Bovine Rectal Palpation
of Animal Sciences,
Anatomical Basis of Rectal Palpation
Manipulation and examination of the reproductive tract of cattle via rectal palpation is possible because of several anatomical features of the cow:
1) As in other species, the reproductive tract of the bovine is suspended from the dorsal body wall by the broad ligament. The posterior part of the tract (vagina, cervix and, sometimes part of the uterus) is located in the pelvic cavity (formed by the two pelvic bones) and the anterior part of the tract hangs over the pelvic brim (uterus, oviduct, ovaries and, sometimes part of the cervix) and is suspended in the abdominal cavity. Moreover, the tract is located immediately below the rectum.
2) The rectum of the cow is large enough to allow insertion of the hand and arm of the palpator. Moreover, the rectal wall is sufficiently pliable to allow one to grasp and reproductive tract structures through the rectal wall.
3) The rectal wall of the cow is strong so that tearing, while possible, is rare. Note the situation is different in other species, notably the mare, where the rectal wall is more subject to damage. Nonetheless, care should be taken when performing rectal palpation of cattle because the rectum can be torn or otherwise damaged.
Features of the Reproductive Tract Ascertained by Rectal Palpation
The cervix can be grasped and manipulated to insert an artificial insemination pipette or embryo flush catheter through the rings of the cervix and into the uterus. The cervix is also sometimes used to pull the reproductive tract further into the pelvic cavity during palpation so as to make palpation of ovarian and uterine structures easier.
The uterus can be palpated to get a rough estimate of endocrine status of the cow. Cows under the influence of estrogen have a uterus with "tone" where the uterus feels turgid and muscular. Cows under the influence of progesterone may have a more flaccid-feeling uterus. A very small uterus can be an indication that a cow is reproductively quiescent or sterile.
After calving, the uterus can be palpated to determine involution (return of the uterus to a pre-pregnant condition; i.e., ready for breeding). The major criteria are size (reduction in size of uterine horns and a return of the horns to a more uniform size (i.e., the horn previously containing the fetus is no longer larger than the other horn), location in the body cavity (more forward into the pelvic cavity) and tone [less meaty" (i.e., large, soft and pliable) and more turgid].
During pregnancy (after ~ d 35-40), it is possible to palpate the presence of the conceptus by feeling for the "fetal slip". The fetal slip refers to the feel of the placental membranes moving through the fingers as the palpator first grasps the uterus and then lets it gradually slip through his fingers. Ultrasonic examination of the uterus can also result in visualization of the fetus.
Follicles can be felt as fluid-filled pliable structures. Note that only a fraction of the number of follicles actually present are usually detected by rectal palpation - ultrasound examination is required to detect all follicles on the ovary. The corpus luteum is a hard structure that often protrudes from the otherwise smooth curvature of the ovary. The best way to learn to identify ovarian structures is to practice using reproductive tracts obtained from a slaughterhouse.
Cystic ovaries are readily identified by rectal palpation as very large ovaries (twice or more in normal size). Cysts are follicular structures that have grown very large in size (>2.5 cm) which persist for 10 or more days and which lead to inhibition of ovulation and nymphomania. Follicular cysts can be luteinized or not. Luteinized cysts (about 30% of cysts) have a thicker wall than nonluteinized cysts. Luteinized follicular cysts can be confused with a fluid-filled corpus luteum which is a normal tructure that does not disrupt the estrous cycle.
Uses of Rectal Palpation
1) artificial insemination
2) non-surgical recovery of embryos for subsequent embryo transfer
3) pregnancy diagnosis
4) postpartum reproductive exam to determine suitability of the animal for breeding and to estimate whether the cow is cyclic.
5) clinical diagnosis of cystic ovarian disease and uterine infections.
Procedure for Examination of the Reproductive Tract by Rectal Palpation
Entering the Rectum
1) The cow is restrained by placing it in a chute or stanchion.
2) The cow is approached in a way that minimizes fright to the animal. Do not make sudden movements or act in a loud, frightening way, especially if the cow is not habituated to people. Dairy cows will usually not kick although some will. One can approach the cow slightly from the side to avoid kicks. The cow can be gently touched on the flank or back to make it aware of the palpator's presence and to allow evaluation of the cow's temperament.
