Acid-base balance is one of the most vigorously regulated variables of the body, including genital organs. Subacute ruminal acidosis is a common disturbance in dairy cows that disturbs several biochemical indices in the blood, cerebrospinal fluid, and urine. The possible negative effects of metabolic acidosis on the follicular fluid (FF) composition and, subsequently, on oocyte quality, are not fully elucidated. This study aimed to evaluate the changes in acid-base balance (ABB) in FF and blood during acute metabolic acidosis in dairy heifers. Ten Holstein heifers were stimulated with FSH in eight decreasing doses at 12-hour intervals (D0-D3). Acidosis was induced by oral administration of sucrose at 9 g/kg of body weight, dissolved in 10 L of warm tap water, at D3. Samples were collected from each cow at 0, 8, 12, 16, 24, 32, 40, and 48 hours after treatment. Samples of FF, obtained by transvaginal follicular aspiration, and peripheral blood were examined for ABB parameters: pH, pCO2, pO2, HCO3-, and base excess (BE). A significant decrease in pH, HCO3-, and BE values in the blood, as well as FF, occurred after sucrose treatment. The lowest pH values occurred in blood at 16 hours, and in FF at 24 hours, after treatment (7.30 ± 0.05 and 7.33 ± 0.05, respectively). The lowest HCO3- values in blood (18.75 ± 3.2 mmol/L) and FF (18.07 ± 2.84 mmol/L) occurred 24 hours after treatment, as did the lowest BE values (-6.61 ± 3.7 mmol/L and -7.53 ± 3.89 mmol/L, in blood and FF, respectively). Significant correlations for HCO3- (r = 0.928), BE (r = 0.946), pH (r = 0.889), and pCO2 (r = 0.522) existed between blood and FF samples. The results demonstrated that metabolic acute acidosis substantially influences the characteristics of both serum and FF.

The aim of this study was to evaluate the effect of intrafollicular treatment (IFT) with different doses of luteinising hormone. Experimental heifers were treated with a single deslorelin implant to desensitise gonadotroph cells of the pituitary gland. Thereafter, follicular development was stimulated by exogenous FSH treatment. Intrafollicular treatment with 10, 5, 1 and 0.01 µg LH was performed on one single follicle while other follicles remained untreated. Human chorionic gonadotrophine (2000 UI) was administered intravenously as a control. Ovulation and development of the corpus luteum occurred after all intrafollicular treatments with 10 and 5 µg LH. After IFT using 1 µg of LH 75% animals (3/4) ovulated. The dose of 0.01 µg was not followed by any ovulation whereas control treatments with hCG were followed by an ovulation of the majority of follicles present in the ovaries. In conclusion, IFT with different doses of LH (greater than 0.01 µg) is capable of inducing ovulation.

The aim of this study was to evaluate a new device for the ultrasound-guided transvaginal aspiration of follicular fluid for acid-base balance analysis (ABB set) in comparison with the original modified commercial OPU set. In the ABB set, an aspiration syringe was placed in the front part of the new tool's handle, next to the transducer, so as to enable direct collection of the sample into the syringe. To obtain a sufficient amount of testable fluid, reservoirs of urine (rubber balloons) were used for later aspiration under laboratory conditions in Experiment 1. Fifteen triads of samples (each triad with two punctures) were collected. While the first sample of each triad was taken using the ABB set (ABB sample), two samples were taken by one puncture using the original modified commercial OPU set: aerobic phase of sampling (AE sample) with air present in the tubing at the start of sampling and the subsequent anaerobic phase of sampling (AN sample). Values determined in the second sample from the triad (AE) varied from the values in both ABB and AN samples (pH 7.685 vs. 7.704 vs. 7.692, pCO2 11.13 vs. 10.3 vs. 10.85, pO2 6.87 vs. 8.67 vs. 7.02). In Experiment 2, ultrasound-guided transvaginal aspirations were carried out in 13 cows bearing ovarian cysts with diameters of at least 3 cm, using plastic aspiration syringes (Experiment 2P) and in 12 cows using glass aspiration syringes (Experiment 2G). The sequence of samples was the same as in Experiment 1. We found a significantly higher pH in AE in comparison to AN (7.357 vs. 7.348), lower pCO2 (6.85) and higher O2 (14.12) in samples of AE in comparison to samples of ABB and AN (pCO2 7.36, 7.30; O2 9.95, 10.63 respectively) in cystic fluid in Experiment 2P. We found a significantly higher pH (7.4), lower pCO2 (5.98) and a higher pO2 (12.35) in AE samples in comparison to ABB and AN samples of cystic fluid (pH 7.386, 7.385; pCO2 6.39, 6.35 and O2 10.56, 10.65, respectively) from Experiment 2G. We conclude that the acid-base balance assay was affected by air, present in the tubing during aerobic sampling in comparison to anaerobic and ABB set sampling. These pre-analytical changes can be prevented by the use of the ABB set because the results obtained with the ABB set were not different from that of the AN samples. We also confirmed pre-analytical changes in acid-base balance parameters in the cystic fluid after it had been stored in plastic aspiration syringes. Our new ABB set equipped with a glass aspiration syringe is suitable for sampling follicular fluid for both acid-base balance and gas analysis.

The aim of this study was to evaluate a new double-channel system for ultrasound-guided transvaginal intrafollicular treatment in cattle. The system is equipped with separate aspiration and treatment channels facilitating the aspiration of a small part of follicular fluid followed by the immediate injection of the same amount of treatment solution. In Experiment 1 an intracystic injection was performed successfully in all cows (6/6). In Experiment 2 saline was administered to dominant follicles with an overall success rate of 87.5% (14/16). This new double-channel system represents a reliable method for intrafollicular treatment preceded by an aspiration of the necessary amount of follicular fluid without an increase in intrafollicular pressure.