26 January 1996

Plan for a healthy flock

In 1995 Dr Agnes Winter, of Liverpool Universitys Veterinary Field Sation, received the George Headley Award, the UKs highest honour for contributions to the sheep industry. Here, she advises Robert Davies and Jeremy Hunt on how to keep both ewe and lamb in fine fettle before, during and after lambing

LIVERPOOL University-based vet Dr Agnes Winter reckons that flock scanning-to-weaning lamb losses can be cut to under 10% simply by shepherds putting current knowledge into practice.

Birth is a high risk event for both ewe and lamb, admits Dr Winter. But even so, the national average 4% to 6% ewe and 15% lamb mortality rates can be reduced significantly.

"The majority of major causes of death are down to factors which have been known for years, and for which good preventative strategies are available or – if prevention falls down – appropriate treatment can be implemented," she says.

Mortality rates vary across flocks and Dr Winter suggests that few farmers have a true picture of the figure within their own flocks because they do not keep sufficiently detailed records. And the financial impact can be very serious.

In her experience, the most successful flocks are those where advanced planning is good, and veterinary input not limited to lambing-related "fire brigade work".

Health programme

"Utopia for the sheep veterinarian may not be attainable, but is drawing up and implementing planned flock health programmes as a matter of course for each flock too much to ask? I hope not," questions Dr Winter.

"Todays flockmasters have many advantages not enjoyed by their forebears. More is known about altering a ewes body condition through correct feeding – a decision now often based on scanning results. The control of metabolic diseases is better understood, and there is access to vaccines against many diseases."

Many flocks now lamb indoors, and ATVs make it easier to move materials and sheep outside. Though no one claims to be able to reduce mortality to zero, flock losses are often far too high, says Dr Winter. Most ewes die as a result of:

lMetabolic diseases such as pregnancy toxaemia.

lInadequate or inappropriate vaccination.

lProlapses of various types.

lThe consequences of difficult or assisted lambings.

lMastitis.

Though a proper flock health management plan can minimise the incidence of controllable diseases, there are no easy answers for the prevention of prolapses.

"The best that can be done with current knowledge is to give early and humane treatment," she says. "In my opinion it is crucial to correct a cervical/vaginal prolapse as early as possible, when an external support such as a truss will suffice.

Onset of straining

"Neglect leads to the onset of straining sooner or later, making successful replacement much more difficult. Proper veterinary attention is desirable for advanced cases, with suturing – when necessary – under epidural anaesthesia to relieve straining for 24 hours or more by use of appropriate drugs."

Prompt veterinary intervention will successfully replace a uterine prolapse, but Dr Winter warns that a sudden catastrophic intestinal prolapse is inevitably fatal. Then the only concern is to humanely kill the ewe as soon as possible.

When dealing with difficult lambings she is adamant premature intervention is as dangerous as delaying too long. The person responsible for the flock must have the skill to assess quickly whether the case is suitable for assistance by the shepherd, or if veterinary help is required.

Training important

"Good practical training is very important. I am sad about what has happened to training through the Agricultural Training Board, with which I, and many other veterinary surgeons, once worked closely. Unskilled assistance can result at best in a sick ewe, because of bruising or infection, or, at worst, a dead ewe," says Dr Winter.

Acute mastitis, often with gangrene, is usually seen in full lactation and little can be done to prevent it. Acute infection at lambing is extremely uncommon. Most mastitis found at lambing is usually a reflection of undetected post-weaning mastitis.

"Of course the weather is the one factor which cannot be controlled. But proper advanced planning can go a long way to making the difference between a successful lambing and failure.

"There are no startling new messages, merely the application of already well tested management tools," she says.

An impending cervical prolapse. There are no easy answers to the prevention of prolapse in ewes, so the best that can be done with current knowledge is to see that they get early and humane treatment.

Dr Agnes Winter says few farmers have a true picture of mortality in their flocks, because they do not keep sufficiently detailed records.

The weather is one factor which cannot be controlled by the shepherd at any time of the year. But proper planning can go a long way to making the difference between a successful or depressing lambing.