Bovine Caslicks 

Keywords: tear, calving, injury, vulva, bovine, surgery, Caslicks

Caslicks operations (vulvoplasty) are usually perfumed on cows as a result of calving injuries. In unusually valuable animals with excessive pelvic tilt and poor perineal conformation, Caslicks may be also performed despite the potential heritability of conformation; a situation akin to that in mares. Splanchnoptosis due to heavy genital tracts in pluriparous cows complicates decision-making in such cases.

In this case (Figure 1) the vulva lips and part of the the vestibule were torn during calving, rendering a young cow with otherwise normal conformation, at risk of genital infection. In the author's opinion, this is adequate justification for the operation in a food producing animal.

Figure 1. Caslicks closure of the torn vulva lips in a first-calf cow. Image size: 960 x 1136 px

The operation is performed in the identical manner to that in mares. However, the procedure is simplified by the fact that epidural  anesthesia is simple in cattle, obviating the need for infiltration of the vulva lips with local anesthetic

Selected references:

Dehghani, S.N. et al. 2011. Treatment of peunomovaginitis in dairy cattle by Caslick operation. Research opinions in animal and veterinary sciences. 1:349-351

Prado, T.M. et al 2016. Surgical Procedures of the Genital Organs of Cows. Vet Clin Food Anim. 32:727-752

Partially persistent hymen 

Keywords: hymen, bovine, partial, persistent, heritability

A persistent hymen in any mammal represents incomplete breakdown of the conjoined embryonic margins of ectoderm and endoderm. Apoptosis of that structure is a normal phenomenon in the formation of a patent anus and vagina. The junction of ectoderm and endoderm in the vagina occur just cranial to the urethral orifice, dividing the vagina into the vestibule and cranial vagina. The reason for incomplete breakdown is unknown. Interestingly, atresia ani, an allied phenomenon, is well known to have a heritable basis in pigs and may also be heritable in calves and some breeds of dogs. Yet, persistent hymen, is not known to be heritable in any domestic animal.

In this case, there was a partial breakdown of the hymen in a beef heifer, seen during a postmortem examination for other reasons. As expected, this animal had shown none of the typical signs of a persistent hymen seen in a heifer i.e. a distended cranial vagina with occasional signs of tenesmus as described elsewhere in LORI.

Figure 1. A partially persistent hymen in a beef heifer. In this case, the hymen (black arrow) seen on the left is merely a thin dorso-ventral band, just cranial to the external urethral orifice (green arrow). On the right, the vagina has been opened and the hymen remnant, transected. The pair of forceps indicates its earlier location. Image size: 3000 x 2165px

Note: In this image the terms “cranial vagina” and “vestibule of the vagina” are used. Some prefer to simplify these terms to “vestibule” and “vagina”; an argument that remains contentious.

Selected references:

Kılıç, N. and Sarıerler, M. (2004). Congenital ıntestinal atresia in calves: 61 Cases (1999–2003). Revue Méd Vét, 155:381-384

Vianna, M.L. et al 2005 Atresia Ani in the Dog: A Retrospective Study. JAAHA 41:317-322

The umbilical vein and arteries in a bovine fetus

Keywords: bovine, umbilical, cord, artery, liver, vein, falciform

The equine umbilical circulation is discussed elsewhere in LORI and contributes to this entry.

Normally, the major blood vessels in the amnionic portion of umbilical cord of calves i.e. two veins and two arteries (three vessels in foals) snap and close by elastic recoil at the time of birth. Together with normal clotting mechanisms, this affords complete hemostatis.

Even after birth, two umbilical veins can be discerned close to the body wall of a calf using ultrasonography. These veins then fuse after entering the abdomen and drain towards the posterior vena cava through the liver. The single intra-abdominal umbilical vein is seen in figure 1. Unlike umbilical veins, umbilical arteries are not usually visible outside the body using ultrasonography intermediately after calving.

Figure 1: Perihepatic and perivesicular structures in a late gestation bovine fetus. These structures have been emphasized by post-processing coloration. The intra-abdominal umbilical arteries shown here carry de-oxygenated blood back to the placenta and are in that sense, akin to veins. Nevertheless, these arteries, like those in the umbilical cord, have histological features that are consistent with arteries. After birth, the intra-abdominal umbilical arteries are redundant and degenerate to form the round ligaments of the bladder.  The umbilical vein degenerates to form the round ligament of the liver. The membrane between the round ligament, body wall and liver becomes the falciform ligament (< Latin falc, meaning sickle ) in the calf. Image size: 1400 x 746

The urachus of course, degenerates completely in most animals. However, on rare occasions in cattle (but commonly in humans) the urachus may persist as a thin cord or tubule between the cranial aspect on the bladder and the abdominal wall. On rare occasions these remnants may cause intestinal strangulation.

Figure 2: An interesting comparison with figure 1 is seen in this image from Diseases of cattle, sheep and Swine by the French Veterinarian Gustave Moussu (1864-1945). Book copyright dated 1906. No known copyright restrictions. Image size: 1475 x 966

As mentioned, a single umbilical vein perfuses the liver. However, another major blood vessel diverges from the umbilical vein within the liver but does not perfuse the liver. Instead, it drains directly into the posterior vena cava. This vessel is the ductus venosus. Therefore, not all of the blood from the placenta perfuses the liver to exit that organ via the hepatic veins and enter the posterior vena cava. A small proportion, perhaps 30 percent, bypasses the liver through the ductus venosus and enters the posterior vena cava. As the fetal liver matures, progressively less blood bypasses the liver through this vessel. But even after birth, small amounts of umbilical blood may bypasses the liver and flow directly into the posterior vena cava.  In general, no umbilical blood should bypass the liver by 5 to 7 days postpartum When the ductus venosus persists after birth, some blood flows directly from the portal vessels into the posterior vena cava.  Because that portal blood bypasses the liver, it is not detoxified and neither does it carry beneficial nutrients (metabolized of the liver) into the systemic circulation. This is known as a portosystemic shunt. Portosystemic shunts occur in calves but are most common in dogs. They result in poor growth and hepatic encephalopathy.

Selected references:

Baxter, G.M. et al. 1987. Persistent urachal remnant causing intestinal strangulation in a cow. J Am Vet Med Assoc. 191: 555-558.

