RESUMO
There are no studies regarding the estimation of genetic parameters and genetic trends for reproductive traits and somatic cells in goats. Their knowledge allows optimization of selection schemes. The objective of this study was to estimate genetic parameters and genetic and phenotypic trends for age at first kidding (AFK), kidding interval (KIN) and somatic cell score (SCS). Analyses were conducted within and across seven US goat breeds, namely, Nubian (NU), Alpine (AL), LaMancha (LM), Toggenburg (TO), Saanen (SA), Nigerian Dwarf (ND) and Oberhasli (OB), and a set of all of these breeds (AB). The restricted maximum likelihood methodology and trivariate animal models were used. Genetic and phenotypic trends were estimated using regression models. The average and standard deviation of AFK, KIN and SCS for AB were 573.6 ± 178.5 days, 418.8 ± 125.5 days and 4.67 ± 2.23 Log2, respectively. The heritabilities (h2) and standard errors of AFK, KIN and SCS for AB were 0.28 ± 0.02, 0.04 ± 0.02 and 0.22 ± 0.01, respectively. The h2 ranged from 0.15 (SA) to 0.37 (NU) for AFK, from 0.04 (AB) to 0.10 (AL) for KIN, and from 0.11 (TO) to 0.26 (LM and ND) for SCS. Genetic correlations between AFK and KIN and between AFK and SCS for AB were positive and weak (0.07 and 0.12, respectively) but significant (P < 0.01). Genetic correlations between SCS and KIN were significant (P < 0.01) for all the breeds and ranged from -0.15 (NU) to 0.44 (AL). Genetic correlations between AFK and SCS in the NU and AL breeds were similar (approximately 0.21). A positive genetic trend was found for KIN in the SA breed, which caused an increase in the number of days between consecutive kiddings. The genetic trend of SCS for the NU, AL and ND breeds was negative and decreased annually, which is beneficial for producers. These first results show the intensity and direction of some favorable/unfavorable relationships between AFK or KIN and SCS Log2 in some U.S. goat genetic groups.
Assuntos
Cabras , Reprodução , Animais , Cabras/genética , Feminino , Cruzamento , Fenótipo , Estados Unidos , Masculino , Indústria de LaticíniosRESUMO
Background: The aim of the present study was to describe the presence of co-infection by Toxoplasma gondii and Neospora caninum in goats reared in extensive systems from Mexico. Materials and Methods: A cross-sectional study was conducted to determine the frequency of T. gondii and N. caninum, by detecting antibodies to each parasite by mean commercial ELISA kits. A total of 176 blood samples were randomly collected from mature females reared in extensive system herds from 20 municipalities of state of Guanajuato, Mexico. Results: The general seroprevalence was 23.9 and 21.0% for T. gondii and N. caninum, respectively, while co-infection rate was 3.6%. For geographic and environmental variables, no differences were observed among T. gondii and coinfection; however, it was observed that altitude, annual precipitation, annual average temperature, and rainy period showed significant differences with N. caninum seropositive goats. Conclusion: The seroprevalence of both parasites was appreciated in most of the studied herds. The present study is the first report of T. gondii and N. caninum co-infection in goats from extensive herds in Mexico.
Assuntos
Coccidiose , Coinfecção , Doenças das Cabras , Cabras , Neospora , Toxoplasma , Toxoplasmose Animal , Animais , Coccidiose/veterinária , Coccidiose/epidemiologia , Coccidiose/parasitologia , México/epidemiologia , Toxoplasma/imunologia , Doenças das Cabras/epidemiologia , Doenças das Cabras/parasitologia , Toxoplasmose Animal/epidemiologia , Toxoplasmose Animal/parasitologia , Coinfecção/epidemiologia , Coinfecção/veterinária , Coinfecção/parasitologia , Estudos Soroepidemiológicos , Feminino , Estudos Transversais , Anticorpos Antiprotozoários/sangueRESUMO
The aim of this study was to describe the morphology and estimate live weight from body measurements of Socorro Island Merino lambs. A group of Socorro Island Merino lambs was recorded from birth to year for live weight, rump width, rump length, withers height, body length, cannon bone perimeter, and chest girth, width, and depth. The effect of the lamb type on body measurements and live weight was analyzed using ANOVA, Pearson's correlation analysis was performed to estimate the relationship between body measurements and live weight, multiple linear regressions were fitted to obtain prediction equations of live weight from the body measurements and finally, chest girth was used to generate prediction equations using linear and exponential models. At birth and at year, differences were observed in body measurements, especially those related to the thoracic region, with crossbred males showing the highest values. Live weight was correlated with almost all the body measurements, with the highest coefficients observed with chest girth, chest width, and chest depth. Live weight can be accurately predicted from multiple regression equations using several body measurements, but using only chest girth (CG) as a predictor, the exponential equation W0-365 = 0.9142 exp(0.0462 CG) showed the best accuracy.
