Revista Cienﬁca, FCV-LUZ / Vol. XXXV Recibido: 19/05/2025 Aceptado:18/08/2025 Publicado: 16/09/2025 hps://doi.org/10.52973/rcfcv-e35650 UNIVERSIDAD DEL ZULIA Serbiluz Sistema de Servicios Bibliotecarios y de Información Biblioteca Digital Repositorio Académico 1 of 5 Revista Cienﬁca, FCV-LUZ / Vol. XXXV hps://doi.org/10.52973/rcfcv-e35703 UNIVERSIDAD DEL ZULIA Serbiluz Sistema de Servicios Bibliotecarios y de Información Biblioteca Digital Repositorio Académico Inducing ferle estrus in hair goats outside the breeding season using just the female-to-female eﬀect Inducción del estro férl en cabras de pelo fuera de la temporada reproducva ulizando únicamente el efecto hembra-hembra *Mehmet Ferit Özmen , Ümüt Cirit ¹* Dicle University Faculty of Veterinary Medicine, Department of Reproducon and Arﬁcial Inseminaon, Diyarbakır, Türkiye ² Çukurova University Faculty of Ceyhan Veterinary Medicine, Department of Reproduction and Artificial Insemination, Adana, Türkiye * Corresponding authors: ferit-ozmen@hotmail.com ABSTRACT This study aimed to invesgate the impact of the female- to-female eﬀect on the ferlity traits of does outside the breeding season. In the control group (n= 16 does, 3 bucks), progestogen-containing vaginal sponges were inserted into the does for 11 days, followed by the administraon of 500 IU of eCG upon sponge removal. Mangs were completed within 36 h aﬅer sponge removal. The mated does in the control group were immediately introduced to the female eﬀect group. The does in the female eﬀect group (n= 16 does, 3 bucks) did not undergo any medical procedures. Ultrasound examinaons for pregnancy were conducted 30 to 35 days aﬅer mang and births were monitored to determine the number of oﬀspring. The control group had a higher estrus rate compared to the female eﬀect group P<0.005). The pregnancy, kidding, and aboron rates in the control and female eﬀect groups were similar (P>0.05). Goats in the female-inﬂuence group tended to have a higher mulple birth rate (P=0.059) and numerically higher ferlity and lier size compared to the control group, but the diﬀerences were not stascally signiﬁcant (P>0.05). Considering these data, it is concluded that using the female- inﬂuence group can induce ferle estrus in goats outside the breeding season, but further studies using larger numbers of goats are needed to compare this method with hormonal methods. Key words: Estrus; female-to-female eﬀect; goat; pregnancy RESUMEN Este estudio tuvo como objevo invesgar el impacto del efecto hembra-hembra en la ferlidad de las cabras fuera de la época reproducva. En el grupo control (n = 16 hembras, 3 machos), se insertaron esponjas vaginales con progestágeno en las hembras durante 11 días, seguidas de la administración de 500 UI de eCG tras la extracción de la esponja. Los apareamientos se completaron dentro de las 36 h posteriores a la extracción de la esponja. Las hembras apareadas del grupo control fueron introducidas inmediatamente al grupo de efecto hembra. Las hembras del grupo de efecto hembra (n = 16 hembras, 3 machos) no se someeron a ningún procedimiento médico. Se realizaron ecograas para determinar la gestación entre 30 y 35 días después del apareamiento y se monitorizaron los nacimientos para determinar el número de crías. El grupo control presentó una mayor tasa de celo en comparación con el grupo de efecto hembra (p < 0,005). Las tasas de preñez, parto y aborto en los grupos control y efecto hembra fueron similares (P > 0,05). Las cabras del grupo efecto hembra tendieron a tener una mayor tasa de partos múlples en comparación con las del grupo control (P = 0,059) y presentaron una fecundidad y un tamaño de camada numéricamente superiores; sin embargo, las diferencias no fueron estadíscamente signiﬁcavas (P > 0,05). Se concluyó que el estro férl puede inducirse en cabras de pelo fuera de la época reproducva mediante el efecto hembra-hembra. Palabras clave: Cabra; estro; efecto hembra-hembra; preñez

