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The objectives of this study were to examine the influence of body condition of cows on metabolic and antioxidative status, as well as to investigate the relationship between metabolic indicators of lipid mobilization and oxidative stress during transition period. The study was conducted on 24 Holstein-Friesian dairy cows divided into 2 groups according to their body condition score (BCS) as optimal (n = 12; BCS from 3.25 to 3.75) or adipose (n = 12; BCS ≥4). Metabolic status (glucose, triglycerides, total cholesterol, HDL cholesterol, NEFA and BHB), paraoxonase-1 (PON1) and apolipoprotein A-I (ApoA-I) were analysed in sera taken on days -30, -10, -2, 0, 5, 12, 19, 26 and 60 relative to parturition. Adipose cows had significantly higher glucose concentration at parturition being significantly decreased after parturition on days 12 and 19. Total cholesterol and HDL-C concentrations were the lowest at parturition and significantly higher on days 26 and 60 after parturition in both groups of cows. Both investigated groups had significantly higher NEFA concentration from parturition until day 19 after parturition, indicating energy deficit and an increased lipid mobilization after calving. There were no significant differences in BHB concentration during transition period in both groups. No significant differences were found in PON1 activity and ApoA-I concentration during transition period in both groups of cows. However, in adipose cows, although not significantly different, PON1 was decreased from calving until day 19 after parturition indicating a disturbance in antioxidative status in adipose cows. PON1 significantly positively correlated with total cholesterol and HDL-C concentrations and negatively with NEFA indicating a strong relationship of PON1 with lipid metabolism. Significant positive correlation between NEFA and BHB in both groups of cows points out on energy deficit during transition period that cows tend to overcome by lipid mobilization providing alternative source of energy needed for parturition and lactation., (© 2015 Blackwell Verlag GmbH.)

It has been suggested that the time of insemination has effect on the calves' sex ratio because of the differences in timing of capacitation, motility and survival time of the X and Y spermatozoa in the female reproductive tract. We have conducted a field trial to study the effects of different semen deposition sites on the sex ratio and fertility in cattle. Two groups of 450 cows were inseminated via artificial insemination: group A was inseminated into the uterine body and group B was inseminated deep into the uterine horn ipsilateral to the ovary with dominant follicle. After applying several exclusion criteria, a total of 607 pregnant cows were considered for data analysis (group A = 318 and group B = 289 cows). The conception rate was 7% higher (p < 0.05) in the group A, with 23% more of the male calf pregnancies (p < 0.001). At the same time, 18% more of the female calves were calved in the group B (p < 0.005). The difference in male calves between the two groups was 21% and in female calves was 20% (p < 0.001). We conclude that semen deposition site plays a significant role in differences in gender ratio observed after calving. Intracornual semen deposition resulted in a higher ratio of female calves, whereas uterine body deposition site resulted in higher male calves ratio, probably contributing physiologically to the differences in motility, capacitation time, the lifespan of X vs Y spermatozoa and to the pronounced shift of X spermatozoa in the female genital tract., (© 2010 Blackwell Verlag GmbH.)