Self-sucking is a common problem in dairy animals, resulting in milk loss as well as udder damage, mastitis, and breeding animal culling [18].
In the present study, despite several trials of isolation and application of bull rings with spikes, the problem persisted and there was a great fear of the spread of this anomalous behavior by imitation from the neighboring cows. This agrees with Abou-El-Ella [7] who stated that due to the failure of all traditional control methods such as isolation and application of bull rings with spikes, the surgical interventions are the last trial to resolve the problem and the long-term benefits from the surgical procedures are more satisfactory than the conservative methods.
The previous glossectomy techniques for treatment of this problem relied on the surgical excision of varying thicknesses of tongue tissues to disrupt the tongue's contour and prevent it from curling, making milk suction difficult. The procedures of these techniques are time- consuming, may necessitate general anesthesia and result in tongue tissue damage, which can lead to bleeding and sepsis. Furthermore, determining the precise size and thickness of the tongue tissue to be excised is a major challenge with these techniques [12].
El-Sherif and Seddek et al. [12, 13] performed less-invasive surgical methods by applying silk stitches to the tissues of the tongue to make the tongue's dorsal surface convex to prevent this abnormal behavior. These techniques had a low success rate in the long term because the amount of tongue tissue involved in the stitches was less than the minimum amount required to make a change in the tongue contour, so the animals could theoretically continue sucking after surgery [8–10]. Furthermore, prolonged use of non-absorbable multifilament braided suture material with a high capillary ascension in the moist environment of the oral cavity promotes bacterial infections, which could lead to glossitis or the formation of a tongue abscess [19, 20].
In the current study, the piercing implant created mechanical disruption of the affected animals' ability to curl their tongues in a U-shape, rendering these animals unable to cup their tongues and suck milk from their own teats. Here, the tongue has the ability to perform its function efficiently after the operation and all animals were allowed to drink and eat freely after the operation compared with other surgical techniques. The food was offered after 12 hours in the sublingual-mucosal-resection technique and after 24 hours in the partial glossectomy technique. This may be attributed to the post-operative pain associated with these techniques, which dissuades the animals from feeding [21].
In this study, tongue piercings are performed with a sheep stainless trocar with cannula and the implant consists of a barbell with two screws; one is fixed and the other is removable. In humans, barbells are the most common implant placed in the tongue after it has been pierced with a hollow needle. It is made up of a stem that varies in length and has a ball-shaped tip on each end [22].
In humans, tongue implants are made from a variety of different materials such as surgical stainless steel, silver and gold, as well as synthetic materials such as teflon, nylon, and plastic. Recently, implants made of natural materials such as stone, wood, horn, ivory and bone have been developed [23]. In the present study the implant was made of plastic material, which is characterized by its superior bio-compatibility [24].
In this study, the tongue is pierced dorsoventrally, and the implant is inserted in the midline of the tongue, anterior to the frenulum linguae, from the dorsal surface to the ventral surface. Peticolas et al. [22]described two kinds of tongue piercing. The dorsoventral is the most common and harmless technique. The dorsolateral piercing in which, the implant is placed along the lateral edges of the tongue. Because the lateral tongue is highly vascularized and innervated, this is not a risk-free procedure.
The piercing procedures in the present study were performed under sedation and local infiltration analgesia and this agrees with Farah and Harmon, [25] who said that piercing in people is not a painful procedure and carried out without anesthetic and mainly performed by nonmedical self-trained individuals or dental personnel with varying degrees of proficiency.
Because human oral microflora is diverse and abundant, it's important to keep the pierced area clean, and antiseptic mouthwash must be used three to four times per day until the entire healing process is completed and if a patient complains of pain, oedema, and an inflammatory reaction from tongue piercing, the implant should be removed, local debridement performed, and antiseptic, anti-inflammatory, and antimicrobial treatment administered to hasten healing and resolve the problem [25].
Jornet et al. [26] performed tongue piercing in dogs and clinically found that none of the implants caused significant edema or hemorrhage, as well as none of the complications associated with human piercing. Pathologically, the piercing canal had been completely re-epithelialized at the expense of the healthy epithelium at the surgical wound's edge.
In the present study only slight swelling around the piercing site of the tongue was recorded in all animals on the first three days after surgery and no other complications have also been reported. This may be attributed to the large number of salivary glands in ruminants that contribute to the production of large amounts of saliva, which can reach 100 L per day in adult cattle [10]. Saliva has been shown to hasten the wound healing process for a variety of reasons. Saliva produces moist environment, which improves the viability and activity of inflammatory cells, which are essential for wound healing; saliva has plenty of tissue factor, which helps blood clot faster. Furthermore, saliva includes a variety of peptides and proteins which provide protection against microbial pathogens by inhibiting bacterial adhesion and neutralizing microbial toxins [27, 28].