Molecular characterization and clonal diversity of methicillin-susceptible Staphylococcus aureus in milk of cows with mastitis in Brazil

Mastitis is an important disease for the dairy industry worldwide, causing economic losses and reducing milk quality and production. Staphylococcus aureus is a worldwide agent of this intramammary infection, which also causes foodborne diseases. The objective of this study was to determine the frequency of methicillin-susceptible Staphylococcus aureus (MSSA) isolates in milk of mastitis cows in Brazil and to analyze the genetic lineages and the content of antimicrobial resistance genes and virulence factors among these isolates. Fifty-six MSSA isolates were recovered from 1,484 milk samples (positive for the California mastitis test) of 518 cows from 11 different farms in Brazil (representing 51% of total Staph. aureus obtained), and they were further characterized. Methicillin-susceptible Staphylococcus aureus were isolated from 3.7% of California mastitis test-positive tested milk samples and from 6.2% of tested mastitic cows. Methicillin-susceptible Staphylococcus aureus isolates were characterized by spa typing, agr typing, and multilocus sequence typing, and resistance and virulence traits were investigated by PCR. Seven spa types were identified among MSSA (% of isolates): t127 (44.6), t605 (37.5), t002, t1784, t2066 (1.8), and 2 new ones: t10856 (10.7) and t10852 (1.8). Five distinct sequence types (ST) were detected (% of isolates): ST1 (46.4), ST126 (37.5), ST133 (10.7), ST5 (3.6), and a novel ST registered as ST2493 (1.8). Resistances were detected for streptomycin, chloramphenicol, and tetracycline. One strain contained the chloramphenicol resistance gene (fexA; included within transposon Tn558) and 3 strains contained the tetracycline resistance gene [tet(K)]. Methicillin-susceptible Staphylococcus aureus strains were susceptible to most of the antibiotics studied and lacked the virulence genes of Panton-Valentine leukocidin (lukF/S-PV), toxic shock syndrome toxin 1 (tst), exfoliative toxin A (eta), and exfoliative toxin B (etb), as well as the genes of the immune evasion cluster. Methicillin-susceptible Staphylococcus aureus isolates were detected in a relatively low proportion of cows with mastitis (6.2%) and recovered isolates presented high diversity of genetic lineages, with CC1 and CC126 the predominant clonal complexes, and CC133 also being detected. Larger epidemiological studies with molecular characterization of isolates are required to deepen the knowledge on the circulating genetic lineages among the cow population with mastitis. © 2013 American Dairy Science Association.

Qualidade nutricional dos queijos mussarela orgânico e convencional elaborados com leite de búfala e de vaca

Pós-graduação em Alimentos e Nutrição - FCFAR

Efeitos genéticos e ambientais da habilidade de permanência de búflas leiteiras da raça Murrah no rebanho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hemograma, perfil bioquímico e proiteínas de fase aguda em bovinos e bubalinos submetidos a laparotomia exploratória, tratados ou não com fenilbutazona

Pós-graduação em Cirurgia Veterinária - FCAV

Contagem de células somáticas no leite de búfalas e sua aplicação na seleção para resistência à mastite

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

NaOCl effect on biofilm produced by Staphylococcus aureus isolated from the milking environment and mastitis infected cows

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of parity on concentrations of enzymes, proteins, and minerals in the milk of cows

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of calcium salts of soybean oil on factors that influence pregnancy establishment in Bos indicus beef cows

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Glucose, Cholesterol, Total Protein and Growth Factor Insulin-like Type I in Follicular Fluid of River Buffaloes (Bubalus bubalis)

