Dairy Cattle In Brazil Research Articles

Long-Term Co-Circulation of Host-Specialist and Host-Generalist Lineages of Group B Streptococcus in Brazilian Dairy Cattle with Heterogeneous Antimicrobial Resistance Profiles.

Group B Streptococcus (GBS) is a major cause of contagious bovine mastitis (CBM) in Brazil. The GBS population is composed of host-generalist and host-specialist lineages, which may differ in antimicrobial resistance (AMR) and zoonotic potential, and the surveillance of bovine GBS is crucial to developing effective CBM control and prevention measures. Here, we investigated bovine GBS isolates (n = 156) collected in Brazil between 1987 and 2021 using phenotypic testing and whole-genome sequencing to uncover the molecular epidemiology of bovine GBS. Clonal complex (CC) 61/67 was the predominant clade in the 20th century; however, it was replaced by CC91, with which it shares a most common recent ancestor, in the 21st century, despite the higher prevalence of AMR in CC61/67 than in CC91, and high selection pressure for AMR from indiscriminate antimicrobial use in the Brazilian dairy industry. CC103 also emerged as a dominant CC in the 21st century, and a considerable proportion of herds had two or more GBS strains, suggesting poor biosecurity and within-herd evolution due to the chronic nature of CBM problems. The majority of bovine GBS belonged to serotype Ia or III, which was strongly correlated with CCs. Ninety-three isolates were resistant to tetracycline (≥8 μg/mL; tetO = 57, tetM = 34 or both = 2) and forty-four were resistant to erythromycin (2.0 to >4 μg/mL; ermA = 1, ermB = 38, mechanism unidentified n = 5). Only three isolates were non-susceptible to penicillin (≥8.0 μg/mL), providing opportunities for improved antimicrobial stewardship through the use of narrow-spectrum antimicrobials for the treatment of dairy cattle. The common bovine GBS clades detected in this study have rarely been reported in humans, suggesting limited risk of interspecies transmission of GBS in Brazil. This study provides new data to support improvements to CBM and AMR control, bovine GBS vaccine design, and the management of public health risks posed by bovine GBS in Brazil.

Outbreak of persistently infected heifer calves with bovine viral diarrhea virus subgenotypes 1b and 1d in a BVDV-vaccinated open dairy herd

Bovine viral diarrhea virus (BVDV) infection has a significant economic impact on beef and dairy industries worldwide. Fetal infection with a non-cytopathic strain may lead to the birth of persistently infected (PI) offspring, which is the main event in the epidemiological chain of BVDV infection. This report describes the birth of 99 BVDV-PI heifer calves within 52 days of birth in a regular BVDV-vaccinated Brazilian dairy cattle herd and the subgenotypes of the infecting field strains. This study was conducted in a high-yielding open dairy cattle herd that frequently acquired heifers from neighboring areas for replacement. The farm monitors the birth of PI calves by screening all calves born using an ELISA (IDEXX) for BVDV antigen detection. All calves aged 1–7 days were evaluated. For positive and suspected results, the ELISA was repeated when the calves were close to one month old. A total of 294 heifer calves were evaluated between February and March 2021. Of these, 99 (33.7 %) had positive ELISA results and were considered PI calves. To evaluate the predominant BVDV species and subgenotypes in this outbreak, whole blood samples were collected from 31 calves born during the study period. All samples were submitted to the RT-PCR assay for the partial amplification of the BVDV 5′-UTR region, and these amplicons were subjected to nucleotide sequencing. Phylogenetic analysis identified BVDV-1b and BVDV-1d in 16 and 13 heifer calves, respectively. In two calves, it was not possible to determine the BVDV-1 subgenotype. Detection of PI animals and monitoring of circulating BVDV subgenotype strains are central to disease control. This study shows that regular BVDV vaccination alone may be insufficient to prevent BVDV infection in high-yielding open dairy cattle herds. Other biosecurity measures must be adopted to avoid the purchase of cattle with acute infections by BVDV or BVDV-PI, which can cause a break in the health profile of the herd and economic losses.

