Taurus Cattle Research Articles

Absence of a corpus luteum and relatively lesser concentrations of progesterone during the period of pre-ovulatory follicle emergence results in lesser pregnancy rates in Bos indicus cattle

Concentrations of progesterone before AI have had variable effects on fertility in both Bos indicus and Bos taurus cattle. The aim of this study was to determine if fertility and concentrations of progesterone after AI were affected in Bos indicus females when pre-ovulatory follicles develop in the absence or presence of a corpus luteum (CL). Between 6.5–7.5 days after a synchronised oestrus, all follicles ≥4 mm in diameter were aspirated (Day 0) and cloprostenol was administered on Days 0 and 1 (LP4, n = 36) or on Days 4 and 5 (HP4, n = 40). Animals were inseminated on detection of oestrus until Day 9. Breeding continued using natural mating between Days 9 and 19, AI on detection of oestrus between Day 19 and 29 and natural mating between Days 29–90. Mean concentrations of progesterone were less on Days 2–4 in the LP4 compared to the HP4-treated animals but similar on Days 14 and 20. In the LP4- compared to the HP4-treated animals, the odds of being detected in oestrus and ovulating close to the first AI were similar, but odds of pregnancy to first AI (OR = 0.19, 95% CI 0.07 – 0.52) and after 1, 4 and 13 weeks of breeding were less (P ≤ 0.051). Absence of a CL and relatively lesser concentrations of progesterone during emergence of pre-ovulatory follicles resulted in lesser pregnancy rates to AI in Bos indicus cattle but did not affect concentrations of P4 after ovulation.

Heat tolerance responses in a Bos taurus cattle herd raised in a Brazilian climate

Knowledge of thermoregulatory responses in taurine cattle contribute to identification of animals most adapted to heat and productive when raised under Brazilian climate. The objectives were to verify the morphological and physiological responses related to adaptation to heat of taurine breeds raised under in Brazilian meteorological conditions in different seasons of the year and day periods, and to detect differences within and between breeds to know breed is most adapted. Measurements were made of 74 young bulls (n = 31 Angus; n = 43 Simmental) for the morphological traits: hair length (HL), number of hairs (NH), and coat thickness (CT); and for the physiological traits: respiratory rate (RR) and hair coat surface temperature (ST). The temperature-humidity index (THI) was calculated. The data were subjected to analyses of variance, cluster analysis, and principal component analysis (PCA). The THI (<74) indicates thermal comfort. In the winter, the HL and CT higher than in the spring season (P < 0.0001) in both breeds. Angus exhibited higher HL and CT (P < 0.0001). Within each breed, the animals differed from one another for HL (P < 0.0005). In the spring, CT was similar between the breeds, differing only in the winter season. Angus had higher values (P < 0.0005) of RR and lower values (P < 0.0001) of ST. Both breeds had higher (P < 0.0001) RR and ST in the afternoon. PCA showed that NH and HL better explained variation in adaptation. In general, the breeds have similar morphological responses in the hottest months, but have different physiological responses; Simmental proves to be more physiologically resistant. The afternoon was more stressful than the morning, even though the animals were in a thermal comfort zone. Measuring traits related to hair coat is sufficient for effective evaluation of adaptation, and the season affects the morphological and physiological traits of taurine cattle raised.

Impact of fetal vs. maternal contributions of Bos indicus and Bos taurus genetics on embryonic and fetal development1

