Resumo

Bovine mastitis is the most impacting disease of dairy industry, and it is characterized by a complexity of causal agents, which have revealed a geographical variation among regions and countries. The mastitis-related pathogens have been traditionally classified as contagious or environmental, based on habits of the microorganisms and transmission routes. Besides, the severity of mammary infections has been associated with the virulence of the pathogens, and immune and nutritional status of the hosts. Considering this scenario, we investigated the etiological pattern, clinical severity scores, and days in milk (DIM) data in 4,273 clinical cases of bovine mastitis among ten large-dairy farms located in Brazil. Streptococcus dysgalactiae (283/4,273 = 6.6%), Escherichia coli (190/4,273 = 4.4%), Prototheca spp. (112/4,273 = 2.6%), and Streptococcus uberis (95/4,273 = 2.2%) were the predominant pathogens isolated. Among 4,273 clinical cases, clinical severity score was available in 43.8% (1,871/4,273) animals. From these, 69.8% (1,306/1,871), 27.3% (510/1,871), and 2.9% (55/1,871) were scored as mild, moderate, and severe, respectively. Pathogens were observed mainly in samples obtained during the first 100 days in milk, and clinical severity scored mainly as mild. Our results contributed to the etiological identification, clinical severity scoring, and milking aspects of mastitic cows in dairy farms with a history of clinical mammary infections.

A mastite bovina é a doença mais impactante na indústria de laticínios e é caracterizada por uma complexidade de agentes causais, os quais têm revelado uma variação geográfica entre regiões e países. Os patógenos relacionados à mastite têm sido tradicionalmente classificados como contagiosos ou ambientais, com base na fonte de infecção ou origem e nas vias de transmissão. Além disso, a gravidade das infecções mamárias tem sido associada à virulência dos patógenos, e ao estado imunológico e nutricional dos animais. Considerando esse cenário, investigamos os agentes etiológicos, os escores de gravidade clínica e os dados de dias em lactação (DEL) em 4.273 casos clínicos de mastite bovina em dez fazendas de grande porte, quatro localizadas no sudoeste do estado de São Paulo e seis no sul do Estado de Minas Gerais, Brasil. Streptococcus dysgalactiae (283/4.273 = 6,6%), Escherichia coli (190/4.273 = 4,4%), Prototheca spp. (112/4.273 = 2,6%) e Streptococcus uberis (95/4.273 = 2,2%) foram os patógenos predominantes isolados. Entre os 4.273 casos clínicos, a pontuação de gravidade clínica estava disponível em 43,8% (1.871/4.273) dos animais. Desses, 69,8% (1.306/1.871), 27,3% (510/1.871) e 2,9% (55/1.871) foram classificados como leves, moderados e graves, respectivamente. Os patógenos foram observados principalmente em amostras obtidas durante os primeiros 100 dias em lactação, e a gravidade clínica foi principalmente classificada como leve. Nossos resultados contribuem para a identificação etiológica, a pontuação de gravidade clínica e os aspectos de ordenha de vacas com mastite em fazendas leiteiras com histórico de infecções mamárias clínicas.

Resumo

The main transmission route of bovine coronavirus (BCoV) is direct contact with secretions and feces, and potentially also via contaminated surfaces. Following PRISMA guidelines, a systematic review was conducted to evaluate the presence of BCoV on environmental surfaces. A literature search, conducted between March and April 2023, utilized databases including Web of Science, PubMed, Scopus, Science Direct, and Springer. The review adhered to the PEO structure: Population - environmental surfaces; Exposure - contact with BCoV; Outcome - identification of presence or infectivity. Primary data were recorded using an extraction form organizing methods for detecting BCoV presence, assessing BCoV infectivity, types of surfaces evaluated, and study type. Search terms "Bovine coronavirus" and "BCoV" yielded 2703 articles. After removing 964 duplicates and excluding 1546 articles not mentioning BCoV in titles, 193 studies underwent abstract reading. Following exclusion criteria not addressing BCoV presence in the environment, three articles were selected for comprehensive review. These articles identified BCoV presence on various types of surfaces, with detection possible up to 81 hours after contamination, depending on surface type. Despite limited studies on BCoV presence on surfaces, findings suggested potential transmission via contaminated surfaces due to the virus's ability to remain infectious for up to 24 hours on fomites. This review underscores the need for further research on BCoV persistence in farm environments, an area currently lacking focused studies.

