IntroductionThe purpose of the current study was to evaluate the blood glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) levels under seasonal variations in dairy cows during transition period, and to assess the relationship between chosen reproductive parameters, GSH-Px, and MDA.Material and MethodsHolstein cows calving in January were assigned into winter group (n = 42), while cows calving in August were assigned into summer group (n = 42). Blood samples were collected from the jugular vein 21, 14, and 7 days before calving, at calving (0 day), and 7, 14, and 21 days after calving. Reproductive parameters obtained from farm records were evaluated.ResultsIn both groups of cows, GSH-Px activity decreased from 21 days before calving to day 0, and it gradually continued to increase until 21 days after calving. GSH-Px activity was higher in winter group compared to summer group during the transition period (P < 0.05). MDA levels in both groups increased over time starting from 21 days before calving to 0 day, but it gradually decreased thereafter. MDA levels were higher in summer group compared to winter group during the transition periods (P < 0.05). Summer group of cows showed higher intervals of calving-to-oestrus, calving-to-conception, and higher insemination index (P < 0.01). Negative correlation was recorded between GSH-Px and MDA during all examination days (P < 0.01). MDA levels correlated with calving to conception interval on day 21 before calving and day 0 (P < 0.01) and insemination index on day 0 and 21 days after calving (P < 0.01). GSH-Px activity was negatively correlated with calving to conception interval on day 21 before calving, day 0, and 21 days (P < 0.01) after calving. Negative correlation on day 21 before calving and day 0 was also determined between GSH-Px and insemination index (P < 0.01).ConclusionThis study showed that blood oxidant and antioxidant levels have affected the fertility parameters in cows under seasonal variations.

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Introduction The objectives of this study were to determine the role of a fall in pre-calving body condition score (BCS) in postpartum metabolic status and reproductive outcomes, and gauge the indicativeness of blood metabolites during the transition period. Material and Methods Cows were grouped based on BCS loss between days −14 ±3 and 0 relative to calving. Cows that lost no BCS were the BCS control group (BCS-C), cows that lost 0.25 BCS points the low BCS loss group (BCS-L), and those that lost 0.5 points or more the high BCS loss (BCS-H) group. Blood was taken on days −14 ±3, 3, 14, and 30 ±4 for determination of comprehensive metabolic panel biomarker levels. Beta-hydroxybutyric acid (BHBA) levels were quantified on postpartum examination days. Vaginal discharge scores, ovarian activity on day 30 ±4, and subsequent fertility parameters were evaluated. Results The BCS-H cows had lower mean Ca concentrations before calving and on day 3, when the group’s BHBA and CK were higher (P < 0.05); on day 14 they had higher AST concentrations (P < 0.05). The BCS-L cows had greater bilirubin levels (P < 0.05). The BCS-H cows had lower cyclicity and higher endometritis rates. First service pregnancy rates were 50%, 50%, and 61.9%, open days 96.8, 95.75, and 89.2, and overall pregnancy rates 56.25%, 65%, and 80.95 % in the BCS-H, BCS-L, and BCS-C groups, respectively. Conclusion Prepartum BCS loss of ≥ 0.5 points could be associated with Brown Swiss cow low Ca and BHBA concentrations early postpartum, and with subsequent uterine health and overall pregnancy rate. Prepartum Ca concentration might be a prognostic biomarker for postpartum metabolic status and reproductive outcomes.

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The goal of this study was to investigate pathogen types found in milk samples from cows with clinical mastitis, as well as the sensitivity of isolated bacteria to different antibiotics. The study was carried out on 103 milk samples collected from dairy cows with clinical mastitis. Microbiological isolation and identification were performed to identify gram negative and gram positive bacteria, Mycoplasma bovis and fungi. Then, bacteria isolated from infected milks were subjected to antibiogram, using 27 antimicrobials agents. As a result, a total of 146 isolates were obtained from 103 milk samples. The predominant pathogen isolates recovered were fungi (21.9%), Escherichia coli (19.9%) and Staphylococcus aureus (13.7%), followed by Mycoplasma bovis (8.2%) and Streptococcus uberis (6.8%). The mixed predominant pathogen was fungi, (75%) the majority of which mixed with gram positive bacteria. Ampicillin, Imipenem, Chloramphenicol and Streptomycin were the least effective antimicrobial agents, while the most effective agents were Florfenicol, followed by Amikacin and Kanamycin / Cefalexin. In conclusion, the types of microorganisms that cause mastitis and the antibiogram results of the bacteria isolated varied. Above all, fungal mastitis is a severe problem that should always be considered prior to starting antibiotic treatment.