Impact of maternal protein supplementation during mid or late gestation on skeletal muscle energy metabolism of beef calves / Impacto da suplementação proteica materna durante o terço médio ou terço final da gestação sobre o metabolismo energético do tecido muscular de bezerros de corte

ABSTRACT: This study evaluated the effect of maternal protein supplementation during mid or late gestation on energy metabolism of the skeletal muscle of beef calves. Sixteen pregnant cows were divided into 3 groups: CTRL (not supplemented); MID (supplemented from 30 to 180 days of gestation); and LATE (supplemented from 181 to 281 days of gestation). The supplement contained 30% crude protein. Thirty days after birth, blood and muscle samples of the calves were collected for analyses of gene expression, proteins, and metabolites. No differences (P ≥ 0.15) in birth weight, performance at weaning, or muscle expression of the genes evaluated (P ≥ 0.21) were observed. Calves born to CTRL cows had a lower ratio (P = 0.03) of p-AMPK/AMPK protein in the skeletal muscle. Calves born to MID cows had lower (P = 0.04) glucose concentration than those born to LATE cows. Changes in p-AMPK/AMPK protein, indicated a possible metabolic inflexibility in the skeletal muscle of calves born to CTRL cows. These results indicated that lack of protein supplementation in pregnant cows alter the energy metabolism of their calves and reflect in a metabolic inflexibility.

RESUMO: O objetivo deste estudo foi avaliar o efeito da suplementação proteica materna sobre o metabolismo energético do músculo esquelético de bezerros de corte. Dezesseis matrizes gestantes foram divididas em três grupos: CONTROLE (não suplementado); MÉDIO (suplementados entre 30 e 180 dias de gestação); e FINAL (suplementado entre 181 e 281 dias de gestação). O suplemento continha 30% de proteína bruta e foi fornecido em quantidades totais iguais aos tratamentos. Trinta dias após o nascimento, amostras de sangue e músculo dos bezerros foram coletadas para análises de expressão gênica, abundância de proteínas e metabólitos. Não foram observadas diferenças (P ≥ 0,15) no peso ao nascimento ou parâmetros de desempenho ao desmame, bem como na expressão dos genes avaliados (P ≥ 0,21). Os bezerros nascidos de matrizes do tratamento CONTROLE apresentaram menor proporção (P = 0,03) de proteína p-AMPK/AMPK no músculo esquelético. Os bezerros nascidos de matrizes do tratamento MÉDIO apresentaram concentração de glicose menor (P = 0,04) do que aqueles nascidos de matrizes do tratamento FINAL. Os resultados observados indicam que a ausência de suplementação proteica em matrizes gestantes pode alterar o metabolismo energético da progênie e refletir em uma inflexibilidade metabólica, a qual pode ocasionar limitações quanto à eficiência energética do tecido muscular esquelético e consequentemente, limitar o desempenho da progênie ao longo da fase pós-natal.

A comparison of the economic results obtained by Holstein steer calves with different feedlot arrival body weights / Uma comparação dos resultados econômicos obtidos por bezerros Holstein com diferentes pesos vivos na entrada do confinamento

ABSTRACT: The study compared the economic results between five groups of Holstein steers with different arrival body weights (ABW) but similar ages in the feedlot. The average ABW were 105, 112, 117, 123 and 129 kg (30, 90, 87, 60, and 30 calves, respectively) with an age of 113 ± 1d. The calves were randomly distributed using an unbalanced design. The calves were weighed upon arrival at the feedlot and subsequently on days 112, 224, and 361 of the study. The calves were fed a steam- flaked corn-based diets. A receiving diet (2.21 Mcal of NEm/kg DM) was provided during the initial 112 days of feeding. From day 112 until harvest all steers received a finishing diet (2.27 Mcal of NEm/kg DM). Because two different diets were used, two partial (day 1 to day 112 and day 113 to day 361), and one full period (day1 to day 361) feeding periods were evaluated. Statistical differences between the final weights of all the groups were observed, which allowed a profit estimation, obtained by subtracting the purchase cost of calves plus the total feed cost from the revenue obtained from the sale of the steers. Overall weight gain and feed intake were higher with increased ABW, feeding efficiency was better for intermediate ABW groups (112 and 117 kg), with the calves with ABW of 112 kg being the most profitable (USD 15.8 more profit than the 117 Kg. group)

RESUMO: O estudo comparou os resultados econômicos entre cinco grupos de bezerros de raça holandesa com pesos vivos de chegada diferente, mas com idades semelhante em confinamento. Os pesos corporais médios de chegada foram 105, 112, 123 e 129 kg (30, 90, 87, 60 e 30 bezerros, respectivamente) com idade de 113 ± 1-d. Os bezerros foram distribuídos em um desenho não balanceado completamente aleatório. Os bezerros foram pesados da chegada ao confinamento e, posteriormente, nos dias 112, 22 e 361 do estudo. Os bezerros foram alimentados com dietas à base de milho floculado. A dieta de adaptação (2,21 Mcal de NEm / kg MS) foi fornecida durante os 112 dias iniciais de ração. Após 112 até o final do estudo todos os novilhos receberam a dieta de terminação (2,27 Mcal de NEm /kg MS). Diante do exposto, foram avaliados dois períodos parciais de alimentação e um período completo (1 a 112, 113 a 361 e 1 a 361 d, respectivamente). O lucro de cada grupo foi estimado subtraindo o custo de compra dos bezerros mais o custo total da alimentação da receita obtida com a venda dos novilhos. O ganho de peso geral e o consumo de ração aumentaram com o aumento do ABW, mas a eficiência alimentar foi melhor para os grupos intermediários ABW (112 e 117 kg), sendo os novilhos com ABW de 112 kg os mais lucrativos (USD 15, 8 a mais do que o grupo de 117 kg.)

