assess the effect of 20, 25, 30 and 35% dehydrated pig faeces (DPF) in rations based on sorghum and cane molasses four Holstein steers in a 4 x 4 Latin square design were fed 2.6 kg DM/100 kg LW/day. Rumen degradability for DM and OM of DPF among rations did not differ (P>0.05). Potential degradation of DM and CP of sorghum straw was improved (P<0.01) when the level of DPF in the ration was increased. Effective degradability for DM and CP of DPF increased gradually (P<0.01) with levels of DPF. The lowest extent of OM effective degradability (P<0.01) was observed at the highest (35%) level of DPF in the ration. Effective degradability for CP of sorghum straw increased (P<0.01) and that for DM and OM changed (P<0.01) only at the highest level of inclusion of DPF. Rate of passage of digesta through the reticulo-rumen decreased linearly (P<0.01) with the inclusion of DPF. In vivo digestibilities for DM, OM, AD F and NDF decreased and for CP increased with graded levels of DPF in the ration (P<0.01). In conclusion. DPF can be included up to 35% of DM in the ration of beef cattle, without negatively affecting rumen fermentation.

Ewes production in a pasture of star grass (Cynodon nlemfuensis) fertilized with swine lagoon effluent

A study was carried out to evaluate the effect of fertilizing star grass (Cynodon nlemfuensis) with effluents from swine lagoon on weight gain of Pelibuey ewes. Two stocking rates (69.4 ewes ha−1 versus 97.2 ewes ha−1) and two rest periods (21 days versus 28 days), were compared using eight paddocks of 720 m2 each (two replicates per treatment). The paddocks were fertilized with 300 kg ha−1 of N, divided in three applications and were irrigated during the dry season. Ewes were allowed to graze for 24 h per day, with water and a mineral supplement freely available. Live weight was recorded at 28 day intervals. Herbage mass, crude protein and neutral detergent fiber (NDF) concentration were evaluated in plots (2m×1 m) with 300 and 450 kg ha−1 of N, cutting every 21 or 28 days, in four replicates. Weight gains were higher (P<0.01) at medium than at high stocking rates (53.4 g per day versus 40.5 g per day). Weight gain per hectare was higher (P<0.01) for the resting interval of 21 days as compared with 28 days (3.7 kg ha−1 per day versus 3.2 kg ha−1 per day). The application of swine lagoon effluent on star grass increase dry matter production and allows an increase in stocking rate.