Effect of Progesterone Levels in Hand-Made Sponges for Estrus Synchronization on Reproductive Performance of Etawah Goats

Lalu Ahmad Zaenuri*, Lukmanhy Lukmanhy, Musanip Musanip, I Wayan Lanus Sumadiasa

Faculty of Animal Science, Mataram University, Majapahit Street No. 62 Mataram-83125, West Nusa Tenggara, Indonesia.

Received | July 25, 2025; Accepted | September 18, 2025; Published | November 07, 2025

*Correspondence | Lalu Ahmad Zaenuri, Faculty of Animal Science, Mataram University, Majapahit Street No. 62 Mataram-83125, West Nusa Tenggara, Indonesia; Email: [email protected]

Citation | Zaenuri LA, Lukmanhy L, Musanip M, Sumadiasa IWL (2025). Effect of progesterone levels in hand-made sponges for estrus synchronization on reproductive performance of Etawah goats. J. Anim. Health Prod. 13(4): 1194-1200.

DOI | https://dx.doi.org/10.17582/journal.jahp/2025/13.4.1194.1200

ISSN (Online) | 2308-2801

Copyright: 2025 by the authors. Licensee ResearchersLinks Ltd, England, UK.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

INTRODUCTION

The goat is a domesticated animal valued for its high-quality meat and milk, with global demand for goat meat. Research on goats is less extensive than on other livestock, such as cattle and poultry (Omontese, 2018). The Peranakan Etawah (PE) goat, a crossbreed of the Kacang and Etawah goats, is a dual-purpose breed that is more expensive than the Kacang goats, limiting breeder access and improvement. To maintain genetic purity, re-crossing with full-blood Etawah bucks is necessary, using natural breeding or artificial insemination.

Artificial Insemination (AI) is widely used to enhance goat genetics and productivity through liquid or frozen semen (González-Marín et al., 2021; Sharma and Sood, 2019). It allows for genetic quality testing, optimizes the use of superior males, and reduces costs. Leethongdee and Ponglowhapan (2014) highlight AI’s advantages, including improved genetic selection and the ability to store genetic material through semen cryopreservation, enabling the use of frozen-thawed semen in AI. However, the challenges include the need for trained technicians, specialized equipment, and time for estrus detection, as well as the risk of inbreeding from inaccurate semen data recording. Mathivanan (2014) and Meghwanshi (2024) recommend accurate data recording to mitigate these issues.

The success of AI relies on the estrus state of the animals. In small farms, estrus detection is straightforward, allowing for natural breeding. However, large farms face challenges with estrus detection, making AI time-consuming and costly. Estrus synchronization is therefore essential for simultaneous AI. Over the past 70 years, hormonal therapies have been developed for small ruminants (Gonzalez-Bulnes et al., 2020). Murtaza et al. (2019) found that progesterone and progestogens were effective for estrus induction,

Controlled Internal Drug Release (CIDR) is a widely used method for estrus synchronization, yielding positive results (Zaenuri, 2018). Techniques include the use of progesterone sponges (Santos, 2023; Hameed et al., 2020), GnRH and PGF2α combinations (Yendraliza et al., 2011), and progesterone combined with PGF2α (Murtaza et al., 2020). Administering 200 to 500 IU of PMSG during sponge removal is also effective (Hameed et al., 2020). Progesterone halts estrogen production, allowing livestock in the luteal phase to continue their reproductive process. After removing the progesterone sponge, all animals will enter the follicular phase and experience synchronous heat within approximately 48 h (Zaenuri, 2018).

This study seeks to identify the optimal concentration protocol for estrus synchronization and fixed-time artificial insemination (FTAI) to improve pregnancy rates in Etawah cross does. The findings will serve as a reference for effective progesterone use in synchronizing estrus and increasing pregnancy and kidding rates.

MATERIALS AND METHODS

Experimental does

Forty-five multiparous does were confirmed as non-pregnant via ultrasonography and randomly assigned to three treatment groups of 15 does each. Their body weights ranged from 42 kg to 45.6 kg, with an equal age or parity distribution within the groups. The average body condition score (BCS) was 3 (1 to 5), as assessed by Mendizabal et al. (2011). Each group received one of the following estrus synchronization protocols: A 100 mg (P410), 150 mg (P415) and 200 (P4200) in intravaginal progesterone sponge, respectively.