A glycoprotein E gene-deleted bovine alphaherpesvirus 1 strain is attenuated and immunogenic for calves with passive immunity upon intranasal immunization / Cepa de alfaherpesvírus bovino 1 com deleção do gene da glicoproteína E é atenuada e imunogênica para bezerros com imunidade passiva após imunização intranasal

ABSTRACT: Vaccination has been used to prevent the losses associated with Bovine alphaherpesvirus 1 (BoHV-1) infection but passively acquired antibodies may compromise vaccine efficacy. Intranasal immunization (IN) of calves with modified live viral BoHV-1 vaccines has proven to overcome the acquired passive antibodies and confer adequate protection. Herein, we evaluated the safety and immunogenicity of a glycoprotein E-deleted Brazilian BoHV-1 strain (BoHV-1gEΔ) for IN immunization of calves. Ten 1-to-2 months-old calves with virus-neutralizing titers (VN) ranging from 2-64 were immunized IN with viable BoHV-1gEΔ (107.1 TCID50) and four remained as unvaccinated controls (VN titers 8-32). After IN immunization, calves presented a transient (2-6 days) mild nasal secretion and shed the vaccine virus in nasal secretions in low titers (<102.6TCID50/mL) for 4-8 days. Interestingly, the vaccinated calves did not show an increase in VN titers after vaccination. Rather, they presented a gradual reduction in serum VN antibodies in the following weeks - similarly to unvaccinated controls. Upon IN challenge with a virulent heterologous BoHV-1 strain at day 55 post-immunization (107.63TCID50), vaccinated calves shed significantly less virus from day 6 post-challenge onwards (p < 0.07) and for a shorter period of time than the controls (p < 0.0024). Importantly, both the duration and intensity of clinical signs were reduced in vaccinated animals. In addition, vaccinated calves showed an abrupt raise in VN titers post-challenge, indicating adequate immunological priming by vaccination. In summary, immunization of calves harboring passive antibodies with BoHV-1gEΔ by the IN route was able to prime the immunity to afford partial virological and clinical protection upon challenge.

RESUMO: A vacinação tem sido usada para prevenir perdas associadas à infecção pelo alfaherpesvírus bovino 1 (BoHV-1), embora anticorpos adquiridos passivamente possam comprometer a eficácia das vacinas. A imunização intranasal (IN) de bezerros com vacinas de BoHV-1 vivas modificadas pode contornar o obstáculo relacionado à presença de anticorpos adquiridos passivamente, conferindo proteção aos animais vacinados. Nesse contexto, avaliou-se a segurança e imunogenicidade de uma cepa brasileira de BoHV-1 com deleção no gene da glicoproteína E (BoHV-1gEΔ) na imunização IN de bezerros. Dez bezerros, de um a dois meses de idade e com títulos neutralizantes (VN) variando de 2-64, foram inoculados IN com BoHV-1gEΔ (107,1TCID50), e quatro permaneceram como controles não vacinados (títulos de VN 8-32). Após a instilação IN, os bezerros apresentaram secreção nasal transitória leve (2-6 dias) e excretaram o vírus vacinal nas secreções nasais em baixos títulos (<102,6TCID50/mL) por 4-8 dias. Interessantemente, os bezerros vacinados não apresentaram aumento nos títulos de anticorpos neutralizantes após a vacinação. Em vez disso, eles apresentaram uma redução gradual nos anticorpos neutralizantes séricos nas semanas seguintes - semelhante aos controles não vacinados. Após o desafio IN com uma cepa BoHV-1 virulenta heteróloga no dia 55 pós-imunização (107,63TCID50), os bezerros vacinados excretaram o vírus em títulos menores a partir do sexto dia pós-desafio (p < 0,07) e por um período de tempo menor do que o observado nos controles (p < 0,0024). É importante notar que tanto a duração quanto a intensidade dos sinais clínicos foram reduzidas nos animais vacinados. Além disso, os bezerros vacinados apresentaram um aumento abrupto nos títulos neutralizantes após o desafio, indicando uma imunização adequada por BoHV-1gEΔ. Em resumo, a imunização IN de bezerros com anticorpos passivos com a cepa BoHV-1gEΔ foi capaz de estimular a imunidade, proporcionando proteção virológica e clínica parciais após o desafio.

Impact of persistent bovine viral diarrhea virus infection on indicators of innate and adaptive immune function in holstein calves and cows / Impacto da infecção persistente pelo vírus da diarreia viral bovina sobre indicadoresde função imunológica inata e adaptativa em bezerras e vacas holandesas

ABSTRACT: We evaluated some indicators of innate and humoral immune response in persistently infected (PI) Holstein calves and cows from 1 to 36 months of age matched with controls from the same herd. The effects were cataloged by grouping animals into the following age groups: <12 months, 13 to 24 months, and 25 to 36 months of age. Blood samples were collected once from each animal to measure total serum protein, haptoglobin, and neutralizing antibodies titers induced by respiratory virus vaccination. Total serum protein (g/dL) was lowest in PI calves younger until 24 months old, while haptoglobin concentration was higher in PI cattle. The serum neutralizing titers against BVDV and BRSV were lower in all PI calves and cattle than in controls. PI cattle have a high serum concentration of haptoglobin, and its possible dysregulated innate immune response appears to impact the efficacy of their adaptative immune responses, resulting in poor vaccine responsiveness.

RESUMO: O objetivo desta pesquisa foi avaliar alguns indicadores da resposta imune inata e humoral em bezerros a vacas persistentemente infectadas, entre um a 36 meses de idade, pareados com controles oriundos de um mesmo rebanho. As variáveis respostas foram avaliadas agrupando-se os animais nos seguintes grupos etários: < 12 meses, 13 a 24 meses, 25 a 36 meses de idade. Amostras sanguíneas foram coletadas para mensurar as concentrações séricas de proteína, haptoglobina e anticorpos neutralizantes induzidos pela vacinação contra as viroses respiratórias. Os teores de proteína sérica total (g/dL) foram menores nos animais persistentemente infectados (PI) jovens até 24 meses de idade, enquanto que a concentração de haptoglobina foi maior nos animais PI mais velhos (25 a 36 meses). Os títulos de anticorpos neutralizantes contra o BVDV e BRSV foi menor nos animais PIs independentemente da idade, comparado com o grupo controle. Os valores reduzidos ou nulos de anticorpos contra as viroses respiratórias, combinado com a evidência de resposta imune inata desregulada, contribui com a susceptibilidade dos animais PIs para as infecções secundárias.

Effect of lactic acid bacteria preparations on calf fecal flora

This experiment was conducted to investigate the effects of lactic acid bacteria preparations on microbial diversity and community structure of calves. On days 1 and 7 of the trial period, feces were collected into sterile tubes and labeled (Day 1: control group D1DZ, experimental group D1SY, and Day 7: control group D7DZ, experimental group D7SY). Twenty Angus calves (150±10 kg) were selected and randomly divided into two groups of 10 calves each. The control group fed a basal diet. In addition to feeding the basal diet, the experimental group was given 15 mL lactobacillus preparation orally at 09:00 and 16:00 h every day. Calves were allowed free feeding and drinking water. All other feeding environments and management conditions remained consistent with the experiment lasting for seven days. At the end of the experiment, the fecal microflora of the calves was analyzed using 16S rRNA sequencing techniques. The 16S rRNA analysis data were processed using the Excel 2007 software and analyzed by the IBM SPSS statistical software (Statistical Analysis System, version 22). The Alpha diversity index analysis showed that the Chao and the Ace indices were significantly different after feeding supplemented with lactic acid bacteria. The PCA analysis showed that the fecal flora structure differed significantly after supplementation with the lactic acid bacteria preparation. Further analysis showed that the lactic acid bacteria increased Firmicutes, Patescibacteria, Rikenellaceae_RC9_gut_group, Clostridium_sensu_stricto_1, and prevotellaceae_UCG-003 in the feces. Therefore, we speculate that lactic acid bacteria preparations play an important role in animal production and are beneficial to the diversity of the fecal microflora of the calves.