To evaluate how the inclusion of Bos indicus genotype influences early fetal development in cattle, a reciprocal embryo transfer approach was used in a completely randomized design with a 2 × 2 × 2 factorial arrangement of treatments to generate 55 pregnancies over 2 consecutive years (n = 55). Recipient cows were randomly assigned to (i) a diet that met daily energy maintenance requirements (MAINT) or (ii) a diet that restricted intake to 70% of the energy maintenance requirements (RESTR). Angus (AN) and Brangus (BN) embryo donors were superovulated and artificially inseminated with female sexed-sorted semen from the same breed. Embryos were then randomly transferred to either AN or BN recipients fed their respective diets for 28 d. Recipients remained on the dietary scheme until day 91 of gestation and were then comingled and fed a common diet that met their energy requirements until calving. Measurements included pregnancy establishment at day 28 of gestation, interferon-stimulated genes (ISG) expression in peripheral blood leukocytes, pregnancy-associated glycoproteins (PAG; using two commercial [A1 and A2] and one in-house assay), and fetal crown-to-rump length (CRL). Recipients in the RESTR diet had lower BWs and BCS (diet × day; P < 0.01) than MAINT recipients. Energy-restricted AN recipients experienced greater (recipient breed × diet, P < 0.01) pregnancy failure by day 28 than the other recipient breed × diet combinations. Restricted recipients that received AN embryos experienced greater pregnancy failure than RESTR recipients receiving BN embryos (embryo breed × diet; P = 0.03). No relevant differences were observed in ISG expression (P > 0.10). Recipients that received BN embryos had greater plasma concentrations of PAG in both A1 (embryo breed × day, P < 0.01) and A2 (embryo breed; P < 0.01). Alternatively, recipients that received AN embryos had greater plasma concentrations of PAG for the in-house assay (embryo breed × day; P < 0.01). In addition, fetuses from AN recipients had greater CRL on day 91 (breed × day, P < 0.01). In summary, Bos taurus cows experienced greater pregnancy failure when nutrient restricted. Furthermore, fetal size and the profile of PAG production during early gestation differed between B. indicus-influenced and B. taurus cattle.

Tick burden in Bos taurus cattle and its relationship with heat stress in three agroecological zones in the tropics of Colombia

BackgroundTicks have a negative effect on dairy and beef cattle production systems around the world, with the concomitant risk they represent for the transmission of some important infectious diseases. Colombian cattle breeds are distributed across different agroecological regions and are exposed to different environmental challenges. In humid and warmer climates such as those from the tropics, tick burden and heat stress are important factors that can compromise livestock performance. The aim of this study was to characterize tick burden in four Colombian cattle breeds and evaluate the relationship between heat stress and tick burden in Bos taurus cattle under tropical conditions. Tick counting was conducted in 1332 cattle from Romosinuano (ROMO), Costeño con Cuernos (CCC), San Martinero (SM) and Blanco Orejinegro (BON) breeds, located in the Caribbean, Orinoquia and Andean regions. Vital signs and environmental variables were taken to calculate an adaptability index (AI) and a temperature humidity index (THI). An AI < 2 indicates maximum adaptability while an AI ≥ 2 indicates a state of lower adaptability. In beef cattle, productivity starts to be affected by heat stress when environmental conditions allow an estimation of a THI > 75.ResultsResults showed a differing distribution of ticks on the body of individuals that varied according to the agroecological region. There was a significant effect of breed, sex, family, age and live weight on cattle tick burden. The lowest tick burden was observed in the ROMO breed (12.8 ± 2.6), while the highest tick burden was observed in CCC (31.8 ± 2.3), which were located in the same agroecological region. SM and ROMO animals with an AI > 2 had a higher tick burden than their counterparts that had an AI < 2.ConclusionsCattle breed, sex, age and live weight affect the tick burden in Bos taurus Colombian cattle breeds. The tick burden is higher in cattle with lower adaptability to heat stress. Moreover, it decreases as heat stress levels increase in a tropical environment. The interaction between tick burden and environmental heat stress can be affected by characteristics of the agroecological region itself, the breed and the genetic resistance of the individual tick, as well as the thermal adaptability of cattle.

Prediction of water intake to Bos indicus beef cattle raised under tropical conditions1.