A principal via de transmissão do coronavírus bovino (BCoV) é o contato direto com secreções e fezes, podendo ocorrer também por meio de superfícies contaminadas. Uma revisão sistemática, seguindo as recomendações PRISMA, foi realizada para avaliar a presença de BCoV em superfícies ambientais. A busca na literatura foi realizada em março e abril de 2023 e as bases de dados utilizadas foram Web of Science, PubMed, Scopus, Science Direct e Springer. A revisão sistemática seguiu a estrutura PEO: População - superfícies ambientais; Exposição - contato com BCoV; Resultado - identificação da presença ou infectividade de BCoV. As informações primárias foram registradas por meio de um formulário de extração, organizando métodos para detectar a presença de BCoV, avaliar a infectividade de BCoV, tipos de superfícies avaliadas e tipo de estudo. Os termos de pesquisa "coronavírus bovino" e "BCoV" resultaram em 2703 artigos. Após remover 964 duplicatas e excluir 1546 artigos que não mencionavam o BCoV nos títulos, 193 estudos foram submetidos à leitura de resumos. Seguindo os critérios de exclusão, que não abordavam a presença do BCoV no ambiente, três artigos foram selecionados para revisão abrangente. Nestes artigos foi identificada a presença de BCoV em vários tipos de superfícies, sendo possível a detecção até 81 horas após a contaminação, dependendo do tipo de superfície. Apesar do número limitado de estudos que investigam a presença de BCoV em superfícies, os resultados sugerem o potencial de transmissão de BCoV por meio de superfícies contaminadas, devido à capacidade do vírus permanecer infeccioso por até 24 horas em fômites. Esta revisão destaca a necessidade de mais pesquisas sobre a persistência de BCoV em locais de criação de bovinos, uma área atualmente carente de estudos específicos.

Resumo

Bovine viral diarrhea virus (BVDV) is a productive and reproductive virus with a high global economic impact on dairy production systems. We investigated the prevalence of BVDV at the herd and individual levels in most dairy-producing regions of Brazil. The frequency of BVDV at the herd level was investigated using quantitative reverse transcription polymerase chain reaction (RT-qPCR) in bulk milk tanks monitored at 289 dairy farms between August 2020 and January 2022. Among these farms, 68 production systems were selected to investigate the prevalence of persistently infected (PI) animals using two antigen-enzyme-linked immunosorbent assays (Ag-ELISAs), at 21-d intervals, from ear-notch samples. In total, 2,902 RT-qPCR and 23,466 Ag-ELISAs were performed. At the herd level, 23.87% (69/289) of dairy farms were considered infected, presenting at least one qPCR test positive. At the individual level, 41.2% (28/68) of the subgroup of selected farms had at least one animal positive in the Ag-ELISA test. Association between tests allowed the classification of farms into the following four categories: level 0, negative for both tests (41.2%, 28/68); level 1, RT-qPCR positive and Ag-ELISA negative (17.6%, 12/68); level 2, RT-qPCR negative and Ag-ELISA positive (13.2%, 9/68); and level 3, positive for both tests (27.9%, 19/68). Multiple correspondence analysis (MCA) suggested a possible association between BVDV positivity and large farms, average daily milk production (herd), breed, and somatic cell counts. The confinement and intensification of animals from different categories, and use of artificial bedding are associated with BVDV infection. Using waste or bulk tank milk to fed calves was also a risk factor for BVDV positivity in RT-qPCR and Ag-ELISA. Despite the use of reproductive vaccines by most producers, their use seems to be associated with BVDV-positive farms. This study presented the epidemiological frequencies of BVDV at the individual and herd levels in the Campos Gerais Paranaense region. The region ranks among the top milk-producing areas in Brazil. Additionally, the association between BVDV tests and farm characteristics indicated the farm risk for BVDV and guides specific control programs.