Maternal instinct of imported meat direction cattle and ethology of their calves

The examination of maternal qualities in the ethology of cows and their young offspring, derived from the study on adaptability and productivity of second and third-generation Aberdeen Angus cattle imported to Kazakhstan from Canadian and European selection, is presented in this paper. The findings indicate that Canadian heifers, belonging to the second generation, displayed extended feeding behavior throughout the day, dedicating 33.2 minutes or 2.2% more time to feeding compared to their European counterparts (P < 0.001). Similar disparities between groups were observed in the duration of the ruminant process. Moreover, Canadian heifers consumed water for an additional 2 minutes or 0.6%, which can be attributed to their higher daily feed intake. The calving process of Aberdeen Angus cows generally proceeded smoothly, demonstrating a well-developed maternal instinct towards their offspring. Notably, calves born from Canadian cows exhibited greater agility and achieved the ability to stand on their feet in a shorter time, with an average duration of 41.0 ± 1.60 minutes, which was 11.7% faster than European calves. Additionally, Canadian calves displayed a shorter time to locate their mother's breast, with an average duration of 68.0 ± 7.70 minutes.(AU)

Fontes de dieta líquida no aleitamento artificial e seu impacto no desenvolvimento ponderal de bezerras leiteiras: revisão de literatura / Sources of liquid diet in artificial feeding and its impact on the ponderal development of dairy calves: literature review

A criação de bezerras é uma das atividades mais complexas em uma propriedade leiteira. Desde o nascimento, o desempenho máximo deve ser priorizado, pois o sucesso no aleitamento leva ao aumento do peso vivo ao desmame e à futura produção de leite. Existem diferentes formas de fornecer leite aos bezerros, e uma delas é o aleitamento artificial, onde os animais recebem a dieta líquida em baldes, mamadeiras ou recipientes semelhantes. Neste tipo de aleitamento, diferentes fontes de dieta líquida podem ser utilizadas como o leite integral, os sucedâneos lácteos e o leite não comercializável ou leite de descarte. Independentemente do método de aleitamento, a quantidade de leite a ser oferecida deverá atender às exigências do animal para melhor desempenho futuro. A presente revisão de literatura avaliou as diferentes fontes de dieta líquida empregadas no aleitamento artificial de bezerras e o seu impacto no desenvolvimento ponderal desses animais na fase de cria.(AU)

Raising calves is one of the most complex activities on a dairy farm. From birth, maximum performance should be prioritized, since successful breastfeeding leads to an increase in live weight at weaning and the future milk production. There are different ways for providing milk to calves, one of them is artificial feeding, where animals are fed the liquid diet in buckets, bottles, or similar. In this type of breastfeeding, there are several sources of liquid diet that could be applied as whole milk, dairy substitutes, and non-marketable milk or waste milk. Regardless of the breastfeeding method, the amount of milk to be offered must meet the requirements of the animal, for the best future performance. This literature review evaluated different sources of liquid diet in artificial feeding and its impact on the weight development of dairy calves in this rearing phase.(AU)

A comparison of the economic results obtained by Holstein steer calves with different feedlot arrival body weights / Uma comparação dos resultados econômicos obtidos por bezerros Holstein com diferentes pesos vivos na entrada do confinamento

The study compared the economic results between five groups of Holstein steers with different arrival body weights (ABW) but similar ages in the feedlot. The average ABW were 105, 112, 117, 123 and 129 kg (30, 90, 87, 60, and 30 calves, respectively) with an age of 113 ± 1d. The calves were randomly distributed using an unbalanced design. The calves were weighed upon arrival at the feedlot and subsequently on days 112, 224, and 361 of the study. The calves were fed a steam- flaked corn-based diets. A receiving diet (2.21 Mcal of NEm/kg DM) was provided during the initial 112 days of feeding. From day 112 until harvest all steers received a finishing diet (2.27 Mcal of NEm/kg DM). Because two different diets were used, two partial (day 1 to day 112 and day 113 to day 361), and one full period (day1 to day 361) feeding periods were evaluated. Statistical differences between the final weights of all the groups were observed, which allowed a profit estimation, obtained by subtracting the purchase cost of calves plus the total feed cost from the revenue obtained from the sale of the steers. Overall weight gain and feed intake were higher with increased ABW, feeding efficiency was better for intermediate ABW groups (112 and 117 kg), with the calves with ABW of 112 kg being the most profitable (USD 15.8 more profit than the 117 Kg. group)

O estudo comparou os resultados econômicos entre cinco grupos de bezerros de raça holandesa com pesos vivos de chegada diferente, mas com idades semelhante em confinamento. Os pesos corporais médios de chegada foram 105, 112, 123 e 129 kg (30, 90, 87, 60 e 30 bezerros, respectivamente) com idade de 113 ± 1-d. Os bezerros foram distribuídos em um desenho não balanceado completamente aleatório. Os bezerros foram pesados da chegada ao confinamento e, posteriormente, nos dias 112, 22 e 361 do estudo. Os bezerros foram alimentados com dietas à base de milho floculado. A dieta de adaptação (2,21 Mcal de NEm / kg MS) foi fornecida durante os 112 dias iniciais de ração. Após 112 até o final do estudo todos os novilhos receberam a dieta de terminação (2,27 Mcal de NEm /kg MS). Diante do exposto, foram avaliados dois períodos parciais de alimentação e um período completo (1 a 112, 113 a 361 e 1 a 361 d, respectivamente). O lucro de cada grupo foi estimado subtraindo o custo de compra dos bezerros mais o custo total da alimentação da receita obtida com a venda dos novilhos. O ganho de peso geral e o consumo de ração aumentaram com o aumento do ABW, mas a eficiência alimentar foi melhor para os grupos intermediários ABW (112 e 117 kg), sendo os novilhos com ABW de 112 kg os mais lucrativos (USD 15, 8 a mais do que o grupo de 117 kg.)