Association between coa gene and enterotoxin gene in S. aureus from dairy cattle in Brazil

Staphylococcus aureus is an important agent in bovine mastitis, and some specific virulence factors may be implicated in this disease. Therefore, this study aimed to investigate the importance of the presence of coagulase, superantigens, genotypic and phenotypic resistance, and pulsotypes in 65 S. aureus isolates from bovine clinical and subclinical mastitis in the Southeast of Brazil. A high correlation was observed between the genes coa and see, as well as between the sei and the see and seh. High resistance rates were observed for penicillin (95.4%), tetracycline (89.2%), cefoxitin (86.1%), oxacillin (84.6%), erythromycin (84.6%), clindamycin (84.6%), chloramphenicol (81.5%), ceftriaxone (80.0%), and ampicillin (80.0%). Analysis of antimicrobial resistance profiles showed that 89.2% of isolates were multi-drug-resistant. No mecA-positive S. aureus isolates were detected. It was observed that seven isolates were resistant to all the β-lactam tested while being susceptible to cefoxitin, which could be indicative of borderline methicillin resistance in S. aureus⁠. High genetic diversity with no specific virulence profile being predominant was observed. Thus, this study observed a high correlation between the coa and enterotoxins genes, and demonstrates that there is no predominant pulsotype causing intramammary infection and that there is a high rate of antibiotic resistance in S. aureus isolates from dairy farms in the southeast regions of Brazil.

Strategies to Maximize Kernel Processing in a Brazilian Vitreous Endosperm Hybrid

Whole-plant corn silage (WPCS) is a major source of forage for dairy cattle in Brazil. Improved kernel processing may be especially advantageous when feeding corn hybrids with vitreous endosperms. Two experiments were conducted to evaluate the effects of the theoretical length of cut (TLOC) and ensiling time on WPCS particle size and kernel processing with two types of forage harvesters. In the first trial, the plant was harvested by a pull-type forage harvester (PTFH) at TLOCs of 3, 6 and 9 mm. In the second trial, the harvesting was performed by a self-propelled forage harvester (SPFH) at TLOCs of 6, 12 and 18 mm, with a roll gap of 3 mm. The WPCS were stored for 0, 35 and 140 days. In the PTFH trial, the TLOCs of 3 and 6 mm did not affect the WPCS particle size distribution and mean particle length (MPL). However, the TLOC of 9 mm increased the MPL. The increase in the TLOC with the SPFH led to a higher MPL and percentage of long particles. The ensiling time increased the MPL and long particles only for the WPCS harvested by the SPFH. The strategy of reducing the TLOC with the SPFH increased the percentage of kernels smaller than 4.75 mm. Furthermore, the TLOC of 6 mm led to the best kernel processing with the SPFH. The ensiling time reduced the particle size of the kernel fractions for both forage harvesters. The corn silage processing score was improved with 140 days of ensiling with the SPFH. These findings suggest that increasing the ensiling time and a low TLOC in SPFHs (6 mm) may be good strategies to increase kernel damage and starch digestibility in WPCS.

Evaluation of the impact of COVID-19 on dairy cattle farming in Brazil

COVID-19 has brought numerous challenges for the dairy industry. This research aimed to analyze the impact of the COVID-19 pandemic on Brazilian dairy cattle farming. The study was conducted from December 2020 to February 2021 via Google Forms® platform. Data obtained were tabulated and evaluated using descriptive and multivariate analysis, Shapiro-Wilk, Kruskall-Wallis, Variance Analysis (ANOVA), and Dunn’s post-hoc comparison. The study was approved by the Committee for Ethics in Research with Human. In total, 73 viable responses were obtained, with participations from the Brazilian regions Midwest, Northeast, South, and Southeast. Among the biosecurity measures adopted during the study, 86% of farm employees began to sanitize their hands more often to prevent the transmission of COVID-19. Use of masks during work was required all the time during work by employees in 17 properties (23%), although the use of masks was not required in 40 (55%) farms and 16 properties required them during part of the work (22%). Regarding milk production, 99% of the respondents had no problems with milk collection and more than half of the producers had difficulties in acquiring animals. Moreover, thirty-seven percent of the interviewees said they were unaware of how the virus was transmitted. Regarding the size of the dairy farms, small farms were more likely to have no veterinary medical care. The pandemic brought positive and negative impacts to dairy properties, which was influenced by the number of animals, the presence of veterinary care, and average daily milk production.

