Caprine toxoplasmosis in Southern Brazil: a comparative seroepidemiological study between the indirect immunofluorescence assay,the enzyme-linked immunosorbent assay,and the modified agglutination test

Tropical Animal Health and Production - This study investigated the prevalence of caprine toxoplasmosis in goat herds from Southern Brazil by the indirect immunofluorescence assay (IFA), and...     

Effects of huanglongbing on fruit quality of sweet orange cultivars in Brazil

Citrus huanglongbing (HLB), associated with Candidatus Liberibacter asiaticus and Ca. L. americanus and transmitted by the Asian psyllid Diaphorina citri, is the most serious disease of citrus worldwide because of crop devastation and difficulty to control. Since 2004, approximately 3 million trees were eliminated in attempts to limit its spread in Brazil. Where HLB becomes endemic, the disease progression in the orchard and the increasing symptom severity throughout the tree canopy can be relatively fast, greatly reducing the economic life of affected orchards because of tree decline and yield reduction. Although the majority of the fruit from symptomatic branches drop before harvest, a significant amount of affected fruit remain attached, are available for harvest, and can affect juice quality. To quantify and compare the effects of HLB on fruit quality of the most important sweet orange cultivars grown in São Paulo State, 4–6 year-old sweet orange trees from 26 blocks (two of ‘Valencia Americana’, eight of ‘Hamlin’, four of ‘Westin’, seven of ‘Pera’, and five of ‘Valencia’) were selected prior to harvest. In each block, 14–21 HLB-symptomatic trees were chosen. In each tree, the quality of 20 fruit normal in appearance from asymptomatic branches and 20 symptomatic fruit from symptomatic branches were assessed. In general, compared to normal fruit, the symptomatic fruit were small, light, more acidic, and had lower juice percentage, Brix, total soluble solids per box, total soluble solids per fruit, and Brix/acidity ratio. These effects of fruit quality were less pronounced on early and mid season sweet orange cultivars than on late season cv. Valencia.     

Association between quantitative bacterial culture of bronchoalveolar lavage fluid and antibiotic requirement in dogs with lower respiratory tract signs

BackgroundHistorically, positive bacterial cultures from the lower respiratory tract (LRT) have been considered clinically relevant when quantitative bacterial cultures of bronchoalveolar lavage fluid (BALF) were >1700 colony forming units (cfu)/mL. However, this threshold might not accurately predict a requirement for antibiotics.ObjectivesTo study whether quantitative BALF bacterial culture results were predictive of antibiotic requirement in dogs with LRT signs.AnimalsThirty‐three client‐owned dogs.MethodsCross‐sectional study. Dogs with positive quantitative bacterial culture of BALF were included. Dogs were divided into 2 groups, depending on whether they had a LRT infection requiring antibiotics (LRTI‐RA) or LRT disease not requiring antibiotics (LRTD‐NRA), based on thoracic imaging features, presence of intracellular bacteria on BALF cytology, and response to treatment. Predictive effect of cfu/mL and BALF total nucleated cell count (TNCC) on antibiotic requirement, adjusting for ongoing or prior antibiotic therapy and age, were studied using logistic regression.ResultsTwenty‐two and 11 dogs were included in the LRTI‐RA and LRTD‐NRA groups, respectively. The cfu/mL was not significantly predictive of antibiotic requirement, independent of ongoing or prior antibiotic treatment and age (LRTI‐RA: median, 10 000 cfu/mL; range, 10‐3 × 10⁸; LRTD‐NRA: median, 10  000 cfu/mL; range, 250‐1.3 × 10⁹; P = .27). The TNCC was not significantly predictive of antibiotic requirement when only dogs with bronchial disease were considered (LRTI‐RA: median, 470 cells/μL; range, 240‐2260; LRTD‐NRA: median, 455 cells/μL; range, 80‐4990; P = .57).Conclusion and Clinical ImportanceThe cfu/mL is an inappropriate measure for determining whether antibiotics are of benefit in dogs with LRT signs.     

Nitrogen Uptake and Its Association with Grain Yield in Lowland Rice Genotypes

ABSTRACT

Nitrogen is one of the most yield–limiting nutrients in lowland rice in Brazil. A field experiment was conducted for two consecutive years to evaluate nitrogen (N) uptake by five lowland rice genotypes and its association with grain yield. The nitrogen rate used was 0, 50, 100, 150, and 200 kg ha^?1. The genotypes evaluated were CNAi 8886, CNAi 8569, BRSGO Guará, BRS Jaburu, and BRS Biguá. Grain yield and dry matter yield of shoot were significantly influenced by N rate. However, response varied from genotypes to genotypes. Genotype BRSGO Guará, BRS Bigua, and BRS Jaburu were having linear response, whereas genotypes CNAi 8886 and CNAi 8569 were having quadratic response with the N application rate in the range of 0 to 200 kg ha^?1. Overall, genotypes BRSGO Guará and CNAi 8886 were the best because they produced higher yield at low as well as at higher N rates. Nitrogen uptake in shoot was having quadratic relationship with grain yield, whereas nitrogen uptake in the grain was linearly associated with grain yield.     

Reproductive seasonality in Saanen goats kept under tropical conditions

Tropical Animal Health and Production - This study aimed to verify the reproductive seasonality in Saanen goats from distinct parity orders (nulliparous, primiparous, and pluriparous) throughout an...     

