Rabbit reproductive performance after insemination with buserelin acetate extender J.S. Vicente a, ⁎ , R. Lavara a , F. Lavara, F. Marco-Jiménez a , M.P. Viudes-de-Castro b a Laboratory of Reproduction Biotechnology, Technology and Science Animal Institute. Polytechnic University of Valencia, Valencia 46022, Spain b Animal Research and Technology Center. Valencian Institute of Agrarian Research. Segorbe 12400, Spain Received 18 April 2007; received in revised form 2 July 2007; accepted 3 July 2007 Abstract Rabbit farmers and insemination centres have established new requirements relating to males (genetic, nutritional and environmental factors) and rabbit insemination techniques. The aim of this study was to evaluate buserelin acetate on the reproductive performance of nulliparous, multiparous lactating and multiparous non-lactating does inseminated on three commercial farms. Two thousand two hundred and three commercial crossbred does belonging to three commercial farms were inseminated with pooled semen from males of two selected meat lines; R line (UPV rabbit selection centres, Spain) in farms 1 and 2, and PS Hyplus 59 line (Grimaud Frère, France) on farm 3. Ejaculates from 12–20 males from each line were pooled and diluted to twelve million sperm per millilitre by adding TRIS–citrate-extender. Diluted semen from each male line was split into two fractions, the first without buserelin acetate added to semen (Control group) and the second fraction was supplemented with 10 μg of buserelin acetate per millilitre (Buserelin group). Receptive females (red colour of vulvar lips) were inseminated with 0.5 mL using a standard plastic curved pipette. Artificial insemination with semen extended with buserelin resulted in lower pregnancy and kindling rates irrespective of the physiological status of females or the farm (78.7% and 76.0% vs 85.8% and 83.4%, buserelin extender group and control respectively, P b 0.01), although does from both treatment groups had a similar litter sizes (10.4 and 9.6 total and alive born, respectively). This study opened up new prospects for changing rabbit insemination procedures. © 2007 Elsevier B.V. All rights reserved. Keywords: Buserelin; Semen extender; Rabbit; Artificial insemination 1. Introduction In the past decade, reproductive control in rabbit has advanced thanks to the development of reproductive technologies such as hormonal and biostimulation prac- tices, increasing receptivity rate of does as insemination techniques allow both the use of better genetic male lines and a new organization system on the farm. Since the first assays with GnRH synthetic analogues applied to ovulation induction in rabbit does took place eighteen years ago (Rodríguez and Ubilla, 1988; Theau- Clément et al., 1990), artificial insemination (AI) has gained increasing interest and has been progressively incorporated into the rabbit industry. Currently, rabbit AI is widely used in European countries. Rabbit farmers and insemination centres have estab- lished new requirements relating to males (genetic, Available online at www.sciencedirect.com Livestock Science 115 (2008) 153 – 157 www.elsevier.com/locate/livsci ⁎ Corresponding author. Tel.: +34 96 387 97 54; fax: +34 96 387 74 39. E-mail address: jvicent@dca.upv.es (J.S. Vicente). 1871-1413/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2007.07.011