Fertility is the most essential criterion for the success of the food animal husbandry. Regular and timely conception and calving is very essential for profit oriented dairy keeping.
In cattle, especially in cross bred cattle, many farmers’ experience this unwarranted and loss making condition called Repeat Breeding. In this, cows will come to heat regularly but they fail to conceive after successful mating.
This repeat breeding will incur expenditure by cost of repeated inseminations, cost of management of this condition, cost of feeding without production, loss of milk due delayed conception. We can call a cow “repeat breeder” only when it should have calved early, coming to heat, inseminated with good quality semen but remains unconceived for more than 2 – 3 consecutive times.
Repeat breeding detrimentally affects the cost-effective programme of one calf per year in cows and 2 calves in three years in buffaloes. RBC syndrome is per se a group of sign but the reasons are multiple and combinations.
This condition very commonly observed only in cross bred cattle. Jersey and Holstein cross bred cattle are very commonly affected in our country. Among them also, aged cattle at their 4th or 5th calving are very vulnerable.
But young cow at their 2nd and 3rd calving are not commonly reported for this problem. Successful conception and pregnancy depend on these factors:
- Good plane of nutrition of cow
- Freedom from diseases especially reproductive infections
- Freedom from reproductive tract abnormalities
- Timing of insemination and ovulation
- Good quality, fertile semen or potent bulls
- Correct AI technique & Faultless operator
- Hormonal balance
Reasons for repeat breeding
1. Abnormalities of the reproductive tract acquired during last calving can be a cause for repeat breeding. Cows which underwent abortion / retention of fetal membranes in the previous calving and treated for the same may have acquired some infection in the uterine environment. These infections and corrective treatments can alter the internal environment of the uterus where the embryo should attach itself and survive.
2. In many repeat breeder cows, mild and persistent infections in reproductive tract are commonly observed. Because of these mild degree infections, the internal conditions of uterus go unsuitable for conception and implantation. Moreover, these mild level infections are not easily recognisable as the clinical signs are very subtle.
3. Next important aspect of female reproduction is regularity of oestrus cycle. Healthy cow should show signs of estrum once in every 21 days. Two – three days earlier or later than 21 days is also a healthy cycle only.
That is 17-23 days interval between two consecutive estrum is normal. But in case of repeat breeders with mild uterine infections and early embryonic death, the cycle length is erratic. It may be less than 15 days or more than 25 days also.
If such a short or delayed is observed, those cows should be treated for uterine infections.
4. In the previous calving, if the cow encountered any difficulty / illness, veterinary care should be given at complete level. Insufficient therapy given and incomplete regimen followed will always lead to persistent infection in case of aided delivery.
5. It is well known fact that lean and hidebound animals necessarily suffer due to fertilisation failure. Almost always these energy deficient, lean animals may not exhibit estrum. Even if they exhibit, the signs will be subtle and silent. Apart from energy, protein deficiency, vitamins and mineral deficiencies can challenge the normal reproductive performance of animals.
Vitamin A and E have a major role in fertility. Similarly, copper, manganese, cobalt and selenium have very vital role in fertility. Other vitamins and minerals do have their role in general health thereby on reproduction. Negative energy balance should be addressed first before initiation of any hormonal treatment,
6. Repeat breeding can be a result of sub-fertile / infertile bulls. In villages where breeding bulls are maintained in common, there is every possibility for the sexually transmissible diseases in them. This may spread among the village cows by using these infected bulls. Unfortunately, these sexually transmitted diseases in bulls do not show prominent and recognisable signs.
But they are capable of causing infertility in cows. In artificial insemination, the frozen semen straws used should be of good quality with at least 40% motile sperms. The viability and motility of stored semen sample is principally affected by freezing and thawing, cold chain etc.
