Acquiring a horse who has clearly had a setback in care — with the aim of restoring him to full health — can be hazardous.

Often, it cannot easily be determined why the horse has fallen into his present state and whether those issues can be fully remedied. If a horse is found to be thin and debilitated at a veterinary pre-purchase examination (PPE), the largely external nature of this examination, taken with the often unreliable dietary and veterinary history supplied by the owner, can place the examining vet in a difficult position when advising the client as to whether or not he will recover.

Certainly, if you are thinking of buying such a horse, a PPE is highly desirable. This will include a detailed inspection of the horse’s teeth, and maybe also a blood test to investigate any debilitating illnesses that might be present.

If you do decide to take on a horse with an unknown history, or a youngster who arrives looking less than a picture of health, a good first question would be: “Is he wormy?”

Although parasites, principally redworms, are an important cause of debility in adult horses, determining whether they are responsible for failure to thrive in an individual case can be difficult. Contrary to a widely held belief, there is no correlation between the faecal worm egg count (often erroneously called a “worm count”) and the number of worms in the horse. Horses with high egg counts may be healthy, but are an important source of infection for other horses. Conversely, those with a large burden of encysted redworm larvae may have low counts or even be completely negative. Tapeworm will often also go undetected.

Horses who are persistently thin are often described as “worm damaged”. There is actually no evidence that even a severe parasitic colitis (an inflammation of the colon lining), if the horse survives it, causes any irreparable damage. With good aftercare and correct nutrition, an affected horse can make a full recovery.

If no information on the horse’s worming history is available, the likelihood of the presence of a heavy burden may have to be inferred from his background — perhaps he has come from heavily stocked premises, for example, with overgrazing and poor management.

Treatment, based on veterinary advice, may be needed. However, it must be administered with care in the winter if there is a chance that the horse is heavily infected with encysted redworm larvae. The sudden killing of these parasites might provoke an adverse reaction.

It may be prudent for the horse to receive anti-inflammatory medication at the same time as being treated with moxidectin, the wormer of choice in this situation. Although a five-day course of fenbendazole is marketed for the treatment of encysted redworms, resistance to this 40-year-old drug is now widespread — and the inflammatory response, if it does work, is greater than with moxidectin.

A possible redworm burden must be treated with care to avoid a potential adverse reaction

Back to basics

Lice are common in malnourished, debilitated horses during winter and spring, unless the horse has been clipped. Itching of the neck, chest and buttocks is a giveaway sign.

The eggs, called nits, look like hayseeds but are attached to the hair shafts. Adult lice may also be seen if the hair is carefully parted, especially if this is done immediately after a rug is removed. Topical treatment should be given on veterinary advice, as some of the lice treatments sold in tack shops and feed stores are ineffective.

Overgrown, neglected feet must be corrected by trimming. Severe overgrowth should be removed in two or more stages, each around two weeks apart. The aim is to correct any excess growth, rebalance the foot to centralise the load into the centre, reduce any misshapen areas known as flares and address hoof cracks. A poorly shod horse may require repeated sessions with a skilled farrier over an extended period before his feet regain satisfactory function.

The horse should be observed eating hay prior to purchase, as if he has any difficulty in doing so that is significant. A full dental examination is mandatory at the PPE and allows a prognosis to be given. Sharp enamel points alone do not generally cause weight loss, unless accompanied by quidding (dropping unchewed feed) or abnormal salivation. It is often thought that “a good rasping” will improve a horse’s body condition, but this is rarely the case.

Soft or cowpat-style droppings should be regarded with suspicion in a thin horse. If dietary causes can be excluded, essentially eating either rich grass or soft, wet, low-fibre haylage, there may be an underlying inflammatory bowel problem which might prove difficult to resolve.

consult with your vet about an appropriate worming programme

Building condition

Assuming that all other health issues have been dealt with, it should be possible to put weight on a malnourished horse in around four to six weeks. Plenty of good summer grass, or the best- quality hay (soft, green and leafy) or haylage, fed ad-lib, should be the cornerstone of the new diet.

Any substantial increase in hard feed levels must be implemented gradually and carefully to gain maximum nutritional benefit without causing additional problems.

In order to keep the meal size small, at least three, or preferably four, feeds should be given over a 24-hour period.

It is logical not to ride the horse during his recovery, as some of the extra calories and protein provided will be diverted to provide the “fuel” for movement rather than rebuilding his body condition.

There is sometimes a reluctance to feed a horse adequately as there is a concern that this will make him more difficult to ride — although evidence that diet truly affects a horse’s temperament under saddle consult with your vet about an appropriate worming programme is almost entirely anecdotal. If this is a consideration, increased calories and protein can be provided by feeding high-calorie, fibre-based feeds, such as oil- fortified alfalfa combined with a feed balancer.

The horse’s body condition score should gradually improve, but this can be subjective and sometimes disheartening. Monthly weighing with a weight tape will allow his progress to be monitored more objectively. If there is no significant improvement in six weeks, seek further advice from your vet. In the majority of cases, there is no reason why a thin horse cannot be restored to a healthy state provided common heath issues are addressed. However, inevitably, a few of these horses are found upon further investigation to have persistent or unmanageable illnesses — and turn out to be a bad buy.

Case study

When the gamble pays off: annie Warren’s Missy arrived from Ireland in poor condition, but appropriate care allowed the pair to enjoy a season’s hunting six months later

Annie Warren bought five- year-old mare Missy unseen from a dealer in Ireland last spring.

“I wanted a horse to produce and bring on,” says Annie. “Missy looked great in the photos and videos I saw, but when she came off the lorry I was a bit shocked. She had travelled badly and was noticeably thin and tucked up.

“I had little by way of health history to work with, so I organised a veterinary assessment,” she adds. “Her hooves were good but quite long, so I had those properly trimmed. A week later she developed a bad respiratory infection and extensive ringworm. I was quite worried about her.”

After considerable veterinary input and a whole summer on good grass, Missy was finally restored to full health.

“I wasn’t really happy with her condition until the autumn,” says Annie, who hunted her successfully all winter. “By then she had put on weight and looked much better. I was so relieved that there were no long-term problems. Missy proved to me that with the right advice and feeding, you can make a huge difference to a horse who has had a bad start.”

Ref: Horse & Hound; 8 March 2018