A disposable, portable electrochemical immunosensor for rapid in situ detection of bovine tuberculosis.

This contribution describes the development of a simple, fast, cost-effective, and sensitive impedimetric immunosensor for quantifying bovine tuberculosis (TB) in bovine serum samples. The construction of the immunosensor involved immobilizing the purified protein derivative (PPD) of M. bovis onto a screen-printed electrode that was modified with gold nanoparticles (AuNPs) and a polypyrrole (pPy) film synthesized electrochemically. The immunosensor exhibited a linear range from 0.5 µg mL-1 to 100 µg mL-1 and achieved a limit of detection (LD) of 100 ng mL-1 for the detection of anti-M. bovis antibody. The recovery percentages obtained in bovine serum samples were excellent, ranging between 98 % and 103 %. This device presents several advantages over alternative methods for determining TB in bovine serum samples. These include direct, in situ measurement without the need for pre-treatment, utilization of small volumes, thus avoiding harmful solvents and expensive reagents, and portability. In addition, the immunosensor exhibits both physical and chemical stability, retaining effectiveness even after 30 days of modification. This allows simultaneous incubations and facilitates large-scale detection. Hence, this immunosensor presents itself as a promising diagnostic tool for detecting anti-M. bovis antibodies in bovine serum. It serves as a viable alternative to tuberculin and ELISA tests.

Comparative study of the oligosaccharide profile in goat, bovine, sheep, and human milk whey.

Milk oligosaccharides are high added value compounds that could be obtained by exploiting cheese whey, a byproduct of dairy industry. The objective was to compare the abundance and diversity of oligosaccharides in whey samples from domestic animals and humans. During fresh cheese making, whey samples were collected and analyzed by untargeted and targeted small molecule analysis using high-resolution mass-spectrometry. A great similarity in the metabolite profile between goat and sheep was observed. Up to 11 oligosaccharides were observed in the sheep whey from those typically found in humans. The concentration of 2'-Fucosyllactose (0.136 ± 0.055 g/L) and 3-Fucosyllactose (0.079 ± 0.009 g/L) were significantly higher (p-value <0.01) in sheep whey, while the concentration of 3'-Sialyllactose (0.826 ± 0.638 g/L) was higher in goat whey. No significant differences were observed between goat and sheep whey for the other oligosaccharides (p-value >0.05). Therefore, sheep and goat whey could become an important source of oligosaccharides through their revalorization.

Occurrence of Babesia and Anaplasma in ruminants from the Catimbau National Park, Semiarid Region of Northeast Brazil.

Babesiosis and Anaplasmosis are diseases associated with economic losses; ticks and blood-sucking flies are important zoonotic vectors and reservoirs. This study aimed to investigate the presence of anti-Babesia spp. and anti-Anaplasma marginale antibodies using enzyme-linked immunosorbent assay (ELISA), in ruminants at the Catimbau National Park. Blood samples were collected from 119 sheep, 119 goats, and 47 cattle. Rhipicephalus microplus ticks were collected from cattle. ELISA showed seropositivity of 34% (16/47), 20.3% (24/119), and 16% (19/119) for anti-Babesia bovis; 34% (16/47), 15.2% (18/119), and 9% (7/119) for anti-Babesia bigemina; and 34% (16/47), 35.6% (42/119), and 17% (20/119) for anti-A. marginale antibodies in cattle, goats, and sheep, respectively. The information collected using an epidemiological questionnaire showed that mostly are breed in a semi-intensive system, with access to Caatinga vegetation. The circulation of B. bovis, B. bigemina, and A. marginale was confirmed. Thus, based on the prevalence, this suggests this is an enzootic instability area and is prone to outbreaks.

Linseed oil supplementation alters milk fatty acid profile, mitigates heat stress, and improves summer milk yield in grazing dairy cows.