Farmers’ role in Management of Repeat breeding syndrome
As the reasons for repeat breeding are of multiple origins, correct diagnosis needs convergence of efforts from farmer / stockman and veterinarian. With concerted and sincere effort by veterinarian, it is very much possible to identify the cause in repeat breeders. After identification of the reason, the role of farmer is equally important like that of veterinarian.
Correct observation of cow : Animals which are deficient in micronutrients tend to express mild signs of estrum. These types of silent and subestrus animals should be given extra attention. Besides that, the nature of discharge, colour of discharge, onset time, various signs and behavioural changes, duration of heat should be observed.
Correct reporting of previous gestation history: The treatment and management procedures for repeat breeding rely upon the history of previous gestation and oestrous cycle. In order to give correct information to the veterinarian, a farmer is to be watchful and attentive.
The farmer is expected to adhere to the timing and treatment protocol suggested by the veterinarian.
Avoiding farm-side treatment of obstetrical and gynaecological disorders. Farmers frequently attempt to solve the crisis of obstetrical problems with their traditional knowhow.
But this practice cannot always be free of complications. In every aspect of obstetrical manoeuvre, antisepsis is to be strictly adhered. Hence it is not at all advisable to do attempt these sorts of issues at farmer level of knowledge.
In semi-intensive systems of rearing, every effort should be made to provide a balanced, good quality and quantity feed is needed. This is warranted because many micro nutrients and minerals are not available in required in regular feed stuff. Supplementation with minerals and vitamins are very essential.
Animals which were not routinely dewormed and vaccinated usually got a serious infection. This diseased animal does not usually perform better in reproduction. Healthcare activities like deworming and vaccination
- History of feeding, breeding, health, age, breed, previous inseminations, methods of insemination, inter-oestrus interval, duration of estrum, nature of discharge, mounting behaviour, previous treatments if any, milk yield, previous calving history, past complications, etc
- The external genitalia viz.. vulva, vestibule, vagina should be carefully examined to note the abnormalities. Vaginal discharge is a good indicator for uterine health status. A complete vaginal examination with the aid of speculum and flash light will be of use for diagnosing clinical endometritis. Gloved hand examination of vagina will also be suitable in diagnosing endometritis. Ultrasonography is also recommended but it is less sensitive for the diagnosis of endometritis. Closed pyometra can easily be diagnosed using transrectal sonography.
- The oviduct occlusion / block can be an underlying factor for repeat breeding. In such a case, special techniques like phenosulphonpthalein dye test (PSP) are to be used. Special procedures like PSP dye test and sonography could be used effectively to ascertain the cause of RBC syndrome.
- Microbiolgical examination of cervical and uterine fluids is affected animal will narrow down the causative agent in case of mild and persistent infections.
- Histopathological examination of uterine endometrial biopsy specimens- isolation of bacteria from uterine discharge and cervical mucus is not considered as sensitive for the diagnosis of subclinical endometritis. But, cytoanalysis, endometrial biopsy could be a more accurate than the bacteriological culture. Cytobrushes and endometrial biopsy forceps are very commonly and efficiently used in herd management.
- Hormonal assay in delayed and mis-timed ovulations- luteal deficiency causing RBC syndrome can be diagnosed by estimation of progesterone in serum / milk.
- The deficiency of micronutrients and certain vitamins compromise the fertility. Analysis of deficient nutrients like Cu, Co, Mn, P, Zn, Se in repeat breeders would be of diagnostic utility. In field situations, common practice of administering micromineral supplements is encouraged and fruitful.
In general, diagnosis of repeat breeding is a challenging task. But the treatment and therapeutic response are positive on many incidences. Traditionally, there were antibiotics, antiseptics, hormones, micronutrient supplementations and herbal remedies were attempted. But the targeted therapy involves right diagnosis of the cause.
In the recent decade, uterine lavage with normal saline and hypertonic dextrose (50%) solution gain popularity and advocacy. In repeat breeding cows with endometritis, infusion of 300-400 ml of isotonic saline into the uterus claimed to have advantage of good cellular response.