Calves with arthritis - changes in antioxidant parameters

Background: In a healthy organism, oxidants and antioxidants are in balance. However, in cases such as inflammation, infection, and stress, this balance is disrupted in favor of oxidants, creating oxidative stress that can cause damage to cells or tissues. It is known that oxidative stress plays a role in the pathogenesis of many diseases. Determination of oxidant and antioxidant balance, especially in inflammatory diseases, plays an important role in elucidating the pathogenesis of the disease and developing treatment strategies. This study, it was aimed to reveal the oxidant status in inflammatory disease of calves with septic and aseptic arthritis. Materials, Methods & Results: The material of the study consisted of 21 calves up to 2 months old, of different races and genders, 14 (9 male, 5 female) with arthritis and 7 healthy (control, 5 male, 2 female). Of the calves with arthritis, 11 were septic and 3 were acute aseptic. In the calves with arthritis, the affected joint or joints were determined by clinical examinations. By palpating the joints, swelling, local temperature increase, tension in the joint capsule, presence of pain, and the presence and severity of lameness were examined. The color, clarity, viscosity, odor, and clot formation of the synovial fluid were examined and determined to be septic or aseptic. To determine the antioxidant status, the levels of malondialdehyde (MDA), which is the most important oxidative stress marker, and superoxide dismutase (SOD), gluta-thione peroxidase (GSH-Px), and catalase (CAT), which are the enzymatic antioxidant enzymes, were measured spectro-photometrically in serum samples. Vitamin E, C, and A levels, which are nonenzymatic antioxidants, were also measured colorimetrically. In the clinical examination, lameness was detected in the relevant extremity of all patients with arthritis. In the macroscopic examination of the synovial fluids taken from animals with arthritis, the colors of the synovial fluids varied between yellow and yellow tones in 11 cases; in 3 cases, it was determined that they were red and brown. It was observed that the colors of the synovial fluids were transparent in the subjects in the control group. It was observed that the synovial fluid clarity of the calves with arthritis was lost, with severe turbidity (+++) in 3 cases, moderately turbid (++) in 6 cases, slightly turbid (+) in 2 cases, and clear (-) in 3 cases. It was observed that the viscosity of synovial fluid taken from calves with arthritis decreased in varying degrees according to the severity of the disease, severe (+++) in 5 cases, moderately decreased (++) in 4 cases, slightly decreased (+) in 2 cases, and normal in 3 cases. It was determined that the viscosity of the synovial fluid taken from the calves in the control group was normal. There was a statistically significant difference between the groups in terms of MDA (P < 0.01), SOD (P < 0.01), GSH-Px (P < 0.05), vitamin E (P < 0.001), and vitamin C (P < 0.01), while MDA levels increased in calves with arthritis, SOD and GSH-Px activities and vitamin E and C levels decreased significantly. Although there was no statistically significant difference in CAT (P > 0.05) enzyme activity, it was determined that it was at a lower level in calves with arthritis, and there was no significant difference be-tween the groups in terms of vitamin A (P > 0.05). Discussion: According to the results of the study, there is an increase in oxidative stress and a decrease in antioxidant status in calves with arthritis. It is thought that these changes may be due to efforts to reduce tissue damage by reducing lipid peroxidation. As a result, it was determined that oxidant and antioxidant balance was impaired in calves with arthritis, and oxidative stress and lipid peroxidation developed due to the increase in free radicals. It is thought that giving additional antioxidants to the calves may contribute to the recovery of the disease and reduce treatment costs.

A glycoprotein E gene-deleted bovine alphaherpesvirus 1 strain is attenuated and immunogenic for calves with passive immunity upon intranasal immunization / Cepa de alfaherpesvírus bovino 1 com deleção do gene da glicoproteína E é atenuada e imunogênica para bezerros com imunidade passiva após imunização intranasal

Vaccination has been used to prevent the losses associated with Bovine alphaherpesvirus 1 (BoHV-1) infection but passively acquired antibodies may compromise vaccine efficacy. Intranasal immunization (IN) of calves with modified live viral BoHV-1 vaccines has proven to overcome the acquired passive antibodies and confer adequate protection. Herein, we evaluated the safety and immunogenicity of a glycoprotein E-deleted Brazilian BoHV-1 strain (BoHV-1gEΔ) for IN immunization of calves. Ten 1-to-2 months-old calves with virus-neutralizing titers (VN) ranging from 2-64 were immunized IN with viable BoHV-1gEΔ (107.1 TCID50) and four remained as unvaccinated controls (VN titers 8-32). After IN immunization, calves presented a transient (2-6 days) mild nasal secretion and shed the vaccine virus in nasal secretions in low titers (<102.6TCID50/mL) for 4-8 days. Interestingly, the vaccinated calves did not show an increase in VN titers after vaccination. Rather, they presented a gradual reduction in serum VN antibodies in the following weeks - similarly to unvaccinated controls. Upon IN challenge with a virulent heterologous BoHV-1 strain at day 55 post-immunization (107.63TCID50), vaccinated calves shed significantly less virus from day 6 post-challenge onwards (p < 0.07) and for a shorter period of time than the controls (p < 0.0024). Importantly, both the duration and intensity of clinical signs were reduced in vaccinated animals. In addition, vaccinated calves showed an abrupt raise in VN titers post-challenge, indicating adequate immunological priming by vaccination. In summary, immunization of calves harboring passive antibodies with BoHV-1gEΔ by the IN route was able to prime the immunity to afford partial virological and clinical protection upon challenge.

A vacinação tem sido usada para prevenir perdas associadas à infecção pelo alfaherpesvírus bovino 1 (BoHV-1), embora anticorpos adquiridos passivamente possam comprometer a eficácia das vacinas. A imunização intranasal (IN) de bezerros com vacinas de BoHV-1 vivas modificadas pode contornar o obstáculo relacionado à presença de anticorpos adquiridos passivamente, conferindo proteção aos animais vacinados. Nesse contexto, avaliou-se a segurança e imunogenicidade de uma cepa brasileira de BoHV-1 com deleção no gene da glicoproteína E (BoHV-1gEΔ) na imunização IN de bezerros. Dez bezerros, de um a dois meses de idade e com títulos neutralizantes (VN) variando de 2-64, foram inoculados IN com BoHV-1gEΔ (107,1TCID50), e quatro permaneceram como controles não vacinados (títulos de VN 8-32). Após a instilação IN, os bezerros apresentaram secreção nasal transitória leve (2-6 dias) e excretaram o vírus vacinal nas secreções nasais em baixos títulos (<102,6TCID50/mL) por 4-8 dias. Interessantemente, os bezerros vacinados não apresentaram aumento nos títulos de anticorpos neutralizantes após a vacinação. Em vez disso, eles apresentaram uma redução gradual nos anticorpos neutralizantes séricos nas semanas seguintes - semelhante aos controles não vacinados. Após o desafio IN com uma cepa BoHV-1 virulenta heteróloga no dia 55 pós-imunização (107,63TCID50), os bezerros vacinados excretaram o vírus em títulos menores a partir do sexto dia pós-desafio (p < 0,07) e por um período de tempo menor do que o observado nos controles (p < 0,0024). É importante notar que tanto a duração quanto a intensidade dos sinais clínicos foram reduzidas nos animais vacinados. Além disso, os bezerros vacinados apresentaram um aumento abrupto nos títulos neutralizantes após o desafio, indicando uma imunização adequada por BoHV-1gEΔ. Em resumo, a imunização IN de bezerros com anticorpos passivos com a cepa BoHV-1gEΔ foi capaz de estimular a imunidade, proporcionando proteção virológica e clínica parciais após o desafio.