Water is the most important nutrient in animal nutrition; however, water intake is rarely measured. The objective of this study was to determine whether previously published water intake (WI) equations for beef cattle would accurately predict WI from four experiments conducted under tropical conditions. The experiments were conducted from 2013 to 2015. Nellore (Bos indicus) growing bulls (Exps. 1, 2, and 3) and heifers (Exp. 4) were used in the feedlot trials. In all experiments, animals were fed for ad libitum DMI. The WI, animal performance, diet composition, and environmental data were collected. The prediction of WI using the current published WI equations was evaluated by regressing predicted and measured WI values. The regression was evaluated using the two-hypothesis test: H0: β0 = 0 and H0: β1 = 1 and Ha: not H0. If both null hypotheses were not rejected, it was concluded that the tested equation accurately estimated WI. To develop a WI prediction equation based on the input variables, a leave-one-out cross-validation method was proposed. The proposed equation was evaluated using similar methodology described above. All previously published eight equations overestimated WI of cattle used in the four experiments conducted in southeast Brazil. A possible explanation for the overestimate of WI is that previously published WI equations were generated from data collected from predominantly Bos taurus cattle raised under temperate climates. From the data collected from experiments conducted with Nellore cattle in southeast Brazil, the proposed equation (WI = 9.449 + 0.190 × MBW + 0.271 × TMAX -0.259 × HU + 0.489 × DMI, where the MBW is the metabolic BW (kg0.75), TMAX is the maximum temperature (°C), HU is the humidity (%) and DMI in kg/d), more accurately to predicts WI of cattle raised under tropical conditions.

First Molecular detection of Theileria annulata in Bangladesh.

In South Asia, Theileria annulata is known to be less pathogenic to local breeds of Bos indicus cattle comparing to Bos taurus cattle and some of mix breeds between them. Seroepidemiological surveys have revealed high sero-prevalence of T. annulata in asymptomatic local breeds of cattle in Bangladesh. Therefore, these asymptomatic infection in local breeds can be infectious sources to more sensitive breeds. In this study, 59 bloods of cattle showing no symptom were screened by species specific PCRs for hemoto-protozoan parasites, to prove the existence of T. annulata parasite in asymptomatic cattle in Bangladesh. The T. annulata infection was confirmed along with other parasitic species, and this is the first report of T. annulata DNA detection in Bangladesh.

Genotyping of Indigenous Cattle Breeds and their Exotic Crosses for beta -casein Milk Type using PCR-RFLP and Sequencing

The role of A1 and A2 s casein milk variants and human health is a subject of concern for scientific investigations. The status of A1/A2 s-casein variants in Bos taurus cattle breeds from several countries have shown presence of A1 variant in European cattle, which has been linked to range of illness. However, information on A1/A2 s-casein variants in Bos indicus and their crosses is limited. Bulls can influence the population structure more profoundly. Hence, the intend of the study was to know the prevalence of variants of s-casein (β-CSN2) in Gir and Kankrej, prominent Bos indicus breeds of the country and crossbred bulls (HF crossbreds) used for artificial insemination. Semen/ blood samples of 226 Gir, 88 Kankrej and 263 crossbred bulls and cows were collected from three semen stations and three non-government breeding farm, in Gujarat. PCR–RFLP and allele specific PCR analysis of the s casein region revealed all three genotypes suggesting prevalence of A1 variant in Gir and Kankrej also. Frequency of A1 allele in the indigenous breeds was much higher than believed earlier. We also report the first case of A1A1 Gir bull. This is probably the first report of prevalence of A1A1 genotype in any of the zebu Bos indius breeds. Crossbred cattle showed prevalence of both variants, A1 and A2 with higher frequency of A2. Further, allelic frequencies confirmed deviation from H-W equilibrium in HF crossbreds but not in Gir and Kankrej. The sequence analysis confirmed SNP ‘C’ to ‘A’ causing replacement of proline by histidine between A1 and A2 s casein. The present study confirmed the earlier theory that A2 allele of s casein is predominant in Bos indicus.

