Crecimiento posdestete de búfalos (Bubalus bubalis, Artiodactyla, Bovidae) sometidos a pruebas de desempeño provenientes de dos sistemas de manejo predestete: cría sin ordeño y doble propósito

ABSTRACT: the objective of this study was to compare growth traits in buffaloes reared in farms using a pre-weaning management system with no milking (NM), or a dual-purpose system (DP: meat and milk production). Methods: performance tests were conducted at the Experimental Station of the University of Antioquia, located in Barbosa (Antioquia, Colombia). Buffaloes were confined and fed with fresh Maralfalfa grass (Pennisetum sp.) ad libitum, plus two kilograms of mixed plus two 2 kilograms of concentrate supplement per day. Weight, ultrasound, and bovinometric measurements were taken every 14 d. Bovinometric measurements were chest girth (CG), height at withers (HW), and height at sacrum (HS). Ultrasound measurements were Longissimus muscle area (REA) and rump fat thickness (RFT). Traits were analyzed using a linear regression and second order polynomial model using unstructured variance-covariance matrices and accounting for relationships among animals. Results: all the traits in DP animals, as well as RFT, HW, and HS in NM animals fit well with a second-order regression mixed model. Weight, CG, and REA in NM animals fit well with a first-order regression mixed model. The rate of increase for HW and HS declined at the end of the test in NM animals, while weight, CG, RFT, and REA did not. The DP buffaloes displayed an accelerated rate of increase for all traits towards the end of the evaluation. The non-zero estimates of genetic variances for random regression effects suggests that these characteristics may be improved genetically in Colombia. Environmental and genetic differences among farms may have influenced the high variability among individuals for the intercept. Conclusions: the linear regression variances were small for all traits, suggesting that although selection of animals within these performance tests is possible, expected changes in the buffalo population will be small.RESUMEN: El objetivo de este estudio fue comparar características de crecimiento de búfalos sometidos a pruebas de desempeño, pertenecientes a dos sistemas de producción: cría sin ordeño (CSO) y doble propósito (DP). Métodos: las pruebas se realizaron en la Estación Experimental de la Universidad de Antioquia, ubicada en Barbosa, Colombia. Los animales fueron confinados y alimentados con pasto Maralfalfa (Pennisetum sp.) y dos kilogramos de un suplemento concentrado por día. El peso, las medidas de ultrasonido y bovinométricas fueron tomadas cada 14 días. Las medidas bovinométricas fueron perímetro torácico (PT), altura a la cruz (AC) y altura al sacro (AS). Las medidas por ultrasonido fueron área del músculo Longissimus (AOL) y espesor de grasa de la cadera (EGC). Las características fueron analizadas utilizando un modelo de regresión lineal mixto de primer orden y polinomial de segundo orden, con matrices de varianzas y covarianzas sin estructura, teniendo en cuenta la matriz de parentesco entre los animales. Resultados: todas las características en los animales provenientes del sistema DP y las caracteristicas EGC, AC y AS en animales de CSO, presentaron un mejor ajuste al modelo de regresión de segundo orden. El peso, PT y AOL en animales de CSO ajustaron mejor con un modelo de regresión de primer orden. La tasa de incremento de AC y AS en los búfalos de CSO declinó al final de la prueba, mientras que las otras características no presentaron disminución. Los búfalos del sistema DP aceleraron la tasa de incremento para todas las características al final de la evaluación. Las varianzas genéticas estimadas para los coeficientes de regresión fueron diferentes de cero, sugiriendo que estas características pueden ser mejoradas genéticamente en Colombia. Diferencias ambientales y genéticas entre fincas pueden haber influido en la alta variabilidad del intercepto entre los individuos. Conclusiones: las varianzas de los coeficientes de la regresión lineal fueron pequeñas para todas las características, sugiriendo que, aunque la selección de animales en pruebas de desempeño es posible, los cambios esperados en la población de búfalos serán pequeños

Uso de la excreción de creatinina como método alternativo a la colecta total de orina en vacas holstein.

