MANAGEMENT OF PREGNANCY AND NEONATAL CARE IN BITCHES

April 18, 2024

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MANAGEMENT OF PREGNANCY AND NEONATAL CARE IN BITCHES

G Shalini and Y Nagendra Reddy

Ph.D Scholar, Department of Animal Reproduction, Gynaecology and Obstetrics, CVAS, Mannuthy, Thrissur, Kerala

Introduction

Breeding control is the first step toward managing pregnancy. Breeding operations should only use animals that are normal, healthy and good body condition. Age, nutrition, physical condition and general health all have a significant impact on fertility (Johnson, 2008). Litter size in the bitch varies by breed, smaller breeds typically produce smaller litters than larger ones. In Beagles between the ages of 2 and 3.5, conception rates and litter sizes are highest and newborn mortality is lowest. Conception rates and litter size start to decrease beyond the age of five, while newborn mortality starts to rise. Parity affects litter size as well, the greatest litters occur at third and fourth parity (Kelley, 2002; Bobic Gavrilovic et al., 2008). The chance of dystocia is higher in abnormally large pups, such as those that could result from a singleton pregnancy. When it comes to dystocia, bitches under one year old may be more vulnerable than older ones. Obesity is linked to smaller litter sizes, higher incidence of dystocia, and poorer conception. Poor lactation and infertility are other possible symptoms of underconditioned animals. Pregnancy may be negatively impacted by any maternal sickness or its treatment. Maternal and fetal health are more at risk in situations where the maternal health is less than ideal. The expected risks determine how to handle and monitor a pregnancy. Recent developments in the reproduction of small animals have made it possible for pregnancy management to develop into a clinical service with applications from the start to the end of gestations. The developments enable more precise and advanced techniques for detecting pregnancy, enhanced utilization of ultrasonography to ascertain gestational age, evaluate fetal health and forecast the date of delivery, the monitoring of luteal function and possibility of progesterone supplementation by progesterone tests. Progesterone assays and managed breeding information are used to evaluate prolonged gestations and determine when to electively perform an interventive caesarean section, fetal and uterine monitoring is used to manage critical pregnancies late in gestation, ancillary and supportive therapy is used in caesarean and induced deliveries, anti-progestin therapy may be used to induce pre-scheduled whelping in normal pregnancies and there are several protocols available for ending unwanted pregnancies (Concannon and Verstegen, 2004).

Physiology of pregnancy and parturition

Fertilization takes place in the uterine tubes of the bitch, after which the fertilized eggs mature into morulae and eventually enter the uterus. Early blastocysts in bitches emerge
the uterus 11–12 days following the peak of LH. Embryos travel throughout the uterus 12–17 days following the LH surge, eventually becoming equally spaced within both uterine horns. The implant process is finished 22–23 days following the LH surge (Concannon et al., 2001; Reynaud et al., 2006). The bitch needs progesterone, which is produced by corpora lutea (CLs), for the pregnancy. The corpora luteal function can be evaluated by the serum progesterone levels. Serum progesterone levels peak between 7 and 14 days into the pregnancy, after which they progressively fall for the duration of the gestation. Within 48 hours of giving birth, there is a steady, quick drop in pregnant bitches levels to less than 2 ng/mL or roughly 6.4 nmol/L, before giving birth. Because prostaglandin F2a concentrations rise sharply, which does not happen during the non-pregnant cycle, progesterone levels abruptly decrease. Both pituitary LH and prolactin are necessary for the luteal release of progesterone.

