Trends in greenhouse gas emissions from dairy cattle in Mexico between 1970 and 2010

The objective of the present work was to estimate and assess trends in greenhouse gas (GHG) emissions, particularly methane (CH4) and nitrous oxide (N2O), from dairy cows in Mexico from the base year of 1970 to 2010. Empirical and mechanistic models were used to estimate enteric methane emissions based on chemical composition of diets. Methane from manure was calculated using Intergovernmental Panel for Climate Change (IPCC) and US Environmental Protection Agency recommended equations. N2O emission was calculated according to IPCC recommendations. Compared with the 1970s, current management practices using modern dairy cows increased feed conversion efficiency 32% and milk yield 62%. GHG emission intensity (i.e. emissions per unit of product) was reduced 30%, 25% and 30% for CH4, N2O and total emissions, respectively. The study showed that although GHG emissions in absolute terms increased in the past 40 years, emission intensity decreased due to higher level of production. This trend is likely to continue in the future, assuming milk production follows the same increasing trend as in other countries in North America. © 2014 CSIRO

4to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

Este volumen acoge la memoria académica de la Cuarta edición del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2017, desarrollado entre el 29 de noviembre y el 1 de diciembre de 2017 y organizado por la Universidad Politécnica Salesiana (UPS) en su sede de Guayaquil. El Congreso ofreció un espacio para la presentación, difusión e intercambio de importantes investigaciones nacionales e internacionales ante la comunidad universitaria que se dio cita en el encuentro. El uso de herramientas tecnológicas para la gestión de los trabajos de investigación como la plataforma Open Conference Systems y la web de presentación del Congreso http://citis.blog.ups.edu.ec/, hicieron de CITIS 2017 un verdadero referente entre los congresos que se desarrollaron en el país. La preocupación de nuestra Universidad, de presentar espacios que ayuden a generar nuevos y mejores cambios en la dimensión humana y social de nuestro entorno, hace que se persiga en cada edición del evento la presentación de trabajos con calidad creciente en cuanto a su producción científica. Quienes estuvimos al frente de la organización, dejamos plasmado en estas memorias académicas el intenso y prolífico trabajo de los días de realización del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad al alcance de todos y todas

Effects of Prosopis laevigata pods on carcass characteristics, non-carcass components, meat quality, fatty acid profile and sensory attributes

It was hypothesized that feeding mesquite pods to male Rambouillet lambs would have no negative effects on carcass characteristics, meat chemical composition and fatty acid composition of Longissimus thoracis et lumborum (LTL). Twenty-one male lambs (2.5 months old and 21 ± 1.44 kg bodyweight) were randomly assigned to one of three experimental diets, two of which replaced maize grain and stover with mesquite pods (Prosopis laevigata) (PL): 0 g PL/kg feed (PL0), 250 g PL/kg feed (PL250) and 500 g PL/kg feed (dry matter basis). The feeding trial lasted 72 days. Carcass traits, chemical composition, fatty acid profile, and sensory characteristics of meat were measured. Carcass linear dimensions, non-carcass components, digestive tract and offal, compression value, and chemical composition of meat were similar in all treatments. Dietary inclusion of PL decreased carcass shrinkage loss. Lambs fed PL500 had better muscle conformation and degree of fat. Meat produced by PL-fed lambs was well accepted by panellists who judged meat appearance, colour, flavour, juiciness, toughness, and stringiness. In lambs fed PL0, the LTL muscle was lighter and yellower than that of animals fed PL250 and PL500 diets. Fatty acid composition was altered. The PL0 diet resulted in lower percentages of total trans fatty acids (TFA) and saturated fatty acids (SFA) and higher percentages of most unsaturated fatty acids (UFA) and polyunsaturated fatty acids (PUFA) n-6 compared with PL250 and PL500 diets. Mesquite diets of up to 500 g/kg dry matter (DM) for growing lambs improved carcass quality and nutritional parameters of the meat. Keywords: Mesquite, muscle conformation, rumen conten

Efecto de la especie y madurez sobre el contenido de nutrientes de cladodios de nopal

El uso forrajero del nopal es amplio y su calidad nutrimental muy variable. A pesar de los estudios realizados se desconoce con precision la magnitud con que la especie y la madurez del cladodio afectan su contenido de nutrientes. El objetivo de esta investigacion fue evaluar el efecto de la especie de nopal (Nopalea cochenillifera, Opuntia robusta ssp. larreyi, O. undulata¿~O. tomentosa y O. ficus-indica) y del estadio de crecimiento (cuatro niveles, de nopalito tierno -EC1- a cladodio bien desarrollado -EC4-) sobre el porcentaje de materia seca (MS), proteina cruda (PC), fibra extraida con detergente neutro o acido (FDN y FDA) y cenizas; en cladodios producidos en hidroponia en invernadero. Se utilizo un diseno de bloques completos al azar con arreglo factorial 4¿~4 con cuatro repeticiones. La MS disminuyo (p.0.05) de 5.7% en el EC1 a 3.9% en el EC3, a partir del cual aumento con tasa de variacion distinta entre especies. La PC fue estadisticamente similar entre especies y disminuyo significativamente (p.0.05) de 21.7% en el EC1 a 16.9% en el EC4. O. ficus-indica presento los mayores valores de FDN y FDA (34.4 y 17.6%). Los contenidos de FDN y FDA se incrementaron significativamente con el crecimiento. El contenido de cenizas aumento significativamente con el crecimiento, de 26.4% en EC1 a 31.9% en EC4, de manera diferenciada entre especies

