Suchergebnisse

A bovinocultura brasileira enfrenta diversos desafios, dentre esses, as doenças transmitidas por vetores que geram prejuízos significativos pela ampla disseminação no país. As técnicas moleculares são mais sensíveis na identificação de animais persistentemente infectados. Dessa forma, o objetivo deste trabalho foi compilar dados referentes à ocorrência de Anaplasma marginale, Babesia bigemina e Babesia bovis, causadores da tristeza parasitária bovina (TPB), detectados por técnicas moleculares, identificando lacunas e oportunidades para futuras pesquisas no Brasil. Para isso, foi conduzida uma revisão sistemática, onde os principais critérios de inclusão foram: estudos realizados com amostras do Brasil; utilização de amostras de bovinos naturalmente infectados; dados exatos sobre número ou percentual de animais positivos; número de amostras por rebanho ≥ 10; e informações, pelo menos, do estado de origem das amostras. Ao todo, 38 estudos foram incluídos na revisão, utilizando-se de técnicas de PCR convencional (multiplex PCR, PCR, nPCR e snPCR) e PCR quantitativa e semiquantitativa (qPCR e HRM). As faixas de ocorrência para as espécies foram: 35 a 98,78% para A. marginale; 8,19 a 86,25% para B. bigemina; e de 7,32 a 95,47% para B. bovis. Os maiores percentuais de ocorrência de A. marginale e B. bovis foram no estado de RO, e de B. bigemina foi no estado de SP. Apesar da quantidade de dados encontrados, ainda são evidentes inúmeras oportunidades de direcionamento para futuras pesquisas, principalmente no que diz respeito ao uso de técnicas moleculares e quantificação das perdas nos rebanhos de maior ocorrência da TPB.

This study assessed the effect of subclinical mastitis on the productivity and inflammatory markers in Jersey dairy cows. Blood, milk, and milk yield data were collected from 59 Jersey dairy cows reared under a semi-extensive system. Milk samples were collected from individual collectors and evaluated for their somatic cell count (SCC), lactose (Lact), protein, fat, total and defatted dry extracts (DDE), casein, freezing point, and milk urea nitrogen (MUN) levels. After milking, blood was collected by puncturing the coccygeal arteriovenous complex. In the serum samples, the inflammatory biomarkers paraoxonase-1, albumin, and total plasma protein levels were analyzed using colorimetric methods. Samples of the entire diet provided and pastures were submitted for bromatological analysis. Additionally, the body condition score, number of lactations, milk yield, days of lactation, calving interval, number of inseminations until conception, calving-conception interval, and days of pregnancy were analyzed. The cows were categorized based on their SCC into a subclinical mastitis group (SubG), with SCC levels greater than or equal to 200,000 cells/mL, and a control group (CG), with SCC levels below 200,000 cells/mL. Blood metabolic variables, milk quality, and milk production data were analyzed using multivariate regression, analysis of variance, and logistic regression using the SAS® program. The multivariate regression analysis revealed that several markers, such as Lact, total protein, and casein, influenced milk composition, predicting over 97% of the data. The SubG showed lower concentrations of Lact (4.37 vs. 4.47%; P = 0.0002), MUN (20.55 vs. 23.85 mg/dL; P = 0.02), and DDE (9.24 vs. 9.50%; P = 0.02) compared with the CG; moreover, animals in the SubG had a higher number of lactations compared with those in the CG (4.30 vs. 2.69; P = 0.0039). Cows with a Lact content lower than 4.265% (quartile 25%), compared with those with Lact content greater than 4.565% (quartile 100%), were 52 times more likely to have subclinical mastitis. Jersey dairy cows with subclinical mastitis have lower Lact, urea, and defatted dry extract levels in their milk as well as a higher number of lactations. Therefore, Lact levels in milk serve as a good diagnostic marker of subclinical mastitis in Jersey cows. Subclinical mastitis in Jersey dairy cows did not decrease milk yield nor effect reproductive performance.

This study examines rumen-fluid parameters and the biochemical profile of feedlot sheep supplemented with a commercial product composed of yeast culture and enzymatically hydrolyzed yeast during an abrupt change of diet. Eight sheep at 30 months of age, with an average weight of 40.2 ± 3.4 kg, were housed in individual stalls where they received the same diet twice daily, which was formulated according to the National Research Council [NRC] (2007). The animals were divided into two groups, namely, supplemented with Saccharomyces cerevisiae (SG, n = 4) and control (CG, n = 4). The experiment consisted of three periods: the first (seven days) consisted of an acclimation to the roughage-only diet; in the second period (five days), the animals of SG started to receive supplementation; lastly, in the third period (five days), all animals underwent a sudden change of diet, which was characterized by an alteration from 100% roughage to a 50:50 ratio (roughage:concentrate) without prior adaptation. Blood samples were collected to evaluate albumin, aspartate amino transferase, calcium, gamma glutamyl transferase, globulins, glucose, magnesium, potassium, sodium, total plasma proteins and urea. Rumen fluid was harvested to evaluate physical aspects. Supplementation increased the protozoa count; the rate of sedimentation and fluctuation remained within the physiological parameters; and total plasma proteins and globulin decreased. Therefore, the yeast appears to be a promising alternative for reducing the deleterious effects of an abrupt change of diet.