O vírus da diarreia viral bovina (BVDV) é um vírus que afeta a produção e reprodução com alto impacto econômico global nos sistemas de produção de leite. Nosso objetivo foi investigar a prevalência do BVDV em rebanhos e indivíduos na região de maior produção de leite do Brasil. A frequência do BVDV nos rebanhos foi investigada usando reação em cadeia da polimerase com transcrição reversa quantitativa (RT-qPCR) em tanques de leite em 289 fazendas leiteiras, monitoradas entre agosto de 2020 e janeiro de 2022. Dentre esses rebanhos, 68 sistemas de produção foram selecionados para investigar a prevalência de animais persistentemente infectados (PI) usando dois testes imunoenzimáticos para a detecção do antígeno (Ag-ELISAs), em intervalos de 21 dias, a partir de amostras de tecido auricular. No total, foram realizados 2.902 RT-qPCR e 23.466 Ag-ELISAs. Na investigação dos rebanhos, 23,9% (69/289) das propriedades leiteiras foram consideradas infectadas, apresentando pelo menos um teste qPCR positivo. Na pesquisa de animais Pis, 41,2% (28/68) das fazendas selecionadas tiveram pelo menos um animal positivo no teste Ag-ELISA. A associação entre os testes permitiu classificar as propriedades em quatro categorias: nível 0, negativo para ambos os testes (41,2%, 28/68); nível 1, RT-qPCR positivo e Ag-ELISA negativo (17,6%, 12/68); nível 2, RT-qPCR negativo e Ag-ELISA positivo (13,23%, 9/68); e nível 3, positivo para ambos os testes (27,9%, 19/68). A análise de correspondência múltipla (MCA) sugeriu associação entre positividade para BVDV e grandes propriedades, produção média diária de leite do rebanho, raça e contagem de células somáticas. O confinamento e a intensificação de animais de diferentes categorias e o uso de camas artificiais estão associados à infecção pelo BVDV. O uso de leite residual ou a granel também foi um fator de risco para positividade para BVDV em RT-qPCR e Ag-ELISA. Apesar da utilização de vacinas reprodutivas pela maioria dos produtores, a sua utilização parece estar associada a explorações positivas para BVDV. Este estudo apresenta as frequências epidemiológicas do BVDV nos rebanhos e indivíduos de rebanhos da região dos Campos Gerais Paranaense. A região está entre as principais áreas produtoras de leite do Brasil. Além disso, a associação entre os testes de BVDV e as características da fazenda indica o risco da fazenda para o BVDV e orienta programas de controle específicos.

Resumo

Echinacea angustifolia is a perennial plant that has been traditionally used to treat various microbial diseases. This study evaluated the in vitro antiviral properties of an ethanolic extract of E. angustifolia against bovine alphaherpesvirus 1 (BoHV-1). BoHV-1 infection is associated with respiratory, reproductive and neurological disease in cattle, resulting in major economic losses. When cells were treated with E. angustifolia extract at a non-cytotoxic concentration at different times (3, 6 or 24 hours) before BoHV-1 inoculation, no viral detection was possible after 72h, while in untreated cells the virus reached a titer of 105.5TCID50 /25µl (median). Incubating the extract with BoHV-1 24 hours before cell inoculation did not result in loss of viral infectivity. Cells infected with 103 TCID50 of BoHV-1 and not treated with E. angustifolia showed an average of 45.8% viability after 48 hours of infection, while 91.1% remained viable when treated 6 hours after or 84.1% 24 hours after infection, demonstrating a significant reduction in the cytopathic effect. In addition, E. angustifolia significantly reduced the relative mRNA expression of the antiviral cytokines IFNα and IFNß in the treated cells, suggesting that the antiviral activity is not due to immunomodulation. The obtained data indicated that the ethanolic extract of E. angustifolia may directly interfere with virus attachment, entry, and/or egress from infected cells. Taken together, the presented data emphasized the promising antiviral activity of E. angustifolia against BoHV-1.

Echinacea angustifolia é uma planta perene que vem sendo utilizada para tratar diversas enfermidades de origem microbiana. Neste estudo foram avaliadas propriedades antivirais, in vitro, de um extrato etanólico de E. angustifolia frente ao alphaherpesvírus bovino 1 (BoHV-1). BoHV-1 causa enfermidades que afetam principalmente o trato respiratório e genital de bovinos, e que resultam em grandes perdas econômicas. Quando células foram tratadas com o extrato de E. angustifolia em concentração não citotóxica em diferentes tempos (3, 6, ou 24h) antes da inoculação do BoHV-1, não foi possível detectar o vírus por até 72 horas após, enquanto que nas células não tratadas o vírus alcançou o título de 105.5TCID50/25µl (média). A incubação do extrato com BoHV-1 24 horas antes da inoculação celular não resultou em inativação da infectividade viral. Células infectadas com 103 TCID50 de BoHV-1 não tratadas com E. angustifolia apresentaram em média 45,8% de viabilidade após 48 horas da infecção, enquanto que 91,1% permaneceram viáveis quando tratadas após 6 horas ou 84,1% após 24 horas da infecção, demonstrando uma significativa redução no desenvolvimento de efeito citopático. Além disso, E. angustifolia reduziu significativamente a expressão relativa de mRNA das citocinas antivirais IFNα e IFNß nas células tratadas, sugerindo que a atividade antiviral não ocorre devido a imunomodulação. E. angustifolia reduziu significativamente a expressão relativa de mRNA das citocinas antivirais IFNα e IFNß nas células tratadas, indicando que a atividade antiviral não ocorre devido a imunomodulação. Os dados obtidos indicam que o extrato etanólico da E. angustifolia pode interferir com a adsorção, penetração e/ou o egresso viral das células infectadas. Tomados em conjunto, os dados apresentados enfatizam uma promissora atividade antiviral da E. angustifolia contra o BoHV-1.

