The advent of transported cooled semen significantly altered the logistics of the equine breeding industry. Shipping semen to mares rather than mares to stallions is incredibly more convenient; however it has resulted in the need for increased proficiency in semen processing techniques on the part of the stallion manager and expertise in reproductive technology and artificial insemination on the part of the field practitioner managing the mare. From the perspective of the stallion manager there are a number of factors that can influence the success of cooled transported semen such as stallion collection management, semen handling, extender composition, dilution rate, cooling rate, calculation of insemination dose and transport device. Our blog article this month will address the basic techniques for proper collection, evaluation and processing of stallion semen for cooled transport.

How many sperm does it take to get a mare pregnant?
1 billion?...500 million?... One? Actually, any one of those answers could be correct under certain conditions. The only way to really answer that question is... "it depends". Fertilization is a complex process requiring that both the sperm and egg possess a myriad of functional attributes expressed at the right time and in the right place. A motile sperm is not necessarily a fertile sperm. So, how many sperm must be deposited in the mare for "acceptable" fertility? It would seem that this would be the logical basis for determining sperm numbers in an insemination dose for commercially distributed semen. To achieve the goals of both the mare and stallion owner it is necessary for each dose of semen to contain sufficient numbers of functionally competent sperm to maximize the probability of conception. The relationship between sperm number and fertility is expressed as a typical dose response curve (see figure1). However, the slope of the curve and the maximum level of fertility are different for individual stallions.

In our newsletter last month, we talked about getting organized and ready for foaling out your mare (click here for this news article). Being prepared for the foaling process is of paramount importance, in order to have an enjoyable and successful outcome for the mare, foal, breeders, owners, and attendants. As you are preparing your barn for the foaling, don’t forget that the mare has a chorus of events taking place internally to prepare her body for parturition, transition to lactation, and uterine involution. Whether these events are noticeable or not, they are a necessity for the proper progression of labor and delivery. In our blog article this month Dr. Scofield reviews the stages of parturition and summarizes the hormonal events that are occurring with your mare during this incredible physiological process.

Managing the equine estrous cycle is a common procedure performed by many broodmare managers and veterinarians. Copious research has elucidated many aspects of the equine estrous cycle and allowed veterinarians the tools to manage a mare’s cycle to provide the optimal breeding times, effectively use artificial insemination, induce ovulation, synchronize mares, induce superovulation, advance the onset of the breeding season, terminate pregnancy, as well as a manage a host of other reproductive conditions and diseases. In this article we take a look at the use of progesterone and estradiol (P&E) as therapy in the mare.