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Bovine mastitis is an important and costly disease to dairy cattle. Diagnostic methods usually performed in Brazil are somatic cell counts (SCC) and milk microbiology. Low bacteria shedding in milk implies no colony growth in microbiological tests and false negative results. Streptococcus agalactiae and Staphylococcus aureus are principal pathogens of mixed mastitis. However, S. agalactiae has a higher bacterial release from the mammary gland than S. aureus, affecting microbiological sensitivity to diagnose S. aureus. This study aimed to estimate the SCC and total bacterial count (TBC) from cows according to pathogen isolated in milk and to evaluate variation in S. aureus diagnosis by a microbiological test during S. agalactiae treatment, which is called blitz therapy. Both S. agalactiae and S. aureus presented high SCC means, although S. agalactiae showed shedding of bacteria 2.3 times greater than S. aureus. Microbiological sensitivity to S. aureus increased for 5 months during S. agalactiae treatment. The prevalence of S. agalactiae fell after 5 months of therapeutic procedures. The prevalence of S. aureus increased to 39.0. The results showed that due to high sensitivity, the polymerase chain reaction (PCR) could be used at the beginning of blitz therapy with the goal of S. agalactiae eradication from the dairy herd.

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This study evaluated the economic impacts caused by mastitis in a small dairy farm with similar characteristics and production to most dairy farms in southern Brazil and investigated if climatic variations influenced mastitis occurrence in the region. A farm with, on average, 45 lactating Holstein cattle was monitored from November 2021 to October 2022, and data on mastitis cases, bulk tank milk somatic cell count, animal treatment costs, milk production, animal disposal costs, and production losses were collected. Monthly averages of temperature, relative humidity (RH), and rainfall in the region were obtained. The greatest loss was related to the drop in milk production, resulting in 63.8% of total losses, followed by animal disposal (29.5%), milk disposal (4.6%), and treating animals with mastitis (2.0%), totaling a 10.6% reduction in the annual gross income. There were negative correlations between the clinical mastitis rate and monthly RH and between subclinical mastitis and temperature; the occurrence of subclinical mastitis and average RH were positively correlated. Our findings showed that mastitis negatively impacted the economy and that climate influenced mastitis occurrence.

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This study addresses the hypothesis that different acute stressors can cumulatively decrease milk yield. In fact, in a time of global warming, the impact of environmental stress and farm management practices on milk production remains unclear. In this context, our objective was to investigate the effect of acute and cumulative stress on gene expression in mammary tissue and their interactions with physiological responses and milk yield in Saanen goats. Thirty lactating goats were subjected to two treatments: (1) control (CT), in which goats were maintained following a habitual routine under comfort conditions; (2) stress (ST), in which the goats were subjected to different types of environmental stress: heat stress, adrenocorticotropic hormone administration, hoof care management, and exposure to rain. These stressors were performed sequentially, with one stress per day on four consecutive lactation days, to evaluate their effect on milk quality and milk yield. Our results showed that compared to CT goats, cumulative stress increased the gene expression of glucocorticoid receptor (GR), interferon-gamma (IFN-γ), superoxide dismutase (SOD), and catalase (CAT) in mammary tissue, which are indicators of cortisol action, inflammatory response, and antioxidant enzymes. Furthermore, the acute challenges imposed on ST goats changed their rectal temperature and respiratory frequency and increased cortisol, glucose, cholesterol, triglycerides, and high-density lipoprotein release in plasma when compared to CT goats. Although these physiological and metabolic responses restore homeostasis, ST goats showed lower milk yield and higher somatic cell count in milk than CT goats. In conclusion, the results confirmed our initial hypothesis that different acute stressors cumulatively decrease the milk yield in Saanen goats.

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Background and Aim: Bovine mastitis is one of the most costly and prevalent diseases in dairy herds, which can be prevented and controlled through proper milking practices, diagnosis, and elimination of chronic animals, among others. Contagious pathogens such as Staphylococcus aureus and environmental pathogens such as Escherichia coli and Klebsiella spp. can affect cows and milk for human consumption, generating a public health risk. This study aimed to estimate the prevalence of herds with somatic cell count (SCC) ≥200,000 cells/mL, S. aureus, E. coli, and Klebsiella spp., in bulk tank milk (BTM) and its associated risk factors in Colombian dairy cow herds. Materials and Methods: A cross-sectional probabilistic study was carried out in 150 dairy herds located in the north of the Antioquia province. A single visit per herd was conducted, during which three BTM samples were aseptically collected. General data and milking practices were collected through an epidemiological survey applied in each herd. Results: The prevalence of S. aureus, E. coli, and Klebsiella spp. were 14% (21/150), 2% (3/150), and 8% (12/150), respectively. Moreover, 95% of the herds presented an SCC of ≥200,000 cells/mL. Practices such as in-paddock milking, change of milker during the last month, use of disposable gloves, and hand disinfection were associated with increased prevalence of S. aureus, whereas proper dipping was a protective factor. Proper washing and disinfection of the milking machine, use of chlorinated disinfectants for hand hygiene, and use of disposable gloves decreased the prevalence of E. coli and Klebsiella spp. Bulk tank SCC increased in herds with 30-60 milking cows, herds with >60 milking cows, and herds with a change of milker during the last month. Hand disinfection and dipping decreased the SCC. Conclusion: Staphylococcus aureus, E. coli, and Klebsiella spp. were prevalent in BTM from dairy cow herds. The risk of S. aureus isolation was higher in herds with an in-paddock milking system. The risk of E. coli and Klebsiella spp. isolation were higher in herds with >60 milking cows, with a change of milker during the last month. Processes such as avoiding changing the milker and greater control in medium and large herds could improve the SCC in BTM.