In the second half of a pregnancy, prolactin serves as the primary luteotrophic agent. The placenta produces relaxin. It peaks 30-35 days after the LH surge and reaches detectable amounts in serum or plasma as early as 20 days following the LH surge. In bitches, prolactin and relaxin serum concentrations rise in the second half of pregnancy. Relaxin levels are elevated during pregnancy until delivery or termination, at which point they sharply drop (Concannon et al., 2001). Prior to parturition, the bitch’s concentrations of maternal prostaglandin PGF2a and cortisol (and maybe fetal cortisol) rise. While PGF2a rises in the bitch without an increase in estrogen, the serum concentration of estradiol rises in several species prior to parturition and induces prostaglandin secretion (Luz et al., 2006). Twenty-four hours before parturition, PGF2a induces luteolysis, which lowers serum progesterone to <1 ng/mL. Both oxytocin and prostaglandin induce uterine contractions. In addition to other processes, pressure on the cervix causes the release of oxytocin. The placenta separates due to a rise in prostaglandin and a reduction in progesterone. The placenta’s production of relaxin decreases sharply during parturition, but it can still be seen up to nine weeks after delivery. This is because trophoblast cells invade the endometrium and take longer to slough off when the canine uterus naturally involutes.

Management of Nutrition during pregnancy

The well-conditioned bitch may gain little to nothing in weight during the first three weeks of pregnancy. Unless the dog is underweight, eating a premium adult dog chow will suffice. Bitches who are really skinny when they get pregnant should consume a growth or performance food to quickly get healthy.
Many bitches lose their appetite around week three of pregnancy, and it usually lasts for a week or longer. Occasionally, minor vomiting and nausea accompany anorexia. Around week four, appetite will return.
Sometimes bitches don’t feel like eating all during pregnancy. The final half of pregnancy causes an increase in energy needs as well as a rise in protein and carbohydrate requirements. The increased intake of feed for growth, pregnancy, and breastfeeding typically provides this. A diet change that happens too quickly could upset your digestive system.
Later in gestation, a pregnant bitch’s dietary requirements rise proportionately to the size and growth of the litter. For every 20–55 percent rise in body weight, there is an average 40 percent increase in food consumption. The bitch finds it easier to eat several little meals because of the increasing intra-abdominal pressure caused by the expanding uterus.
During the final week of pregnancy, bitches with big litters could feel uncomfortable in their abdomens and lose their appetite. Some bitches, but not all of them, will cease eating 24 to 48 hours before giving birth.
Supplementing expectant bitches with vitamins and supplements is not advised. Supplementing with calcium is not advised.
Overconsumption of calcium raises the bitch’s risk of puerperal hypocalcaemia and suppresses the generation of parathyroid hormone, which is the hormone that the bitch produces.
Cleft palates and other congenital abnormalities have been linked to excessive vitamin A intake. Human fetal abnormalities have been linked to folate deficiency. Although high-quality dog meals should provide adequate folate, taking B vitamin supplements is safe. Dogs do not need vitamin C supplements because they generate plenty of it naturally. Overdosing on vitamin D could make it more difficult for the body to mobilize calcium. The fetuses’ brain and retinal development will be maximized by omega-3 fatty acid supplementation.
Maintaining physical fitness throughout pregnancy requires regular exercise. Exercise that is the safest is brisk walking and short swims.

Exercise during pregnancy

Bitches with large litters may have to restrict this to brief outings during late gestation. Heavy work activities should be discontinued by performance bitches who are pregnant. Herding, agility, field, and advanced obedience training are not advised owing to the possibility of abdominal damage and the stress they may cause the fetuses.
Moderate uterine contractions last three to fifteen minutes and happen roughly every 20 to 120 minutes during pregnancy. Although they have a small amplitude (5–15 mmHg), they do lower fetal oxygen levels and cause the release of fetal ACTH. Both breathing and REM sleep are absent from the fetus during these uterine contractions.
Significant psychological or physical stress can cause the body to secrete adrenaline, which lowers blood flow to the placenta and uterus, reducing the amount of oxygen available to the fetus and perhaps impairing development and survival.
Regular immunizations should be completed either before breeding or as soon as possible (depending on the bitch’s region). Early immunity of a puppy depends on the bitch’s immune condition and the absorption of colostrum, which has high quantities of antibodies.

