Effect of porcine reproductive and respiratory syndrome virus on subsequent Pasteurella multocida challenge in pigs

This trial was conducted to evaluate the effect of Porcine reproductive and respiratory syndrome virus (PRRSv) on a subsequent challenge with Pasteurella multocida in pigs. Sixteen, 3-4 week-old piglets, from a PRRSv and Aujeszky disease virus (ADV) free herd were used. Animals were equally and randomly allocated in four groups which were treated according the following schedule: Group I: negative controls; Group II: inoculation with only PRRSV; Group III: inoculation with PRRSV and P. multocida; Group IV: inoculation with ADV and multocida (positive controls), PRRSV and ADV were inoculated intranasally, at the doses of 10(4.6) and 10(4.5) TCID50/ml, respectively. Five days later, pigs from groups III and IV were inoculated intranasally, with two ml of a 10(9) CFU/mL suspension of equal parts of P. multocida, strains A52 and A24. No lesions were observed in piglets of group I. Microscopically, interstitial pneumonia was identified in all piglets of groups II and III and 3/4 piglets from group IV. Bronchopneumonia was detected in 3/4 of the piglets from group III and in all animals of group TV which, additionally, showed meningo-encephalitis and purulent rhinitis. Macroscopically, only piglets of groups III and IV had lung consolidation. However, much lower pneumonic scores (2.3%) were observed in group III, where 3 of 4 piglets were affected. on the other hand, all piglets of group IV showed some degree of pulmonary consolidation, with a mean score of 13.7%. Based on these results, it appears that the role of PRRSV as a initiator of secondary diseases is still undefined, but is probably mild, There was no clear interaction between PRRSV and Pasteurella multocida under the conditions and strains tested here. (C) 1997 Elsevier B.V. B.V.

Effects of dominant follicle aspiration and treatment with recombinant bovine somatotropin (BST) on ovarian follicular development in Nelore (Bos indicus) heifers

Follicle ablation has been recognized as an efficient method of follicular wave synchronization. Treatment with recombinant bovine somatotropin (BST) has been shown to enhance follicular development in <(Bos taurus)under bar>. This experiment assessed the effects of these treatments in Nelore (<(B. indicus)under bar>) heifers. Eight cycling Nelore heifers were randomly assigned to 3 different treatments. on Day 2 of a synchronized cycle (Day 0 = day of ovulation), heifers assigned to Treatments 1 and 2 received 2 mL of saline, whereas heifers assigned to Treatment 3 received 320 mg of BST. on Day 5, the first-wave dominant follicle was ablated by ultrasoundguided transvaginal aspiration in heifers in Treatments 2 and 3, and all heifers received an injection of prostaglandin on Day 11. Aspiration of the dominant follicle advanced and synchronized (P < 0.05) the day of second-wave emergence (6.9 +/- 0.1 vs. 8.4 +/- 0.4) and the day of the pre-wave FSH peak (6.0 +/- 0.0 vs. 6.9 +/- 0.4), and increased FSH peak concentrations (381 +/- 21 vs. 292 +/- 30; pg/mL; P < 0.01). Recombinant bovine somatotropin treatment caused a two-fold increase in plasma insulin-like growth factor-I (IGF-I) concentrations (P < 0.001) and resulted in a 36% increase in the number of small follicles (<5 mm; P < 0.001) compared with saline-treated heifers. In summary, in agreement with previous reports on <(B. taurus)under bar>, dominant follicle aspiration synchronized ovarian follicular development, and BST treatment increased peripheral concentrations of IGF-I in Nelore heifers. Recombinant bovine somatotropin also increased the number of small follicles, but this response appeared to be inferior to that reported for <(B. taurus)under bar>. (C) 2000 by Elsevier B.V.