Complete mitogenome reveals genetic divergence and phylogenetic relationships among Indian cattle (Bos indicus) breeds

Indigenous cattle of India belong to the species, Bos indicus and they possess various adaptability and production traits. However, little is known about the genetic diversity and origin of these breeds. To investigate the status, we sequenced and analyzed the whole mitochondrial DNA (mtDNA) of seven Indian cattle breeds. In total, 49 single-nucleotide variants (SNVs) were identified among the seven breeds analyzed. We observed a common synonymous SNV in the COII gene (m.7583G > A) of all the breeds studied. The phylogenetic analysis and genetic distance estimation showed the close genetic relationship among the Indian cattle breeds, whereas distinct genetic differences were observed between Bos indicus and Bos taurus cattle. Our results indicate a common ancestor for European Zwergzebu breed and South Indian cattle. The estimated divergence time demonstrated that the Bos indicus and Bos taurus cattle lineages diverged 0.92 million years ago. Our study also demonstrates that ancestors of present zebu breeds originated in South and North India separately ∼30,000 to 20,000 years ago. In conclusion, the identified genetic variants and results of the phylogenetic analysis may provide baseline information to develop appropriate strategies for management and conservation of Indian cattle breeds.

Sex control by Zfy siRNA in the dairy cattle

Zinc-finger Y is located in the short arm of the Y-chromosome and is a highly conserved gene that plays an important role in spermatogenesis. The objective of this study was to investigate the influence of silencing the Zfy gene during spermatogenesis on Y-sperm formation and offspring sex determination in Bos taurus cattle. Three recombinant expression vectors pLL3.7/a, pLL3.7/b and pLL3.7/c were evaluated and only pLL3.7/a effectively silenced the Zfy gene. The pLL3.7/a recombinant expression vector was injected into bull testes, using three injections. Semen was collected and preserved by extending and freezing. The frozen semen was subsequently used in artificial insemination of cows during a breeding season in accordance with the production plan on the farm where the experiment was conducted. Results showed that, after exposure to pLL3.7/a, sperm motility decreased (P < 0.01), but the sperm density was similar (p > 0.05) to the non-treated control semen. Injection of pLL3.7/a resulted in 72.0% female offspring, and was greater than the 49.4% female calves in the control (P ＜ 0.01), Results from this research suggests that the Zfy gene plays a role in the process of Y-sperm formation, and Zfy siRNA is a potential useful approach to control sex of offspring in cattle.

Range Expansion of Fascioloides magna in North Carolina

In North Carolina, Odocoileus virginianus (White-tailed Deer) are the definitive natural hosts of Fascioloides magna (Giant Liver Fluke). Previous research identified the enzootic range of Giant Liver Fluke in North Carolina to be within the Tar River and Roanoke River Basins in Halifax and neighboring counties. Recent Giant Liver Fluke infections of Ovis aries (Domestic Sheep), Capra hircus (Domestic Goat), Lama glama (Llama), Vicugna pacos (Alpaca), and Bos taurus (Cattle) outside the historic enzootic range prompted us to investigate the current range of Giant Liver Fluke in North Carolina. From September 2014 to January 2015, we examined livers from hunter-harvested White-tailed Deer within 16 North Carolina counties. We detected Giant Liver Fluke in livers from 5 counties, with an overall prevalence of 10.3%. Besides reporting the first Giant Liver Fluke infections of livestock in North Carolina, we documented new geographic localities (Cabarrus, Franklin, Mecklenburg, Union, Wake, and Washington counties) for Giant Liver Fluke. An increased impact on North Carolina livestock is likely with the possible range expansion of Giant Liver Fluke, which may be related to the increase in populations of White-tailed Deer.

Variations in mitochondrial cytochrome b region among Ethiopian indigenous cattle populations assert Bos taurus maternal origin and historical dynamics.

