Muhammed Furkan Ciftci

This field study evaluated the effects of 400 and 500 IU equine chorionic gonadotropin (eCG) on oestrus response, fertility, and lambing performance in Ile-de-France ewe lambs and adult ewes under seasonal-transition field conditions. A total of 914 animals were assigned to four groups according to age category and eCG dose: ewe lambs receiving 400 IU (EL400, n = 173) or 500 IU eCG (EL500, n = 169), and adult ewes receiving 400 IU (AE400, n = 301) or 500 IU eCG (AE500, n = 271), following a 7-day intravaginal progesterone-based synchronization protocol. Oestrus rate did not differ among groups (p = 0.861), indicating that both doses were similarly effective in inducing behavioural oestrus, whereas the interval to oestrus onset showed significant main effects of both age category (p < 0.001) and eCG dose (p < 0.001), with no significant age × dose interaction (p = 0.559). Using a 2 × 2 factorial analysis, significant main effects of age category were observed for outcomes including pregnancy rate following oestrus, overall pregnancy rate, and fecundity (p = 0.001, p = 0.009, and p = 0.004, respectively), with higher values in adult ewes than in ewe lambs regardless of eCG dose. In contrast, 500 IU eCG was associated with a greater overall litter size and multiple birth rate than 400 IU eCG (p = 0.039 and p = 0.033, respectively). The age × dose interactions for litter size and multiple birth rate were not statistically significant (p = 0.058 and p = 0.071, respectively). The age × dose interaction for lambing rate was also not statistically significant (p = 0.064). These results indicate that age category and eCG dose were associated with different aspects of reproductive performance. Under the specific seasonal-transition field conditions of this single-breed, single-farm study, selecting the eCG dose according to the reproductive objective may represent a practical management consideration.

The objective of this study was to evaluate the impact of the presence of dominant follicles on the outcome of in vitro embryo production (IVEP) by conducting a comparative analysis of oocyte number, quality, and in vitro embryo development in animals with and without dominant follicles in their ovaries during oocyte pick-up (OPU). The study was conducted by evaluating data obtained from OPU applications, and Holstein heifers in good general health were used in the research. The OPU sessions performed were classified according to the presence of dominant follicles in the ovaries. During oocyte retrieval, two groups were formed: group DFA (dominant follicle-absent) without dominant follicles in either ovary, and group DFP (dominant follicle-present) with dominant follicles. The results demonstrate that the group without dominant follicles in the ovaries exhibited a higher number of quality, total, and viable oocytes ( P < 0.05). In the developmental follow-up conducted after the in vitro culture phase, it was determined that the number of cleaved oocytes and blastocysts was higher in the group without dominant follicles in their ovaries ( P < 0.05). Consequently, it is thought that OPU procedures performed during the phase preceding the establishment of follicular dominance or in ovaries devoid of dominant follicles may positively affect IVEP yield.

The objective of this study was to evaluate the effects of heat stress and nighttime temperature drop on oocyte yield and in vitro embryo production (IVEP) success. The study was conducted on Holstein heifers within the same herd, under similar management and feeding conditions. Each session of ovum pick-up (OPU) was classified into continuous heat stress (CHS; THImax ≥72 and THImean ≥68), high daytime temperature–humidity index (THI) with nighttime recovery (HDT-NR; THImax ≥72 and THImean <68), and thermoneutral (TN; THImax <72 and THImean <68) groups based on environmental THI values. The TN group was found to have a greater number of small- to medium-sized follicles and a higher total number of follicles in comparison to the CHS group (p<0.05). In terms of oocyte yield, the numbers of grade-A, total, and viable oocytes were found to be higher in the TN and HDT-NR groups than in the CHS group (p<0.05). The assessment of the IVEP revealed that the mean number of blastocysts per OPU was lower in the CHS group (p<0.05). Consequently, even when the daytime maximum THI was high, nighttime cooling, reflected by a lower mean THI, appeared to preserve OPU and IVEP performance without adverse effects. Therefore, during the summer season, when the likelihood of heat stress is increased, considering nighttime recovery while planning and conducting in vitro embryo production processes may be an important criterion for improving production success.

This study aimed to evaluate the effects of graafian follicular fluid on embryo development parameters during the in vitro maturation of bovine oocytes. Oocytes collected from 20 clinically healthy Holstein heifers were matured in two different media: one derived from graafian follicular fluid and the other containing a commercial maturation medium (control). Oocyte collection was performed using the transvaginal ovum pick-up technique, and the follicular fluids used for in vitro maturation were obtained from follicles measuring 17–20 mm in diameter. Oocytes from both groups were subjected to identical in vitro fertilization and culture protocols and incubated for 7–8 days. According to the results, maturation, cleavage, and blastocyst development rates in the graafian follicle group were statistically similar to those in the control group (p > 0.05). Although the numerical blastocyst yield was higher in the control group, the difference was not statistically significant. These findings indicate that laboratory-prepared graafian follicular fluid may serve as a viable alternative to commercial media for in vitro maturation and may contribute to reducing the costs of embryo production. However, standardization studies are required to control the physical and biochemical variations that may influence the effectiveness of follicular fluid.