Resumo

The study aimed to evaluate the combined use of ultrasound (US) and incorporation of micronized salt (MS) as a strategy for reducing sodium without affecting the quality of beef burgers. Ten treatments were manufactured with varying MS content (0.75 %, 1.0 %, and 1.5 %) and ultrasound time (0, 5, and 10 min), with a control treatment manufactured at 1.5 % of regular salt without ultrasound. The beef burgers formulated with 0.75 % MS submitted to the US for 10 min (M0.75US10) reduced the salt content by 50 %, thereby efficiently maintaining texture profile (hardness, springiness, cohesiveness, and chewiness) and decreasing the cooking loss and diameter reduction compared to the control treatment. M0.75US10 treatment also preserved the color of samples after cooking, keeping myoglobin stable. Therefore, micronized salt coupled with ultrasound technology reduces sodium chloride content in beef burgers, enabling the application of clean technology to reduce sodium content in meat products efficiently.

Resumo

The objective of this review was to identify, synthesize, and characterize, through an integrative approach, the main beef cattle finishing systems used in Brazilian scientific research. A review protocol was developed, and the search terms were based on the PVO strategy to formulate the study's guiding question: study population (P) consists of beef cattle, the variables of interest (V) were the finishing systems adopted in the studies with cattle in Brazil, and the outcomes (O) were the characteristics of the finishing systems. The following guiding question was formulated: What are the major beef cattle finishing systems used in scientific research in Brazil? The databases used were SCOPUS, Web of Science, and Science Direct. 1,388 studies were found, 1,163 of which were scientific articles. However, 33 publications were selected for data extraction. The studies covered different regions of Brazil: Southeast (14), South (10), Midwest (8) and Northeast (1). The confinement finishing system was the strategy used in 63.4% of the experiments and 24.2% of pasture systems with supplementation. In 81.1% of the studies, the pure Nellore breed or crossed with other breeds was used. Scientific research on cattle finishing in Brazil focuses on confinement systems.

O objetivo desta revisão foi identificar, sintetizar e caracterizar, por meio de uma abordagem integrativa, os principais sistemas de terminação de bovinos de corte utilizados na pesquisa científica brasileira. Foi elaborado um protocolo de revisão, e os termos de busca foram baseados na estratégia PVO para formulação da questão norteadora do estudo: a população do estudo (P) é constituída por bovinos de corte, as variáveis de interesse (V) foram os sistemas de terminação adotados nos estudos com bovinos no Brasil, e os resultados (O) foram as características dos sistemas de terminação. Formulou-se a seguinte questão norteadora: Quais os principais sistemas de terminação de bovinos de corte utilizados em pesquisas científicas no Brasil? As bases de dados utilizadas foram SCOPUS, Web of Science e Science Direct. Foram encontrados 1.388 estudos, sendo 1.163 artigos científicos. Contudo, foram selecionadas 33 publicações para extração de dados. Os estudos abrangeram diferentes regiões do Brasil: Sudeste (14), Sul (10), Centro-Oeste (8) e Nordeste (1). O sistema de terminação em confinamento foi a estratégia utilizada em 63,4% dos experimentos e em 24,2% dos sistemas de pastagem com suplementação. Em 81,1% dos estudos, foi utilizada a raça Nelore pura ou cruzada com outras raças. A pesquisa científica sobre terminação de bovinos no Brasil concentra-se em sistemas de confinamento.

Resumo

We evaluated the reproductive losses in three periods: period I ­ starting from the time the cows were exposed to the bulls to pregnancy diagnoses (PD, number of cows diagnosed as non-pregnant/total exposed cows × 100); period II ­ from the time of PD to calving (number of calving cows/number of cows diagnosed as pregnant × 100); and period III ­ from calving to weaning (number of weaned calves/number of calving cows × 100) in purebred Hereford (HH) and Angus (AA) cows and their crosses in beef cows under extensive production systems. Likewise, the effect of parity (nulliparous, primiparous, and multiparous) and the interaction between both factors were studied. A thirteen-year data set (2505 record) of an experimental breeding herd, maintained in an extensive production system based on natural grassland, was used. The dataset was under a complete diallel design between HH and AA breeds. Both the genetic group and parity of the cow affected the reproductive losses, but only in period I. No interaction was found. Purebred cows had higher reproductive losses than the crossbred cows, without differences between the purebred (HH and AA) or between the crossbred (AH and HA). The greatest losses were observed rather in primiparous than in nulliparous and multiparous cows without difference between the latter two. The use of crossbred cows in extensive production systems is an alternative to reduce reproductive losses and to increase calf harvest.(AU)