Abortion and parturition inducement

Depending on the stage of pregnancy, all treatments that cause the progesterone to be withdrawn either result in fetal mortality, which is then followed by resorption and/or abortion, or they induce parturition. This can be accomplished by using dopamine agonists, such as cabergoline, to prevent the release of the gonadotropic hormone prolactin during the second part of pregnancy. In a same vein, administering PGF2a at a dosage that causes luteolysis-induced abortions (Johnston et al., 2001)
The antiprogestin Aglepristone® has been successfully used to induce abortions from the time of mating to the final trimester of pregnancy, according to research published in Fieni et al. (1996).
The use of this antiprogestin in conjunction with PGF2a and/or oxytocin has proven to be an effective method for inducing labor; no adverse effects were noted, and the labor process was deemed to be physiological (Riesenbeck et al., 1999).
Myometrial contractions get stronger when calcium is administered and they become more frequent when oxytocin is administered. When the uterine contractions are weak or inefficient, calcium gluconate is administered. By administering it subcutaneously, the risk of cardiac irritation that comes with intravenous administration can be avoided. When uterine contractions are less frequent than anticipated for the stage of labor, oxytocin (0.5–2 U in dogs) is administered. Treatment works best when uterine inertia is developing and contractions are not yet fully stopped. Excessive amounts of oxytocin saturate the receptor sites, rendering it useless as a uterotonic agent. A caesarean delivery is recommended if there is clear evidence of fetal stress (persistent or increasing bradycardia) and if the medicine is not working as intended.

Approaching Parturition and Optional Caesarean Sections

After the LH surge, on Day 63, safe C-sections, whether planned or elective, can likely
be carried out. It is crucial to give special attention to the puppies’ support as there are no reports of clinical studies to back this claim. A spontaneous delivery and avoidance of a caesarean surgery are possible in breeds other than brachycephalic ones if you wait until Days 65 or 66. The timing of surgery in brachycephalic breeds may be significant, even if the prevalence of issues during natural delivery in these breeds is unknown. When done in the US and Canada, elective and emergency c-sections are incredibly safe procedures (Moon et al., 1998).
The concentration of serum progesterone peaks between Days 15 and 30, with values as high as 80 ng/ml (240 nmol/L) and as low as 15 ng/ml (45 nmol/L). Progesterone levels in late gestation, between Days 50 and 60, can range from 3 ng/ml (9 nmol/L) to as high as 15 ng/ml (45 nmol/l). During the 24 hours prior to the start of labor, progesterone usually decreases from 4 to 5 ng/ml to around or less than 2 ng/ml. The pre-partum drop in body temperature began a few days prior to parturition and is best tracked by taking rectal temperature readings twice a day or more frequently. Numerous professionals frequently ask dog owners to take their rectal temperatures two or three times a day beginning one week prior to the anticipated date of whelping.

Management of pregnancy

The most important environmental elements are proper hygiene, the prevention of infectious diseases, the right humidity and temperature levels, and sufficient privacy. For puppies, ambient temperatures of 29.48ºC and humidity levels of 55–65% are frequently advised.
For the dam to construct a nest, bedding is required. It is important to keep other animals in the colony out of the maternity ward to stop the transmission of infectious diseases. Except in cases when the activity is extremely physically taxing, such as racing or hunting, pregnant women are generally free to determine how quickly they exercise and participate in other activities.
Fetal heart rates in dogs that are typical during labor range from 170 to 230 bpm, according to ultrasound data. Near term, normal fetuses are highly active. Stress and hypoxemia cause a decrease in fetal activity and heart rate (Linde-Forsberg, 2005).
Fetal stress is indicated by heart rates of 150–160 bpm. Poor survival occurs when heart rates are less than 130 bpm unless puppies are born in less than two hours. If a pup has a fetal heart rate of fewer than 100 beats per minute, the newborn mortality rate is substantial unless they are delivered right away.
The effective management of pregnancy and the best possible outcomes for the health of the newborn depend on the early detection and treatment of dystocia.

