This review deals with the most relevant limits and developments of the modeling of intake of she... more This review deals with the most relevant limits and developments of the modeling of intake of sheep and goats reared intensively and extensively. Because small ruminants are normally fed ad libitum, voluntary feed intake is crucial in feeding tactics and strategies aimed at optimal animal production. The effects of genetic, neuroendocrine, hormonal, feed and environmental factors on voluntary feed intake were discussed. Then, several mathematical models to estimate dry matter intake (DMI) were examined, with emphasis on empirical models for sheep and goats in intensive farm systems or in extensive areas under pasture or rangeland conditions. A sensitivity analysis of four models of prediction of DMI in housed lactating dairy sheep and meat sheep breeds was also presented. This work evidenced a large variability in the approaches used and in the variables considered for housed sheep and goats. Regarding the estimation of feed intake for grazing sheep and browsing goats, the accuracy of estimates based on empirical models developed so far is very low when applied out of the boundaries of the studied system. Feeding experiments indoors and outdoors remain fundamental for a better modeling and understanding of the interactions between feeds and small ruminants. However, there is a need for biological and theoretical frameworks in which these experiments should be carried out, so that appropriate empirical or mechanistic equations to predict DMI could be developed.
Application of a system dynamics model to evaluate the implementation of payment for environmental services as a reconversion mechanism in high mountain farming
Colombian mountain Páramos are considered natural areas with a very important role for human life... more Colombian mountain Páramos are considered natural areas with a very important role for human life. Páramos provide, both in mountain and lowland areas, a multitude of ecosystem services which start from vegetation to soil sustainability. The sustainability of Páramos is however impaired by several anthropogenic activities, including agricultural and livestock practices. A system thinking approach was applied in this work to improve the systemic understanding of factors affecting sustainability and resilience of Páramos agro-ecosystems. Interdisciplinary literature evidences were summarized and conceptually analyzed in order to develop causal loop diagrams of Páramo system structures allowing describing the main feedback loops involving (involved in/connecting) the Páramo ecosystem and driving its sustainability. From the causal diagram analysis few insights to maintain the human presence in Páramos arose. The system analysis highlights that human presence in Páramos should be stimulated, avoiding agriculture and livestock activities as the main income source. Particularly, social interactions, education on the Páramos environmental and relevance of agricultural practices to foster ecosystem services and multiple rentable economic activities should be enhanced. The study also includes the role of the government in providing the Páramo inhabitants with payments for ecosystem services and environmental education aimed to boost sustainability. Sustainable Páramo management will apply specific leverages on the system to reach Sustainable Development Goals 6 (water), 8 (economic growth, employment and work), 13 (climate change), and 15 (sustainable use of terrestrial ecosystems) of the Agenda 2030.
A direct assessment of the methane (CH4) emission level and its variability factors is needed in ... more A direct assessment of the methane (CH4) emission level and its variability factors is needed in each animal species in order to target the best mitigation strategy for the livestock sector. Therefore, the present study aimed to (1) test a laser methane detector (LMD) for the first time in Italian Mediterranean buffaloes (IMB), a non-invasive tool to quantify CH4 emissions; (2) test the effect of season on the emissions; and (3) compare the results measured directly with the ones estimated with the existing equations. CH4 emissions of twenty non-productive IMB, under the same feeding regimen, were monitored for 12 days in summer and winter. Significantly higher THI (74.46 ± 1.88 vs. 49.62 ± 4.87; p < 0.001), lower DMI (2.24 ± 0.04 vs. 2.51 ± 0.03% DMI/kg live weight; p < 0.001) and lower emission intensities (0.61 ± 0.15 vs. 0.75 ± 0.13; p < 0.001) were found during the summer period when compared with winter. LMD was found to be a versatile tool to be used in buffaloes, an...
