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The aim of this study was to evaluate the components of milk and mammary gland health of Criollo mares. A total of 12 mares coming from a farm in southern Brazil were used. Samples of milk were taken from each mare every two weeks up to 180 days of lactation. The characteristics analyzed were fat, protein, lactose, total solids, somatic cell count (SCC) and total bacterial count (TBC). In relation to the health of the udder and the milk of the mares, the SCC was 24.1 x 103cells / ml and TBC was 44 x 103CFU / ml, while the average of milk components was 0.57% fat, 1.95% protein, 6.71% lactose and 9.24% total solids. Stage of lactation and individual characteristics may influence the level of milk components. The low SCC and TBC found in the Criollo breed mares’ milk ensure the quality of their milk compared to other species.

Cattle tick fever (CTF) causes significant economic losses in the livestock sector. The pathogenic action of the hemoparasites is associated with anemia, weight loss, abortion and reduced productivity, which result with animal death. Programs to prevent CTF involve several procedures, including immunization, chemoprophylaxis and use of ectoparasiticides, together with the vector control in the environment. The objective of this study was to report an acute outbreak of CTF in a group of 157 Hereford cattle from a farm without presence of the vector, that were moved to a farm in the same state with a high tick infestation (Rhipicephalus microplus). On the day before the transportation, the animals received a chemoprophylaxis with imidocarb dipropionate (3 mg/kg, SC), which was repeated 21 days after the first application. After 42 days, some animals showed signs compatible with CTF, which was confirmed through clinical examination, necropsy, histopathological and hemoparasitological analyses. The morbidity rate was 37.6% and the mortality rate was 24.8%. Calves that were recently weaned were the group most affected with the tick fever, morbidity (100% and mortality (73%). Chemoprophylaxis in association with use of ectoparasiticides was not sufficient to control the outbreak of the disease. Resumo A “tristeza parasitária bovina” (TPB) gera importantes perdas econômicas na bovinocultura mundial. A ação patogênica dos hemoparasitas resulta em anemia, perda de peso, abortos e diminuição da produtividade, culminando, muitas vezes, em óbito dos animais. Um programa de prevenção para TPB necessita de medidas integradas, como a imunização, quimioprofilaxia e utilização de ectoparasiticidas, em conjunto com ações que visem ao controle ambiental dos vetores. Este artigo tem em vista o relato de um surto de TPB em uma fazenda de produção de bovinos de corte e com alta infestação do carrapato (Rhipicephalus microplus). A fazenda adquiriu 157 animais puros de origem, da raça Hereford, proveniente de uma fazenda sem presença do vetor. No dia anterior ao transporte, os animais receberam quimioprofilaxia com dipropionato de imidocarb (3mg/Kg/SC), repetindo-se 21 dias após a primeira aplicação. Aos 42 dias, alguns bezerros manifestaram sinais clínicos compatíveis com TPB, sendo confirmado pelo exame clínico, necropsia, análises histopatológicas e hemoparasitológicas. A morbidade foi de 37,6% (59/157), e a letalidade de 24,8% (39/157). A categoria de bezerros recém desmamados foi a mais acometida, com morbidade de 100% (52/52) e letalidade de 73% (38/52). A quimioprofilaxia associada à utilização de ectoparasiticidas foram insuficientes para evitar a ocorrência do surto da enfermidade.

The preservation of milk samples for microbiological analyses by the Brazilian Network of Milk Quality Control Laboratories requires the addition of preservatives to maintain the microbiota from the time of sample collection to the moment of analysis. The number of microorganisms can change as a result of the active ingredients and concentration of the preservative, as well as due to interactions between the preservatives, incubation time, and packaging temperature. The objective of this research was to evaluate the conservation potential of different concentrations of sodium azide and chloramphenicol on the analytical shelf life of milk samples. Two farms were selected, one with a low bacterial count and one with a high bacterial count. The milk was dispensed into sterile vials and tested after the addition of the usual concentrations of sodium azide and chloramphenicol, doubled concentrations, tripled concentrations, and as a control, without preservatives. The samples were incubated at 3 ± 1 °C, 6 ± 1 °C, and 9 ± 1 °C for 14 days and analyzed daily for their bacterial count by flow cytometry. The tripled preservative concentrations improved conservation, increasing the timespan of the analytical viability of the samples without altering the results.

