Browsing by Author "Vargas-Bello-Perez, Einar"

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    Adaptation strategies based on the historical evolution for dairy production systems in temperate areas: A case study approach
    (2020) Toro-Mujica, Paula; Vera, Raul; Pinedo, Pablo; Bas, Fernando; Enriquez-Hidalgo, Daniel; Vargas-Bello-Perez, Einar
    Dairy production systems are heterogeneous as they are influenced by farm location and structure, markets, environmental conditions, and the producers' preferences and peculiarities. A typology of the existing dairy systems in Chile was developed with the objective of identifying homogenous groups that would allow for the characterization of adaptation strategies to changing environmental, social, technological, political and economic variables. Multivariate analyses were performed on data from official surveys carried out in 2009, 2011, 2013, and 2015. Six groups (I-VI) were identified representing 26.9%, 21.5%, 21.6%, 14.6%, 6.8% and 8.6% of the population surveyed. Group I was the largest, and it included non-specialized commercial dairies. Group II clustered semi-extensive, medium to large dairies that rely mostly on high yielding improved pastures. Group III included small, semi-extensive commercial farms that make a more intense use of pastoral resources, such as sown pastures and improved native grasslands. Groups IV, V, and VI corresponded to specialized dairies, highly market-oriented, that use annual forages to supplement intensively managed and planned pastures, but that differ in size and some management strategies. The observed temporal changes and adaptations over time were closely linked to farm size, intensity in the use of various technologies, the number and the breed of the dairy cows, and the presence of other agricultural activities in the property. The effect of variable prices of milk and system inputs differed by group. Given the social and economic importance of dairies throughout Central and Southern Chile, a number of interventions are proposed, including technical modifications, extension initiatives, and changes in policies.
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    Characterisation of dairy female calf management practices in southern Chile
    (2022) Toro-Mujica, Paula; Gebauer, Ricardo; Tajonar, Karen; Keim, Juan P.; Vargas-Bello-Perez, Einar
    The objective of this study was to characterise husbandry and technical-productive practices at the calf rearing stage in dairy farms in Los Lagos Region, southern Chile. A face-to-face survey was applied to 22 dairy farms in Los Lagos Region in 2017. All farms performed artificial calf rearing under either of two systems: total barn confinement (48%) or a mixed system that considers the first stage with confinement and the second stage in open-air paddocks (52%). More than half (52%) of the farms supplied fresh colostrum to the calf from its dam and the rest of the farms used bottle or oesophageal tube. Only 30% of the farms evaluated colostrum quality using colostrometer (densimeter) or refractometer. After the colostrum supply, milk replacers, waste milk, or a mixture of both were used for calf feeding. Most of the farms (66.7%) did not have automated milk-feeding systems and used bottles (88.9%) and buckets (11.1%) instead. On average, calves were handled by 1.5 caretakers (SD: 0.63) of which 63.4% (SD: 40.2) were men. The average age for caretakers was 43.9 years (SD: 12.7), with 23.8% being less than 35 years old. Overall, results from this study can be used to identify key managements that could improve calves' rearing productive traits.
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    Chemical Composition, Fatty Acid Profile and Sensory Characteristics of Chanco-Style Cheese from Early Lactation Dairy Cows Fed Winter Brassica Crops
    (2021) Vargas-Bello-Perez, Einar; Geldsetzer-Mendoza, Carolina; Ibanez, Rodrigo A.; Rodriguez, Jose Ramon; Alvarado-Gillis, Christian; Keim, Juan P.
    Simple Summary
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    Development and Characterization of Films with Propolis to Inhibit Mold Contamination in the Dairy Industry
    (2023) Abarca, Romina L.; Vargas, Francisco; Medina, Javiera; Paredes, Juan Carlos; Lopez, Bernardo Carrillo; Ortiz, Pablo A. A.; Vargas-Bello-Perez, Einar
    Due to the number of polyphenols with multiple biological activities, propolis has high potential to be used as an active agent in food protective films. Therefore, this study aimed to develop and characterize a sodium alginate film with ethanolic extract of propolis (EEP) for its potential use as protective active packaging against filamentous fungi in ripened cheese. Three different concentrations of EEP were analyzed: 0, 5 and 10% w/v. The films obtained were characterized, assessing thermal and physicochemical properties, as well as the concentration of polyphenols in the EEP and antifungal activity of the active films. The incorporation of EEP in the films generated thermal stability with respect to the loss of mass. Total color values (Delta E) of the films were affected by the incorporation of the different concentrations of EEP, showing a decrease in luminosity (L*) of the films, while the chromatic parameters a* and b* increased in direct proportion to the EEP concentration. Antifungal activity was observed with a fungistatic mode of action, stopping the growth of the fungus in cheeses without development of filamentous molds, thus increasing the shelf life of the ripened cheese under the analytical conditions, over 30 days at room temperature. Overall, EEP can be used to prevent growth and proliferation of spoilage microorganisms in cheese.
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    Influence of dietary oils rich in omega-6 or omega-3 fatty acids on rumen microbiome of dairy cows
    (2023) Cancino-Padilla, Nathaly; Gajardo, Felipe; Neves, Andre Luis Alves; Kholif, Ahmed Eid; Mele, Marcello; Huws, Sharon A.; Loor, Juan J.; Romero, Jaime; Vargas-Bello-Perez, Einar
    Lay Summary When cows are fed with different dietary lipid sources, some changes are found at the rumen level which is later reflected in overall animal's metabolism and performance. This study determined the effect of dietary lipids on rumen bacteria communities. For this, 15 cows were divided into three groups and were assigned a control diet and then this diet was supplemented with either soybean oil or fish oil. Results show minor effects on bacteria communities regardless of dietary lipid sources.
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    Long-Term Effects of Dietary Olive Oil and Hydrogenated Vegetable Oil on Expression of Lipogenic Genes in Subcutaneous Adipose Tissue of Dairy Cows
    (2019) Vargas-Bello-Perez, Einar; Bionaz, Massimo; Sciarresi-Arechabala, Pietro; Cancino-Padilla, Nathaly; Morales, Maria Sol; Romero, Jaime; Leskinen, Heidi; Garnsworthy, Philip C.; Loor, Juan J.
    The objective of this study was to characterize the long-term transcriptomic effects of lipogenic genes in subcutaneous adipose tissue (SAT) of dairy cows supplemented with unsaturated (olive oil; OO) and saturated (hydrogenated vegetable oil; HVO) lipids. Cows were fed a control diet with no added lipid, or diets containing OO or HVO (n = 5 cows/group) for 63 days. SAT was obtained from the tail-head area at the onset of the study and after 21, 42, and 63 days of supplementation. Treatments had minor effects on expression of measured genes. Both fat supplements reduced expression of PPARG, HVO decreased transcription of the desaturase FADS2 and lipid droplet formation PLIN2, and OO increased transcription of FABP3. Both lipid treatments decreased expression of the transcription regulator SREBF1 and its chaperone (SCAP) during the first 21 days of treatment. Our data indicated that long-term feeding of OO and HVO have a relatively mild effect on expression of lipogenic genes in SAT of mid-lactating cows.