Effects of Solar Radiation on the Radiometric Properties of Biodegradable Films for Agricultural Applications

Research was carried out in order to evaluate the modifications of the radiometric properties of innovative biodegradable films exposed to the climatic agents. The biodegradable materials were used for crop protection in the cultivation of strawberry plants in Southern Italy during the winter and spring seasons. Low tunnels were covered using four different transparent biodegradable films. Climatic data of the site and microclimatic parameters inside the low tunnels were measured during the cultivation period. Laboratory tests were carried out on the samples of films gathered during the field trial in order to evaluate the effects of the solar radiation on the radiometric characteristics. A decrease of up to 13% of the transmissivity in the photosynthetically active radiation range was identified for the materials exposed during the field trial. The variation of the radiometric properties, as a function of the cumulative solar radiation falling on the covering material, showed that the reduction of the transmissivity coefficient in the photosynthetically active radiation range occurred mainly up to 500 MJ m⁻² of cumulative solar radiation, corresponding to 10% of the yearly local value. Besides equations relating the photosynthetically active radiation transmissivity coefficient and the cumulative solar radiation were defined by means of linear regression processed on the experimental data.     

Comparison Between a γ-IFN Assay and Intradermal Tuberculin Test for the Diagnosis of Bovine Tuberculosis in Field Trials in Brazil

Bovine tuberculosis is a major problem in Brazil. The intradermal tuberculin test is the standard test for detection of bovine tuberculosis in Brazil but can lack both sensitivity and specificity. The purpose of this study was to compare a bovine γ-IFN assay with the tuberculin test under field conditions in Brazil. A total of 1632 animals from 13 dairy farms were tested using the single cervical tuberculin test (SCTT). Among those animals, about 15% of each herd, 220 in total, represented a high-risk group and were selected to be tested using the γ-IFN test. Of the 1632 animals tested, 207 presented significant reactions representing 12.7% of the cattle studied. In the selected group the number of animals positive by the γ-IFN assay was 126/220 (57.3%) and the total number of reactive cows on SCTT was 106/220 (48.2%). The real number of infected cattle, following standards, was 120/220 (54.5%). From these results the relative sensitivity rate of γ-IFN test was 100% including the false-positive results and 88.3% for the SCTT — a significant (P < 0.01) difference in favour of the γ-IFN test of 11.7%. The γ-IFN assay also identified some positive animals 60–120 days earlier than the SCTT. In conclusion, we believe that the γ-IFN assay can be used alone or in combination with the SCTT, as a valuable tool for the control of bovine tuberculosis in the Brazilian national herd.     

Anatomicohistological Characteristics of the Female Genital Organs of the White‐lipped Peccary (Tayassu pecari) in the Peruvian Amazon

This study examined the anatomical and histological characteristics of the genital organs of the female white‐lipped peccary in the wild in different reproductive stages, collected by rural hunters in the North‐eastern Peruvian Amazon. Mean ovulation rate was 2.12 ± 0.83 follicles and litter size was 1.78 ± 0.41 embryos or fetuses per pregnant female, resulting in a low rate of reproductive wastage, averaging 0.33 ± 0.66 (16.04%) oocytes or embryos per pregnancy. The ovulation rate and the anatomical performance of the uterus could limit the prolificacy of this species. Females in follicular phase showed follicular waves suggesting the synchronous growth of a cohort of follicles. Different uterine and vaginal epithelium features changed in accordance with the reproductive state of the female. Pregnant females and females in the luteal phase presented a significant proliferation of endometrial uterine glands, characterized by hyperplasia and branching of endometrial glands, and increase in the proportion of cervical epithelial cells with periodic acid‐schiff (PAS)‐positive granules compared with that in females in the follicular phase. Females in the follicular phase showed a more developed vaginal epithelium (in thickness and in layer composition) than females in the luteal phase and pregnant females.     

Physicochemical and ecotoxicological evaluation of estuarine water quality during a dredging operation

Purpose

Most of the information concerning the effects of contaminated sediments on estuarine organisms deals with the impacts of bed forming sediments. The ecotoxicological potential at the time of a dredging operation is more difficult to assess, and few studies have dealt specifically with resuspended contaminated sediments. The aim of this study was to determine whether release of contaminants through sediment resuspension during a dredging operation in the Itajaí-açu estuary (Brazil) changed the water quality classification and had an ecotoxicological impact on the near-field water column during the critical moment of this operation.

Materials and methods

Waters from two sites (control and dredged sites) were analyzed for physicochemical parameters before, during, and after a dredging operation. In parallel, a short-term, sensitive battery of biotests (bacteria, algae, and daphnids) was performed with water samples before and during this operation according to the ISO bioassay protocols.

Results and discussion

No short-term toxicity was observed with waters collected before or during the dredging operation. The results showed that desorption of contaminants from suspended particles of sediments with a low level of contamination during a dredging operation lowered the water quality in the near-field water column but that this did not promote significant acute toxicity effects on the organisms tested.

Conclusions

More detailed studies are needed (e.g., the question of the reliability of biotests under turbulent, particle-rich conditions) to fully understand this complex issue regarding water column ecotoxicity during the whole dredging operation and to support decisions on the management of dredging activities.

