Dynamics of Haematobia irritans irritans (Diptera: Muscidae) infestation on Nelore cattle in the Pantanal, Brazil

From June 1993 to May 1995, horn fly counts were conducted twice a month on untreated Nelore cattle raised extensively in the Pantanal. Horn fly population showed a bimodal fluctuation and peaks were observed every year after the beginning (November/December) and at the end (May/June) of the rainy season, which coincided with mid-late spring and mid-late fall, respectively. Horn flies were present on cattle throughout the year in at least 64% of the animals. Mean horn fly numbers on animals did not exceed 85 flies/cow during peaks and were under 35 flies/cow in most of the remaining periods. The highest infestations (population peaks) were short and dropped suddenly within two weeks. Less than 15% of the animals in both herds could be considered as "fly-susceptible" - showing consistently higher infestations, or "fly-resistant" - showing consistently lower infestations.

Genetic polymorphisms related to meat traits in purebred and crossbred Nelore cattle

The objective of this work was to estimate the allelic and genotypic frequencies of CAST/XmnI, a calpastatin gene polymorphism, and CAPN530, a calpain 1 large subunit gene polymorphism, in different beef genetic groups (Nelore and Nelore x Bos taurus), and to investigate associations between these polymorphisms and carcass and meat traits. Three hundred animals - comprising 114 Nelore, 67 Angus x Nelore, 44 Rubia Gallega x Nelore, 41 Canchim, 19 Brangus three-way cross and 15 Braunvieh three-way cross- were genotyped by PCR-RFLP and phenotyped for rib-eye area (REA), back-fat thickness (BT), intramuscular fat (IF), shear force (SF) and myofibrillar fragmentation index (MFI). The occurrence of the two alleles of the CAST/XmnI and CAPN530 single nucleotide polymorphisms (SNPs) in a B. indicus breed, which permitted association studies in purebred and crossbred Nelore cattle, was first shown in the present work. No relationship was found between the CAST or CAPN1 SNPs and growth-related traits (REA) or fat deposition (BT and IF), since calpastatin and µ-calpain are not physiologically involved with these traits. Moreover, the association results between genotypes and aged meat tenderness (assessed by SF and MFI) showed that these markers are useless in assisted selection for purebred Nelore and their crosses with B. taurus.

SOFTWARE TO ASSESS BEEF CATTLE BODY MASS THROUGH THE FUZZY BODY MASS INDEX

ABSTRACT The Body Mass Index (BMI) can be used by farmers to help determine the time of evaluation of the body mass gain of the animal. However, the calculation of this index does not reveal immediately whether the animal is ready for slaughter or if it needs special care fattening. The aim of this study was to develop a software using the Fuzzy Logic to compare the bovine body mass among themselves and identify the groups for slaughter and those that requires more intensive feeding, using "mass" and "height" variables, and the output Fuzzy BMI. For the development of the software, it was used a fuzzy system with applications in a herd of 147 Nellore cows, located in a city of Santa Rita do Pardo city – Mato Grosso do Sul (MS) state, in Brazil, and a database generated by Matlab software.

Genetic improvement and population structure of the Nelore breed in Northern Brazil

The objective of this work was to evaluate the population structure and the genetic and phenotypic progress of Nelore cattle in Northern Brazil. Pedigree information concerning animals born between 1942 and 2006 were analyzed. Population structure was performed using the Endog program. Out of the 140,628 animals studied, 67.7, 14.52 and 3.18% had complete pedigree record of the first, second and third parental generation, respectively. Inbreeding and average relatedness coefficients were low: 0.2 and 0.13%, respectively. However, these parameters may have been underestimated, since information on pedigree was incomplete. The effective number of founders was 370 and the genetic contribution of 10, 50 and 448 most influent ancestors explained 13.2, 28 and 50% of the genetic variability in the population, respectively. The genetic variability for growth traits and population structure demonstrates high probability of increasing productivity through selective breeding. Moreover, management strategies to reduce the currently observed age at first calving and generation intervals are important for Nelore cattle genetic improvement.

Candidate SNPs for carcass and meat traits in Nelore animals and in their crosses with Bos taurus

The objective of this work was to evaluate the effects of single-nucleotide polymorphisms (SNPs) in the genes IGF1 (AF_017143.1:g.198C>T), MSTN (AF_320998.1:g.433C>A), MYOD1 (NC_007313:g.1274A>G) and MYF5 (NC_007303:g.1911A>G) on carcass and meat traits in Nelore (Bos indicus) and Nelore x B. taurus. A total of 300 animals were genotyped and phenotyped for rib eye area (REA), backfat thickness (BT), intramuscular fat (IF), shear force (SF) and myofibrillar fragmentation index (MFI). The effects of allele substitution for each SNP were estimated by regression of the evaluated phenotypes on the number of copies of a particular allele using the general linear model. The polymorphism at IGF1 was non-informative in Nelore animals. In crossbred animals, the IGF1 C allele was associated with greater REA. However, this relation was not significant after Bonferroni correction for multiple testing. The A allele of the MSTN polymorphism was absent in Nelore cattle and was only found in two crossbred animals. The polymorphisms of MYOD1 and MYF5 were little informative in Nelore animals with G allele frequency of 0.097 and A allele frequency of 0.031, respectively. These markers show no association with the analyzed traits in the total sample of evaluated animals.

