Preventive medicine for miniature pet pigs

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Miniature pet pigs have an average life expectancy of 15 to 18 years but can live as long as 20 to 25 years. Boars reach puberty at 3 months and gilts at 3.5 to 4 months. Their estrous cycle averages 21 days (17-25 days).

Vaccination

The vaccination of pet pigs is a controversial topic. Whereas there are standardized vaccination protocols for food-producing pig populations, no such protocols exist for pet pigs. Different authors recommend different vaccines, and recommendations depend on the region where the patient lives (exposure risk), the number of pigs in a household, exposure to wildlife, and whether it is kept indoors or allowed outdoors. Deciding what to recommend to clients can therefore be challenging.

In addition to the lack of standardized vaccination protocols, there is also the use of off-label vaccines, such as those for rabies. Rabies is extremely rare in pigs in the United States but has been reported in miniature pigs kept as pets.

If you chose to vaccinate pig patients against rabies, use inactivated vaccines. These vaccines have not been scientifically evaluated in pet pigs, and their efficacy cannot be guaranteed. State or local public health authorities should always be contacted for guidance in case exposure has occurred. For more information about endemic areas and risk of exposure, refer to the CDC website.

Anthelmintic treatment

As part of a preventive medicine plan, it is important to perform regular fecal tests (every 6 to 12 months) and administer anthelmintic treatments as needed.

Hoof and tooth care

Pigs have a diphyodont, heterodont, and brachydont dentition. Their decidual dental formula is 2(i 3/3, c 1/1, p 3/3), and their permanent dental formula is 2(I 3/3, C 1/1, P 4/4, M 3/3). However, it is important to note that male canine teeth (tusks) are aradicular, hypsodont, and elodont. Because they will grow throughout the animal’s life, they may become very long and sharp, potentially damaging the adjacent soft tissue and even inflicting injury to owners or other pets. Tusk removal is not recommended; instead, tusk trimming can be performed as needed, usually at 6- to 12-month intervals.

The procedure requires sedation or anesthesia. The cutting blade of a rotary tool or a high-speed dental tool can be used. Always trim perpendicular to tusk growth, not parallel with the gingival margin. The use of a tongue depressor behind the tusk to be trimmed is recommended to protect surrounding soft-tissue structures. To avoid the pulp cavity, it is crucial that the tusks be trimmed 3 to 4 cm above the gingival margin. The use of a rotary tool’s sanding stone is also recommended to round out the edges.¹ Neither cutters nor other crushers should be used because they can lead to fractures.² Potential complications include damage to the adjacent soft tissue, abnormal growth pattern of the teeth, root abscess after short trims, and pain.³ A complete oral examination can be performed at the same time, with any dental problems addressed as needed.

Overgrown hooves also need to be trimmed. The frequency with which this is done will depend on the surface on which the pig is kept, and sedation will likely be necessary. A good strategy is to advise owners to train pets to allow their feet to be manipulated because some well-trained pigs will accept conscious hoof trimming.

Trimming, including of the dewclaw, can be performed with small hoof trimmers or rotary tools, and afterward they can be made smooth and shaped with a sanding disc.¹ The hoof vasculature can extend into the hoof wall of extremely overgrown hooves, so it’s important to be familiar with the procedure and stop before reaching the vasculature.¹

Elective spays

Although uterine smooth muscle neoplasms are uncommon in most domestic mammals, they are highly prevalent in potbellied pigs. Because these pigs are rarely or never bred and typically have a lifespan of 10 to 15 years, continuous long-term ovarian cycling may predispose the animals to estrogen-responsive neoplasms.

A retrospective study evaluating spontaneously occurring uterine tumors in potbellied pigs found uterine neoplasia in 17 out of 106 (16%) females. Uterine leiomyoma was diagnosed in 11 cases, leiomyosarcoma in 1, and undifferentiated sarcoma in 1.⁴

In another study, the uteri of 32 miniature pet pigs that underwent ovariohysterectomy (OVH) at 4 months to 19 years were submitted for gross and histologic evaluation. Fourteen pigs (43.7%) aged 5 to 19 years had smooth muscle tumors in the uterus or broad ligament. Neoplastic cells had strong expressions of estrogen and progesterone receptors.⁵ A second retrospective study showed that 34 out of 298 (11.4%) potbellied pigs presented with uterine neoplasia, with pigs aged at least 6 years more likely to present with uterine lesions.⁶

A retrospective study conducted on 108 animals of the Suidae and Tayassuidae families kept in a zoo, including Vietnamese potbellied pigs and domestic cross pigs, found that 32 (30%) had leiomyoma, 4 (4%) had leiomyosarcoma, and 13 (12%) had endometrial carcinoma.⁷ The Vietnamese pot-bellied pig was among 3 species in the study with the greatest diversity of uterine lesions and the highest prevalence of reproductive tract lesions.⁷

In all studies, leiomyoma and leiomyosarcoma were the most common uterine neoplasia. Additional studies are necessary to elucidate the role of estrogen and progesterone in the development of uterine lesions in miniature pet pigs.

Early spaying should be recommended to prevent these tumors and other lesions in female miniature pigs. There are no studies evaluating or comparing the long-term benefits or consequences of ovariectomy (OVE) versus OVH in these animals. In canines, however, it has been shown that there is no increased risk for uterine pathology in bitches spayed by OVE versus OVH.⁸ Because cystic endometrial hyperplasia, pyometra, and benign tumors are all hormone-dependent, their development can be prevented by OVE and OVH.

