Normal lochia from a dairy cow

Keywords: lochia, postpartum, bovine, cow, involution, uterus

Image size: 1200 x 1600px

Normal lochia from a dairy cow at 12 days postpartum; seen in its bedding. At this time, the sloughing process of the caruncles reaches the capillary beds, releasing red blood cells into the lumen. Therefore this discharge is normal and in the absence of fever, inappetence and other common pathology at calving (mastitis, traumatic reticulo-pericarditis etc) it requires no treatment.

Ovary of a three month calf

Keywords: ovary, bovine, AMH, primary, primordial, follicle, puberty

Image size: 466 x 351px

A cross sections of the ovary of a three month old heifer calf showing primary follicles (a single layer of luteal cells) and secondary follicles (multiple layers of luteal cells). Note the primordial follicles containing primary oocytes. These 2n oocytes are suspended in prophase, prior to the reduction division of meiosis. Reduction to the haploid state will only occur when a selected follicle is stimulated by LH prior to ovulation.

Primordial follicles are those that have flat epithelium surrounding the basement membrane of the oocyte. When these become more cuboidal as perhaps those are here, the follicle is termed primary instead of primordial. When the granulosa (g) cells, which are all inside the basement membrane (seen best on a high power image, where it is as labeled “bm”) multiple but have not yet formed an antrum, the follicle is termed a secondary follicle. A secondary follicle is shown below.

Image size: 466 x 351px

Those with a well formed antrum are tertiary follicle; there are none in this image because they only form at the approach of puberty.  Outside of the basement membrane, cells from the stroma (s) accumulate and form the theca of the follicle. These follicles are too young to show the theca but it is obvious in tertiary follicles. The theca externa is fibrous in nature but he theca interna is glandular, producing androgens which are aromatized to estrogens by the granulosa cells.

The zona pellucida is already present in primary follicles but is best seen here in a secondary follicle on a high power image, where it is as labeled “zp”

Pre antral follicles like these form anti-müllerian hormone (AMH) which prevents them from binding FSH and being recruited prematurely and en mass. AMH measurements are valuable as an indicator of the number of these pre-antral follicles and hence, the potential value of the heifer as an embryo donor.

Sensitive periods for Ovsynch treatment

Keywords: cow, synchronize, bovine, estrous, estrus, cycle, follicle, wave, Ovsynch

A diagram modified from several sources, showing an estrous cycle with three follicle waves. The physiology of two or three follicle waves is important during “Ovsych” treatment (GnRH-Prostaglandin-GnRH) because it is only those follicles that have already been recruited and already growing in a follicle wave that will ovulated after GnRH treatment; an essential step in re-setting the recruitment of follicles so that a mature follicle will be available for ovulation about 8 to 9 days later. This image shows the periods of time (vertical grey bars) during which follicles can be induced to ovulate by GnRH treatment.

Two and three wave estrous cycles

Key words: bovine, estrous, estrus, cycle, follicle, wave, Ovsynch, prostaglandin

A diagram modified from several sources of two and three wave estrous cycles. One cow has two waves of follicle growth with the follicle in the second wave eventually ovulating. The other has three waves, with the last wave providing the follicle that ovulates. The length of the estrous cycle is one or two days longer in cows that have three follicle waves instead of two. A minority of cows have four follicle-wave estrous cycles.

This physiology is important in everyday dairy practice when prostaglandins are used to shorten the inter-estrous period because follicles are more likely to large and ready to ovulate if cows have more follicle waves during the estrous cycle. There is usually only one follicle per wave but once a follicle has grown to its maximum size it begins to regress, it cannot be utilized. Therefore, many follicles and their oocytes are wasted. The physiology of two or three follicle waves is also important during “Ov-sych” treatment to synchronize ovulation in cattle.

Bovine uterine involution

Key words: bovine, involution, uterus, cycling, estrous, cycles, postpartum, palpation

The uterus of a cow, two weeks after calving, opened to show the state of involution. At this stage of involution, the areas of the endometrium have already involuted (this occurs by about 10 days after calving) but the caruncles themselves have not even sloughed their epithelium completely. It is only by 12 to 14 days that (at about the stage the uterus in this image) that the sloughing process reaches the capillary beds, releasing red blood cells into the lumen. It also at this time, that neutrophils enter the lumen, attracted by chemotaxis to the contaminated lochia. Therefore lochia that are somewhat purulent and blood tinged at this time are normal.