Sustainability indicators for Brazilian dairy livestock: the perception of professionals in the sector

The objective of this study was to analyze the perceptions of professionals in relation to the importance of indicators used to assess the sustainability of Brazilian dairy cattle. A survey method was used through a questionnaire. The target audience was professionals related to dairy cattle: researchers, professors, consultants, farmers, and other professionals. The total number of respondents to the survey was 347. Cluster analysis resulted in the formation of four distinct groups: G1 (“Holistic”), participants agreed that all indicators [...]

Dairy Cattle Euthanasia-Focus Groups Exploring the Perspectives of Brazilians Working in the Dairy Cattle Industry.

Simple SummaryEuthanasia is the practice of ending the life of an animal that has no possibility of improvement and aims at minimizing suffering and mitigating poor animal welfare. Concerns regarding animal welfare are an international priority given that euthanasia standard requirements have the potential to impact the global trade of animal products. To ensure positive dairy cattle welfare by minimizing suffering via euthanasia, we must first understand how euthanasia is viewed within the Brazilian dairy community and identify barriers that prevent timely euthanasia from occurring. Therefore, we aimed to explore perspectives and attitudes about euthanasia specific to the Brazilian dairy industry using focus groups. Upon analysis of the discussions, three main themes were revealed: Euthanasia Training and Farm and Human Components. Several subthemes are discussed. The lack of nationally recognized euthanasia guidelines for dairy cattle paired with ineffective and inaccessible euthanasia tools makes it difficult for dairy veterinarians to implement humane protocols for on-farm euthanasia. In addition, logistical factors, particularly, the financial cost of euthanasia and the human–animal bond, play a role in the failure to perform euthanasia when warranted. Future studies should focus on the development of science-based standards and producer training to improve the consistency of on-farm euthanasia in Brazilian dairy operations.The objective of this study was to explore perspectives and attitudes about euthanasia specific to the Brazilian dairy cattle industry. Twenty-five Brazilian citizens (13 veterinarians, 4 animal scientists, 3 professors, 3 researchers, 1 dairy owner, and 1 caretaker) participated in one of three focus groups conducted and recorded online (10, 8, and 7 participants per group). Questions regarding euthanasia were posed by a moderator, and the focus group discussions were then transcribed verbatim for analysis. After the initial data analysis, themes were evaluated and collapsed into three major categories: Euthanasia Training and Farm and Human Components. A complex interconnection between the three main themes and multiple subthemes specific to dairy cattle euthanasia was also revealed. The lack of nationally recognized euthanasia guidelines for dairy cattle paired with ineffective and inaccessible euthanasia tools makes it difficult for dairy veterinarians to implement humane protocols for on-farm euthanasia. In addition, logistical factors, particularly, the financial cost of euthanasia and the human–animal bond, play a role in the failure to perform euthanasia when warranted. Future studies should focus on the development of science-based standards and producer training to improve the consistency of on-farm euthanasia in Brazilian dairy operations.

Factors affecting length of productive life of Brazilian Holstein cows assessed using survival analysis

Context Length of productive life is defined as the number of days from first calving to the last day of milking records, when the cow is no longer sufficiently productive. Although it has economic implications, length of productive life has not yet been included in Brazilian dairy cattle breeding programs because it depends on other traits such as age at first calving, milk production level and disease occurrence. In addition, its evaluation occurs later in life, and heritability coefficients are low. Aims The aim of this study was to identify the effects of both age at first calving and accumulated 305-day milk yield in the first lactation on length of productive life in Holstein cows. Methods Official dairy control data of 31 562 Holstein cows, calved from 2010 to 2014, in 321 herds from Paraná state, Brazil, were analysed by using the Kaplan–Meier estimator and Cox regression model. Key results First calving at <21 months was associated with shortest productive life (1197.01 ± 232.40 days), whereas first calving at 24 months was associated with the lowest hazard ratio (0.572), suggesting that this is the most suitable age of first calving for a longer productive life. Low-yielding cows (first lactation yield <6392 kg) had the second lowest survival probability (47.20%), the shortest productive life (1150.60 ± 234.51 days) and the highest voluntary hazard ratio (1.30) and were prematurely culled from the herds. High-yielding cows (first lactation yield >12 024 kg) had lower culling risk at the first lactation. Conclusions Cows that started their reproductive life ∼16 months of age (first calving at 24 months) had the longest productive life and an average first lactation milk yield ∼9000 kg. Implications Reproductive management practices could affect length of productive life through effects on age at first calving and first lactation milk yield. Most of the Holstein semen used in Brazil comes from countries where longevity has already been included in selection indexes; thus, early identification of cow longevity could be used for culling decisions.