This study vised to detect possible changes in chemical and cellular composition of cow’s milk at different milking sessions and to test if proportional or composite milk sampling can be used instead of separate milk analysis. Two experiments were conducted: one in cows milked thrice daily and the other one in cows milked twice daily. In both experiments, three milk samples were collected from each cow in each milking session in order to determine milk composition at each milking; to have a composite sample, i.e., a single sample from the same aliquots of milk from each milking session; and to have a proportional sample, i.e., a single sample from each milking session in a volume proportional to milk volume yielded. Fat content and fat to protein ratio were higher in the afternoon on both experiments. Protein content was larger in the afternoon on cows milked twice daily, but not on cows milked thrice daily. Lactose level was not different across the milking sessions in any of the experiments. The urea level was higher in the afternoon and evening milking on cows milked thrice daily, and in the morning milking on cows milked twice daily. Somatic cell count did not differ between milking in any experiment. No difference in milk composition was noted between proportional and composite samples on cows milked thrice or twice daily. The collection of proportional and composite samples is recommended in twice or thrice daily milking sessions so that the analysis of milk components becomes more easy and cheap. RESUMO: Este estudo visou detectar possíveis mudanças na composição química e celular do leite de vaca em diferentes sessões de ordenha, e testar se a amostragem de leite proporcional ou composta pode ser usada em vez de uma análise separada do leite. Dois experimentos foram conduzidos: um em vacas ordenhadas três vezes ao dia e outro em vacas ordenhadas duas vezes ao dia. Em ambos os experimentos, três amostras de leite foram coletadas de cada vaca em cada ordenha: para determinar a composição do leite em cada ordenha; ter uma amostra composta, isto é, uma única amostra das mesmas alíquotas de leite de cada sessão de ordenha; e ter uma amostra proporcional, ou seja, uma única amostra de cada sessão de ordenha em um volume proporcional ao volume de leite produzido. O conteúdo de gordura e a relação gordura:proteína foram maiores no período da tarde nos dois experimentos. O conteúdo de proteína foi maior à tarde nas vacas ordenhadas duas vezes ao dia, mas não nas vacas ordenhadas três vezes ao dia. O nível de lactose não foi diferente nas sessões de ordenha em nenhum dos experimentos. O nível de ureia foi maior à tarde e à noite, nas vacas ordenhadas três vezes ao dia e, pela manhã, nas vacas ordenhadas duas vezes ao dia. A contagem de células somáticas não diferiu entre as ordenhas em nenhum experimento. Não houve diferença na composição do leite entre as amostras proporcionais e compostas em vacas ordenhadas três vezes ao dia. Recomenda-se a coleta de amostras proporcionais e compostas em duas ou três sessões diárias de ordenha, para que a análise dos componentes do leite se torne mais fácil e barata.

