21 DEEP UTERO-TUBAL SEMEN DEPOSITION IN MEDITERRANEAN ITALIAN BUFFALOES USING A NEW ARTIFICIAL INSEMINATION DEVICE

Abstract

The use of AI in the buffalo species is still marginal due to traditional lower conception rates when compared to cattle. However recently a number of studies in this field have revealed a promising increase in the efficiency of synchronization protocols for AI linked to more acceptable pregnancy rates. The possibility of using lower spermatozoa concentration of high quality buffalo bulls for AI without reduction in pregnancy outcome can be an additional offset, especially if such spermatozoa can be sexed and used for better reproductive management in buffalo farms. Within this conceptual framework, a new artificial insemination device for semen deposition near the utero-tubal junction (UTJ) in cattle (Ghent device), developed at the University of Ghent (Belgium), has been used in this study. The Ghent device is made of disposable materials and consists of 2 hollow plastic tubes, wherein a catheter filled with semen is introduced. The outer tube is completely rigid, while the inner tube consists of a rigid caudal end and a flexible cranial tip. The outer plastic tube can move independently from the inner tube. Once the insemination device is introduced into the uterine body, the inner tube with its flexible tip is moved forward. The flexible tip makes it possible to follow the curvature of the contractile uterus of the estrous cow, but excludes the use of Cassou straws. The semen is then expelled from the catheter by means of 0.1 mL of air followed by 0.6 mL of physiological saline solution. To assess the efficacy of the new Ghent device, 67 buffalo cows (Bubalus bubalis) were inseminated during a field trial. Two different insemination methods were used: (1) insemination with the conventional insemination device in the uterine body, and (2) insemination with the Ghent device near the utero-tubal junction ipsi-lateral to the site of ovulation. Artificial insemination was performed twice at 72 and 96 hrs after administration of prostaglandins to buffaloes bearing a functional corpus luteum as recorded during ultrasound monitoring. Conventional inseminations were performed with full (16–20 × 106) and half (8–10 × 106) insemination doses of frozen-thawed semen, while UTJ-inseminations were performed with full, half and quarter (4–5 × 106) insemination doses. When inseminations were performed with the conventional insemination device, halving the insemination dose resulted in a non-significant decrease of conception rates from 53% (8/15) to 42% (8/19). However, no difference in conception rates was observed when UTJ-inseminations were performed with a full, half or quarter standard insemination dose: 50% (6/12), 45% (5/11) and 50% (5/10), respectively. Despite the limited number of inseminations performed, this preliminary field trial demonstrates that the Ghent device is suitable for the insemination of buffaloes under field conditions, and that UTJ inseminations can be performed with only one-fourth of the standard insemination dose without a reduction in conception rates.