ObjectiveThis study was carried out to assess the haplotype diversity and population dynamics in cattle populations of Ethiopia.MethodsWe sequenced the complete mitochondrial cytochrome b gene of 76 animals from five indigenous and one Holstein Friesian×Barka cross bred cattle populations.ResultsIn the sequence analysis, 18 haplotypes were generated from 18 segregating sites and the average haplotype and nucleotide diversities were 0.7540±0.043 and 0.0010±0.000, respectively. The population differentiation analysis shows a weak population structure (4.55%) among the populations studied. Majority of the variation (95.45%) is observed by within populations. The overall average pair-wise distance (F ST) was 0.049539 with the highest (F ST = 0.1245) and the lowest (F ST = 0.011) F ST distances observed between Boran and Abigar, and Sheko and Abigar from the indigenous cattle, respectively. The phylogenetic network analysis revealed that all the haplotypes detected clustered together with the Bos taurus cattle and converged to a haplogroup. No haplotype in Ethiopian cattle was observed clustered with the reference Bos indicus group. The mismatch distribution analysis indicates a single population expansion event among the cattle populations.ConclusionOverall, high haplotype variability was observed among Ethiopian cattle populations and they share a common ancestor with Bos taurus.

SNP Data Quality Control in a National Beef and Dairy Cattle System and Highly Accurate SNP Based Parentage Verification and Identification.

A major use of genetic data is parentage verification and identification as inaccurate pedigrees negatively affect genetic gain. Since 2012 the international standard for single nucleotide polymorphism (SNP) verification in Bos taurus cattle has been the ISAG SNP panels. While these ISAG panels provide an increased level of parentage accuracy over microsatellite markers (MS), they can validate the wrong parent at ≤1% misconcordance rate levels, indicating that more SNP are needed if a more accurate pedigree is required. With rapidly increasing numbers of cattle being genotyped in Ireland that represent 61 B. taurus breeds from a wide range of farm types: beef/dairy, AI/pedigree/commercial, purebred/crossbred, and large to small herd size the Irish Cattle Breeding Federation (ICBF) analyzed different SNP densities to determine that at a minimum ≥500 SNP are needed to consistently predict only one set of parents at a ≤1% misconcordance rate. For parentage validation and prediction ICBF uses 800 SNP (ICBF800) selected based on SNP clustering quality, ISAG200 inclusion, call rate (CR), and minor allele frequency (MAF) in the Irish cattle population. Large datasets require sample and SNP quality control (QC). Most publications only deal with SNP QC via CR, MAF, parent-progeny conflicts, and Hardy-Weinberg deviation, but not sample QC. We report here parentage, SNP QC, and a genomic sample QC pipelines to deal with the unique challenges of >1 million genotypes from a national herd such as SNP genotype errors from mis-tagging of animals, lab errors, farm errors, and multiple other issues that can arise. We divide the pipeline into two parts: a Genotype QC and an Animal QC pipeline. The Genotype QC identifies samples with low call rate, missing or mixed genotype classes (no BB genotype or ABTG alleles present), and low genotype frequencies. The Animal QC handles situations where the genotype might not belong to the listed individual by identifying: >1 non-matching genotypes per animal, SNP duplicates, sex and breed prediction mismatches, parentage and progeny validation results, and other situations. The Animal QC pipeline make use of ICBF800 SNP set where appropriate to identify errors in a computationally efficient yet still highly accurate method.

Exploring the association between polymorphisms at 3’UTR SLC11A1 gene microsatellites and resistance to tuberculosis: A case-control study in Bos taurus dairy cattle