Structure and composition of the ground-herb community in a terra-firme Central Amazonian forest

The herb community of tropical forests is very little known, with few studies addressing its structure quantitatively. Even with this scarce body of information, it is clear that the ground herbs are a rich group, comprising 14 to 40% of the species found in total species counts in tropical forests. The present study had the objective of increasing the knowledge about the structure and composition of the ground-herb community and to compare the sites for which there are similar studies. The study was conducted in a tropical non-inundated and evergreen forest 90 km north of Manaus, AM. Ground herbs were surveyed in 22 transects of 40 m², distributed in five plots of 4 ha. The inventoried community was composed of 35 species, distributed in 24 genera and 18 families. Angiosperms were represented by 8 families and Pteridophytes by 10 families. Marantaceae (12 sp) and Cyperaceae (4 sp) were the richest families. Marantaceae and Poaceae were the families with greatest abundance and cover. Marantaceae, Poaceae, Heliconiaceae and Pteridophytes summed 96% of total herb cover, and therefore were responsible for almost all the cover of the community. The 10 most important species had 83.7% of the individuals. In general, the most abundant species were also the most frequent. Richness per transect varied from 7 to 19 species, and abundance varied from 30 to 114 individuals. The community structure was quite similar to 3 other sites in South America and one site in Asia.

Extracellular serine-proteinases isolated from Streptomyces alboniger: Partial characterization and effect of aprotinin on cellular structure

Streptomyces alboniger ATCC 12461 grown in brain heart infusion (BHI) medium produced two extracellular serine-proteinases, denoted SP I and SP II, which were purified by ammonium sulfate precipitation and aprotinin-agarose affinity chromatography. SP I was purified 88,9-fold and SP II 66,7- fold, with 33.4% and 10.4% yield, respectively. The optimum pH for the proteinases activity, using a-N-p-tosyl-L-arginine-methyl ester (TAME) as substrate, was 9-10 and the optimum temperature was 37ºC. The proteolytic activity of SP I and SP II was inhibited by aprotinin and SP I was partially inhibited by leupeptin, both serine-proteinase inhibitors. S. alboniger growth in BHI-liquid medium decreased when 5 mg/ml, 10 mg/ml of aprotinin was used, being completely inhibited with 20 mg/ml and 40 mg/ml. At the ultrastructural level, aprotinin-treated S. alboniger cells showed swelling of the bacterial body and condensation of the genetic material, probably related to the inhibition of its growth.

Comparison between indirect enzyme-linked immunosorbent assays for Anaplasma marginale antibodies with recombinant major surface protein 5 and initial body antigens

Indirect enzyme-linked immunosorbent assays (ELISAs) based on recombinant major surface protein 5 (rMSP5) and initial body (IB) antigens from a Brazilian isolate of Anaplasma marginale were developed to detect antibodies against this rickettsia in cattle. Both tests showed the same sensitivity (98.2%) and specificities (100% for rMSP5 and 93.8% for IB ELISA) which did not differ statistically. No cross-reactions were detected with Babesia bigemina antibodies, but 5 (rMSP5 ELISA) to 15% (IB ELISA) of cross-reactions were detected with B. bovis antibodies. However, such difference was not statistically significant. Prevalences of seropositive crossbred beef cattle raised extensively in Miranda county, state of Mato Grosso do Sul, Brazil, were 78.1% by rMSP5 ELISA and 79.7% by IB ELISA. In the analysis of sera from dairy calves naturally-infected with A. marginale, the dynamics of antibody production was very similar between both tests, with maternal antibodies reaching the lowest levels at 15-30 days, followed by an increase in the mean optical densities in both ELISAs, suggesting the development of active immunity against A. marginale. Results showed that all calves were seropositive by one-year old, characterizing a situation of enzootic stability. The similar performances of the ELISAs suggest that both tests can be used in epidemiological surveys for detection of antibodies to A. marginale in cattle.