Impact of persistent bovine viral diarrhea virus infection on indicators of innate and adaptive immune function in holstein calves and cows / Impacto da infecção persistente pelo vírus da diarreia viral bovina sobre indicadores de função imunológica inata e adaptativa em bezerras e vacas holandesas

We evaluated some indicators of innate and humoral immune response in persistently infected (PI) Holstein calves and cows from 1 to 36 months of age matched with controls from the same herd. The effects were cataloged by grouping animals into the following age groups: <12 months, 13 to 24 months, and 25 to 36 months of age. Blood samples were collected once from each animal to measure total serum protein, haptoglobin, and neutralizing antibodies titers induced by respiratory virus vaccination. Total serum protein (g/dL) was lowest in PI calves younger until 24 months old, while haptoglobin concentration was higher in PI cattle. The serum neutralizing titers against BVDV and BRSV were lower in all PI calves and cattle than in controls. PI cattle have a high serum concentration of haptoglobin, and its possible dysregulated innate immune response appears to impact the efficacy of their adaptative immune responses, resulting in poor vaccine responsiveness.

O objetivo desta pesquisa foi avaliar alguns indicadores da resposta imune inata e humoral em bezerros a vacas persistentemente infectadas, entre um a 36 meses de idade, pareados com controles oriundos de um mesmo rebanho. As variáveis respostas foram avaliadas agrupando-se os animais nos seguintes grupos etários: < 12 meses, 13 a 24 meses, 25 a 36 meses de idade. Amostras sanguíneas foram coletadas para mensurar as concentrações séricas de proteína, haptoglobina e anticorpos neutralizantes induzidos pela vacinação contra as viroses respiratórias. Os teores de proteína sérica total (g/dL) foram menores nos animais persistentemente infectados (PI) jovens até 24 meses de idade, enquanto que a concentração de haptoglobina foi maior nos animais PI mais velhos (25 a 36 meses). Os títulos de anticorpos neutralizantes contra o BVDV e BRSV foi menor nos animais PIs independentemente da idade, comparado com o grupo controle. Os valores reduzidos ou nulos de anticorpos contra as viroses respiratórias, combinado com a evidência de resposta imune inata desregulada, contribui com a susceptibilidade dos animais PIs para as infecções secundárias.

Cow milk or milk replacer in the diet of Holstein calves: effects on complete blood count, biochemistry variables, and performance / Leite de vacaousucedâneo do leitenadieta de bezerrosholandeses: efeitos no hemogramacompleto, variáveis ​​bioquímicas e desempenho

This study aimed to evaluate whether feeding calves with replacers instead of cow's milk interferes with complete blood count, biochemistry variables, survival, and weight gain, and the cost-benefit of these feeds in the suckling phase. We used 16 calves of the Holstein breed with an average of 8±4 days and 39±6 kg of average body weight, randomly divided into two groups: Replacer Group (N=8), receiving four liters of replacer milk during the 60 experimental days; and the Milk Group (N=8), calves receiving four liters of cow's milk. We observed that animals fed with cow's milk had higher body weight and weight gain at all weightings compared to those who consumed the dairy replacer. There was no calve death during the study. The cost (R$) of the diet of the calves that consumed replacer was lower. However, if we consider the weight gain during the experiment, the cost to produce 1 kg of body weight was similar between the treatments, because the calves that consumed milk were weaned with an average of 19kg more body weight. In conclusion, the use of dairy replacers as a replacer for cow's milk caused calves to have an overall lower performance compared to those who received cow's milk during the suckling phase.(AU)

Este estudo teve como objetivo avaliar se a alimentação de bezerros com sucedâneoem substituição ao leite de vaca causa interferência no hemograma, variáveis bioquímicas, sobrevivência e ganho de peso e o custo-benefício desses alimentos na fase de aleitamento. Foram utilizados 16 bezerros da raça Holandesa com média de 8±4 dias e 39±6 kg de peso corporal médio, divididos aleatoriamente em dois grupos: Grupo Sucedâneo (N=8), recebendo quatro litros de leite em pó durante os 60 dias de experimentos; e o Grupo Leite (N=8), bezerros recebendo quatro litros de leite de vaca. Observamos que os animais alimentados com leite de vaca apresentaram maior peso corporal e ganho de peso em todas as pesagens em relação aos que consumiram o sucedâneo lácteo. Não houve morte de bezerros durante o estudo. O custo (R$) da dieta dos bezerros que consumiram substituto foi menor. No entanto, se considerarmos o ganho de peso durante o experimento, o custo para produzir 1 kg de peso corporal foi semelhante entre os tratamentos, pois os bezerros que consumiram leite foram desmamados com média de 19kg a mais de peso corporal. Em conclusão, o uso de sucedâneos lácteos como substituto do leite de vaca fez com que os bezerros tivessem um desempenho geral inferior em comparação com aqueles que receberam leite de vaca durante a fase de aleitamento.(AU)

Does the use of corn and soybean hulls affect calf performance in the preweaning period?

The objective of this study was to assess the effects of two levels of soybean hulls (0 and 400.1 g/kg) and whole or ground corn in the diet of newborn crossbred dairy male calves on intake, performance, blood indicators, and feeding cost. Twenty-eight calves with an average weight of 33.0±6.2 kg and four days of age were distributed into four treatment groups in a completely randomized design (n = 7) for 56 days. Weekly samples of feed, diets, and leftovers were collected to determine dry matter and nutrient intakes. To evaluate apparent digestibility, samples were taken using titanium dioxide as a maker. Blood samples were also collected to evaluate blood indicators. The inclusion of soybean hulls resulted in greater neutral detergent fiber intake by the calves, but reduced their non-fibrous carbohydrates intake, which was also reduced by the use of whole corn in the diet. Although the total digestible nutrients content of diets decreased with the use of whole corn and inclusion of soybean hulls, its intake did not vary (0.75 kg/d), regardless of the factors analyzed. The apparent digestibilities of dry matter (0.87 kg/kg) and crude protein (0.89 kg/kg) were similar, resulting in similar performance between the animals, regardless of the factors analyzed. In the quantities evaluated, the use of soybean hulls or whole corn did not affect blood indicators and was insufficient to reduce feed costs; the cost of daily feed was $2.06, while the cost per kilogram of gain was $3.74. The inclusion of up to 400.1 g/kg of soybean hulls or the replacement of ground corn with whole corn does not affect the performance of crossbred dairy calves during the preweaning period, demonstrating that both can be used in animal feed during this phase of production.(AU)