Bovine tuberculosis is a contagious infectious disease that causes significant economic impact in dairy and meat farms throughout the world. Multiple factors, including host genome, determine the outcome of the infection. Several studies have associated polymorphisms at the two microsatellites (Ms) -Ms1 and Ms2- at the 3´unstranslated (UTR) region of the SLC11A1 bovine gene with innate resistance or susceptibility to some facultative intracellular bacterial infections, such as Brucella abortus and Mycobacterium avium subsp. paratuberculosis. Today, the few studies that investigated the association of those polymorphisms with innate resistance or susceptibility to tuberculosis in cattle, have shown opposite results. The aim of this study was to evaluate the role, if any, of the Ms1 and/or Ms2 polymorphisms at the 3´UTR of the SLC11A1 gene in Mycobacterium bovis infection phenotypes in Bos taurus dairy cattle. Jersey (n = 149) and Holstein (n = 427) cattle under risk of natural M. bovis infection were classified like controls (n = 326) and cases (n = 250) based on the response to caudal fold tuberculin skin test. Cattle population was genotyped by capillary electrophoresis based on polymorphisms in Ms1 and Ms2 at the 3´UTR SLC11A1 gene. The results presented here showed a lack of association (p > .05) between polymorphisms at the 3´UTR SLC11A1 gene and the response to tuberculin skin test in dairy Bos taurus cattle. Further studies are necessary to establish robustly genes or genome regions determining the innate R/S phenotype to Mycobacterium bovis.

Molecular characterization and differential mRNA expression profiling of Toll-like receptor-2 gene in Vechur (Bos indicus) and crossbred (Bos indicus X Bos taurus) cattle of Kerala in response to anthrax vaccination

Toll like receptors (TLRs) are type 1 transmembrane proteins expressed in almost all cell types and activate the innate immune system. The present study involved characterization and differential transcriptional expression profiling of Toll-like receptor-2 gene in Vechur (Bos indicus) and crossbred (Bos indicus X Bos taurus) cattle of Kerala in response to anthrax vaccination. Sequence analysis revealed 2355 bp long TLR2 open reading frame encoding 784 amino acids with a signal peptide of 20 amino acid residues. The sequence of Vechur TLR2 revealed 96–99% identity with other ruminant species. At amino acid level, 94–99% similarity was observed with other livestock species. Seven nucleotide variations were observed when compared with other Indian cattle and 17 variations with Bos taurus. The five non-synonymous mutations observed in Vechur as compared to Bos indicus (GenBank Acc. No. EU413951.1) were p.Gln149Pro, p.Ile335Thr, p.Lys.337Arg, p.Ser345Asn and p.Met605Thr. The eight non synonymous variations observed as compared to Bos taurus (GenBank Acc. No. NM174197.2) were p.Asp63Glu, p.Gly68Ser, p.Ile111Val, p.Phe127Leu, p.His326Gln, p.Asn417Ser, p.Arg563His and p.His665Gln. This is the first report about the full-length cDNA sequence and the single nucleotide variations of TLR2 gene of the Vechur cattle, the smallest cattle of the world. The prolonged upregulation of TLR2 mRNA in Vechur cattle as compared to Crossbred cattle post anthrax vaccination is suggestive of the greater immune response of this native cattle as compared to exotic cattle.

The complete mitochondrial genome of Indian cattle (Bos indicus)

India has 40 distinct zebuine cattle breeds with different adaptability and production traits. In the present study, we report the complete mitochondrial genome sequence of Indian cattle for the first time. The mitogenome contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and a control region (D-loop region). The phylogenetic analysis showed close genetic relationship among the Indian cattle breeds studied, where as, distinct genetic differences were observed between Bos indicus and Bos taurus cattle. Our results will expand genomic information for further studies on evolution, domestication and conservation of indigenous cattle breeds in India.

