INTRODUCTION

Reproductive efficiency plays a crucial role in successful cattle production for both dairy and beef industries. Accurate ovulation timing is a key component of the reproductive cycle because it directly influences the likelihood of fertilization, successful conception, and optimal calving intervals [1]. Globally, delayed ovulation affects approximately 15%–25% of postpartum cows, with higher prevalence reported in high-producing dairy herds and in extensive production systems in Europe, North America, and parts of Asia [2]. Regionally, prevalence varies widely depending on herd management, nutrition, and environmental conditions.

Ovulation irregularities, particularly delayed ovulation, can significantly impair reproductive performance and productivity in cattle [3]. This condition is often difficult to detect clinically, as estrus signs may persist despite delayed ovulation. Delayed ovulation differs from general fertility decline, which may result from multifactorial issues including poor nutrition, infections, or herd management inefficiencies. It is also distinct from cystic ovarian disease (COD) or anovulation, which involve complete absence of ovulation or persistent cyst formation [4]. Therefore, a comprehensive understanding of the physiological mechanisms and factors underlying these disorders is essential.

Delayed ovulation refers to ovulation that occurs later than the normal timeframe after estrus, as opposed to anovulation, which is characterized by the complete absence of ovulation within a single estrous cycle [5]. In cattle, ovulation typically occurs approximately 24–32 h after peak estrus signs [6]. When ovulation is delayed, it can occur several hours or even days later, potentially disrupting the synchrony between ovum release and sperm presence [7]. This asynchrony can reduce the chances of optimal fertilization [2]. Understanding the difference between delayed ovulation and anovulation is crucial, as the management approaches and reproductive interventions required for each condition differ [8].

Delayed ovulation has a significant impact on reproductive performance. One of the main consequences is decreased conception rates due to the mismatch between the timing of ovulation and insemination [9]. Furthermore, calving intervals can be lengthened because of delayed recovery of the reproductive cycle, thereby reducing annual production output [10]. Economic losses associated with delayed ovulation include additional insemination costs, extended calving intervals, reduced milk yield, and delayed generation turnover. Estimated losses per affected cow range from USD 50 to 150 per cycle, depending on herd size and production system [2]. Delayed ovulation is a major contributor to repeat breeding syndrome in cattle, which increases costs for farmers due to repeated inseminations and additional reproductive management [11]. The cumulative impact of these disruptions affects not only individual animal fertility but also the farm’s overall economic efficiency [12].

Although the clinical and economic impacts of delayed ovulation are well understood, scientific publications that comprehensively outline its physiological mechanisms, risk factors, and effective management approaches remain relatively limited [13]. Numerous studies indicate that this condition is influenced by various factors, including nutritional adequacy, hormonal regulation, environmental stress, postpartum health conditions, and genetic factors [14–16]. However, the available scientific evidence is often fragmented and limited to specific populations or contexts. Recent research developments have shown increasing use of technologies such as ultrasonography, hormone profile analysis, and sensor-based estrus detection devices to improve the accuracy of identifying ovulatory disorders [17]. Despite these advances, existing reviews tend to focus either on physiological aspects or on management strategies, without fully integrating the multifactorial causes, diagnostic approaches, and practical reproductive interventions into a single comprehensive overview. Moreover, the implications of delayed ovulation across diverse production systems, as well as the cost-effectiveness of various management practices, are rarely addressed in depth. This lack of a dedicated, standalone synthesis that treats delayed ovulation as a distinct reproductive disorder, separate from general fertility decline, anovulation, or COD, highlights a critical knowledge gap and underscores the need for targeted guidance for veterinarians and livestock practitioners [18].

Despite growing recognition of delayed ovulation as a clinically relevant reproductive disorder, significant gaps persist in the scientific literature. Most studies address isolated aspects such as specific risk factors or diagnostic tools, with limited integration of physiological mechanisms, epidemiological data across production systems, and evidence-based management strategies. There is a notable scarcity of reviews that synthesize cross-disciplinary findings, evaluate the cost-effectiveness of interventions, or provide practical, system-specific recommendations. Furthermore, the long-term impacts on herd productivity, genetic progress, and sustainable cattle farming under varying climatic and management conditions remain insufficiently explored. This fragmen-tation limits the ability of researchers, veterinarians, and producers to implement precise, evidence-based interventions.

The present review aims to provide a comprehensive, integrative synthesis of delayed ovulation in cattle. It encompasses the underlying physiological mechanisms, multifactorial triggering factors, consequences for reproductive performance and farm economics, current diagnostic methods, and available management strategies. By critically analyzing and consolidating current findings from diverse production systems, this review seeks to bridge existing knowledge gaps, highlight practical implications, and identify priority areas for future research. Special emphasis is placed on cross-disciplinary insights to support the development of more precise, sustainable, and evidence-based reproductive management approaches for both dairy and beef cattle production.