One of my favorite emerging farmers recently made an enquiry about balls that he found in the “belly” of two of his sheep after slaughter. The animals appeared healthy and in good body condition and he was amazed that the animals had swallowed such big round objects. I asked him to cut the balls open and see if he could find anything, because it could be plant balls or hairballs. The answer that came back was “How did hair end up in balls in the bellies of my sheep? And how do you prevent, cure/remove those having it and what will happen if not cured?”
After a few chuckles from me, I asked Mr. Farmer to slow down with the questions and I asked him an important question of whether he ever observed any of his sheep eating each other’s hair. Of course, his answer was in the affirmative and he confirmed that he noticed that especially the younger lambs tend to pluck and consume the hair from the back and abdomen of other animals. And some of the sheep have patches on their bodies without any hair left behind. But he didn’t think much of it as he attributed the hair loss to mites or lice and he had given them treatment for that already.
The phenomenon of hairballs found in the bellies of sheep is most likely a typical consequence of zinc deficiency in the herd of sheep, especially if sheep are eating each other’s hair. The main reason why hairballs are associated with zinc deficiency in sheep/goats is because zinc is mostly required for production of keratin (a protein that helps to form the horny tissues of the body such as hooves, horns and hair). That’s why animals with this deficiency tend to consume hair.
Another attributing factor to hairballs in animals’ digestive tract is due to their behaviour of grooming. This is more common in animals such as cats and rabbits that tend to excessive plucking of hair when grooming. But this phenomenon is not common in small ruminants (sheep and goats).
The hairballs are called by a fancy name “trichobezoar” and can be differentiated from plant balls (phytobezoars) that occurs when animals consume high amount of fibrous plants such as cotton and flowers of certain plants, especially when the veld has been overgrazed and taken over by less desirable plants. The fibrous parts of the plant mat together like wool to form the plant balls which harden like stones.
On the other hand, hairballs are softer and have a thin leathery outer shell with inner layers of wool/hair matted tightly together. The more the animal plucks hair, the more the wool becomes attached to the ball, increasing its size. You might even remove 5 or even up to 10 hairballs from one sheep rumen and they vary in size of an average of 5cm in diameter.
Usually, one or two small hairballs (or plant balls) won’t affect the animal physiologically, but if there are several of them or if the size is considerably large, then the digestive system function is impaired and the animal loose appetite and start losing weight. Since the farmers won’t have a clue about the hairballs in the rumen of the affected animals, they tend to attribute the symptoms to other problems such as worms, teeth problems et cetera, and they treat the animals with various remedies before they succumb. Some heavily affected animals might become bloated and eventually die.
For treatment, there is no remedy that will dissolve or break the hairballs. Thus, it is important to differentiate hairballs from plant balls in order to adjust the management regime. For example, if plant balls are noticed, the best preventative measure could be good grazing and veld management such as to avoid animals eating undesirable fibrous plants such as bushman’s grass, plants with flowers or seeds of grass.
If the hairballs are associated with plucking of wool due to zinc deficiency, the condition is usually easily treatable provided that the symptoms are recognized. The most noticeable sign most of our farmers will easily recognize is big-patched hair loss (alopecia) all over the body. The skin might also become dry, scaly and thick and may even become encrusted. The remaining hair becomes dull, thinner, disheveled, and loose and can easily be pulled from the animal. Other signs are abnormal hoof growth, stiff joints and lameness. There will be unusual excessive salivation and the animal will be depressed and look ill.
Sometimes people mistake the resulting hair loss to mite bites, especially when the young animals’ eating hair from the others go unnoticed. To differentiate the two situations, with hair loss due to mite bites (such as sheep scab), the animals will be itching and rubbing themselves against objects whereas they won’t when their hair’s eaten by others.
In rams, bulls and other males used for breeding purposes, an interesting consequence of zinc deficiency is the negative effect on reproductive capability since zinc is also essential for sperm production. You might find reduced interest in mating as well as abnormally small testicles. The rams sometimes have very low sperm counts on examination or these ‘little guys’ fail to swim very well to reach and fertilize the eggs of the females for conception.
For supplementation of zinc in goats and sheep, an injection of multi-minerals such as Multimin® or an oral dose of Embamin® that has an added zinc combination would be sufficient. For sheep and goats, Multimin® can be injected at least twice a year. I know this medicine is not very affordable but I’m sure those farmers who do this will attest to the changes in their stock condition a couple of days after the supplementation.
Another management strategy to prevent hairballs in sheep/goats is dietary control. Most of our farmers are not knowledgeable enough to formulate their own feeding ratio with appropriate levels of minerals and vitamins included. Achieving this is a complex task best left to a trained animal nutritionist.
Surgical removal of hairballs in affected animal’s rumen is not common and is only attempted by seasoned veterinarians, especially in high value animals. Thus, the best way of handling sheep and goats with hair balls is dietary management and supplementation in case of suspected zinc deficiency.
Dr. Baby Kaurivi-Katunahange “The Village Vet”
MVet, BVSc, BSc, Lecturing Veterinarian