Being on top of ailments during lambing helps raise flock health
Several surveys have shown that 90% of lamb losses and 75% of ewe deaths occur at or around lambing. Correct diagnosis and treatment of disease at lambing is, therefore, essential to guarantee a prosperous lamb crop and healthy ewes for the following year.
Most common conditions seen at this time can be put down to poor nutrition and low colostrum intake. When you get these two things right you, your sheep and your vet will be a lot happier.
Watery Mouth
This condition is a result of the action of bacterial endotoxins produced in lambs that have a delayed or inadequate colostrum intake. It causes a wet muzzle, an abomasum full of saliva and gas and often the meconium has not been expelled.
Research has shown that lambs receiving colostrum (200ml/kg) within 30 minutes of birth do not succumb to watery mouth, so it is essential all lambs have adequate colostrum. Only cases observed early will respond to treatment, ideally oral and injectable antibiotics and a small dose of anti-inflammatory.
Oral rehydration is also essential, with small and often doses given by stomach tube being the ideal. Lambs should be kept warm and milk can be reintroduced once the abdominal distension is reduced and a suck reflex is present. Those that have already collapsed are highly likely to die as a result of endotoxaemia.
Hypothermia
Similarly, inadequate colostrum intake will frequently cause lambs to become hypothermic commonly triplets, small lambs, sick lambs or those being raised by inexperienced ewes are most likely to succumb – although weather can extend this group to include otherwise healthy animals.
Treatment in part is determined by how cold the animal is, but also how old it is.
The worst case scenario is a lamb more than five hours old with a temperature less than 37C which cannot hold its head up this will require an intra-peritoneal dose of dextrose (10ml/kg of 20% dextrose), before the lamb is warmed and then fed by stomach tube.
It can then be returned to its dam, although close monitoring at this stage is still essential to detect any relapse. Any other animal with a temperature less than 39C should be stomach tubed, warmed and then given a second feed before being returned to its dam.
Joint Ill
True lameness in neonatal lambs is not common, most cases resulting from trauma at birth. In contrast, incoordination resulting from abnormal development of the nervous system (swayback, border disease and other causes) is relatively common.
However, the most common cause of lameness in lambs is joint ill. This usually affects several joints in one or more limbs, with or without obvious joint distension or navel infection. A plethora of bacteria is capable of causing joint ill, but they are clinically indistinguishable. When cases do not respond to broad-spectrum antibiotic and anti-inflammatory treatment, vet attention should be sort.
In these cases swabs can be taken for culture and antibiotic sensitivity and the joint drained and flushed. In the face of an outbreak, treatment of every newborn lamb with antibiotic may be necessary until hygiene is improved, but this should only be used in severe situations and not as an alternative to the following control strategies.
Prevention centres on hygiene at lambing, castration and tailing. Provision of clean bedding in both the lambing and individual pens is essential, alongside disinfection between animals. Navel dressing should be checked at 24 hours and when still damp re-applied. When a spray gun is used it is easy to leave areas uncovered, whereas dip jars need to be changed regularly to prevent contamination.
Entropion – In-turned eyelid
It is essential to realise entropion is a genetic hereditary disease passed down from parents to lambs. It is always worth making a permanent record of those affected, so they are not retained for the breeding flock, since once they have recovered there is no evidence of the condition having existed. If occurring in large numbers it is worth investigating which ram is carrying the trait – by the use of raddles etc – and consider replacing that animal.
This condition is best checked for at birth, as at this time often the only correction needed is to pull the lower eyelid out and into the normal position. When this is not effective, or in older animals, the signs of the condition are more obvious with swelling of the eye, tears flowing down the face of the animal and in chronic cases changes in the eye itself.
At this stage the eyelid should be pulled into the correct position and then held in place by injecting antibiotic into the eyelid (1-1.5ml procaine penicillin using a 20 or 21G needle. Please consult your vet if you have not done this before – it is an easy technique which can be quickly taught) or by the use of metal clips. Don’t forget to make a note of the ear tag number.
Prolapses
Prolapses can be a significant problem on some farms and yet a rare occurrence on others and the reasons behind this are not always obvious. Some regard a prolapse as merely a nuisance that adds to an already lengthy job list pre-lambing.
However, although foetal loss is not inevitable, ewes that have prolapsed pre-lambing will have a far higher than normal foetal death rate. Even when live lambs are delivered, there is a high likelihood the same animal will re-prolapse in years to come therefore, it is normal to cull those affected.
Factors implicated in predisposing ewes to pre-lambing prolapses are numerous, including large pelvis breeds, feeding bulky feeds once daily, being over fat in late pregnancy, short docking of the tail, chronic cough and low blood calcium levels.
Treatment of mild vaginal prolapses can easily be done with harnesses or intra-vaginal devices. However, cases where the ewe is showing severe straining, swelling and damage to the prolapsed tissue or post-lambing uterine prolapses should receive vet treatment – including epidural injection to prevent straining, antibiotic, anti-inflammatory and calcium therapy and possibly suturing of the vulva to prevent recurrence.
Pregnancy Toxaemia
Pregnancy toxaemia can be a common condition among heavily pregnant ewes, particularly those carrying twins. Early signs include onset of blindness which, other than the obvious signs of the animal colliding with gates and fences, can cause them to become segregated from the rest of the flock.
As the condition worsens the signs become more obvious with the development of teeth grinding, salivation, muscle tremors and constipation before ataxia, weakness and eventual recumbency results. This will usually occur three to four days after the first signs are evident and at this stage abortion is a real possibility.
Even when the pregnancy is not affected, these animals commonly develop dystocia at lambing, retained foetal membranes and small amounts of poor quality colostrum and milk.
Treatment centres on raising blood glucose levels either by delivery of twice daily oral propylene glycol or glucose/electrolyte mixtures, or intravenous glucose injections. Concurrent hypocalcaemia is a common finding, so subcutaneous calcium is often beneficial, alongside provision of adequate shelter, good quality food and encouragement to eat.
Prevention relies on frequent condition scoring and alteration of feed patterns in light of this information.
The aim is to reach a condition score of 3.5 for lowland breeds or 3 for hill breeds at tupping by having a raising plane of nutrition over the pre-tupping and first month of pregnancy period, reducing to a level plane over the second and third month of pregnancy to prohibit any fat deposition.
During the fourth and fifth months of pregnancy foetuses grow by 80% of their birth weight, so fortnightly condition scoring and grouping according to results is essential to prevent weight loss and attain optimum lamb birth weights.
*XLVets is group of farm animal committed vet practices who work together, alongside commercial research and manufacturing companies. They aim to share best practice on advice and disease prevention initiatives.
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