The contents of the uterus are normally contaminated (not infected) by bacteria up until 25 to 30 days postpartum. The bacterial swab in the inset has been added as a reminder to this fact. Uterine cultures taken before this time being of limited value.

Image size: 1229 x 1162px

During transrectal palpation, it only possible to grasp the cranial border of the uterus by about this stage of involution i.e. 10 to 14 days after calving; much later than in mares. The size of an average human hand is given to scale to allow one to appreciate that challenge. Depending on management and health of  animal it has returned to its pre-pregnancy size by about 35 days after calving; in some reports as early as 25 days; in others, as late as 50 days. It is easily retracted at that time. After calving, the uterus of a cow is always larger than that of a heifer.

Although the corpus luteum of pregnancy is visible for several weeks after parturition (see the inset at right above) it has ceased to function at the time of calving.

Uterine involution is for all practical purposes, disconnected from ovarian function in cattle. It is also disconnected from estrous behavior. In dairy cows (where human interference prevents calves from suckling) the first ovulations after calving often occur before 20 days postpartum but those ovulations are seldom accompanied by signs of estrus. Over the next two to three ovulations (which occur at increasing intervals between one another) estrous display becomes more obvious. Interestingly, the process of uterine involution is slower than both the resumption of normal ovarian activity and estrous display.

Although the epithelial regeneration over the caruncles is largely complete by 30 to 35 days postpartum, global involution of the uterus continues over the next 10 to 15 days. Certainly, the uterus is completely involuted by 70 to 75 days, when the first inseminations start occur after calving in most dairy cattle i.e. the "voluntary waiting period". In beef animals, where suckling occurs, and breed and energy intake can also have profound negative effects on postpartum anestrous intervals, uterine involution is complete long before re-breeding occurs and is seldom a limiting factor in postpartum fertility.

Note of interest: Although the complex physiology of postpartum anestrus (nutrition, breed, presence of milk in the udder, calf contact etc) is still not completely understood, one of the cornerstones of anestrus appears to be a lack of LH secretion. Strangely, FSH secretion is a not a limiting factor in the resumption of cyclicity, well developed follicle populations being plentiful well before the first ovulations occur. A major negative effect on LH secretion is that of endogenous opioids (endorphins). This is not only true for cattle in the postpartum period but for mammals in general, including humans. LH secretion increases almost immediately after morphine antagonists such as naloxone and naltrexone are administered.

Postpartum corpus luteum in a cow

Keywords: cow, bovine, postpartum, ovary, corpus luteum, CL

Image size: 1044 x 778px

Corpora lutea (CLs) in the ovary of a cow approximately one week after she had given birth to twins. The cow was euthanized because she had injured herself during calving. This image shows that corpora luteal are still present within the ovary for at least a week after calving; this despite the fact that they are not required for the maintenance of pregnancy for the last four months of gestation. These corpora lutea would have been producing little if any progesterone. In fact, cows can be ovariectomized after the first month of gestation and will maintain pregnancy and can calve normally. Therefore, the role of the ovaries (and corpora luteal in this case) during late gestation cattle is uncertain.

The cervix of a postpartum cow

Keywords: cervix, involution, bovine, cow, endometrium, lochia

Image size: 868 x 707px

The cervix of a cow seen at approximately one week after calving. This animal was euthanized because of a skeletal injury sustained during the birth of twin calves. Minor contusion and lacerations such as those seen here are common after parturition.

The bovine cervix closes down fairly rapidly after calving so that at this time (about a week after calving) it is difficult to introduce a hand into the uterus. However, the cervix remains open for at least 20 days to allow the discharge of lochia. This lochia becomes hemorrhagic at about 10 to 12 days when the remnants of the caruncles of pregnancy are sloughed to the level of the endometrial capilliary beds. It is also at about this time that the lochia begin to become purulent in nature as neutrophils enter the lumen from the capilliary beds. Therefore, if this photograph had been taken a few days later, it would not be unusual to find a hemorrhagic and somewhat purulent discharge being voided through the cervix.

Follicle and a corpus luteum; ultrasound

Key words: wave, bovine, CL, corpus luteum, follicle, cow, ultrasound

Image size: 640 x 480px

A large follicle (the non-echogenic structure) adjacent to a corpus luteum (CL) in the ovary of a cow; as seen during transrectal ultrasonography. Follicles grow and regress in waves during the bovine estrous cycle. There are commonly two or three waves of follicle growth during the diestrous period. When there are three waves, the estrous cycle is longer (21 to 22 days) then when they are two follicle waves (19 to 20 days). Less commonly,  cows may even have four follicle waves. Therefore the discovery of a large follicle during diestrus (as in this case) does not necessarily mean that a cow is approaching estrus.

