Flashcards in Bovine Deck (459)
How is local anaesthetic used for castration?
Inject 3-5ml proacine under the scrotal skin and into the testicle. General anaesthetic is only considered for mature bulls or complicated cases e.g partially retained testicles, inguinal hernia etc when standing surgery is not possible.
What complications are seen in surgical castration?
Haemorrhage - when vascular portion of cord is snapped off close to the testes. These calves often develop a large scrotal haematoma.
Gut tie is rare complication of surgical castration of older calves - the remnant of the ruptured spermatic cord/ductus deferens recoils into the abdomen and can become adherent to abdominal wall or viscera causing a slow onset mechanical obstruction of the bowel.
What should you do if you are presented with a rig calf?
Crypotorchid calves should not be unilaterally castrated as the remaining testicle may descend at a later date and the bull calf become fertile. Cryptorchid calves should be left entire and reared as bulls.
How is bloodless castration done with burdizzo?
Should be carried out before 2 months of age otherwise local anaesthetic is required. Pull down on testicles to get access to the neck of the scrotum. the burdizzo clamp is applied twice across each side of the spermatic cord taking care to stagger the position of the crushing. The clamps cause crushing of the spermatic vessels which leads to ischaemic necrosis of the testicles over the following weeks.
Describe vasectomy technique in rams?
Ram is positioned on its hindquarters or in dorsal recumbency following sedation and local anaesthesia or preferably lumbosacral epidural anaesthetic. Incision is made in the skin over the spermatic cord a tthe level of the accessory teats. The spermatic cord is exteriorised following blunt dissection with finger or forceps and the vas deferens localised. The vas deferens is ligated twice and section between the sutures removed. During closure the ligated ends are incorporated in different fascial planes to further reduce the possibility of re canalisation.
At what age can you disbud a calf without anaesthetic?
chemical paste can be applied
What nerve block should be used for disbudding in cattle?
Cornual nerve block using 2-4 ml procaine each side. A useful tip when dehorning large beef calves is to add 3-4ml of 2% xylazine injection to a bottle of 100ml local anaesthetic, gives mild sedation which aids in restraint and calms the cattle.
What complications can occur following dehorning?
Haemorrhage form the nose is often seen immediately after dehorning and is simply due to blood running through the sinuses and draining into the nasal cavity. Rarely, fatal haemorrhage form the cornual artery bleeding can occur following dehorning of large calves so calves should always be checked for arteries spurting. Sinusitis is occasionally seen in older cattle after dehorning. Cattle may appear dull and reluctant to feed at barriers . Tx by flushing with dilute iodine and systemic antibiotics.
What are the differences in disbudding goat kids compared to cattle?
Goat kids have a much larger area of horn bud relative to calves and the horn grows rapidly necessitating early disbudding. Ideally a short acting general anaesthetic is given which can be supplemented by local anaesthetic. Maximum 1ml 2% lignocaine pe kid to prevent toxicity. Skull is much thinner than calves and overheating can cause brain damage so iron must only be applied with gentle pressure for short periods only.
How are bulls nose ringed?
All mature stock bulls should have nose rings inserted to aid handling. light sedation with xylazine may be required. Local is injected with a fine needle into septum. The septum is punctured just cranial to the cartilaginous septum using a leather punch or trocar before pushing the sharp end of the open ring through the defect.
What are the most common serovars of leptospira in the UK?
Leotpspira borgpetersenii serovar hardjo.
Leptospira interrogans serovar hardjo.
Rarely infection with leptospira pomona or leptospira icterohaemorrhaghica occurs in cattle giving a severe often fatal septicaemia associated with pyrexia, jaundice, haemoglobinuria etc.
How does infection with leptospirosis occur?
Infection follows bacterial penetration of mucous membranes/skin. In non immune lactating or pregnant animals rapid multiplication in uterus or udder is followed by bacteraemia. BActeraemia persists for 6-9 days unutil humoral antibodies appear in blood. Leptospira organisms can persist after initial bacteraemia in CNS, reproductive tract and kidneys.
How is leptospirosis shed?
Renal shedding of leptospires in urine occurs after about 14 days and may persist for months or intermittent shedding may occur for years.
What is the route of transmission of leptospirosis?