Resumo

We investigated the impact of weaning at 30, 75, and 180 days of age on performance, body measurements, and rumen development (using the ß-hydroxybutyrate biomarker) of beef calves until 190 days of age. A total of 64 Brangus calves were assigned to three treatments: hyper-early (W30), weaned at 32±0.89 days of age (n = 22, 10 males and 12 females); early (W75), weaned at 77±0.95 days of age (n = 20, 12 males and eight females); and conventional (W180), weaned at 183±0.82 days of age (n = 22, 13 males and nine females). Body weight (BW), average daily gain (ADG), ß-hydroxybutyrate (ßHBA), and morphometric measurements were evaluated. These variables were influenced by an interaction between treatment and days and were not affected by the sex of calves. The W30 calves experienced weight loss from 30 to 40 days of age compared with the W75 and W180 calves. Consequently, at day 75, W30 animals were lighter and had lower body length, thoracic circumference, withers height, and croup height compared with the W75 and W180 calves. However, no significant differences in BW were observed among treatments at 85 days of age. Additionally, W30 calves exhibited higher ADG and a moderate correlation with ßHBA levels. Weaning calves at 30 days of age may negatively affect their performance until the sixth week after weaning, but there is no impairment in performance at 190 days of age.(AU)

Resumo

Reports on thyroid carcinomas in bovines are scarce. An 18-year-old Nellore cow was referred to a veterinary hospital due to lateral recumbency lasting one day after falling on irregular terrain. The patient was clinically diagnosed with spinal cord injury. Necropsy and histopathology revealed a thyroid tubule papillary carcinoma. Immunohistochemical analysis revealed discrete positive cells for calcitonin, moderately positive cells for thyroid transcription factor 1 (TTF-1), and strongly positive cells for thyroglobulin in the thyroid gland. Thus, this report describes a case of a mixed tubule papillary carcinoma derived from both medullary and follicular cells in a Nellore cow.(AU)

Resumo

The objective was to explore publications on the effects of genotype × environment interaction (GEI) in livestock farming. The dataset used for this analysis came from the Web of Science (WOS) database, and the search was carried out from the first article identified in the WOS database until the search date (August 17, 2023). A set of minimum parameters was defined, and then the data was processed using the VOSviewer® software. To generate visual representations in VOSviewer, fractional counting was used, in which the contribution of each article is divided proportionally based on the number of co-authors. Consequently, if an article has three authors, the weight of each author is calculated as 1/3. Brazil and the United States lead research on GEI, while India, China, and Uruguay are emerging countries on the subject. The most cited journals on GEI include the Journal of Animal Science, Journal of Dairy Science, Animal, Livestock Science, Journal of Animal Breeding and Genetics, and Revista Brasileira de Zootecnia. In Brazil, the research groups are at the forefront of publications related to GEI. Ongoing climate changes over the years have likely led to further investigations into this matter. In the Brazilian context, research groups from the São Paulo State University (UNESP), College of Agricultural and Veterinary Sciences ­ Jaboticabal, and the Faculty of Veterinary Medicine and Animal Science at the University of São Paulo (FZEA/USP, Campus Pirassununga) have played a prominent role in advancing this area of study. Furthermore, our bibliometric analysis revealed future trends in GEI publications, including an increasing integration of genomic information into research.(AU)

Resumo

Single nucleotide polymorphisms are variations of a single nucleotide base pair and can be associated to phenotypic characteristics. This study aimed to determine the association of CAPN1 and CAST gene polymorphisms with the tenderness of Creole cattle meat from the Amazonas region, Peru. The texture profile (adhesiveness, cohesiveness, Warner-Bratzler shear force, elasticity, gumminess, and chewiness) of 100 animals was determined in 100 g of Longissimus dorsi et lumborum muscle. Allelic frequencies, genotypic frequencies, and Hardy-Weinberg equilibrium (HWE) of calpain (CAPN-316, CAPN-530) and calpastatin (CAST-2959) gene polymorphisms were studied. Allelic and genotypic frequencies were calculated, as well as the Hardy-Weinberg equilibrium with the Chi-square test. The texture profile of each group of samples corresponding to a polymorphism was compared with the Duncan's test and the t-test for independent samples (p < 0.05). Genotypic frequencies were 78 % GG and 22 % CC for CAPN-316; 68 % GG, 5 % GA, and 27 % AA for CAPN-530; and 74 % AA, 18 % AG, and 8 % GG for CAST-2959. The CAPN-316, CAPN-530, and CAST-2959 polymorphisms were not in Hardy-Weinberg equilibrium. The CC genotype of CAPN-316 marker influences meat tenderness on day 21 of meat aging. In contrast, the GG genotype of CAST-2959 marker affects meat tenderness at days 14 and 21 of meat aging concerning the other genotypes.

