Breeding Soundness Examination of the Male Llama and Alpaca

CHAPTER 116 Breeding Soundness Examination of the Male Llama and Alpaca



Breeding soundness examination (BSE) is common in several livestock species and is an excellent tool that can be used to discard males that do not fit selection criteria. In llamas and alpacas, this procedure is still under development; nonetheless, there is tangible evidence that semen evaluation may be done without much elaboration or the use of sophisticated instrumentation. This section does not deal with different traits that are used to select a sire, commonly known among llama and alpaca breeders as a “padre.” Other phenotypic criteria are beyond the scope of this section and the reader is counseled to look for further literature. Rather, this section is devoted completely to the examination of the external genitalia and their physiology, including semen evaluation and assessing circulating concentrations of testosterone. Some general criteria for identification are also considered because most BSEs will be used for future sires.




EXAMINATION OF THE EXTERNAL GENITALIA13


Testicles are a set of paired organs within the scrotum located in the perineal area of the animal. They should be ovoid in shape and resilient to digital palpation. The scrotum is relatively small, nonpendulous, and protrudes from the body outline in a position rather similar to that seen in boars and dogs. The testicles should move freely within the scrotum. Any attachment to the scrotum may signify a previous or ongoing insult to them. The longitudinal and transverse axes of the testicles may be measured using calipers. The testicles increase in size with age (Table 116-1), represent 0.02% of the animal’s body, and mature relatively slowly. Ultrasonography of the testicles may be done with the animal in a standing position or in lateral recumbency. The echo texture of the testicle is hypoechogenic with a clear echogenic line in the middle indicating the presence of the mediastinum.



The epididymis may also be palpated, and head, body, and tail portions can easily be distinguished. In llamas and alpacas, the head of the epididymis is bigger than the tail, in contrast to rams and bulls in which the tail is markedly bigger than the head.


The penis has a sigmoid flexure just cranial to the scrotum, and the tip of the prepuce is directed caudally in the nonaroused state. Thus, the stream of urine is directed backward. However, during copulation and with the aroused penis, the prepuce is directed cranially. The penis may also be inspected when the animal is sedated and in lateral recumbency. For this purpose, the sigmoid flexure may be straightened by manual manipulation and the penis may be pushed toward the preputial orifice while the other hand retracts the prepuce. A second person is needed to grasp the penis with a gauze sponge and exteriorize it to check for anatomic abnormalities. In young animals, the prepuce is attached to the penis and this natural attachment disappears with time, driven by the rise in circulating testosterone at 21 to 24 months of age. The glans penis is totally free from any attachment by 3 years of age. The process of detachment begins with the distal tip of the glans.


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Sep 3, 2016 | Posted by in SUGERY, ORTHOPEDICS & ANESTHESIA | Comments Off on Breeding Soundness Examination of the Male Llama and Alpaca

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