Problemas de rentabilidad económica y eficiencia técnica en sistemas ganaderos de Ecuador
Revista Ecuatoriana de Ciencia Animal, Apr 9, 2020
sta revisión sistemática de la literatura integra los hallazgos de los estudios existentes sobre ... more sta revisión sistemática de la literatura integra los hallazgos de los estudios existentes sobre rentabilidad y la eficiencia técnica (ET) en granjas lecheras, una clasificaciónde la literatura anterior que proporciona la base para la síntesis. Se revisaronsistemáticamente 63estudios de investigación con encuestas con procedimientos rigurosos. La revisión se aplica a la investigación de la encuesta publicada. Se vincula el contexto socio-económico ambiental, las entradas al sistema y los productos con las variables que miden eficiencia. No hubo acuerdo entre los autores sobre el contexto y los determinantes de ET y EEs. Los principales determinantes fueron la ubicación geográfica, el tamaño de la finca, las inversiones en atención veterinaria, las prácticas de alimentación y ordeño y las técnicas de estimación del de la ET, las políticas públicas y las variables relacionadas con la gestión. Las implicaciones para los productoresde leche y los investigadores cierran la revisión. Una característica relevante que surge de la literatura es la falta de consenso con respecto a las técnicas de medición y determinantes de la ET, que sigue siendo un debate abierto. El hecho de que los datos se recopilaron en un período de casi 30 años en todos los continentes, refuerza la probabilidad de heterogeneidad entre las muestras y esto podría ser un fuerte argumento a favorde cambios en la rentabilidad y la eficiencia para generaruna discusiónexploratoria basada en evidencias de los estudiosy no dejar de tomar en cuenta los factores aquí discutidosThis systematic review of the literature integrates the findings of existing studies on profitability and technical efficiency (TS) in dairy farms, a classification of the previous literature that provides the basis for the synthesis. We systematically reviewed 63research studies with surveys with rigorous procedures. The revision is applied to the investigation of the published survey. The socio-economic environmental context is linked, the inputs to the system and the products with the variables that measure efficiency. There was no agreement between the authors on the context and the determinants of ET and EEs. The main determinants were the geographical location, the size of the farm, investments in veterinary care, feeding and milking practices and techniques for estimating the ET, public policies and variables related to management. The implications for milk producers and researchers close the review. A relevant characteristic that emerges from the literature is the lack of consensus regarding the measurement techniques and determinants of ET, which remains an open debate. The fact that the data was collected over a period of almost 30 years in all continents, reinforces the probability of heterogeneity between the samples and this could be a strong argument in favor of changes in the efficiency and to generate an exploratory discussion based on evidences of the studies and not fail to take into account the factors discussed her
El objetivo del estudio fue evaluar el efecto sobre el pastizal de Kikuyo y el crecimiento de vac... more El objetivo del estudio fue evaluar el efecto sobre el pastizal de Kikuyo y el crecimiento de vaconas Holstein, de diferentes dosis de Pollinaza como abono organico. El trabajo fue realizado en un sistema lechero de 21,6 ha en la provincia de Cotopaxi en Ecuador, ubicado en los 2o 13' Norte y 78o 24' Oeste, a 2651 msnm. Las precipitaciones promedian 1103 mm/ano y las temperaturas entre 14-21 ° C. La investigacion comparo tres niveles de fertilizacion organica con pollinaza (O, 50 y 100 kg/ha/ano, representados como Fo, Fso y F100) en pastizales de Kikuyo. Se utilizaron novillas de 210 kg de peso vivo y la concepcion del trabajo fue como un sistema para generar animales listos para la reproduccion. Los fertilizantes fueron aplicados manualmente en cada epoca para las dosis mayores. Se aplico riego por aspersion en seca. Se utilizo el pastoreo racional para la entrega de dos franjas de pasto/diaEl tiempo de reposo fue de 21-28 dias en todo el periodo. Se utilizo la suplementac...
The work is very inspiring and valuable. Following the manuscript structure, only minor comments ... more The work is very inspiring and valuable. Following the manuscript structure, only minor comments and suggestions, and editorial changes, were reported below: Minor points: Line 28: it is not clear the use of the word "confronted". We changed the word "confronted" by "face" Line 31: this effects is perhaps too far from the related noon. A possible modification of the sentence could be: "[..]can be used to evaluate perturbations…" Done Line 58: Please check the properness of the term "problems" in respect to milk yield We changed the word "problems" by "events"
