DYSTOCIA IN CANINES : MAXIMISING SUCCESS THROUGH ASSISTED WHELPING
Dystocia is defined as difficult birth or inability of the dam to expel the fetus through
the birth canal without assistance. Dystocia is a frequent emergency that all veterinarians
may encounter, irrespective of their specialization in canine reproduction. Therefore, it’s
crucial for every veterinarian to be able to recognize the signs of dystocia. This allows
for prompt action, which is vital for the survival and well-being of both the dam and
the pups. To understand dystocia, it’s essential to understand the normal process of
whelping. Over the years, the approach to diagnose and treat dystocia hasn’t changed
much except for a greater acceptance of surgical intervention for management. This
lecture aims to give a summary of the most frequent reasons for dystocia, which is
difficulty in giving birth, and to discuss strategies for managing dystocia using nonsurgical
methods.
NORMAL WHELPING
The process of parturition in dogs is a complex interplay of hormones and
physiological changes. It begins with the maturation of the fetus, which triggers a series
of hormonal changes in the mother. The cortisol levels in the mother peak 24 hours prior
to parturition, which is associated with the maturation of the fetal hypothalamic-adrenal
axis and the secretion of ACTH by the adrenal glands. This is followed by an increase
in prolactin level 12-24 hours before the onset of parturition. This rise in prolactin is
believed to be responsible for the restless behavior and prodromal signs observed in
the bitch during this stage of labor. Following the cortisol surge, serum progesterone
levels fall, resulting in the onset of stage I labor 24-36 hours later (O’Neill et al., 2017).
This intricate process is divided into three stages: preparation of the uterus and cervix
for birth (stage I), active labor (stage II), and the passage of the fetal membranes (stage
III). Any deviation from this normal process may be an early sign of dystocia, a condition
that can pose serious health risks to both the mother and the puppies. It’s important to
monitor the bitch closely during this time to ensure a safe and successful delivery.
Progesterone, drops significantly 12-24 hours before labor begins, causing the
dam’s body temperature to decrease by 1.5-2 degrees Fahrenheit (Concannon et al., 1989). This temperature drop is often used as a sign that labor is imminent. However,
this drop is highly variable and can be unpredictable, so it should not be used as the sole
indicator for planning procedures like Caesarean sections.
The duration of stage 1 can vary greatly, with some dogs, particularly primiparous
bitches may take 24 hours or more. However, for most dogs, this stage typically lasts
between 6 to 12 hours (Gendler et al., 2007). This stage is a crucial part of the birthing
process, preparing the body for the delivery of the puppies. Stage II of labor in dogs
begins with the rupture of the fetal membranes and ends with the delivery of the last
puppy. During this stage, the dog’s body temperature will have returned to normal.
It’s important to note that a significant percentage of dogs show signs of dystocia,
or difficulty in giving birth, before the first puppy is delivered. This makes this stage
critical for identifying potential complications. The stretching of the pelvic inlet and cervix
triggers the Ferguson’s reflex, leading to the release of oxytocin and causing abdominal
straining. Typically, the first puppy is delivered within 4 hours after the rupture of the
allantochorionic membrane, which is part of the fetal membranes. This stage is crucial
for the safe delivery of the puppies (Gendler et al., 2007).
During stage II of labor in dogs, mild and occasional vomiting is common due to the
pressure exerted by the fetuses and the abdominal press. However, this vomiting should
not be severe or prolonged. To maintain proper nutrition and hydration during this stage,
the dog can be offered water and food that contains glucose and calcium. The duration
of this stage can vary based on factors such as the dog’s parity (number of previous
pregnancies), the size of the litter, and the breed of the dog. On average, this stage lasts
between 4 to 18 hours. During the birthing process, puppies are born from alternating uterine horns, starting with the horn that has the most puppies. Puppies are typically born every 30 to 60 minutes, but there can be a gap of 2 to 3 hours between births without any signs of distress in the puppies (Van Der Weyden et al., 1989)
It’s not uncommon for a bitch to have a temporary “whelping pause,” which allows
for the dispersal of lactic acid that has built up in the uterine muscle. During this pause,
she will not have any abdominal contractions, will rest, care for her puppies, and show
no signs of distress (Linde Forsberg, 2015).
After this rest period, labor will continue until all the puppies are born. While there
have been anecdotal reports of live puppies being born up to 36 hours after the onset of
Stage II labor, this is a very rare occurrence and should not be considered normal. Finally,
puppies can be born in either an anterior (head-first) or posterior (feet-first) position, with
60% of puppies being born in the anterior position and 40% in the posterior position.