Reimer, J.M.  et al 1988 Diagnosis and surgical correction of patent ductus venosus in a calf. J Am Vet Med Assn 193: 1539-1541

Watson, E. et al 1994. Ultrasonography of the umbilical structures in clinically normal calves. Am J Vet Res. 1994 Jun;55(6):773-80.

Technique for artificial insemination; bovine.

Keywords:  bovine, vagina, insemination, A.I., AI, technique.

Routine artificial insemination (AI) in cattle is more complex than routine AI in mares.  The common method of AI in mares usually involves non-frozen semen. A gloved hand is simply inserted into the vagina then a finger into the cervix, enabling guidance of an insemination pipette into the uterus. In cattle, semen is almost invariably frozen and must be thawed carefully then inseminated by guiding an insemination rod through the cervix using transrectal manipulation. The bovine vagina, especially in heifers, will not permit the easy entry of a gloved hand and certainly, a finger cannot be passed through the cervix of a normal non-pregnant cow or heifer.

Excellent basic guidelines on those procedures can be found in publications such as this one from the UAE. or this, from Penn State University.

The intent of this entry is to illustrate the mechanics of handling an insemination rod and the act of insemination itself. The author is indebted to Select Sires US & Canada for allowing these images to be used in LORI. Select Sires holds the copyright to all images in the entry and should be contacted regarding their use outside of this image library.

After removing most of the feces from the rectum, the gloved hand is used to grasp the cervix transrectally. Then, using paper towel, the vulva lips are cleaned briefly, and the cow's tail is deflected to one side using the arm in her rectum. The vulva lips are parted (if a helper is not available, one of  the techniques described in the text box below can be used) and the AI gun is inserted into the vestibule at an upward angle. Obviously, care must be taken not to contaminate the vagina. See figure 1. It is important to grasp the cervix and push it cranially to eliminate vaginal folds that often impede passage of the AI gun.

Figure 1. An AI gun is inserted to the level of the external cervical os. In the author's opinion, the hand shown here should advance cranially to hold the entire cervical body. Holding the entire cervix in one's hand allows it to be manipulated effectively. At this point, the author also advances the AI gun so that it can be felt against the fifth digit (small finger) in the ventral part of the cervical fornix. With the entire cervix is within one's grasp, the external cervical os is lifted and fed over the tip of the AI gun. Image size:1000 x 680

Variations: One can hold the base of the loaded insemination between one's teeth; a valuable "third hand". The paper towel that has been wrapped around the AI gun to prevent semen cold shock, is removed. Some technicians fold this paper towel, kink it and place it in the ventral vulva commisure. This opens the vulva lips and serves as a surface upon which to slide the AI gun upward and into the vagina. In any case, the vulva lips should be wiped as clean as possible; generally not repeating this action without more paper towel, as that leads to more contamination than otherwise. The author uses a different approach, pushing down slightly on the cleaned perineal body using the elbow of the arm in the rectum. This causes the vulva lips to gape while the AI gun is inserted into the vagina.

  

Figure 2. An approach where the cranial vagina is narrowed over the external cervical os to facilitate entry of the AI gun into the external cervical os. As stated above, the author uses a different to technique to locate an entry point for the AI gun. The external cervical os can also be located using an endoscope designed for this purpose. However, this does not necessarily facilitate passage of the AI gun through the cervix, often the most challenging part of AI in cattle. Image size:1000 x 680

Using either technique, after the AI gun has entered the cervical canal, the rings of the cervix are manipulated over the tip of the AI gun.  See figure 3. Note the emphasis on manipulating the cervix over the gun and not placing primary emphasis on moving the gun cranially, attempting to bypass the cervical "rings" (they are not true rings but a series of crescents). The AI gun should not be forced cranially in hopes of displacing the annular rings .

Figure 3: Manipulating the annular rings (folds) of the cervix over the AI gun as it is moved gently towards the uterine body. Image size: 800 x 554

Although it is not illustrated in this entry, it is essential to place a finger over the cranial aspect of the cervix to determine that the AI gun has emerged from the internal cervical os and lies within the uterine body. The plunger of the AI gun is then depressed, expelling semen into the uterus (see figure 4). One should ensure that the AI gun is not pulled caudally into the cervix while the plunger is depressed.

Figure 4. Depositing semen within the uterine body. Image size:1000 x 680

Clitoral stimulation in both cows and heifers immediately after insemination has been shown to increase pregnancy rates marginally in some studies but this effect (especially in heifers) is not consistent. 

Some studies show advantages to intra-cornual (in the uterine horns) insemination, others not. The situation remains unclear. For routine AI therefore, it is reasonable to suggest that semen should be deposited within the uterine body (the short section of the uterus that extends only 2 to 3 cm cranial to  the internal cervical os). On the other hand, there appear to be no detrimental effects when intra-cornual insemination is used. Therefore intra-cornual should be considered when sexed semen is used or when super-ovulation is practiced.  Passing an AI gun up the uterine horn requires different techniques to those shown here, akin to those used for embryo collection. 

Selected references:

Carvalho P.D. et al. 2013 Effects of deep-horn AI on fertilization and embryo production in superovulated cows and heifers. Theriogenology. 80:1074–1081

Ciro, M. et al . Comparison between deep intracornual artificial insemination (dIAI) and conventional artificial insemination (AI) using low concentration of spermatozoa in beef cattle. Braz. arch. biol. technol.[Internet]. 2012 June.cited 2019. 55: 371-374.

Lunstra, D.D. et al. 1983. Clitoral stimulation and the effect of age, breed, technician, and postpartum interval on pregnancy rate to artificial insemination in beef cattle. Theriogenology. 19:555-563

Momont, H. et al. 1989 Does intrauterine site of insemination in cattle really matter? Theriogenology 32:19-26

Segura, C.V.M. and Rodriguez, R.O.L. 1994. Effect of clitoral stimulation after artificial insemination on conception in Zebu-crossbred heifers in the tropics. Theriogenology 42:781-787

Freemartins; vaginal measurements

Keywords:  bovine, vagina, hymen, freemartin, straw, speculum

Freemartins are common in bovine twin pregnancies. Freemartins are also seen in buffalo, occasionally in small ruminants and rarely in other species. When the sexes differ between individuals in twin or triplet pregnancies, female calves can be expected to be freemartins in 90-97 percent of calvings.  In rare cases, a male twin may die after its chorionic blood vessels have anastomosed with those of its female co-twin and the surviving twin may be born a freemartin.

