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Publication
Featured researches published by Ahmet Gümen.
Journal of Feline Medicine and Surgery | 2009
Abdulkadir Keskin; Gulnaz Yilmazbas; Rahsan Yilmaz; Musa Ozgur Ozyigit; Ahmet Gümen
In this report, multiple abnormalities (bilateral ovarian cysts, cystic endometrial hyperplasia and pyometra (CEH–P), mammary adenoma, fibrosarcoma and cystic-papillary adenocarcinoma) identified in a queen continually administered medroxyprogesterone acetate (MPA) for 9 years are described. An 11-year-old domestic shorthair intact queen was presented for reduced appetite, polyuria, polydipsia, abdominal distension, and mammary mass. Pyometra was diagnosed based upon clinical, ultrasonographic and radiographic examinations. Mastectomy and ovariohysterectomy (OHE) were performed for treatment. Bilateral ovarian cysts were detected during OHE. Histopathologically, follicular ovarian cysts, CEH–P, and benign and neoplastic mammary lesions were identified. We suggest that, the pathological abnormalities may have been attributed to adverse effects of prolonged administration of MPA.
Reproduction in Domestic Animals | 2011
Ahmet Gümen; Abdulkadir Keskin; G Yilmazbas-Mecitoglu; E. Karakaya; M.C. Wiltbank
Dry period and early post-partum management are decisive factors for fertility in lactating dairy cows. Previous studies have shown that decreased dry matter intake (DMI) and increased non-esterified fatty acids (NEFA) negatively affect fertility and subsequent milk production. The traditional dry period decreases DMI prior to parturition, resulting in a decrease in energy intake. A negative energy balance increases NEFA concentration, and increased NEFA may impair the immune system, especially by decreasing neutrophil function prior to parturition. Earlier studies have shown that post-partum health disorders, including retained placenta and metritis, were correlated with periparturient neutrophil function. In addition, decreased DMI is also linked to a reduced body condition score (BCS) in dairy cows. These events in the periparturient period negatively affect fertility. Some manipulation, such as shortening the dry period, may be a solution to increased DMI in the periparturient period, preventing post-partum disorders and subsequent fertility issues. This article aims to explain the effects of shortening the dry period on reproduction and early post-partum treatments to improve fertility. In addition, timed artificial insemination protocols will be discussed for use during the post-partum period to improve fertility in dairy cows.
Reproduction in Domestic Animals | 2014
E. Karakaya; G Yilmazbas-Mecitoglu; Abdulkadir Keskin; Ali Alkan; U Tasdemir; J.E.P. Santos; Ahmet Gümen
The aim of this study was to compare pregnancy per artificial insemination (P/AI) after timed AI with sex-sorted sperm (SS) or conventional semen (CS) in lactating dairy cows. Cyclic cows (n = 302) were synchronized by Ovsynch and randomly assigned into two groups at the time of AI. Cows with a follicle size between 12 and 18 mm and clear vaginal discharge at the time of AI were inseminated with either frozen-thawed SS (n = 148) or CS (n = 154) of the same bull. A shallow uterine insemination was performed into the uterine horn ipsilateral to the side of probable impending ovulation. Pregnancy per AI on Day 31 tended (p = 0.09) to be less for SS (31.8%) than CS (40.9%). Similarly, P/AI on Day 62 was less (p = 0.01) for cows inseminated with SS (25.7%) compared with CS (39.0%). The increased difference in fertility between treatments from Days 31 to 62 was caused by the greater (p = 0.02) pregnancy loss for cows receiving SS (19.2%) than CS (4.8%). Cow parity (p = 0.02) and season (p < 0.01) when AI was performed were additional factors affecting fertility. Primiparous cows had greater P/AI than multiparous cows both on Day 31 (41.7% vs 25.0% in SS and 53.0% vs 31.8% in CS groups) and on Day 62 (33.3% vs 20.5% in SS and 48.5% vs 31.8% in CS groups). During the hot season of the year, P/AI on Day 31 was reduced (p = 0.01) in the SS group (19.6%) when compared with the rates during the cool season (38.1%). In conclusion, sex-sorted sperm produced lower fertility results compared to conventional semen even after using some selection criteria to select most fertile cows.
