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.

The aim of this study was to evaluate the mineral concentrations in the hoof horny capsule of healthy Holstein cows and cows with hoof problems associated with laminitis. Twenty-one multiparous Holstein cows with an average production of 24 L of milk/day, reared with semi-extensive nutritional management, were studied. The animals were evaluated and divided into two groups based on their locomotion score (LS, range: 0 to 4). LS greater than 2 indicated laminitis-associated lesions (lame cow group: LC), and LS = 0 indicated cows without laminitis (CWL). A sample of 30 mm2 was collected from the hoof horny capsule at the abaxial wall to evaluate the concentrations of calcium, phosphorus, zinc, and magnesium. Calcium blood concentration was also evaluated. The LC group had lower magnesium concentration (P=0.008) and showed a trend (P=0.06) for lower calcium concentration compared to healthy animals (CWL), even though all animals were normocalcemic. The concentration of other minerals did not differ between the LC and CWL group. In conclusion, the magnesium concentration in the hoof horny capsule was lower in cows with lesions associated with laminitis, while phosphorus and zinc concentrations were not affected. The relationship between hoof lesions and calcium concentration requires further investigation.

The aim of this study was to evaluate the incidence of diseases as well as metabolic and zootechnical parameters in Holstein calves maintained in individual or collective housing systems in the extreme south of Brazil. One hundred calves were included immediately after birth and monitored for 90 days. Animals were randomly divided into two groups: individual stalls group (ISG; n=50) and collective stalls group (CSG; n=50). ISG calves were individually housed in 1.2m² wood pens and received 6 L of milk/day and concentrate food and water ad libitum for 90 days. Calves in the CSG were housed in groups of up to 25 animals, in a total of two stalls containing one animal per 3 m2. CSG calves received up to 8 L of milk/day at 0-15 days, milk ad libitum at 15-40 days, 7.2 L of milk. /day at 40-60 days, and gradual weaning at 60-90 days with concentrate food and water ad libitum, using an automatic feeder. In both groups, Zootechnical parameters (weight, thoracic perimeter, height at the withers, and rump width) were measured weekly during the first 28 days and once every 15 days until weaning. Blood samples were retrieved weekly during the first 28 days. Metabolic parameters evaluated in this study were total calcium, beta-hydroxybutyrate (BHBA), free fatty acids (FFA), and glucose. The animals were monitored daily for clinical signs of diseases diarrhea and respiratory symptoms. General morbidity was higher in CSG 92% compared to ISG 74% (p<0.05). We observed increased diarrhea-related morbidity and a higher rate of recurrence in the ISG (50% and 60%, respectively; p<0.05) compared to those in the CSG (both 20%, p<0.05 between groups). The morbidity due to bronchopneumonia was higher in the CSG (92%) than in the ISG (74%, p<0.05). Recurrence of bronchopneumonia and mortality were similar between groups (p>0.05). Glucose, FFA, and BHBA concentrations were higher in the ISG (p<0.05) and total calcium higher in CSG (p<0.05). Finally, the weight and thoracic perimeter were higher in the CSG than those in the ISG, whereas the height and, rump width, at the withers was higher in the ISG than that in the CSG (p<0.05). In conclusion, animals raised in a collective system with automatic feeders exhibited less diarrhea and increased serum calcium as well as improved zootechnical development, although they had a higher incidence of bronchopneumonia.

The aim of this study was to evaluate the humoral immune response in beef heifers supplemented with mineral supplementation with or without the addition of rumen-protected methionine. Forty-eight Brangus nulliparous heifers were distributed into four experimental groups with three replications each: control group without supplementation and without vaccination (CG01), control group without supplementation and with vaccination (CG02), treatment group with mineral supplementation and vaccination (TG01), and treatment group with mineral supplementation added with protected methionine and vaccination (TG02). The animals were maintained under native pasture with access to water ad libitum and the supplementation was available in high-consumption covered troughs. A supplementation period of 60 days prior to vaccinations was adopted until the first dose of a monovalent experimental vaccine inactivated for BoHV-5 was applied as a method of stimulating the immune response to evaluate the supplementation effects. After a 21-day interval, blood samples were collected to evaluate the humoral response and the second vaccine booster dose was applied following the 21-day interval for new blood samples in order to evaluate the immune response against the two-vaccination protocol. From the beginning of the experiment, the animals were weighed on the days ?60, ?10, 0, 21, and 42 in relation to the vaccine protocol. The experimental groups did not differ for body weight, mean daily weight gain, and body condition score after 102 days of supplementation regardless of the treatment. No animals belonging to CG01 seroconverted throughout the experiment, proving that there was no introduction of the agent (BoHV) in the studied area. When vaccinated animals were compared to the CG01 control group, statistically higher levels of neutralizing antibodies (P ? 0.0001) and IgG (P ? 0.0001) were verified 21 days after the second vaccine dose. Among the animals of the three vaccinated groups, there was no difference in seroconversion and IgG production. Therefore, no benefits of mineral supplementation or enriched with protected methionine were observed for the humoral immune response of the studied animals.