Interesting historical aspects of freemartinism:  The discovery of freemartinism was attributed to the Scottish Physician and surgeon J. Hunter in his 1779 account of the Free Martin (click to enlarge): However, the basic descriptions of the cause of freemartinism has been attributed to Tandler and Keller in 1911. (Deutsche Tierärzt Wochenschr 19:148-149) and later, apparently independently, by Lillie in 1916 (Science 43:611-613).  Incidentally, the etymology of the word Free Martin, (later hyphenated as Free-Martin and finally written as freemartin) is open to much speculation but remains unknown.

In the case of a potentially valuable heifer calf being born co-twin to a male, one may choose to perform a PCR test* for the presence of Y chromosomes in leukocytes. This service is becoming common in North America.

A side note on chimeras: Less commonly used tests to diagnose freemartinism include karyotyping.  Freemartins are not only gonadal chimeras but hemopoetic chimeras as well (other organs may also be chimeric but this has not been well studied). This explains why freemartins continue to produce a mixed population of XX and XY leukocytes into adulthood. The author relied on this test for many years until it was shown that karyotyping is not an accurate method of diagnosing freemartinism unless a very large number of metaphase spreads are examined.

When the potential value of a heifer calf born co-twin to a male is not great, the simplest test for freemartinism is to measure the length of its vagina.

Figure 1: The length of the vagina in this mature heifer was 10.5 cm. One reported range of vaginal lengths in adult freemartins was 8 to 10 cm. Normal mature heifers have vaginas that are approximately 30 cm long. This heifer was born co-twin to a male, therefore it was highly likely to be a freemartins.  Size available: 843 x 1004px

An explanation: In early bovine embryos, anastomosis occurs between the chorionic blood vessels of twins lying adjacent to one another in the uterus. See this entry and another in LORI for additional details. In all female mammals, the Mullerian (paramesonephric) system develops from the endoderm. The interface between the endoderm and the ectoderm becomes the hymen. A normal vagina is comprised of a vestibule and cranial vagina, separated by the hymen. In embryos, only the section of the tract that is cranial to the hymen i.e. the Mullerian system is affected by Mullerian inhibiting hormone (MIH). Freemartins have ovotestes that contain Sertoli cells. Those Sertoli cells produce MIH, suppressing the development of Mullerian system. This leaves the vestibule of the vagina unaffected. For that reason, the majority of freemartins have normal vestibules but the cranial vagina is not patent. Therefore the length of the vagina (essentially just the vestibule) is short. In a very small percentage of all freemartins, the Mullerian system is only slightly suppressed, leaving cervixes and vaginas of normal length. Therefore the measurement of vaginal length is not infallible. However it remains a valuable rudimentary tool for the diagnosis of freemartinism.

The vaginal length of a normal heifer calf less than 30 days old is 13 to 15 cm. In freemartin calves the same age, it is only 5 to 8 cm long. Because a vaginal speculum cannot be used on such young calves, the author uses Cassou artificial insemination sheaths (regular sheaths for bovine AI guns) to measure vaginal length. Using a calf of comparable age to the suspected freemartin, a sheath is inserted into its vagina to its cranial extent then kinked at the level of the vulva lips. The same process is performed in the suspect freemartin and the two sheaths are compared, explaining the significance of the test to the farmer. See figure 2.

Figure 2: The sheath-kink test used to measure the vaginal length of a suspect freemartin calf. In two calves both less that 30 days of age, the sheath at left shows the likely presence of a freemartin calf. Size available: 1500 x 1055px

Naturally, the presence of a persistent hymen in a normal calf can confound the sheath-kink test but less than 1 percent  of heifers (approximately 0.8 percent in one large study) will be expected to have persistent hymens. A commercial probe is available to measure the length of vaginas but at far greater cost that a couple of disposable AI sheaths.

*Diagnostic tests for freemartins (PCR for Y chromosomes)

https://www.vdl.umn.edu/node/4396

https://www.geneticvisions.net/freemartin.aspx

Selected references:

Basile, J. R. and Megale F. 1974. Developmental abnormalities of genitalia of Zebu cows in the State of Minas Gerias. Argentina Biologica e Tecnologica 17:136-150.

Esteves, A. et al 2012  Freemartinism in Cattle in Ruminants. In: Anatomy, Behavior and Diseases. Ed. Marques, R.E. Chapter 7. pp.99-120. Nova Science Publishers, Inc. ISBN: 978-1-62081-064-4

Freeman, G. 2007 Explaining the freemartin: Tandler and Keller vs. Lillie and the question of priority. J Exp Zool B Mol Dev Evol. 15: 105-112

Hunter, J. 1779. Account of the Free Martin. Transactions of the Royal Society of London, 1779

Kästli, F. and Hall, J.G. 1978 Cattle twins and freemartin diagnosis. Vet Rec.102: 80-83.

McEntee, M. 1990. Ed. Reproductive Pathology of Domestic Mammals. Academic Press. ISBN 0323138047, 9780323138048

Padula, A.M. 2005. The freemartin syndrome:an update. Anim Reprod Sci 87:93–109

Uterine torsion

Key words: uterus, torsion, bovine, accident, pregnancy

Uterine torsion is not uncommon in cows. It is seldom encountered in heifers and is also infrequent in Bos taurus var indicus cattle. The reasons for those findings are not clear but have been related to large, deep and expansive abdomens in affected breeds and parity. Uterine torsion is also more common in unfit dairy cows kept in barns than those at pasture; perhaps a consequence of poor abdominal muscle tone and weak limbs allowing sudden jerky movements.  Not surprisingly, uterine torsion has also been related to poor uterine tone and hypocalcemia.

One only has to appreciate how the hind quarters of a cow are elevated above its thorax when it rises or lies down to imagine how the stability its pendulous uterus becomes precarious in that posture.  The inherently poor stability the bovine uterus adds to this predisposition. Consider the attachment and flaccidity of the mesometrium in cattle. This allows one to easily retract and manipulate a non-pregnant bovine uterus during transrectal palpation. During pregnancy the mesometrium offers even less support as the pregnant uterus expands cranially, beyond the cranial margin of the mesometrium.

In twin pregnancies, the uterus is more evenly loaded and is a result, more stable. Not surprisingly, uterine torsion is comparatively rare in cows with twin pregnancies.

