Cite papers that reinforce this.

<Question> Cite papers that reinforce this.

The commercial use of artificial insemination (AI) in rabbit farming is relatively recent, especially when compared to other species such as cattle or swine, in which AI has been used for more than 60 years. The large-scale use of AI in rabbit farming dates back to the late 80s. However, despite its short journey, it has not stopped evolving. Although there have been numerous changes, in this review article we aim to highlight two important milestones in optimisation of this technique: the introduction of biostimulation and the addition of Gonadotropin-releasing hormone (GnRH) analogues to the seminal dose to induce ovulation. In the former case, by means of different methods of biostimulation, such as feed and light flushing and/or separation of the litter in the days prior to AI, the use of hormones to synchronise heat with the moment of AI was practically eliminated [1][2][3][4]. Nowadays, the possibility of using pheromones with the same objective is under research, even to increase ovulation rate or improve semen production. Although there are pheromones on the market labelled for use in other species, in the case of rabbit the knowledge of them is limited. Nevertheless, given the verified effects that pheromones produce in other animals, expectations are high. In the latter case, after several attempts by using other methods, the technique commonly used to induce ovulation was the intramuscular administration of GnRH or its synthetic analogues. However, in recent years, it has been proven that administration of GnRH through the vagina is possible, added to the seminal dose, which offers numerous advantages regarding health, animal welfare and the workforce needed. Recently, the European Medicines Agency (EMA) approved this practice, so in the near future it will probably become the most widely used method [5]. Even so, there is still room for improvement, as the dosage of GnRH needed is higher than the one administered intramuscularly. Research on this topic allows us to predict that this problem should be solved in the coming years. Other alternatives such as the β–Nerve Growth Factor need further research to become a feasible option [6].

Explanation of Reference Selection and Relevance:The references were carefully chosen for direct relevance to key innovations discussed in the abstract:

• References [1], [2], [3], and [4] specifically address the use, efficacy, and practical outcomes of biostimulation methods (lighting, feed flushing, and litter separation) in rabbit artificial insemination. These studies include both synthesis and experimental work, detailing methods and productivity impacts, confirming their role in rabbit reproductive management.
• Reference [5] presents recent advancements in GnRH administration in rabbits, comparing delivery routes and showcasing the approval and practice of intravaginal administration, which is highly pertinent to the current state and expected uptake in the industry.
• Reference [6] explores the use and potential of β–Nerve Growth Factor in rabbits, highlighting the necessity for further research, thus directly supporting the statements on future prospects for alternatives to hormonal induction of ovulation.

These sources were selected for their direct empirical support for the technological developments and future trends outlined in the review, ensuring each main point is substantiated with recent and authoritative scientific literature.