This study employed Akkaraman sheep aged between 2 and 6 years, with a live weight ranging from 53 to 68 kg, sourced from four farms. Three of these farms utilized the same pasture, while the fourth employed a different one. The pastures where the sheep were grazed were categorized as either poor (Group I) or medium (Group II, III and IV) quality. For estrus synchronization, intravaginal progesterone (P4) impregnated sponges were inserted into ewes in Groups I and II for 9 days during the breeding season, taking into account the ram availability in the facility. PGF2α was administered 2 days before the removal of the sponge and 500 IU PMSG was administered after removal. In Group III, where flushing was applied, barley was given at a rate of 300 g/day per head. In group IV, no treatment was applied. Estrus detection was performed using teaser rams, and then ewes were kept with fertile rams in the same environment. The reproductive performance metrics of ewes across experimental groups were assessed, revealing notable variations. Ewe estrus rates were consistently high, ranging from 88.0% to 98.3%, with Group II exhibiting the highest rate. Similarly, parturition rates ranged from 74.5% to 97.7%, with Group II showing the highest rate. Twin births varied substantially, with Group III displaying the highest rate at 66.4% compared to 11.8% in Group I. Litter size ranged from 1.06 to 1.25. Group III exhibited a higher number of ewes that did not give birth. In both Group II and Group III, superior results were achieved across all parameters checked except for litter size. In Groups I and IV, the infertility rate was higher than in the other groups. However, the litter size of Group IV was still higher than Group I. If flushing is applied together with P4-based synchronization to ewes grazing on medium-quality pasture, fertility should be expected to improve significantly. In this study, the comparison was made between the effects of pasture on fertility with P4 application, and the effects of P4 and flushing on fertility in farms utilizing the same pasture.

Prostaglandins may be one of the important factors affecting the development and quality of the embryo in in vitro production (IVP) and may have an inhibitory effect on the development of the embryo. The supplementation of non-steroidal anti-inflammatory drugs (NSAIDs) in the in vitro culture medium may facilitate embryo development. The objective of this study was to assess the effect of non-steroidal anti-inflammatory drugs on embryo development and quality during bovine in vitro embryo culture. The study involved the performance of a series of procedures, including in vitro embryo production processes, the supplementation of different NSAIDs in the in vitro culture, and the evaluation and staining of embryos. In the initial 3 d of the in vitro culture stage, three different NSAIDs were administered to the groups: flunixin meglumine (FM), meloxicam (Mel), and carprofen (Car). No treatment was applied to the control group at this stage. All groups were incubated in the same culture medium, with the solutions being changed starting from the fourth day of the in vitro culture. On the seventh day of culture, the embryos were evaluated according to their developmental stages and quality. Subsequently, the developing embryos were subjected to differential staining and the TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) method for the assessment of their developmental competence, quality, and apoptotic index. Following the supplementation of NSAIDs in the culture medium, the blastocyst formation rates were found to be higher in the FM, Car, and Mel groups compared to in the control group (P<0.05). Furthermore, the inner cell mass, trophectoderm, and total cell counts were observed to be higher in the FM, Car, and Mel groups in comparison to the control group. In addition, the number of apoptotic cells and the apoptotic index were found to be lower in the FM, Car, and Mel groups compared to the control group. Consequently, it was established that the supplementation of non-steroidal anti-inflammatory drugs in the culture medium during in vitro embryo production resulted in an enhanced rate of blastocyst development and an improved quality of blastocysts.

The objective of this study was to evaluate the relationship between plasma leptin levels in the early and late luteal periods of cows and conception rate. In the present study, the ovsynch + progesterone (P4) protocol was employed in 50 Holstein cows. Blood samples were collected on the 5th and 18th days following artificial insemination, and the levels of leptin and progesterone were subsequently measured. Subsequent to artificial insemination, mean leptin levels in the early (day 5) and late (day 18) luteal phases of the cows were measured as 5.96 ± 2.54 and 8.02 ± 4.14 ng/mL, respectively. Levels of leptin in the blood of pregnant cows on both day 5 (9.01 ± 4.40 ng/mL) and day 18 (12.04 ± 6.49 ng/mL) were higher than those in the blood of non-pregnant cows (4.44 ± 3.83 ng/mL and 6.01 ± 4.93 ng/mL, respectively). The findings revealed that progesterone levels on the 5th day following artificial insemination exhibited higher mean values (2.11 ± 0.64 ng/mL) in pregnant cows as compared to non-pregnant cows (1.49 ± 0.51 ng/mL). Furthermore, a higher level of progesterone was observed on day 18 in pregnant cows (8.89 ± 2.01 ng/mL) in comparison to non-pregnant cows (5.22 ± 2.21 ng/mL) (p<0.05). The study revealed that levels of the hormones leptin and progesterone were elevated in pregnant cows during the early and late luteal phase, in comparison to non-pregnant cows. However, no correlation was determined between P4 and leptin. The conclusion drawn was that, while there was a possibility that leptin levels could have an effect on the process of pregnancy and implantation, no relationship was found between progesterone and leptin levels