Sexing the bovine fetus.

Keywords: sexing, bovine, ultrasound, male, female, ultrasonography

Image size: 640 x 480px

A female bovine features seen via transrectal ultrasonography at approximately 60 days of gestation. It is commonly states that the genital tubercle is used to determine gender in such cases. In this case for example, a caption could read: "The two highly echogenic spots visible between the hind legs, close to the tail show the location of the genital tubercle  (arrow) in a female fetus.  In the case of the male, the genital tubercle is seen as a bright echogenic structure just caudal to the abdominal attachment of the umbilicus."

However, the genital tubercle is not a paired structure, it develops into the clitoris in females and the penis in males. By contrast, the urogenital folds are paired structures (in both sexes) located on either side of the genital tubercle. Therefore it more likely that the paired echo seen above is being generated by the urogenital folds, not the genital tubercle.

The genital tubercle can be seen below. It is the precursor of the clitoris and  is a single, sickle-shaped structure  The urogenital ridges have almost developed into the vulva lips in this 60 day old bovine fetus (below).

Image size: 1263 x 927 px


The mammary gland (under circle) of this 60 day old fetus.

Image size: 1500  x 1125px

Although rudimentary teats are present in males, the mammary gland is well developed in females and serves as a landmark for sexing female fetuses.  It should be visible via ultrasonography between 75 and 120 days of gestation.

A follicle and a luteinized cystic follicle

Keywords: CL,corpus, luteum, cystic, bovine, cycle, infertility, cow, ultrasound

Image size: 640 x 480px

A follicle together and a luteinized cystic follicle seen by transrectal ultrasonography in a cow.

Together with its appearance, a history of postpartum anestrous allowed a diagnosis of a luteinized cystic follicle (sometimes referred to a luteal cyst) in this cow.  Cystic follicles and the luteinized structures they develop into, are abnormal structures, associated with an absence of estrous cycles in the early to late postpartum period; almost always in dairy cows. In dairy cows, abnormal estrogen secretion and abnormal LH surges are thought to be important in the syndrome. Cystic follicles are also seen in beef heifers, but usually only after the use of steroid growth promoters.

Clarification: Cystic corpora lutea are normal structures, associated with normal estrous cycles.  Most corpora lutea luteinize completely, obliterating the antrum of the ovulated follicle but many are left with small to large cysts in the center.  This author does not use the term “luteal cyst” (an abnormal structure) because it can easily be confused with the term “cystic corpus luteum” (a normal structure). Instead, the term luteinized cyst (a cystic follicle that has become luteinized) should be used.

Bovine leucosis in a pregnant uterus

Keywords: BLV, cow, bovine, leucosis, pregnant, vagina

Image size: 1672 x 1404px

Enzootic bovine leucosis is a result of infection by bovine leukemia virus (BLV). Less than 1% of all the cattle infected with this virus actually develop lymphoid sarcomas and often these are found in pregnant cows. In this case, where the cow was approximately 5 months pregnant, the vagina was affected (black arrows) as well as the myometrium (yellow and green arrows). The double ended green arrow shows a diffuse area of the myometrium thickened by a sarcoma.

Leucosis in the uterus of a cow

Keywords: bovine, COD, cystic, BLV, leucosis, uterus, bovine

Image size: 1200 x 807px

Bovine leucosis is caused by the bovine leucosis virus. Many cows are carriers and asymptomatic. In this case, as shown by the arrows, there are multiple foci of leucosis in the uterus of the cow. This cow also had a cystic CL,in the right ovary; a normal structure in many cycling cows (not to be confused with a luteinized cyst).

Leucosis in the uterus of a pregnant cow

Keywords: leucosis, bovine, neoplasia, BLV, pregnant

Image size: 1000 x 967px

Leucosis seen in the dorsal wall of the body of the uterus in a pregnant cow. This tract was obtained from a slaughter  plant specimen, so no history as available other than the cow being labeled as a "cull cow". It was estimated that this pregnancy was approximately 45 days old. It is not a usual to encounter pregnancies in cattle that are severely affected by leucosis, even when the uterus is involved.

Bovine mucometra/hydrometra

Keywords: adhesions, bovine, hydrometra, mucometra

Bilateral peri-uterine adhesions and fibrosis of the perimetrium/myometrium which appear to have caused distortion and mucometra.