3) Before beginning palpating, the arm used for palpation (either will do; whatever is most comfortable) should be covered with a palpation sleeve. A variety of sleeves are available. One workable alternative is to use an inexpensive, disposable palpation sleeve with a tighter-fitting latex glove fitted over the hand. The palpation sleeve can be attached to the sleeve of the coveralls or work shirt with a hemostat or clothespin.
4) After donning the palpation sleeve, the glove should be lubricated with K-Y
jelly or a commercially-available lubricant such as those sold by Nasco or
5) Approaching the cow while standing somewhat sideways, grab the tail with the ungloved hand and push it aside (for cows prone to kicking, the tail can be raised perpendicular to the cow to prevent kicking). The anus can be identified as the upper of the two openings under the tail (the lower one being the vulva). If there is only one opening present, look around to see which of your co-workers has slipped a bull or steer into the string of animals being palpated.
6) To enter the rectum, form the hand into a cone shape by bringing the fingers and thumb together and use a slight rotary motion to insert the fingers and hand into the rectum. Entering the rectum takes some physical effort because of the strength of the anal sphincter muscle and because of peristaltic contractions in the rectum. The contractions often subside after the arm has been placed in the rectum. If the contractions are especially large (the cow has arched her back to generate additional contractile force), one can have a coworker press down on the animal's spine to lower the pressure. To enter the rectum while strong contractions are taking place, the palpator must use enough force to overcome the contractions while being careful to avoid injuring the cow.
7) After the rectum has been entered, the palpator should remove fecal material from the rectum by using the cupped hand as a rake. Removal of fecal matter is not always necessary if the feces are not abundant or are very soft.
8) It is possible for the cow to suck air into the rectum, especially if the palpator makes many rapid in-an -out motions with the arm. When this occurs, it is nearly impossible to palpate the reproductive tract because the rectum balloons outwards. To reduce the problem, air can sometimes be removed by grasping a fold of the rectal wall and slowly moving it backwards to the anus.
Finding and Palpating Structures in the Reproductive Tract
1) For a new palpator, the cervix is usually the best landmark to help find the reproductive tract. The cervix can be identified as a rope-like or chicken-neck-like structure about 3 inches in diameter that is usually in the pelvic cavity along the midline. Sometimes, the bladder can displace the reproductive tract so that it lies to the right side of the pelvic cavity.
2) The cervix can be picked up and held in the hand. Do not attempt to grab the cervix between thumb and the first two fingers of the hand because it is hard to hold the cervix in this manner. Rather, grab the cervix from the side while placing the the fingers underneath the cervix and the thumb on top. If the reproductive tract is located far forward in the abdominal cavity, one can use the cervix to pull the reproductive tract into the pelvic cavity.
3) The uterus can be identified and examined by following the cervix forward. To do so, the cervix and uterus is grasped in the hand so that the hand lies over the tract with the palm down and the thumb underneath the tract. The external bifurcation can be identified as the point where the two uterine horns branch from the uterine body. The two horns should be roughly the same size although this will not be the case during late pregnancy and the early postpartum period. The uterine horns can very greatly in size depending upon the reproductive status of the animal. At estrus, the horns tend to be in a turgid, muscular state. Acyclic and sterile animals will often have a very small or nearly- infantile reproductive tract. After calving, the uterine horns will be very large, with one uterine horn larger than the other and with the reproductive tract displaced into the abdominal cavity.
4) The ovaries are either tucked slightly underneath the uterus or located to the side of the uterus at a variable distance. Sometimes, the ovaries can be found by grasping the uterus, and then, after release of the uterus, turning the hands counterclockwise while using the fingers to probe for the ovary.
4) Once located, the ovary can be grasped with the fingers while the ovary is held in the palm. The fingers can be moved along the entire surface of the ovary - periodic pressure is applied by the fingertips to search for ovarian structures. Follicles appear as pliable, fluid-filled structures. Care must be taken to avoid rupturing preovulatory follicles. Corpora lutea appear as hard structures that often protrude from the edge of the ovary. Sometimes, the ovulation fossa can be identified as a protruberance from the surface of the corpus luteum.
5) The oviducts are usually not found during palpation unless some pathology is present (i.e., oviductal inclusion or infection).
© P.J. Hansen, 1999-2005
this site was created 1999 and was last updated 5-26-2005
Cow image on top from moocow.com
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