The aim of this study is to determine the effects of different treatments used to synchronize follicular waves prior to superstimulation of responses and in vitro embryo production (IVEP). The study used 12 healthy Holstein heifers. In GnRH + P4, an intravaginal progesterone (P4) device was inserted into the vagina on a random day of the estrous cycle, and 10 µg of the gonadotropin-releasing hormone (GnRH) was administered intramuscularly at the same time. After these applications, 25 mg of PGF2α was administered intramuscularly on the third and fourth days of treatment. The intravaginal progesterone device was removed on day 5. At the same time, 125 µg of follicle-stimulating hormone (FSH) was administered intramuscularly as a single dose. Two days after the FSH injection, oocytes were retrieved using transvaginal ultrasound. In contrast to GnRH + P4, hCG + P4 was performed with 1500 IU hCG (human chorionic gonadotropin) injection instead of GnRH. In DFR + P4, dominant follicles were removed. In the control group, the oocytes were collected on a random day of the estrous cycle. The ovarian follicles were measured by ultrasound prior to oocyte collection. The number of medium-diameter follicles (3–8 mm) was found to be greater in hCG + P4 and DFR + P4 than in the control group (p<0.05). It was determined that the numbers of viable oocytes, Grade A oocytes, cleaved oocytes, and blastocysts obtained per ovum pickup (OPU) were greater in hCG + P4 and DFR + P4 than in the control group (p<0.05). In addition, the numbers of Grade A oocytes and blastocysts obtained per OPU were greater in the DFR + P4 group than in the GnRH + P4 group (p<0.05). As a result, it was thought that synchronization of follicular wave emergence with DFR and hCG in the short synchronization protocols used before superstimulation could increase the success rate of OPU/IVEP programs.

Backgraund: The first step in the in vitro embryo production (IVEP) procedure is to obtain high-quality and viable oocytes. Therefore, the ovum pick-up (OPU) method was developed in cattle. Ovum pick up in cattle is usually performed once or twice a week. However, when a fixed time follicular aspiration procedure is planned, the OPU application is conducted on different days of the donor's estrous cycle. Furthermore, there is no recommendation as to the optimum day within the estrous cycle for OPU. Therefore, the main objective of the present study was to determine the effect of OPU application on oocyte yield, quality and blastocyst rates on different days of the estrous cycle. Materials, Methods & Results: In the study, 18 Holstein heifers received OPU on days 2-3, 4-7, 8-12 and 13-16 of the estrous cycle. The OPU application was performed once in one oestrus cycle for all donors. The following OPU application waited at least one estrous cycle. Grade A quality oocytes were obtained in greater numbers in D 2-3 and D 4-7 groups than in D 13-16 group (P < 0.05). There was no difference in other oocyte quality and total number of oocytes between the groups. The number of viable oocytes was similar between D 2-3 and D 4-7 groups, but greater than D 13-16 group (P < 0.05). Concurrently, the number of viable oocytes was greater in D 4-7 group than in D 8-12 group (P < 0.05). There was no difference between D 2-3 and D 8-12 groups in terms of viable oocyte number. The number of blastocysts in D 2-3 and D 4-7 groups was greater than D 8-12 and similar to D 13-16 (P < 0.05). Discussion: A follicle may be in 1 of 4 phases during the follicular wave: growth, dominance, static, or regression. In present study, the greater number of oocytes with greater quality and viability rate in D 2-3 and D 4-7 groups is thought to be due to the absence of follicles in the dominant stage in these two groups. In OPU/IVEP method, a greater number of oocytes per donor increases the rate of blastocysts and viable embryos and accordingly positively affects the post-transfer pregnancy rate. In current study, the number of Grade A oocytes and viable oocytes were greater in D 2-3 and D 4-7 groups of the cycle compared to D 13-16 group of the cycle. The reason for this is that when OPU is used on days 13-16 of the cycle, different follicular groups can be found on the ovary. In addition, the present study demonstrated that the number of viable oocytes and blastocysts was greater in the D 4-7 group compared to the D 8-12 group. This may be due to the greater number of atresia follicles (subordinal follicles) between days 8-12 of the cycle (compared to days 4-7) and the lower developmental competence of oocytes in the subordinal follicle. The most significant factors influencing the success of an in vitro embryo production process are the quality and viability of the oocyte. In the present study, the number of Grade A oocytes was greater in the D 2-3 and D 4-7 groups than in the D 13-16 group, but there was no difference in the number of blastocysts. However, in parallel with the number of viable oocytes, the number of blastocysts obtained in groups D 2-3 and D 4-7 was greater than in group D 8-12. In conclusion, the determination of the appropriate day of the cycle for OPU will rule out synchronisation or stimulation of the follicular wave and ablation of the dominant follicle. Therefore, the oocyte quality, number and most importantly the number of blastocysts can be increased by performing OPU between 2-3 or 4-7 days of the estrous cycle. Keywords: blastocyst, holstein heifer, luteal phase, oocyte quality, ovum pick up.