Image size: 1023 X 1283 px

Dissection of the tract did not reveal a specific area of occlusion that would have resulted in this condition. It is possible that the inciting cause was fibrosis of the cervix itself. 

This condition should be referred to as mucometra because it is characterized by an accumulation of mucus; not water (hydro). It is not related to a chromosomal abnormality such as that in polled intersex goats i.e. the PIS syndrome. It is a rare condition in cattle, manifested by unilateral or bilateral distension of the uterus with clear fluid. Occasionally the fluid may contain clumps of inspissated tissue the nature of which have not been described.  In studies on slaughter plant specimens, mucometra occurred in about 0.1 to 0.8 percent of cattle.

Mucometra occurs in cattle as a result of adhesions or fibrosis (as seen here). It is also seen in cattle with segmental aplasia or in heifers with persistent hymens. Mucometra has also been linked to chronic cystic ovarian disease (COD) but is by no means, characteristic of that condition.

References:

Fathalla, M. et al 2000 An  abbatoir survey of gross reproductive abnormalities in the bovine genital tract in northern Jordan. Israel. J. Vet. Med. 55. No page numbers. Available on-line.

Roberts, S. J.1986. Veterinary obstetrics and genital diseases (Theriogenology). Published by the author.  ISBN-10: 9997670922. ISBN-13: 978-9997670922

Suspect granulosa cell tumor. Beef cow

Keywords: beef, bovine, ovary, neoplasia, tumor, GCT, granulosa, polycystic

Image size: 1617 x 1096px

A large, firm, polycystic structure replacing the ovary on the tract of a slaughter plant specimen from a beef cow. The bluish appearance of the cysts is probably true, judging by the correct color of the uterus. As for others in this collection, this image from 1980 was labeled as "Ovarian cyst - beef cow". Judging by the size of the tumor and the manner in which it has replaced the ovary, is far more likely that this is a polycystic form of a granulosa cell tumor. Granulosa cell tumors in cattle can be solid, may consist of a single large cyst or can be polycystic or as in this case.

Suspect granulosa cell tumor. Beef cow

Keywords: beef, bovine, ovary, neoplasia, tumor, GCT, granulosa.

Image size: 1042 x 691px

A large and almost spherical (the image was not re-touched in that regard) replacing the ovary on the tract of a slaughter plant specimen from a beef cow. As for others in this collection, this image from 1980 was labeled as "Ovarian cyst - beef cow". Judging by the size of the tumor and the manner in which it has replaced the ovary, is likely that this was a cystic form of a granulosa cell tumor. Granulosa cell tumors in cattle can be solid, polycystic or as in this case, may consist of a single large cyst. This is a likely diagnosis but of course, is based only on speculation.

Lymphosarcoma pyometra in a cow

Keywords: lymphosarcoma, pyometra, cow, unusual, BLV, leucosis, bovine, uterus, pus

Image size: 1182 x 1756px

An unusual form of pyometra in a cow. Usually, pyometra in cows is due to infection with Arcanobacter pyogenes during the postpartum period. In this case, pyometra was due to bovine leukosis caused by the bovine leukemia virus (BLV). Usually, cows with leucosis in the uterus have multiple nodular disseminated foci of lymphosarcoma; occasionally, large plaques of lymphosarcoma in the myometrium. In this case, there were no the typical modules of lymphosarcoma in the uterus. Instead there was a large volume of pus in the uterus, composed entirely of lymphocytes. As is usual, the cow also had disseminated leucosis nodules throughout many of its organs; the spinal canal, heart, liver etc.

Pyometra or following insemination

Keywords: Tanabe, bovine, cow, insemination, pyometra, Arcanobacter pyogenes

Pyometra that followed insemination in a cow. Pyometra usually occurs spontaneously in postpartum cow's as a result of infection with Arcanobacter pyogenes. This image is regarded as unique because it states that this case the pyometra occurred after insemination, suggesting iatrogenic contamination as a cause the condition.

An update has kindly been provided by Dr R.G. (Dick) Saacke, Professor Emeritus of Reproductive Physiology. Dept. of Dairy Science, Virginia Polytech. Inst. and State University (edited):

This image was produced by Dr. TY Tanabe at Penn State University. The image was taken after a pregnant cow was bred trans-cervically during early pregnancy. At the time, liquid semen without antibiotics was used. This resulted in the loss of pregnancy and in some cases, pyometra as seen here. As a consequence of his research, Dr Tanabe recommended that if a cow should show heat after being bred, the subsequent insemination should be no deeper than mid-cervix. He produced many images addressing the disastrous consequence of insemination at several stages of pregnancy

Dr. Tanabe has since died, but many of his excellent photographs are digitized and available through the USDA Image library. 

