Autoregressive and random regression test-day models for multiple lactations in genetic evaluation of Brazilian Holstein cattle

Autoregressive (AR) and random regression (RR) models were fitted to test-day records from the first three lactations of Brazilian Holstein cattle with the objective of comparing their efficiency for national genetic evaluations. The data comprised 4,142,740 records of milk yield (MY) and somatic cell score (SCS) from 274,335 cows belonging to 2,322 herds. Although heritabilities were similar between models and traits, additive genetic variance estimates using AR were 7.0 (MY) and 22.2% (SCS) higher than those obtained from RR model. On the other hand, residual variances were lower in both traits when estimated through AR model. The rank correlation between EBV obtained from AR and RR models was 0.96 and 0.94 (MY) and 0.97 and 0.95 (SCS), respectively, for bulls (with 10 or more daughters) and cows. Estimated annual genetic gains for bulls (cows) obtained using AR were 46.11 (49.50) kg for MY and −0.019 (−0.025) score for SCS; whereas using RR these values were 47.70 (55.56) kg and −0.022 (−0.028) score. Akaike information criterion was lower for AR in both traits. Although AR model is more parsimonious, RR model assumes genetic correlations different from the unity within and across lactations. Thus, when these correlations are relatively high, these models tend to yield to similar predictions; otherwise, they will differ more and RR model would be theoretically sounder.     

Anthelmintic activity of Jatropha curcas L. seeds on Haemonchus contortus

The aim of this study was to evaluate the anthelmintic activity of hexane (HE), ethyl acetate (EA) and ethanol (EE) extracts obtained from the seeds of Jatropha curcas using the egg hatch inhibition assay (EHA) and the artificial larval exsheathment inhibition assay (LEIA). For the egg hatch assay, HE, EA and EE were used in concentrations of 3.12, 6.25, 12.5, 25 and 50 mg ml(-1), accompanied by a negative control (5% Tween 80) and a positive control (0.025 g ml(-1) thiabendazole). In LEIA, the extracts were tested at a concentration of 1000 μg ml(-1), accompanied by a negative control (PBS). To evaluate the effect of tannins, the extract with the greatest effect was incubated with polyvinyl polypyrrolidone (PVPP). The EE (50 mg ml(-1)) inhibited 99.8% of egg hatching. After the addition of PVPP, the ovicidal effectiveness of EE was reduced to 91.9%. Using the HE and EA, inhibition of egg hatching was 15.3% and 32.2%, respectively. In the LEIA, 18.9% of L3 incubated with EE were exsheathed (p<0.01). The addition of PVPP to EE reversed the inhibitory effect on larval exsheathment. The percentage of exsheathment of L3 incubated with HE (99.6%) and EA (97.8%) did not differ from the control group (p>0.05). The results show that the effects of EE on eggs are not solely due to the tannins. However, these secondary metabolites are implicated in blocking the larval exsheathment.     

Changing climate and changing vector-borne disease distribution: the example of Dirofilaria in Europe

Climatic changes, together with an increase in the movement of dogs across Europe, have caused an increase in the geographical range of Dirofilaria infections. The present paper is focuses on northeastern European countries, where survey data have shown an increase of Dirofilaria repens infections both in animals and humans. A growing degree day-based forecast model has been developed to predict the occurrence. The model is based on evidence that there is a threshold of 14 °C below which Dirofilaria development will not proceed in mosquitoes, there is a requirement of 130 growing degree-days (GDDs) for larvae to reach infectivity, and there is a maximum life expectancy of 30 days for a mosquito vector. The output of this model predicted that the summer temperatures (with peaks in August) are sufficient to facilitate extrinsic incubation of Dirofilaria even at latitudes of 56 °N and longitudes of 39 °E. Despite the fact that both Dirofilaria immitis and D. repens have the same temperature requirement for extrinsic incubation in mosquitoes, empirical data has shown that D. repens is the main cause of dirofilarial infections in both humans and animals. Clinical signs are absent in most canine infections with D. repens. Furthermore, diagnosis is problematic and in-clinic serological tests, such as those for D. immitis, do not exist. Therefore, most infections go undiagnosed, allowing the infection to spread undetected.     

