Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Green forages have high concentrations of β-carotene, but these can be reduced during storage, from levels of 300 ppm to 10 ppm at the end of winter. β-carotene concentrations in cows are affected by the productive cycle, where plasma concentrations decrease during the dry period, reaching their lowest point around day 4 or 6 postpartum; causing reproductive problems due to the possible affectation of progesterone levels. This study was carried out between August 2014 and December 2015 in San Pedro de Poás (Costa Rica), in a semi-stabled dairy. The effect of different sources of β-carotene on its concentrations in colostrum and blood, progesterone concentration, reproductive parameters and somatic cells in milk was evaluated. Eighteen dry cows were used for this study, separated into 3 groups (Control, parenteral β-carotene (T1) and enteral β-carotene (T2)). Plasma concentrations of β-carotene were affected during the productive cycle, being the lowest level just after calving (p<0.015). Enteral administration of β-carotene was only able to produce significant changes in blood concentrations of progesterone and β-carotene during the first 120 days postpartum, without significantly affecting the reproductive parameters of the evaluated cows or somatic cell counts.

The objective of this study was to determine the effect of the inclusion of Tithonia diversifolia on the physical, fermentative, and nutritional characteristics of Cuba OM22 grass with Musa sp. silage. The study was carried out between September 2020 and July 2021. An unrestricted, randomized design was used to mix Cuba OM22 grass and wild sunflower (Tithonia diversifolia) in percentage ratios of 0:100, 25:75, 50:50, 75:25, and 100:0. 10% of Musa sp. and 5% of molasses were added on a fresh basis to these previous mixtures. The silage was prepared in a 5 kg plastic bag of microsilos with hermetic closure for 60 days. T. diversifolia forage affected the physical characteristics of the silage, mainly color, and texture, while pH was not different between the treatments. The concentration of dry matter decreased as well as the neutral detergent fiber (NDF) and the digestible neutral detergent fiber (dFDN). On the other hand, T. diversifolia increased the contents of crude protein (PC) and non-fibrous carbohydrates (NFC). PC raises 0.5 percentage points, while NFC increases 4.25 percentage points, and NDF reduces at a rate of 5.0 points. In all cases, for each increase of 25% of T. diversifolia; those effects were reflected in the increase of the number of digestible nutrients on the silage. In conclusion, the inclusion of T. diversifolia, allowed to improve the nutritional quality of the silages, without affecting the fermentation process, although its physical quality could be affected due to the higher humidity of the shrub utilized.

Nitrogen fertilization of pastures is an agronomic practice used to increase forage´s yield. In this research, literature was reviewed in different countries of America with the objective of identifying the effect of inorganic and organic nitrogen (N) fertilization in different dosages on the production and quality of Cynodon´s grasses.  The information was analyzed by grouping the type of fertilizer and the doses of N. For inorganic fertilizers, dosage ranges from 25 to 400 kg N/ha per year were found. The information was related to the productive response of Cynodon´s grasses in terms of fresh and dry biomass production; dry matter (%DM); crude protein (%CP); neutral detergent fiber (%FDN); acid detergent fiber (%FDA) and in vitro digestibility of dry matter (%DIVMS). DM production was higher for organic fertilizers. CP was higher for nitrogen applications at doses greater than 201 kg N/ha and organic treatments. DM percentage was higher in N doses of 101-200 kg N/ha (27.4%). The FDA and NDF obtained lower values for N doses >201 kg N/ha (63.3% and 31.7%). The in vitro dry matter digestibility was higher in N doses of 25-100 kg N/ha. Fresh biomass production was higher in organic fertilizers (13 723 kg N/ha). Plant height had similar values in organic fertilizers and in N treatments of 25-100 kg N/ha (40,90 and 40,78 cm). Due to the diverse behavior of the productive, nutritional, and physiological variables presented in this review, producers should establish parameters based on system objectives, in order to choose doses and type of fertilizer that covers the needs of their pastures. 

