Retention of Placenta in Dairy Cows and its Economic Impacts on Reproduction
Jitendra kumar1, Shivika Chouksey1, Poonam Yadav2, Preeti Verma2
- Department of Veterinary Gynaecology & Obstetrics Jabalpur
- Department of Veterinary Physiology & Biochemistry Jabalpur
College of Veterinary Science and Animal Husbandry Jabalpur,
NDVSU Jabalpur M.P-482001
Corresponding auther: jitendrasingh263@gmail.com
Introduction:
Foetal membranes are also known as “placenta” is an essential organ for prenatal transfer of nutrients and oxygen from the dam to the foetus. The normal separation of foetal membranes consists of complex hormonal process that starts before parturition in cows, which drops within short time after birth. If the placenta is not expelled within certain time (12 h post calving) it is defined as being retained placenta (RP). It’s a condition where all or part of the placenta or membranes are left behind in the uterus during the third stage of labour. Retained placenta creates a number of problems following pulling of microorganisms into the uterus causing its inflammation, decreased milk yield, longer calving intervals, reduction of fertility, longer calving interval, and reduce conception rate. Retention of placenta causes great economic losses, mainly due to decreased milk yield and loss due to infertility.
Etiology
The causative factors are:
Infectious disease:
Infectious disease causes of placental retention are behind the scope. Infectious diseases like Bovine Viral Diarrhoea may cause RFM in cattle. Brucellosis is a contagious bacterial disease of sexually mature animals and causing abortion and retained placenta .The disease is clinically characterized by abortion in the last trimester and retained placenta in the female whereas orchitis and epididymitis in male.
Managemental:
Managemental causes of retained placenta include stress hereditary, inbreeding and obesity. Lack of exercise and hypocalcaemia are the most frequent causes of decreased myometrium contractility. Stress (Transportation, rough handling, poor feed conditions, Isolation from group, Lameness,) results in elevated corticosteroids and increased risk of placental retention. Dairy producers have suggested that Poor health management in herds can predispose animal to retention of placenta. In addition to this deficiency of antioxidant, vitamin E and selenium may decrease chemo taxis and leukocyte numbers at the feto-maternal junction, thus contributing to the retention of foetal membranes. Over-condition and under condition as well as managemental defects and environmental factors can result in retention of placenta.
Nutritional:
Nutritional causes of RP are primarily due to the deficiency of feed during the last 6 to 8 weeks before calving specially when there is deficiency of content of minerals and vitamins in diet. Heavy grain feeding may be associated with both higher milk production and increased risk of reproductive disorders such as dystocia, retained placenta, cystic ovaries, metritis other reproductive disorders. Vitamin and mineral deficiency conditions such as selenium, vitamin E and vitamin A, B-carotene and disturbed Ca/P ratio can impair general immunity and may alter the competence of cellular self-defence mechanism and can increase the risk for placental retention and metritis. High milking cows with a greater degree of negative energy balance pre-partum and higher NEFA concentrations were more likely to suffer from retention of placenta. On the other hand, over conditioned cows were shown to be more sensitive to retained placenta and subsequent infertility than cows with normal body condition scores
Body weight of Cow’s and Calves’
Retention placenta increases significantly with increasing live body weight of cows due to the increment in fat adipose tissues, which may result in trapping the steroid sex hormones. A significant increment of retained placental problem is happening with increasing foetal birth weight. The reason could be due to pressure of the foetus on the placenta and foetal membrane, so that the attachment between the cotyledons and the foetal membrane become stronger these consequent in occurrence of placental retention
Failure of maternal Immune Response:
It is occurred due to failure of the maternal immune system to successfully degrade the placentomes at the end of pregnancy. Maternal immunological recognition of foetal MHC class I proteins expressed by trophoblast cells triggers an immune inflammatory response that contributes to placental separation. This lymphocytic activation was suppressed at the foeto-maternal interface alongside the pregnancy course to avoid rejection of fetal allograft where the trophoblast secretes interferon-tau (IFN- t) and both trophoblast and endometrium secrete prostaglandin E2 and the endometrial glands secrete serpins (uterine milk proteins), all of which inhibit lymphocyte activation to keep on the embryo not rejected by the dam.