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The present study explored the predictive values of milk leukocyte differentials (MLD) as a basis for improving the diagnosis of intramammary infections (IMIs) and subclinical mastitis. Quarter milk samples were collected for bacteriological analysis, quarter somatic cell count (qSCC), and MLD. The MLD were assessed using the cytospin technique, direct microscopic smears, and flow cytometry. The predictive values of each single leukocyte population and useful potential indices that could better reflect immune complexity were also calculated. Changes in the percentage of any leukocyte alone failed to substantially improve the predictive value of qSCC in diagnosing IMIs. Although certain parameters increased the area under the receiver operating characteristic curve (ROC curve) as a result of increased specificity values, a slight reduction in sensitivity was observed. The so-called CD8 complex was a unique parameter which improved both the sensitivity (78.79 %) and the specificity (80.77 %) in IMI diagnosis, resulting in the highest area under the ROC curve (0.87). To diagnose subclinical mastitis, the percentage of macrophages and the sum of the percentage PMNLs and T CD8+ cells divided by the percentage of macrophages showed the highest predictive values (sensitivity = 79.63, specificity = 73.68, and area under the ROC curve = 0.83) in the differentiation of the inflammatory condition status of cows. In conclusion, this study provides further insights into using T CD8+ lymphocytes in diagnosing bovine IMIs, combined with PMNLs and macrophages. The antidromic trend of macrophages vs. PMNLs and T CD8+ lymphocytes due to the increasing qSCCs was crucial to differentiating quarters under both inflammatory and non-inflammatory conditions.

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Poor udder health status can have a detrimental effect on milk yield and reproductive performance, leading to reductions in the dairy farm profit. The objective of this retrospective longitudinal study was to assess the associations of somatic cell count (SCC) with daily milk yield and reproductive performance. A database with 1,930,376 lactations from 867 Argentinean grazing dairy herds records collected for 14 years was used. The association of the evolution of SCC (healthy vs. new case vs. cured vs. chronic; with 150,000 SCC/mL as threshold) and of the severity of SCC [mild (150,000--400,000 SCC/mL) vs. moderate (400,000-1,000,000 SCC/mL) vs. severe (>1,000,000 SCC/mL)] with the odds for conception were estimated. Finally, the associations of the linear score of SCC (LS-SCC) with daily milk yield were estimated depending on parity and milk production quartile. The odds ratios (CI 95%) for conception at first service were 0.921 (0.902-0.941), 0.866 (0.848-0.884), and 0.842 (0.826-0.859) for the new case, cured, and chronic cows compared with healthy cows, respectively. Also, the odds ratios (CI 95%) for conception were 0.902 (0.881-0.925), 0.837 (0.808-0.866) and 0.709 (0.683-0.736) for mild, moderate and severe cases compared with healthy cows, respectively. An increase of one point of LS-SCC was associated with decreases of 0.349, 0.539, and 0.676 kg in daily milk yield for first-, second-, and third-lactation cows, respectively. In conclusion, SCC is negatively associated with the risk for conception and with daily milk yield in grazing dairy cows. This negative relationship with conception is higher when SCC increase occurs after the service date and it is influenced by severity of mastitis, and in the case of milk yield, the negative association is influenced by parity, milk production quartile, and severity of mastitis.

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As mycotoxins are consistent contaminants in the dairy cow diet, the use of adsorbents is recommended, although there are no ideal adsorbents. Although there are studies on this subject, few have focused on chronic natural intoxications. Here, we evaluated the effect of bentonite adsorbents associated with liver antioxidants on the health and milk production of dairy cows fed a diet containing naturally-produced fumonisin, zearalenone, and deoxynivalenol. Eighteen dairy cows (bodyweight 550 ±50 kg, 5 ± 2 years old, and 30 ± 1,25 kg/day milk production) in the middle of lactation were divided into groups: treatment (TG, n = 9, 22 g/day of supplement added to diet) and control (CG, n = 9, without supplement). A physical examination was performed, weekly over 56 days and blood was collected for liver and immune assessments. Milk was harvested to evaluate milk production and content (fat protein, somatic cell count, and lactose). The additive promoted beneficial effects on the liver from the 24th day due to a decrease in the enzymatic activities of gamma-glutamyltransferase and lactate dehydrogenase and increased serum protein and albumin levels. There were improvements in health, evidenced as fewer clinical manifestations of the disease, greater leukocyte oxidative metabolism capacity, and a lower neutrophil lymphocytes ratio. The treatment also promoted a 19% increase in milk volume. It was concluded that the additive promoted health benefits and milk production in dairy cows.(AU)

