Maristela Silveira Palhares

Detection of A/B toxin and isolation of Clostridium difficile and Clostridium perfringens from foals

REASONS FOR PERFORMING THE STUDY Toxin detection and screening could contribute to knowledge of the transmission patterns, risk factors and epidemiology of Clostridium difficile and Clostridium perfringens. OBJECTIVE To isolate C. difficile and C. perfringens and to detect A/B toxins in faecal samples from diarrhoeic and nondiarrhoeic foals. STUDY DESIGN Cross-sectional observational study. METHODS A total of 153 samples from foals were collected: 139 samples from farms and 14 samples from diarrhoeic foals admitted to a veterinary hospital. The A/B toxins were detected by cytotoxicity assay. All suspected colonies of C. perfringens were subjected to polymerase chain reaction for detection of the major toxin genes (α, β, ε and ι) and for detection of β2-, NetB- and enterotoxin-encoding genes. Furthermore, C. difficile and C. perfringens isolates were evaluated for in vitro antimicrobial susceptibility. RESULTS Seven of 153 (4.6%) samples, all from diarrhoeic foals, were positive for C. difficile A/B toxin. Of these, 5 of 14 (35.7%) were from hospitalised foals, and only 2 of 63 (3.2%) diarrhoeic foal samples were from farms (P = 0.002). Clostridium perfringens was isolated from 31 (20.3%) foals, of which 21 of 76 (27.6%) were diarrhoeic and 10 of 76 (13.2%) were nondiarrhoeic, demonstrating a difference between these 2 groups (P = 0.045). Only 4 strains were positive for the β2-encoding gene (cpb2). All C. difficile and C. perfringens isolates were susceptible to metronidazole and vancomycin. CONCLUSIONS The present report highlights the need for laboratory diagnostics to differentiate C. difficile-associated infection in foals from other causes of diarrhoea to facilitate adequate antimicrobial therapy. POTENTIAL RELEVANCE More studies are needed to clarify the role of C. perfringens as a primary agent of diarrhoea in foals.

Afecções mais freqüentes do aparelho locomotor dos eqüídeos de tração no município de Belo Horizonte

The most common conditions of the musculoskeletal system of draft equidae in the city of Belo Horizonte were determined. Fifty-eight animals (42 horses and 16 mules) were randomly examined, being 31 males and 27 females. Diagnosis was based on history, clinical and radiological examinations. The frequency observed for tenosynovitis in the fore and hindlimbs was 55.2%, 81.0%, for tendinitis in the forelimbs, 58.6% for tendinitis in the himblimbs, and 77.6% for suspensory ligament desmitis in the forelimbs. The results showed 13.8%, 12.1%, 27.6% and 12.1% of osteoarthritic lesions for distal interphalangeal joint of fore and hindlimbs and proximal interphalangeal joint of fore and hindlimbs, respectively. In the fetlock joints of the forelimbs, the incidence was 41.4%, and 39.7% in the hindlimbs. The incidence increased in the carpal joints, reaching 62.1% and it was even higher in the tarsal joints, reaching 96.6%. Findings in soft tissues indicated an overloading of both suspensory and flexor apparatus. Osteoarthritis was a common finding in draft equine, especially in tarsal joint. In both cases, the activity developed by those animals seems to be the main related cause.

First evidence of autochthonous cases of Leishmania (Leishmania) infantum in horse (Equus caballus) in the Americas and mixed infection of Leishmania infantum and Leishmania (Viannia) braziliensis.

This study reports the first evidence of infection by Leishmania infantum in Equus caballus in Americas and the first mixed infection of L. infantum/Leishmania braziliensis on this mammalian species in the world. The diagnoses was based on presence of parasites in lesions and bone marrow aspirates, their identification by using specific primers for L. infantum and L. braziliensis complexes and also serological methods IFAT and ELISA. The analysis of the PCR products suggested mixed infection in three animals. Further studies involving equine leishmaniasis are carrying out in order to clarify the dynamic of Leishmania sp. in this mammalian specie and their role in the transmission of those parasites in urban endemic area of Belo Horizonte, Minas Gerais State, Brazil.