La investigación en producción animal requiere la recolección total de orina, para estimar la excreción de compuestos nitrogenados y derivados púricos, lo cual trae grandes dificultades, siendo necesario buscar técnicas alternas. El objetivo de este trabajo fue determinar el volumen de orina de vacas Holstein por colecta total con arneses y por muestras puntuales”spot”, utilizando la excreción de creatinina como marcador interno y evaluar la variación en la excreción diaria de creatinina utilizando colectas durante siete días. El volumen de orina observado (colecta total) y el estimado (muestra spot) fueron comparados por una prueba de medias de datos apareados (5% de probabilidad). La comparación entre días de colecta se realizó mediante un modelo mixto con medidas repetidas en el tiempo, del mismo animal (efecto aleatorio) y día de evaluación (efecto fijo). Se utilizó el procedimiento MIXED y el comando REPEATED del programa SAS (2001). Para la correlación entre el volumen de orina observado y estimado se utilizó PROC CORR y para la regresión PROC REG de SAS (2001). La excreción de creatinina promedio fue de 29,89 mg/kg PV/día. No se encontró diferencia entre las dos técnicas. El volumen de orina obtenido fue 19,8 L y el estimado 19,7 L. Se encontró una alta correlación entre las dos técnicas (r=0,82;

Enteric methane emissions of zebu steers fed with tropical forages of contrasting nutritional value

Methane (CH4) emissions from livestock contribute significantly to climate change and diet plays a fundamental role in the emissions generated. Research in animal nutrition should aim at identifying ways to increase production efficiency with the least possible environmental impact and manipulation of diet quality becomes one of the most viable options to both mitigate emissions and increase animal productivity

Enteric methane emissions of zebu steers fed with tropical forages of contrasting nutritional value

Methane (CH4) emissions from livestock contribute significantly to climate change and diet plays a fundamental role in the emissions generated. Research in animal nutrition should aim at identifying ways to increase production efficiency with the least possible environmental impact and manipulation of diet quality becomes one of the most viable options to both mitigate emissions and increase animal productivity

Feeding strategies to increase nitrogen retention and improve rumen fermentation and rumen microbial population in beef steers fed with tropical forages

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

Technical and environmental characterization of dual-purpose cattle farms and ways of improving production: A case study in Colombia

There are few reports on dual-purpose cattle systems characterization in Latin America and Colombia based on large datasets. This limits our understanding of their dynamics, and the establishment of public policies and government programs to improve their productive performance, promotion and rural development. This study aimed to characterize very small, small, medium, and large dual-purpose farms in Colombia from technical and environmental perspectives. The data analysed were obtained from the Ganadería Colombiana Sostenible and the LivestockPlus projects, which gathered information from a total of 1313 dual-purpose farms in Colombia. Farms were classified as being either very small (1 to 30 bovines), small (31 to 50 bovines), medium (51 to 250 bovines), or large farms (more than 251 bovines). Numerical and categorical variables were distributed into five components: (1) General Farm Information, (2) Herd Composition and Management, (3) Pasture Management, (4) Production Information, and (5) Environmental Information. Each component was analysed using the factorial analysis of mixed data (FAMD) method. According to FAMD, for the components General Farm Information, Herd Composition and Management, Pasture Management, and Production Information, the distribution of variables led to a spatial separation of the centroid from each category of producers. For the component Environmental Information, there was no separation of the centroid. In general, medium-sized and large farms showed better infrastructure, better machinery and equipment, and better reproductive practices; however, this was not reflected in a significant improvement of productive parameters, except for a lower mortality rate. Larger livestock producers need to plan their livestock husbandry activities properly, based on their better available infrastructure and livestock management practices, with the purpose of increasing productivity. The main features identified for each livestock producer category can be the basis to guide and establish policies and programmes for their technological development. The development of better livestock management practices and the implementation of technology, as well as technical assistance, should focus on small- and medium-sized livestock producers, which could lead to reaching a better productive and reproductive performance of dual-purpose systems

Environmental impact of primary beef production chain in Colombia: Carbon footprint, non-renewable energy and land use using Life Cycle Assessment