Residual feed intake (RFI) is the most used measure of feed efficiency. However, considering the ... more Residual feed intake (RFI) is the most used measure of feed efficiency. However, considering the importance of concentrates in the ration, a new index, the residual concentrate intake (RCI), was here defined. RCI aims to measure the individual efficiency in converting the concentrate into animal products. Brown Swiss young bulls (N ¼ 736) were genotyped at 41,183 loci. Animals were housed in pens equipped with an automatic feeding system able to recognise the animal and record the concentrate intake. The diet consisted of concentrate and hay (ad libitum). The new RCI index was calculated as the residuals of the linear regression of concentrate intake on metabolic live weight and average daily gain. Animals were ranked according to their corrected RCI and divided into low (LRCI) and high phenotypes (HRCI). A low heritability (0.06 ± 0.03) was estimated using only genomics for this new index. Results from multivariate (M-GWAS) and Bayesian (B-GWAS) approaches were combined to identify SNP associated with RCI. The M-GWAS selected 698 SNPs potentially associated, whereas no significant markers were obtained in B-GWAS. Markers in the last approach were ranked according to their posterior inclusion probability and the first 698 were retained. Only SNPs in common between sorted B-GWAS and M-GWAS (N ¼ 11) were considered associated with RCI. A total of 48 candidate genes were retrieved near these SNPs. Most of them were previously reported to be associated with feed efficiency and RFI. The combined use of multivariate and Bayesian techniques allow to identify SNPs associated with the investigated trait. HIGHLIGHTS RCI could be promising to select animals 48 candidate genes were found associated with RCI Multivariate technique allowed to identify significant SNPs ARTICLE HISTORY
Microbial and chemical dynamics of brewers' spent grain during a low-input pre-vermicomposting treatment
Science of The Total Environment, 2022
The eco-sustainability of industrial processes relies on the proper exploitation of by-products a... more The eco-sustainability of industrial processes relies on the proper exploitation of by-products and wastes. Recently, brewers' spent grain (BSG), the main by-product of brewing, was successfully recycled through vermicomposting to produce an organic soil conditioner. However, the pre-processing step there applied (oven-drying) resulted in high costs and the suppression of microbial species beneficial for soil fertility. To overcome these limitations, a low-input pre-processing step was here applied to better exploit BSG microbiota and to make BSG suitable for vermicomposting. During 51 days of pre-treatment, the bacterial and fungal communities of BSG were monitored by denaturing gradient gel electrophoresis (DGGE). Chemical (carbon, nitrogen, ammonium, nitrate content, dissolved organic carbon) and biochemical (dehydrogenase activity) parameters were also evaluated. Mature vermicompost obtained from pre-processed BSG was characterized considering its legal requirements (e.g., absence of pathogens and mycotoxins, lack of phytotoxicity on seeds), microbiota composition, and chemical properties. Results obtained showed that throughout the pre-process, the BSG microbiota was enriched in bacterial and fungal species of significant biotechnological and agronomic potential, including lactic acid bacteria (Weissella, Pediococcus), plant growth-promoting bacteria (Bacillus, Pseudomonas, Pseudoxhantomonas), and biostimulant yeasts (Pichia fermentans, Trichoderma reesei, Beauveria bassiana). Pre-processing increased the suitability of BSG for earthworms' activity to produce high-quality mature vermicompost.
Colombian mountain Páramos are considered natural areas with a very important role for human life... more Colombian mountain Páramos are considered natural areas with a very important role for human life. Páramos provide, both in mountain and lowland areas, a multitude of ecosystem services which start from vegetation to soil sustainability. The sustainability of Páramos is however impaired by several anthropogenic activities, including agricultural and livestock practices. A system thinking approach was applied in this work to improve the systemic understanding of factors affecting sustainability and resilience of Páramos agro-ecosystems. Interdisciplinary literature evidences were summarized and conceptually analyzed in order to develop causal loop diagrams of Páramo system structures allowing describing the main feedback loops involving (involved in/connecting) the Páramo ecosystem and driving its sustainability. From the causal diagram analysis few insights to maintain the human presence in Páramos arose. The system analysis highlights that human presence in Páramos should be stimul...
What should be the policy to meet urban food needs in developing countries and those in transitio... more What should be the policy to meet urban food needs in developing countries and those in transition? This is a key question of the Food and Agriculture Organization of the United Nations (FAO), which was posed into the “FAO’s methodological and operational guide to study and understand Food Supply and Distribution Systems (FSDS) to cities in developing countries and countries in transition” in order to face the current overwhelming increase of urban population and the increasing urbanization pressures on food systems. Following some previous work in the field where it was argued that clarifying the various problems and structure behind Food Supply and Distribution Systems (FSDS) in urban environments is vital to assess policies that aim at meeting urban food needs, the purpose of this paper is to show that the methodological approach known as system dynamics modeling and simulation can lead, in terms of knowledge and/or theoretical contribution, to the unfolding of complexity in this...