Stage III of labor in dogs is characterized by the passage of placentas and often
happens at the same time as stage II, when the puppies are being born. The placentas
are usually delivered along with the puppies. It’s important to remove these placentas
from the bitch to prevent her from eating them, which can often lead to diarrhea or, in
severe cases, choking or obstruction. There’s no known benefit to the bitch from eating
the placentas. Because placentas are typically passed with the birth of the puppies, it’s
uncommon for a dog to retain placentas after giving birth. This stage is crucial for the
health and well-being of the dam after the delivery of the puppies.
DYSTOCIA
Dystocia, is a term used to describe a difficult or abnormal birth. This condition
can occur when a bitch is unable to successfully deliver puppies through the vaginal
canal. It’s diagnosed when birth doesn’t occur as expected or within a reasonable timeframe.
Early recognition and intervention of dystocia are crucial for the health of both
the dam and the puppies. While the overall incidence of dystocia is relatively low, it can
be significantly higher in certain breeds, such as brachycephalic breeds, where it can
approach even100%.
PREDISPOSING FACTORS AND CAUSES OF DYSTOCIA
Dystocia, or difficult birth, happens in about 5 per cent of all births in dogs and
might be due to maternal or foetal factors or both.
MATERNAL FACTORS
Maternal causes include a small pelvis, abnormalities in the lower reproductive
tract, lack of uterine contractions (primary or secondary uterine inertia), poor nutrition,
parasites, other uterus abnormalities, and abnormal expulsion due to non-uterine
causes.
Primary Uterine Inertia
Primary uterine inertia is a condition where the uterus fails to contract sufficiently to
expel the fetus. It can be complete, where no signs of second stage labor are detected
and gestation has exceeded its expected length, or partial. The causes of primary uterine
inertia in bitches can range from small litters due to inadequate uterine stimulation, to
large litters resulting from overstretching of the myometrium, hypocalcemia, obesity,
uterine infection, uterine torsion, and trauma. Environmental disturbances can also
contribute to primary uterine inertia, as many bitches can delay parturition until they are
alone, comfortable, and in familiar surroundings (Van Der Weijden and Taverne, 1994).
Bitches with primary uterine inertia often show a greenish-black vulvar discharge,
known as uteroverdin, which is produced from the marginal hematomas of the placentas.
If this discharge is observed without the delivery of pups within 1-2 hours, it is considered
a medical emergency.
The presence of uteroverdin is an indication of placental separation. If the litter is
not delivered promptly, the puppies may suffer from hypoxia (lack of oxygen), which can
lead to their death. Therefore, immediate veterinary attention is required in such cases
to ensure the health and safety of both the dam and her offspring.
Secondary uterine inertia
Secondary uterine inertia, or uterine fatigue, can be a primary cause of dystocia
or may occur secondarily during dystocia of another cause. If the birth canal is blocked
and uterine contractions stop and remain stopped even after the blockage is relieved,
the dystocia is then attributed to secondary uterine inertia (Gaudet., 1985). Dystocia can
be diagnosed if labor doesn’t initiate at the right time, if there are signs of maternal or
foetal compromise.
Obstructive dystocia
Obstructive dystocia occurs due to various factors like small pelvis, uterine torsion,
ruptures in the uterus, inguinal herniation, abnormalities in the lower reproductive tract
and in the soft tissues of the vagina or vulva. To prevent complications during whelping,
it’s recommended to perform a manual examination of the vagina and vestibule before
the process. This examination can help identify any irregularities such as bands or
narrowings (strictures) in the vagina that could obstruct the normal delivery of the pups.
These defects might not be noticeable during breeding because methods like vaginal or
transcervical insemination can bypass these obstructions (Runcan et al., 2018).
This is often seen in brachycephalic breeds, such as the Boston Terrier, Pug, and
French Bulldog and has also been reported in achondroplastic breeds, such as Corgis
and Scottish Terriers (Munnich and Kuchenmeister, 2009).
Older bitches, particularly primiparous bitches over the age of six, are more prone
to dystocia, or difficulty in giving birth, compared to younger ones. This is because
advanced age predisposes them to single-pup pregnancies, uterine inertia, and
prolonged parturition. One study in UK, found that bitches aged between three to six
years have three times higher odds of experiencing dystocia compared to their younger
counterparts
Miscellaneous causes
*. Excessive nervousness
*. Metabolic disturbances
*. Hypoglycemia
*. Hypocalcemia
FOETAL FACTORS
Foetal causes include deformities, being too large (either in general or relative
to the maternal pelvis), incorrect positioning or posture, and death. Cephalopelvic
disproportion may cause dystocia in brachycephalic bitches.