Bovine viral diarrhea virus subgenotype 1a in a mummified fetus from a Brazilian dairy cattle herd

We describe the molecular analysis of a wild-type field strain of bovine viral diarrhea virus (BVDV) identified in a mummified fetus from a small Brazilian dairy cattle herd. Nucleic acids extracted from samples of the lung, liver, heart, spleen, and kidney were tested by PCR assays for bovine alphaherpesvirus 1, Neospora caninum, Leptospira spp., Histophilus somni, and Brucella abortus, a nested PCR assay for Mycoplasma bovigenitalium and Ureaplasma diversum, and a RT-PCR assay for BVDV. Amplicons were only obtained in the RT-PCR assay for the partial amplification of the BVDV 5'UTR (288 bp) in kidney and spleen samples and the Npro (438 bp) gene in the kidney sample. Nucleotide sequencing of the amplified products and phylogenetic analyses based on the 2 BVDV genomic regions enabled the BVDV strain to be classified as subgenotype 1a.

Resistência de Rhipicephalus (Boophilus) microplus (Canestrini, 1888) aos acaricidas utilizados em gado leiteiro de Teixeirópolis, Rondônia, Brazil

Rhipicephalus microplus is one of the main ectoparasites of dairy cattle in Brazil, whose control is mainly based on the use of chemicals. However, the low variety of chemicals available, coupled with the indiscriminate use of these substances, has led to increased resistance for this tick. The objective of this study was to evaluate the resistance profile of the tick Rhipicephalus microplus to different acaricidal products used on dairy cows in Teixeiropolis-RO, using the Adult Immersion Test (TIA) or biocarrapaticidogram. Data was collected from nine farms by performing nine in vitro evaluation tests on engorged R. microplus females, using six different tick repelling treatments available on the market. Replicates of each treatment with 20 teleogins were performed for each treatment and a control group in distilled water was used for positive and negative controls. The efficiency amplitudes of each group and the average effectiveness of the acaricidal compounds were evaluated and compared by the Kruskal-Wallis test with a significance level of 95%. Statistical analyses were performed in the Action Stat statistical program. The tick repellents tested presented the following effectiveness averages: 100% (Chlorpyrifos at 50% + Cypermethrin at 6%); 99.99% (15% Cypermethrin + Chlorpyrifos at 25% + Citronellal at 1%); 77.63% (Cypermethrin at 20% + Chlorpyrifos at 50%); 100% (15% Cypermethrin + Chlorpyrifos at 25% + Piperonyl butoxide at 1%) -; 21.68% (Amitraz to 12.5%) -; 42.17% (Deltamethrin at 5%). Products with combinations of active ingredients were the most effective, and thus considered the best alternative for tick control.

A survey of whole-plant corn silages from Minas Gerais dairy farms

Whole-plant corn silage (WPCS) is a commonly used forage for feeding dairy cattle in Brazil. The aim of this study was to evaluate on-farm ensilaging practices and the nutritional value, microbiology and fermentation profiles of WPCS from dairy farms in the south of the state of Minas Gerais, Brazil. Silages from 54 dairy farms located in nine cities were sampled and a questionnaire was distributed for completion to describe the herd profile and ensilage practices. Herd size ranged from 8 to 1,000 lactating cows, and 52 % of the farms had fewer than 50 cows in lactation. The majority of the farms cultivated hard endosperm texture hybrids (52 %) and used pull-type forage harvesters (87 %). Double-sided plastic was the most used form of silo sealing (56 %) and 28 % used inoculants. Lactic acid bacteria count was greater than 6.01 log CFU g–1 in 60 % of the samples, and the mean populations of enterobacteria and Bacillus spp. were 4.23 and 4.09 log CFU g–1, respectively. Silo size ranged from 100 to 250 m3 in 44 % of the farms, and the silage removal rate was below 15 cm of the face/d in 41 % of cases. Silage dry matter (DM) concentration was 33 ± 3 % of fresh matter, NDF concentration was 57 ± 7 % of the DM, and in vitro NDF digestibility was 35 ± 11 % of the NDF. Silages with high DM concentrations had large particle size, affecting the nutritional value and the fermentative pattern. Improvements in ensiling practices can potentially inhibit the growth of spoilage microorganisms and raise the nutritional value of silages.