Complement C3 and anti-testosterone antibody in the 150 kDa Bali cattle (Bos sondaicus/javanicus) subordinate follicular fluid peptide observed using MALDI-TOF/TOF-MS

Objective : This study aimed to elucidate the proteome profile of the 150 kDa protein isolated from the subordinate follicle of Bali cattle ( Bos sondaicus / javanicus ). Some researchers have revealed several factors in the follicular subordinate with a 150 kDa protein substance, which play important roles in the bovine ovulation. Materials and methods : In the present study, subordinate follicles (~ 5 mm in diameter) were collected from 10 female Bali cattle from slaughterhouses in Taliwang, Sumbawa of West Nusa Tenggara Province, Indonesia. The follicular liquid was pooled; fractionated using SDSPAGE 10%, the 150 kDa band was sliced and then analyzed using MALDI-TOF/TOF-MS. Results : Mascot search results significantly revealed the presence of four species of proteins/peptides. Of the four peptides, two were predominant i.e. complement C3 and anti-testosterone antibody, which both were 100% identical to complement C3 and anti-testosterone antibody of Bos Taurus cattle. Conclusion : Complement C3 and anti-testosterone antibody are present in the follicle fluid of Bos sondaicus/javanicus cows. These findings are novel in Bali cattle follicles. http://doi.org/10.5455/javar.2018.e240

Cattle Tick Rhipicephalus microplus-Host Interface: A Review of Resistant and Susceptible Host Responses.

Ticks are able to transmit tick-borne infectious agents to vertebrate hosts which cause major constraints to public and livestock health. The costs associated with mortality, relapse, treatments, and decreased production yields are economically significant. Ticks adapted to a hematophagous existence after the vertebrate hemostatic system evolved into a multi-layered defense system against foreign invasion (pathogens and ectoparasites), blood loss, and immune responses. Subsequently, ticks evolved by developing an ability to suppress the vertebrate host immune system with a devastating impact particularly for exotic and crossbred cattle. Host genetics defines the immune responsiveness against ticks and tick-borne pathogens. To gain an insight into the naturally acquired resistant and susceptible cattle breed against ticks, studies have been conducted comparing the incidence of tick infestation on bovine hosts from divergent genetic backgrounds. It is well-documented that purebred and crossbred Bos taurus indicus cattle are more resistant to ticks and tick-borne pathogens compared to purebred European Bos taurus taurus cattle. Genetic studies identifying Quantitative Trait Loci markers using microsatellites and SNPs have been inconsistent with very low percentages relating phenotypic variation with tick infestation. Several skin gene expression and immunological studies have been undertaken using different breeds, different samples (peripheral blood, skin with tick feeding), infestation protocols and geographic environments. Susceptible breeds were commonly found to be associated with the increased expression of toll like receptors, MHC Class II, calcium binding proteins, and complement factors with an increased presence of neutrophils in the skin following tick feeding. Resistant breeds had higher levels of T cells present in the skin prior to tick infestation and thus seem to respond to ticks more efficiently. The skin of resistant breeds also contained higher numbers of eosinophils, mast cells and basophils with up-regulated proteases, cathepsins, keratins, collagens and extracellular matrix proteins in response to feeding ticks. Here we review immunological and molecular determinants that explore the cattle tick Rhipicephalus microplus-host resistance phenomenon as well as contemplating new insights and future directions to study tick resistance and susceptibility, in order to facilitate interventions for tick control.

Predicting the effects of the single nucleotide polymorphism A122V on CXC chemokine receptor type 1 of Bos taurus (Artiodactyla: Bovidae) cattle by in silico analyses

Este estudo objetivou predizer bioquimicamente as estruturas primárias e secundárias da proteína receptora de quimiocina CXCR1 bovina não polimórfica e polimórfica carreando o polimorfismo A122V por análises in silico. Duas sequências da proteína CXCR1 de bovino Bos taurus foram selecionadas a partir da base de dados de sequências de proteínas UniProtKB/Swiss-Prot: a) uma sequência não polimórfica (A7KWG0), contendo o aminoácido alanina (A) na posição 122, e b) uma sequência polimórfica, apresentando o aminoácido valina (V) na mesma posição. As estruturas primárias e secundárias da proteína foram preditas empregando os programas ProtParam e Chou &amp; Fasman Protein Secondary Structure Prediction CFSSP. Diferenças nos parâmetros físicos e químicos não foram previstas a partir da estrutura primária de ambas as proteínas analisadas. A presença de um domínio helicoidal, situado nas posições 100 e 150, foi exclusivamente encontrada na proteína CXCR1 não polimórfica. Resíduos de aminoácidos de propriedades bioquímicas variáveis foram detectados na posição 122 na proteína CXCR1 dos ruminantes e humana, sugerindo que esse peptídeo é altamente polimórfico em vertebrados. Os resultados aqui descritos predizem diferenças no padrão da estrutura secundária da proteína CXCR1 bovina não polimórfica e polimórfica A122V empregando ferramentas de Bioinformática.