     

Effects of the radiometric properties of innovative biodegradable mulching materials on snapdragon cultivation

Research on the application of innovative biodegradable materials for substrate mulching in greenhouse floricultural cultivation was carried out in Southern Italy. A transparent biodegradable film and a transparent biodegradable spray coating were compared with a commercial transparent low density polyethylene film. The biodegradable film was a starch based extruded material, the sprayed coating was created from a polysaccharide solution. The materials were used to mulch the peat and perlite growing media contained in trays during snapdragon cultivation in order to increase the substrate temperature and hasten early growth. The climate variables inside and outside the greenhouse and the growing medium temperature under the mulching materials were recorded. Biometrical data, such as mean blooming time, plant height and spike length, were collected. The laboratory radiometric tests showed that the biodegradable mulching materials had a lower solar transmissivity in comparison to the low density polyethylene film. The capacity to reduce the long wave infrared thermal losses was higher for the biodegradable mulches: the long wave infrared transmissivity coefficient was 53.9% for the low density polyethylene film, 12.1% for the biodegradable film and 8.2% for the spray coating. The increase of the growing medium temperature allowed the harvest of the snapdragon grown in the mulched trays 7 days before that of the flowers grown in the un-mulched trays. At the end of the crop cycle the disposal of the biodegradable mulching materials was carried out fragmenting and mixing them with plant residue and the growing medium. The residue biodegraded in almost 1 month for the spray coating and in about 12 months for the biodegradable film.     

Comparison between a gamma-IFN assay and intradermal tuberculin test for the diagnosis of bovine tuberculosis in field trials in Brazil.

Bovine tuberculosis is a major problem in Brazil. The intradermal tuberculin test is the standard test for detection of bovine tuberculosis in Brazil but can lack both sensitivity and specificity. The purpose of this study was to compare a bovine gamma-IFN assay with the tuberculin test under field conditions in Brazil. A total of 1632 animals from 13 dairy farms were tested using the single cervical tuberculin test (SCTT). Among those animals, about 15% of each herd, 220 in total, represented a high-risk group and were selected to be tested using the gamma-IFN test. Of the 1632 animals tested, 207 presented significant reactions representing 12.7% of the cattle studied. In the selected group the number of animals positive by the gamma-IFN assay was 126/220 (57.3%) and the total number of reactive cows on SCTT was 106/220 (48.2%). The real number of infected cattle, following standards, was 120/220 (54.5%). From these results the relative sensitivity rate of gamma-IFN test was 100% including the false-positive results and 88.3% for the SCTT--a significant (P < 0.01) difference in favour of the gamma-IFN test of 11.7%. The gamma-IFN assay also identified some positive animals 60-120 days earlier than the SCTT. In conclusion, we believe that the gamma-IFN assay can be used alone or in combination with the SCTT, as a valuable tool for the control of bovine tuberculosis in the Brazilian national herd.     

Evaluation of an ELISA-PPD for the diagnosis of bovine tuberculosis in field trials in Brazil.

Bovine tuberculosis is a major health problem in Brazil. The intradermal tuberculin test is the standard test for its detection, but it can lack both sensitivity and specificity. The purpose of this study was to evaluate a bovine enzyme-linked immunosorbent assay- (ELISA - PPD) under field conditions in Brazil. A total of 1632 animals from 13 dairy farms were tested with the intradermal tuberculin test (ITT). Two hundred and seven cows gave a positive reaction, which represents 12.7 per cent of the cattle studied. The sensitivity and specificity rates to ITT were 87.7 per cent and 95.2 per cent, respectively. From the 1632 animals 15 per cent of each herd (220 in total) were selected to be tested by the ELISA. Differences between mean optical density (OD) of the control group, ITT -positive and ITT -negative groups were all significant (P<0.01). The sensitivity rates to ELISA - PPD were 86.7 per cent, while specificity was 90.6 per cent. The use of ELISA - PPD is suggested for situations where the investigation of the whole herd is more important than the individual testing of each cow. In addition, the ELISA - PPD can also be helpful when a collective diagnosis is desired to elucidate clinical suspicions of disease, or in the first steps of a control program, for identification of foci.     

Influence of mass and volume of ruminal contents on voluntary intake and digesta passage of a forage diet in steers.

To assess the influence of volume and mass of ruminal contents on voluntary intake and related variables, five ruminally cannulated steers (550 kg) were fed a low-quality forage diet (43.1% ADF, 8.1% CP) in a 5 x 5 Latin square experiment. Mass and volume of ruminal contents were altered by adding varying numbers and weights of filled tennis balls (6.7-cm diameter) to the rumen immediately before the initiation of each experimental period. Treatments consisted of 0 balls (control), 50 balls with a 1.1 specific gravity (SG), 100 balls with a 1.1 SG, 50 balls with a 1.3 SG, and 100 balls with a SG of 1.3. The total volume of balls was 7.25 and 14.5 L for 50 and 100 balls, respectively. The total weight of balls was 8.5 and 17 kg for 50 and 100 balls with a 1.1 SG and 10.75 and 21.5 kg for 50 and 100 balls with a 1.3 SG, respectively. Daily DMI was 8.3, 7.3, 7.0, 6.5, and 6.0 kg for control; 50, 1.1 SG; 50, 1.3 SG; 100, 1.1 SG; and 100, 1.3 SG, respectively. Addition of balls to the rumen reduced (P < .01) DMI. Increasing the number (P < .01) and SG (P <. 01) of the balls decreased DMI further. However, digestibilities of DM, NDF, ADF, and CP were not influenced by treatment. Increasing the number of balls in the rumen increased (P < .05) rate of passage of digesta from the rumen, but increasing SG of the balls did not alter rate of passage. There was a treatment x hour interaction (P < .05) in the proportion of ruminal digesta with a functional specific gravity (FSG) less than 1.1, which decreased with time after feeding for the control but increased with time after feeding for other treatments. Ruminal passage rate of inert particles added in the rumen of different SG (1.1 and 1.3) and length (1 and 3 mm) decreased (P < .05) as SG of the balls increased. Mean fecal particle size was greater for those treatments with the heavier balls. Both the number and SG of balls (P < .10) influenced total VFA, and total concentrations were greater for the control and for the 1.1 SG than for the 1.3 SG treatments.