Resumo

This study evaluated the effects of housing in the last month of gestation on hoof health in postpartum dairy heifers. The hooves of the heifers were evaluated during functional claw trimming and lameness scoring at 30 days before the expected calving date, and only heifers without any hoof lesions and lameness were included in the study. The heifers were kept in cubicle housing systems with mats (MAT, n = 12), mattresses (MATR, n = 12) and solid concrete floors, and on a straw yard (SY, n = 12) without exposure to concrete during the last month of gestation. The effects of housing systems on hoof lesions and lameness were evaluated during functional claw trimming and locomotion scoring at 60 and 90 days in milk (DIM). The evaluation of hoof lesions with respect to the study group, time, and their interaction was performed with the general linear mixed model for repeated measures. All heifers displayed sole hemorrhages (SH), white-line hemorrhages (WLH), and heel horn erosion in the postpartum period, but none of the heifers displayed lameness. The mean SH severity score was significantly higher in groups MAT and MATR than in group SY (2.25, 1.92, 0.75, respectively) at 60 DIM, and significantly higher in group MAT than in groups MATR and SY (1.92, 0.92, 0.92, respectively) at 90 DIM. The mean WLH severity score was higher in group MAT than groups MATR and SY (1.92, 1.17, 0.92, respectively) at 60 DIM, and similar (0.83, 0.75, 0.50, respectively) at 90 DIM. Heel horn erosion did not differ in severity among the groups. Improving housing comfort during the last month of pregnancy significantly decreases the severity of postpartum SH and WLH.(AU)

Resumo

This study aimed to evaluate food additives for the replacement of monensinand virginiamycin in high-grain diets for cattle. A Latin square experimental design was adopted, represented by four treatments (functional oil, yeast, tannin and control monensin and virginiamycin) in four experimental periods, with four animals cannulated in the rumen. l The natural ruminal modulators fully replaced the ionophores monensin and virginiamycin in the concentrate. Being evaluated: ruminal pH, apparent digestibility and in situdegradability of dry matter. The results showed that the pH variation curve as a function of rumen fluid collection time was not significant (P<0.05) among the additives studied. The additives used to replace monensin and virginiamycin in crossbred cattle fed a diet of 70% concentrate and 30% roughage with fractionation five times a day, are efficient in maintaining rumen pH above 6.0. The additives did not affect digestibility of OM, CP, NDF, FDA and EE.The in situ degradability of the soluble and potentially degradable fractions was higher in the yeast and essential oil treatments, respectively.The additives evaluated are efficient in replacing monensin and virginiamycin.

Objetivou-se com o presente estudo avaliar aditivos alimentares em substituição a monensina mais virginiamicina em dietas de alto grão para bovinos. Foi adotado o delineamento experimental em quadrado latino, representado por quatro tratamentos (Óleo funcional, Levedura, Tanino e o controle monensina e virginiamicina) em quatro períodos experimentais, com quatro animais cânulados no rúmen. Os moduladores ruminais naturais substituíram integralmente os ionóforos monensina mais virginiamicina no concentrado. Sendo avaliados: pH ruminal, digestibilidade aparente e a degradabilidade in situda matéria seca. Os resultados mostraram que a curva de variação do pH em função do tempo de coleta de líquido ruminal não foi significativa (P<0,05) entre os aditivos estudados. Os aditivos utilizados em substituição a monensina mais virginiamicina para bovinos mestiços com dieta 70% concentrado e 30% volumoso com fracionamento cinco vezes ao dia, são eficientes na manutenção do pH ruminal acima de 6,0. Não diferindo os aditivos na digestibilidade aparente de MO, PB, FDN, FDA e EE. A degradabilidade in situ apresentou maiores valores para a fração solúvel e potencialmente degradável nos tratamentos com levedura e óleos essenciais, respectivamente. Sendo os aditivos avaliados eficientes na substituição a monensina e virginiamicina.

Resumo

Hemoparasite infections are a substantial challenge to agriculture,worldwide. Infected cattle suffer malnutrition, stunting, decreased milk production, and reproductive loss, which can result in great economic loss. The aim of this study was to characterize the predominant hemoparasites affecting cattle in Nicaragua, whose economy is largely dependent on agriculture, and define associated epidemiological factors. Blood from 68 bovines in the municipality of León were analyzed by microscopy and molecular techniques. PCR revealed Anaplasma marginalein 33.82% (IC 95%: 21.84-45.80), 19.11% (IC 95%: 9.03-29.19) of animals were infected with Babesiaspp, and 8.82% (95% CI: 1.34-16.30) were simultaneously co-infected with Babesiaspp and A. marginale. However, A. phagocytophilum, Leishmaniaspp., or Trypanosomaspp were not detected (0%, 95% CI: 0.0-5.20). A. marginale was more frequently detected in males (p=0.041) and calves (p=0.041). This is the first study to report the prevalence of hemoparasites in cattle using molecular diagnosis in western Nicaragua.