Efeito da base genética materna e da estação de parição sobre variáveis produtivas de fêmeas primíparas Holandês x Zebu

Productive variables of 78 crossbred Holstein x Zebu primiparous cows of Gir or Guzera maternal genetic basis, calved in the dry or rainy season were evaluated using the GLM procedure of the SAS. The calving season affected the weight at calving (WC), body condition score at calving (BCS), service period (SP) and calving interval (CI). The WC and BCS were higher (P<0.05) por cows calved in the dry season, 475.19±39.81kg and 4.07±0.44, than in the rainy season, 420.67±37.80kg and 3.62±0.37, respectively. The SP and CI were shorter (P<0.05) for cows calved in the dry season, 132.02±91.94 days and 13.90±3.06 months, than cows calved in the rainy season, 190.07±77.27 days e 15.84±2.58 months, respectively. The Gir based cows had higher milk yield, longer lactation period and higher milk yield per day of calving interval than the Guzera based cows, respectively, 2276.15±656.47kg, 306.08±46.55 days, 5.06±1.38kg/day for the Gir and 1733.74±678.41kg, 265.62±67.11 days, 4.37±1.68kg/day for the Guzera based cows.

Parâmetros reprodutivos de cabras Toggenburg inseminadas com sêmen resfriado, após diluição em meio à base de gema de ovo

The conception rate, the prostaglandin response, the estrus duration, the reproductive class, and the mucous of goats inseminated with semen diluted in egg yolk extender and cooled at 5oC, for 12 or 24 hours were evaluated. Sixty-two female goats and two sexually mature Toggenburg bucks were used. The females received two doses of 22.5µg of prostaglandine F2α, at 10-day intervals. After the first injection, the estrus was monitored three times a day (6:00, 12:00, and 18:00h), with a buck teaser. Only one insemination was used. The percentages of animals that showed estrus after the first and the second injection of PGF2α were 85.5% and 88.7%, respectively. The average intervals from first and second PGF2α injection to estrus were 41.04±20.32 and 45.67±9.28h, and the estrus durations for both injections were 40.02±15.96 and 32.24±12.09h, in this order. The interval from the PGF2α injection to the beginning of the estrus was longer (P 0.05) the conception rate. The mucous observed at the insemination time influenced (P<0.05) the fertility of inseminated goats, with the striated aspect associated to higher fertility.

Concentração plasmática de progesterona em novilhas receptoras submetidas à administração de rbST, GnRH ou hCG no quinto dia do ciclo estral

The ability of different hormones administered on day five of the estrous cycle to induce the ovulation of the first wave dominant follicle (FWDF) and to form an accessory corpus luteum (CLa), and the respective effects on plasma progesterone concentrations were studied in recipient heifers. Fifty-two crossbred Holstein-Zebu heifers were randomly assigned to four treatments: T1-control, T2-subcutaneous administration of 500mg of rbST, T3-intramuscular administration of 100mg of GnRH and T4-administration of 3000IU of hCG (1000IU endovenous and 2000IU intramuscular). Transrectal palpation was performed on days 5, 13 and 60 to check original corpus luteum, CLa and pregnancy, respectively. CLa formation was as follow: T1-0/12 (0.0%), T2-0/13 (0.0%), T3-5/12 (41.7%) and T4-10/15 (66.7%), being T1 and T2 different from T3 and T4 (P<0.05). Plasma progesterone concentration (ng/ml) was determined by radioimmunoassay from blood samples collected from jugular vein on days 5, 13, 17 and 21. Thirty-two embryos, T1=8, T2=8, T3=7 and T4=9, were transferred to recipients at day 7. Only heifers not receiving embryos were collected on days 17 and 21. Differences on plasma progesterone concentration were observed only on day 13. The values were T1=5.01± 1.04, T2=4.80± 1.26, T3=6.42± 1.47 and T4=11.16± 2.79, being T3 different from T1, T2 and T4, and T4 different from T1, T2 and T3 (P<0.05). No differences between pregnancy rates, T1=37.5% (3/8), T2=62.5% (5/8), T3=28.6% (2/7) e T4=33.3% (3/9), were found. These results showed that the FWDF on day 5 is capable to respond to GnRH-analog and hCG, to ovulate and forme an accessory corpus luteum, which allows for an endogenous increase in plasma progesterone concentration in heifers on day 13 of the estrous cycle, the critical period for establishment of pregnancy in bovine.