Oversized foetus
The presence of a large fetus, which can happen if there’s only one puppy (known
as a singleton puppy), oversized foetus, often secondary to prolonged gestation,
oversized fetal heads with prevention of normal passage of foetus in the pelvic canal
(Linde Forsberg, 2015).
Fetal abnormalities such as anasarca (also known as “water puppy”), where the
fetus has an excessive amount of fluid underneath its skin, hydrocephalus, or a “fetal
monster”, which is a term used to describe a fetus with severe congenital abnormalities
(Linde Forsberg, 2015).
Foetal Malpostures
Malposture refers to abnormal positioning of the fetus during birth. This can
include situations where the fetus’s head is extended forward but its shoulders are held
back. This is often seen in dolichocephalic breeds, which are breeds with elongated
skulls such as Greyhounds or Collies.
In a transverse presentation, the fetus is positioned sideways. While the limbs may
be felt during a manual examination, the fetus may move up the opposite uterine horn
(contralateral uterine horn), causing a blockage.
If the cause of dystocia (difficult birth) is not immediately clear from a manual
examination, a radiograph (an X-ray) can quickly help identify if malposture is present.
This information can then guide the selection of the most appropriate treatment strategy.
Miscellaneous causes
In some cases, if the first puppy is in a posterior position, it can lead to dystocia due
to inadequate Ferguson’s reflex and insufficient dilation of the cervix. The Ferguson’s
reflex is a neuroendocrine reflex where pressure on the cervix during labor leads to the
release of oxytocin, stimulating uterine contractions. If this reflex is inadequate, it can
hinder the normal labor process and lead to dystocia.
DIAGNOSIS
Successful management of dystocia depends on differentiation of the contributing
factors. An accurate history is important.
*. Actual gestational length has to be accurately calculated
*. The preovulatory LH rise can be estimated by serum progesterone concentration;
whelping should occur 65 ± 1 days later.
*. The first day of diestrus can be determined by vaginal cytology and vaginoscopic
examination of mucosal folds; whelping should occur 57 ± 3 days later.
*. Estimation of whelping dates from breeding dates is inherently inaccurate
due to the long period of sexual receptivity in the bitch.
Careful physical examination of the bitch
. Vital signs
. Abdominal palpation to determine uterine tone, presence of fetus (es)
. Digital vaginal examination for the presence of a fetus in the vaginal vault, and
to determine the nature of vaginal/pelvic ligament tone and vaginal discharge
. Direct visualization or palpation of the cervix (difficult in the bitch due to vaginal
anatomy)
. Evaluation of the mammary glands for colostrum
Ancillary diagnostics
. Abdominal ultrasonography to evaluate fetal viability
. Abdominal radiography to evaluate litter size and the presence of remaining
fetuses, or to rule out obstruction of the birth canal
. Plasma progesterone concentration of the bitch at term of <2 ng/ml
Obstetrical aid in dystocia
To secure a successful delivery of live, undamaged puppies without harming
the dam, obstetrical aid may be carried out in various ways: extraction of the fetus;
episiotomy; embryotomy; medication; or surgical delivery, that is, caesarean section or
hysterectomy.
Manual removal of the foetus
Delivery by manual assistance is indicated in fresh, non-protracted cases, such as
malpresentation of a fetus that may be corrected per vaginum, and in cases of slight
relative oversize that can be overcome by traction. In inertia which does not respond to
medical treatment, delivery by traction may be successful.
The bitch is best placed on a table in a standing position and perineum should
be cleaned. Adequate lubrication using obstetrical or sterile, water-based lubricant can
be applied to the vaginal canal. Lubricant may be applied cranial to the fetus via the
passage of a red rubber catheter and syringe. The fetus should be grasped by the neck
or pelvis, as the limbs do not have bony attachment and can be easily pulled from the
body. Traction should be applied in a ventral direction (of the dam) to help guide the
fetus downward through the caudal vagina and vestibule using a side-to-side wiggling
motion to help guide the shoulders and pelvis through the bitch’s pelvic girdle. the hind
quarters cleaned. The fetus may be extracted either with the fingers or by forceps, using
sufficient amounts (Runcan et al., 2018).
