RESUMO
Staphylococcus aureus is a common causative agent of bovine mastitis in dairy herds worldwide. This study was designed to assess the prevalence of mastitis in cows through screening tests and molecular characterization of Staphylococcus aureus strains. Out of 175 randomly screened cows, mastitis was detected in 50 cows by California Mastitis Test (CMT), and from those mastitic cows, 200 quarter milk samples were collected for subsequent culture and PCR based identification. The herd, cow and quarter level prevalence of mastitis was 73.3, 28.6 and 29.5% respectively, and subclinical mastitis (SCM) was the predominant type in all cases. According to bacteriology the overall prevalence of herd, cow and quarter level Staphylococcus aureus mastitis was 72.7, 74.0 and 62.0%, respectively, and the pathogen was mostly associated with clinical mastitis (CM). Cows breed, parity, daily milk yield, regular teat dipping, and dry cow therapy were significantly associated (Pâ¯<â¯0.05) risk factors for mastitis onset. This study identifies 145 Staphylococcus aureus isolates which varied greatly with the categories of mastitis (higher in CM), udder quarter location (highest in right rear quarters), and to a lesser extent in the study areas (Pâ¯<â¯0.05). Antimicrobial susceptibility testing revealed that 79.3% Staphylococcus aureus strains were resistant to at least one antimicrobial, 49.0% to two or more antimicrobials, and clinical isolates showed more resistance to all tested antibiotics. The highest resistance rate was found to oxytetracyclin, and no resistance to ceftriaxone and azithromycin. Seven enterotoxin gene profile were detected in the tested isolates, and mecA was found in 20.0% isolates indicating the emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA). The isolates were carrying genes in combination, and were found higher in SCM cases. In this study, plasmids (>23â¯kb to 2.9â¯kb) were detected in 70.3% strains, and 54.9% plasmid bearing strains were multiple drug resistant (MDR). Thus, the high prevalence of Staphylococcus aureus mastitis is an important concern for diary industry of Bangladesh since the strains of this pathogen is becoming more resistant to commercially available antimicrobials, and this is an alarming concern for both animal and public health.
RESUMO
Administration of vitamin, mineral and antimicrobials at the end of lactation plays potential role in preventing mastitis in dairy cows. A total of 255 cows dividing into five groups (A = 50, B = 50, C = 50, D = 50 and E = 55) at their late gestation period were selected to explore the effect of vitamin E, selenium and antimicrobial therapy on mastitis incidence, their productive and reproductive performances. Each cow of group A received α-tocopherol + sodium selenite orally daily for last 30 days before calving, while each cow of group B, C and D was treated with α-tocopherol + sodium selenite intramuscular injection, procaine penicillin + neomycin sulfate, and dicloxacillin sodium intramammary infusions at Day 30-20 before calving, respectively. Group E cows served as untreated control. California mastitis test (CMT) revealed that 70.0%, 76.0%, 84.0% and 100.0% cows in group A, B, C and D, respectively were free from new intramammary infections (IMIs) during early lactation period. The bacteriological results showed highest IMIs rates (76.3%) in group E and lowest IMIs (2.0%) in group D (P < 0.05). Staphylococcus aureus and Escherichia coli were the most predominant udder pathogens in all groups except group D (only CNS). The mean IMIs incidence (20.5%) was significantly lower in treated cows (P < 0.001). The treated cows had higher cure rates (81.9%) than control cows (23.1%) and overall efficacy of treatments on cure rates was 71.8% for all mastitis pathogens (P < 0.0001). The productive and reproductive performances of the treated cows at postpartum and early lactation period remained always higher than their non-treated counterparts (P < 0.001). A number of cow and herd related factors were identified to be significantly associated with mastitis (P < 0.001). The results concluded that antimicrobial therapy had more beneficial effect in preventing mastitis over vitamin-mineral administration and intramammary infusion with dicloxacillin sodium remained as the best effective preventive strategies for mastitis in dairy cows.
RESUMO
The objective was to evaluate the effect of the interval between ovarian hyperstimulation and laparoscopic ovum pick-up (LOPU) on quality and developmental competence of goat oocytes before and after in vitro maturation (IVM) and intracytoplasmic sperm injection (ICSI). Estrus was synchronized with an intravaginal insert containing 0.3g progesterone (CIDR) for 10d, combined with a luteolytic treatment of 125 microg cloprostenol 36 h prior to CIDR removal. Ovaries were hyperstimulated with 70 mg FSH and 500 IU hCG given im 36, 60, or 72 h prior to LOPU (n=15, 16, and 7 does, respectively). For these groups, oocyte retrieval rates (mean+/-S.E.M.) were 24.7+/-2.9, 54.5+/-4.7, and 82.8+/-4.6% (P<0.001), and the proportions of cumulus-oocyte complexes (COC) with more than five layers of cumulus cells were 29.7+/-8.3, 37.6+/-6.9, and 37.3+/-7.0% (P<0.001). The proportion of IVM oocytes was highest at 72 h (82.1+/-2.8%; P<0.05), with no significant difference between 36 and 60 h (57.3+/-8.9% and 69.0+/-8.4%). Cleavage rates of ICSI embryos were 4.2+/-4.2, 70.9+/-8.4, and 78.9+/-8.2% with LOPU 36, 60, and 72 h post FSH/hCG (P<0.01), with a lower proportion of Grade-A embryos (P<0.05) following LOPU at 36 h compared to 60 and 72 h (29.7+/-8.3%, 37.6+/-6.9%, and 37.3+/-7.0%). In summary, a prolonged interval from FSH/hCG to LOPU improved oocyte retrieval rate and oocyte quality. Therefore, under the present conditions, LOPU 60 or 72 h after FSH/hCG optimized yields of good-quality oocytes for IVM and embryo production in goats.
