Congenital Affections in Bovine
Congenital Abnormality is defined as defect in structure and function, which are present at birth . Congenital malformations can result from defective genetics or environmental factors or a combination of both and are mainly by virtue of autosomal recessively inherited genes .Congenital arthrogryposisin calf has also been reported by ingestion of plant genus Lupinus by pregnant cows and infection by viruses of the family Bunyaviridae . But still the cause of many congenital defects is unknown. Congenital abnormalities occur more in animals during 4–8 weeks of foetal life .Recognized environmental factors include nutritional deficiencies, teratogenic drugs or chemical exposure, some viral infections, toxic plant ingestion, x- rays and per rectal examination during the early stage of organogenesis . Most of congenital defects need immediate surgical intervention while some congenital defects get importance at the time of production or reproduction. These include affections of teat and vagina (persistent hymen). By restricting the breeding of animals with congenital surgical condition that have complete surgical treatment like umbilical hernia, previous urachus etc, can reduce incidence of congenital affections in subsequent progeny. However, inheritability of any condition should be ascertained. Animals with congenital defects should not be bred but their survival can be improved by timely surgical intervention.
Congenital affections are commonly encountered in calves.
Few abnormities are major and lead to death of the calf soon after birth but many survive little longer and few even live a normal life. The article describes the common type of congenital affections presented in the calves of cow and buffaloes and there surgical correction, if any.Congenital defects are the abnormalities, which are present at birth and can be structural, functional or both. Majority of the abnormalities are minor but certain may be related to more than one organ due to the same developmental germ layers and are life threatening. Genetics and the environment in the pre-natal stage may be responsible for these abnormalities. The incidence of congenital defects ranges from 2 to 3.5% of all births in calves, lambs and foals . Congenital abnormalities occurs maximum in animals during 4–8 weeks of foetal life. There can be many causes for the occurrence of congenital defects, a few are listed below:
• Hereditary/genetics • Ingestion of toxic plants by the bovine during gestation. • Environmental factors like nutritional deficiencies, teratogenic drugs or chemical exposure, viral infections, • X- rays and per rectal examination during the early stage of organogenesis. (Rafid, 2010) The various types of common congenital defects are being described below:
- Atresia Anai, et recti, et coli
Atresia anai alone or et recti or et coli are common congenital gastro-intestinal malformation in large and small ruminants. The condition may occur alone or with agenesis of other parts like vagino urethral agenesis hypospadias, cleft scrota. Probable aetiology: Rectal palpation before 40 days of gestation (Durmus 2009).
Clinical signs: absence of anal opening (Fig. 1), suspended defecation. In atresia anai alone, a bulge is felt and seen at the site of anus when the calf strains to defecate or abdominal pressure is applied manually (Singh et al. 2020). Surgical treatment: Surgical formation of anus can be done under local infiltration anaesthesia in 1-2 day old calf. A X or Round incision of 2-3cm (Singh et al., 2020) is made below the base of tail where bulging is most prominent. The blind end of rectum is identified and opened and confirmed with meconium coming from it. The rectal wall is sutured with the skin at four cardinal sites and if required diagonal also using nylon or silk in interrupted fashion. A syringe barrel of 20 ml may also be placed and sutured with anus outside for few days. Major complication: Stenosis of anus.
2.Umbilical hernia
Umbilical hernia is the most common form of congenital hernia in calves and many umbilical hernias are secondary to umbilical sepsis (Fig. 2). Etiology: Umbilical hernia is common in females than males and is primarily hereditary in origin due to dominant gene with low penetrance, autosomal recessive genes or due to environmental factor (Singh et al., 2020). Inflammation and sepsis of the umbilicus, post-calving infection of umbilical infection, breakage of the umbilicus during manual traction of the foetus, external trauma to the umbilicus, excessive straining, cloned calves (less collagen in the ventral abdominal wall), hypoplasia of the abdominal musculature, and multiple births (twins, triplets, etc). Surgical Treatment: • Close the hernia ring by vest over pant sutures using sterile silk thread (no. 2, double). • The calf should be dorsal recumbency to allow least pressure on the suture line and to avoid interference of the abdominal organs. • In young calves on milk diet, the surgery can be done without keeping off feed and off water under local (total 5-7ml) and sedation (inj. diazepam (@0.2mg/kg) and inj ketamine (@4mg/kg), IV), if required. • In adult calves/cows/heifers, as per the status of feed, may need off feed and off water for 12, 24 or 36 hrs. General anaesthesia is required to place the animal in dorsal recumbency. Major complications: reoccurrence/infection, if sutures are not applied properly or are loose.