Dietary supplementation of fat can be an important source of energy to compensate for the reduction in dry matter intake in dairy cows during heat stress periods. Studies have reported that supplementing dairy cow diets with linseed oil (LO) can increase milk yield and enhance the levels of beneficial fatty acids, such as omega-3 fatty acids, in the milk. The objective of this research was to evaluate the effect of LO supplementation on milk fatty acids profile, milk yield and composition, and physiological parameters of grazing cows. The study was conducted in two seasons, one in spring and one in summer. A 2 × 2 Latin square design was used in each experiment. Twelve Holstein and crossbred Holstein x Jersey cows were involved in each season. Cows were divided into two groups: control (TC) with no supplementation and treatment (TL) supplemented with 400 g/day of LO. The results showed that LO supplementation altered the milk fatty acid profile: decreased concentrations of short and medium-chain fatty acids (C10:0 - C17:1) except for C13:0 and increased concentrations of long-chain fatty acids (C18, C18:1 (both trans and cis isomers), C18:2 (specific conjugated linoleic acid - CLA isomers), and C18:3 n3 (omega-3)). Additionally, milk yield increased by 1.5 l per day during summer in LO-supplemented cows, while milk fat, protein, and casein content decreased. Milk stability increased by 2.2% in the LO-supplemented group. LO-supplemented cows reduced internal body temperature and heart frequency in the afternoon and increased daily rumination time by 20 min. In conclusion, LO supplementation can be an effective strategy to improve the nutritional profile of milk by altering fatty acid composition towards potentially healthier fats, mitigate the negative effects of heat stress on grazing cows during summer, as evidenced by reduced body temperature and heart frequency and increase milk yield.

Effect of the Application of PGF2α Associated With Ovulation Induction in a Fixed-Time Superovulation Programme for Precocious Nellore Heifers.

This study evaluated the effect of prostaglandin F2α (PGF2α) associated with gonadotropin-releasing hormone (GnRH) for ovulation induction in precocious indicus heifers submitted to a fixed-time superovulation (SOV) programme. Precocious Nellore heifers (n = 35), aged 13 months, were subjected to the SOV protocol. On day 0 (D0), all animals received intravaginal insertion of a progesterone (P4) device along with intramuscular administration of 2 mg of oestradiol benzoate, plus 200 IU of follicle-stimulating hormone in decreasing doses, with 12-h intervals between D4 and D7, in addition to 150 µg of D-cloprostenol on D6 and device removal on D7. On D8, the donors received 10.5 µg of buserelin acetate and the treatment group received 300 µg of D-cloprostenol/PGF2α. Artificial insemination was performed 12 h and 24 h after GnRH administration using frozen semen. On D15 of the protocol (i.e., D7 after insemination), the embryos were collected and evaluated. All animals passed through the control and treatment groups. Results were evaluated by analysis of variance using an adjusted mixed-effects model (p < 0.05). There was no difference in the total number of embryos between the control and treatment groups (10.40 ± 1.52 vs. 9.60 ± 1.36; p = 0.63) or viable embryos (6.30 ± 1.22 vs. 4.30 ± 0.71). For precocious indicus heifers, treatment with PGF2α in association with GnRH did not affect embryo production in the fixed-time SOV protocol.

Efficient Method for Liposome-Based Gene Transfer in Cattle Embryos.

In vitro embryo production (IVP) in cattle is crucial for advancing genetic enhancement and preserving valuable genetic lineages, enabling precise genetic modifications and gene studies through modern techniques. Successful genetic manipulation in cattle embryos requires efficient delivery of exogenous DNA/RNA molecules. This research investigates the efficacy of a single embryo culture system for developing genetically modified zona-free (ZF) embryos and examines the use of liposome-based SAMTOR target siRNA transfer in these individually cultured ZF embryos. The findings indicated that the individual culture system resulted in increased cleavage rates, and blastocyst rates were minimally impacted. The new culture system effectively achieved SAMTOR silencing, with 8-16 cell embryos exhibiting reduction in transcript levels compared to control. Measurement of total protein content in the spent culture media was performed to validate the single-culture approach for further analytical applications. Total protein content analysis demonstrated the system's suitability for comprehensive evaluation of the embryo-media interaction, enhancing the scope for in-depth genetic research and applications. This research sheds light into an innovative method to improve genetic editing techniques in reproduction research.

Unveiling the hidden threat: investigating gastrointestinal parasites and their costly impact on slaughtered livestock.