Infection arises from contact with infected urine or from water/pasture contaminated with urine. Products of abortion are also sources of infection. Most spread probably occurs in spring/summer at pasture. Venereal transmission is possible from bulls carrying lepto in accessory sex glands etc.
Which other animals carry leptospira hardjo?
Leptospira hardjo are not carried by vermin/wildlife. Sheep can also carry and excrete leptospira therefore farms with mixed grazing are more at risk.
What are the clinical syndromes seen in leptospirosis infection in cattle?
Milk drop - occurs 2-7 days after initial infection of a non immune cow. Get a sudden reduction or cessation of yield. May get t hick colostrum like, blood tinged milk in all quarters. Udder goes soft and flabby.
Abortion may occur 3-12 weeks following infection . Most abortions occur in last trimester. May also get weak /premature calves born.
Infertility - circumstantial evidence of infertility caused by lepto in reprotract.
How is diagnosis of leptospirosis made?
Microscopic agglutination test used to detect antibodies to lepto hardjo in serum and more recently this is being replaced by an ELISA. Big variation in individual antibody response and duration of MAT titres. Carrier animals may have negative MAT titres. Paired serum samples taken 3-4 weeks apart will normally demonstrate seroconversion.
What tests can be performed on aborted foetus' to diagnose leptospirosis?
Antibodies in foetal fluids - may indicate exposure to lepto in utero after period of immunocompetence >4mths. Foetus may die before mounting an immune response.
Fluorescent antibody test - to detect lepto antigen in foetal tissues eg kidney li& liver. Delay in submitting samples may lead to pm decomposition of lepto.
How can the herd be screened for leptospirosis?
Need to screen about 25% of herd. A milk elisa is available for bulk milk screening. If only a few seropositive animals with low tites then may indicate historical exposure of older cows. If several cows seropositive with some high titres then may indicate active infection in herd.
What is the treatment of leptospirosis?
Streptomycin/dihydrostreptomycin single dose im will probably eliminate infection in most cases. Oxytetracycline or amoxycillin also likely to be effective.
How can leptospirosis be controlled/prevented?
Control of lepto in cattle herds relies on a combination of management decisions, antibiotic treatment and vaccination. Two killed adjuvanted vaccines are available in the uk, leptavoid-H and spirovac. Vaccination should prevent urine shedding and will protect against milk drop and abortion
What control strategies can be used for a closed herd to prevent leptospirosis ?
Avoid mixed grazing with sheep and fields with shared water courses, ay additions to breeding herd including bulls should be isolated for 3 weeks and treated with streptomycin twice days 10-14 days apart before entry.
What control measures should be used for a herd experiencing acute infection with leptospirosis for the first time?
Consider whole herd antibiotic treatment to reduce risk of spread of infection and zoonotic risk. Start vaccination programme for whole herd. Bought in replacements should be vaccinated before entry.
What control measures can be used for a herd with evidence of endemic infection with leptospirosis from herd screening or abortion serology?
Decision must be made whether vaccination worthwhile. If herd vaccination started - should continue annual booster for whole herd. heifers should complete vaccination course before first mating.
What is the most common source of infection of leptospirosis?
Purchase or hire of an infected animal or contact with infected animals on common grazing. Vermin or other wildlife species play no part in spreading L hardjo infection.
What is the cause of malignant catarrhal fever?
Ovine herpes virus 2.
How does MCF occur?
Relatively rare sporadic disease in the uk affecting cattle and deer. Unusual to see more than one case on a single period of time but outbreaks can occur. contact with sheep or goats seems to be necessary for transmission of the disease. Cases of MCF may occur months after contact with sheep suggesting prolonged incubation or latent infection possible. Cattle are dead end hosts and dont transmit MCF.
What are the clinical signs of MCF?
Intense scleral congestion, bilateral keratitis, depression, anorexia, pyrexia, erosive stomatitis of buccal mucosa and muzzle, profuse muco purulent oculo nasal discharge, superficial ln enlargement, nervous signs may include hyperaesthesia and tremors, diarrrhoea.
How is diagnosis of MCF made?
CNS signs are rare with any other mucosal disease - history of sheep contact and characteristic clinical signs. Characteristic pm and histopathological findings. Serological test available but may not be positive at time of clinical signs initially presenting.