Author's note: Insemination of pregnant cows still occurs but it is remarkable that many of these pregnancies survive. This is either due to the addition of antibiotics or caution of technicians sensing the possibility of pregnancy, inseminating intra-cervically.

Adventitious placentation in a cow. 

Keywords: placenta, adventitious, placentitis, bovine, cow, infertility

Small to large irregular placentome-like structures may develop on the placenta adjacent to normal placentomes. These have been referred to as "adventitious" placentomes and the condition itself as "adventitious placentation. The word adventitious is derived from the Latin meaning "coming from outside" but in zoology, it refers to something that is in an unusual position or place. The adventitious placentomes may be localized or spread throughout the allantochorion/endometrium.

It is often stated that adventitious placentation is associated with hydrops conditions but it may occur in seemingly normal pregnancies. However, when adventitious placentation is obvious, one should probably consider the placenta and uterus as a unit and cull the cow because of the potential for infertility.

Luteinized follicles. COD in a cow.

Keywords: COD, cystic, ovarian, ovary, luteinization, disease, cow, production, bovine

Several follicles in one ovary show various degrees of luteinization after chronic low-grade LH stimulation. The presence of numerous follicles indicate that there was no deficiency of FSH in this cow. As is usually the case for cows with cystic ovarian disease (COD) this cow would probably not have shown estrus for a prolonged period of time.

It was once believed that these cows would not ovulate while cystic structures such as these persisted in their ovaries. However it has since been shown that estrous cycles may resume with ovulations adjacent to these cystic structures.

COD in dairy cows is usually associated with high levels of milk production; in beef cows is associated with the use of steroid containing growth promoters.

Leucosis in a bovine uterus

Keywords: leucosis, bovine, neoplasia, uterus, infertility

Image size: 1600 x 961px

Enzootic bovine leukosis is a result of infection by bovine leukemia virus (BLV). Interestingly, less than 1% of all the cattle infected with this virus actually develop lymphoid sarcomas.  It is characterized by the development of tumors of lymphatic tissues but tumors can be found throughout the body; in this case, the uterus. Although substantial numbers of nodules and diffuse thickening due to leucosis can be found in the uterus, severely affected genital tracts are occasionally found to be pregnant.

Management procedures that transmit blood have the potential to transmit BLV i.e. injections, surgery, tattooing, dehorning etc. It is not clear if biting flies are able to transmit this disease. Although rectal examinations were once incriminated in the spread of BLV, research suggests that under normal conditions this does not occur.

Dairy cattle. Estrous detection

Keywords: estrus, detection,infertility management, mounting, crowding, signs, computer, programs

Estrous detection is a major challenge for dairy farmers, especially as cows produce more milk and there are endocrine profiles are modified.

In a group of animals such as this, the farmer will spend time looking for any cows that may be allowing mounting by another cow; a sign of standing estrus. Allowing mounting is however prone to misinterpretation in a situation such as this. These cattle are crowded and even cows that are not in heat may be mounted because they are unable to move away from the cow attempting to mount them.

Additional signs of estrus in a cow include rubbing of the hair on the base of the tail, mucous discharges from the vulva, dried mucus on the tail, restlessness and mud on and animal's flanks from when others have attempted to mount it. After estrus, metestral discharges will be seen. Although metestral discharges inform the farmer that estrus has just been missed, they can be used to determine the time of onset for the next estrus period or in proactive situations, when prostaglandin should be given to shorten the luteal phase.

As shown at lower right, a farmer is consulting a 21-day estrous detection chart from this herd, to determine if mounting is real or spurious. Telemetry devices that monitor cow movement and sophisticated dairy management computer programs are also available to assist farmers in estrous detection.

The bovine estrous cycle

Keywords: estrus, estrous, progesterone, prostaglandin, estradiol, LH, FSH, bovine, cow

Note: The use of estrus as an adjective is less common than estrous (1.23 million vs 840 thousand Google hits respectively). Nevertheless, estrus is often used as an adjective e.g estrus cycle, estrus behavior, estrus synchronization etc. Indeed, it has become so common as to be regarded as both a noun and an adjective. However, the author adopts the more common term estrous as an adjective in this entry. In the British commonwealth, the terms oestrus and oestrous are used for the noun and adjective respectively.