Como as micotoxinas são contaminantes constantes na dieta de vacas leiteiras, o uso de adsorventes é recomendado, embora não existam adsorventes ideiais. Ainda que existam estudos sobre o assunto, poucos são direcionados às intoxicações naturais crônicas. Nosso experimento avaliou o efeito do adsorvente bentonita associado a antioxidantes hepáticos sobre a saúde e produção de leite de vacas leiteiras alimentadas com dieta contendo fumonisina, zearalenona e desoxinivalenol produzidos naturalmente. Dezoito vacas lei-teiras (peso corporal 550 ±50 kg, 5±2 anos de idade, e 30 ± 1,25 kg/dia de produção de leite) no meio da lactação, foram divididas em grupos: Tratamento (GT, n=9, 22g/dia do suplemento adicionado à dieta) e controle (GC, n =9, sem suplemento). Em intervalos semanais, durante 56 dias, foi realizado exame físico, coleta de sangue para avaliação hepática e imunológica. O leite foi colhido para avaliar a produção e análises de leite para (proteína, gordura, contagem de células somáticas e lactose). O aditivo promoveu efeitos bené-ficos no fígado à partir do 24º dia devido à diminuição das atividades enzimáticas da gama-glutamiltransferase e lactato desidrogenase e aumento dos níveis séricos de proteína e albumina. Houve melhora na saúde, evidenciada por menor número de manifestações clínicas de doença, maior capacidade de metabolismo oxidativo dos leucócitos e menor razão neutrófilos/linfócitos. O tratamento também promo-veu aumento de 19% no volume de leite. Concluiu-se que o aditivo promoveu benefícios à saúde e à produção de leite em vacas leiteiras.(AU)

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Subclinical mastitis is a very important disease for dairy cattle farms. As a result of the deterioration of milk quality, it causes economic losses in enterprises. Milk samples of 180 cows were divided into five groups according to the somatic cell count. Some chemical properties and composition were measured in milk samples. The ratio of solid-non-fat, mineral matter, lactose, and protein decreased as the somatic cell count of the milk increased (P<0.05). No statistical difference was observed between the fat content of milk and the level of somatic cell count (P>0.05). Although specific gravity decreases (P<0.05), the electrical conductivity increases (P<0.001) in milk with high levels of somatic cell count. The milk quality of dairy cattle deteriorates due to the high somatic cell count. Therefore, regular monitoring of somatic cell count is recommended in dairy farms to monitor changes in fat, protein, solid-non-fat, lactose, and mineral matter ratios as well as some chemical properties that make up the milk composition.

A mastite subclínica é uma doença muito importante para as fazendas de gado leiteiro. Como resultado da deterioração da qualidade do leite, ela causa perdas econômicas nas empresas. Amostras de leite de 180 vacas foram divididas em cinco grupos de acordo com o nível de contagem de células somáticas (SCC). Algumas propriedades químicas e composição foram medidas em amostras de leite. A proporção de sólido sem gordura, matéria mineral, lactose e proteína diminuiu à medida que a SCC do leite aumentava (P<0,05). Nenhuma diferença estatística foi observada entre o conteúdo de gordura do leite e o nível de contagem de células somáticas (P>0,05). Embora a gravidade específica diminua (P<0,05), a condutividade elétrica aumenta (P<0,001) no leite com altos níveis de contagem de células somáticas. A qualidade do leite do gado leiteiro se deteriora devido à alta contagem de células somáticas. Portanto, o monitoramento regular da SCC é recomendado nas fazendas de leite para monitorar mudanças nas proporções de gordura, proteína, sólidos não gordurosos, lactose e matéria mineral, bem como algumas propriedades químicas que compõem a composição do leite.

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Consumers demand for food safety affects dairy industry, restraining the sector to adapt to milk quality parameters established by legislation, such as somatic cell count (SCC) and standard plate count (SPC). Good agricultural practices have positive impact over these parameters, especially Forestripping Milk (FSM), which consists of observing the first milk streams collected in a dark-bottomed mug for identification of clinical mastitis. These first milk streams have high somatic cells count and bacteria. Therefore, the aim of this study was to evaluate the characteristics of milk from FSM, such as SCC and SPC values, and its impacts on milk quality of the cooling tank through simulating contamination. Fourteen dairy farms and one experimental farm were evaluated for SCC and SPC parameters of FSM. It was observed that there was no statistically significant difference for SCC and SPC between milk samples from the cooling tank and cooling tank simulating the inclusion of milk from FSM. Statistically significant difference for somatic cell score (SCS) and SPC was observed when tanks were classified by SCC. In addition, difference in SCS was observed between morning and afternoon milking. The collection of first milk streams can contribute to decrease in SCC and SPC of milk in the cooling tank. FSM must be practiced by all dairy farmers as milking management, to assist in clinical mastitis diagnosis and improve milk quality.(AU)