Fine structure of Henneguya hemiodopsis sp. n. (Myxozoa), a parasite of the gills of the Brazilian teleostean fish Hemiodopsis microlepes (Hemiodontidae)

A fish-infecting myxosporean, Henneguya hemiodopsis sp. n., found infecting the gills of Hemiodopsis microlepis and collected from the Poty River near the city of Teresina, Brazil, was described based on ultrastructural studies. The parasite occurred within large whitish polysporic plasmodia (up to 200 μm in diameter) containing asynchronous developmental sporogonic stages, mainly mature spores. The spores measured 19.7 ± 0.9 μm in total length (n = 30) and the ellipsoidal spore body was 10.8 ± 0.5 μm long, 3.3 ± 0.4 μm wide and 2.5 ± 0.5 μm thick. The spores were composed of two equal shell valves adhering together along the straight suture line, with each valve having equal-sized caudal tapering tails measuring 8.7 ± 0.6 μm in length. The spores were surrounded by a thin anastomosed network of microfibrils, more evident on the tails. There were two symmetric elongated bottle-like polar capsules 3.5 ± 0.3 μm long and 1.0 ± 0.2 μm wide, each with a polar filament with five to six coils. Given the morphological and ultrastructural differences from previously described parasites and the specificity of the host species, we propose a new species, named H. hemiodopsis sp. n.

A comparative study of fat body morphology in five mosquito species

The insect fat body plays major roles in the intermediary metabolism, in the storage and transport of haemolymph compounds and in the innate immunity. Here, the overall structure of the fat body of five species of mosquitoes (Aedes albopictus, Aedes fluviatilis, Culex quinquefasciatus, Anopheles aquasalis and Anopheles darlingi) was compared through light, scanning and transmission electron microscopy. Generally for mosquitoes, the fat body consists of lobes projecting into the haemocoel and is formed by great cell masses consisting of trophocytes and oenocytes. Trophocytes are rich in lipid droplets and protein granules. Interestingly, brown pigment granules, likely ommochromes, were found exclusively in the trophocytes located within the thorax and near the dorsal integument of Anopheles, which is suggestive of the role these cells play in detoxification via ommochrome storage. This study provides a detailed comparative analysis of the fat body in five different mosquito species and represents a significant contribution towards the understanding of the structural-functional relationships associated with this organ.

Genotyping Mycobacterium bovis from cattle in the Central Pampas of Argentina: temporal and regional trends

Mycobacterium bovis is the causative agent of bovine tuberculosis (TB), a disease that affects approximately 5% of Argentinean cattle. Among the molecular methods for genotyping, the most convenient are spoligotyping and variable number of tandem repeats (VNTR). A total of 378 samples from bovines with visible lesions consistent with TB were collected at slaughterhouses in three provinces, yielding 265 M. bovis spoligotyped isolates, which were distributed into 35 spoligotypes. In addition, 197 isolates were also typed by the VNTR method and 54 combined VNTR types were detected. There were 24 clusters and 27 orphan types. When both typing methods were combined, 98 spoligotypes and VNTR types were observed with 27 clusters and 71 orphan types. By performing a meta-analysis with previous spoligotyping results, we identified regional and temporal trends in the population structure of M. bovis. For SB0140, the most predominant spoligotype in Argentina, the prevalence percentage remained high during different periods, varying from 25.5-57.8% (1994-2011). By contrast, the second and third most prevalent spoligotypes exhibited important fluctuations. This study shows that there has been an expansion in ancestral lineages as demonstrated by spoligotyping. However, exact tandem repeat typing suggests dynamic changes in the clonal population of this microorganism.

Land-use systems affect Archaeal community structure and functional diversity in western Amazon soils

The study of the ecology of soil microbial communities at relevant spatial scales is primordial in the wide Amazon region due to the current land use changes. In this study, the diversity of the Archaea domain (community structure) and ammonia-oxidizing Archaea (richness and community composition) were investigated using molecular biology-based techniques in different land-use systems in western Amazonia, Brazil. Soil samples were collected in two periods with high precipitation (March 2008 and January 2009) from Inceptisols under primary tropical rainforest, secondary forest (5-20 year old), agricultural systems of indigenous people and cattle pasture. Denaturing gradient gel electrophoresis of polymerase chain reaction-amplified DNA (PCR-DGGE) using the 16S rRNA gene as a biomarker showed that archaeal community structures in crops and pasture soils are different from those in primary forest soil, which is more similar to the community structure in secondary forest soil. Sequence analysis of excised DGGE bands indicated the presence of crenarchaeal and euryarchaeal organisms. Based on clone library analysis of the gene coding the subunit of the enzyme ammonia monooxygenase (amoA) of Archaea (306 sequences), the Shannon-Wiener function and Simpson's index showed a greater ammonia-oxidizing archaeal diversity in primary forest soils (H' = 2.1486; D = 0.1366), followed by a lower diversity in soils under pasture (H' = 1.9629; D = 0.1715), crops (H' = 1.4613; D = 0.3309) and secondary forest (H' = 0.8633; D = 0.5405). All cloned inserts were similar to the Crenarchaeota amoA gene clones (identity > 95 %) previously found in soils and sediments and distributed primarily in three major phylogenetic clusters. The findings indicate that agricultural systems of indigenous people and cattle pasture affect the archaeal community structure and diversity of ammonia-oxidizing Archaea in western Amazon soils.