Gentle manual stretching of the entrance to the vagina (the vestibule) and the
external part of the female genitalia (the vulva) may be tried. In more severe cases, a
surgical procedure called an episiotomy might be performed. This involves making a
surgical cut from the vaginal opening up the perineum (the area between the vulva and
anus) to help the puppy pass through. Once the first puppy is successfully born, the rest
of the litter often follows more easily. This is because the process of birthing the first
puppy causes the vagina and vestibule to fully dilate (open up). This is particularly true
for primiparous dams.
- Digital extraction
Digital correction and extraction may be carried out by one or two fingers inserted
in the vagina, the other hand grasping the fetus through the abdominal wall and leading
it towards the pelvic inlet. A fetus in anterior presentation is fixed just behind the head,
and in posterior presentation anterior to the pelvis. A fetus, especially if alive, should
never be extracted by fixing a leg because of the risk of damaging it. The direction of
traction should be in the natural direction of expulsion, that is initially dorsocaudally
guiding the shoulder of a fetus in anterior presentation or the pelvis of a fetus in posterior
presentation into the pelvis by the use of semirotatory movements. Thereafter the
direction is altered to caudoventral in order to adjust the fetus as easily as possible to the
natural direction of expulsion. Traction should be synchronized with uterine contractions
and should not be too strong at first, because the birth canal needs some time to adjust
its size to that of the fetus.
If the fetus is unable to be introduced into the vaginal canal, gentle manipulation may
be attempted per abdomen (in toy breeds), or transrectally. Often the fetus needs to be
positioned caudally behind the pelvis to enable enough room for mutation. Manipulation
should be attempted between periods of abdominal straining to avoid injury to bitch or
pup. In the case of a large fetus that is unable to engage the pelvic canal, turning the
fetus 45 degrees may create sufficient room to allow the fetus to pass through the pelvis
into the vagina. Lastly, the bitch may be placed in a “wheelbarrow” position by raising her
hind legs over her pelvis and allowing her to stand for a few minutes. Often this allows
gravity to pull the uterus and pups cranial which can facilitate appropriate repositioning
of a pup for delivery.
- Forceps extraction
If a puppy has unfortunately died in the womb, forceps (a type of surgical instrument)
can be used to gently pull out the puppy. This is usually a last resort and must be done
very carefully to avoid causing damage to the lower part of the bitch’s reproductive tract.
Instrumental delivery can be carried out by means of various kinds of special forceps,
such as Hobday’s, but ordinary forceps such as Rampley’s sponge-holding forceps can
also be used. Forceps without a ratchet are preferable as there is then no temptation to
close the forceps completely. A forceps delivery should never be undertaken if the fetus
is totally out of reach of the finger. The forceps may be used in such a way so as not
to grasp the vaginal wall. This can be ensured if they are always applied with a rotatory
movement before being closed and only between uterine contractions.
In anterior presentation the forceps, guided by a finger, should grasp the upper jaw,
the lower jaw or the whole nose. When the head has been drawn through the pelvis,
the fingers take over. Extraction can also be tried by gripping the folds of skin on each
side of the head with the forceps.
In anterior presentation traction may also be applied to the puppy’s head using a
Hobday’s vectis placed over the head and behind the occiput, and with a finger under
the head. An ovariectomy hook fixed into the soft area between the mandibles may be
used to apply traction to the fetus forming – with the middle finger in the mouth of the
fetus – pincers on the symphysis of the lower jaw.
In posterior presentation forceps may be used to grasp folds of the skin lateral to
the thigh or the pelvis. If the posterior part of the fetus has already passed the pelvic
inlet, Hobday’s vectis can be used for delivery placed over the dorsal part of the fetal
pelvis behind the tuber coxae and with the index finger pressing upwards in front on the
fetal pelvis.
Forced traction may be used for delivery of a dead fetus with a firm grip across the
fetal cranium or pelvis.
Abnormal position or posture
Abnormal position or posture should be corrected before traction is applied.
Manipulation is helped if the position of the fetus is fixed by gripping it with the left
hand through the abdominal wall. Deviation of the head is corrected simply by inserting
a finger into the mouth of the fetus. Flexion of limbs either in anterior or posterior
presentation is corrected by curling a finger around the retained limb and drawing it
upwards and backwards into the maternal pelvis.
In those cases where two fetuses from opposite horns obstruct one another, one
is retained while the other is extracted. If there is one fetus in anterior and one in
posterior presentation, the latter should be extracted first because the pelvis is more
easily brought into the birth canal than the head.