Agentes infecciosos chamados hemoparasitas destroem as hemácias em bovinos. O objetivo deste estudo foi detectar os principais hemoparasitas em bovinos no município de León, Nicarágua, e os fatores epidemiológicos associados à sua presença. Foram coletadas 68 amostras de sangue bovino em EDTA e realizada PCR a partir de uma amostra conglomerada selecionada para representar os bovinos do município de León. A análise de PCR revelou que 33,82% (IC 95%: 21,84-45,80) dos animais foram positivos para A. marginale, 19,11% (IC 95%: 9.03-29,19) dos animais estavam infectados com Babesia spp, 8,82% (95% de IC: 1,34-16,30) estavam infectados com Babesia spp. e A. marginale, no entanto, nenhum animal foi considerado positivo para A. phagocytophilum, Leishmania spp. ou Trypanosoma spp (0%, IC 95%: 0,0-5,20). A. marginale foi detectada com maior frequência em machos (p=0,041) e bezerros (p=0,041). Este é o primeiro estudo que relata a prevalência de hemoparasitas em bovinos, aplicando diagnóstico molecular no oeste da Nicarágua.

Resumo

Selection strategies are performed post-fertilization when the random combination of paternal and maternal genomes has already occurred. It would be greatly advantageous to eliminate meiotic uncertainty by selecting genetically superior gametes before fertilization. To achieve this goal, haploid embryonic cells and embryonic stem cell lineages could be derived, genotyped, and used to substitute gametes. On the paternal side, androgenetic development can be achieved by removing the maternal chromosomes from the oocyte before or after fertilization. We have shown that once developed into an embryo, haploid cells can be removed for genotyping and, if carrying the selected genome, be used to replace sperm at fertilization. A similar strategy can be used on the maternal side by activating the oocyte parthenogenetically and using some embryonic cells for genotyping while the remaining are used to produce diploid embryos by fertilization. Placed together, both androgenetic and parthenogenetic haploid cells that have been genotyped to identify optimal genomes can be used to produce offspring with predetermined genomes. Successes and problems in developing such a breeding platform to achieve this goal are described and discussed below.(AU)

Resumo

This study explored the migration of follicular fluid (FF)-derived extracellular vesicles (EVs) of the uterine environment to the bloodstream and their interaction with neutrophils in vivo and in vitro. For the in vivo experiment, six Nellore heifers (Bos indicus) received an intrauterine infusion seven days after ovulation with 1X PBS only (sham group; n=1), 1X PBS stained with lipophilic dye PKH26 (control group; n=2), or FF-derived EVs stained with PKH26 (treated group; n=3). Plasma was collected at 0, 10, 30, 60-, 180-, 360-, 720-, and 1440-min post-infusion to obtained EVs for analysis by nano flow cytometry. Labeled EVs were present in the bloodstream at 30- and 60-min post-infusion in the treatment group. Additionally, plasma derived-EVs from all groups were positive for Calcein-AM, Alix, Syntenin, and Calnexin, which confirm the presence of EVs. The second experiment utilized the plasma-derived EVs from the heifers from 30 and 60 min timepoints to evaluate if neutrophils can uptake EVs in vitro. As results, it was possible to observe the presence of labeled EVs in neutrophils treated with plasma derived-EVs from the treatment group. In summary, our results suggest that labeled EVs can migrate from the uterine environment rapidly and interact with circulating immune cells in bovine.(AU)

Resumo

This work aimed to compare the efficiency of two commercial recombinant bovine somatotropin (rbST) formulations on productive, metabolic, behavioral, and feeding parameters of mid-lactation Holstein cows. Eighteen secondiparous cows were randomly assigned to two groups to be treated with injectable rbST (rbST-Fast, Boostin ® , MSD Saúde Animal; and rbST-Slow, Lactotropin ® , Agener União Saúde Animal). Cows were rbST-treated during five cycles of 14 days each, totaling 70 days. Blood samples were collected thrice in each cycle to assess metabolic markers. Daily, automatic feeders and individual monitoring collars measured behavior and feed intake. Milk samples were collected weekly to evaluate milk composition and somatic cell count. The rbST-Fast group had higher milk production ( p = 0.03) and tended to present greater feed intake ( p = 0.07). In addition, animals treated with rbST-Fast had higher ( p < 0.01) concentrations of non-esterified fatty acids (NEFA) and tended ( p = 0.09) to have lower serum glucose values. As for the variation in body weight, cows treated with rbST-Fast lost approximately three times more weight ( p < 0.01) than rbST-Slow cows. Regarding milk components, cows from the rbST-Fast group produced milk with a higher lactose content ( p = 0.05). In conclusion, rbST-Fast treated cows produced more milk, had higher feed intake, and showed a higher degree of lipid mobilization, demonstrated through the higher body weight loss and higher NEFA concentrations.