A exigência dos consumidores por alimentos seguros pressiona a indústria leiteira a se adequar aos parâmetros esta-belecidos pela legislação, como a contagem de células somáticas (CCS) e a contagem padrão em placas (CPP). As boas práticas agropecuárias impactam positivamente sobre esses parâmetros, destacando-se o teste de Tamis ou Forestripping Milk (FSM), que consiste na observação dos primeiros jatos de leite retirados em uma caneca de fundo escuro para a identificação da mastite clínica. Esses primeiros jatos possuem elevada quantidade de células somáticas e bactérias. O objetivo deste estudo foi avaliar as características do leite do FSM quanto aos valores de CCS e CPP, e seus impactos na qualidade do leite do tanque de res-friamento por meio de simulação de contaminação. Foram avaliadas 14 propriedades leiteiras comerciais e uma experimental quanto aos parâmetros de CCS e CPP oriundos do FSM. Observou-se que não houve diferença significante para CCS e CPP entre as amostras de leite do tanque e do tanque simulando a inclusão de leite do FSM. Diferenças estatisticamente significa-tivas para escore de CCS e CPP foram observadas quando os tanques foram classificados por CCS. Além disso, foi observada diferença nas CCS entre as ordenha da manhã e da tarde. A coleta dos primeiros fluxos de leite pode contribuir na redução da CCS e da CPP do leite do tanque de resfriamento. O FSM deve ser praticado por todos os produtores de leite no manejo da ordenha para auxiliar no diagnóstico clínico da mastite e melhorar a qualidade do leite.(AU)

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Abstract Mastitis is the most common disease in dairy herds and the main cause of economic losses in milk production worldwide. This inflammatory reaction of the mammary gland affects the quantity, composition and quality of milk produced and its suitability for the dairy industry. Despite of its importance, Colombia has no regulations on somatic cell count (SCC); that is, no official upper limits have been established for the dairy industry. The current quality-based payment system for raw milk does not encourage local producers to reduce the level of somatic cells. Consequently, Colombia is at a disadvantage compared to countries that include this parameter in their payment schemes and subscribe to international free trade agreements, affecting the competitiveness of the Colombian dairy sector. This article reviews the types of somatic cells, the microbiology of mastitis, its etiology and diagnosis, the changes that generate the composition of milk, and the impact of high SCCs on the quality of dairy products, such as yogurt, cheese, and milk powder. The final section offers a reflection on the problem of high SCCs in Colombia and the lack of regulations in this regard.

Resumen La mastitis es la enfermedad más frecuente en los hatos lecheros y es la principal causa de pérdidas económicas en la producción de leche alrededor del mundo. Esta reacción inflamatoria de la glándula mamaria afecta la cantidad, composición, calidad y aptitud de la leche para procesamiento por la industria. Sin embargo, en Colombia no existe normatividad sobre el recuento de células somáticas, principal indicador de mastitis; es decir, no existen límites oficiales que sirvan de referencia para la industria lechera. El sistema de pago basado en calidad no incentiva al productor a disminuir el nivel de células somáticas. Esto coloca al país en desventaja frente a otros países que exigen este parámetro en su esquema de pago y con los cuales Colombia tiene tratados de libre comercio, afectando negativamente la competitividad del sector lechero colombiano. En este artículo se hace una revisión sobre los tipos de células somáticas, la microbiología de la mastitis, su etiología, el diagnóstico, los cambios que generan la composición de la leche y el impacto que tienen los altos recuentos de células somáticas sobre la calidad de algunos derivados lácteos como yogures, quesos y leche en polvo. En la parte final se presenta una reflexión sobre la problemática de los altos recuentos de células somáticas en Colombia y la falta de normatividad al respecto.

Resumo A mastite é a doença mais frequente nos rebanhos leiteiros e é a principal causa de perdas econômicas na produção de leite em todo o mundo. Essa reação inflamatória da glândula mamária causa efeitos na quantidade, composição, qualidade e aptidão de leite processado pela indústria. No entanto, na Colômbia, não há regulamentação sobre a contagem de células somáticas até o momento, o principal indicador de mastite, ou seja, não há limites oficiais que sejam referência para a indústria leiteira. O sistema de pagamento baseado na qualidade não incentiva o produtor a diminuir o nível de células somáticas. Isso coloca o país em desvantagem em comparação com outros países que exigem esse parâmetro em seu esquema de pagamento e com quem a Colômbia possui acordos de livre comércio, afetando negativamente a competitividade do setor. Este documento analisa os tipos de células somáticas, a microbiologia da mastite, sua etiologia, diagnóstico, alterações na composição do leite e o impacto da alta contagem de células somáticas na qualidade do leite. Alguns derivados de leite, como iogurtes, queijos e leite em pó. Na parte final, é feita uma reflexão sobre o problema da alta contagem de células somáticas na Colômbia e a falta de regulamentação nesse sentido.