Consumer concerns about animal welfare have prompted egg producers to dabble into alternative systems. This review aimed to describe the feeding practices and animal welfare of laying hens in systems with access to pastures, as well as forage management and production costs. Eighty-seven scientific manuscripts were consulted in databases and were classified according to feeding, behavior, characteristics of the grazing area, animal welfare, and costs. A free-range system has an area outside covered with vegetation where hens can spend at least 6 hours per day throughout the year, while weather conditions allow it. These systems need to control and manage environmental conditions, grazing areas, animal welfare, bird health, and operating costs, in which feeding reaches up to 41%, so producers want to replace part of this cost with forage, with the aggravating circumstance that an excess of forage causes malnutrition, affecting animal welfare and productive performance. Entrepreneurs of free-range egg production systems must know the proper management of birds and pastures, to manage the system to guarantee adequate nutrition, the manifestation of normal behaviors, and the absence of stress, fear, pain, and illness.

This study aimed to determine the nutritional characteristics of fresh and ensiled mixtures made from legumes and four carbohydrate sources. The experiment was carried out between 2015 and 2016. A random factorial design was used with combinations of four legume species (Vigna unguiculata, Arachis pintoi, Cratylia argentea, Erythrina poeppigiana) and 4 carbohydrate sources (sugar cane molasses, dehydrated citrus pulp, ground corn, and immature square banana fruit), for a total of 16 treatments. The forages were chopped and placed in vacuum-packed bags for 50 days. Artisanal bacterial inoculum (1 L/ton) was added to all treatments, with four repetitions. The bromatology of the silages was affected by the legume species and the carbohydrate source. Dry matter content of the silages was less than 23%, with tree silages having the highest average (19.9%) compared to herbaceous legumes (12.6%). The crude protein showed values between 13.9-19.4% in the different treatments. Non-fibrous carbohydrates had a concentration between 23.1-37.5%. Acid detergent fiber ranged between 21.6-38.2% and total digestible nutrients showed a range between 58.3-66.1%. Cratylia silages were the materials showing the greatest contribution of crude protein, due to their nutrient content, although they also showed the lowest energy content, regardless of the type of carbohydrate used. On the other hand, ground corn was the source of carbohydrates causing most of the changes in the silages, since it increased the values ​​of dry matter, non-fibrous carbohydrates, and energy.

The objective of this study was to describe and analyze the productive and economic performance of a commercial finishing cattle system under an intensive grazing scheme with strategic supplementation during the period between 2009 and 2016. The supplementation showed a positive impact when the bulls spend 183 days on the farm with a daily weight gain of 1,067 kg to 94 days with 1,871 kg; this reduction in farm increased the number of production cycles per year, from selling 112 animals in 2009 to 811 in 2016. Thus, the net profit per bull in 2009 increased from ₡31.410.19 to ₡52.618.33 in 2016. Finally, the profitability percentage was similar in the years evaluated, oscillating between 6% and 7%. It is concluded that strategic supplementation made a great improvement in the productive and economic performance of the production system.

This study evaluates the effect of curing modes and times on the mechanical properties of nanocomposites. Two nanocomposite resins were investigated: supra-nanohybrid (Estelite Posterior Quick; EP) and nanohybrid (Solare X; SX). They were polymerized with a light-emitting diode light-curing units (LED LCU, Valo) as follows: standard mode for 20s (ST20), high power mode for 12s (HP12), high power mode for 20s (HP20), extra power mode for 6s (XP6), and extra power mode for 20s (XP20). For Vickers microhardness (HV), disc-shaped specimens were fabricated (n=10). For the three-point bending test, bar-shaped specimens were fabricated (n=10). Flexural strength and resilience modulus were calculated. The fractured surfaces and specimen surfaces of composites were observed using scanning electron microscopy. The data were analyzed with repeated measures ANOVA, two-way variance, and Bonferroni tests (p<0.05). On the top and bottom surfaces of the EP nanocomposite resin, ST20 and HP12 revealed statistically higher HV than with XP6. Moreover, HP20 and XP20 had statistically higher HV than HP12 and XP6. For the SX nanocomposite resin, HP20 had statistically higher HV than HP12. For EP and SX, there were no significant differences in flexural strength and resilience modulus regarding the curing modes and times. Furthermore, SX demonstrated lower mechanical properties than EP. Scanning electron microscopy indicated that both nanocomposites had similar surface appearances. However, with all curing modes and times, SX exhibited layered fractures and more crack formations than EP. Different curing modes and times could influence the microhardness of nanocomposites.

