Las siguientes son publicaciones realizadas por los investigadores de la Universidad de La Salle en Salud y Bienestar Animal.
Temporal and spatial variability of particle-bound polycyclic aromatic hydrocabons in Bogota, Colombia
We have assessed diurnal profiles of particle-bound polycyclic aromatic hydrocarbons (pPAHs) in Bogota, Colombia using photoelectric aerosol sensors (PAS). PAS instruments were located close to a congested avenue to assess exposure to pedestrians, bike riders, drivers, and passengers. PAS signals during weekdays were significantly larger than during weekends, observing a similar pattern to traffic. During two different periods of analysis, it was found that meteorological conditions drive differences in PAS concentrations. An aethalometer was collocated with one PAS device to observe the relationship between PAS signals and black carbon (BC) concentration. We found a significant correlation between PAS signals and BC, suggesting that pPAHs and BC are products of the same source. Two PAS devices were located at different heights to assess vertical dispersion of pollutants. Our results suggest that pPAH loadings may diminish with height possibly due to a street canyon effect in the area. An assessment of exposure indicates that during rush hours, people are exposed to particulate matter enriched with pPAHs emitted from mobile sources. Measures should be implemented to reduce emission from vehicles on the road in order to protect public health.
Milk Production and Energy Indicators in Semi-housed Dairy Cows Treated With Low Doses of Recombinant Bovine Somatotropin During Transition Period
The aim of this study was to determine the effect of low doses of recombinant bovine somatotropin (rbST) on energy balance parameters and milk production in transition dairy cows on a semi-housed system. Seventy two Holstein-Frisian cows were used and allotted in: treatment group (rbST, n=36), treated from 3 prepartum to 6th pospartum week with 250 mg/14 days (d) of bST and control group (C, n=36), not treated. Blood samples were obtained during rbST treatment from both groups to determine non esterified fatty acids (NEFA), beta-hydroxybutyrate (beta HBA), cholesterol, urea and albumin concentrations and aspartate amino transferase (AST), glutamate deshidrogenase (GD) y gamma glutamil transferase (GGT) enzyme activities; body condition and live weight as well. Milk production was registered since partum to 7th postpartum week. Energy balance parameters were similar between groups (P>0.05) and milk production was higher in rbST than C (36.3 vs. 34.3 L/cow/d, P<0.05). The percentage of diseases presentation and reproductive parameters in both groups was similar (P>0.05), except for metritis being higher in control group (22.2 vs 5.4%; P<0.05). Results obtained allow to infer that the treatment of grazing dairy cows with low doses of rbST in transition period increases milk production without a detrimental effect on energy balance.
2014