Taxa de concepção de cabras inseminadas com sêmen caprino resfriado a 5ºC, por 12 ou 24 horas, em meio diluidor à base de gema de ovo

The fertilizing capacity of goat semen cooled in egg yolk diluent at 5oC, for 12 or 24 hours was evaluated. Sixty-two Toggenburg does and two sexually mature Toggenburg bucks were used in a fatorial treatment combination (two bucks and two storage periods). The semen was diluted in 2.5% Tris-frutose-egg yolk; envased in 0.25mL plastic straws, with 150x106 mobile spermatozoa; and cooled at 5oC for 12 or 24 hours. The females received two doses of 22.5µg of prostaglandine F2α, at each 10-day intervals in order to synchronize the estrous. From the first PGF2α injection, estrous occurrence was monitored three times per day. Only one insemination was used, using the cervix fixation method, 12 hours after the estrous onset. The means of motility and strength, 12 (TI) and 24 hours (TII) after semen cooling at 5oC, were 66.14±0.11% and 62.50±0.05%, and 3.46±0.61 and 3.27±0.50, respectively. Neither the sire nor the period of semen influenced (P>0.05) the conception rate of the does, which was 49.1%.

Adequação de um sistema de hemodiálise em eqüinos

Hemodialysis adequacy was studied in four groups with six horses in each: the treatments: group I animals were submitted to unilateral central venous catheter (control group); group II animals were submitted to unilateral central venous double lumen catheter and one six-hour session of hemodialysis; group III horses were submitted to unilateral central venous double lumen catheter and to two six-hour session of hemodialysis, and group IV horses were submitted to bilateral central venous mono lumen catheter and to one six-hour session of hemodialysis. Xilazine 10% (0.4mg/kg) and acepromazine 2% (0.008 mg/kg) were iv administrated for sedation. Two hollow fiber, 1.8m2 low flux polyssulfone hemodialysis apparatus were used in a connected serie. The mean blood flux was 319.18±97.41ml/min with a dialisate flux of 500ml/min. Anticoagulation was performed with sodium heparin, 100UI/kg for priming at the dose of 53.86±18.61UI/kg/h. Anticoagulation monitoring was performed by clotting time, protrombin time, tromboplastin activated time, and platelet number. Decrease in platelet number was detected in groups submitted to dialysis. The best vascular access was performed with double lumen catheter and the hemodialysis may be used in equine practice, with high performance dialyze used in six- hour session.

Indução do estro no pós-parto em vacas primíparas Holandês-Zebu

The experiment was carried out to evaluate the effect of two ranges of body weight and norgestomet treatment on the reproductive parameters of postpartum crossbred Holstein-zebu cows. Sixty four primiparous cows were randomly allocated to four treatments 40 days after calving: group I - cows with body weight ranging from 390 to 458kg and norgestomet treated; group II - cows with body weight ranging from 464 to 562kg and norgestomet treated; group III - cows with body weight ranging from 390 to 458kg (control); and group IV - cows with body weight ranging from 464 to 562kg (control). Progestagen auricular implants were mantained during 10 days and the cows were mated to bulls submitted to breeding soundness evaluation. Animals from treatment II showed estrus earlier than animals of the others treatments (II: 64.4; I: 109.4; III: 143.2 and IV: 105.1 days; P 0.05). The hormonal treatment and the body weight did not affect the total and daily milk yield, and length of lactation (P>0.05). Progestagen treated, heavier and better body condition scored animals had shorter open days, and returned to postpartum ovarian ciclicity faster than lighter animals.

Estádios de desenvolvimento embrionário de vacas zebuínas superovuladas

This study was carried out with the objective of reporting the developing stages of embryos collected from superovulated zebu cows. Twenty-six zebu cows of Nelore (16), Polled Nelore (3), Gir (4), Brahman (2) and Guzera (1) breeds were superovulated with 350IU of FSH, divided into eight decreasing doses administered each 12 hours, starting on day 10 of the estrous cycle (estrous = day 0). Seven-day embryos were collected non-surgically and evaluated at microscopy to determine the grade and stage of development. A total of 135 viable embryos were collected, being 68.2% (92/135) Nelore, 12.6% (17/135) Pooled Nelore, 11.1% (15/135) Gir, 5.2% (7/135) Brahman and 3.0% (4/135) Guzera. Embryos were classified according to quality as grade I, 51.1% (69/135), grade-II, 43.7% (59/135), grade-III, 4.4% (6/135), and grade-IV, 0.7% (1/135), and according to developmental stage in morulae, 3.7% (5/135), young blastocyst, 16.3% (22/135), blastocyst, 37.0% (50/135), expanded blastocyst, 42.2% (57/135), and hatched blastocyst, 0.7% (1/135). These results showed the predominance of advanced developing stages (blastocyst, expanded blastocyst and hatched blastocyst) witch represented 80% of the total of embryos.