Estrus inducon by female inﬂuence / Özmen and Cirit UNIVERSIDAD DEL ZULIA Serbiluz Sistema de Servicios Bibliotecarios y de Información Biblioteca Digital Repositorio Académico INTRODUCTION Alongside the increasing populaon and food demand, the rising input costs in livestock enterprises necessitate an increase in producvity per animal. The fact that goats enter anestrus during certain mes of the year leads to economic losses. Estrus synchronizaon methods are used to prevent these losses and to plan reproducon. These methods, whether hormonal or non- hormonal, can be used together or separately. The hormones used in estrous synchronizaon are estrogen, progesterone, GnRH, melatonin, eCG and prostaglandin [1], 2 ,3, 4 ,5]. Although there are many hormonal methods, those based on progesterone and eCG are successfully and widely used throughout the year [6]. Non-hormonal methods that can be widely used in the ﬁeld include supplementary feeding protocols (ﬂushing), the male eﬀect, and the adjustment of light exposure duraon [7]. Due to reasons such as the demand for organic farming and the aversion to the use of drugs/hormones in animal producon, along with the ﬁnancial burden of drug and hormone costs on breeders, non-hormonal methods are gaining increasing importance [7]. Social factors are likely important for both iniang and synchronizing breeding acvies [8]. Sexual biosmulaon is deﬁned as reproducve smulaon provided by one animal to another of the same species [9 , 10] . In sheep (Ovis aries) and goats (Capra hircus), the sudden introducon of sexually acve males into a ﬂock of anestrous females can iniate reproducve acvity in the females [11 , 12] . This is referred to as the male (whien) eﬀect and is commonly used in the ﬁeld. It has been reported that the presence of estrous females can smulate ovulaon in anestrous ewes or does within the ﬂock [13 , 14 , 15] .This phenomenon is referred to as the “female-to-female eﬀect,” since it is facilitated by signals emied by the female [16 , 17 , 18]. The impact of estrous females on male sexual traits is well recognized in small ruminants [19 , 20]. In addion, the ﬁrst evidence suggesng that the female-to-female eﬀect can smulate ovulaon in anestrous does was reported by Walkden-Brown et al. [13] and this was subsequently conﬁrmed by various studies in the following years [11]. Despite this evidence, there has been a lack of research for many years on smulang reproducon in anestrous does through the female- to-female eﬀect. Since the 2000s, the few studies conducted on this subject have either examined the female-to-female eﬀect in conjuncon with male inﬂuence and/or hormone use, or used only one female in estrus [21 , 22 , 23]. Exposure of rams and bucks to estrous females outside the breeding season smulates them to become sexually acve [24]. It has been reported that this interacon causes a sudden increase in LH and testosterone secreon in rams and bucks, and this results in a rapid shiﬅ in behavior that smulates ovulaon in females and enhances the likelihood of successful mang [18]. Similarly, it has been demonstrated that ovulaons can be induced in anestrous does through the female-to-female eﬀect [13 , 14]. Walkden-Brown et al. [13] reported that ovulaon was detected in 66.7% of anestrous does exposed to estrous females. However, it has been suggested that unless the female is in breeding condion and recepve, ovulaon is not important for breeding ming or synchrony [8]. In goats, it was observed that when the ﬁrst ovulaon coincided with estrus, it reﬂected a heightened state of reproducve readiness [13] . Therefore, it is important to determine whether the social smulaon of the females induces reproducve condions (estrus) or merely causes a temporary physiological change (ovulaon) [8]. However, in the few