To ensure that the does were free of parasites, they received 0.2 ml Ipomec (PT. Romindo Primavetcom, Indonesia) subcutaneously per 10 kg of body weight and 10 g of Warmzol (PT. Medion Farma, Indonesia) orally per 100 kg of body weight. The animals acclimatized for two weeks before estrus synchronization.

Housing, feeding and drinking

The experimental animals were housed in a 1.5 × 1.5 m pen each. It received a diet of 50% Sesbania grandiflora leaves and 50% native grass, offered twice daily, totaling at least 15% of its body weight. Water was available ad libitum.

Hand-made progesterone sponge preparation

To prepare the handmade progesterone sponges (HMPS) as per Zaenuri (2018), cut a sponge to 2.75 cm in diameter and 3 cm in length. Tie it with 25-cm nylon thread using a sewing needle, piercing from the bottom to the top. Reinsert the needle from the right to the left, directing it to the top where the threads meet, and insert downward to connect the ends at the bottom. Leave 15-cm of thread, with 5 cm outside the vagina for easy removal. Sterilize the sponge in 70% alcohol for 15 min, then dry at room temperature for 24 h. Finally, inject 100, 150, and 200 mg of Medroxy Progesterone Acetate (Depo Progestin™ Harsen, Indonesia) into the sponge and refrigerate for 72 h, for the respective treatment.

Protocol for estrus synchronization and estrus detection

A handmade progesterone sponge (HMPS) was inserted into the vagina using a sterilized PVC applicator (20 cm long, ½ inch in diameter). Position the sponge at the applicator’s end with the nylon rope downward. Lubricate the tip for easier insertion, then insert it 10 to 15 cm until resistance is felt at the cervical os. Hold the sponge in place and withdraw the applicator, leaving the sponge in position. The HMPS removed by pulling the nylon rope 12 days later (Zaenuri and Rodiah, 2016). The experimental timeline is shown in Figure 1 as recommended by Zaenuri (2018), where the CIDR remains in the vagina for 10 to 14 days, consistent with the luteal phase of the natural estrus cycle.

 

Estrus was monitored using teaser castrated bucks every 4 h for about 20 min, from 12 to 72 h after HMPS withdrawal, recording the start and end times for each doe. Estrus behavior identified by the immobility reflex, as described by Martínez-Álvarez et al. (2007).

Semen preparation, insemination and pregnancy diagnosis

Semen was collected from two fertile Etawah bucks using an artificial vagina. Fresh semen must meet the following parameters: 2.5×109 sperm/mL, <80% motile sperm, and >20% abnormal sperm per ejaculate. It was diluted in a tris-egg yolk extender (Zaenuri, 2018). A single AI dose was 0.5 mL, containing 150×10^6 sperm, was administered 48 h after HMPS withdrawal (Zaenuri, 2018). AI was conducted with a duckbill speculum and an external light source, while ewes were restrained with their hindquarters elevated.

The pregnancy rate was evaluated using the non-return rate within two cycles (NRR47), with teaser bucks used twice daily from days 18 to 21 and 39 to 42. Confirmation was performed via ultrasonography (SonoScape, Co. LTD, Shenzhen, China) on day 47 post-insemination. Birth occurrences and the number of kids per birth were recorded about five months later. The pregnancy percentage was calculated as (number of NRR47 does/number of inseminated does) x 100% (Kukovics et al., 2011).

Data recorded

The recorded parameters included the following: percentages of does showing behavioral changes and restlessness (+) versus no estrus behavior (-); mucus quantity rated as 1 = low, 2 = medium, 3 = high; vulvar edema rated as 1 = pale, 2 = reddish, 3 = red; estrus onset as the time from sponge withdrawal to the first accepted mount; estrus duration as the time from the first to the last accepted mount; and the percentage of does in estrus calculated by combining the number of does indicating estrus (+) with mucus quantity and vulvar edema. NRR47 was the percentage of does not returning to estrus until 47 days post-insemination. The pregnancy rate was the number of does detected as pregnant via ultrasonography, the kidding rate was the percentage of does that kidded between 145 and 150 days of pregnancy, and the prolificacy rate was the average number of kids per group.

Statistical analysis

Statistical processing was performed using non-parametric analysis for comparison of two means and proportions, using Student’s t-criterion (Stat-Soft 1984-2000 Inc. statistical software). Differences were considered significant when P values were < 0.05 (Steel and Torrie, 1991).