Evolution of fixed-time AI in dairy cattle in Brazil.

Various programs have been used to synchronize ovulation of a fertile oocyte, accompanied by fixed-time artificial insemination (FTAI). These programs involve a series of hormonal treatments to achieve four physiologic outcomes: 1) synchronize an ovarian follicular wave; 2) optimize conditions for ovulatory follicle development; 3) synchronize corpus luteum (CL) regression; and 4) synchronize ovulation. This manuscript summarizes studies conducted in Brazil with lactating dairy cows that aimed to increase pregnancy rates to E2/P4-based programs.

Phylogenetic analysis of VP1 and RdRP genes of Brazilian aichivirus B strains involved in a diarrhea outbreak in dairy calves.

Aichivirus B has been reported worldwide in calves and adult cattle with and without diarrhea. The aim of this study was to describe the molecular characteristics of the RdRP and VP1 genes of aichivirus B strains identified as the most frequent etiologic agent in a neonatal diarrhea outbreak in a high-production Brazilian dairy cattle herd. Preliminary laboratory analysis ruled out important enteropathogens (Cryptosporidium spp; Eimeria spp., E. coli F5, and bovine coronavirus). Fecal samples from diarrheic (n = 24) and asymptomatic (n = 5) calves up to 30 days old were collected for virological analysis. RT-PCR assays were performed for the detection of aichivirus B RdRP and VP1 genes and for rotavirus A VP7 and VP4 genes in fecal samples. Asymptomatic calves (control group) were negative for both viruses. Aichivirus B and rotavirus A G10P[11] genotypes were found in 54.2% (13/24) and 25% (6/24) of the diarrheic fecal samples, respectively. Aichivirus B was only identified (83.3%, 10/12) in calves up to two weeks old. Phylogenetic analysis based on the RdRP gene grouped the Brazilian strains in a new branch within the aichivirus B group. Comparative analysis of the nucleotide sequence of the VP1 gene of Brazilian and Chinese aichivirus B strains allowed the strains identified in this study to be classified in the putative lineage 1. This is the first description of a high rate of aichivirus B detection in a diarrhea outbreak in dairy calves, and the first phylogenetic study of the VP1 gene of aichivirus B wild-type strains performed in South America.

In vitro antimicrobial susceptibility and genetic resistance determinants of Streptococcus agalactiae isolated from mastitic cows in Brazilian dairy herds

Streptococcus agalactiae is one of the main causative agents of bovine mastitis and is associated with several economic losses for producers. Few studies have evaluated antimicrobial susceptibility and the prevalence of genetic resistance determinants among isolates of this bacterium from Brazilian dairy cattle. This work aimed to evaluate the frequency of the antimicrobial resistance genes ermA, ermB, mefA, tetO, tetM, aphA3, and aad-6, and in vitro susceptibility to the antimicrobials amikacin, erythromycin, clindamycin, tetracycline, gentamicin, penicillin, ceftiofur, and cefalotin, and the associations between resistance genotypes and phenotypes among 118 S. agalactiae isolates obtained from mastitic cows in Brazilian dairy herds. Of the resistance genes examined, ermB was found in 19 isolates (16.1%), tetO in 23 (19.5%), and tetM in 24 (20.3%). The genes ermA, mefA, aphA3, and aad-6 were not identified. There was an association between the presence of genes ermB, tetM, and tetO and phenotypic resistance to erythromycin, clindamycin, and tetracycline. Rates of resistance to the tested antibiotics varied, as follows: erythromycin (19.5%), tetracycline (35.6%), gentamicin (9.3%), clindamycin (20.3%), penicillin (3.4%), and amikacin (38.1%); conversely, all isolates were susceptible to ceftiofur and cefalotin. Antimicrobial resistance testing facilitates the treatment decision process, allowing the most judicious choice of antibiotics. Moreover, it enables regional and temporal monitoring of the resistance dynamics of this pathogen of high importance to human and animal health.