Resumo

The objective of this study was to identify parameters, before the start of the breeding season, that affect the conception rate of precocious Nelore heifers through ultrasonographic ovarian evaluation and evaluation of weight and body condition score (BCS). A total of 407 heifers aged 404±69 days (≈14 months old), weighing 267.1±31.2 kg, and with mean BCS of 3.1±0.5, were used. Heifers were subjected to hormone treatment to induce cyclicity and, 30 days later, to a fixed-time artificial insemination (FTAI) program with three managements. Morphometric measurements of ovaries and ovarian structures were performed by transrectal ultrasonographic evaluation, as well as weighing and evaluation of BCS on D −30 and D0. Conception rate was evaluated 30 days after FTAI. The conception rate of heifers did not vary according to ovary diameter, weight, BCS, and age at first calving. However, heifers with the presence of follicle with a diameter > 6 mm at D −30 and D0 had a higher conception rate at the first FTAI. The presence of a dominant follicle greater than 6 mm at D −30 is an efficient complementary criterion to identify 14-month-old Nelore heifers with greater ability to conceive at the first FTAI before the breeding season. Antral follicle count performed on D −30 is not a good tool to predict fertility at the first FTAI, and the weight may not be a limiter to select heifers under good nutritional and health management.(AU)

Resumo

The objective of this study was to evaluate, through principal component analysis, the effect of different feedlot structures on climatic conditions, nutrient intake, and performance of Nellore bulls during the feeding period in the semi-arid region. Data from 225 non-castrated Nellore bulls with initial mean body weight (BW) of 294 ± 19 kg and age of 24 months were used. This was done in a completely randomized design with three feedlot structures (no shading, natural shade, and artificial shade with 50% light interception), resulting in 75 repetitions (each animal serving as an experimental unit). The feeding period for the animals in the feedlot was 107 days. The first two components explained 99.65 (no shade), 97.32 (artificial shade), and 99.89 (natural shade) of total data variation. The variables, namely the black globe temperature index (0.88), radiant heat load (0.96, 0.99, 0.76), black globe temperature (0.96), and hot carcass weight (0.64) exerted the greatest influence on the feedlot structures. Climatic and intake variables were identified as having the most significant impact on feedlot structures. Artificial shade with 50% light interception shade cloth positively contributes to the hot carcass weight of feedlot Nellore cattle.(AU)

Resumo

This study evaluated the probability of pregnancy and associated factors for two times artificial inseminations (AI), 8 or 10 hours after automated activity monitoring (AAM) alarm on the first postpartum AI of 1,054 Holstein dairy cows. The estrus was synchronized by prostaglandin or estradiol-progesterone program. Stepwise logistic regression was performed to analyze the probability of pregnancy, and associated factors (activity, estrus intensity, parity, peripartum health, retained placenta, postpartum vaginal discharge, and season). The highest pregnancy rates were obtained with multiparous animals, inseminated ten hours after the AAM alarm, in the fall or winter season, with a high activity peak and estrus intensity (P < 0.05). Peripartum diseases, retained placenta, and postpartum vaginal discharge negatively influenced the pregnancy rate, regardless of parity. Thus, the optimization of AAM models by including on-farm measures like parity, peripartum health history, and environmental conditions may favor the correct identification of estrus and improve the AAM alarm regarding the ideal moment for AI, increasing the reproductive performance in dairy cows.

O objetivo deste estudo foi avaliar a probabilidade de prenhez e fatores associados para dois horários de inseminação artificial (IA), oito ou 10 horas após o alarme de monitoramento automatizado de atividades (AAM), na primeira IA pós-parto em 1.054 vacas leiteiras da raça Holandês. O estro foi sincronizado por protocolos a base de prostaglandina ou estradiol-progesterona. Regressão logística stepwise foi realizada para analisar a probabilidade de prenhez e fatores associados (atividade, intensidade do estro, paridade, saúde no periparto, placenta retida, descarga vaginal pós-parto e estação do ano). As maiores taxas de prenhez foram obtidas em multíparas, inseminadas 10 horas após o alarme do AAM, no outono ou inverno, com pico de atividade elevado e intensidade de estro (P < 0,05). Doenças no periparto, placenta retida e descarga vaginal pós-parto influenciaram negativamente a taxa de prenhez, independentemente da paridade. Assim, a otimização dos modelos de AAM, incluindo medidas rotineiras da fazenda como paridade, histórico de saúde no periparto e condições ambientais, podem favorecer a identificação correta do estro e melhorar o alarme do AAM em relação ao momento ideal para a IA, aumentando o desempenho reprodutivo nas vacas leiteiras.