RESULTS AND DISCUSSIONS

Sexual behavior

The results on sexual behavior and clinical signs of treatment are shown in Table 1, revealing significant differences (P < 0.05) in positive sexual behavior scores in P4200 (85%) compared to P410 (67%) and P415 (67). Significant difference (P < 0.05) also noted vaginal mucus score and swollen vulva in P4200 compared to P410 and P415. Table 2 indicates that the onset and duration of estrus were 32.2, 33.3, and 35.1 h for treatments P410, P415, and P420, respectively, with no significant differences (P < 0.05). The percentages of estrus also showed no significant differences (P < 0.05) among the treatments.

This study’s results were lower than those of Saleh et al. (2021), who found that about 81% of the does in the PMSG9 group exhibited estrus behavior 24 hours (n= 18) and 28 hours (n= 17) after CIDR removal. In comparison, only 69% and 61% of the does in the PMSG14 and PG14 groups, respectively, showed estrus behavior during these periods. The treatment groups began exhibiting estrus behavior as late as 44 h after PMSG injection, while those not receiving PMSG began showing estrus behavior within 48 to 52 h after CIDR removal.

Estrus signs, recognized before insemination, include behaviors like mounting, tail wagging, and nudging (Zaenuri, 2018). Salleh et al. (2014) showed that PMSG significantly increased the number of animals in estrus. Skliarov et al. (2021) stated, synthetic progesterone-impregnated sponges improve estrus during and after the breeding season.

 

Table 1: Effect of different progesterone concentrations on sexual behavior and clinical signs of estrus in Etawah crossbred goats.

Treatments	n	Sexual behavior		Vaginal mucus (score range 1-3)			Swollen vulva (Score range 1-3)
		+	-	1	2	3	1	2	3
P410	15	10 (67%)	5 (33%)	2 (13%)	3 (20%)	10 (67%)	2 (13%)	3 (20%)	10 (67%)
P415	15	10 (67%)	5 (33%)	3 (20%)	3 (20%)	9 (60%)	2 (13%)	3 (20%)	10 (67%)
P420	15	14 (85%)a	1 (10%)	0 (0%)	2 (13%)	13 (87%)a	1 (10%)	2 (10%)	12 (80%)b
Total number	45	34	11	5	8	32	5	8	32
%	100	75	25	11	17.7	71.3	11.1	17.8	71.1

 

Note: different superscripts in the same rows indicate significant differences (P < 0.05).

 

The onset, duration, and percentages of estrus showed no significant differences (P < 0.05) among the treatment groups. However, the P420 group had a longer onset (35.1 hours) than P410 (32.2 hours) and P415 (33.5 hours), likely due to its higher progesterone concentration (200 mg) compared to P410 (100 mg) and P415 (150 mg) (Table 2). Unfortunately, blood progesterone levels in this study were not analyzed. Skliarov et al. (2021) indicated that goats not showing estrus behavior often have high progesterone levels in their milk after treatment, suggesting functional corpora lutea, while low levels indicate cyclicity despite the absence of estrus behavior.

This study used liquid progesterone injected into a sponge, whereas remained in the vagina for 12 days, aligning with the luteal phase of the estrus cycle (Zaenuri, 2018). This is comparable to the CIDR, which stays in place for 10 to 14 days (Arkose et al., 2023). Yendraliza et al. (2011) reported that estrus synchronization with GnRH and PGF2α resulted in estrus onset in ewes between 37.4 and 38.4 h. Deac et al. (2024) noted that variations in estrus onset depend on the synchronization protocol, experimental design, and the breed and age of the animals.

The durations of estrus in this study were 28.4 h, 31.2 h, and 31.7 h for P410, P415, and P420, respectively (Table 2). Estrus duration may vary due to age, body condition score (BCS), parity, and nutrition. Simões et al. (2024) indicated that estrus duration reflects environmental and management factors as well as reproductive disorders. The onset rate (33.8 h) and duration (30.43 h) of estrus in this study were within the normal ranges of 36.00 ± 3.89 h (Meghwanashi, 2024), 4 to 64 h in buffalo (Arkose and Uslu, 2022), and 36.7 ± 5.1 h in progesterone-treated ewes, and 42.6 ± 5.31 h for ewes with a progesterone-impregnated intravaginal device for 7 days (Simões et al., 2024).

 

Table 2: The effect of different dosages of progesterone in hand-made sponge on estrus synchronized in Etawah does.