RESUMO
Records of 3716 Nubian goats from the United States (US) were analyzed to estimate relationships between fourteen conformation traits (CT) with lactation average somatic cell score (ASCS). To analyze ASCS, a mixed model was implemented. Linear and quadratic effects of CT traits, days in milk (DIM), and kidding age in months (KA) were considered as fixed covariates, and herd-year (HY) of kidding as a random effect. Correlation coefficients between CT traits and ASCS adjusted for HY and linear and quadratic KA effects were also obtained. The average ± standard deviations for ASCS, DIM, and milk yield were 5.17±0.54 Log2, equivalent to 451.3 cells × 103/mL, 266.3±52.1 days, and 776.3±280.4 kg per lactation, respectively. Significant non-linear relationships with an intermediate maximum were found between ASCS with teat diameter and medial suspensory ligament, while linear relationships were observed with stature, strength, rump width, fore udder attachment, udder depth, teat diameter, teat placement, and medial suspensory ligament. The model explained 53.7% of the ASCS variability, but the contribution of each type variable to increase the coefficient of determination was low (<0.52%). Herd-year explained a large proportion of the variation of ASCS (38.4%). All estimated correlations between CT and ASCS had low values, from −0.04 to 0.11, but most were significant. The results of this study show that conformation traits have few opportunities to contribute phenotypically to assess somatic cell score in Nubian goats.
Assuntos
Animais , Feminino , Cabras/microbiologia , Glândulas Mamárias Animais/microbiologia , Células Produtoras de Anticorpos , Modelos EstatísticosRESUMO
Coenzyme Q9 (COQ9), a coenzyme Q (CoQ) precursor, is an essential component of the mitochondrial electron transport chain that drives adenosine triphosphate production. COQ9 polymorphism 18:25527339 is characterized by substitution of guanine (allele G) for adenine (allele A), which modifies the function of the protein encoded by the gene. In Holsteins, allele A has been associated with better reproductive performance in terms of the conception rate, number of services per conception (SPC) and days open (DO). The signal transducer and activator of transcription (STAT) protein is a transcription factor activated in the presence of cytokines and growth factors. STAT5A polymorphism 19:42407732 in exon 8 has been associated with higher fertility and embryonic survival rates. The objective of this study was to determine the relationship of COQ9 and STAT5A polymorphisms with reproductive parameters [calving to first heat interval (CFHI), DO and SPC]. Blood samples were taken from 112 lactating Holstein from a herd in México for allele genotyping by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). To estimate the association between reproductive parameters and genotypes, a linear mixed-effect model was performed. The COQ9 AG genotype was associated significantly with lower SPC (P<0.05) but not with DO or CFHI. No significant association with any reproductive parameter was found for STAT5A. Our findings suggest that the COQ9 18:25527339 polymorphism is a useful molecular marker for improvement of reproductive performance in dairy herds.
RESUMO
BACKGROUND: Staphylococcus aureus is one of the main microorganisms that causes bovine mastitis, and its well-known virulence characteristics and interactions with the environment are used to aid the design of more efficient therapies. OBJECTIVES: To determine whether the virulence traits, such as antibiotic resistance and biofilm-forming and internalization abilities, of S. aureus isolated from bovine mastitis are related to dairy production system types. METHODS: The study was performed in the Mexican states of Guanajuato and Michoacan. Semi-intensive dairy farms (SIDFs) and family dairy farms (FDFs) (454 and 363 cows, respectively) were included. The 194 milk samples from mastitis affected quarters were collected and 92 strains of S. aureus were isolated and identified by biochemical and molecular tests. Antibiotic resistance, biofilm and internalization assays were performed on 30 randomly selected isolated strains to determine virulence traits, and these strains were equally allocated to the 2 dairy production systems. RESULTS: All 30 selected strains displayed a high degree of resistance (50%-91.7%) to the antibiotics tested, but no significant difference was found between SIDF and FDF isolates. S. aureus strains from SIDFs had an average biofilm forming capacity of up to 36% (18.9%-53.1%), while S. aureus strains from FDFs registered an average of up to 53% (31.5%-77.8%) (p > 0.05). Internalization assays revealed a higher frequency of internalization capacity for strains isolated from FDFs (33.3%) than for those isolated from SIDFs (6.7%) (p > 0.05). fnbpA gen was detected in 46.6% of FDF strains and 33.3% of SIDF strains, and this difference was significant (p < 0.05). CONCLUSIONS: Our findings show that the virulence traits of S. aureus isolates analyzed in this study, depend significantly on several factors, such as phenotype, genotype, and environmental conditions, which are significantly related to dairy production system type and daily management practices.