Management of neonate after parturition

The dam must cut the umbilical cord and lick the newborn to remove the fetal membranes as soon as possible after parturition.
In addition to warming and drying the puppy, this promotes breathing. The puppy should subsequently move to the teat and suck as a result of the bitch.
To avoid protracting hypoxia, the foetal membranes must be removed and fluid evacuated from the mouth and nose using a pipette, bulb syringe or dry towel (Davidson, 2003).
Puppies should not be forced to swing in order to clear their airways due to the possibility of brain damage (Traas, 2008).
Neonatal puppies can be revived with the use of oxygen, massaging, and warmth, as well as mild chest compressions and medication.
Following delivery, the umbilical cord can be cut or ripped a further 1cm along its course, or it can be clamped with forceps or ligated around 1cm from the abdomen. The stump should subsequently be treated to stop infection; diluted chlorhexidine solution and iodine tincture have been suggested as effective treatments. In the unlikely event that the dam consumes the treatment while cleaning the puppy, it should be non-toxic (Grandjean et al., 2009).
Providing a suitable nest location, encouraging huddling, making sure the animal consumes enough energy, encouraging huddling and providing external heat sources—though caution must be exercised to prevent overheating—all help lower the danger of hypothermia.
Preventive health care should involve the following: immunizing bitches against canine distemper, parvovirus, adenovirus type II, and influenza before breeding; immunizing pregnant bitches against the canine herpes virus when needed; and deworming pups on a schedule that begins at three weeks of age and is repeated every two weeks using a nontoxic anthelmintic, like pyrantel Pamoate (5 mg/kg PO).
It could be suggested to track feces egg counts in order to reduce newborn mortality (Davidson, 2003).
When dams milk is insufficient or unavailable, commercial milk substitutes are recommended; these should be supplied at 37–38°C according to bodyweight and age.
Beginning at three weeks of age, solid meals can be introduced by combining the milk formula with a high-quality complete puppy food and giving tiny portions four times a day.
It is important to make sure the puppy is not overfed and that food is not being inhaled rather than swallowed. When raising neonates artificially, it is necessary to stimulate the perineal area with moist, warm cotton wool after each feeding to encourage urination and feces. Puppies who are well-hydrated should produce colorless urine (Grandjean et al., 2009).

Conclusions

Being aware of potential issues is a crucial part of pregnancy monitoring. The particular bitch, the genetics of the dam and sire and the kennel husbandry will all influence these. Pregnancy management aims to maximize the health of the dam, fetus, and the newborn to preserve the dams physical state and quality of life during the pregnancy and nursing, as well as to maximize the number of healthy pups that reach the age of weaning. The indicators of a healthy newborn should be easily identified and people in charge of a whelping should be knowledgeable about the husbandry and management techniques needed to give the best possible care and assistance.

References

Bobic Gavrilovic, B., Andersson, K. and Linde Forsberg, C. (2008). Reproductive patterns in the dog—a retrospective study of the Drever breed. Theriogenology.,70:783–94.

Concannon, P., Tsutsui, T. and Schille, V. (2001). Embryo development, hormonal requirements and maternal responses during canine pregnancy. J. Reprod. Fertil., 57: 169–79.

Concannon, P.W. (2000). Canine pregnancy: predicting parturition and timing events of gestation. In: Concannon P, England G, Verstegen J, editors. Recent advances in small animal reproduction. International Veterinary Information Service.

Concannon, P.W. and Verstegen, J. (2004). Pregnancy Management in Dogs and Cats. World Small Animal Veterinary Association World Congress Proceedings, Cornell University, Ithaca, NY, USA; Univ. of Florida, Gainesville, FL, USA.

Davidson, A. P. (2003). Approaches to reducing neonatal mortality in dogs. In Recent Advances in Small Animal Reproduction. International Veterinary Information Service, Ithaca. New York, USA.

Fiéni, F., Tainturier, D., Bruyas, J.F., Badinnand, F., Berthelot, X., Ronsin, P., Rachail ,M. and Lefay, M.P. (1996). Etude clinique d’une anti-hormone pour provoquer l’avortement chez la chienne: l’aglépristone. Rec. Méd. Vét. 172, 359-367.