studies conducted for this purpose, along with the female-to-female eﬀect, factors such as the male eﬀect and/or hormone usage were examined together [21 , 22 , 23]. The inﬂuence of the female-to-female eﬀect on the ferlity traits of anestrous goats has remained uncertain. The aim of the present study was to examine the eﬀects of the female- to-female inﬂuence on the ferlity traits of does outside the breeding season, without the involvement of the male eﬀect or hormone use. MATERİALS AND METHODS Ethical approval The study received approval from the Ethics Commiee of Dicle University Health Sciences Educaon and Research Centre (2023-568849) Study area and material The study was conducted outside the breeding season, at the end of April, in a commercial enterprise located at 37°55′01″ N latude, 40°16′46″ E longitude, and at an altude of 660 m in Diyarbakır province, Turkey. The study involved a total of 32 female hair goats, aged between 2 and 4 years weighing 40-45 kg (superscale, yıldrım tartı, Turkey) and 6 bucks. The genital organs of all goats were examined via ultrasound to conﬁrm the absence of pregnancy or estrus. The animals were randomly divided into 2 groups, each consisng of 16 does and 3 bucks, and placed in two separate semi intensive shelters located 2 km apart. To prevent the male eﬀect, bucks were also present among the does before and during the study, with no treatment applied to them. In addion to grazing on separate pastures during the day, the animals were supplemented with 200 g of lenl straw (Lens culinaris) and 300 g of barley (Hordeum vulgare) in the evenings. In the control group (n: 16 does, 3 bucks), progestogen- containing vaginal sponges (Esponjavet, Hipra, Spain) were inserted into the does for 11 days (d), and 500 IU of Pregnant Mare Serum Gonadotropin (eCG) (Ovıser,Hipra,Spain) was administered upon sponge removal. Goats that allowed bucks to approach and sniﬀ their external genitalia were considered to be in estrus. Aﬅer sponge removal, females in estrus were mated using hand mang. Mangs were completed within 36 hours of sponge removal. All females in the control group were transferred to the female eﬀect group immediately aﬅer mang and mixed with them. Thus, 16 goats in estrus were included in the female eﬀect group. Females in the female eﬀect group (n: 16 females, 3 males) received no medical treatment. Females in the female eﬀect group were exposed to the “female-female eﬀect” and observed for 7 days, and those in estrus were mated using hand mang. In both groups, pregnancy examinaons were performed with ultrasound (Esaote Aquila, Italy) 30–35 days aﬅer mang, and births were monitored to determine the number of oﬀspring. 2 of 5

Revista Cienﬁca, FCV-LUZ / Vol. XXXV UNIVERSIDAD DEL ZULIA Serbiluz Sistema de Servicios Bibliotecarios y de Información Biblioteca Digital Repositorio Académico Stascal analyses Proporonal data were analyzed by the chi-square test and numerical data were analyzed by Mann-Whitney U test. Stascal analyses were performed using SPSS 10.0 for Windows (SPSS Inc., Chicago, IL, USA). The results are presented as mean ± SEM. Diﬀerences were considered signiﬁcant at P < 0.05, while a tendency was noted for values of 0.05 ≤ P < 0.1. RESULTS AND DISCUSSION The results of the study was presented in TABLE I. The control group, which underwent estrus synchronizaon, had a higher estrus rate compared to the female eﬀect group (100 vs. 56.3%, P<0.005; TABLE I). The pregnancy, kidding, and aboron rates of the control and female eﬀect groups were found to be similar (P>0.05). The does in the female eﬀect group tended to have a higher mulple births rate compared to those in the control group (85.7 and 40.0%; P=0.059) and had numerically higher fecundity (1.44±0.29 and 0.94±0.23; P>0.05) and lier size (1.86±0.14 and 1.50±0.22; P>0.05); however, the diﬀerences were not stascally signiﬁcant. Although