Sustainability of Dairy Sheep Production in Pasture Lands: A Case Study Approach to Integrate Economic and Environmental Perspectives
RIVISTA DI STUDI SULLA SOSTENIBILITA', 2015
Sheep farming plays a large role in some specific economies, maintains strong links with natural ... more Sheep farming plays a large role in some specific economies, maintains strong links with natural resources, and produces multiple functions in rural areas. Its sustainability has to deal with different purposes. This study aims to assess economic and environmental sustainability of extensive dairy sheep farming in Sardinia. A case study approach was adopted in order to directly collect farm data and to integrate assessments on more dimensions of sustainability. We found that farm is not profitable without support of public financial aids. Furthermore, production of nitrogen is under the normative limit and greenhouses gas emission intensity, allocated with economic criteria, was equal to 2,3 and 16,1 kg of CO2eq emitted per kg of produced milk and meat, respectively. Empirical evidences suggest the need to better take into account environmental externalities and into the farmer’s choices. A public financial support system expressively based on minimizing environmental externalities might force farmers to incentive eco-sustainable production and guarantee them profitability.
Individual dry matter intake (DMI) is a relevant factor for evaluating feed efficiency in livesto... more Individual dry matter intake (DMI) is a relevant factor for evaluating feed efficiency in livestock. However, the measurement of this trait on a large scale is difficult and expensive. DMI, as well as other phenotypes, can be predicted from milk spectra. The aim of this work was to predict DMI from the milk spectra of 24 lactating Sarda dairy sheep ewes. Three models (Principal Component Regression, Partial Least Squares Regression, and Stepwise Regression) were iteratively applied to three validation schemes: records, ewes, and days. DMI was moderately correlated with the wavenumbers of the milk spectra: the largest correlations (around ±0.30) were observed at ~1100–1330 cm−1 and ~2800–3000 cm−1. The average correlations between real and predicted DMI were 0.33 (validation on records), 0.32 (validation on ewes), and 0.23 (validation on days). The results of this preliminary study, even if based on a small number of animals, demonstrate that DMI can be routinely estimated from the m...
Colombia raises 1.73% of global livestock inventory. Key challenges of the sector are to increase... more Colombia raises 1.73% of global livestock inventory. Key challenges of the sector are to increase the animal production in order to nutritionally sustain the growing population, to ensure a rational use of natural resources for agricultural purposes, either combining criteria of economic sustainability and social equity. Agriculture can be considered as networking factor for productive, environmental and social components. In Colombia development of rural areas comprised complex dynamics affected by low technological farming systems and conflicts over land use and ownership. Free trade and climate change also act on the system as exogenous variables. The use of modeling tools and methodologies, such as system thinking and system dynamics, could help to manage rural development policies taking into account different components and to analyze their interconnections within the system. This comprehensive approach can also be useful to stimulate a multidisciplinary focus on future trends...
Prenatal exposure to different diets influences programming of glucose and insulin metabolism in dairy ewes
Journal of Dairy Science, 2020
Nutrition in fetal and postnatal life can influence the development of several biological systems... more Nutrition in fetal and postnatal life can influence the development of several biological systems, with permanent effects in adult life. The aim of this work was to investigate in dairy sheep whether diets rich in starch or fiber during intrauterine life (75 d before lambing) and postnatal life (from weaning to first pregnancy; growth phase) program glucose and insulin metabolism in the female offspring during their first pregnancy. Starting from intrauterine life, 20 nulliparous Sarda ewes were exposed to 4 dietary regimens (n = 5 per group) based on different dietary carbohydrates during their intrauterine life and their subsequent growth phase: (1) the fiber (FI) diet during both intrauterine and growth life, (2) the starch (ST) diet during both intrauterine and growth life, (3) the FI diet in intrauterine life followed by the ST diet in the growth phase, and (4) the ST diet in intrauterine life followed by the FI diet in the growth phase. After the end of the growth phase, all growing ewes were fed the same diet and naturally mated. When ewes were pregnant, on average at 124 ± 2 d of gestation they were challenged with an intravenous glucose tolerance test, and peripheral concentrations of glucose and insulin were determined. Basal insulin concentrations were higher in ewes exposed to the ST diet (0.97 μg/L) than in ewes exposed to the FI diet (0.52 μg/L) in intrauterine life. After glucose infusion, glucose and insulin concentrations were not affected by intrauterine diet. Insulin resistance, determined by the homeostasis model assessment, was affected by the intrauterine × growth phases interaction. Insulin sensitivity, assessed by the quantitative insulin check index, was lower in ewes exposed to the ST diet than in those exposed to the FI diet in intrauterine life (ST = 0.28; FI = 0.30). Diet in growth life had no effect on glucose and insulin metabolism. In conclusion, starchy diets offered during intrauterine life but not during postnatal life increased basal insulin level and lowered insulin sensitivity during the first pregnancy. Nutritional strategies of metabolic programming should consider that exposure to starchy diets in late fetal life might favor the programming of dietary nutrient partitioning toward organs with high requirements, such as the gravid uterus or the mammary gland.
Uploads
Papers by Alberto Atzori