In vitro antimicrobial susceptibility and genetic resistance determinants of Streptococcus agalactiae isolated from mastitic cows in Brazilian dairy herds

Streptococcus agalactiae is one of the main causative agents of bovine mastitis and is associated with several economic losses for producers. Few studies have evaluated antimicrobial susceptibility and the prevalence of genetic resistance determinants among isolates of this bacterium from Brazilian dairy cattle. This work aimed to evaluate the frequency of the antimicrobial resistance genes ermA, ermB, mefA, tetO, tetM, aphA3, and aad-6, and in vitro susceptibility to the antimicrobials amikacin, erythromycin, clindamycin, tetracycline, gentamicin, penicillin, ceftiofur, and cefalotin, and the associations between resistance genotypes and phenotypes among 118 S. agalactiae isolates obtained from mastitic cows in Brazilian dairy herds. Of the resistance genes examined, ermB was found in 19 isolates (16.1%), tetO in 23 (19.5%), and tetM in 24 (20.3%). The genes ermA, mefA, aphA3, and aad-6 were not identified. There was an association between the presence of genes ermB, tetM, and tetO and phenotypic resistance to erythromycin, clindamycin, and tetracycline. Rates of resistance to the tested antibiotics varied, as follows: erythromycin (19.5%), tetracycline (35.6%), gentamicin (9.3%), clindamycin (20.3%), penicillin (3.4%), and amikacin (38.1%); conversely, all isolates were susceptible to ceftiofur and cefalotin. Antimicrobial resistance testing facilitates the treatment decision process, allowing the most judicious choice of antibiotics. Moreover, it enables regional and temporal monitoring of the resistance dynamics of this pathogen of high importance to human and animal health.

Dairy production practices and associated risks for bovine vaccinia exposure in cattle, Brazil.

A cross-sectional serosurvey was performed to identify environmental features or practices of dairy farms associated with risk for exposure to vaccinia-like viruses in dairy cattle in Brazil. Sera from 103 cows from 18 farms in Minas Gerais state were examined for Orthopoxvirus-neutralizing antibodies. A database of 243 binary or multiple-selection categorical variables regarding the physical features and surrounding ecology of each property was obtained. Thirteen of 46 presumptive predictor variables were found to be significantly associated with Orthopoxvirus serostatus by univariate logistic regression methods. Use of teat sanitizer and having felids on the property were independently associated with virus exposure by multivariable analysis. Rodents have long been suspected of serving as maintenance reservoirs for vaccinia-like viruses in Brazil. Therefore, domestic felids are not only effective predators of small rodent pests, but also their urine can serve as a deterrent to rodent habitation in buildings such as stables and barns. These results corroborate previous evidence of the high significance of rodents in the Vaccinia virus transmission cycle, and they also raise questions regarding the common use of teat sanitizers in dairy production areas.

MASTITE BOVINA: UMA REVISÃO

The mastite, inflammation process of mammary gland, characterized by a decrease in production and changes in milk composition, is considered the disease of major impact for dairy cattle in Brazil. Normally, this disease is resultant of the action of infectious agents, and may be involved different species of virus, fungi, and mainly, bacteria. It is important to remember, that the mastite, of any form and effect, reduces milk production and, in severe cases, may occur loss of one or more teats. Thus, the control of bovine mastite is important for the milk production of high quality. The aim of study is develop a study about this pathology that affects the dairy cattle and their effects in production and quality milk, and consequently, farmers, dairy industry and their products.