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ABSTRACT Mastitis is one of the most important illnesses in specialized dairy herds worldwide due to the effects on production and animal health. The types caused by CNS has a special importance in a production where the main pathogens are controlled. The objective of the present work is to determine the prevalence of CNS in a dairy herd in Boyaca and also quantify the effects of every species of CNS in SCC. 40 cows were selected and sampled during 6 months, CMT was performed, and results from 1 to trace were sampled. The routine bacteriological test was also performed for CNS identification, and the isolating of CNS was performed through rpoB gene identification and through the type of strain using the pulse gel electrophoresis procedure. Out of 960 samples, 619 were positive for CNS growth. The most prevalent species were Staphylococcus epidermidis, S. chromogenes, S. sciuri, S. simulaans, S. haemolyticus and S. capitis. The results that were found here are similar to the results observed in different parts of the world, which confirms that they are pathogens that must be constantly evaluated because they can go unnoticed in routine controls, especially in those farms where major pathogens are not a serious problem. The results determined in this study demonstrate that CNS generates a slight increase in somatic cells.

RESUMEN La mastitis es una de las enfermedades más importantes en los rebaños lecheros especializados alrededor de todo el mundo debido a los efectos sobre la producción y la salud animal. Los tipos ocasionados por estafilococos coagualasa negativo (ECN) tienen una importancia especial en una producción en la que los principales patógenos están controlados. El objetivo del presente trabajo es determinar la prevalência del ECN en un hato lechero en Boyacá y cuantificar los efectos de cada especie de ECN en el conteo de células somáticas (CCS). Se seleccionaron 40 vacas y se tomaron muestras durante 6 meses, se realizó california mastitis test (CMT) y se tomaron muestras de los resultados desde 1 hasta donde hubo trazas. También se realizó la prueba bacteriológica de rutina para la identificación del ECN y el aislamiento del ECN se realizó mediante la identificación del gen rpoB y del tipo de cepa, usando el procedimiento de electroforesis en gel de pulso. De 960 muestras, 619 fueron positivas para el crecimiento del ECN. Las especies más prevalentes fueron Staphylococcus epidermidis, S. chromogenes, S. sciuri, S. simulans, S. haemolyticus y S. capitis. Los resultados encontrados aquí son similares a resultados en diferentes partes del mundo, lo que confirma que son patógenos que deben ser evaluados constantemente porque pueden pasar desapercibidos en los controles de rutina, especialmente en aquellas fincas donde los patógenos mayores no son un problema grave. Los resultados determinados en este estudio demuestran que el SNC genera un ligero aumento de células somáticas.

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Systemic parameters and its relationship with Somatic Cell Count (SCC) in dairy cows were evaluated. Cows that presented subclinical mastitis (SMC; n = 16) and healthy cows (HC; n = 6) were selected and identified by the California Mastitis Test and SCC in milk. SCC results were logarithmically transformed into somatic cell score (SCS). HC presented SCS 〈 4.32 while SMC presented SCS 〉 4.32. Milk and blood samples were collected in three days: D1 (first day of sampling), D2 (48 h after D1) and D3 (7 days after D1), to determine White Blood Cells (WBC), albumin, total protein, total bilirubin and malondialdehyde (MDA). Results were expressed as mean ± standard deviation. It was considered significant at P < 0.05. The data of SCS on D1, D2 and D3 in SMC were: 6.8 ± 1.7, 6.4 ± 1.8, and 6.3 ± 2.0, respectively. In SMC the MDA (nmolL-1) were: D1 - 9.3 ± 2.6, D2 - 8.6 ± 2.4, and D3 - 11.5 ± 3.5. The MDA on D3 in SMC (11.5 ± 3.5) were increase when compared to HC (6.0 ± 1.3) (P < 0.001). No significant difference was found in WBC, TP, ALB, and TB between groups. It was observed a positive correlation between MDA-SCS (ρ = 0.4) and between WBC-SCS (ρ = 0.3) in the SMC group. It was concluded that the systemic repercussion damage in the mammary gland promoted by subclinical mastitis in dairy cows can be assessed using the MDA and WBC biomarkers.