This study investigated the prevalence of gastrointestinal (GI) parasites in ruminants slaughtered at the abattoir in district Narowal, Punjab, Pakistan. The overall prevalence of parasitic infection was determined to be 72.92% based on faecal examination. Among the ruminant species, goats exhibited a significantly higher (P < 0.05) prevalence of parasitic infection (78.63%) compared to cattle, buffalo, and sheep. Additionally, female ruminants showed a significantly higher (P<0.05) prevalence of infection (85.62%) compared to males (65.13%). The intestines (both small and large) of small and large ruminants were found to be significantly more affected, with a prevalence of 39.58% of parasitic infection compared to other examined organs. A total of ten parasitic genera were identified in ruminants, including hydatid cysts. Ruminants with a high burden of parasites (45.74%) significantly outnumbered those with light (23.40%) and moderate (30.85%) burdens. Economically, the estimated annual losses in Pakistan due to organ condemnation with GI parasites were substantial, amounting to Pak. Rs. 405.09/- million (USD = 1,428,760). These findings underscore the significance of GI parasite infections as a major animal health concern and a cause of significant economic losses in the research area.

Development of an indirect ELISA for the serologic detection of bovine viral diarrhea virus based on E2 antigen sub-genotypes 1b, 1e, and 1d.

Bovine viral diarrhea virus (BVDV) causes ongoing economic losses to cattle industries, directly through reduced herd performance or indirectly through control program costs. ELISA assays, one of the most widely used techniques due to their ease of implementation, have been a valuable tool for mass surveillance and detection of BVDV. In this study, we developed a new indirect ELISA (rE2-ELISA) for serologic detection of BVDV. The assay considers three recombinant E2 protein subtypes as antigens, allowing serologic diagnosis of BVDV-1b (high prevalence worldwide), BVDV-1d and 1e (high prevalence in southern Chile) sub-genotypes. Recombinant E2 (rE2) proteins were successfully expressed in stably transfected CHO cells. Conditions for rE2 ELISAs were established after determining appropriate concentrations of antigen, blocking agent, secondary antibody, and serum dilutions to achieve maximum discrimination between positive and negative serum samples. The developed rE2-ELISA showed a sensitivity of 92.86% and a specificity of 98.33%. Clinical testing of 180 serum samples from herds in southern Chile showed high accuracy (kappa > 0.8) compared to the commercial BVDV Total Ab kit (IDEXX), with 95.37% positive and 87.5% negative predictive value. In addition, the rE2 ELISA has shown the capability to detect anti-BVDV antibodies from naturally infected animals with sub-genotypes 1b, 1e, or undetermined. These results indicate that the developed indirect ELISA could serve as a valid, and efficient alternative for identifying BVDV-infected animals, thus contributing to the success of disease control and eradication programs.

Residual feed intake and gain alters the performance and carcass traits in Nellore cattle.

The residual intake and gain (RIG) aims to select animals that present low feed intake in relation to the expected. This study aimed to evaluate the associations of selection for RIG with performance and carcass traits in Nellore cattle. Initially, residual feed intake (RFI) and residual gain (RG) were determined. From this, the RIG was calculated, and the animals were classified as efficient and inefficient for RIG. The efficient animals for RIG showed higher daily weight gain (DWG), Longissimus muscle area (LMA), and mid-test metabolic body weight (MMBW) than the inefficient ones. No significant correlations were found between subcutaneous fat thickness (SFT), marbling (MAR), LMA, MMBW, and the RIG. Thus, it's concluded that the RIG is a measure that can be used to identify and select animals with higher rates of DWG and LMA without changes in the dry matter intake (DMI), SFT, and MAR. However, this index should still be observed with caution, as it may be dependent on body size. Based on the findings, the selection of animals according to the RIG can be an important factor to generate phenotypic evolution in characteristics such as weight gain and rib eye area without adverse effects on the carcass fat deposition.

Effect of replacing ground corn with cactus pear Nopalea cochenillifera (L.) on feed intake and digestibility, water intake, milk production and composition in Holstein × Gyr cows.

