Indian Journal of Animal Research

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Indian Journal of Animal Research, volume 57 issue 7 (july 2023) : 836-840

Obtaining Ejaculates through Operant Conditioning of the Golden Eagle (Aquila chrysaetos)

J.A. Herrera-Barragán1, S.S. Landa-García2, J.J. Pérez-Rivero1,*, J.M. Huitrón-Rodríguez3, M.Á. León-Galván4, A. Guzmán-Sánchez1, C.S. Reyes-Mendoza5
1Departamento de Producción Agrícola y Animal, Universidad Autónoma Metropolitana-Xochimilco. Calzada del Hueso 1100, col. Villa Quietud, Coyoacán, 04960, CDMX, México.
2Maestría en Biología de la Reproducción Animal, Universidad Autónoma Metropolitana-Iztapalapa. Av. San Rafael Atlixco 186, Leyes de Reforma, 09340 CDMX, México.
3Maestría en Ciencias Agropecuarias, Universidad Autónoma Metropolitana-Xochimilco. Calzada del Hueso 1100, col. Villa Quietud, Coyoacán, 04960, CDMX, México.
4Departamento de Biología. Universidad Autónoma Metropolitana-Iztapalapa. Av. San Rafael Atlixco 186, Leyes de Reforma, 09340 CDMX, México.
5Parque Reino Animal. Camino a Belén, Santa María, Oxtotipac, Otumba, C.P. 55908, Edo, Méx., México.
Cite article:- Herrera-Barragán J.A., Landa-García S.S., Pérez-Rivero J.J., Huitrón-Rodríguez J.M., León-Galván M.Á., Guzmán-Sánchez A., Reyes-Mendoza C.S. (2023). Obtaining Ejaculates through Operant Conditioning of the Golden Eagle (Aquila chrysaetos) . Indian Journal of Animal Research. 57(7): 836-840. doi: 10.18805/IJAR.B-1342.
Background: The golden eagle, Aquila chrysaetos is one of the 65 species of birds of prey found in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora. It has been estimated that the world population is 250 thousand specimens. The operant conditioning to obtain ejaculates of A. chrysaetos is described and to contribute to assisted reproduction protocols in captivity.

Methods: In the reproductive season, the procedure was performed twice a week on 5 adult birds, in order to obtain ejaculates.

Result: The study lasted 17 weeks, in which 160 contacts were made in total. It was possible to obtain 20 ejaculates, which were obtained from 3 birds. 4% success was achieved in obtaining ejaculates. Additionally, behaviors of clinical utility for diagnosis, care and well-being were conditioned in birds. The above should be considered in assisted reproduction programs, since, as demonstrated by the results of this study, not all the birds provide sufficient ejaculates, for which reason, the evaluation of the individuals that present the greatest advance in operant conditioning to include them in assisted reproduction programs.
Currently at least 10% of the 300 species of the falconiform order are threatened worldwide (Dogliero  et al., 2016). Mexico is a very diverse country, in which there are 1096 species of birds, 88 of them are birds of prey, among which is the golden eagle, Aquila chrysaetos considered one of the 65 species of birds of prey that are in category of risk at national level according to NOM-059-SEMARNAT-2010, being classified in appendix II of CITES (CITES, 2015). The world population of A. chrysaetos is estimated at 250 thousand individuals. The number of individuals residing in Mexico is unknown to date; however, approximately 50 nests have been documented in the wild and more than 60 specimens in captivity (CONABIO, 2011). Birds play a crucial role in food webs of ecosystem and are known as ‘bio-indicators’ a sensitive to minor environmental changes (Debnath et al., 2018).

Due to the limited knowledge of the species, breeding in captivity is far from being successful (Blanco et al., 2009; Dogliero  et al., 2016), in addition to possible consequences that can be generated by stress in captivity, such as incompatibility between couples and aggressiveness, situations that cause inability to copulate naturally or asynchronous copulations (Blanco  et al., 2009; Dogliero  et al., 2016). Therefore, efforts have been made to incorporate artificial insemination (AI) in bird conservation programs; however, problems have been found to carry it out, derived from inefficiency in the training of birds for the semen collection (Blanco  et al., 2009; Dogliero  et al., 2016). In wild animals, unlike domestic species, simple contact with humans is not sufficient for imprinting and/or training to carry out diagnostic and therapeutic procedures (McGreevy  et al., 2014; Beulah et al., 2020). Operant conditioning (OC) explains that the consequences of a behavior are what determine whether or not it will be reissued. If a behavior has positive consequences, there will be a greater probability that it will happen again and/or its frequency will increase (Huston et al., 2013). An example of the above has been described in Rhesus monkeys, where the use of OC with positive reinforcement was successfully used to reduce aggressive behaviors against other animals and personnel who handle them (Miniera  et al., 2011); it has also been used for these animals to allow clinical maneuvers and to safely obtain ejaculates from the specimens (Clay  et al., 2009; O´Brien  et al., 2009; Schapiro  et al., 2003).