Effectiveness of oral electrolyte solutions with different compositions for the treatment of neonatal calves with induced osmotic diarrhea / Eficácia de soluções eletrolíticas orais com diferentes composições no tratamento de bezerros neonatos com diarreia osmótica induzida

In a randomized controlled trial, we evaluated the effects of five oral electrolyte solutions (OESS) with different compositions of water, electrolyte, and acid-base balances of diarrheal neonatal calves. Osmotic diarrhea and dehydration were induced with sucrose in milk, spironolactone, and hydrochlorothiazide for 48 h in thirty 10-day old Holstein healthy calves with 43.5 ± 3.80 kg BW who were fed with natural milk. They were allocated to five treatment groups (n=6) based on the administered OES (commercial: OES A, B, C, D; and non-commercial: OES UEL). On the day of treatment, the calves received 6L of OES in two doses apart from milk intakes. Venous blood samples were collected at -48h (start of induction), -24h, Oh (start of the treatment day), 8h, 16h, 24h, 48h, and 72h. TPP, glucose, D-lactate, L-lactate, pH, pCO2, HCO3, BE, Na, K, CI, SID3, SIG, AG, Atot and percentage change in plasma volume (%PV) were measured or calculated and analyzed by two-way repeated measures ANOVA. All the calves developed osmotic diarrhea, mild to moderate dehydration, hyponatremia, relative hyperchloremia, and moderate to severe metabolic acidosis. The tested OESS were well accepted by the calves and effective in reversing dehydration, electrolyte imbalances, and metabolic acidosis. OES D did not completely correct hyponatremia, and SEO B caused transient hyperglycemia. It has been concluded that all the tested OESS are safe and effective for the treatment of diarrhea in calves with moderate degrees of dehydration and metabolic acidosis, which indicates that they have proper compositions for this purpose.

Em um ensaio clínico controlado e aleatório, foram comparados os efeitos de cinco soluções eletrolíticas orais (SEOs) sobre os equilíbrios hídrico, eletrolítico e ácido-base de bezerros neonatos diarreicos. Diarreia osmótica e desidratação foram induzidas com sacarose no leite, espironolactona e hidroclorotiazida, por 48h, em 30 bezerros Holandeses com 10 dias de idade, 43,5 ± 3,8kg de peso, e alimentados com leite natural. Eles foram distribuídos em cinco grupos de tratamento (n=6) de acordo com a SEO administrada (comercial: SEO A, B, C, D; e não comercial: SEO UEL). No dia do tratamento, os bezerros receberam 6L de SEO em duas doses além da ingestão de leite. Amostras de sangue venoso foram coletadas em -48h (início da indução), - 24h, Oh (início do dia de tratamento), 8h, 16h, 24h, 48h e 72h. PPT, glicose, lactatos Le D, pH, pCO2, HCO3, BE, Na, K, CI, SID3, SIG, AG, Atot e variação percentual no volume plasmático (%VP) foram mensurados ou calculados, e analisados por meio de ANOVA de duas vias de medidas repetidas. Todos os bezerros desenvolveram diarreia osmótica, desidratação leve a moderada, hiponatremia, hipercloremia relativa e acidose metabólica moderada a grave. As SEOs testadas foram bem aceitas pelos bezerros e eficazes para a reversão da desidratação, dos desequilíbrios eletrolíticos e da acidose metabólica. A SEO D não corrigiu completamente a hiponatremia, e a SEO B causou hiperglicemia transitória. Conclui-se que todas as SEOs são eficazes para o tratamento da diarreia em bezerros com graus moderados de desidratação e de acidose metabólica, o que indica que possuem composições adequadas para esse fim.

Gingivitis in calves: longitudinal hematological and metabolic profiles- and salivary buffering capacity in animals treated with virginiamycin / Gengivites em bezerros: perfis longitudinais hematológicos, metabólicos e capacidade tamponante salivar em animais tratados com virginiamicina

Gingivitis is an infectious inflammatory process that generates local and systemic conditions, compromising the masticatory capacity of animals. Virginiamycin controls and prevents gingivitis and necrotizing gingivitis in cattle. However, the interaction and effect with different sera and salivary elements remain unknown. The present 6-month longitudinal study evaluated the hematological, metabolic, and salivary buffering capacity profiles of calves with gingivitis treated with virginiamycin. Ten calves were divided into two groups: control and virginiamycin (n = 5 each). Calves in the virginiamycin group had a lower occurrence of gingivitis (P < 0.01, Student's t-test). The animals that developed gingivitis in both experimental groups had higher salivary levels of alkaline phosphatase (P = 0.01915) and lower serum levels of albumin (P = 0.0028). Additionally, animals receiving virginiamycin had higher serum levels of magnesium (P = 0.008), albumin (P = 0.0008), urea (P = 0.008), alkaline phosphatase (P = 0.008), total proteins (P = 0.008), and plasma protein (P = 0.018). Salivary buffering capacity was negatively correlated with salivary variables such as calcium, magnesium, albumin, total protein, and aspartate aminotransferase and serum variables such as albumin and aspartate aminotransferase. Results of the present study suggested that the occurrence of periodontopathies in episodes is reflected in the local and systemic alterations in animals. In this context, clinical periodontal monitoring also showed the benefits of virginiamycin supplementation on gingival conditions and systemic health markers, in addition to controlling the two precursor forms of periodontitis.

Gengivites são processos infecto-inflamatórios que geram quadros locais e sistêmicos, com comprometimento da capacidade mastigatória dos animais. A virginiamicina controla e previne a gengivite e a gengivite necrosante em bovinos; no entanto, a interação e efeito com diferentes elementos séricos e salivares permanecem desconhecidos. O presente estudo teve como objetivo avaliar, em um estudo longitudinal com duração de seis meses, os perfis hematológicos, metabólicos e de capacidade tamponante salivar de bezerros com gengivite e tratados com virginiamicina. Foram utilizados 10 bezerros divididos em dois grupos: grupo controle (n = 5) e grupo virginiamicina (n = 5). Os bezerros do grupo virginiamicina apresentaram menor ocorrência de gengivite (P < 0,01, teste T - Student). Os animais que desenvolveram gengivite, de ambos os grupos experimentais, apresentaram níveis salivares mais elevados de fosfatase alcalina (P = 0,01915) e níveis séricos menores de albumina (P = 0,0028). Observou-se também que os animais que receberam virginiamicina apresentaram níveis séricos mais elevados de magnésio (P = 0,008), albumina (P = 0,0008), ureia (P = 0,008), fosfatase alcalina (P = 0,008), proteínas totais (P = 0,008) e proteína plasmática (P = 0,018). As análises de capacidade tamponante salivar foram correlacionadas negativamente às variáveis salivares como cálcio, magnésio, albumina, proteína total e aspartato aminotransferase e às variáveis séricas como a albumina e aspartato aminotransferase. Os resultados do presente estudo sugerem que a ocorrência em episódios das periodontopatias refletem-se em alterações locais e sistêmicas nos animais. Neste contexto, o monitoramento clínico periodontal também evidenciou os benefícios do emprego de suplementação pela virginiamicina sobre as condições gengivais e marcadores sistêmicos de saúde, além do controle das duas formas precursoras de periodontites.