The objective of this study was to evaluate the intake and digestibility of nutrients, production and composition of milk, and water intake of lactating dairy cows fed standard diets in which ground corn (C) was replaced by up to 100% in the diet by cactus pear (CP). Eight Girolando cows (½ Gyr x ½ Holstein), 3rd calf multiparous, with 60 to 80 days of lactation and an average weight of 450.0 ± 30.0 kg, were randomly distributed in a double Latin square (4 × 4). Four experimental diets were evaluated: (100% C + 0% CP), (66.6% C + 33.3% CP), (33.3% C + 66.6% CP), and (0% C + 100% CP). There was a difference (P < 0.05) in the intake of CP and EE (kg.day- 1), with a quadratic effect and a linear reduction, respectively, with substitution. The maximum CP intake of 3.05 kg.day- 1 was found at 46.07% and EE intake fell by 3.81 g for each percentage unit of cactus pear added to the diet. There was a quadratic difference (P < 0.05) for DM intake in %BW and g.kg BW0,75, with maximum values of 3.97%BW and 186.8 g.kg BW0,75 with the substitution of 54.83 and 53.17%, respectively. There was a quadratic effect (P < 0.05) for the intake of NDF in %BW, with the maximum intake of 1.3% at the 74.69% substitution level. There was a linear reduction (P < 0.05) in the digestibility of DM, NDF, and TDN, and for the other nutrients there was no substitution effect (P > 0.05). There was no difference (P > 0.05) in milk production and composition. There was a linear reduction (P < 0.05) in water intake. Cactus pear can be used in a promising way to replace ground corn up to 100% in the diet of lactating dairy cows.

Assessment of inbreeding coefficients and inbreeding depression on complex traits from genomic and pedigree data in Nelore cattle.

BACKGROUND: Nelore cattle play a key role in tropical production systems due to their resilience to harsh conditions, such as heat stress and seasonally poor nutrition. Monitoring their genetic diversity is essential to manage the negative impacts of inbreeding. Traditionally, inbreeding and inbreeding depression are assessed by pedigree-based coefficients (F), but recently, genetic markers have been preferred for their precision in capturing the inbreeding level and identifying animals at risk of reduced productive and reproductive performance. Hence, we compared the inbreeding and inbreeding depression for productive and reproductive performance traits in Nelore cattle using different inbreeding coefficient estimation methods from pedigree information (FPed), the genomic relationship matrix (FGRM), runs of homozygosity (FROH) of different lengths (> 1 Mb (genome), between 1 and 2 Mb - FROH 1-2; 2-4 Mb FROH 2-4 or > 8 Mb FROH >8) and excess homozygosity (FSNP). RESULTS: The correlation between FPed and FROH was lower when the latter was based on shorter segments (r = 0.15 with FROH 1-2, r = 0.20 with FROH 2-4 and r = 0.28 with FROH 4-8). Meanwhile, the FPed had a moderate correlation with FSNP (r = 0.47) and high correlation with FROH >8 (r = 0.58) and FROH-genome (r = 0.60). The FROH-genome was highly correlated with inbreeding based on FROH>8 (r = 0.93) and FSNP (r = 0.88). The FGRM exhibited a high correlation with FROH-genome (r = 0.55) and FROH >8 (r = 0.51) and a lower correlation with other inbreeding estimators varying from 0.30 for FROH 2-4 to 0.37 for FROH 1-2. Increased levels of inbreeding had a negative impact on the productive and reproductive performance of Nelore cattle. The unfavorable inbreeding effect on productive and reproductive traits ranged from 0.12 to 0.51 for FPed, 0.19-0.59 for FGRM, 0.21-0.58 for FROH-genome, and 0.19-0.54 for FSNP per 1% of inbreeding scaled on the percentage of the mean. When scaling the linear regression coefficients on the standard deviation, the unfavorable inbreeding effect varied from 0.43 to 1.56% for FPed, 0.49-1.97% for FGRM, 0.34-2.2% for FROH-genome, and 0.50-1.62% for FSNP per 1% of inbreeding. The impact of the homozygous segments on reproductive and performance traits varied based on the chromosomes. This shows that specific homozygous chromosome segments can be signs of positive selection due to their beneficial effects on the traits. CONCLUSIONS: The low correlation observed between FPed and genomic-based inbreeding estimates suggests that the presence of animals with one unknown parent (sire or dam) in the pedigree does not account for ancient inbreeding. The ROH hotspots surround genes related to reproduction, growth, meat quality, and adaptation to environmental stress. Inbreeding depression has adverse effects on productive and reproductive traits in Nelore cattle, particularly on age at puberty in young bulls and heifer calving at 30 months, as well as on scrotal circumference and body weight when scaled on the standard deviation of the trait.

Unraveling the role of sperm retained histones in bull fertility and daughter fertility.