portuguesA determinacao da qualidade do leite nas fazendas e um parâmetro mundialmente aceito e utilizado como base para os sistemas de pagamento. Os produtores modernos utilizam o conhecimento das caracteristicas do leite para adotar medidas que visam melhorar produtividade e qualidade. O objetivo do estudo foi avaliar os efeitos do ano, estacao, estagio de lactacao e numero de lactacao sobre as variaveis producao e composicao do leite de vacas Holandesas (n=148,604). A producao de leite estimada por regressao multipla foi de 25,50L/vaca/dia. O inverno foi a estacao com a maior produtividade e os maiores teores de proteina e lactose. A gordura de leite foi maior no outono em vacas primiparas e no final da lactacao. As vacas com estagio de lactacao entre 6 a 60 dias e aquelas que se encontram na segunda ou terceira lactacao apresentaram a maior produtividade. A concentracao de lactose correlacionou-se positivamente com a producao de leite. O escore das celulas somaticas correlacionou-se negativamente com a produtividade e com a concentracao de lactose. As variacoes mais importantes nas caracteristicas do leite ocorrem entre estacoes, estagios de lactacao e numero de partos. A saude da glândula mamaria ainda e o maior desafio a superar. Palavras-chave: qualidade do leite; numero de lactacoes; sazonalidade; estagio de lactacao EnglishWorldwide, milk analysis is an satisfactory measurement of milk quality on dairy farms. Milk composition is the base for payment systems, so knowledge of its characteristics at different periods is essential for modern dairy producer. The aim of the study was to evaluate the effects of year, season, stage of lactation, and lactation number on variations in milk yield and composition of Holstein cows (n=148,604). Milk yield estimated by multiple regression was 25,50L/cow/day. Winter was the season with the highest milk yield and the highest protein and lactose content. Milk fat was highest in the fall, in cows in late lactation and also in primiparous cows. Lactating cows from 6 to 60 days in lactation and those in 2nd or 3rd lactation showed the highest milk yield. Lactose concentration was positively correlated with milk yield. Somatic cell score was negatively correlated with milk yield and with lactose concentration. Most important variations in milk characteristics occur among seasons, lactation stages and parities. Mammary gland health is yet the greatest challenge to be overcome. Key words: milk quality; lactation number; seasonality; stage of lactation

The intensification of the use of artificial insemination in the swine industry has increased the interest to develop proper conditions to store semen better for longer periods of time without affecting its fertility. Trolox is a vitamin E analog with antioxidant property to prevent oxidative stress. Therefore, the objective of this study was to evaluate the Trolox antioxidant capacity on boar semen during storage period (86 h) at 15°C. For that, semen samples from 5 different boars were collected and diluted with a Long-Term (LT) extender with and without the addition of Trolox in a concentration of 50 µM. The sperm motility, oxidative stress and antioxidant protection were measured in those samples during an 84 h storage time. Our results indicated that Trolox was able to minimize the loss of sperm motility after 24 h of storage. The storage time was positively correlated with TBARS production. However in the presence of Trolox, after 12 h, TBARS content were significantly lower than those of sperm cells stored with LT diluent only. The concentrations of Non-Protein SH groups (NPSH), after 36 h of storage, were lower in sperm cells stored only with LT diluent when compared to the group supplemented with Trolox. Catalase and Superoxide Dismutase activities were decreased after 48 h storage at 15°C in both groups (with or without Trolox). Spontaneous spermatozoa ROS formation was high in viable swine sperm during the LT storage period in samples without Trolox. In conclusion, LT diluent with the addition of antioxidant as Trolox can reduce the oxidative stress in sperm cells, which could be used to protect spermatozoa against oxidative damage, preventing motility losses in swine semen.

We designed an experiment to determine the concentrations of a marker of lipid peroxidation in erythrocytes of horses submitted to jumping competitions. Erythrocytes of exercised horses showed a significant increase in the concentration of thiobarbituric acid-reactive species content immediately after exercise ( P P P P P

Estrus synchronization with progesterone is commonly used in farms with better reproductive control. Free radicals production, i.e. oxidative stress, is associated with progesterone levels. The oxidative stress is responsible for aggression to the cellular membrane, leading to a lise and lipoperoxide formation. In this work, the antioxidant compensatory effect (Vitamins C and E) associated with the exogenous progesterone implant (P4), used in estrus synchronization protocols in cattle, was evaluated. Twenty-five cows were randomly selected in 5 different groups: 1) control without P4, 2) control with P4, 3) P4 + vitamin C and E, 4) P4 + vitamin E, 5) P4 + vitamin C. The lipid lipoperoxidation was measured trough Thiobarbituric acid reactive substances (TBA-RS) and Glutatione Peroxidase enzyme (GSHpx) at days 0 and 7 of the estrus synchronization protocol. The use of vitamin E, in this experiment, showed a better pregnancy rate, however, the results must be validated before orienting the use of the vitamin in cows synchronized with P4. KEYWORDS: Antioxidants, cows, oxidative stress, pregnancy rate, progesterone.

