19 An Efficient Noninvasive Alternative Recipient Preparation in Swamp Buffalo Using the Ovsynch Protocol

Abstract

Although intravaginal progesterone supplement protocols are commonly used to prepare cattle and river buffalo for insemination or embryo transfer, swamp buffalo have unique reproductive characteristics (such as difficulty of oestrous detection and a small reproductive tract) that make this procedure problematic. Ovulation synchronization (Ovsynch) is a practical alternative preparatory program that does not require oestrous detection and is used worldwide for cattle and river buffalo breeding. Published studies on the efficacy of its use in swamp buffalo, however, are rare. Our objective was to determine the efficacy of the Ovsynch regimen in swamp buffalo in terms of conception rate, economic cost, and potential health complications. Thirty healthy swamp buffaloes (n = 24 cows and n = 6 heifers) were selected by a breeding soundness examination (BSE) as in our previous study (Chaikhun-Marcou et al. 2017 Agric. Sci. J. 48(Suppl.), 929-938). The animals had the following characteristics: >300 kg of body weight, a body condition score of 2.5 to 3.5/5, cervix diameter >2.5 cm, and ovarian diameter >1.5 cm with a dominant follicle (with or without corpus luteum). The standard Ovsynch program was applied in the animals during January to March 2017. All buffaloes were fixed-time inseminated at 20 ± 2 h and 32 ± 2 h after the 2nd gonadotropin-releasing hormone (GnRH) injection. Pregnancy diagnosis was detected by plasma progesterone analysis on Day 24 after insemination (≥1 ng mL⁻¹). Our oestrous synchronization rate, published in a previous study (Chaikhun-Marcou et al. 2017 Agric. Sci. J. 48(Suppl.), 929-938), was 96.67% (n = 29/30). The conception rate was 70% (n = 21/30). This result is much higher than a previous Ovsynch study in swamp buffalo, which was 34% (n = 18/52) (Chaikhun et al. 2010 Theriogenology 74, 1371-1376). This difference demonstrates the importance of pre-screening animals for BSE before subjecting them to this procedure. If this pre-selection protocol is applied, the Ovsynch program, as shown in this study, can be a convenient, effective, and noninvasive preparatory procedure for insemination. Because recipients of both AI and embryo transfer require the same basic biological preconditions, the Ovsynch protocol should be an equally effective preparation for this procedure. Ovsynch, moreover, requires much less labour (only 3 animal handling sessions, with no need for complicated heat detection), entails fewer possible complications (such as the danger of vaginitis when using an intravaginal progesterone device, which can lead to problems with embryonic implantation), and is economically affordable (approximately US$20/animal). In conclusion, the Ovsynch program, combined with BSE pre-screening, could be a practical, stress-free procedure for preparation of swamp buffalo embryo transfer recipients in the near future.

This research was sponsored by Agricultural Research Development Agency (PRP5805011500).