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Somatic cell count (SCC) can be used as a proxy for the prevalence of mastitis in a herd, reflecting the hygiene conditions and management practices on dairy farms, and thus an indicator of milk quality. In this study, we investigated how the adoption of management practices in milking systems can contribute to the reduction of SCC levels and improve milk quality. We collected data regarding management practices from 91 dairy farms in three municipalities of southeastern Pará: Parauapebas, Curionópolis, and Eldorado dos Carajás. Fifty milliliters of milk from each farm were collected in bottles containing bronopol, to preserve SCC. An exploratory factorial analysis (EFA) was performed to reduce the number of variables (management techniques) on dairy farms to some latent factors. We then used the selected factors to estimate the bovine mastitis management index to classify farms according to their use of technology and management techniques. Our results showed that most of the farmers (65.9%) used management techniques inefficiently in their systems, resulting in a significant loss of product quality, while only 3.3% had adopted the full set of techniques. The EFA results demonstrated that simple management practices including regular cleaning of the milking lines, a strip cup test, the California mastitis test, and washing teats with water before milking could be adopted to improve milk quality. However, in scenarios where the regulations become more rigorous, most farmers are unable to meet the maximum allowable SCC requirements, necessitating management innovations to reduce SCC. Therefore, the dissemination of knowledge, technical assistance, and access to new technologies is essential for improving management practices, and thus milk quality.

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OBJECTIVE: The objective of this study was to evaluate the genetic behavior of a population of Holstein cattle in response to the variation of environmental temperature by analyzing the effects of genotype by environment interaction (GEI) through reaction norms for the somatic cell score (SCS). METHODS: Data was collected for 67,206 primiparous cows from the database of the Paraná Holstein Breeders Association in Brazil, with the aim of evaluating the temperature effect, considered as an environmental variable, distinguished under six gradients, with the variation range found being 17°C to 19.5°C, over the region. A reaction norm model was adopted utilizing the fourth order under the Legendre polynomials, using the mixed models of analysis by the restricted maximum likelihood method by the WOMBAT software. Additionally, the genetic behavior of the 15 most representative bulls was assessed, in response to the changes in the temperature gradient. RESULTS: A mean score of 2.66 and a heritability variation from 0.17 to 0.23 was found in the regional temperature increase. The correlation between the environmental gradients proved to be higher than 0.80. Distinctive genetic behaviors were observed according to the increase in regional temperature, with an observed increase of up to 0.258 in the breeding values of some animals, as well as a reduction in the breeding of up to 0.793, with occasional reclassifications being observed as the temperature increased. CONCLUSION: Non-relevant GEI for SCS were observed in Holstein cattle herds of southern Brazil. Thus, the inclusion of the temperature effect in the model of genetic evaluation of SCS for the southern Brazilian Holstein breed is not required.

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The aim of the present study was to monitor cow milk quality and composition in two farms in the Noroeste Rio-grandense mesoregion, located in the municipalities of Palmeira das Missões and Pinhal - RS. Both herds were mixed, with animals of the Holstein (70%) and Jersey (30%) breeds. The following overall parameters were evaluated: body condition score (BCS), udder dirtiness, and calving order, and the following milk composition factors were measured: total dry extract (TDE), defatted dry extract (DDE), milk lactose, fat, and protein contents, casein, milk urea nitrogen (MUN), and somatic cell count (SCC). Multivariate statistical analysis was performed, and four factors were identified representing combinations of the measured variables. The first factor comprised negative relationships between milk production and cow breed, milk fat content, and milk protein content. The second factor comprised the positive relationships between lactation days and body condition score and milk protein content. The third factor represented the negative relationships between milk lactose content and SCC score, calving order, and BCS. The fourth factor was composed of the positive relationship between delivery order and udder dirtiness. Cluster analysis revealed that individual cows could be categorized into three groups. Monitoring the breed, calving order, body condition score, lactation days, milk production, fat, protein, and lactose contents, somatic cell counts, and udder dirtiness in cows allows greater control of the herd, allowing potential shortcomings to be rectified quickly and economic losses to production to be minimized.(AU)

Objetivou-se realizar o monitoramento por vaca em lactação referente a qualidade e composição do leite de duas propriedades rurais na mesorregião Noroeste Rio-grandense, localizadas nos municípios de Palmeira das Missões e Pinhal - RS. Ambos os rebanhos eram mistos, com animais da raça Holandês (70%) e Jersey (30%). Foram avaliados os parâmetros: escore de condição corporal (ECC), sujidade de úbere, ordem de parto e composição do leite: teores de extrato seco total (EST) e desengordurado (ESD), lactose, gordura, proteína, caseína, nitrogênio ureico do leite (NUL) e contagem de células somáticas (CCS). A análise estatística realizada foi análise fatorial e de agrupamento. O primeiro fator compreende a relação negativa da produção de leite com a raça, teor de gordura e proteína. O segundo fator compreende a relação positiva entre dias em lactação com escore de condição corporal e teor de proteína do leite. O terceiro fator é representado pela relação contrária do teor de lactose com escore de CCS, ordem de parto e ECC. No quarto fator observa-se a relação positiva entre ordem de parto e sujidade do úbere. Na análise de agrupamento foram formados três grupos que refletem as relações encontradas na análise fatorial. O monitoramento por vaca, considerando raça, ordem de parto, escore de condição corporal, dias em lactação, produção de leite, teores de gordura, proteína e lactose, escore de contagem de células somáticas e sujidade do úbere possibilitam maior controle do rebanho, facilitando corrigir possíveis deficiências pontuais de forma rápida e minimizando as perdas produtivas e econômicas.(AU)