Activities of adenine nucleotide and nucleoside degradation enzymes in platelets of rats infected by Trypanosoma evansi

Pigeons (Columba livia) cohabit with humans in urban and rural areas, representing a public health problem since microorganisms are transmitted through the inhalation of dust from their dry feces (chlamydiosis) and through ingestion of their undercooked or poorly refrigerated meat (toxoplasmosis). This study aimed to evaluate the presence of Chlamydophila psittaci and Toxoplasma gondii in pigeons from four cities in São Paulo State, Brazil. C. psittaci was evaluated through hemi-nested polymerase chain reaction (hnPCR) using cloacal and tracheal swabs, whereas T. gondii specific antibodies were assessed by means of modified agglutination test (MAT), mouse brain and muscle bioassay, and polymerase chain reaction (PCR). To confirm the infection in mice, T. gondii antibodies were assayed by using indirect fluorescent antibody test (IFAT). Considering C. psittaci, 40/238 (16.8%; 95%CI 12.6–22.1%) samples were positive according to hnPCR, especially for the cities of São Paulo (42.5%) and Bauru (35%). As regards T. gondii, 12/238 (5%; 95%CI 2.9–8.6%) serum samples were positive according to MAT. Of these, five samples had titer equal to 1:8; six samples, 1:16; and one sample, 1:32. Bioassay, IFAT and PCR were negative for mouse toxoplasmosis. The absence of T. gondii antibodies suggests that pigeons may be infected with a low concentration of the agent, not detected by the antigen test. Thus, C. psittaci represents an actual problem concerning bird health.     

Pathological changes caused by Anoplocephala perfoliata in the mucosa/submucosa and in the enteric nervous system of equine ileocecal junction

In this study, pathological changes caused by Anoplocephala perfoliata in the ileocecal junction were investigated in 31 regularly slaughtered mixed-breed horses of both sexes. Our results showed a significant relationship between parasite burden and grading of histopathological lesions in the mucosa and submucosa. Hypertrophy of the circular muscle layer was found in infected horses. Moreover, enteric nervous system evaluation showed a significant injury of intestinal nervous elements in the horses with moderate to high parasitism expressed as an increase of degenerative-regressive changes in neuronal cells and a decrease in the number of myenteric ganglia and neuronal cells. These findings can help to clarify the pathogenesis of intestinal motility disorders associated with A. perfoliata infection in horses.     

National control and eradication program of bovine tuberculosis in Chile

There have been reports of the presence of bovine tuberculosis (TB) in Chile for more than 100 years. Several prevalence studies have revealed that there is a wide spectrum of disease across the country with certain geographic areas where the disease is endemic through to other geographic areas where infection is sporadic and at very low prevalence. In 2009, this information was used to divide Chile into different geographic zones based on prevalence rates. This will enable the correct actions to be undertaken to reduce the prevalence of TB. Thus the northern part of Chile which has a medium to high prevalence of TB will be categorized as a control zone. In contrast, the southern part of Chile which has a high proportion of the bovine population, has a low prevalence of TB and will be classified as an eradication zone (Paredes, 2008). Although there have been several past attempts to create a national control and eradication program in Chile, none has been successful. A national program is proposed, and outlined in this paper. Progress toward program initiation in 2009 has been difficult, mostly because of the global economic crisis, difficulties in the milk and meat industry, and social and political issues.     

Impact of glutathione on the formation of methylmethine- and carboxymethine-bridged (+)-catechin dimers in a model wine system

This study was performed to assess the impact of glutathione on the reaction between (+)-catechin and carbonyl compounds in wine-related conditions. (+)-Catechin (0.50 mM) and either glyoxylic acid (0.25 mM) or acetaldehyde (0.25 mM) were added to a model wine system with 0.0, 0.25, and 2.5 mM of glutathione added. UPLC-DAD and LC-MS analysis showed that the formation of carbonyl-bridged (+)-catechin dimers was inhibited in the samples with a glutathione to carbonyl ratio of 10:1 compared to the samples without glutathione. At a ratio of 1:1, glutathione inhibited the acetaldehyde-bridged dimers but only had a minor impact on the glyoxylic acid-bridged dimers. Further investigations showed that this trend of inhibition by glutathione on the glyoxylic acid-derived dimer was independent of temperatures, 20 °C vs 45 °C, or the presence of metal ions, 0.2 mg/L copper(II) and 5 mg/L iron(II). (1)H NMR analysis and LC-MS analysis provided evidence that glutathione inhibited dimer formation via different mechanisms depending on the carbonyl compound. For acetaldehyde-derived dimers, the main mode of inhibition was the ability of glutathione to form a (methyl-glutathionyl-methine)-(+)-catechin complex. Alternatively, the formation of a glutathione-glyoxylic acid addition product impeded the reaction between glyoxylic acid with (+)-catechin. These results demonstrate that glutathione, at sufficient concentration, can have a substantial impact on carbonyl-derived polymerization reactions in wine-like conditions.