Uterine torsion occurs in all ruminants and even multiparous animals but is most common in cows and horses, especially cows. In horses, mesometrial support is far more substantial than it is in cattle. One only has to try to retract an equine uterus to appreciate that reality. Even during pregnancy, the equine uterus is more stable than a bovine uterus. Also, mares change from the lying to standing posture by raising their forequarters first, so the equine uterus seldom finds itself in a pendulous state. The cause of uterine torsion is different between the two species; in cattle, as explained, it is due to uterine instability during early parturition. In mares it appears to be related to mares rolling in pasture during mid to late gestation; perhaps as they shed their winter coats.

In this entry, all descriptions of the direction of torsion are written as if one is looking at the cow, caudal-to-cranial. In that regard, anti-clockwise torsion is more common than vice versa. The reason for this is not obvious and the author's speculation will not add to the value of this entry. In the case discussed here, torsion was in a clockwise direction.

Figure 1: The mechanism of uterine torsion in cattle. In this illustration the uterus has twisted clockwise, pulling the left mesometrial ligament (LM) over to the right, cranial to the right mesometrial ligament (RM). The arrow indicates the direction of torsion. Size available: 900 x 551px

This illustration is found elsewhere in various manifestations on the Internet. However, the original image was drawn by Dr Ronald Trengrove circa 1971. Shortly before his death in 2014, Dr Trengrove gave the author permission to use and edit his veterinary drawings.  font-weight: normal>

In rare cases, uterine torsion can occur during mid gestation but it is usually a condition associated with calving. Typically, a cow affected with uterine torsion will show cessation of calving but continuing signs of discomfort. The farmer notes the typical mucous discharge from the vulva (see figure 2) the presence of colostrum,  and obvious signs of impending  parturition. Then there is no further progress. After several hours of inactivity but persisting discomfort, a veterinarian is called.

Figure 2: A pluriparous cow with uterine torsion, several hours after the onset of calving. Note the copious clear vulva discharge and distended udder. In this case, there was no obvious distortion of the vulva lips; an occasional finding in these cases. Size available: 1149 x 1159px.

If the fetus or its membranes have entered the vagina, there may be a degree of straining.  On transrectal examination, a tight mesometrial ligament can be felt stretching across the caudal abdominal cavity. Torsion of the uterus may be palpable per rectum as a corkscrew to the left or right-hand side. On vaginal examination, torsion is usually detected, but in a few cases, the site of torsion is cranial to the cervix and vaginal torsion may be absent. If the cervix has dilated, fetal limbs may be in the vagina. Often however, uterine torsion occurs before the cervix has dilated completely. If torsion is not relieved, fetal death, putrefaction and toxemia will result.
.

Figure 3: An operator (Dr J. Spears) determining  the severity of torsion and patency of the cervix.  Perhaps obviously, the cervix was indeed patent in this case; open enough to allow the operator to place a lubrication tube and calving chains. As a result rolling (described later in this entry) was not required. Size available: 1600 x 1200px

Figure 4: This image shows two obstetrical chains and a Cornell detorsion rod about to be used to rotate the calf in a clockwise direction. Size available: 1175 x 1172px

Figure 5: In this case the operator has elected to use a Cornell detorsion rod to rotate the fetus. The two red arrows in the inset image show how the calves legs are placed through loops of the calving chains prior to detorsion. The inset shows how a single chain can be use with the detorsion rod. In this case however, the operator chose to use two chains with the detorsion rod. Size available: 2203 x 1556px

A plastic device named "Gyn-Stick", similar to the Cornell detorsion rod, is available from Jorgensen labs.  It is made from rigid plastic and uses calving ropes in place of chains. Its use is shown in this commercial video.

The author was introduced to  the Cammerer's detorsion fork as an undergraduate in 1972. It is shown in figure 5, a diagram by the author. The commercial product can be seen on this website, still commercially available. In the author's opinion it is preferable to Cornell-style instruments because large cuffs spread the torsion load on the limbs and the fork enlarges the radius of rotation compared to other detorsion instruments.

Figure 5: A Cammerer's* detorsion fork' often referred as a torsion fork. Size available: 624 x 1132px

Figure 6: After successful detorsion, the cervix of the cow was dilated manually over a period of 15 to 20 minutes prior to extraction and the calf. The obstetrics chains were moved distally from their original positions on the left and right proximal radius and ulna; they were placed on conventional traction sites, above each fetlock joint. As is usually the case, the chains were also thrown into a half hitch proximal to each pastern joint.  Size available: 1409 x 1119px

Figure 7: Torsion was then used to rotate the calf by 110 to120 degrees into a dorso-left-ilial position to prevent hiplock; a normal part of mutation and traction in any assisted calving. Size available: 1600 x 1200px

Figure 8: The calf was dead in this case probably because torsion was protracted and severe. In one large study (Klaus-Halla, D. et al. 2018) 35 percent of calves were delivered live if the case was treated within 12 hours after the onset of calving and approximately 90% if treatment began within 6 hours. Size available: 942 x 1461px

In some cases the cervix has not yet dilated at the time of presentation or the uterus has twisted to such an extent as to preclude entry by the operator. In those cases, the cow must be rolled to relieve torsion. After torsion is relieved, it is possible to determine if the cervix and body of the uterus can be accessed to deliver the calf. Fortunately, in the majority of cases, the cervix will have dilated enough to permit per vagina mutation.

In the opinion of some, if cervical dilation is insufficient to allow per vagina delivery after rolling, one should wait for at least three hours for this to occur. However, the cervix may never dilate sufficiently in some cases and even if the cervix does dilate, a second visit to the farm will be required at extra cost; only to deliver a dead calf. In the author's opinion therefore, it is preferable to perform a Cesarean section immediately after rolling in those cases.

Even if the cervix is closed and it appears impossible to deliver the calf per vagina, the cow should be rolled to correct torsion. This will facilitate Cesarean section if it is required. In the event that a Cesarean is attempted before torsion is corrected, the uterus, once freed of the weight of the calf, may contract and rotate away from the surgeon. This makes the uterine wall difficult to suture.

A highly experienced colleague responded to this statement by saying that his standard approach to torsion is to perform a cesarean section immediately in all cases of torsion.

The technique of "rolling" is shown in figure 9.