Acta Veterinaria Hungarica | 2014
Gulnaz Yilmazbas-Mecitoglu; E. Karakaya; Abdulkadir Keskin; Ahmet Gümen; Volkan Koc; Hayrettin Okut
The objectives of this study were to evaluate the effects of (1) double doses of PGF2α 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-PGF2α-56h-GnRH-18h-TAI). The OVS group (n = 105) received only the Ovsynch protocol. The OVS-PGF group (n = 118, GnRH-7d-PGF2α-12h-PGF2α-44h-GnRH-18h-TAI) received an extra dose of PGF2α 12 h later on Day 7. The OVS-7CIDR group (n = 78, GnRH+CIDR-7d-PGF2α-56h-GnRH-18h-TAI) received a CIDR for 7 days between GnRH-1 and PGF2α. In the OVS-6CIDR group (n = 77, GnRH-24h-CIDR-6d-PGF2α-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 out-comes of the Ovsynch protocol in cyclic lactating dairy cows.
Reproduction in Domestic Animals | 2018
Ebru Karakaya-Bilen; Gulnaz Yilmazbas Mecitoglu; Abdulkadir Keskin; Barış Güner; Enes Serim; J.E.P. Santos; Ahmet Gümen
The objective was to compare pregnancy per artificial insemination (P/AI) with conventional (CS) or sex-sorted semen (SS) in dairy cows subjected to one of the three timed AI protocols. Cows (nxa0=xa0356) were randomly assigned to synchronization with Ovsynch (OVS), Presynch-Ovsynch (PO) or Double-Ovsynch (DO) and inseminated on Day 77xa0±xa03 postpartum with either frozen-thawed SS (nxa0=xa0182) or CS (nxa0=xa0184) of the same bull. More cows were cyclic at the beginning of breeding Ovsynch increased (pxa0<xa00.01) with presynchronization and it was greater for DO than PO (OVSxa0=xa078.5%, POxa0=xa085.1%, DOxa0=xa095.6%). Overall, P/AI for SS and CS increased with presynchronization (pxa0<xa00.05) on Days 31 (OVSxa0=xa035.5%, POxa0=xa047.1%, DOxa0=xa048.3%) and 62 (OVSxa0=xa030.1%, POxa0=xa043.8%, DOxa0=xa043.9%). Regardless of synchronization treatments, insemination with SS reduced P/AI (pxa0<xa00.02) on Days 31 (38.1% vs. 50.6%) and 62 (34.5% vs. 45.6%) compared with CS. No interaction was observed between synchronization treatment and type of semen for P/AI, although in cows receiving CS, P/AI was numerically greatest for PO (OVSxa0=xa042.0%, POxa0=xa059.3%, DOxa0=xa049.0%), and in cows receiving SS, it was numerically greatest for those inseminated following DO (OVSxa0=xa027.9%, POxa0=xa035.5%, DOxa0=xa047.6%). Thus, presynchronization improved P/AI in cows inseminated with sex-sorted or conventional semen.
Tierärztliche Praxis Ausgabe G: Großtiere / Nutztiere | 2013
E. Karakaya; G. Alpay; G Yilmazbas-Mecitoglu; A. Alasonyalilar-Demirer; B. Akgül; S. Inan-Ozturkoglu; M. O. Ozyigit; D. Seyrek-Intas; K. Seyrek-Intas; K. Yesilbag; Ahmet Gümen; Abdulkadir Keskin
Turkish Journal of Veterinary & Animal Sciences | 2016
Abdulkadir Keskin; Gülnaz Mecitoğlu; Ebru Bilen; Bariş Güner; Abdulkadir Orman; Hayrettin Okut; Ahmet Gümen
Turkish Journal of Veterinary & Animal Sciences | 2012
Ahmet Gümen; Gülnaz Mecitoğlu; Abdulkadir Keskin; E. Karakaya; Ali Alkan; Umut Taşdemir; Hayrettin Okut
Uludağ Üniversitesi Veteriner Fakültesi Dergisi | 2010
Abdulkadir Keskin; Gülnaz Yilmazbaş; Mecitoğlu; E. Karakaya; Umut Taşdemir; Ali Alkan; Hayrettin Okut; Ahmet Gümen
Uludağ Üniversitesi Veteriner Fakültesi Dergisi | 2010
Abdulkadir Keskin; Ahmet Gümen; Gülnaz Yilmazbaş; Mecitoğlu; E. Karakaya; Umut Taşdemir; Yakup Çelik; Hayrettin Okut