there was no stascal diﬀerence between our results, the 100% pregnancy rate and the 85.7% mulple pregnancy rate obtained in the female eﬀect group indicate that the method applied resulted in sasfactory pregnancy and lamb birth in goats. TABLE I Comparison of ferlity traits between the control and female eﬀect groups in hair goats outside the breeding season Groups Parameters Control Female eﬀect P value Estrus rate (%) 100 (16/16) 56.3 (9/16) =0.003 Pregnancy rate 1 (%) 81.3 (13/16) 100 (9/9) NS Kidding rate 2 (%) 62.5 (10/16) 77.8 (7/9) NS Aboron rate 3 (%) 23.1 (3/13) 22.2 (2/9) NS Mulple births rate 4 (%) 40.0 (4/10) 85.7 (6/7) =0.059 Fecundity 5 (n) 0.94±0.23 (15/16) 1.44±0.29 (13/9) NS Lier size 6 (n) 1.50±0.22 (15/10) 1.86±0.14 (13/7) NS 1: Number of pregnant does /all does mated; 2: Number of does kidding/all does mated; 3: Number of does aborted / number of does pregnant; 4: Number of does with mulple kids / number of does kidding; 5: Number of kids born/ number of does mated; 6: Number of kids born/ number of does kidding; NS: not signiﬁcant. Sanago-Miramontes et al. [21] observed that exposing anestrous does to estrogen-treated females (in numbers of 10% and 20% of the anestrous populaon) during male eﬀect exposure smulated their estrus acvity (90 and 93%, respecvely). Researchers found pregnancy rates of 45 and 48% in the 10 and 20% groups, respecvely. Similarly, Sanago- Miramontes et al. [22] reported a signiﬁcant increase in estrus rates of anestrous does introduced to estrogen-treated females compared to the control group of does (11 and 45%; P<0.05). Studies of Sanago-Miramontes et al. [22] revealed that ferle estrus can be smulated in does during the anestrus period using the female-to-female eﬀect in conjuncon with the male eﬀect. Rodríguez-Marnez et al. [23] removed the males prior to the experiment and treated the anestrous does in the eCG group (n=30) with intramuscular eCG, Prostaglandin F2α (PGF 2 α), and a single dose of progesterone (P 4 ), while the does in the P 4 group (n=39) were exposed to the females in the eCG group aﬅer receiving a single dose of P 4 injecon. Immediately aﬅer the hormone treatments, all doe groups were introduced to sexually inacve males. Estrus (97 vs. 95%), pregnancy (83 vs. 87%) and kidding rates (63 vs. %64) were found to be similar between the does treated with eCG and the anestrous does exposed to females treated with eCG (P>0.05). However, the does in the eCG group had a signiﬁcantly higher lier size than those in the P 4 group (1.9 vs. 1.6). Although similar in design to the study, the study by Rodríguez-Marnez et al. [23] includes both the male eﬀect and a single dose of P 4 applicaon. In the study, the does subjected to estrus synchronizaon exhibited a higher estrus response compared to those exposed to estrous females (100 vs. 56.3%; P<0.05), which is a result that could be expected. In the study by Rodríguez-Marnez et al. [23] the high estrus rate recorded in the P 4 group of does was parally aributed to the male eﬀect. It was suggested that the high estrus response observed in the study may be due to the immediate response of the bucks to the presence of estrous does. The most notable ﬁndings of the study were that goats exposed to the female-to- female eﬀect tended to have a higher mulple births rate (85.7 vs. 40.0%; P= 0.059) compared to those in the synchronizaon group, as well as numerically higher fecundity (1.44 vs. 0.94; P> 0.05) and lier size (1.86 vs. 1.50; P> 0.05). Another notable ﬁnding was that all the does exposed to the female-to-female eﬀect and that mated achieved pregnancy. These data clearly indicate that ferle estrus can be smulated in goats outside the breeding season using only the female-to-female eﬀect. No similar study was found in the current study. Hogan et al. [8] examined the eﬀects of including only one female goat in groups of