Continuous milking of dairy cows disrupts timing of peak IgG concentration appearance in mammary secretions

The length of the dry period in commercial dairy production is under close scrutiny. While the main concern is the composition and volume of milk produced, the evaluation of colostrum quality under these new paradigms has suggested a decline in IgG concentrations, while some reports indicate no change. Colostrum quality has been defined as an adequate concentration (>50 mg/ml) of immunoglobulin in the secretions to provide the newborn with maximal disease resistance. We investigated the appearance of IgG in mammary pre- and post partum secretions in cows without a dry period (continuously milked, Dry0) and compared the secretions with cows that experienced a dry period of 60 d (Dry60). Blood was collected during the experimental period and plasma analysed for progesterone (P4) and prolactin (Prl). Approximately -6 d relative to parturition, the Dry0 animals exhibited increased concentration of IgG in their secretions to an average of ∼35 mg/ml that remained rather constant through subsequent pregnancy and following parturition. Dry0 cows were producing an average IgG concentration in parturition colostrum of 44·2±17·6 mg/ml that was not different than that of controls (66·86±16·8 mg/ml). However, Dry0 cows exhibited high variation, different peak times (day) of IgG concentration including times that occurred both pre and post parturition. IgG mass of the Dry0 cows remained rather constant pre- and post partum and did not show the same declining mass following parturition that was shown for the Dry60 cows. The change in plasma P4 and Prl were shown to have no timing effect on colostrum IgG concentration.

Use of outdoor ranges by laying hens in different sized flocks.

In studies assessing outdoor range use of laying hens, the number of hens seen on outdoor ranges is inversely correlated to flock size. The aim of this study was to assess individual ranging behavior on a covered (veranda) and an uncovered outdoor run (free-range) in laying hen flocks varying in size. Five to ten percent of hens (aged 9–15 months) within 4 small (2–2500 hens), 4 medium (5–6000), and 4 large (≥9000) commercial flocks were fitted with radio frequency identification (RFID) tags. Antennas were placed at both sides of all popholes between the house and the veranda and the veranda and the free-range. Ranging behavior was directly monitored for approximately three weeks in combination with hourly photographs of the free-range for the distribution of hens and 6h long video recordings on two parts of the free-range during two days. Between 79 and 99% of the tagged hens were registered on the veranda at least once and between 47 and 90% were registered on the free-range at least once. There was no association between the percentage of hens registered outside the house (veranda or free-range) and flock size. However, individual hens in small and medium sized flocks visited the areas outside the house more frequently and spent more time there than hens from large flocks. Foraging behavior on the free-range was shown more frequently and for a longer duration by hens from small and medium sized flocks than by hens from large flocks. This difference in ranging behavior could account for the negative relationship between flock size and the number of hens seen outside at one point of time. In conclusion, our work describes individual birds’ use of areas outside the house within large scale commercial egg production.

Production and characterization of a custom-made 228Th source with reduced neutron source strength for the Borexino experiment

A custom-made 228Th source of several MBq activity was produced for the Borexino experiment for studying the external background of the detector. The aim was to reduce the unwanted neutron emission produced via (alpha,n) reactions in ceramics used typically for commercial 228Th sources. For this purpose a ThCl4 solution was converted chemically into ThO2 and embedded into a gold foil. The paper describes the production and the characterization of the custom-made source by means of gamma-activity, dose rate and neutron source strength measurements. From gamma-spectroscopic measurements it was deduced that the activity transfer from the initial solution to the final source was >91% (at 68% C.L.) and the final activity was (5.41+-0.30) MBq. The dose rate was measured by two dosimeters yielding 12.1 mSv/h and 14.3 mSv/h in 1 cm distance. The neutron source strength of the 5.41 MBq 228Th source was determined as (6.59+-0.85)/sec.

Evaluation of a new commercial enzyme-linked immunosorbent assay for the detection of porcine antibodies against Trichinella spp

Trichinellosis is a zoonotic disease that is caused by the nematode Trichinella spp. Both European Union regulations and guidelines from the World Organization for Animal Health foresee the possibility of conducting serological surveillance for Trichinella spp. A newly developed commercial enzyme-linked immunosorbent assay (ELISA) was evaluated against 2 existing diagnostic techniques: an in-house ELISA and an in-house Western blot. A total of 875 Trichinella larva-negative samples of pigs and 93 Trichinella larva-positive samples of both naturally and experimentally infected pigs were included in the study. Bayesian modeling techniques were used to correct for the absence of a perfect reference test. The sensitivity and specificity of the commercial ELISA was 97.1-97.8% and 99.5-99.8%, respectively. Sensitivity analysis demonstrated high stability in the models. In a serological surveillance system, ELISA-positive samples should be tested by a confirmatory test. The Western blot is a suitable test for this purpose. With the use of the results of the models, the sensitivity and specificity of a test protocol in both ELISA and Western blot were 95.9% and 99.9%, respectively. The high sensitivity and specificity were achieved with a lower limit of detection than that of the routine artificial digestion test, suggesting that serological surveillance is a valuable alternative in surveillance for Trichinella spp. in pig production.

Production of antibodies to canine IL-1beta and canine TNF to assess the role of proinflammatory cytokines

IL-1 and TNF are important proinflammatory cytokines implicated in both antimicrobial host defense and pathogenesis of diseases with an immune-mediated and/or inflammatory component. Respective studies in the dog have been hampered by the unavailability of reagents allowing the specific measurement of canine cytokine proteins and the effect of canine cytokine neutralization by Ab. Starting with recombinant canine (rcan) IL-1beta and rcanTNF, four polyclonal antisera and 22 mAb specific for rcanIL-1beta and rcanTNF were generated. Their usefulness in neutralization assays was determined. Using cytokine-containing supernatants of canine cells in bioassays, polyclonal antisera neutralized either canine IL-1beta or TNF. TNF was also neutralized by three antibodies developed in this study and one commercial mAb. The usefulness of monoclonal and polyclonal Ab in canine cytokine-specific Ab capture ELISA's was assessed. This resulted in the identification of a commercial mAb combination and one pair developed in this study allowing low levels of TNF to be detected by antibody capture ELISA. The detection limit was 141 pg/ml rcanTNF for both combinations. Using rcanIL-1beta as an antigen allowed the detection of lower concentrations of rcanIL-1beta (20 pg/ml, on the average) by a pair of polyclonal antisera than when monoclonals were used. By using such IL-1beta-specific and TNF-specific ELISA's, the respective cytokines were detected in supernatants of canine PBMC stimulated with LPS or heat-killed Listeria monocytogenes and interferon-gamma combined. Thus, monoclonal and polyclonal reagents were identified allowing the quantitation of canine IL-1beta and TNF production in vitro, and the neutralization of these cytokines.