3. Pervious urachus
The most common congenital condition of the urinary bladder is the pervious urachus. This condition is more commonly observed in the foals, cow calves and is rare in buffalo calves (Sharma and Singh, 2004). Etiology: In pre-natal life, the urinary bladder communicates with the allantois through urachuswhich becomes atrophied and itslumen gets obliterated after parturition.Complete failure of urachal lumen obliteration throughout its length results in development of pervious urachus. • The disorderissometimes accompanied by urethral obstruction and uroperitoneum and thus may deteriorate the animal condition and may become life threatening. Clinical signs: The young one shows dribbling of urine from the umbilicus and the area surrounding it remains wet. The young one may pass urine from normal site or may not pass. Treatment: Both surgical and conservative treatments are indicated (Singh et al., 2020). Conservative treatment is successful in initial stages or when the condition is partial. A cotton swab dipped in 90% phenol is applied inside the urachus at a distance of 4-5 centimetres towards the urinary bladder. • The surgical treatment is required when conservative treatment fails or the urine dribbling from the umbilicus is high. The abdomen is opened at umbilicus and the vessels and the urachus is ligated with absorbable sutures. The surgery can be done like umbilical hernia. Necrotic tissue, if any, needs to be removed.
4. Contracted tendon
It is a congenital deformity of locomotor system and is commonly observed in calves, lambs and foals and affects flexor and extensor tendon of fetlock and pastern joints (Sangwan et al. 2009). The tendon disorders may be congenital or acquired. Congenital abnormalities include lax tendons, contracted tendons, and displaced tendons. Acquired tendon disorders include lax tendons, contracted tendons, luxated tendons, tendinitis, lacerated tendons, avulsed tendons, ruptured tendons, and tenosynovitis. Etiology: One school of thought says that the in-utero mal-positioning and overcrowding caused by size of the foetus relative to the dam may lead to contracted tendon condition. But other school of thought is that the condition is due to autosomal recessive gene. Clinical signs: At birth, the young one is unable to bear weight on affected limbs due to shortening of superficial and deep digital flexor tendon and associated muscles at fetlock and pastern region. In case of contracture at fetlock, the calf may bear weight on the anterior aspect of fetlock, leading to development of wounds and in chronic case may lead to opening of joint. Treatment: • Mild cases may not need surgical corrections and a bandaging with a caudal aluminium splint may be done to keep the limb straight. The bandaging and splint need to involve fetlock and carpal in case of fetlock joint. When the calf will put weight on the hoof, the condition will improve more. • Surgical correction includes partial or complete tenotomy of the superficial digital flexor and deep digital flexor tendon is done depending on severity of knuckling. They are usually cut under local infiltration anaesthesia at the distal third region of metacarpal in case of fetlock contracture. The tension in the tendon can be felt. With manual pressure the limb is straightened and POP is a pplied with a caudal and cranial aluminium straight splint (Fig. 3). The fetlock and carpal joint need to be involved. Antibiotics and pain killers are given and the pop may be repeated after one week. Complication: If contracture is severe, the limb may get rotated. The tarsal contractures may not be possible to be corrected.