Genetic diversity of Anaplasma marginale in calves under natural transmission conditions in the Northeast region of Pará / Diversidade genética de Anaplasma marginale em bezerros sob condições de transmissão natural na região Nordeste do Pará

The objective of the present study was to detect the genetic diversity of Anaplasma marginale strains in naturally infected calves from a rural property located in the northeastern region of the state of Pará, Eastern Amazon, which has a history of mortality due to anaplasmosis. Fourteen calves positive for A. marginale were selected using a semi-nested polymerase chain reaction for the target msp1α gene, with asymptomatic (n=3) and symptomatic (n=11) infections. After sequencing the samples, two genotypes were verified in the E and C regions and the structures in tandem repeats were determined. Nine different strains were found: eight related to the E genotype (α-ß-ß-Γ = one animal, asymptomatic; 16-F-17-F-F = two animals, symptomatic; α-ß-F-F-F-F = one animal, asymptomatic; 31-62-62-61 = one animal, symptomatic; τ-10-3 = three animals, two symptomatic and one asymptomatic; α-ß-ß-ß = one animal, symptomatic; τ-22 -13-18 = two animals, both symptomatic; ß-ß-ß-BRA1-31 = two animals, both symptomatic), and one related to genotype C (23-24-25-31-27-27 = one animal, asymptomatic). Genotype E was predominant in 92.86% of the samples (13/14), followed by genotype C (7.14%). This study made it possible to detect the genetic diversity of A. marginale in calves from the selected dairy farm, in addition to identifying the BRA1 sequence in the animals of the present study, which was recently diagnosed in Minas Gerais, demonstrating the dispersion of A. marginale strains in herds from different Brazilian states. Genetic diversity of A. marginale was observed in both symptomatic and asymptomatic calves. There were no significant differences when clinical signs were compared to the genotype verified in the infected animals. The prevalence of pathogenicity was not observed.

O objetivo do presente trabalho foi detectar a diversidade genética de cepas de Anaplasma marginale em bezerros naturalmente infectados oriundos de uma propriedade rural localizada na região nordeste do estado do Pará, Amazônia Oriental, a qual apresentava histórico de mortalidade devido à anaplasmose. Foram selecionados 14 bezerros positivos para A. marginale pela técnica de semi-nested PCR (nPCR) para o alvo no gene msp1α, com infecção assintomática (n=3) e sintomáticos (n=11). Após o sequenciamento das amostras foram verificados dois genótipos nas regiões E e C, e determinadas as estruturas em tandem repeats. Nove diferentes estirpes foram encontradas, sendo oito relacionadas ao genótipo E (α-ß-ß-Γ = um animal, assintomático; 16-F-17-F-F = dois animais, sintomáticos; α-ß-F-F-F-F = um animal, assintomático; 31-62-62-61 = um animal, sintomático; τ-10-3 = três animais, dois sintomáticos e um assintomático; α-ß-ß-ß = um animal, sintomático; τ-22-13-18 = dois animais, sintomáticos; ß-ß-ß-BRA1-31 = dois animais, sintomáticos) e uma relacionada ao genótipo C (23-24-25-31-27-27 = um animal, assintomático). O genótipo E foi predominante em 92,86% das amostras (13/14), seguido pelo genótipo C (7,14%). O estudo possibilitou a detecção da diversidade genética de A. marginale em bezerros dessa propriedade leiteira, além de identificar a sequência BRA1 nos animais do presente estudo, a qual foi diagnosticada recentemente em Minas Gerais, o que demonstra a dispersão das estirpes de A. marginale nos rebanhos de diferentes estados brasileiros. A diversidade genética de A. marginale foi observada tanto em bezerros sintomáticos quanto em assintomáticos e não houve diferença significativa quando se comparou os sinais clínicos ao genótipo verificado no animal infectado, não observando a prevalência de patogenicidade de estirpes.

Vitamin A deficiency as a cause of blindness in feedlot calves / Deficiência de vitamina A como causa de cegueira em bezerros confinados

Vitamin A is an essential micronutrient to reproduction, development, normal growth, and function of the nervous system and vision, especially in growing animals. Hypovitaminosis A can affect any of these functions. The aim of this study was to describe the epidemiology, clinical signs, pathological aspects, and diagnostic approach in an outbreak of blindness in feedlot calves fed only grain. Five of 57 ten-month-old calves became blind after eight months at the feedlot. Clinical signs were mydriasis, absent pupillary and menace reflexes, bilaterally. Hypovitaminosis A was suspected and subsequently confirmed by low serum levels of vitamin A. One calf was euthanized and necropsied, and no gross findings were present. Histopathological lesions were restricted to the retina and characterized by degeneration and atrophy of the photoreceptor layer and some retinal scars. The calves were treated with intramuscular vitamin A injection at a dose of 5,000 international units (IU) per kilogram of body weight (kg BW) every 60 days until slaughter. Affected calves did not recover visual capacity, but no other cases occurred.

Vitamina A é um micronutriente essencial para reprodução, desenvolvimento, crescimento normal, além de participar do funcionamento do sistema nervoso central e visão, especialmente em animais em crescimento. Hipovitaminose A pode afetar qualquer uma dessas funções. O objetivo desse artigo é descrever a epidemiologia, sinais clínicos, aspectos patológicos e abordagem diagnóstica em um surto de cegueira em bezerros confinados alimentados apenas com grãos. De 57 bezerros de dez meses de idade, cinco ficaram cegos após oito meses no confinamento. Os sinais clínicos eram midríase, ausência de reflexo pupilar a luz e de ameaça, bilateralmente. Suspeitou-se de hipovitaminose A, que foi subsequentemente confirmada pelos baixos níveis séricos de vitamina A. Um bezerro foi eutanasiado e necropsiado, e alterações macroscópicas não foram encontradas. Lesões histopatológicas estavam restritas a retina e caracterizavam-se por degeneração e atrofia da camada de fotorreceptores, além de cicatrizes na retina. Os bezerros foram tratados com injeção intramuscular de vitamina A, na dose de 5.000 unidades internacionais (UI) por quilograma de peso vivo (Kg PV) a cada 60 dias, até o dia do abate. Os bezerros afetados não recuperaram a capacidade visual, mas novos casos não ocorreram.