Assuntos

RESUMO

The aim of the present study was to monitor cow milk quality and composition in two farms in the Noroeste Rio-grandense mesoregion, located in the municipalities of Palmeira das Missões and Pinhal - RS. Both herds were mixed, with animals of the Holstein (70%) and Jersey (30%) breeds. The following overall parameters were evaluated: body condition score (BCS), udder dirtiness, and calving order, and the following milk composition factors were measured: total dry extract (TDE), defatted dry extract (DDE), milk lactose, fat, and protein contents, casein, milk urea nitrogen (MUN), and somatic cell count (SCC). Multivariate statistical analysis was performed, and four factors were identified representing combinations of the measured variables. The first factor comprised negative relationships between milk production and cow breed, milk fat content, and milk protein content. The second factor comprised the positive relationships between lactation days and body condition score and milk protein content. The third factor represented the negative relationships between milk lactose content and SCC score, calving order, and BCS. The fourth factor was composed of the positive relationship between delivery order and udder dirtiness. Cluster analysis revealed that individual cows could be categorized into three groups. Monitoring the breed, calving order, body condition score, lactation days, milk production, fat, protein, and lactose contents, somatic cell counts, and udder dirtiness in cows allows greater control of the herd, allowing potential shortcomings to be rectified quickly and economic losses to production to be minimized.

Objetivou-se realizar o monitoramento por vaca em lactação referente a qualidade e composição do leite de duas propriedades rurais na mesorregião Noroeste Rio-grandense, localizadas nos municípios de Palmeira das Missões e Pinhal - RS. Ambos os rebanhos eram mistos, com animais da raça Holandês (70%) e Jersey (30%). Foram avaliados os parâmetros: escore de condição corporal (ECC), sujidade de úbere, ordem de parto e composição do leite: teores de extrato seco total (EST) e desengordurado (ESD), lactose, gordura, proteína, caseína, nitrogênio ureico do leite (NUL) e contagem de células somáticas (CCS). A análise estatística realizada foi análise fatorial e de agrupamento. O primeiro fator compreende a relação negativa da produção de leite com a raça, teor de gordura e proteína. O segundo fator compreende a relação positiva entre dias em lactação com escore de condição corporal e teor de proteína do leite. O terceiro fator é representado pela relação contrária do teor de lactose com escore de CCS, ordem de parto e ECC. No quarto fator observa-se a relação positiva entre ordem de parto e sujidade do úbere. Na análise de agrupamento foram formados três grupos que refletem as relações encontradas na análise fatorial. O monitoramento por vaca, considerando raça, ordem de parto, escore de condição corporal, dias em lactação, produção de leite, teores de gordura, proteína e lactose, escore de contagem de células somáticas e sujidade do úbere possibilitam maior controle do rebanho, facilitando corrigir possíveis deficiências pontuais de forma rápida e minimizando as perdas produtivas e econômicas.

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Animal breeding programs have used molecular genetic tools as an auxiliary method to identify and select animals with superior genetic merit for milk production and milk quality traits as well as disease resistance. Genes of the major histocompatibility complex (MHC) are important molecular markers for disease resistance that could be applied for genetic selection. The aim of this study was to identify single nucleotide polymorphisms (SNPs) and haplotypes in DRB2, DRB3, DMA, and DMB genes in Murrah breed and to analyze the association between molecular markers and milk, fat, protein and mozzarella production, fat and protein percentage, and somatic cell count. Two hundred DNA samples from Murrah buffaloes were used. The target regions of candidate genes were amplified by polymerase chain reaction (PCR) followed by sequencing and identification of polymorphisms. Allele and genotype frequencies, as well as linkage disequilibrium between SNPs, were calculated. Genotypes were used in association analyses with milk production and quality traits. Except for the DMA gene, identified as monomorphic, the other genes presented several polymorphisms. The DMB, DRB2, and DRB3 genes presented two, six, and seven SNPs, respectively. Fifty-seven haplotype blocks were constructed from 15 SNPs identified, which was used in association analyses. All the studied traits had at least one associated haplotype. In conclusion, it is suggested that the haplotypes found herein can be associated with important traits related to milk production and quality.