5. Cleft palate
Clefts of the face are the developmental disorders resulting from a failure of closure in facial processes such as the fronto-nasal, maxillary (Fig. 4), and mandibular processes. Etiology: Primary cleft palate is due to incomplete fusion of fronto-nasal prominence with the maxillary prominence, whereas the secondary cleft palate is due to incomplete fusion or failure of fusion between the lateral palatine processes. The incidence of cleft palate in cattle is estimated to be rare. Clinical signs: Postprandial bilateral nasal discharge or milk, coughing and dysphagia are the usual clinical signs that can be observed at birth or after suckling has commenced (Smolec et al., 2010). Treatment: Surgical correction of the defect may be tried under general anaesthesia in cases with mild to moderate defect. Severe cases are difficult to treat. Complications: Suture dehiscence with re-occurrence
6. Hypospadias
Hypospadias is a rare congenital malformation of the urethra reported in dogs, sheep, goats, cattle, rats, nonhuman primates and humans. Clinical Sings: In hypospadias the urethra may open anywhere along its length at one or more locations from the perineum to the tip of penis and is often accompanied by the hypoplasia of the corpus cavernosum urethra (Alam et al., 2005). Etiology: It is due to incomplete formation of the penile urethra and imperfect closure of the external male urethra (Radostits et al., 2007). The disturbance in the process of fusion of the paired urethral folds to form complete urethra after rupture of the urogenital membrane (Kluth et al., 1988) or extra/intrauterine factors resulting in abnormalities of androgen metabolism and timing of receptor function during male sexual differentiation at the early period of gestation (Uda et al., 2004) may be the reasons for this defect.. Treatment: • Surgical correction is not recommended if it co exists with other anomaly (Singh et al., 2020). Perineal urethrostomy can be done, if required.
7. Ocular dermoid cyst
The ocular dermoid cyst may be solitary or multiple, firm to fluctuant, well circumscribed, smooth, and round and usually the overlaying skin is normal (Fig. 5). Etiology: Dermoid cysts are formed due to defective epidermal closure along embryonic fissures, which isolates an island of ectoderm in the dermis or subcutis. The cyst usually contains hair, keratin, and sebum, and these materials may produce progressive enlargement of the structure so that it becomes clinically apparent (Edwards, 2002). Clinical signs: Hair are seen on the cornea or limbus mostly which irritate eye leading to watery discharge initially. Treatment: Surgical removal of hair projections along with superficial lamellar keratectomy is recommended under auriculopalpebral and Peterson nerves blocks.
8. Supernumerary Teat
Supernumerary, or extra teats in ruminants are defined as any teat that is in excess of the normal number of teats (Fig. 6). The extra teat is usually blind but may sometime have streak canal. Treatment: The surgical excision of the extra teat is recommended under local infiltration anaesthesia before getting pregnant for the first time. This is not recommended for con-joint teat.
9. Polydactyl
Polydactyly is an abnormal condition in which cattle are born with one or more extra digits on one or more limbs (Fig. 7). It has been reported to be sex-linked recessive gene with males expressing the trait with one gene but females requiring two genes (similar to the inheritance of red-green colour blindness in humans). Treatment: Surgical excision of the extra digit is recommended from the base at an early age to avoid deformity in normal digit.
10. Dentigerous cyst
The dentigerous cyst is a malformation derived from deciduous and/or permanent teeth follicle and cell rests in the dental lamina. Dentigerous cysts consist of osseous tissue like enamel, cementum, dentin and pulpal tissue (malformed tooth/ teeth-like structures). Etiology: During embryogenesis, the maxillae, mandibles, and muscles associated with chewing develop from the first branchial cleft and the teeth develop from the epithelium of the oral cavity and blend with the periodontium, cement, and dental papilla, which are derived from mesenchymal tissue (Schnorr & Stuttgart, 2001). Clinical Sings: Swelling in the mandibular or maxillary region(s) of the head with discharge may be noticed.. Treatment: Surgical excision of the bony structure under general anaesthesia is recommended with complications of infection and reoccurrence.
11. Wry tail
It a genetic variation in domestic cattle in which the base of the tail is distorted and the tail partially turned to right or left. The defect may also be associated with congenital heart defect, so echocardiography is recommended. No treatment is required for tail.
12. Hydrocephalous
Hydrocephalus is an accumulation of excessive fluid in durameter or ventricles of the brain thereby leading to the swelling of the cranium. Aetiology: Abnormal development of the fetus during pregnancy; hereditary, infectious, and nutritional factors may predispose. Occasional in the ewe, doe, mare, and sow, and rare cattle and buffalo (Long, 2001). Clinical Signs: Hydrocephalus may cause increased intracranial cerebral pressure, progressive enlargement of the head, convulsions, mental disability, and even death (Saini et al., 2019). The life span of the affected new born is less.
Compiled & Shared by- Team, LITD (Livestock Institute of Training & Development)
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