During spermatogenesis, a substantial proportion of histones are substituted by protamine to condense the genome within the sperm head. Studies indicate that a minority of histones, typically ranging from 1 to 15 %, persist in mammalian sperm post-substitution. The persistence of histones in the zygote facilitates chromatin accessibility to transcription factors in regions crucial for early embryonic development. Nevertheless, the potential causal relationship between retained histones and fertility phenotypes remains uncertain. This study seeks to investigate this relationship. The results indicate that in mature bovine sperm, regions of DNA associated with fertility that bind to histones are primarily concentrated in promoters and transcription start sites, potentially impacting bull fertility and offspring fertility through the regulation of relevant genes. Furthermore, microRNAs and estradiol/ESR are suggested to be the main regulators of the canonical pathways identified, highlighting the need for additional research to investigate their potential utility as biomarkers.

Cloning, characterization and functional analysis of lichenase produced by Bacillus licheniformis RB16 isolated from cattle faeces.

Lichenan, 1,3-1,4-ß-Glucan, a linear polysaccharide exists in the cell walls of various cereals, has garnered attention for its industrial applications due to its enzymatic breakdown by lichenase enzymes. In this study, Bacillus licheniformis strain RB16, isolated from cattle faeces, was identified as a robust lichenase producer. The lichenase gene, licA, was successfully cloned and characterized. The cloned RB16 lichenase (LicA) demonstrated its highest activity level at pH 7.5. It also retained over 50% of its activity within the pH range of 6.0-8.5 but experienced a decline to 40% at pH 9.0. LicA was active at temperatures ranging from 25 to 65 °C with an optimum at 45 °C. LicA exhibited more than 60% of its activity at the temperature range of 35-55 °C. Zymogram analysis confirmed LicA's lichenan-degrading ability and structural analysis revealed a stable enzyme structure primarily composed of random coils and extended strands. Although LicA exhibited low thermostability, consistent with its relatively low α-helix content, it demonstrated promising industrial potential. Evolutionary analysis placed LicA within a cluster of closely related Bacillus lichenases, particularly B. halotolerans, B. atrophaeus, and B. spizizenii. These findings expand our understanding of lichenases of Bacillus and underscore its potential for various industrial applications.

Comparative analysis of methods for monitoring the condition of small cattle using modern technologies.

For successful animal husbandry, farmers need to monitor the health status of animals on a daily basis, as well as ensure the safety and protection of animals. In this regard, the problem of choosing the optimal system for monitoring the condition of farm animals in the modern market is urgent. The practical value of the scientific article is to analyze the problems of stakeholders and, based on the needs, conduct a comparative analysis of various modern systems for monitoring the condition of small cattle using the weighted sum method. The object of the study was the process of monitoring the condition of small cattle using RFID tags, as well as the ability to monitor their health depending on the chosen approach. The subject of the study was a livestock enterprise that raises small cattle. It was found that the health of small cattle directly affects the financial stability of the farm. In the presented study, the authors analyze the problems of stakeholders and, based on the needs of stakeholders, conduct a comparative analysis of various modern systems for monitoring the condition of small cattle using the weighted sum method. The results obtained will help farmers make informed decisions in the future when choosing the most appropriate monitoring option for more effective and high-quality monitoring of the condition of small cattle, thereby reducing the risk of diseases and increasing profits for companies.

Predictive models for heat stress assessment in Holstein dairy heifers using infrared thermography and machine learning.

Heat stress is a condition that impairs the animal's productive and reproductive performance, and can be monitored by physiological and environmental variables, including body surface temperature, through infrared thermography. The objective of this work is to develop computational models for classification of heat stress from respiratory rate variable in dairy cattle using infrared thermography. The database used for the construction of the models was obtained from 10 weaned heifers, housed in a climate chamber with temperature control, and submitted to thermal comfort and heat wave treatments. Physiological and environmental data were collected, as well as thermographic images. The machine learning modeling environment used was IBM Watson, IBM's cognitive computing services platform, which has several data processing and mining tools. Classifier models for heat stress were evaluated using the confusion matrix metrics and compared to the traditional method based on Temperature and Humidity Index. The best accuracy obtained for classification of the heat stress level was 86.8%, which is comparable to previous works. The authors conclude that it was possible to develop accurate and practical models for real-time monitoring of dairy cattle heat stress.

Assessment of tooth discoloration induced by root canal filling materials in pediatric dentistry.