A retrospective study evaluating OVE by electrothermal bipolar vessel sealing and OVH by hand-tied ligatures in pet pigs found OVE to be the superior technique.⁹ Compared to the OVH group, the pigs undergoing OVE had reduced morbidity, with rapid resumption of normal appetite and activity levels. Furthermore, complications like substantial hemorrhage were encountered only in the OVH group. The sealing device in the OVE group was an invaluable tool for controlling hemorrhage, especially given the tortuous nature of the female porcine reproductive system. Reduced anesthetic and surgical time, shorter incision length, and decreased tissue handling leading to decreased postoperative morbidity are significant benefits of OVE.

Currently, there are insufficient data to determine significant long-term benefits or consequences of OVE in pigs. Because studies show that uterine lesions occur only in older female pet pigs,^4,5 and extrapolating from canine studies, OVE may be a safe alternative to OVH in young female pet pigs. However, OVH should be considered in older females, and the organ should be submitted forhistopathologic evaluation.

Potential zoonotic diseases

Pet pigs can carry many pathologic agents, and some have zoonotic potential. They include rabies, tuberculosis, ectoparasites, balantidiasis, giardiasis, Erysipelothrix sp., influenza, Streptococcus group D, Ascaris suum, leptospirosis, and brucellosis.

Reportable diseases

Any swine reportable disease and/or condition must also be reported if occurring in a pet pig. Consult the code of regulations of your state food and agriculture department for more information about reportable diseases and conditions. Additional information can be found at USDA website.

Prohibited drugs

Despite being kept as pets, pigs are still considered food-producing animals. Consequently, when prescribing medications, care must be taken to avoid drugs that are prohibited in such animals. Some prohibited drugs include chloramphenicol, clenbuterol, diethylstilbestrol (DES), dimetridazole, ipronidazole and other nitroimidazoles, furazolidone, nitrofurazone, fluoroquinolones, glycopeptides, and cephalosporins (except cephapirin). For detailed current information, consult the FDA and FARAD websites.

References

1. Tynes VV. Potbellied pig husbandry and nutrition. Vet Clin North Am Exot Anim Pract. 1999;2(1):193-208. doi:10.1016/s1094-9194(17)30147-0
2. Becker HN. Surgical procedures in miniature pet pigs. In: Reeves DE, ed. Care and Management of Miniature Pet Pigs: Guidelines for the Veterinary Practitioner. Veterinary Practice Pub. Co; 1993:67-76.
3. Asseo L. Tusk trims in miniature pigs. LafeberVet. August 4, 2020. Accessed May 10, 2022. https://lafeber.com/vet/tusk-trims-in-miniature-pigs/
4. Mozzachio K, Linder K, Dixon D. Uterine smooth muscle tumors in potbellied pigs (Sus scrofa) resemble human fibroids: a potential animal model. Toxicol Pathol. 2004;32(4):402-407. doi:10.1080/01926230490440880
5. Ilha MRS, Newman SJ, van Amstel S, et al. Uterine lesions in 32 female miniature pet pigs. Vet Pathol. 2010;47(6):1071-1075. doi:10.1177/0300985810382522
6. Cypher E, Videla R, Pierce R, et al. Clinical prevalence and associated intraoperative surgical complications of reproductive tract lesions in pot-bellied pigs undergoing ovariohysterectomy: 298 cases (2006-2016). Vet Rec. 2017;181(25):685. doi:10.1136/vr.104294
7. Goblet CC, Moresco A, Garner MM, et al. Retrospective characterization of reproductive tract lesions in relation to age, parity, and contraception in captive suidae and tayassuidae. Theriogenology. 2019;127:137-144. doi:10.1016/j.theriogenology.2019.01.012
8. DeTora M, McCarthy RJ. Ovariohysterectomy versus ovariectomy for elective sterilization of female dogs and cats: is removal of the uterus necessary?. J Am Vet Med Assoc. 2011;239(11):1409-1412. doi:10.2460/javma.239.11.1409
9. Biedrzycki A, Brounts SH. A less invasive technique for spaying pet pigs. Vet Surg. 2013;42(3):346-352. doi:10.1111/j.1532-950X.2012.01084.x

Suggested reading

• Birhane MG, Cleaton JM, Monroe BP, et al. Rabies surveillance in the United States during 2015. J Am Vet Med Assoc. 2017;250(10):1117-1130. doi:10.2460/javma.250.10.1117. Published correction appears in J Am Vet Med Assoc. 2017 Jul 15;251(2):146
• DuVernoy TS, Mitchell KC, Myers RA, et al. The first laboratory-confirmed rabid pig in Maryland, 2003. Zoonoses Public Health. 2008;55(8-10):431-435. doi:10.1111/j.1863-2378.2008.01159.x
• Goblet CC, Moresco A, Garner MM, et al. Retrospective characterization of reproductive tract lesions in relation to age, parity, and contraception in captive suidae and tayassuidae. Theriogenology. 2019;127:137-144. doi:10.1016/j.theriogenology.2019.01.012
• Proença LM. Two-portal access laparoscopic ovariectomy using ligasure atlas in exotic companion mammals. Vet Clin North Am Exot Anim Pract. 2015;18(3):587-596. doi:10.1016/j.cvex.2015.04.010
• Siepker CL, Dalton MF, McHale BJ, et al. Neuropathology and diagnostic features of rabies in a litter of piglets, with a brief review of the literature. J Vet Diagn Invest. 2020;32(1):166-168. doi:10.1177/1040638719898687
• Smith MA, Rao S, Rawlinson JE. Dental Pathology of the Domestic Pig (Sus scrofa domesticus). J Vet Dent. 2020;37(4):192-200. doi:10.1177/0898756421989097
• Tynes VV. Preventive health care for pet potbellied pigs. Vet Clin North Am Exot Anim Pract. 1999;2(2):495-510. doi:10.1016/s1094-9194(17)30134-2