Saanen females in estrus and noted that none of the females exhibited estrus or ovulaon. However, as the researchers noted, this may have been due to the use of only one female goat in estrus. In our study, 16 goats idenﬁed as estrus were included with 16 non-estrus goats, and estrus, mang, and pregnancy were achieved through female inﬂuence. This demonstrates that a large number of female goats in estrus are required for mang and pregnancy in goats using the female inﬂuence method. The intensity of smulaon, determined by the number of males and their libido, was reported to be an important element in triggering ovulaon in ewes [25]. When 3 of 5

Estrus inducon by female inﬂuence / Özmen and Cirit UNIVERSIDAD DEL ZULIA Serbiluz Sistema de Servicios Bibliotecarios y de Información Biblioteca Digital Repositorio Académico evaluang the studies conducted, it has been understood that the female eﬀect has two signiﬁcant posive impacts on anestrous does. The ﬁrst is its direct eﬀect, which can iniate ferle estrus in anestrous does, while the second is an indirect eﬀect that may arise from making males acve and more producve. This indicates that the female eﬀect can be more widely ulized under ﬁeld condions in goats to enhance producvity outside the breeding season and to reduce synchronizaon costs. CONCLUSIONS It was concluded from the study that ferle estrus can be induced in hair goats outside the breeding season through the female-to-female eﬀect, without the involvement of the male eﬀect or the use of hormones, nevertheless, to conﬁrm these results, further studies involving a larger number of goats are needed. Conﬂict of interest The authors declare that they have no conﬂict of interest. BIBLIOGRAPHICS REFERENCES [1] Öztürk N, Tölü C. Eﬀect of melatonin treatment on reproducve hormones and sexual behaviors in sheep. J. Tekirdag Agric. Fac. [Internet]. 2025; 22(1):221-232. doı: hps://doi.org/p45f [2] Gözer A, Sarıbay MK, Bahan O, Doğruer G, Parlaktaş M. The eﬀect of me of ecg and pgf2α administraon on ferlity parameters in akkaraman yearlings treated by mpa in non-breeding season. J. Bahri Dagdas Anim. Res. [Internet]. 2024 [cited 12 Jan. 2025]; 12(2):96-102. Available in: hps://goo.su/s6ZX [3] Arya D, Goswami R, Sharma M. Estrous synchronizaon in cale, sheep and goat. Muldiscip. Rev. [Internet]. 2023; 6(1):e20230001. doı: hps://doi.org/p45g [4] Kuru M, Kuru BB. The eﬀect of estrus synchronizaon on pregnancy rate in Abaza goats during the breeding season. 5th Internaonal Food, Agriculture and Veterinary Sciences Congress; 2023 March 17-19; Kars, Türkiye: Springer; 2023. 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Revista Cienﬁca, FCV-LUZ / Vol. XXXV UNIVERSIDAD DEL ZULIA Serbiluz Sistema de Servicios Bibliotecarios y de Información Biblioteca Digital Repositorio Académico Rev. Chapingo Ser. Cienc. For. Ambiente. [Internet]. 2011; 17:77-85. doı:hps://doi.org/fx6tbx [22] Sanago-Miramontes MA, Luna-Orozco JR, Meza-Herrera CA, Rivas-Muñoz R, Carrillo E, Véliz-Deras FG, Mellado M. The eﬀect of ﬂushing and smulus of estrogenized does on reproducve performance of anovulatory- range goats. Trop. Anim. Health Prod. [Internet]. 2011; 43:1595-1600. doı: hps://doi.org/fmf6d7 [23] Rodríguez-Marnez R, Ángel-García O, Guillén-Muñoz JM, Robles-Trillo PA, Sanago-Miramontes MA, Meza- Herrera CA, Mellado M, Véliz FG. Estrus inducon in anestrous mixed-breed goats using the “female-to- female eﬀect”. Trop. Anim. Health Prod. [Internet]. 2013; 45:911-915. doı: hps://doi.org/p45n [24] Ungerfeld R, Forsberg M, Rubianes E. Overview of the response of anoestrous ewes to the ram eﬀect. Reprod. Fert. Develop. [Internet]. 2004; 16(4):479-490. doı: hps://doi.org/dzs48j [25] Signoret JP, Fulkerson WJ, Lindsay DR. Eﬀecveness of testosterone treated wethers and ewes as teasers. Appl. Anita Ethol. [Internet]. 1982; 9(1):37-45. doı: hps://doi. org/mrwp 5 of 5