The image shown here is useful for explaining the bovine estrous cycle*. It shows the rise of estradiol 17 beta that brings the cow into heat and causes a surge of luteinizing hormone (LH). Ovulation usually occurs about 16 to 24 hours after the onset of the LH surge i.e. when the cow is no longer showing signs of estrus.

After ovulation has occurred, a corpus luteum forms from the structure that was previously the follicle, producing progesterone (the yellow profile)  for approximately 19 days. If the cow is not pregnant, at about 15 to 16 days after ovulation, the endometrium releases prostaglandin F2 alpha (PG) which causes luteolysis i.e. the demise on the corpus luteum. Immediately after ovulation has occurred a new wave of follicle growth begins because inhibin production by the previous large follicle, is no longer present. This results in an elevation of follicle stimulating hormone (FSH).

A dominant follicle is selected in each follicle wave, suppressing its cohorts. If that follicle does not ovulate, it undergoes regression and a new follicle wave begins. There are usually three such follicle waves during each estrous cycle but in young animals, there may be only two waves, resulting in an interovulatory interval that is a few days shorter than a conventional estrous cycle of  21 or 22 days.

Standing estrus last for about 8 to 12 hours in most dairy cows but may be much shorter (and difficult to detect) in high producing cows. Very short estrous periods are typical of zebu-type cattle as well.

*Readers are strongly encouraged to consult an excellent resource on the bovine estrus cycle developed by Dr Roberto Palomares, Kip Carter and colleagues at The College of Veterinary Medicine, University of Georgia. The presentation is available for Apple or PC use.

The Apple OS version has full animation. Lacking some animations, the PC (epub) version however remains valuable for all students of reproductive physiology. On most PC computers, the ePub version can be viewed without downloading ePub readers.

Routine assistance during calving.

Keywords: obstetrics, calving, bovine, cow, twins, presentation, position, posture

Image size: 1568 x 1040 px

This series of images illustrates standard procedure for attending to a calving. In this case, the dam was a pluriparous Hereford cow.

In most cases, pluriparous cows give birth within one hour. . Up to three hours may elapse before calving is complete in a heifer. After those time frames, assistance should be considered. If however, one is present at the onset of calving, gentle and quiet intervention may be beneficial. In animals not accustomed to humans, unnecessary intervention may delay calving and should be avoided.

In this image (number one) the amnion has just begun to show at the vulva lips. This means that the allantochorion (chorioallantois) has ruptured already, releasing allantoic fluid.

Routine assistance during calving. 2.

Image size: 1912 x 1312 px

In this image (number two) the amnion is still in tact and two forelimbs and the nose of the calf has been presented at the vulvar lips. Normally, presented cranially and longitudinally. The position of the calf is usually dorso-left ilial or dorso right- ilial, moving into dorso sacral quite quickly. Normal posture for the calf is with its head resting upon its two forelimbs. If calving appears to be progressing slowly, it may be beneficial to rupture the amnion manually and assess presentation position and posture before dystocia becomes established.

Routine assistance during calving. 3.

Image size: 18988 x 1333 px

In this image (number three) the operator is scrubbing his hands and arms in preparation for intervention. It is important to exercise good hygiene if assistance is to be given during calving. In this case an iodine-based scrub is being used but for practical purposes, there are physical cleansing with ordinary soap and water is usually sufficient. The use of gloves is not recommended; traction is compromised and handling of the calf and fetal membranes is complicated through the use of gloves.

Waterproof, washable calving suits are available but may be uncomfortable in hot weather.  Otherwise, clothing should be discarded and washed.

Routine assistance during calving. 4.

Image size: 1961 x 1251 px

In this image (number four) the operator has ruptured the amnion manually and some amnionic fluid has escaped. Normally they are about 8 L of amniotic fluid and about twice that amount of allantoic fluid.

Routine assistance during calving. 5.

Image size: 1707 x 1316 px

In this image (number five) the operator and has established that the head and forelimbs presented at the vulvar lips belonged to the same calf! If possible in some cases for twins to be presented simultaneously; this possibility should be eliminated before any traction is applied to the head or limbs; exacerbating dystocia.

Routine assistance during calving. 6.

Image size: 1928 x 1312 px

In this image (number six) traction is being applied to both forelimbs and the head is following spontaneously. In cases of dystocia, calving chains and perhaps even a head snare would have been applied to increase purchase on the calf. It is sometimes difficult to decide exactly how much traction should be applied and when too much traction is necessary to deliver the calf per vagina (necessitating a cesarean section). In general, two average sized adults should be able to deliver a calf per vagina if its presentation posture and position are normal. If it is obvious that the fetus is relatively or actually oversized, as is often the case with beef cattle, one should defer to a cesarean section as soon as possible.