Neospora caninum: Seroprevalence in beef cattle in the mountainous region of Santa Catarina, Brazil

The distribution of Neospora caninum, an important agent of reproductive disorders in cattle, has been frequently reported in dairy cattle in Brazil and worldwide. Records of infection are less frequent in beef cattle. To determine the seroprevalence of bovine neosporosis, 507 beef cattle blood samples were collected from January 2013 to September 2015, from 16 municipalities of the Associação dos Municípios da Região Serrana (AMURES). Samples were tested for the presence of IgG antibodies ( ? 1:100) against N. caninum by indirect immunofluorescence antibody test (IFAT). Information about sex, age, and origin of the bovines were obtained from the Brazilian Bovine and Bubaline Identification and Certification System (SISBOV), and were tabulated for statistical analysis (Chi-square and Fisher Exact test, P ? 0.05). Of the 507 serum samples analyzed, 70 (13.81%) contained antibodies against N. caninum with titers of 1:100 (16), 1:200 (22), 1:400 (17), 1:800 (nine), 1:1600 (four) and 1:3200 (two). Positive specimens were collected from 13 of the 16 municipalities and across all age groups. Of the positive samples, there were no statistical differences between males and females (32.86% vs. 67.14%, P= 0.1072), age groups (P= 0.4116), or municipalities (P= 0.6838). While not statistically significant (P>0.05), higher seroprevalence was observed among older females. Although seroprevalence was relatively low, results indicate that infection by N. caninum in beef cattle is widespread in the studied region.

Use of yeast (Saccharomyces cerevisiae) at the diet of lactating cows

The dairy cattle in Brazil is an activity of economic and social importance, both for food and nature in the generation of income and jobs. Increased efficiency in milk production is related to the improvement of power. Thus, food additives, are used to improve animal performance, operating in controlling or modifying the rumen fermentation pattern, thereby preventing disturbances metabólicos.O microorganisms of interest in the use as feed additives for dairy cows has increased significantly in recent years. A group commonly used are yeasts, particularly Saccharomyces cerevisiae, identified as probably responsible for improvement in the rumen, with no effect on pH. So it was aimed to observe the influence of the use of yeast (Saccharomyces cerevisiae) in diets of lactating cows on the increased production of leite.Os data used in this study were derived from the Quilombo Farm, owned by Winston Frederick Adams Drumond. The property is located on Highway MG-154, 7 km in the city of Capinópolis, Minas Gerais. Cows were selected in Gyr cattle by the head coach of PO propriedade.Com order to increase the production of milk was added to the diet in the rumen specific live yeast Saccharomyces cerevisiae CNCM I-1077 (Levucell SC Farm of Lallemand, pack of 5 kg ), with inclusion of 50 g / animal / day, divided between the five day feeding schedule, 10 grams each. Showed an increase in milk production of animals supplemented with the yeast Saccharomyces cerevisiae.

Genetic trend estimates for milk yield production and fertility traits of the Girolando cattle in Brazil

Annual genetic trends and selection differentials for 305-day milk yield (305MY), age at first calving (AFC), and first calving interval (FCI) were estimated by four selection paths [sires of bulls (SB), dams of bulls (DB), sires of cows (SC), and dams of cows (DC)] for Girolando dairy cattle in Brazil. A total of 12,739 lactation records were obtained from the Brazilian Girolando Breeders Association with cows calving in the period from 2000 to 2011. Two periods were involved: the first, from 1979 to 1996, corresponding to the formation and expansion of the herd, and second, from 1997 to 2007, characterized by the implementation of the breeding program of the Girolando breed. The whole period from 1979 to 2007 was also considered. The Wombat program was used to fit an animal model for the analyses. Estimated breeding values were extracted to calculate genetic trends for the four selection paths. Greater significant estimates of annual genetic changes for 305MY were obtained for the SC and SB paths, being both during the second period. The greatest annual genetic change estimates for 305MY were 43.06 and 101.97milk/yr for SC and DB, respectively, during the second period. A favorable genetic response was found for the SB and SC paths for AFC, averaging −4.24 (second period) and −0.32day/yr, respectively. For FCI, this effect was from 0.04 to 0.18 range for all paths. When all selection paths were combined, estimated annual genetic changes for 305MY and AFC were 7.40milk/yr and −0.13day/yr. Therefore, the results of this study showed that a well-designed genetic program has a positive impact on 305MY and AFC and a little or without impact on FCI in Girolando cattle over a 28-yr period.