Figure 9: Correction of uterine torsion by rolling (Schaffers’* method). The uterus has twisted clockwise in this case. This is shown by the inner, circular red arrow “a”. An attempt is made to roll the cow in the same direction (large red arrow) as the uterus has twisted so that the cow twists around her own uterus. A plank is often used to facilitate this process with pressure applied to the cow's abdomen, just cranial to her udder. During rolling, pressure on the uterus helps to prevent rotation of the twisted uterine horn. Although the affected uterine does not rotate during rolling, it could be said that it rotates anticlockwise relative to the cow. In this case that would be in the direction shown by the circular green arrow “b”.  If  rolling successful, fetal fluids usually escape from the cow's vulva lips immediately after torsion is relieved. An attempt should then be made to mutate and extract the calf. Size available: 1200 x 894px

*The author has been unable to determine the exact origin of the eponym Cammerer  Any assistance in that regard will be appreciated. Schaffer published on his plank modification for uterine torsion in 1946 (see references). 

Selected references:

Frazer, G.S. 1996. Bovine uterine torsion: 164 hospital referral cases. Theriogenology. 46:739-758

Klaus-Halla, D. et al. 2018 In German. Translated: [Uterine torsion in cattle: Treatment, risk of injury for the cow and prognosis for the calf] Tierarztliche Praxis. 46:143-148 

Lyons N et al. 2013. Clinical forum: Bovine uterine torsion. Livestock. 18: 18-24

Pascale, A. et al 2008. A study of 55 field cases of uterine torsion in dairy cattle. Can Vet J. 49:366–372

Roberts. S.J. Veterinary obstetrics and genital diseases (Theriogenology). Published by the author. Uterine torsion. pp 230-233

Roelofsen, J.M.P. 2018 Uterine Torsion in relation to blood calcium concentration in dairy cattle. Masters Thesis University of Utrecht.

Schaffer W. 1946. Schweizer Arch. Tierheilk 88: 44.

Uterine endometrial fissures

Key words: bovine, endometrium, fissures, uterus, postpartum, pyometra

The opened uterus shown below (image 1) was obtained from a seven-year-old Holstein cow in poor body condition. She was euthanized and submitted for postmortem examination because of infertility and continual loss of weight. Her history of postpartum estrous cycles was unknown.

Image 1, size available: 2005 x 1350 px

Apart from mild subacute suppurative broncopneumonia, the most noticeable feature in this cow was her moderately enlarged uterus, especially the right uterine horn. The uterus was turgid and distended with a large volume (perhaps 2 liters) of cloudy, tan colored, watery pus. The cervix was closed, not allowing any passage of the purulent material into the vagina. 

It is possible that pyometra had been supported by a corpus luteum (CL) formed from a postpartum ovulation (the common situation in pyometra) because a corpus albicans (CA) was present in her left ovary. However, the CA formed from the regression the CL of pregnancy can persist for extended periods after calving so that possibility is questionable. Therefore and most likely, one is left with the remarkable situation where the cervix was closed as is the case in common pyometra, yet there was an absence of luteal tissue to support that condition. More remarkable however, were the multifocal deep fissure-like ulcerations on the endometrium (image 2). These are shown, partially covered by purulent exudate in the right half of the image above. The largest of these measured 2 cm at its widest point. 

Image 2, size available: 3005 x 1773px

As indicated by the yellow arrows in the image above, the fissures were visible from the peritoneal surface as well. The serosal surface of the uterus was covered with a fine layer of yellowish fibrin indication an extension to local peritonitis.

Histopathology showed multiple small abscesses within these fissures. Neutrophils were the predominant cell type, accompanied by a low population of mononuclear cells. Culture of the uterine exudate produced no microbial growth; not particularly rare in a purulent environment.

Fissures such as these are not characteristic of common cases of pyometra due to Trueperella pyogenes (formally assigned successively to the the genera Corynebacterium, Actinomyces, then Arcanobacter). Despite an interest in reproductive pathology spanning many years, this author is unaware of similar cases and solicits the input of colleagues in this regard. Certainly, partial circumferential-splitting of the endometrium is a feature usually not seen in pyometra, even in uteruses distended with large volumes of pus.

Late gestation pregnancy and placentation

Keywords: bovine, calving, partus, parturition, placenta, caruncles, placentomes, cotyledons, cervix

These images show some of the characteristics of a pregnant uterus removed from a Simmental cow that died suddenly during the early stages of calving. The cause of death was not determined.

As shown below, the calf was located in the right uterine horn. In that regard, it well to remind readers that the uterine horn occupied by the fetus is of little significance during cesarean sections. This is because the so called "non-pregnant" horn contains such a small volume of fetal fluid that it is deflected towards the midline by the horn that contains the calf. Therefore (in a normal pregnancy) albeit left or right, the "pregnant" horn is readily accessible from a normal left flank approach.

Image size: 2888 x 1585 px 

In the image above, arrow A indicates that if one were to raise the right uterine horn and inspect the mesometrium (arrow B) the uterine artery would be visible. From about 4 months of gestation, the volume of blood flow in this artery excedes the ability of its thin wall to constrain blood flow in a linear fashion. In bovine pregnancies, this results in turbulent blood flow, reminiscent of air flowing through a "wind sock". In this video, the author illustrates turbulent air flow that is akin to blood flow vibration felt during palpation. This phenomenon is known as fremitus (< Latin. "To murmur"). Fremitus appears later in the vessel supplying the "non-pregnant" horn than that supplying the "pregnant" horn. In both vessels however, it ceases shortly after calving. Therefore it can still be present after calving and in the strictest sense, cannot be regarded as an infallible indicator of pregnancy.

Interestingly, fremitus is not detectable in pregnant mares.

As shown below, the corpus luteum (CL) of pregnancy (ringed in green) was still present in this specimen, shortly before calving would have occurred. This is normal.

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Although the CL of pregnancy is still present at term, most cows remain pregnant even if total ovariectomies are performed within the last 30 days of gestation. Indeed, some cows becomes independent of CL progesterone secretion as early as 6 months of gestation. After ovariectomy however, pregnancies do not end normally. Although pregnancies are maintained to term, cervical dilation, dystocia and retained fetal membranes are common. This is because the corpus luteum is a also a source of relaxin, prostaglandins E1 & E2 and even oxytocin. It is therefore, essential for normal parturition.