Spontaneous fractures and hypocuprosis in pen-backgrounded Holstein calves

Bone fractures are a frequent cause of limp in cattle, being pre-existing bone lesions among the predisposing factors. However, there is scant information about the natural occurrence of bone disease. This report aimed to describe an outbreak of spontaneous fractures associated with hypocuprosis in pen-backgrounded calves. Hind limp and irreversible recumbency were noticed in 9-month-old calves of a dairy farm from Córdoba province (Argentina). The issue was only evident in males fed a diet composed (DM) of 57% wet corn, 24% dry corn distiller grains, and 19% corn silage. No mineral mix was supplied. Accumulated morbidity and fatality rates were 5.8 and 100%, respectively. Two autopsies were performed, observing multiple femoral and rib fractures. Severe hypocupremia, very low copper levels in the liver and plasma, deficient dietary copper levels, normocalcemia, marginal hypophosphatemia, and high sulfate concentrations in the water supply were determined. Except for the decreased bone quantity and the multiple fractures, no bone lesion was observed, confirming osteoporosis as the pathological diagnosis, and hypocuprosis as the etiology.(AU)

Behavioral changes in dairy calves raised in outdoor holding pens with alternative roofing / Alterações comportamentais de bezerras criadas em bezerreiros tropicais com cobertura alternativa

This study assessed the behavior of dairy calves raised in outdoor holding pens covered with different geosynthetics. Twenty crossbred (Girolando, Jersey and Holstein) dairy calves undergoing weaning were used, with an average initial live weight of 40.6 Kg. A completely randomized block design was used, with a 4 x 3 factorial scheme and 5 repetitions. The roofing materials were polyethylene mesh, drainage geocomposite, nonwoven geotextile and woven geotextile, representing the first factor, and assessment times (8 to 11 a.m., 11:15 a.m. to 2 p.m. and 2:15 to 6 p.m.) the second factor. Environmental variables were analyzed, and the following heat stress indices calculated: black globe-humidity index (BGHI) and equivalent temperature. The average BGHI and equivalent temperature were 79 and 26, respectively. Walking behavior differed between treatments (P<0.05) and was more frequent in the woven geotextile treatment. The most frequent behavior observed throughout the day was lying in the shade (53%), demonstrating the importance of providing artificial shading during this stage of life. When compared to polyethylene mesh, the drainage geocomposite and nonwoven geotextile were better suited to providing shade for dairy calves undergoing weaning in tropical regions.

O trabalho avaliou o comportamento de bezerras leiteiras, criadas em bezerreiros de modelo tropical, contendo diferentes geossintéticos como material de cobertura. Foram avaliadas 20 fêmeas Girolando, Jersey e Holandesa com peso inicial médio de 40,6 Kg durante a fase de aleitamento. O delineamento experimental foi de blocos casualizados completos, em arranjo fatorial 4 x 3 com 5 repetições. Os materiais de cobertura foram: malha de polietileno, geocomposto drenante, geotêxtil não-tecido e geotêxtil tecido foram o primeiro fator e os períodos do dia (08 às 11, 11:15 às 14 e 14:15 às 18 horas) foram o segundo fator. Foram avaliadas as variáveis ambientais e calculados os índices de conforto térmico: índice de temperatura do globo negro e umidade e índice de temperatura equivalente. As médias do índice de temperatura do globo negro e índice de temperatura equivalente foram 79 e 26, respectivamente. O comportamento andando diferiu entre tratamentos (P<0,05), sendo mais frequente no tratamento geotêxtil tecido. A frequência comportamental mais observada ao longo do dia foi deitada à sombra (53%) deixando evidente a importância da disponibilização de sombreamento artificial para essa fase de vida. Os materiais de cobertura geossintéticos Geodrenante e Geotêxtil não-tecido, comparados à malha de polietileno, foram os mais apropriados para a utilização como sombreamento em regiões de clima tropical para bezerras em fase de aleitamento.

Cryptosporidium infection in diarrheal bovine dairy calves: occurrence and risk factors in Santa Catarina, Brazil / Infecção por Cryptosporidium em bezerros com diarreia: ocorrência e fatores de risco em Santa Catarina, Brasil

Cryptosporidium protozoa genus are parasites that cause acute enteric disease in young and immunocompromised animals, resulting in anorexia, loss and decrease in weight gain, and, in severe cases, death. Therefore, this study aimed: i) to determine the occurrence of Cryptosporidium spp. in calves with clinical diarrhea in different regions of Santa Catarina, Brazil; ii) to evaluate the risk factors involved with the frequency of infection. iii) to determine the species most involved with the disease in the region. For this, 425 samples were collected in 141 dairy farms, from animals with ages ranging from 0 to 150 days. For this purpose, the samples were submitted to the modified Ziehl-Neelsen technique, with molecular analysis of the positive samples being performed. It was observed 62.1% occurrence of Cryptosporidium spp. in this sampling, especially between 8 to 15 days. Regarding the risk factors evaluated, such as age, management, facilities, water source and Koppen climate (CFA and CFB), none showed statistical significance. Samples positive by the Ziehl-Neelsen technique (32 samples) were randomly selected for molecular diagnosis. Of these, 10 were sequenced, allowing the identification of Crypstosporidium parvum in 6 samples. However, this study proves the existence and high occurrence of the protozoan in different regions of the state of Santa Catarina, Brazil.

Os protozoários do gênero Cryptosporidium são parasitas que causam doença entérica aguda em animais jovens e imunocomprometidos, resultando em anorexia, perda e diminuição do ganho de peso e, em casos graves, morte. Portanto, este estudo teve como objetivo determinar a ocorrência de Cryptosporidium spp. em bezerros com diarreia clínica em diferentes regiões de Santa Catarina, Brasil; bem como avaliar os fatores de risco envolvidos com a frequência de infecção. Além disso, com um número seleto de amostras, buscou-se determinar as espécies mais envolvidas com a doença na região por meio de técnicas moleculares. Para isso, foram coletadas 425 amostras em 141 fazendas leiteiras, de animais com idade variando de 0 a 150 dias. Observou-se 62,1% de ocorrência de Cryptosporidium spp. nesta amostragem, principalmente entre 8 a 15 dias. Em relação aos fatores de risco avaliados, como idade, manejo, instalações, fonte hídrica e clima de Koppen (CFA e CFB), nenhum apresentou significância estatística. No entanto, este estudo comprova a existência e alta ocorrência do protozoário em diferentes regiões do estado de Santa Catarina, Brasil.