Effect of heat stress on rumen temperature of three breeds of cattle.

Thirty-six steers (12 of each Angus, Charolais, and Brahman) with an initial BW of 318.5±6.7kg were used in a 130-day study. Two treatments were imposed: un-shaded and shaded (3m2/animal; 90% solar block shade cloth). On day 1, steers were administered with rumen temperature boluses. Rumen temperatures (T RUM) were obtained at 10min intervals over the duration of the study to determine differences in T RUM between Bos indicus and Bos taurus cattle. Six feedlot pens (162m2) were used with six steers (2/breed) per pen with three pens/treatment. Ambient dry bulb temperature (T A; °C), relative humidity (RH; %), wind speed (WS; m/s) and direction, and solar radiation (SR; W/m2) were recorded at 10min intervals. Rainfall (mm) was collected daily at 0900h. From these data, black globe temperature (BGT; °C), temperature humidity index (THI), heat load index (HLI), and accumulated heat load (AHL) were calculated. Individual T RUM were converted to an hourly average and then mean hourly T RUM were converted to a mean within hour T RUM across the 130days. Rumen temperatures were analyzed using an autoregressive repeated measures model. The model analyzed the effect of breed (P<0.0002), treatment (P=0.3543), time of day (hour, h; P<0.0001), breed × treatment (P<0.3683), breed × h (P<0.0001), treatment × h (P<0.0001), breed × treatment × h (P=0.0029), pen within treatment (P=0.0195), and animal × breed × treatment within pen (P=0.1041). Furthermore, there were breed × treatment × hour differences in T RUM (P=0.0036), indicating that Bos indicus and Bos taurus regulate T RUM differently.

The use of toxicokinetics and exposure studies to show that carprofen in cattle tissue could lead to secondary toxicity and death in wild vultures

Veterinary medicines can be extremely damaging to the environment, as seen with the catastrophic declines in Gyps vulture in South Asia due to their secondary exposure to diclofenac in their primary food source. Not surprisingly, concern has been raised over other similar drugs. In this study, we evaluate the toxicity of carprofen to the Gyps vulture clade through plasma pharmacokinetics evaluations in Bos taurus cattle (their food source) and Gyps africanus (a validated model species); tissue residues in cattle; and the effect of carprofen as a secondary toxicant as both tissue-bound residue or pure drug at levels expected in cattle tissues. Carprofen residues were highest in cattle kidney (7.72 ± 2.38 mg/kg) and injection site muscle (289.05 ± 98.96 mg/kg of dimension of 5 × 5 × 5 cm). Vultures exposed to carprofen as residues in the kidney tissue or pure drug equivalents showed no toxic signs. When exposed to average injection site concentrations (64 mg/kg) one of two birds died with evidence of severe renal and liver damage. Toxicokinetic analysis revealed a prolonged drug half-life of 37.75 h in the dead bird as opposed to 13.99 ± 5.61 h from healthy birds dosed intravenously at 5 mg/kg. While carprofen may generally be harmless to Gyps vultures, its high levels at the injection site in treated cattle can result in lethal exposure in foraging vultures, due to relative small area of tissue it is found therein. We thus suggest that carprofen not be used in domesticated ungulates in areas where carcasses are accessible or provided to vultures at supplementary feeding sites.