Hormonal disturbances:
Placental separation occurs when foetal cortisol induces the production of the enzymes, 17-hydroxylase and aromatase in the placenta which favour oestrogen synthesis at the expense of progesterone synthesis. Maternal plasma levels of oestradiol increase suddenly, while plasma levels of progesterone decline sharply immediately prior to parturition. It is supposed during the week before parturition, the level of estradiol reaches its maximum level to help the uterus to get rid of any remnant of foetal membranes. Therefore, a decreased level of oestrogen may be indicated as a factor enhancing retention of placenta. Spontaneous myometrial contractility is augmented by autocrine and paracrine release of PGF and parturition ensues. Disturbed endocrine function high progesterone and cortisol levels and low oestradiol level was traced in the blood cows with RP. Increased progesterone level in RP may be due to failure of the placenta to produce specific steroidal enzymes that help in progesterone aromatization and its conversion to oestrogen.
Mechanical Causes of Retained Placenta:
Difficult birth (calf too large for cow, backwards calf known as breech birth, one leg or head backwards), twins, late or premature birth, prenatal loss, induction of parturition with PGF2 , caesarean section and fetal monsters or emphysematous foetus are direct causes of dystocia and consequently to retention of placenta.
Failure of cotyledon-caruncle detaching mechanism:
The main cause of retained placenta is due to a lack of breakdown of the caruncle-cotelydon attachments after delivering the foetus. The reasons could be due to infectious and/or non-infectious factors. Primary attention has been often directed to infectious causes, but non infectious factors probably account for 70% or more of the cases. Non-infectious causes are often multi factorial and are difficult to diagnose.
Reproductive Impact of Retained Placenta:
The fertility of the dairy cows is affected when most cows in the herd suffer from retained placenta. These causes direct loss to the farmer due to delayed calving leading to a lengthy period between births (calving intervals) and hence low milk production. The adverse effects of RFM on reproductive performance of cattle are delay in first service, reduction of pregnancy rate, and increase in services per conception. The RFM also leads to endometritis, puperal metritis and mastitis. And these diseases ultimately cause the reduction in the fertility and milk production of cattle.
Mastitis:
Although the main economic impact of ROP seems to be decreased milk production, more days open, decreased milk volume, the correlation between ROP and mastitis is controversial. However, the economic losses as a result of mastitis could be due to reduced milk production, discarded milk, reduced cow sale value, drugs and veterinary services. It is unhygienic to milk a cow with decomposing afterbirth hanging on it.
Metritis:
Retention of placenta and metritis are positively correlated. Cows with ROP had a significantly higher incidence of metritis than cows without ROP and also a significant difference was found between conception rates in cows with ROP and metritis. Retention of placenta results from the presence of decomposing placental tissues, which provide a favorable environment for bacterial colonization. Coliform bacteria and high concentrations of endotoxins present in lochia of cows with ROP are potent inducers of prostaglandins and cytokines, favouring development of uterine infections. Metritis result in decreased dry matter intake, and hence, multiparous cows with metritis in early lactation produce less milk than the healthy cows. This difference is greatest during the first 20 weeks of lactation.
Economic Losses due to infertility and low milk production:
Retained placenta, one of the main causes of endometritis in cattle, causes economic loss. In dairy cows retained placenta may be the cause of serious economic losses to the farmers as cows with retained placenta may develop bacterial infection and become ill and thus reduce production. Some may even die. Milk from cows with retained placenta is unfit for human consumption and therefore cannot be sold. The fertility of dairy cows is affected when most cows in the herd suffer from retained placenta. This causes a direct loss to the farmer due to delayed calving leading to a lengthy period between births (calving intervals) and hence low milk production. The retained fatal membrane causes considerable economic loss, especially when incidence exceeds the average of 5-10%. The fertility of cows after retention of the placenta appeared to be affected. Generally, retention of placenta has great influence on productivity. For instance, retained placenta had a significant negative effect on milk yield for several weeks after calving and there is considerable milk loss as a result of difficult of calving.