In order to establish the concentrations of glucose, cholesterol, total protein and growth factor insulin-like type I (IGF-I) in the follicular fluid, 26 Murrah breed river buffaloes, between 45 and 70 days postpartum, empty, multiparous, with average live weight of 675 +/- 56 kg and average body condition of 3.5 points on a scale of 1-5, were used in this study. The fluid was collected from dominant follicles with diameters between 8 and 12 mm by OPU, and was not taken into account the stage of the estrous cycle. Using this technique, the wave of follicular development was synchronized six days prior to collection. Biochemical analysis was performed to glucose and cholesterol through the enzymatic colorimetric method using commercial kit glicose CHOLESTEROL GOD-PAP and CHOD-PAP (Kovalent), respectively. Determination of total protein was carried out by using total protein commercial kit (Kovalent) Biuret method, and the readings were performed using absorption spectrophotometry with visible light. Concentration of IGF-I was measured by Radioimmunoassay (RIA) technique using commercial IRMA Kit IGF-I (INMUNOTECH). Descriptive statistics were developed using the PROC MEANS procedure of SAS (2009). Concentration of glucose (4.0 +/- 0.75 mmol / L-1) and IGF-I (340 +/- 129.83 ng / mL (-1)) were higher than those reported by other authors in river buffaloes and cows, respectively. However, cholesterol levels (0.51 +/- 0.12 mmol / L (-1)) and total protein (58.4 +/- 4.43 g / L (-1)) behaved inferior to other studies in same species. The results indicated that there is relationship among the nutritional aspects, diameter of follicles aspirated and productive period in the concentration of biochemical indicators.

The Buffalo Genome and the Application of Genomics in Animal Management and Improvement

The publication of the human genome sequence in 2001 was a major step forward in knowledge necessary to understand the variations between individuals. For farmed species, genomic sequence information will facilitate the selection of animals optimised to live, and be productive, in particular environments. The availability of cattle genome sequence has allowed the breeding industry to take the first steps towards predicting phenotypes from genotypes by estimating a genomic breeding value (gEBV) for bulls using genome-wide DNA markers. The sequencing of the buffalo genome and creation of a panel of DNA markers has created the opportunity to apply molecular selection approaches for this species.The genomes of several buffalo of different breeds were sequenced and aligned with the bovine genome, which facilitated the identification of millions of sequence variants in the buffalo genomes. Based on frequencies of variants within and among buffalo breeds, and their distribution across the genome compared with the bovine genome, 90,000 putative single nucleotide polymorphisms (SNP) were selected to create an Axiom (R) Buffalo Genotyping Array 90K. This SNP Chip was tested in buffalo populations from Italy and Brazil and found to have at least 75% high quality and polymorphic markers in these populations. The 90K SNP chip was then used to investigate the structure of buffalo populations, and to localise the variations having a major effect on milk production.

Molecular Evaluation of Developmental Competence of Oocytes Collected In Vivo from Buffalo and Bovine Heifers during Winter and Summer

Buffaloes and bovines are polyestrous and seasonal or annual livestock, respectively, that show reduced fertility during heat stress. To investigate whether reduced fertility is related to oocyte competence in both species, immature oocytes from buffalo and bovine heifers were collected during winter and summer and subjected to molecular analyses. In each season, heifers of both species had their follicular wave emergence synchronized with a standard protocol (Ferreira et al., 2011). Before being subjected to ovum pick up (OPU), cutaneous (CT; degrees C) and rectal (RT; degrees C) temperatures and respiratory rate (RR; breaths/min) were measured. Oocytes' RNA was extracted to evaluate the expression of target genes related to mtDNA replication/transcription (PPARGC1A, TFAM and MT-CO1), apoptosis (BAX and BCL2) and HS (HSP90AA1 and HSPA1AB). ACTB, HIST1H2AG and GAPDH were initially chosen as housekeeping genes. In buffaloes, CT (35.0 +/- 0.4 vs 23.8 +/- 0.5), RT (38.7 +/- 0.1 vs 38.0 +/- 0) and RR (21.3 +/- 1.2 vs 15.4 +/- 1.1) were higher during summer than winter. However, in bovine heifers, RT (38.7 +/- 0.1 vs 38.6 +/- 0.1) and RR (44.8 +/- 1.5 vs 40.6 +/- 1.5) were similar in both seasons, while CT (31.6 +/- 0.3 vs 30.2 +/- 0.3) was increased during summer. Reduced expression of ACTB, HIST1H2AG and GAPDH was evidenced during summer, disqualifying them as housekeeping genes. Similarly, the expression of all target genes was reduced during summer in oocytes of both species. In summary, physiological responses to heat stress seem to be more intense in buffalo than bovine heifers. However, in both species, negative effects of heat stress upon oocyte quality occur at the molecular level and affects genes related to several biological functions.