A 3-dimensional (3D) printed custom-frame can improve the peripheral seal of readily available surgical/medical masks. This study aimed to assess the acceptance of a 3D-printed custom-frame with the American Society for Testing and Materials (ASTM) surgical/medical masks and the use of a face shield. A total of 206 subjects from a dental school participated, who answered a multiple-choice questionnaire. Participants received an invitation through the institutional email of the school via Qualtrics platform. 3D printed custom-frames were fabricated for each participant. According to their response, participants were divided into 4 groups: mask only (M), mask and frame (MF), mask and face shield (MFS), and all 3 personal protective equipment (MFFS). Data was analyzed in absolute and relative frequency. The acceptance of a 3D-printed custom-frame in the group MFFS varied between “poor”/’’very poor” (44.7%). It allowed “good” performance of routine procedures (40.3%), but “poor” visual quality (48.1%). Musculoskeletal tolerance and ease to perform movements were adequate. There was no interference in olfactory sensitivity (44.7%) or in the ability to breathe (34.5%). Finally, it showed "moderate pain" (48.1%) on the ear and "no pain" (38.9%) on the head. The 3D-printed custom-frame adapted to ASTM surgical/medical face masks showed reasonable tolerance.  Side effects of ear pain ranging in degrees were noted. Further research is indicated to evaluate safety, comfort, compliance, side effects, and occupational hazards of long-term use of enhanced PPE recommendations.Avoiding the recurrent outbreaks of COVID-19, the use of PPE by the public is necessary. Improper PPE use is a major source of concern for human and environmental health. Preventing such activities can be done by following steps involved in PPE disposals or by getting a new way to re-use such as improving peripherical sealing. Our work highlights that a custom-frame can improve protection, without adverse effects.

This study aimed to evaluate the effectiveness of using an ionized monocalcium phosphate and enamelin derivatives (IMP+ED) based mouthwash for the treatment of dentin hypersensitivity (DH) after scaling and root planing (SRP). 47 patients who reported DH after SRP treatment were included in this prospective cohort study. The Schiff Cold Air Sensitivity Scale (SCASS) was applied to classify their degree of pain in mild, moderate or intense at two times: after SRP (T0), and after one month of using a IMP+ED-based mouthwash (T1). The McNemar-Bowker test was used to compare the correlated proportions between both times (p<0.05). After the SRP therapy (T0), all the sample members reported pain distributed in the following manner: 12.8% were mild, 27.6% moderate, and 59.6% intense. At one month since treatment and with the use of the IMP+ED-based mouthwash (T1), the distribution of pain levels changed to 83% mild, 12.8% moderate, and 4.3% intense, this change was statistically significant (p<0.001). IMP+ED-based mouthwash produces a positive effect in reducing painful responses caused by exposure of the dentin tubules to the oral environment after SRP therapy.

Temporomandibular joint dysfunction syndrome (TMD), is a collective term characterized by symptoms involving chewing muscles, temporomandibular joint and orofacial structures. The efficacy of low intensity laser (LLLT) Gallium arsenide, in combination with a non-steroidal anti-inflammatory drug (NSAID) was evaluated. The main objective was to evaluate the maximum mouth opening without pain (ABM), arthralgia in the joint capsule through visual analog scale (VAS), laterality, protrusion, joint noises and count of tablets ingested per group. A controlled clinical trial (double-blind-randomized) was carried out in 30 subjects, who presented DTM of arthrogenic etiology; 5 applications of LLLT were made with wavelength of 810 nm, output optical power of 100-200 mw, emission PW=Pulsed (1-10,000Hz), dose of 10 jouls-cm², time of 1.44 minutes in mouth closed and with the mouth half open. One more follow-up appointment per month. There were two groups: experimental and control group, where different variables were analyzed (ABM, laterality, protrusion, VAS and sociodemographic). In the control group, a supposed LT application (not active) was made, for later comparison. Pain-free ABM was assessed in all appointments in addition to the other clinical parameters. Repeated measures analysis was performed with mixed models. Thirty patients were included of which 28 finished the treatment, two of them were lost during follow-up. The groups were similar in all their baseline variables. There were no statistically significant differences when applying the final multiple regression analysis, in the ABM, or in any other of the clinical parameters analyzed. LT was not effective in treating arthrogenic DTM.