Assuntos
Biofilmes , Indústria de Laticínios/classificação , Farmacorresistência Bacteriana , Mastite Bovina/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/fisiologia , Staphylococcus aureus/patogenicidade , Animais , Biofilmes/crescimento & desenvolvimento , Bovinos , Farmacorresistência Bacteriana/genética , Fazendas , Feminino , Mastite Bovina/epidemiologia , México/epidemiologia , Prevalência , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , VirulênciaRESUMO
Coenzyme Q9 (COQ9), a coenzyme Q (CoQ) precursor, is an essential component of the mitochondrial electron transport chain that drives adenosine triphosphate production. COQ9 polymorphism 18:25527339 is characterized by substitution of guanine (allele G) for adenine (allele A), which modifies the function of the protein encoded by the gene. In Holsteins, allele A has been associated with better reproductive performance in terms of the conception rate, number of services per conception (SPC) and days open (DO). The signal transducer and activator of transcription (STAT) protein is a transcription factor activated in the presence of cytokines and growth factors. STAT5A polymorphism 19:42407732 in exon 8 has been associated with higher fertility and embryonic survival rates. The objective of this study was to determine the relationship of COQ9 and STAT5A polymorphisms with reproductive parameters [calving to first heat interval (CFHI), DO and SPC]. Blood samples were taken from 112 lactating Holstein from a herd in México for allele genotyping by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). To estimate the association between reproductive parameters and genotypes, a linear mixed-effect model was performed. The COQ9 AG genotype was associated significantly with lower SPC (P<0.05) but not with DO or CFHI. No significant association with any reproductive parameter was found for STAT5A. Our findings suggest that the COQ9 18:25527339 polymorphism is a useful molecular marker for improvement of reproductive performance in dairy herds.
Assuntos
Feminino , Animais , Bovinos , Bovinos , Coenzimas/química , Fertilidade , Polimorfismo Genético , MitocôndriasRESUMO
Coenzyme Q9 (COQ9), a coenzyme Q (CoQ) precursor, is an essential component of the mitochondrial electron transport chain that drives adenosine triphosphate production. COQ9 polymorphism 18:25527339 is characterized by substitution of guanine (allele G) for adenine (allele A), which modifies the function of the protein encoded by the gene. In Holsteins, allele A has been associated with better reproductive performance in terms of the conception rate, number of services per conception (SPC) and days open (DO). The signal transducer and activator of transcription (STAT) protein is a transcription factor activated in the presence of cytokines and growth factors. STAT5A polymorphism 19:42407732 in exon 8 has been associated with higher fertility and embryonic survival rates. The objective of this study was to determine the relationship of COQ9 and STAT5A polymorphisms with reproductive parameters [calving to first heat interval (CFHI), DO and SPC]. Blood samples were taken from 112 lactating Holstein from a herd in México for allele genotyping by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). To estimate the association between reproductive parameters and genotypes, a linear mixed-effect model was performed. The COQ9 AG genotype was associated significantly with lower SPC (P<0.05) but not with DO or CFHI. No significant association with any reproductive parameter was found for STAT5A. Our findings suggest that the COQ9 18:25527339 polymorphism is a useful molecular marker for improvement of reproductive performance in dairy herds.(AU)
Assuntos
Animais , Feminino , Bovinos , Polimorfismo Genético , Coenzimas/química , Bovinos , Fertilidade , MitocôndriasRESUMO
Staphylococcus aureus is an opportunistic pathogen that may cause severe infections in livestock, and represents the major cause of mastitis in dairy cows. Currently, instead of using antibiotics, new strategies are sought to reduce this clinical health problem. The aim of this study was to determine the efficacy of phage therapy to kill S. aureus strains obtained from farms located at the State of Guanajuato, México. Thirty-six S. aureus strains from cow milk with subclinical mastitis were isolated and identified, and the susceptibility to antibiotics and four phages also isolated in this work was tested. It was found that more of 90% of S. aureus isolates were not susceptible to six or more antibiotics, and 100% were resistant to penicillin, dicloxacillin, cefotaxime, ampicillin and cephalothin, and 81 and 77%, to tetracycline and cefuroxime, respectively. Fortunately, 100% of S. aureus isolates were susceptible to phages used in this work, which was detected as clear zones using specific phage. It was shown for the first time, that phages used in this study are active against pathogenic S. aureus and might be incorporated into the therapy as an important tool for the control of staphylococcal bovine mastitis, specially to antibiotic-resistant S. aureus strains isolated in farm located at the state of Guanajuato, México; and its use might be extended to other regions inside or outside the country.
Assuntos
Antibacterianos/farmacologia , Bacteriófagos/fisiologia , Farmacorresistência Bacteriana , Mastite Bovina/prevenção & controle , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/virologia , Animais , Bovinos , Feminino , Técnicas In Vitro , México , Infecções Estafilocócicas/prevenção & controleRESUMO
Dirofilaria repens is the causative zoonotic agent of subcutaneous dirofilariosis. Although the American continent is considered currently free of D. repens infections, in the past few years there have been some reports suggesting the presence of this agent in the Americas. In Guanajuato, Mexico, there is a report of the presence of D. repens. To determine whether this parasite is really present in Guanajuato, a total of 177 EDTA blood samples from dogs were tested using the modified Knott's technique. Using this technique, we found 15 positive samples, which were then analyzed using the PCR technique, with a panfilarial set of primers and a specific primer pair for D. repens. In one sample, the expected band was present and the corresponding amplicon, sequenced, displayed a 100% identity to D. repens, confirming the presence of this exotic and zoonotic filarial species in the municipality of Silao, Guanajuato, Mexico.