Respiratory heat loss of Holstein cows in a tropical environment

In order to develop statistical models to predict respiratory heat loss in dairy cattle using simple physiological and environmental measurements, 15 Holstein cows were observed under field conditions in a tropical environment, in which the air temperature reached up to 40 &DEG; C. The measurements of latent and sensible heat loss from the respiratory tract of the animals were made by using a respiratory mask. The results showed that under air temperatures between 10 and 35 &DEG; C sensible heat loss by convection decreased from 8.24 to 1.09 W m(-2), while the latent heat loss by evaporation increased from 1.03 to 56.51 W m(-2). The evaporation increased together with the air temperature in almost a linear fashion until 20 &DEG; C, but it became increasingly high as the air temperature rose above 25 &DEG; C. Convection was a mechanism of minor importance for respiratory heat transfer. In contrast, respiratory evaporation was an effective means of thermoregulation for Holsteins in a hot environment. Mathematical models were developed to predict both the sensible and latent heat loss from the respiratory tract in Holstein cows under field conditions, based on measurements of the ambient temperature, and other models were developed to predict respiration rate, tidal volume, mass flow rate and expired air temperature as functions of the ambient temperature and other variables.

Influence of sire breed (Bos indicus versus Bos taurus) and interval from slaughter to oocyte aspiration on heat stress tolerance of in vitro-produced bovine embryos

Based on in vitro experiments, Bos indicus embryos were more resistant to heat stress (HS) than Bos taurus embryos. To increase knowledge regarding differences between Bos indicus and Bos taurus in resistance to HS, the primary objective of this study was to determine if tolerance to HS is due to the breed, origin of the oocyte, sperm, or both. Additionally, the influence of the interval between ovary acquisition (in the abattoir) and oocyte aspiration in the laboratory, on early embryo development was ascertained. Oocytes were collected from Nelore and Holstein cows in an abattoir; 4.0 or 6.5 h later, oocytes were aspired in the laboratory, and then matured and fertilized using semen from Nelore (N), Gir (GIR), or Holstein (H) bulls. Ninety-six h post insemination (hpi), embryos with >= 16 cells were divided in two groups: control and HS. In the control group, embryos were cultured at 39 degrees C, whereas in the HS group, embryos were subjected to 41 degrees C for 12 h, and then returned to 39 degrees C. Rates of cleavage, and formation of morula and blastocysts were higher (P < 0.05) for oocytes aspirated at 4.0 versus 6.5 h after ovaries were acquired. Heat stress decreased rates of blastocyst formation for all breeds (N X N; H x H; and H X GIR) and in both time intervals (4.0 and 6.5 h). However, N X N had higher cleavage rate (P < 0.05) in both time intervals when compared with H X H and H X GIR. In addition, Nelore oocytes fertilized with Nelore semen (N X N) had higher blastocyst yields (P < 0.05) in the control and HS group, when compared with the other two breeds (H X H and H X GIR). We concluded that the breed of origin of the oocyte was more important than that of the sperm for development of thermotolerance, because bull breed did not influence embryo development after HS, and in vitro early embryonic development was impaired by increasing (from 4 to 6.5 h) the interval between ovary acquisition and oocyte aspiration. (C) 2011 Elsevier B.V. All rights reserved.

Landfills as risk factors for respiratory disease in children

Objective: To investigate the relationship between exposure to a landfill site closed 6 years previously and respiratory symptoms in children aged up to 13 years.Method: This was a cross-sectional study conducted in Varzea Paulista, in the state of São Paulo, Brazil. One adult in every household in a neighborhood close to the landfill and from a randomized sample of households in another neighborhood with similar socioeconomic characteristics but no landfill were interviewed and asked about respiratory symptoms and other variables relating to children aged up to 13. A logistic regression model was used to study this relationship.Results: The likelihood of a child having respiratory symptoms was a function of -2.36 + 0.43 if the child was less than 2 years old; + 0.24 if the child lived in the landfill area; -0.67 if there was a computer at home; + 0.54 if firewood was burnt in the home in the last year; + 0.94 if the child was diagnosed with asthma; + 0.87 if the child visited a health service in the previous 30 days.Conclusion: The authors conclude that living near to a landfill closed 6 years previously may be a risk factor for respiratory disease in children.

Chest associated to motor physiotherapy acutely improves oxygen saturation, heart rate and respiratory rate in premature newborns with periventricular-intraventricular hemorrhage

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)