The vagina in most pregnant mares has a thicker mucoid secretion, causing the vaginal walls to stick to each other thus forming a barrier to ascending infections. Direct visualization of the vaginal vault and cervix of a pregnant mare may be indicated when bleeding is evident at the vulva or when a vaginal discharge is noted in order to ascertain the origin. This chapter discusses the step by step procedure for speculum examination of the pregnant mare, and outlines the equipment and supplies needed for this purpose. It also outlines the potential risks involved during speculum examination.
Characteristic changes occur in the mare's reproductive tract during pregnancy. Many of these changes can be evaluated by palpation of the reproductive tract per rectum. This chapter discusses the processes involved in determination of pregnancy by palpation per rectum. The accuracy of pregnancy diagnosis per rectum depends on the stage of gestation, individual mare characteristics (straining, peristalsis, rectal lumen diameter, etc.), and skill of the clinician. During the course of the pregnancy, the uterine wall gradually thins and loses tone over the developing conceptus. The pregnant uterus enlarges and changes in size, shape, and orientation as the pregnancy advances. Ultrasonography has become the preferred technique for detecting early pregnancy and monitoring ovarian and uterine function. Nonetheless, accurate palpation of the (tone of the) pregnant uterus and cervix is not to be neglected, as it provides important information on the (hormonal) status of the pregnancy.
The oviduct plays a critical role during fertilization and early embryonic development. This chapter describes the starch granule test for the diagnosis of oviductal patency. The starch granule test involves the deposition of a starch suspension onto the ovarian surface and the subsequent recovery of starch from the uterus or cervix. One oviduct can be tested at a time. The chapter discusses step by step procedure for the diagnosis of oviductal patency in mare, and lists the equipment and supplies needed. The starch granule test requires individual testing of each oviduct on separate estrous cycles.
Blockage of one or both oviducts with intraluminal gelatinous masses can result in reduction of fertility in the mare. The starch granule test has limitations for evaluation of oviductal patency in the mare. Consequently, fluorescent microspheres have been used as an alternative to evaluate oviductal patency. This chapter discusses the processes involved in transvaginal ultrasound technique and laparoscope technique. Transvaginal deposition may result in a variable amount of beads entering the infundibulum; whereas, laparoscopic cannulation results in more accurate placement of beads. Laparoscopic deposition does, however, require a certain technical skill and specialized equipment. Laparoscopic deposition of beads also allows for direct observation of the oviduct. Mares with oviductal pathology may exhibit oviductal swelling, and an increase in vascularity or adhesions.
Digital examination of the vagina and/or cervix is indicated when performing a breeding soundness examination on a mare and typically will be performed in conjunction with the examination of the vagina and cervix by speculum. It may also be indicated in postpartum mares in order to diagnose vaginal or cervical trauma. The goal of the exam indicates whether digital palpation of the vagina and cervix should be performed during estrus or diestrus. A digital examination of the vagina and cervix during estrus is indicated in the assessment of fertility in older maiden mares since failure of cervical relaxation is one factor attributed to reduced fertility. This chapter discusses step by step procedure and necessary conditions for performing digital examination on mare's vagina and cervix.
Blockage of one or both oviducts with intraluminal gelatinous mases consisting of a mixture of collagen, fibroblast cells, and other debris, can result in reduction of fertility in the mare. Oviductal flush techniques are reserved for mares that have a prolonged history of infertility, with good breeding management, bred to fertile stallion(s), and that have no other significant reproductive abnormalities noted during a breeding soundness evaluation. This chapter discusses the processes involved in retrograde oviductal flush (laparotomy approach) technique and normograde oviductal flush (laparotomy and laparoscopic approaches) technique. A unilateral ovariectomy may be performed in the event of irreversible occlusion or oviductal rupture. Flushing the oviducts provides diagnostic information on oviductal patency and at the same time often provides therapeutic intervention in affected mares.
Thorough clinical inspection and palpation of external genitalia of a stallion provides information about breeding potential and permits the detection of reproductive abnormalities. In addition, ultrasonography of the external genitalia is now used routinely as an adjunct to the routine breeding soundness examination of the stallion and is an excellent diagnostic tool in the evaluation of suspected reproductive pathology. This chapter briefly discusses some safety and restraint techniques for performing the palpation and ultrasonography. It discusses step by step procedure for performing the palpation and ultrasonography of testis, epididymis, and spermatic cord of the stallion.
The most common cause of dystocia in the mare is malposture, especially retention of the front legs and/or head. Failure of the foal to be properly orientated can prevent normal passage through the birth canal. Intervention is often required in a dystocia to assist with delivery of the foal. The ultimate goals are to save the life of the foal, save the life of the mare, and to preserve the future fertility of the mare. The most common causes of dystocia in the mare, categorized by management difficulty, are presented in this chapter. Mild dystocias are commonly managed on the farm by foaling personnel. More complicated dystocias may require advanced training or experience and often need veterinary intervention. The chapter discusses dystocia management, and outlines the equipment and supplies needed for this purpose.
The Hannover artificial vagina (AV) is the most commonly used model in Europe. This model AV holds approximately 1–3 liters of water and is considerably lighter than the Colorado model, which holds 6–8 liters of water. The Hannover model is composed of a plastic case with a leather handle and a single rubber liner. The hard case has a large circular opening on one end through which the stallion's penis will enter and a smaller circular opening on the other end. The smaller opening is off-centered, forming a dead end that will create pressure on the erect penis. If the stallion does not ejaculate one can either increase or decrease AV pressure, adjust the water temperature, or remove the disposable plastic liner. This chapter outlines the step by step procedure for the Hannover artificial vagina, and equipment and supplies needed.
Clinical studies have reported that topical administration of prostaglandin E2 (PGE2) onto the surface of the oviduct in mares with unexplained fertility has resulted in a resumption in fertility in a high proportion of treated mares. Equine embryos secrete PGE2 which promotes passage of the embryo through the oviductal isthmus into the uterus. Unfertilized oocytes and non-viable embryos do not produce PGE2 and are consequently retained at the junction of the ampulla and isthmus. This chapter describes the technique of laparoscopic application of PGE2 onto the oviductal surface. Proper selection of candidate mares is one of the most important considerations for potential PGE2 treatment. Blockage of the oviduct(s) should be considered as a cause for infertility in a mare that has historically produced live foals if all other common causes of infertility are evaluated first and addressed.
Examination of the stallion's accessory sex glands should be part of a routine breeding soundness evaluation and may provide valuable information in a stallion with fertility issues. The examination is performed by a combination of palpation and ultrasonography per rectum. This chapter discusses the technique for palpation and ultrasonography of the accessory sex glands of stallion. In the sexually rested animal, the parenchyma will appear heterogenous gray-white and contains multiple small anechoic fluid-filled pockets or bands radiating laterally. Pathology of the accessory sex glands of the stallion are uncommon and primarily consist of blocked or plugged ampullae or infection of the vesicular glands. Treatment consists of frequent collection attempts to remove the accumulated spermatozoa, manual massage of the ampullae per rectum, and administration of oxytocin to stimulate ampullar smooth muscle contractions.