Increased postpartum anoestrus interval:
Placental retention causes delayed involution of the uterus, and adversely affects reproductive performance]. Cows with reproductive disorders had longer intervals from calving to first service and to conception and required more services per conception and lower pregnancy rate and conception to first service]. The period from parturition to the first service was longer in cows exhibiting retained placenta compared to normal ones
Longer calving interval:
Retention of placenta may cause prolonged calving interval and permanent infertility. Calving interval remained longer in cows revealing retained placenta as compared to normal cows. In general, the financial losses due to retained placenta in dairy cattle existed due to increased calving interval, increased culling rate, reduced conception rate, infertility, loss of milk production, the costs of veterinary service and drugs
Reduce conception rate:
Varies studies reported that the conception rate of cows presenting retained placenta were significantly lower compared to normally calved cows. The highest proportion of normal cows was conceived during the period from 61 to 90 days after parturition, while cows with retained placenta were conceived at more than 120 days after parturition
Treatment:
It is important to clearly establish the objective of RP treatment. Many antimicrobial and hormonal treatments have been applied to cows with retention of placenta. Tetracycline antibiotics commonly used for intrauterine treatment in cattle, inhibit MMPs and might therefore interfere with the normal placental detachment mechanisms.
Daily intrauterine (IU) infusions of 5 g oxytetracycline for as long as the RP is in place reduced the incidence of fever from approximately 50% of cows with RP to approximately 30% of affected cows. Ceftiofur sodium also uses @1.1 mg/kg IM q 24 h for 5 days.
Many indigenous preparations are available in the market for removal of retained placenta for example Uterotone liquid, Uterifit, Involon etc. One of these should be used for the expulsion of retained placenta as well as these assist in manual removal of placenta in the condition when normal expulsion is failed after this treatment. Use @ dose of 200 ml. on the first day followed by 100ml. for 3 consecutive days.
The hormones which are used for treating retention of fetal membranes or retained of placenta are Prostaglandins and oxytocin. These hormones play a role in uterine contraction and could be effective in treating retention of foetal membrane because of uterine atony. Use of oxytocin is of questionable after 24 hours of calving because by this time, the response to oxytocin becomes poor.
If normal expulsion of placenta fails even after the treatment with drugs, then the placenta should be removed manually. After manual removal of placenta, 4-5 boli of suitable intrauterine preparations should be kept in the uterine horns. Many intrauterine preparations are available in the market. These are Furea, Lixen IU, Povidone iodine bolus, Cleanex etc. One of these should be continued for 3 to 5 days in suspension form i.e. infuse the prepared solution in the uterus with the help of a catheter.
Prevention and control:
The control of retained placenta needs to focus on the control of causative factors like abortions, premature calving, calving difficulties, and vitamin and mineral deficiencies. Milk fever and even sub-clinical calcium deficiency can be associated with an increased risk of RFM with older cows more at risk of lower blood calcium. Then it needs to be controlled. Good control of feeding and condition during the dry period and avoiding cows becoming over fat will also reduce the incidence of retained placenta. The herds with a history of selenium deficiency had a high incidence of retention of foetal membrane, and according to their suggestion supplementation of vitamin E and selenium can help to reduce placental retention. The synthetic form of vitamin E (alpha-tocopherol acetate) was found to be more effective than the natural form of vitamin E. Supplementation with balanced vitamin and mineral mixture in pre-partum period is considered a prophylactic step to avoid foetal membrane retention. Although these vitamins and minerals can be supplemented, correct pasture based diet formulation could prevent the need for additional supplementation. The infectious diseases can be prevented by proper immunization against specific infection.