Soon (12 to 16 hours) after substantial uterine contractions begin, the cervix relaxes rapidly. This relaxation is largely under the effect of PGE2 but as mentioned earlier, other hormones are also involved.

The initial phase of cervical dilation is largely passive i.e. independent of the dividing force of the fetal head and forelimbs. However, the effect of the fetus can not be excluded completely because the uterus is pushing it towards the cervix, even during the early stages of cervical dilation. Within 8 to 10 hours in cows and somewhat longer in heifers, the cervical canal dilates to a diameter of 12 to 20 centimeters i.e.

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In the specimen discussed here, passive dilation was incomplete yet almost sufficient to accommodate a human hand (about 12 cm wide, including the thumb).

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Normally, in pre-term pregnant cows, even in autolysed specimens, this would be impossible. Therefore had this cow lived, the second (expulsive) stage of calving would have been imminent.

The image below confirms the fact that the fetus had not yet entered the birth canal i.e. active dilation of the cervix and second stage parturition had not yet begun.

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The following image shows the fetal membranes and the calf, removed from the uterus.  The normal number of placentomes in bovine pregnancies varies between 75 and 120, the largest measuring 12 to 14 cm in length. Also, as reviewed elsewhere, amnionic fluid volume varies between 2 and 8 liters and allantoic fluid, between 4 and 15 liters. This pregnancy appeared to be normal in those respects.

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Placentation in ruminants consists of numerous complexes. Hence the term "multiplex placentation" as apposed to "diffuse, discoidal, zonary" etc.  The two parts of each complex are of course, a caruncle on the maternal side and a cotyledon on the fetal side. Together, they form a placentome. A placentome is shown here:

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As illustrated elsewhere in LORI, the site and number of caruncles in a cow has already been established when the cow herself was a fetus!

Note how the fetal villi are sliding out of the maternal crypts, a process that is impossible if  placental maturation (flattening of maternal epithelium and loosening of fetal-maternal contact) has not occurred during the last few days of gestation. Incomplete placental maturation is a cause of retained placenta. Placental maturation is impaired if the fetus is born prematurely or the diet of the cow is deficient in selenium and vitamin A, nutrients that are essential for epithelial function. This explains in part why retained placenta is common when selenium and vitamin A are deficient in the diet of pregnant cattle.

Fetal ascites & anasarca (hydrops fetalis)

Keywords: bovine, anasarca, ascites, dystocia, heritable, neoplasia, hypoplasia, IVF, clone, cloning

Ascites: < Greek askos; "a bag of wine"
Anasarca: < ana : "throughout" & sarca: "new flesh"
Hydrops fetalis: Abnormal accumulation of fluid in two or more fetal compartments, including ascites, pleural effusion, pericardial effusion, and skin edema.

A complex subject with varying appearances and many different etiologies. Hydrops fetalis (HF) may be due to any factor/s that cause passive venous congestion i.e. intra-peritoneal or intra-thoracic neoplasia (leiomyomas, teratomas hepatoblastomas), liver cirrhosis or other liver anomalies, cardiac anomalies, pulmonic valve stenosis or dysplasia of the lungs themselves. Some of these anomalies are heritable in several breeds of cattle. As is so often the situation with abnormal calves, the calf shown below (photographed 41 years ago!) was discarded without a thorough post mortem examination. Therefore the cause of ascites in this case was unknown.

Because of its enlarged abdomen and resulting dystocia, the calf (weighing 71 kg) was delivered by cesarean. A calf with ascites can often be delivered per vagina after incising its abdomen using a finger knife and allowing the fluid to drain into the cow's uterus. The yellow staining  of the hair coat here was due to meconium discharge from the anus; a common situation during fetal distress precipitated by hypoxia.

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In the fetus below (delivered by cesarean and also discarded without a thorough postmortem examination) there was ascites as well as marked anasarca. The calf showed a multitude of musculo-skeletal deformities too.

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In fetuses produced by assisted reproductive technology (ART) i.e. cloning through nuclear transfer (NT) and in vitro fertilization (IVF), pregnancy failure is common and many abnormalities have been described in calves, lambs and human babies produced through ART. The most striking of these is the so called "Large offspring syndrome" where newborn babies, calves and lambs can be several times their normal weight at birth. Cardiac, kidney, hepatic and pulmonary abnormalities have been described in these cases. In addition, angiogenesis itself can be abnormal, leading to increased permeability of blood vessels in the fetus and fetal membranes.

In the case shown below, the calf was a product of IVF and abortion occurred at 7 months of gestation. There was severe ascites and anasarca (HF) as well as hydrops amnion and allantois. The case is discussed in more detail in another LORI entry, featuring a video. In that video, the author suggests that genetic alterations may occur in these cases as a result of culture conditions. However, current information shows that the abnormalities manifested in cases of IVF and NT are largely epigenetic in nature.

The calf weight 56Kg; well in excess of the 8 to 18Kg range for a fetus of this gestational age. Meconium staining of the hair coat is obvious in this case as well.

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Pitting edema (below) was present over the entire surface of the calf and its fetal membranes.

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Subcutaneous edema is visible here, in the upper left inset. At lower right, a stream of ascitic fluid  is being released from the abdomen. Readers are encouraged to view the teaching video mentioned above to appreciate the nuances of this case.

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In conclusion, ascites, anasarca, placental edema, hydrops allantois and hydrops amnion are common manifestations of  various conditions that may or may nor be related to one another.