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 evaluated the effect of two commercial forms of recombinant bovine somatotropin (rbST; Later® and Fast®; 500 mg) on feed variability, feeding behavior, zootechnical parameters, and milk production of Holstein cows after peak production. Eighteen cows were randomly divided into two groups and treated with injectable of rbST every 14 days for 70 days. Blood samples were collected on day 1, 4, and 7 of each cycle, to assess circulating levels of non-esterified fatty acids (NEFA). Weight and body condition score (BCS) assessments were performed. Milk yields were measured daily using the DelPro™ software (DeLaval®). Feed consumption and feeding behavior was obtained daily using automatic individual feeders (Intergado®). No difference was observed in dry matter intake (DMI) between groups (P=0.07), and no impact was noted on dietary variability (P=0.64). In addition, animals treated with rbST-Fast exhibited more frequent visits to feeders, longer time in consumption, and higher relative DMI (per percentage of live weight) (P<0.01). Animals in the rbST-Fast group produced more milk than those in the rbST-Later group (P=0.03). Furthermore, the weight of the cows was significantly different (P=0.05) between groups. The weight of the rbST-Fast animals was smaller and varied more than thot of the rbST-Later animals (P <0.01). Nonetheless, no difference was noted in BCS (P=0.30) between the groups. The animals in the rbST-Fast group had higher concentrations of NEFA than those in the rbST-Later group (P<0.01). In conclusion, behavioral and metabolic shifts that sustained greater milk production in the cows receiving rbST-Fast. Nonetheless, these shifts are likely linked to lipomobilization and not dietary variability or consumption, as evidenced by the increase in NEFA and greater weight loss in that group.

The goal of this study was to evaluate the effects of strategic insulin administration on follicular growth, progesterone production, and pregnancy rate in beef cattle. Two experiments were conducted, in experiment 1, 215 cows crossbreed cows (Bos indicus × Bos taurus) (Control Group, n = 109; Insulin Group, n = 106) were submitted to fixed-time artificial insemination (TAI) with application of 2 mg of estradiol benzoate and a vaginal device containing progesterone on day 0. On day 9, the device was removed and 0.5 mg of estradiol cypionate was administered with 12.5 mg of dinoprost and 0.25 UI kg-1 of insulin for the treated animals. On day 11, artificial insemination (AI) was performed on all animals. On days 9 and 11 according to the protocol, was evaluated follicular growth and estrus manifestation, and 30 days after AI the pregnancy rate. In experiment 2, 85 cows were utilized, including Aberdeen Angus, Hereford, and crossbreeds (Control Group, n = 49 and Insulin Group, n = 36), and were submitted to the protocol for fixed-time embryo transfer (FTET), and progesterone concentrations were evaluated. On day 0, the cows received 2 mg of estradiol benzoate and a vaginal device containing progesterone. On day 5 of the protocol, 0.150 mg of cloprostenol was administered. On day 8, the vaginal device was removed and 20 mg of purified porcine pituitary extract and 0.25 UI kg-1 of insulin was given to the animals in the treatment group, and on day 9, 1 mg of estradiol benzoate was administered. On day 17, an embryo transfer was performed and blood collection for evaluation of progesterone levels in animals submitted to FTET were collected. In experiment 1, the follicular growth rate and the pregnancy rate were similar between groups (P > 0.05) and in experiment 2, the production of P4 was not different between the animals that received the insulin application and the control group. The utilization of a single dose of insulin for beef cows did not affect the ovulatory follicular diameter, progesterone concentrations, or pregnancy rate.

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.