Browsing by Author "Gumen, Ahmet"

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Comparison of Synchronisation and Fertility After Different Modifications of the Ovsynch Protocol in Cyclic Dairy Cows
(Akademiai Kiado Zrt, 2014) Yilmazbas-Mecitoglu, Gulnaz; Karakaya, Ebru; Keskin, Abdulkadir; Gumen, Ahmet; Koc, Volkan; Okut, Hayrettin
The objectives of this study were to evaluate the effects of (1) double doses of PGF(2 alpha) administration or (2) an exogenous progesterone (CIDR) applied concurrently with, or (3) the day after, first GnRH of Ovsynch (GnRH-1), on synchronisation and fertility during the Ovsynch protocol. All cows (n = 378) received the Ovsynch protocol (GnRH-7d-PGF(2 alpha)-56h-GnRH-18h-TAI). The 'OVS' group (n = 105) received only the Ovsynch protocol. The 'OVS-PGF' group (n = 118, GnRH-7d-PGF(2 alpha)-12h-PGF(2 alpha)-44h-GnRH-18h-TAI) received an extra dose of PGF(2 alpha) 12 h later on Day 7. The 'OVS-7CIDR' group (n = 78, GnRH+CIDR-7d-PGF(2 alpha)-56h-GnRH-18h-TAI) received a CIDR for 7 days between GnRH-1 and PGF(2 alpha). In the 'OVS-6CIDR' group (n = 77, GnRH-24h-CIDR-6d-PGF(2 alpha)-56h-GnRH-18h-TAI), CIDR was applied one day after GnRH-1 and removed 6 days later. When all cows were evaluated, the responses to GnRH-2 were higher (P = 0.005) in cows that responded to GnRH-1 (95.4%) compared to the cows that did not respond (87.6%). The pregnancy rates at 31 and 62 days for each group were 48.6% and 42.9% in the OVS, 54.2% and 52.5% in the OVS-PGF, 52.6% and 48.7% in the OVS-7CIDR, and 55.8% and 49.3% in the OVS-6CIDR groups. Thus, none of the three different treatments has an effect on increasing the outcomes of the Ovsynch protocol in cyclic lactating dairy cows.
The Effect of Intrauterine Cephapirin Treatment After Insemination on Conception Rate in Repeat Breeder Dairy Cows Subjected To the Progesterone-Based Ovsynch Protocol
(Tubitak Scientific & Technological Research Council Turkey, 2012) Gumen, Ahmet; Yilmazbas Mecitoglu, Gulnaz; Keskin, Abdulkadir; Karakaya, Ebru; Alkan, Ali; Tasdemir, Umut; Okut, Hayrettin
Subclinical endometritis contributes to repeat breeder syndrome in dairy cows. This study evaluated the effect of intrauterine cephapirin benzathine administration aft er timed artificial insemination (TAI) on the conception rate (CR) in repeat breeder dairy cows. To determine the antibiotic effects, all cows (n = 335) that had more than 3 services with no clinical abnormalities of the reproductive tract received the same combined synchronisation protocol: an ear implant containing progestagen using the Ovsynch protocol and a third gonadotropin-releasing hormone (GnRH) administration 7 days aft er TAI. Cows in the treatment group (TRT; n = 160) received intrauterine cephapirin 12 h aft er TAI, and cows in the control group (CON; n = 175) did not receive intrauterine antibiotics. The percentage of cows that responded to the first (67.5% in TRT, 70.9% in CON) and second (98.8% in TRT, 97.1% in CON) GnRH of Ovsynch was similar between the groups. In addition, the response to the third GnRH administration aft er TAI (88.1% in TRT, 83.9% in CON) did not differ between the groups. However, there was no effect of the cephapirin administration on CR on days 31 and 62 in the repeat breeder cows (43.8% in TRT and 44.0% in CON; 39.4% in TRT and 40.6% in CON, respectively). Thus, post-TAI intrauterine cephapirin administration was not found to be useful for the treatment of potential subclinical endometritis in repeat breeder dairy cows.
The Effect of Ovulatory Follicle Size at the Time of Insemination on Pregnancy Rate in Lactating Dairy Cows
(Tubitak Scientific & Technological Research Council Turkey, 2016) Keskin, Abdulkadir; Mecitoglu, Gulnaz; Bilen, Ebru; Guner, Baris; Orman, Abdulkadir; Okut, Hayrettin; Gumen, Ahmet
The aims of this study were to determine the factors that affect follicle size at the time of artificial insemination (AI) and to detect the relationship between ovulatory follicle size at the time of AI and pregnancy rate in dairy cows. A total of 1428 follicle size measurements were obtained from Holstein-Friesian (HF) and Swedish Red (SR) cows that were inseminated with the fixed-timed AI protocols used in this study. Follicle size was affected by breed (P - 0.0001), milk production (P - 0.01), parity (P - 0.05), and season (P = 0.04). Follicle size was greater (P = 0.0001) in the HF (15.55 mm) than the SR cows (14.88 mm). Multiparous cows had larger (P = 0.04) follicles (15.35 mm) than the primiparous cows (15.07 mm). Cows with follicle sizes between 13.5 and 17.5 mm were more likely to be pregnant than cows with other sizes follicles (P < 0.01). Embryonic loss was lower (P < 0.01) in cows with follicle sizes between 13.5 and 16.5 mm. Thus, the follicle size was affected by breed, milk production, parity, and season. Pregnancy and embryonic loss in lactating dairy cows were significantly related to follicle size.