Nutritive value of ensiled pig excreta, poultry litter or urea with molasses or bakery by-products in diets for lambs

The objective of this study was to evaluate the nutritive value of maize stover silage diets containing pig excreta (PE), poultry litter (PL) or urea as nitrogen (N) sources, and sugarcane molasses (MOL) or bakery by-products (BBP) as energy sources. The study was designed as a 6 × 6 Latin square with six ruminal cannulated Hampshire rams (56 ± 5.7 kg body weight) in a 3 × 2 factorial arrangement of treatments. The quality of silages was good because of acceptable pH (4.1), texture and odour. Gas production was higher for diets with silage containing PL than that containing PE (287 vs. 269 mL/g DM). The fermentation rate of diets with MOL was higher than with BBP (0.07 vs. 0.05/h). The in vitro degradation, feed intake and N excretion of diets that contained PL were higher than with PE silage. Feed intake for diets with silage that contained BBP and PL or PE was lower than that containing MOL. Rumen pH was increased in lambs fed diets with silage that contained urea (6.38) or PL (6.25), compared with lambs fed diets containing PE silage (6.04). Dry matter (DM) and organic matter (OM) disappearances were higher for diets with silage containing PL compared with those containing PE or urea (650 vs. 606 and 594 g/g DM; 620 vs. 574 and 594 g/g OM, respectively). The N retention and total tract digestion were similar for all treatments. It was concluded that diets with PL and MOL silage had higher nutritive values than those containing PE or urea.Keywords: Digestion; fermentation rate; nitrogen balance; silage qualit

Enzimas fibrolíticas exógenas en la digestibilidad in vitro de cinco ecotipos de Brachiaria

Enzimas fibrolíticas exógenas en la digestibilidad in vitro de cinco ecotipos de Brachiaria. Este experimento se llevó a cabo en la Estación Experimental del Colegio de Postgraduados, en Montecillo, Estado de México, México, durante el 25 abril y el 27 noviembre de 2002. Se usó la primera fase de la técnica de Tilley y Terry (3, 6, 12, 24, 48, 72 h incubación) con el objetivo de medir el efecto de un compuesto enzimático fibrolítico exógeno (enzima; Fibrozyme®; 0 y 1,5 g enzima/kg MS) en la digestibilidad in vitro (DIV) de MS, FDN y FDA de henos de cinco ecotipos de Brachiaria [brizantha var. Toledo (BT); ruziziensis x decumbens CIAT 46024 (RD); decumbens var. Señal (DS); ruziziensis x brizantha CIAT 36061 cv. Mulato (RBM); brizantha var. Insurgente (BI)]. La DIVMS a las 48 y 72 h, para 0 y 1,5 g enzima, fue mayor (p < 0,05) para los ecotipos BT y BI, respecto a RD, DS y RBM. La DIVFDN a las 48 y 72 h, para 0 y 1,5 g enzima, fue mayor (p < 0,05) para BT y BI, respecto a RD, DS y RBM. La enzima aumentó (p < 0,05) la DIVFDN sólo para el ecotipo RD a las 72 h; además, incrementó la DIVFDA para BT a 12 h; BT y DS a 24 h; BT, RD y BI a 48 h. Por tanto, las enzimas fibrolíticas aumentaron la digestibilidad in vitro de la pared celular de cinco ecotipos de Brachiaria

A cell junction pathology of neural stem cells leads to abnormal neurogenesis and hydrocephalus

Most cells of the developing mammalian brain derive from the ventricular (VZ) and the subventricular (SVZ) zones. The VZ is formed by the multipotent radial glia/neural stem cells (NSCs) while the SVZ harbors the rapidly proliferative neural precursor cells (NPCs). Evidence from human and animal models indicates that the common history of hydrocephalus and brain maldevelopment starts early in embryonic life with disruption of the VZ and SVZ. We propose that a "cell junction pathology" involving adherent and gap junctions is a final common outcome of a wide range of gene mutations resulting in proteins abnormally expressed by the VZ cells undergoing disruption. Disruption of the VZ during fetal development implies the loss of NSCs whereas VZ disruption during the perinatal period implies the loss of ependyma. The process of disruption occurs in specific regions of the ventricular system and at specific stages of brain development. This explains why only certain brain structures have an abnormal development, which in turn results in a specific neurological impairment of the newborn. Disruption of the VZ of the Sylvian aqueduct (SA) leads to aqueductal stenosis and hydrocephalus, while disruption of the VZ of telencephalon impairs neurogenesis. We are currently investigating whether grafting of NSCs/neurospheres from normal rats into the CSF of hydrocephalic mutants helps to diminish/repair the outcomes of VZ disruption