Analysis of the risk factors relating to cows' resistance to Rhipicephalus microplus ticks during the peripartum

This study aimed to evaluate season, breed, number of lactations and milk production as risk factors relating to Rhipicephalus microplus infestation in dairy cows during the peripartum. Eighty-four animals were randomly selected through proportional stratified sampling. All engorged and partially engorged female R. microplus specimens measuring 4.5-8.0 mm were counted during the 5 weeks before calving, calving week and 5 weeks after calving. The peripartum had a significant effect [calving (p < 0.05; prevalence ratio (PR)= 3.12) and post calving (p < 0.05; PR = 2.02)] on R. microplus infestation. Although the average tick count was higher during the rainy season than during the dry season, there was no significant difference (p = 0.055; PR = 0.63). The average R. microplus count was significantly higher (p < 0.05; PR = 2.10) in Bos taurus animals, followed by F1 (p < 0.05; PR = 1.64) and Girolando (p < 0.05; PR = 1.39). The average R. microplus count was significantly higher (p < 0.05; PR = 0.97) in first-lactation animals, followed by those at the second, third and, fourth or subsequent lactation. Milk production showed a negative correlation with R. microplus count, such that high-production animals were significantly (p = 0.003; PR = 2.04) more vulnerable to infestation than were low-production animals. First-lactation and high-production B. taurus animals had greatest vulnerability to R. microplus infestation over the peripartum period, and constituted the at-risk group in the dairy herd.u

In vivo embryo production in cows superovulated 1 or 2 days after ovum pick-up

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inducing ovulation early postpartum influences uterine health and fertility in dairy cows

The objective of the current study was to evaluate the effect of GnRH early postpartum on induction of ovulation, uterine health, and fertility in dairy cows. Holstein cows without a corpus luteum (CL) at 17 +/- 3 DIM were assigned randomly to receive i.m. GnRH (n = 245) at 17 +/- 3 and 20 +/- 3 DIM or remain as controls (n = 245). Ovaries were scanned by ultrasonography twice weekly totaling 4 examinations. Ovulation was characterized by the appearance of a CL >= 20 mm at any ultrasound or CL <20 mm in 2 consecutive examinations. Clinical and cytological endometritis were diagnosed at 35 DIM. Compared with control, GnRH increased ovulation up to 3.5 d after the last treatment (78.7 vs. 45.0%) and did not affect the prevalence of clinical endometritis (23.9 vs. 18.6%) or cytological endometritis (30.9 vs. 32.8%). Prevalence of clinical endometritis increased in cows that had calving problems (32.6 vs. 15.9%) and metritis (40.6 vs. 15.8%). Metritis increased prevalence of cytological endometritis (50.7 vs. 23.5%). Treatment with GnRH did not affect pregnancy per artificial insemination at 32 (37.6 vs. 38.6%) or 74 d after artificial insemination (35.0 vs. 31.5%), but reduced pregnancy loss (6.8 vs. 18.1%). No overall effect of GnRH treatment on hazard of pregnancy was observed; however, an interaction between GnRH treatment and ovulation showed that GnRH-treated cows that ovulated had increased hazard of pregnancy by 300 DIM compared with GnRH-treated and control cows that did not ovulate (hazard ratio = 2.0 and 1.3, respectively), but similar to control cows that ovulated (hazard ratio = 1.1). Gonadotropin-releasing hormone early postpartiim induced ovulation without affecting uterine health, but failed to improve pregnancy per artificial insemination or time to pregnancy, although it reduced pregnancy loss.

Manipulation of the periovulatory sex steroidal milieu affects endometrial but not luteal gene expression in early diestrus Nelore cows

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)