Routine assistance during calving. 7.

Image size: 1950 x 1307 px

In this image (number seven) the elbows of the calf had been grasped and the calf has been rotated through about 120° so that the widest measurement of the fetal pelvis (across the heads of the femoral trocanters) lies dorsal ventral in the maternal pelvis. This helps to prevent hip lock in the maternal pelvis.

Routine assistance during calving. 8.

Image size: 1917 x 1298 px

In this image (number eight) mucus and other debris is being removed from the calf's mouth. If suction is available, it should be applied now. Some ranchers hang calves vertically for a few minutes at this time or even swing them around centrifugally in an effort to expel the mucus in the upper respiratory tract. However this may put excessive pressure on the diaphragm and compromise oxygenation therefore is generally not advisable.  Oxygen can be administered by face mask if available. The value of buffers (NaBicarbonate and TRIS) as well as analeptics such as doxapram hcl are questionable.

At this time, it is also appropriate to check for the presence of a cleft palette in the calf.

Routine assistance during calving. 9.

Image size: 1963 x 1312 px

In this image (number nine) the calf is being rubbed vigorously in an attempt to vitalize it; mimicking the vigorous licking of the calf by the dam that normally occurs at this time. One should determine the gender of the calf and also ensure that no umbilical or inguinal herniation is present. The umbilical cord should be disinfected with 0.5% chlorhexidine. Disinfection should be repeated 12 to 24 hours later.

Routine assistance during calving. 10.

Image size: 1927 x 1298 px

In this image (number 10) a helper is continuing to stimulate the calf, close to the dam's head, allowing some fetal-maternal bonding to occur. Excessive helping or interference may compromise fetal-maternal bonding, especially in animals not habituated to humans. At this time the operator is examining the reproductive tract for any signs of damage that may have occurred during delivery and importantly is also examining the uterus for the presence of a second calf.  Intra-uterine antibiotics or disinfectants should not be administered routinely after calving. Their value is questionable; indeed this practice has also been associated with an increased calving to conception interval.

Routine assistance during calving. 11.

Image size: 1878 x 1312 px

In this image (number 11) a second calf was indeed present. It was delivered in the same manner as the first calf and the uterus was again investigated for the presence of a third calf which was not present. At this time, the dam should be allowed to bond with her calves with minimal interference from humans.

Uterus of a newborn calf.

Keywords: uterus, bovine, calf, caruncles, neonatal, pregnancy

The uterus of a newborn calf. Uterus was floated in water to accentuate anatomical structures. This showed well-formed caruncles at the time of birth. Obviously therefore, pregnancy is not necessary for the development of caruncles.

Cervical mucus in a cow

Keywords: mucus, estrus, cervix, bovine, cow, detection, Spinnbarkheit, sodium chloride, NaCl, conductivity

Image size: 1312 x 986px (click to enlarge for best focus).

Mucus accumulation around the cervix of a cow during estrus. This mucus is being produced by the cervical glands around the external cervical os. Apart from its physiological value of lubricating the tract, it's presence is a valuable management tool tool because it is discharged at the time of estrus in cows, facilitating estrous detection. 

The elasticity of the mucus is obvious in this image. The stretchiness of this mucus is sometimes referred to as Spinnbarkheit from the German word for "ability to spin (into thread) because it becomes thread-like when it is most able to stretch. In humans, this phenomenon is sometimes used to determine the optimal time for artificial insemination.

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Also, vaginal mucus from a cow in estrus, stretched between two glass slides:

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The concentration of salt (sodium chloride) increases during estrus therefore the ability of cervical mucus to conduct electricity also increases at that time. Instruments that measure conductivity of cervical mucus are available to assist one in determining the stage of the estrous cycle.

Prolonged gestation in a cow

Keywords: prolonged, gestation, ACTH, cortisol, bovine, cow, pregnancy, adrenal

Normal gestation is approximately 280 days for cattle. This heifer calf was delivered by cesarean section at approximately 317 days of gestation. This was the second pregnancy for this cow, her previous pregnancy having been normal. The calf weighed 46.5 kg, within the normal range for Holstein neonates.

Pregnancy had been diagnosed by ultrasonography at 30 days, 50 days and 102 days of gestation. Examination at approximately 315 days using per rectum ultrasound revealed a viable calf of approximately normal size. After delivery by cesarean section, the calf attempted to breath but because of obvious abnormalities, it was euthanized using pentobarbital.