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RESUMO

We aimed to determine the relationship of milk yield, milk composition, and somatic cell score (SCS) with functional traits (lameness score, udder cleanliness score, udder depth, and teat end hyperkeratosis score) and physiological status (parity and days in milk (DIM) of cows housed in compost bedded pack barn system (CBP) using multivariate analysis. Data were collected in September and October of 2017 and evaluated using factor and cluster analysis. Four factors were formed, with the first factor showing the traits responsible for altering the lactose content in milk, the second factor comprising the effect of DIM, the third factor representing the teat end hyperkeratosis score, and the fourth factor demonstrating the udder cleanliness. The cluster analysis formed three clusters. Clusters 2 and 3 differed for protein and lactose content, SCS, parity, DIM, lameness score, and udder depth. Cluster 1 differed from the others, especially due to the high milk yield. Cow conformation traits and physiological status affected milk yield and composition in CBP. There is an association between udder depth, parity, and SCS with negative impact on lactose content. Parity is also associated with higher milk yield and teat end hyperkeratosis score. Cows with lower lameness score presented dirtier udders due to increased movements on the feed parlor and water troughs areas. Special attention to the improvement of the udder conformation traits, as well as management practices that reduce hyperkeratosis, are necessary to keep high yielding, healthy, and cows with higher longevity. The cleanliness in the feed parlor and water troughs area is very important to preserve milk quality and healthy cows.(AU)

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Here, we studied the composition of milk produced by a Holstein herd in the municipality of Nova Boa Vista, Rio Grande do Sul (RS), Brazil. The herd was first managed under a semi-confinement system and subsequently, in a compost bedded dairy barn system to facilitate animal management and, more importantly, family work. We monitored milk production by the herd under a semi-confinement system from January 2013 through September 2015, and then under a compost bedded dairy barn system from October 2015 through December 2017. The seasons of the year were spring (October to December), summer (January to March), autumn (April to June), and winter (July to September). Our results showed an increase in somatic cell count and total bacterial count with the change from semi-confinement to the compost bedded dairy barn system, possibly due to management factors; however, no changes were observed for any other of the variables under study, including lactose, fat, protein, and total solids. In addition, season markedly influenced milk composition and quality; thus, in winter and spring, milk was of a higher quality, whereas in the hotter months of summer and autumn fodder quality and availability, and the incidence of mastitis, as reflected by somatic cell count, affected milk quality negatively.(AU)

Objetivou-se estudar a composição do leite de um rebanho da raça Holandês no município de Nova Boa Vista - RS que era manejado em sistema semiconfinado e posteriormente evoluiu para Compost Bedded Dairy Barn (CBDB) como forma de facilitar o manejo dos animais e principalmente amenizar o trabalho da família. Os dados utilizados são referentes à composição e qualidade do leite entre os meses de janeiro de 2013 a outubro de 2015 em sistema semiconfinado e de novembro de 2015 a dezembro de 2017 em sistema confinado CBDB. As estações do ano foram consideradas da seguinte forma: Primavera (outubro, novembro e dezembro), Verão (janeiro, fevereiro e março), Outono (abril, maio e junho) e Inverno (julho, agosto e setembro). Os resultados mostraram um aumento da contagem de células somáticas (CCS) e da contagem bacteriana (CBT) com a mudança do sistema semiconfinado para o CBDB, ou seja, estes indicadores foram prejudicados quando as vacas estavam em sistema de CBDB, possivelmente em função dos fatores de manejo, porém, não havendo diferenças para as demais variáveis (lactose, gordura, proteína e EST). Além disso, as estações do ano influenciam a qualidade e composição do leite, sendo que no inverno e na primavera o leite apresentava melhor qualidade uma vez que nos meses mais quentes (verão e outono) a qualidade das forragens e a insciência de mastites (refletida na CCS) foram fatores determinantes.(AU)

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This study aimed to evaluates some physical chemical aspects of chilled raw milk that meet Brazilian quality standards in smallholder farms from southern Region of Brazil. The fat content, crude protein (CP), total solids (TS), somatic cell count (SCC), and total plate count (TPC) of the chilled raw milk from 78 smallholder farms was analyzed between Oct 2014 and Feb 2017. It was found that 96% of the samples met the Brazilian regulations for fat content, 87% for CP, and 91% for TS. The mean values of TPC and SCC were higher than the maximum limits established by Brazilian regulations. Smallholder farms from Southern Region of Brazil produce milk with an adequate standard for the main chemical indicators. However, there is an important gap in compliance with hygienic-sanitary practices, leading to high levels of chilled raw milk that does not meet the limits of Brazilian regulations.(AU)

Objetivou-se avaliar alguns padrões físico-quimicos do leite cru refrigerado em relação ao atendimento aos padrões de qualidade brasileiros em pequenas propriedades da Região Sul do Brasil. O teor de gordura, proteína bruta (PB), sólidos totais (ST), contagem de células somáticas (CCS) e contagem total em placas (CTP) do leite cru refrigerado de 78 pequenas propriedades foram analisadas mensalmente entre outubro de 2014 e fevereiro de 2017. Verificou-se que 96% das amostras atenderam às regulamentações brasileiras para teor de gordura, 87% para PB e 91% para ST. Os valores médios de CTP e CCS foram superiores aos limites máximos estabelecidos pela regulamentação brasileira. Pequenas propriedades da Região Sul do Brasil produzem leite com adequado padrão para os principais indicadores químicos. No entanto, existe uma lacuna importante no cumprimento das práticas higiênico-sanitárias, levando a altos níveis de leite cru refrigerado que não atendem os limites da regulamentação brasileira.(AU)

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