Para avaliar a influência da suplementação com selênio e vitamina E sobre o perfil proteico e metabolismo oxidativo de cordeiros infectados experimentalmente pelo Haemonchus contortus, trinta cordeiros fêmeas foram distribuídos em quatro grupos: G1 (n=10): animais infectados; G2 (n=10): infectados e suplementados; G3 (n=5): controle; e G4 (n=5): não infectados e suplementados. Os grupos 1 e 2 receberam 500 larvas de H. contortus (L3), via oral, por um período de 20 dias, com intervalo de dois dias entre as doses. A suplementação nos grupos 2 e 4 foi realizada no dia zero, com 0,1mg kg-1 de Selenito de sódio (1,67%) e com 2.000UI de vitamina E por via intramuscular (IM). Somente a vitamina E foi reaplicada no dia 30. As coletas de sangue para determinação do perfil proteico (proteína total, albumina, alfa, beta e gamaglobulina) e metabolismo oxidativo (espécies reativas ao ácido tiobarbitúrico-TBARS e a enzima glutationa peroxidase (GSPX) foram realizadas nos dias zero, 20, 30, 45, 60 e 80. OPG foi quantificado nos dias 0, 20 ,45 e 80. Em relação aos valores de proteínas totais, albumina, betaglobulina e gamaglobulina, as principais diferenças foram observadas quando os grupos parasitados foram comparados com o grupo somente suplementado; e este manteve valores mais elevados. Conclui-se que não há influência da suplementação com selênio e vitamina E no perfil proteico e metabolismo oxidativo quando os cordeiros se encontram severamente parasitados por H.contortus.

Background: Intoxication caused by Senecio sp is characterized by irreversible damage to liver cells and may be associated with oxidative stress. Objectives: The aim of this study was to evaluate the effects of intoxication by Senecio sp on lipoperoxidation, antioxidant defenses, and the osmotic resistance of erythrocytes in cattle. Methods: Blood samples from 30 intoxicated animals (group 1) and 30 healthy animals (group 2) were analyzed. The diagnosis of poisoning by Senecio sp was based on histopathologic lesions verified through hepatic biopsy. The following biochemical parameters of oxidative stress in the erythrocytes were determined: thiobarbituric acid-reactive substances (TBARS), copper–zinc superoxide dismutase (CuZnSOD) activity, and nonprotein sulfhydryl (NPSH) groups. Erythrocyte osmotic fragility also was evaluated. Results: TBARS concentration and CuZnSOD activity were significantly (P < .001) higher in group 1 when compared with group 2. The concentration of erythrocyte NPSH groups was significantly (P < .03) lower in group 1 when compared with group 2. Osmotic fragility was more pronounced in the erythrocytes of group 1 when compared with group 2 (P < .001). Conclusions: The results of this study indicate that poisoning by Senecio sp causes an increase in lipoperoxidation, oxidation of NPSH groups, and consequently, oxidative stress in bovine erythrocytes that may contribute to hemolysis. These findings may contribute to a better understanding of the mechanisms involved in cell damage in animals intoxicated by Senecio sp.

This study aimed to determine the impact of different post-partum disorders on milk yield and composition. One hundred and fifteen Holstein cows from a commercial dairy farm located in the state of Rio Grande do Sul in southern Brazil were monitored up to 62 days post-partum. During this period, body condition score evaluation and animal clinical examination were conducted. Percentages of fat, protein, and lactose, as well as somatic cells score, were determined in milk samples. The AST activity and concentrations of NEFA, calcium, and BHBA, were analyzed in blood samples. The occurrence of clinical disorders was identified in 30 (26%) cows. Subclinical disorders were identified in 64 (56%) cows. Only 21 (18%) cows did not suffer any kind of disorder within the studied period. In this study, no significant differences were found in milk production, protein, and somatic cell count in clinical, subclinical, and healthy cows. Milk fat and the fat: protein quotient (F:P) were higher in cows with clinical disorders and the 6 to 21 days in milk, and lactose were lower in cows with clinical disorders and the 22 to 42 days in milk (P