Selected references:

Alberto, M.L.V. et al. 2012. Development of bovine embryos derived from reproductive techniques, Reproduction, Fertility and Development. 25: 907-917

Baraya, Y.S. et al. 2015. Dystocia associated with foetal anasarca (hydrops fetalis) in a Nigerian breed of sheep; Case report. Proceedings: Sixth Pan Commonwealth Vet.Conf.of the CVA and 27th Vet. Assn. Malasia Conf. 519-522

Buchanan, J.W. 2001. Pathogenesis of single right coronary artery and pulmonic stenosis in English Bulldogs. J. Vet. Intern. Med. 15: 101-104

Chen, Z et al. 2013. Large offspring syndrome. A bovine model for the human loss-of-imprinting overgrowth syndrome Beckwith-Wiedemann. Epigenetics 8:591–601

De Vries, C. et al 2012. Congenital ascites due to hepatoblastoma with extensive peritoneal implantation metastases in a premature equine fetus. J. Comp. Path. 2012, 148: 69-69

Drost, M. 2007. Complications during gestation in the cow. Theriogenology. 68: 487-491

Edwards, J.L. et al. 2003. Cloning adult farm animals: A review of the possibilities and problems associated with somatic cell nuclear transfer. A. J. Reprod. Immunology. 50: 113-123

Golladay, E.S. and Mollit, D.L. 1984. Surgically correctable fetal hydrops. J.Pediatric Surgery.19: 59-62

Pinborg, A. et al. 2014. Large baby syndrome in singletons born after frozen embryo transfer (FET): is it due to maternal factors or the cryotechnique? Hum. Reprod. 9: 618-27

Pushp, M.K. et al. 2016. Dystocia in a non-descript cow due to ascetic fetus- a case report. J. Livestock Sci 7: 62-64

Rheuban, K.S. et al. 1991. Intrapericardial teratoma causing nonimmune hydrops fetalis and pericardial tamponade: A case report. Pediatric Cardiology. 12: 54–56

Roberts, S.J. 1986. Veterinary obstetrics and genital diseases. Diagnosis and treatment of various types of dystocia. pp 333-335. Published by the author, S.J. Roberts.

Sasaki S. et al. 2016. A missense mutation in solute carrier family 12, member 1 (SLC12A1) causes hydrallantois in Japanese Black cattle BMC Genomics 17:724 739

Svara, T. et al. 2016. Pulmonary hypoplasia and anasarca syndrome in Cika cattle. Acta Vet. Scand. 58: 36-40

Testoni, S.et al. 2009. Congenital facial deformities, ascites and hepatic fibrosis in Romagnola calves. Vet.Rec. 164: 693-694

Walker, S.K. et al. 1996. The production of unusually large offspring following embryo manipulation; concepts and challenges. Theriogenology 45: 11l-120 

Whitlock, B.K. et al. 2008. Heritable bovine fetal abnormalities. Theriogenology. 70: 535-549

Windsor, P.A. et al. 2006. Hydrops fetalis associated with pulmonary hypoplasia in Dexter calves.

Australian Vet. J. 84: 278-281

Young, L.E. et al. 1998. Large offspring syndrome in cattle and sheep. Reviews of reproduction. 3: 155-163

Breeding soundness evaluation

Keywords: bull, bovine, BSE, ejaculation, EEJ, penis, semen, scrotal, tape, circumference

Several of these images appear in a video on breeding soundness evaluation in ruminants; the bull, ram and buck. In addition to other images, they are presented here for your use. As usual, right clicking on an image and selecting "save as" will allow one to see and save an image at full resolution.

One may choose to skip the accompanying text altogether. For some however, it will serve to put the images into context. 

An Australian colleague notes that the term Breeding fitness examination (BFE) is used in preference to Breeding soundness examination (BSE) in Australasia. No convincing argument is given for that nomenclature therefore it is unlikely the the term BFE will ever be adopted in North America. However, being respectful of Australian views, terms such as "boomerang" and "kangaroo" will be retained for use in both the US and Canada.

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Bulls should be evaluated for breeding soundness before purchase and routinely, before each breeding season. A BSE is also performed if a bull is suspected of being infertile.

Although a bull may have normal genitalia and semen, he is useless if skeletal, muscular, foot or eye pathology prevent him from breeding. For this reason, a general physical examination is essential. This concept is illustrated below:

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Obvious predispositions to problems such as preputial prolapse (below) and undesirable scrotal shape should be pointed out to owners.

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Because of more efficient heat loss, a pendulous scrotum is preferred over a straight-sided or wedge-shaped  scrotum that holds the testes close to the body. Scrotal shape should be evaluated with the testes fully descended in the scrotum.

Defects such as scrotal shape and pendulous, prolapsing prepuces are generally not used in evaluations to fail bulls. Instead they justify which bulls are preferred over others as potential herd sires.

Routine tests for venereal diseases such as Campylobacterosis, Trichomoniasis or even systemic problems such as persistent shedding of BVD, are generally not part of a routine BSE but may be where these diseases are of concern.

Before semen collection can commence, transrectal examination of the accessory glands and internal inguinal openings must be performed. This is shown below.

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The scrotum must be palpated thoroughly for normal tone and resilience as well as any evidence of orchitis, neoplasia, epididymitis and inguinal herniation. This is especially the case when the scrotum appears to be asymmetrical or when transrectal palpation suggests that an internal inguinal ring is enlarged and may contain omentum or a loop of bowel. Trans-scrotal ultrasonography can be used to confirm the diagnoses of all these conditions.

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Three factors are used to assess the breeding potential of a bull. These are: sperm motility and morphology and scrotal circumference. Even when it is evaluated by Computer Assisted Semen Analysis (CASA), motility only has a low correlation with the fertility of a bull. Nevertheless, this correlation is statistically significant and as such, remains part of routine bovine BSE. CASA is not typically used for bovine BSE.

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The scrotal circumference of a bull is measured using the specially-designed scrotal measuring tape shown above. The scrotum of this bull had a circumference of approximately 50 cm which is large for any breed and by any standard.

Scrotal circumference in bulls is positively correlated to sperm output and negatively correlated to the age of female offspring at the time of puberty. However, scrotal circumference is dependent on the age of the animal and on the breed as well. The table below shows the minimum acceptable scrotal circumference for a bull of a given breed at a specific age.

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The image below shows the scrotal measurement of a two year old Limousin bull; unacceptably low, even for that breed (see the table above).

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Severely hypoplastic testes in a one year old Angus bull. These testes are too small to even warrant consideration of the bull as a herd sire.

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When possible, libido and mating ability are assessed by the farmer and supplied as part of the history. When these data are absent, a major flaw in routine bovine BSE becomes evident.

Semen can be collected by electrical stimulation or through the use of an artificial vagina (AV). However, AVs are usually used for frozen semen production because a bull must be trained to serve an AV and this is usually not possible for a routine BSE. Transrectal massage of the intra-pelvic section of the penis may produce ejaculates on occasion but is generally unreliable.