Some studies describe the use of hypertonic dextrose also. Infusion of ozone into the uterus is a new treatment option in uterine infections. Antiseptics do not create the issue of milk residues; but many are irritants; previously, iodine preparations like polyvinyl pyrrolidone (Povidone®) were used for the treatment of uterine infections in cattle.
But in recent reports, it was noted that the irritant nature of iodine preparations potentially damage the endometrium and reduced the conception rate in forthcoming estrum. Many studies support this view of replacing the antiseptics with intrauterine antibiotic preparations.
For clinical and subclinical endometritis, many commercial preparations are available. But ceftiofur sodium @ 2.2mg/kg is the only recommended.
It has the added advantage of attaining Minimum Inhibitory Concentration in uterus rapidly and furthermore it is effective against common uterine pathogens like Escherichia coli, Trueperella pyogenes, Fusobacterium necrophorum and Prevotella melaninogenica are the very common isolates in uterine infections. In the post-partum uterine environment, these four organism work in synergy to brought about metritis.
Tetracyclines are irritants. Aminoglycosides and sulphonamides do not work in the presence of purulent material. Many antibiotics are not permitted to be used as IU owing to long milk withdrawal period.
Parenteral administration of antibiotics is advocated in the recent years after the awareness of antibiotic residues in milk. In Indian commercial market, cephelosporins are available as intra-uterine medication.
For repeat breeding due to uterine infections, prostaglandins can be used at 13 days apart. But presence of functional CL is essential. Usage of PGF2 alpha as a prophylactic measure for metritis in post-partum situations is not advantageous.
Combination of uterine lavage with PGF2 alpha is preferred for treating endometritis with overwhelming advantage of zero-antibiotic residue and zero-withdrawal period. Oxytocin is also used but in limited circumstances.
Dry matter intake is the single most influential factor for reproductive health. Especially in transition period, all out effort is to be made to maintain the energy balance positively. Negative energy balance could provoke a cascade of metabolic reaction lead to ketosis, abomasal displacement and fat deposition in liver.
Ketosis and hypocalcemia are very important precipitating factors for post-partum uterine infections, ROP, dystocia etc. Recents trend of feeding anionic diet could prevent the occurrence of hypocalcemia but it should be accepted that anionic feed is not without risk. Anionic diets are not advisable for farm situations where Dietary Cation- Anion- difference (DCAD) is not practically calculated.
Feeding monensin and rumen protected choline are proven prophylactic measures against ketosis, mastitis and later on indirectly on uterine health.
Microminerals are beneficial although some controversies cropped up wherein supplementation beyond the content in feed. But the indisputable roles of micronutrients like Se, Zn, Cu, and Mn and vitamins A and D have been proved again and again.
For instance, supplementation of 3000 IU vitamin E/cow/day in late gestation prevented occurrence of uterine diseases. Similarly Se is allowed to be incorporated in feed at the level of 0.3 ppm (mg/kg DM) only to harvest the good effects on fertility.
Considering the bioavailability, organic trace minerals (e.g: selenium yeast) are preferred over inorganic one (eg: sodium selenite).
This Repeat breeding in cows plays havoc in small scale dairy farming. As all diagnostic and therapeutic options for treating the RBC syndrome have not percolated into the field situations, large number of repeat breeders in rural and remote parts of the developing countries has not been attended.
Large scale dissemination of knowledge and tools to handle this problem at farmer’s doorstep is need of the hour. Empowering the field veterinarians with updated diagnostic and therapeutic options will certainly bring about a remarkable change in scenario.
Restoring the fertility in repeat breeder cow can be accomplished by synergistic and concerted efforts of farmer, veterinarian, policy-makers and other stakeholders.
Jegaveera Pandian, Pankaj Kumar, Asit Chakrabarti and Pradeep Kumar Ray
Division of Livestock and Fisheries Management,
ICAR Research Complex for Eastern Region, Patna- 800 014, Bihar