Genetic diversity and population structure of Brazilian native bovine breeds

Conservation and improvement strategies should be based on the association between genetic and phenotypic characteristics. The objective of this work was to characterize five native Brazilian cattle breeds (Caracu, Crioulo Lageano, Curraleiro, National Polled and Pantaneiro) and two commercial breeds (Holstein and Nellore) using RAPD technique to estimate genetic distances and variability between and within breeds. Genetic relationships were investigated using 22 primers which generated 122 polymorphic bands. Analysis of molecular variance indicated that most of the genetic variation lay among individuals within populations. The genetic variabilities between pairs of breeds were statistically significant. The smallest genetic divergence was between Crioulo Lageano and Curraleiro.The National Polled, although historically considered to be of Bos taurus aquitanicus origin,similar to theCaracu, was grouped together with the other breeds of Bos taurus ibericus origin. Generally, the individual breeds formed distinct clusters except the National Polled. The RAPD technique was capable to distinguish genetically between the breeds studied; the Caracu, Crioulo Lageano, Curraleiro and Pantaneiro may be considered distinct genetic entities thereby proving the uniqueness of the populations; the National Polled has not been able to re-establish itself after its decline in the 1950s, thereby losing its genetic identity.

Histological changes caused by experimental Riedeliella graciliflora (Leg. Papilionoideae) poisoning in cattle and laboratory animals

Tissues from cattle, mice, rats and guinea pigs experimentally intoxicated by Riedeliella graciliflora were studied histologically. Cattle lymph nodes, spleen, Peyer patches and peribronchial lymphoid tissues had diffuse necrosis of lymphocytes, mainly in the germinal centers of the follicles. This lesion was less severe in laboratory animals. All species had severe enteritis with infiltration of the lamina propria by mononuclear cells. Some cells in this infiltrate were necrotic. Degeneration and necrosis of the epithelial cells, mainly in the tip of the villi, and detachment of the epithelial lining from the lamina propria were also observed. In the liver the trabecular structure was disrupted and the hepatocytes had some degree of individual necrosis and degeneration. A tubular nephrosis was observed in the kidneys. Liver, lung, kidney, intestine and lymph nodes had different degrees of congestion. Those lesions are similar than those caused by Polygala klotzschii, a plant that contains 5-metoxi-podophyllotoxin.

Impact of ivermectin-resistant gastrointestinal nematodes in feedlot cattle in Argentina

The aim was to evaluate for 75 days the impact on production of the remaining burden of ivermectin (IVM)-resistant parasites in naturally infected feedlot calves. The herds came from tick-infested areas of cattle breeding where the systematic use of IVM to control tick increases the gastrointestinal parasites resistant to this drug. This investigation was carried out in two commercial feedlots in Buenos Aires province. In feedlot A, two groups of 35 animal each received IVM 1% and the other received ricobendazole (RBZ) 10% respectively. The same was done in feedlot B. On day 0, two groups of 35 animals were made in feedlots A and B. Fecal samples were taken on days 0, 22, 54 and 75 pos-treatment (PT), and body weight was registered, from each animal. Fecal samples were processed for individual count of eggs per gram (EPG) and pooled fecal culture was carried out for identification of the parasite genus in each sampling. Fecal egg count reduction test (FECR) was calculated on day 22 PT. The study design used was a totally randomized block, with commercial feedlot and sex as block variables. For data analysis, a mixed model of the SAS statistical program was used. The FECR average on day 22 was 28.4% in the IVM group, and 94,2 % in the RBZ group . From this date on, significant differences in EPG were kept until day 54. EPG counts were only equal near the end of the trial, on day 75 (p=0.16). In both commercial feedlots, especially in the IVM group, Cooperia spp. was the most prevalent parasite in the fecal cultures. Significant differences in weight (P<0.01) on post-treatment day 75 was found between the average weight in the RBZ and the IVM group (246 vs. 238 kg respectively), what means a difference of 8.3% in gains. The importance for production in the antiparasite failure treatment in commercial feedlots was demonstrated, and the need of pos-treatment controls to evaluate the efficacy of the antiparasitic administered is emphasized.