Electroejaculation  (EEJ)is achieved by using a large intra-rectal, lubricated probe with several electrodes that run caudal-cranial on its ventral surface. The probe is placed in the rectum and increasing rhythmic electrical stimulations are applied until erection and ejaculation occur. Stimulations usually last for 1 to 2 seconds and discontinued for about ½ second. This is continued until ejaculation occurs. Modern systems are programmed for optimal stimulation,

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The voltage applied is very low. In fact, an intrarectal probe can easily be held in the hand while applying maximum stimulation. However, the ionic environment of the rectum and the proximity of the stimulus to the pelvic nerves are sufficient to cause erection and ejaculation.

EEJ causes muscular activity in the hind quarters, occasionally vocalization and probably a degree of discomfort as well. For that reason, it is considered to be inhumane and is prohibited in some countries. However, this author believes that EEJ can be humane when used properly. EEJ, it effects and alternatives are well reviewed in the selected references given below.

It is essential to support the bull with a chest band during EEJ (see the yellow arrow below) so that he does not collapse in the crush if excessive muscle contraction occurs. In the author's hands it has often been possible to obtain semen samples with minimal muscle contraction. If the bull vocalizes, the author usually ceases stimulation immediately. Occasionally it is not possible to obtain a sample via EEJ.

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During transrectal palpation and by massaging the intra-pelvic section of the penis, one can often induce pulsation and partial erection. Once the penis is extended, it can be grasped using a piece of gauze to avoid slippage (inset at upper right in the image above). This allows the operator to inspect the penis closely before proceeding with semen collection. If massage does not induce partial erection, slight stimulation with the electroejaculator may be used for that purpose. On occasion, the penis cannot be exposed or examined and ejaculation occurs within the preputial cavity.

Semen samples obtained by EEJ (inset at lower right in the image above) are of equal fertility to those obtained with an AV but the volume of the ejaculate is usually higher and the concentration lower, than samples obtained with an AV.

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The image above shows equipment used for routine BSE. The paperwork is necessary for documentation of  the BSE. The special scrotal circumference measuring tape is that shown in earlier images. The two short black tubes hold clear plastic cones, connected to test tubes for semen collection. Note that these devices have long handles on them so that one does not have to reach in under the bull during collection; avoiding possible injury by kicking. Two or more collection vessels should always be available in case the first vessel becomes contaminated with urine. If this occurs, one can switch collection immediately to the second vessel. 

A sleeve for rectal palpation is seen under the collection vessels. This is used to perform transrectal palpation. .

The motility of the semen is evaluated subjectively immediately after collection. The sample must be kept at 35° to 37° C on a warming surface until it is examined. Any slides and cover slips must be warmed to the same temperature, 

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Microscopic examination of a drop of semen placed on a slide under low power will reveal wave motion if the motility is normal and sperm concentration is high.

In a normal samples one expects at least 60% of spermatozoa to exhibit progressive motility. Other spermatozoa are either immobile or exhibit bizarre motility such as oscillatory, vibrating or rotating motion. If the density of the semen is high, it can be diluted with 2.9% Na citrate or saline to observe the motility of individual spermatozoa. An alternative is to trap sperm within a bubble under a cover slip. This will also allow observation of the motility of individual spermatozoa. (video - pending insertion)

For critical evaluation of motility, phase contrast microscopy is useful. In addition, sperm smears should be stained with modified Blom's or a Diff-Quik stain and examined using regular microscopy. These smears should be stored as a part of the bull's permanent record. Good quality optics are essential and only high-power magnification (1000 to 1250 x) should be used to examine the morphology. At least 200-300 sperm cells should be examined in each sample.

Semen should be free of blood, inflammatory cells, foreign materials and cells from the germinal epithelium. These are referred to as Cells other than sperm  or COTS. Abnormalities are described on the BSE record. See inset at lower left in the image above.

In the ejaculate shown below, the sample was highly contaminated by COTS, due to an abrasion on the penis that hemorrhaged when the penis became erect.

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One should bear in mind that motility can easily be reduced by urine and blood contamination, cooling or improper handling procedures. Motility is also somewhat dependent upon morphology, because abnormalities of the tails of sperm cells will reduce their motility.

In some cases, sperm cell motility may improve with subsequent ejaculations, especially if the bull has not been used for some time.

Sperm deformities such as bent tails, midpiece droplets, expanded midpieces, loose acrosomes and misshapen heads are often encountered.  Abaxial attachments are considered normal in some species where they occur in large numbers in fertile males (boars for example) but their significance in bulls remains debatable. In low numbers, the significance of abnormal spermatozoa is questionable. In normal ejaculates, 60 to 70% of the spermatozoa show no abnormalities. In the image below, normal sperm are shown in the left inset image. In the right inset image, numerous sperm have abnormal morphology, their presence indicated by arrows.

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The image below shows the exquisite morphologic detail revealed by Nomarski, interference contrast. This tool is not use routinely for BSE but should be considered in cases of special interest.

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When potentially heritable defects such as this Dag-like defect (named for a renowned Danish Jersey bull) are seen, tools such as scanning electron microscopy can be employed to study the condition and report on its presence to a breed society. Even further transmission EM study may be needed to confirm the diagnosis of certain conditions. It should be emphasized that such investigations are not commonly performed.

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Bulls are usually classified as satisfactory, questionable or unsatisfactory potential breeders, or have their classifications deferred. Note the use of the word potential, i.e. a bull may appear normal in all respects but may still be infertile due to abnormalities of the spermatozoa that cannot be appreciated on routine examination. One can never guarantee the fertility of a bull. Also, it should also be borne in mind that the judgment of the breeding potential for any particular bull is valid only on the date of examination.

When indicated, bulls can be re-evaluated at a later date. The time required for spermatogenesis in bulls is about 60 days. Another 11 days should be allowed for sperm transport through the epididymis. These figures should be taken into account when one recommends re-evaluation.

BSE forms can be obtained from the Society for Theriogenology (SFT) and the Western Canadian Association of Bovine Practitioners (WCBP). They are similar in content. Both the SFT and WCBP offer software for recording and retrieving BSE results. These programs also allow one to print BSE results for clients and accumulate valuable data for research.

Selected references:

Palmer, C. 2005. Welfare aspects of theriogenology: Investigating alternatives to electroejaculation of bulls. Theriogenology. 64: 469–479

Whitlock, B.K. et al. 2012 Electroejaculation increased vocalization and plasma concentrations of cortisol and progesterone,  but not substance P, in beef bulls. Theriogenology. 78: 737–746