This study investigated the potential for tooth discoloration of root canal filling pastes used in pediatric dentistry. Sixty bovine incisors were sectioned 2 mm apical to the cementoenamel junction and allocated into 6 groups (n = 10) according to the type of filling material used: G1- Zinc oxide-eugenol sealer; G2- Zinc oxide-eugenol and iodoform paste; G3- Calcium hydroxide (CH) and zinc oxide paste; G4- CH, zinc oxide, and iodoform paste; G5- CH and iodoform paste; and G6- Control. Polyethylene glycol 400 was used as a vehicle for CH-containing pastes. Color measurements were taken at specific intervals: preceding endodontic treatment (T0) and at successive points of 1 month (T1), 2 months (T2), 3 months (T3), and 1 year (T4) after the placement of the filling material. The color change (∆E) was calculated using the CIELab formula. Statistical analysis was performed using ANOVA, followed by Tukey's post hoc test (α = 5%). Significant differences were observed among the filling materials and time intervals (p <0.001). All groups exhibited color changes over time, except G1 and G5, which showed color changes only after 1 year. G1 and G2 demonstrated the highest ∆E values, with a statistically significant difference observed only at T2 when compared to G3 (p = 0.008). Root canal filling materials used in primary teeth have the potential to induce tooth discoloration.

Dictyocaulosis in cattle: Retrospective analysis of 20 outbreaks in Central Argentina.

Bovine lungworms (Dictyocaulus viviparus) are nematodes which cause a respiratory disease known as verminous bronchitis or pneumonia. In this paper, we describe 20 outbreaks of bovine dictyocaulosis recorded between 2000 and 2023 in Central Argentina. Outbreaks occurred more frequently during the autumn-winter season (from April to August) and affected cattle under 1 year old in beef production systems. An average morbidity and mortality of 26.22 % and 8.44 % were registered, respectively. The main clinical signs observed were respiratory distress (coughing, tachypnea, dyspnea, and nasal discharge), weight loss, weakness, decubitus, and diarrhea. Necropsies were performed in thirty-one calves, heifers, and steers. Gross findings included diffuse interstitial or multifocal pneumonia, with marbled appearance intermingling atelectasis and red-gray firm areas of consolidation, and subpleural and interlobular emphysema and edema. Microscopically, lungs were characterized by abundant edema and mixed intra-alveolar multifocal to coalescent infiltrate. Frequently, adult worms and/or larvae were spotted in the bronchi or alveoli, respectively. Some cases exhibited proliferation of type 2 pneumocytes and hyaline membranes covering the alveolar septa. Co-infections with gastrointestinal nematodes were frequently found in fecal samples. Given the perspective of anthelmintic resistance and future changes in environmental conditions due to climate change, integrated parasitic control strategies are mandatory and should be tailored to each production system. The information gathered in this research provides an overview of lungworm infections in livestock production systems from Central Argentina and could be useful for surveilling, monitoring and designing strategic interventions for the control of this important parasitic disease in the region.

Exploring the biological responses involved in the genetic resistance to Rhipicephalus microplus in Argentine Creole cattle.

The common cattle tick Rhipicephalus microplus causes severe limitations to livestock production. Bovine genetics could be a decisive component for the success or failure of control programs for ticks and diseases transmitted. The objective of this work was to detect chromosomal regions associated with host resistance to R. microplus through an associative mapping study using medium and high density microarrays in a population of Argentine Creole cattle. The phenotypic record of the number of ticks that completed their development on the host, after artificial infestations, was obtained during 2015 to 2020. Genomic DNA was extracted for genotyping from 192 animals using Affymetrix high (Axiom™ Bos 1) and medium density (ArBos1) microarrays. In an exploratory study, chromosomal regions containing putative quantitative trait loci (QTLs) were recognized on chromosomes 27, 11, 10, 9, 16, 13, 3, 19, 8 and 18, associated with the variation of R. microplus load. Gene ontology based on genes located on these regions revealed an enrichment of terms and pathways for the immune system, blood coagulation, tissue regeneration, endopeptidase activity and protein phosphorylation. The information obtained in this work constitutes a first report of QTLs for tick count in the Argentine Creole cattle, and contributes with the knowledge about the underlying process involved in tick resistance.

