Bovine Reproduction. Группа авторов
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environmental microorganisms and normal flora, Parsonson et al. described a technique to obtain vesicular gland secretions for microbiologic examination [10]. After clipping preputial hair, the penis is extended by transrectal massage of the urethralis muscle. The glans penis is restrained by grasping it manually with sterile gauze sponges and wearing sterile gloves. After washing and disinfecting the end of the penis, the urethra is irrigated with sterile saline utilizing a sterile teat cannula. A 25‐ to 30‐cm sterile Silastic tube is passed up the urethra to a point leaving 2.5–5 cm protruding from the penis. The vesicular glands are then massaged and the secretions are collected into a sterile container.
Several treatment modalities for vesicular adenitis have been utilized. These include multiple systemic antimicrobials given at several different dosages and frequencies. Intraglandular antibiotics and intraglandular chemical ablation have shown some success. Surgical removal of chronically infected glands has been described.
Many systemic, parenteral antibiotics have been used in the past to attempt treatment of vesicular adenitis. Since spontaneous recovery commonly occurs in younger bulls, evaluation of treatment methods is complicated [4]. Earlier antimicrobials utilized include penicillin, oxytetracycline, chloramphenicol (no longer legal), sulfamethazine, florfenicol, and cetiofur [2]. These medications all produced poor treatment success rates, even though the bacterial isolates from the vesicular glands are usually sensitive to most antibiotics [2, 11]. Success was improved when increased dosages of these agents was used. Unfortunately, even at twice the recommended dose, these antibiotics often do not reach inhibitory concentrations in vesicular gland tissue [2]. Antibiotics that are highly lipid soluble and low protein binding possess a pH higher than vesicular gland fluid along with a favorable pKa, and should be chosen [4, 12]. Due to the varying clinical signs of vesicular adenitis, establishing whether treatment is successful can be difficult. Treatment can be considered successful when the ejaculate contains less than one neutrophil per five high‐powered fields (1000×) [4].
More recently, tilmicosin and tulathromycin have shown efficacy for treatment of vesicular adenitis [13]. The author has treated multiple older bulls successfully using subcutaneous tulathromycin. There is evidence these antimicrobials accumulate in macrophages and neutrophils, which carry the antibiotics into sites of infection to be released slowly [14, 15]. Recovery rates were higher for bulls treated with tulathromycin than tilmicosin in all age groups; thus tulathromycin at this time appears to be the drug of choice [2].
Intraglandular injection of antimicrobials or chemical ablation agents is another option for treatment of refractory vesicular adenitis. Multiple antimicrobial agents have been utilized in this technique, all with varying results. Success has been achieved in some cases utilizing a single intraglandular injection of ceftiofur or penicillin. In one study, bulls were treated with intraglandular penicillin or intraglandular ceftiofur. Bulls that did not recover were treated with whichever antibiotic was not used initially. Approximately half of the bulls receiving the second treatment responded. Bulls that did not recover after intraglandular treatment with ceftiofur and penicillin recovered after three treatments of tilmicosin [13].
Chemical ablation of chronically infected vesicular glands utilizing 4% formalin has been described [16]. The success of parenteral tulathromycin as an initial treatment has substantially reduced the usage of chemical ablation in the author's practice. Resolution of vesicular adenitis after intraglandular formalin ablation approached 100% when utilized by the author. The procedure requires the bull to be restrained in a chute with epidural anesthesia. After clipping and prepping an area lateral to the anus, a 14‐gauge needle is placed through the skin directly caudal to the affected vesicular gland (Figure 14.3). The affected gland is grasped transrectally to stabilize it for injection and a 30‐cm, 18‐gauge needle is introduced through the 14‐gauge needle (Figure 14.4). This needle is advanced pararectally to achieve penetration of the affected vesicular gland. When sure the needle is within the gland, inject 10–15 ml of saline to ensure proper needle placement. Gland enlargement verifies proper needle placement. At this point, inject 4% formalin to a volume where the gland is enlarged with a smooth surface (Figure 14.5). In the author's experience, this will be approximately 50 ml. After injection, the bull should be treated with flunixin meglumine for three days, as most bulls show signs of abdominal discomfort. The proper authorities should be consulted regarding current legal use and withdrawal time prior to the extra label use of formalin for chemical ablation.
Figure 14.3 Placement of a 14‐gauge needle through the skin.
Source: Courtesy Josh Thompson.
Figure 14.4 Passing a 30‐cm, 18‐gauge needle through the 14‐gauge needle into the vesicular gland.
Source: Courtesy Josh Thompson.
Figure 14.5 After removing the stylus from the needle, the proper solution is injected into the vesicular gland.
Source: Courtesy Josh Thompson.
Surgical removal of the vesicular glands may be considered in bulls that do not spontaneously recover or do not respond to antimicrobial treatment or ablation. A subrectal approach has been described that provides better visualization of the vesicular glands and improved postsurgical fertility than traditional pararectal approaches. None of the described techniques for surgical gland removal has provided uniform success in returning a bull to function [1].
Any specific plan for prevention of vesicular adenitis is limited by the lack of a definitive pathogenesis. Proper herd health and husbandry may play an important role in reducing the prevalence of vesicular adenitis. Proper vaccination and deworming help support the overall health and general disease resistance of bulls. Proper nutrition and bunk management to reduce the incidence of rumen acidosis may reduce the possibility of hematogenous bacteria reaching the vesicular gland. Monitoring the genetic lines of bulls with vesicular adenitis may reveal a genetic basis for the disease. Although early detection, with or without medical intervention, has not shown a significant reduction in the incidence of clinical vesicular adenitis [17], herds with a high prevalence of adenitis may benefit from early transrectal palpation and treatment [2].
References
1 1 Wolfe, D. (1999). Accessory sex glands. In: Large Animal Urogenital Surgery (eds. D.M. Wolfe and H.D. Moll), 321–325. Baltimore, MD: Williams and Wilkins.
2 2 Barth, A. (2015). Vesicular adenitis. In: Bovine Reproduction (ed. R.M. Hopper), 109–112. Ames, IA: Wiley.
3 3 Cavalieri, J. and Van Camp, S. (1997). Bovine seminal vesiculitis: a review and update. Vet. Clin. North Am. Food Anim. Pract. 13: 233–241.
4 4 Koziol, J. and Armstrong, C. (2018). Transrectal examination. In: Society for Theriogenology Manual for Breeding Soundness Examination of Bulls (eds. J.H. Koziol and C.L. Armstrong), 43–45. Montgomery, AL: Society for Theriogenology.
5 5 Grotelueshen, D., Morimer, R., and Ellis, R. (1994). Vesicular adenitis syndrome in beef bulls. J. Am. Vet. Med. Assoc. 205: 874–877.
6 6 Blom, E. (1979). Studies on seminal vesiculitis