In Colombia, the beef production chain accounts for approximately 11.6 million cattle heads and annually produces 933 million kg of the beef carcass. There are no life cycle assessment (LCA) studies that have evaluated the environmental performance of Colombian beef systems. The present study aimed to estimate the carbon footprint (CF), non-renewable energy use, and land use of 251 cow-calf and 275 fattening farms in Colombia. The study also aimed to identify the main hotspots of adverse environmental impacts and propose possible mitigation options and their cost-effectiveness. The impact categories were estimated using the 2006 IPCC and the 2019 Refinement to 2006 IPCC guidelines, databases, and locally estimated emission factors. The functional units used were 1 kg fat and protein corrected milk (FPCM) and 1 kg live weight gain (LWG), leaving the farm gate. Three methods of allocating environmental burdens to meat and milk products were applied: economic, energy, and mass allocation. The adoption of improved pastures was considered a mitigation measure, and an economic assessment was performed to estimate the relative cost-effectiveness of its establishment. A principal component multivariate analysis and a Hierarchical Clustering on Principal Components were performed. The economic allocation method assigned a greater environmental burden to meat (83%), followed by energy content (80%) and mass production (73%). The largest sources of GHG emissions were enteric fermentation and manure deposited on pasture. Both cow-calf and fattening systems had a cluster of farms with better productivity, pasture and cattle management practices, and environmental performance. The CF for meat could be reduced by 33 to 56% for cow-calf and 21 to 25% for fattening farms, by adopting improved pastures. Therefore, our results suggest that GHG emissions can be reduced by adopting improved pastures, better agricultural management practices, efficient fertilizer usage, using the optimal stocking rate, and increasing productivity

Life Cycle Assessment of small, medium and large dairy cattle farms in Colombia

In Colombia, cattle production is responsible for 31% of greenhouse gas (GHG) emissions from the agricultural sector. Dairy farms account for 15% of the Colombian cattle herd. Life Cycle Assessment (LCA) of GHG emissions from these farms are not common, and when performed, are based on a small number of farms. LCA is important because the identification of appropriate GHG mitigation actions requires larger data sets. This study quantified the carbon footprints (CF) on 192 dairy farms in Colombia by using LCA methodology. Farms were classified according to their herd size: small (0-30 animals; n=94), medium (31-50; n=32), large (>50; n=66). Emissions were estimated using the GHG emission factors reported in the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, and locally estimated emission factors. A “cradle to farm gate” system boundary was established, and a physical allocation method proposed by the International Dairy Federation, was used to distribute GHG emissions between co-products. The functional units were 1 kg fat and protein corrected milk (FPCM) and 1 kg live weight gain (LWG). The CF (kg CO2-eq kg-1FPCM/LWG) for medium (1.6 FPCM and 13.8 LWG) and large farmers (1.6 FPCM and 13.1 LWG) were the lowest among the categories. The medium and large farm categories were characterized by implementing better pasture and herd management practices, by the highest milk productivity (3240.8 and 3645.6 kgFPCM Cow-1Year-1) and stocking rate (4.5 AU ha-1;4.4 AU ha-1). It is possible to improve the environmental performance of farms by increasing productivity and adopting better agricultural practices

Uso del suelo en sistemas de cría y ceba bovina de diferente tamaño en 13 departamentos en Colombia

En 2016, el hato bovino colombiano alcanzó 22,689,420 de cabezas, de los cuales, el 41.2% corresponde a la cadena de producción de carne, cría y ceba. En los sistemas de pastoreo extensivo tradicional y mejorado se localiza el 90% del inventario ganadero correspondiente a la producción de carne. Este carácter extensivo y el bajo valor nutritivo de las gramíneas tropicales ha generado estancamiento del inventario y baja productividad. Mediante los estudios de caracterización se identifican las variables productivas, reproductivas, económicas y sociales que más inciden en la heterogeneidad y homogeneidad entre fincas. Esto permite desarrollar paquetes tecnológicos para incrementar la productividad. El bajo número de caracterizaciones limita el conocimiento del uso del suelo agropecuario y se torna en una barrera para el establecimiento, formulación y gestión de políticas agropecuarias encaminadas al mejoramiento productivo. El objetivo del presente trabajo es mostrar algunas características del uso del suelo agropecuario de las fincas orientadas hacia la cría y ceba, pertenecientes a muy pequeños, pequeños, medianos y grandes ganaderos localizados en 13 departamentos de país