Dystocia due to dorsoventral cord formation in the vagina making digital delivery
impossible may be overcome either by cutting the cord which is seldom accompanied
by serious bleeding, or by caesarean section.
Medical Management of Dystocia
If a bitch is healthy, not in extended labor, and there are no signs of complications
/ obstruction in the vaginal passage or distress in the puppies, medical intervention can
be considered. The goal of this intervention is to first address any underlying issues. The
main pharmacological treatments used are calcium and oxytocin. Calcium is used to
enhance the strength of the contractions of the uterus, and oxytocin is used to increase
the frequency of these contractions (Humm et al., 2010). Oxytocin plays a key role in
causing smooth muscle (like that found in the uterus) to contract and it directly influences
the rate of calcium influx in to the myometrial cells. Therefore, oxytocin and calcium are
often used together when treating a condition called uterine inertia, where the uterus
has lost its ability to contract and expel the puppies.
Calcium
Hypocalcemia, is a common cause for difficult births in dogs. This condition is
believed to occur at the myometrial cellular level before it shows up in general circulation.
The best way to correct hypocalcemia in a whelping bitch is by administering a 10%
solution of calcium gluconate. This calcium solution can be given in two ways: as a slow
intravenous (IV) injection (10-20 mg/kg) while monitoring the heart for irregular rhythms,
or as a subcutaneous injection (22 mg/kg SQ, under the skin) (Berstrom et al., 2006)
If the calcium is given subcutaneously, it’s important to dilute it with an equal volume
of saline because calcium salts can irritate the skin and there’s a small risk of forming a
granuloma (a small area of inflammation) or skin sloughing at the injection site. It may
take up to 45 minutes for the subcutaneous calcium to show effects. Regardless of how
it’s administered, the calcium treatment can be repeated every 6-8 hours if necessary.
Pet owners often give oral doses of supplements containing calcium chloride during
labor, but this method is often ineffective during a difficult birth due to the slow absorption
rate of oral calcium.
Oxytocin
Oxytocin plays a crucial role in parturition and causes muscle contractions, milk
release, and strengthens maternal bonding. However, it should not be used obstructive
dystocia as it can worsen the situation and even lead to uterine rupture. In terms of
dosage, small amounts (0.25-1 unit) are recommended, with a maximum limit of five units
per bitch, regardless of size. Larger doses can lead to excessive uterine contractions
and foetal hypoxia, and are generally less effective.
Oxytocin can be administered subcutaneously, intravenously, or intramuscularly.
The dose can be repeated every 15-30 minutes (Smith, 2012). If two to three doses
have been given without a puppy being born (and the mother’s contractions are strong),
it indicates that medical management has failed and a Caesarean section is required. If
a puppy is born and the delivery proceeds normally, the oxytocin administration protocol
can be restarted. Oxytocin can be given every 30 minutes as long as puppies continue
to be delivered, but should be stopped if it fails to induce contractions (Linde Forsberg,
2015).
Treatment of dystocia varies according to the contributing factors.
. The presence of obstruction, either maternal or fetal in origin, is an absolute
indication for cesarean section.
. Metabolic abnormalities may respond to medical intervention once obstruction
has been ruled out
. Fetal heart rate of less than 180 bpm indicates fetal stress and Caesarean
section is often warranted. If the fetal heart rate is below 150 bpm consistently,
profound fetal stress is evident and a Caesarean section should be performed
immediately .
. In cases of dystocia where more than six to eight puppies are remaining,
medical management is unlikely to be successful due to maternal and uterine
fatigue, therefore caesarean section is warranted .
Conclusion
The best outcomes in managing whelping are achieved when issues are quickly
identified and addressed by a knowledgeable owner and veterinary team. Often, a
Caesarean section is the fastest and safest option for both the dam and pups. However,
careful medical management, if used judiciously, can also help resolve dystocia. The
choice of medical management should be based on the presenting situation, and the
health of the bitch and puppies must be thoroughly assessed before deciding on the
course of action. It’s important to note that oxytocin, should not be used if there’s a
physical obstruction or if the cervix hasn’t dilated.
The most successful outcomes are usually achieved when problems are detected
and corrected within the first six hours of active labor. Therefore, it’s crucial for everyone
involved to act swiftly to identify any issues and intervene appropriately for the best
outcome for both the dam and her pups.
BREEDING- WHELPING AND PUPPY CARE PRACTICES
BREEDING- WHELPING AND PUPPY CARE PRACTICES
Compiled & Shared by- This paper is a compilation of groupwork provided by the Team, LITD (Livestock Institute of Training & Development)
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