Productive performance and carcass characteristics of castrated and non-castrated Beefalo-Nellore beef cattle finished in a feedlot or kept on pasture.

Beefalo is a fertile hybrid descendant of domestic cattle (Bos taurus) and American buffalo (Bison bison). Crossbred (¾Beefalo»Nellore) beef cattle raised and finished in a feedlot or on pasture were evaluated for the effect of two ages (8 and 13 months) at castration on nutrient intake, performance, and carcass characteristics. In the feedlot, they received a total diet with a roughage:concentrate ratio of 55:45, and those kept on Brachiaria decumbens pastures were supplemented at 0.8% of body weight (BW) with the same concentrate based on corn and soybean meal (17.8% CP and 73% TDN). Thirty-six crossbred (¾ Beefalo » Nellore) beef cattle with 209.2 ± 14.6 kg BW were used, which at weaning, at 8 months of age, were randomly divided into two groups, one of them destined to the feedlot system and the other group to the supplementation system on pasture. In each system (feedlot and pasture) the following treatments were distributed: castration at 8 months (at weaning, C8), castration at 13 months (C13), and non-castrated (NC), with six animals per treatment by system. All animals were slaughtered at 18 months of age. There was no significant interaction between the systems and castration ages for all variables studied. The averages of slaughter weight of feedlot animals were 475.6; 494.3 and 510.7 kg; and finished in pasture were 424.3; 428.0 and 418.7 kg for C8, C13, and NC treatments, respectively. The average subcutaneous fat thickness of the feedlot steers were 4.5, 3.5, and 1.3 mm, and for pasture-finished steers were 2.4, 1.6, and 1.8 mm for C8, C13, and NC treatments, respectively. Non-castrated animals have greater performance and carcass characteristics than castrated animals independent of the finished system. Animals non-castrated finished on Brachiaria grass pastures and slaughtered at 18 months of age require more intensive feeding management or even greater age at slaughter to obtain an ideal carcass finishing despite castration.

Co-doped titanium dioxide nanoparticles decrease the cytotoxicity of experimental hydrogen peroxide gels for in-office tooth bleaching.

OBJECTIVE: To evaluate the efficacy and cytotoxicity of experimental 6% and 35% hydrogen peroxide gels (HP6 or HP35) incorporated with titanium dioxide nanoparticles (NP) co-doped with nitrogen and fluorine and irradiated with a violet LED light (LT). METHODS: Bovine enamel-dentin disks adapted to artificial pulp chambers were randomly assigned to bleaching (n = 8/group): NC (negative control), NP, HP6, HP6 + LT, HP6 + NP, HP6 + NP + LT, HP35, HP35 + LT, HP35 + NP, HP35 + NP + LT, and commercial HP35 (COM). Color (ΔE00) and whiteness index (ΔWID) changes were measured before and 14 days after bleaching. The extracts (culture medium + diffused gel components) collected after the first session were applied to odontoblast-like MDPC-23 cells, which were assessed concerning their viability, oxidative stress, and morphology. The amount of HP diffused through the disks was determined. Data were analyzed by generalized linear models or Kruskal Wallis Tests (α = 5%).  RESULTS: HP6 + NP + LT exhibited ΔE00 and ΔWID higher than HP6 (p < 0.05) and similar to all HP35 groups. HP6 + NP + LT showed the lowest HP diffusion, and the highest cell viability (%) among bleached groups, preserving cell morphology and number of living cells similar to NC and NP. HP6 + LT, HP6 + NP, and HP6 + NP + LT exhibited the lowest cell oxidative stress among bleached groups (p < 0.05). HP35, HP35 + LT, and HP35 (COM) displayed the lowest cell viability. CONCLUSION: HP6 achieved significantly higher color and whiteness index changes when incorporated with nanoparticles and light-irradiated and caused lower cytotoxicity than HP35 gels. The nanoparticles significantly increased cell viability and reduced the hydrogen peroxide diffusion and oxidative stress, regardless of HP concentration. CLINICAL SIGNIFICANCE: Incorporation of co-doped titanium dioxide nanoparticles combined with violet irradiation within the HP6 gel could promote a higher perceivable and acceptable efficacy than HP6 alone, potentially reaching the optimal esthetic outcomes rendered by HP35. This approach also holds the promise of reducing cytotoxic damages and, consequently, tooth sensitivity.