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Post-mortem examination showed a prolapse of cerebral tissue through a central orifice in the frontal bone, barely visible between the ears in the image above.

The image below shows the defect in the frontal bones and the prolapsed portion of the cerebrum:

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Most of the cerebral hemispheres appeared to be missing. There was slight asymmetry in the face and both eyes were present but the optic nerve appeared to have no connection to the optic chiasma. There was evidence of hydrocephalus. There was also a severe cleft palate.

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A longitudinal section of the brain after formalin fixation confirmed the presence of severe hydrocephalus in all the ventricles and severe hypoplasia of the cerebellum and cerebral hemispheres. The brain and adrenals of a control calf were available for comparison.

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The longitudinal section clearly demonstrated meningeocele/encephalocele (outlined in yellow here). Histology showed that it contained a large amount of fibrous tissue, some neuronal tissue and some epithelial lined cavernous sinuses.

As seen in the inset, the eyes themselves were grossly normally formed but as mentioned, the optic nerve did not appear to connect to the optic chiasma. The adenohypophysis in the affected calf was distorted and partially absent.

The adrenal glands were approximately 25% of the size of the adrenal glands on a normal calf and on gross examination, when compares with the cross sections of the normal adrenals, the adrenal and cortex appeared to be equally represented in proportions in both the normal and abnormal calf but was far smaller in the calf with prolonged gestation. Histology showed that adrenal gland had all three critical layers present i.e. the zona glomerulosa, zona fasiculata (where cortisol is produced) and zona reticularis.

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Histopathology showed that the pituitary gland contained both neuro-and adenohypophysis but no attempt was made to quantify acidophils or basophils.

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Collectively, these findings suggest a quantitative lack of the ACTH-adrenal cortical resources, not an absolute absence. This deficiency probably led to adrenal hypoplasia with consequently prolonged gestation.

Prolonged gestation in a cow

Keywords: prolonged, gestation, bovine, ACTH, pituitary, skull, eyes, calf, ultrasound, ultrasonography

The dam of this calf was determined to be pregnant by transrectal palpation, 45 days after breeding. When she had not calved after 10 months, the breeding records were questioned.

Shortly before calving,  this pregnancy was examined by transrectal ultrasonography. At that time the amniotic fluid appeared to be cloudy and fremitus was absent. The udder had enlarged in preparation for calving.

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Fifteen months after breeding, the pregnancy terminated spontaneously but assistance was required at calving. The attending clinician was unable to touch the calf and initially presumed that it had been aborted in the field. A plank was then used to elevate the cow’s abdomen. This enabled the delivery of a dead 55 kg male calf; in posterior longitudinal presentation. Although the birth was spontaneous, it is doubtful if the calf would have been born without assistance.

The placenta was retained and was unavailable for examination.

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Postmortem showed many fetal defects including the absence of grossly visible contents of the sella turcica i.e. the pituitary gland appeared to be absent. See white ring in image above.

There was micro-ophthalmia, with the eyes only developing subcutaneously. See yellow ring in image above. A well-developed tentorium ossi separated the cerebellum and cerebrum completely and there was only a single cerebral hemisphere with absence of the development of sulci. The cerebral hemisphere was about 20% the size of that of a control neonatal calf.  As shown above, there was a complete cleft palate and (below) significant facial-cranial twisting was evident.

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The incisor teeth (see above) had only erupted partially; unusual because they have usually a ruptured completely birth. The thyroid gland was subjectively smaller than that of a normal neonate but the adrenal glands were normal in size compared to those of the aforementioned control calf.  The testicles of the calf were not examined.

In general, the cause of prolonged gestation is presumed be due to malfunction or absence of ACTH secreting cells (acidophils) in the adenohypophysis of the pituitary gland. This calf did not appear to have the pituitary gland, consistent with that theory. However, the normal sizes of the adrenal glands were not consistent with that finding suggesting some other source of ACTH. This also suggested that the problem elsewhere in the cascade of hormonal events leading to parturition. Also, total absence of the adenohypophysis was not consistent with the apparently normal growth of the calf because growth hormone-releasing hormone would not have been produced in this calf and growth hormone does not cross the bovine placenta. In combination, these findings suggest an alternate source of ACTH and growth hormone-releasing hormone; perhaps diffuse cells in the area of the sella turcica.  The calf was in a fairly advanced state of autolysis when examined therefore some adenohypophyseal tissue may have be present but not visible.