Therefore, the objective of this work is to incorporate OC as a tool to facilitate the handling A. chrysaetus specimens in order to obtain ejaculates safely for the animals and the personnel that handle them.
The work was carried out in the Neotropical region of Mexico, during breeding season 2020, from January to April (Espinosa et al., 2001). Five adult males in captivity, 4 to 12 years old, were included. The birds were housed in individual enclosures, with exposure to natural events such as rain, heat, cold and winds of different intensities, as well as the presence of a female of the same species per male, which was separated from the male by a barrier according to the enclosure of each one. The diet of the birds was integrated by rabbit, mouse and chicken meat, providing a total of 109 kcal/kg (Hand et al., 2000).
Birds collections locations
Parque Reino Animal: DGVS-ZOO-P-0074-03 -MEX
Club Futbol América / Aguilario Club América: DGVS-PIMVS-CR-IN-1847-CDMX/18
Aviario DILAJESH: DGVS -CR-IN-917-MEX/06
In each location, a specific physical area was defined to carry out the conditioning management of each birds. The five birds had previous training in behaviors used for falconry, such as staying on a glove on a person’s arm and vision covering. Once this behavior was confirmed in all the birds during 17 weeks, they proceeded to carry out their conditioning to obtain ejaculates.

Tactile stimuli were performed using the dorso-ventral massage, which consisted of applying a gentle massage on the back in the head-cloaca direction, until it touched the pelvic bones, repeating it until the bird showed signs of relaxation (Fig 1), followed by a massage from the ventral area to the cloaca (Fig 2A), to finally apply light pressure, evert the cloaca (Fig 2B) and achieve ejaculation, which was collected with a graduated micro pipette (Fig 2C and D).

Fig 1: Dorsal contact showing wing relaxation.

Fig 2: Conditioning carried out to obtain ejaculates. Cloacal contact (A), Rudder lift and cloacal pressure (B) Ejaculate collection (C and D).

The conditioning sessions were carried out twice a week with a maximum of three stimuli per day per individual, without establishing schedules, so that the training was not related by the specimens to any other concurrent activity or casual event. Table 1 shows the protocol followed for the training of the specimens, establishing criteria to evaluate the progress in behavior. The conditioning of behaviors was reinforced in a positive way after each session and according to the criteria of progress, using the food that was part of their daily diet. In the case of obtaining an ejaculate, it was evaluated in a conventional way using spermatobioscopy (McGreevy et al., 2014; Villaverde-Morcillo  et al., 2015; Herrera et al., 2013). Semen was discarded if contaminated with urine or fecal material (Blanco et al., 2009).

Table 1: Progress criteria for training and obtaining Aquila chrysaetos semen.

Obtaining ejaculates
During 32 sessions in which 160 contacts were made with the specimens, a total of 480 stimuli were achieved through the dorso-ventral massage.

The progress criteria for training and obtaining semen from A. chrysaetos are shown in Table 1. On the other hand, general information on the golden eagles used is shown in Table 2.

Table 2: General information on the golden eagle (A chrysaetos) used.

Seminal indicators
The seminal parameters are shown in Table 3.

Table 3: Seminal parameters obtained by conditioning of golden eagle (Aquila chrysaetos).

Regarding age, there was no evidence of a relationship between the age of the specimens and the number of ejaculates obtained from each one. This study demonstrates that the OC procedure allows obtaining and collecting adequate ejaculates, which can be used in assisted reproduction programs in captivity. Just as those obtained in the study carried out by Villaverde-Morcillo  et al., 2015, in which the semen characteristics of a single specimen of golden eagle trained to allow semen recovery through cooperative copulation are described, in this study, azoospermic ejaculates were observed at the beginning and end of the reproductive season; similarly, a variation in ejaculate volume, concentration and sperm motility was observed, indicating the high variability of ejaculates of the species; In which rescued specimens that cannot be returned to the wild can be integrated (Aslan  et al., 2018). According to Starling (2013), the effectiveness of operant conditioning is linked to the learning capacity of each subject, the ability of the trainer to apply that type of training and the routine interaction with the subject.

With the above, the importance of this work is evident, for with the correct and efficient training the selection and evaluation of the specimens that are intended to be used as breeders is allowed, without exposing at any time the integrity of the specimens or trainers, in addition of obtaining ejaculates; behaviors of clinical interest were achieved, including techniques that can help ejaculate collection more efficiently (McGreevy et al., 2014; Callealta et al., 2019). Additionally with assisted reproduction in birds, it contributes to the conservation of many species (Sami, 2015).
According to the obtained results, the degree of progress in OC is different among different animals; a specimen can be an excellent donor from which sufficient ejaculates can be obtained, which makes it ideal within an assisted reproduction program. However, there are other specimens that may have a lower capacity and require more OC sessions to donate their genetic material and even find individuals from whom no progress is obtained; therefore, it is recommended to include the largest number of birds in the OC programs to select those with the highest progress to consider them for assisted reproduction programs.
Omar Álvarez Jiménez/ Animal trainer / Club-América
The handling of each specimen was carried out according to the official management plan authorized by the Dirección General de Vida Silvestre (DGVS) –SEMARNAT-México.

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