Studying the function of ecosystem in preventing aeolian dust emission in the dryland areas of China

Aeolian dust emissions can cause many environmental hazards, like accelerating land degradation and desertification, polluting air, harming human health, and so on. The dryland areas of China (DAC) are hot spots of aeolian dust emissions. To date, many efforts have been paid to researching dust emissions processes and effects, but research studies on ecosystems' function in preventing dust emissions are still very limited. In this study, we investigated the function of DAC ecosystems in preventing dust emissions, and the corresponding driving factors through integrated wind erosion modelling system (IWEMS) modelling. The main results indicate that: (1) from 2001 to 2020, the ecosystems of DAC prevented the emission of dust ~40,554 Tg, approximately 15 times as much as the total actual dust emission (~2776 Tg); (2) the function of DAC ecosystems in preventing dust emissions was relatively strong in spring and winter; (3) grassland ecosystems had the strongest function in preventing dust emissions among all the land cover types, avoiding the emission of dust ~20,857 Tg over 2001–2020; (4) dust emission prevention function provided by the DAC ecosystems benefits almost every region of China, which provides a theoretical basis for formulating ecological compensation policies; and (5) the changes in dust emissions were dominated by wind speed in most areas of DAC.     

Shading effects on canopy and tillering characteristics of continuously stocked palisadegrass in a silvopastoral system in the Amazon biome

In silvopastoral (SP) systems, forage responses depend on the microenvironment in which the plants develop. Our objective was to evaluate canopy and tillering characteristics of shaded 'Marandu' palisadegrass [Brachiaria brizantha (Hochst A Rich) Stapf, syn. Urochloa brizantha] under continuous stocking in a SP system. Treatments were one full sun (FS) and three shaded systems (silvopasture, SP) corresponding to distances from tree groves: 7.5 m north (SP1), and 15 m (SP2) and 7.5 m south (SP3) studied during two rainy seasons (Year 1 and Year 2). The tree in the SP system was Eucalyptus urograndis (hybrid of Eucalyptus grandis W. Hill ex Maiden × Eucalyptus urophylla S. T. Blake). The photosynthetic active radiation was greater in FS (923 μmol m^-2 s^-1), followed by SP2 (811 μmol m^-2 s^-1), SP1 (727 μmol m^-2 s^-1) and SP3 (673 μmol m^-2 s^-1). Forage accumulation in FS was 15% greater than the mean of SP1, SP2 and SP3 (10,663 kg DM/ha). There was no difference in net accumulation of leaf, stem and dead material, averaging 3,302, 3,420 and 4,063 kg DM/ha respectively. Leaf accumulation and accumulation rate were greater in Year 2, and leaf accumulation rate was similar among treatments (19 kg DM ha⁻¹ day⁻¹). Leaf proportion increased 14% from Year 1 to Year 2. Specific leaf area was greater for treatments SP1 and SP3 (193 cm²/g). Tiller population density was similar across treatments in Year 1. Shaded palisadegrass maintains leaf productivity similar to FS under continuous stocking in an SP system.     

Nitric oxide impacts bovine sperm capacitation in a cGMP‐dependent and cGMP‐independent manner

We aimed to elucidate whether NO acts in in vitro sperm capacitation in bovine via cGMP/PKG1 pathway. For this, cryopreserved bovine sperm were capacitated in vitro with 20 µg/ml heparin (Control) plus treatments: 1 mM L‐arginine (L‐arg, NO precursor), 50 µM Rp‐8‐Bromo‐β‐phenyl‐1,N²‐ethenoguanosine‐3′,5′‐cyclic monophosphorothioate (Rp‐8‐Br‐cGMPS, selective inhibitor of the binding site for cGMP in PKG1), 1 mM 2‐Phenyl‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl 3‐oxide (PTIO, NO scavenger), and the combinations of L‐arg + RP‐8‐Br‐cGMPS and L‐arg + PTIO. Sperm motility and vigour were determined by phase‐contrast microscopy, capacitation status by chlortetracycline staining, and the intracellular concentration of cGMP was measured by ELISA. Data were subjected to analysis of variance and means compared with SNK test at 5% probability. Motility and vigour were lower in sperm treated with PTIO when compared to Control and other treatments (p < .05). The L‐arg treatment showed the highest percentage of capacitated sperm when compared to the Control and other treatments (Rp‐8‐Br‐cGMPS, L‐arg + Rp‐8‐Br‐cGMPS and PTIO) (69.8 ± 3.4%, 51.2 ± 3.0, 51.1 ± 2.1, 51.2 ± 3.0 and 45.5 ± 2.7, respectively) (p < .05). The capacitation ratio (%) was lower in treatments with Rp‐8‐Br‐cGMPS, L‐arg + Rp‐8‐Br‐cGMPS and PTIO, respectively (p < .05). Lastly, cGMP concentration (pmol/ml) was lower in PTIO and L‐arg + PTIO (1.3 ± 0.3 and 1.6 ± 0.4) and was higher in Rp‐8‐Br‐cGMPS and L‐arg + Rp‐8‐Br‐cGMPS (3.7 ± 0.4 and 4.0 ± 0.5) treatments. We showed that during in vitro capacitation of cattle: (a) NO influences sperm motility and vigour; (b) NO is associated with cGMP synthesis through two independent pathways and (c) the cGMP/PKG1 pathway has a partial role in sperm capacitation and does not involve the L‐arg/NO.