Observed parameters	Treatments
	P410	P415	P420	P-value
Onset of Estrus (h)	32.2	33.3	35.1	NS
Duration of Estrus (h)	28.4	31.2	31.7	NS
Percentage of Estrus (%)	70	70	80	NS

 

NS= Not Significant (p<0.05).

 

The percentages of estrus in all three treatment groups of does were not significantly different (P<0.05), although the P420 group showed a relatively higher percentage than P410 and P415 (Table 2). This may be due to higher progesterone levels, allowing all the experimental animals to enter the follicular phase. Thus, when the progesterone sponge is removed, all treated does may exhibit estrus simultaneously, leading to increased pregnancy and kidding rates (Zaenuri, 2018). Environmental factors such as feed, nutrition, light intensity, and temperature significantly influence estrus occurrence and synchronization (Kukovics et al., 2011). In addition, breed, age, feed quality and quantity, management, and season also affect estrus quality and synchronization (Salim et al., 2020; Zaenuri and Rodiah, 2016). The continuous confinement of goats in the pen may have impacted the intensity of estrus and fertility in this study.

Non-return rate, pregnancy, kidding rate and litter size

There were no significant differences among the treatment groups (P < 0.05) for NRR47, confirmed by ultrasonography on day 60 (Table 3). The non-return rate is a simple and cost-effective method to evaluate AI outcomes. If the animals do not return to estrus within two cycles, they were likely pregnant, as indicated by pregnancy rates similar to the ultrasonography results, except for one abortion in the P420 group (Table 3). This study’s results were lower than the initial non-return rate of 93.33% for Boer goat estrus synchronization with 2 mL PGF2α 72 hours before insemination using semen in coconut water with a 10% egg yolk extender, compared to 73.33% for semen in tris-aminomethane with a 10% egg yolk extender (Salim et al., 2020). The does in this study varied in parity, with higher parity linked to greater prolificacy (Zaenuri, 2018). Factors affecting AI outcomes include insemination timing after estrus synchronization, semen quality, sperm concentration, technician skill, and method (Kukovics et al., 2011). Artificial Insemination in this study was performed 48 to 50 h after progesterone sponge withdrawal, aligning with the recommendations from previous studies: 48 to 50 h (Saleh et al., 2021), and 58 to 63 h (Salim et al., 2020).

 

Table 3: Reproduction performance in does as a response of different concentrations of progesterone sponge and artificial insemination.

Parameters	Treatments			P-value
	P410	P415	P420	NS
NRR47, n (%)	8 (53)	9 (60)	9 (60)	NS
Pregnancy rate, n (%)	7 (47)	8 (53)	9 (60)	NS
Kidding rate, n (%)	7 (47)	8 (53)	8 (53)	NS
Litter size	1.3	1.63	1.5

 

Fresh liquid semen in the Tris-egg yolk extender was used in this study. The observed pregnancy rate (40-60%), as shown in Table 3, was lower than the 70-82% reported by Salim et al. (2020) but higher than the 56.7% found by Alvarado-Espino et al. (2022) for goats inseminated with liquid semen stored at 5ºC for 24 h. Sadeghi et al. (2020) recommend chilling semen for 1.5 to 4 h to reach 4-5°C for optimal AI results. Intra-cervical insemination with fresh diluted semen is commonly practiced at the farm level (Leethongdee and Ponglowhapan, 2014). Wiebke et al. (2021) also noted that this cooling process extends sperm viability for 12 to 24 h by reducing metabolism and toxic byproduct production.

Intra-cervical insemination with frozen-thawed semen has lower fertility rates than cervical insemination with fresh semen (Zaenuri, 2018). The highest fertility rates are found in does age 1.5 to 4.5 years (Zaenuri, 2018). This study’s pregnancy rate (40-60%) is lower than the 86.7% reported after natural mating with fluorogestone acetate synchronization (Martemucci and D’Alessandro, 2011) but higher than that reported in some previous studies. Menchaca et al. (2011) reported pregnancy rates of 50.4%, 42.7%, and 34.2% for intra-cervical AI using a tris-yolk semen extender stored at 5ºC for 0, 12, and 24 h, respectively. When inseminated after 12 h post-estrus detection, pregnancy rates were 37.4% and 23.4% at 48 and 54 h, respectively. Leethongdee and Ponglowhapan (2014) found a 15.79% pregnancy rate with single cervical insemination using 150 x 10^6 frozen-thawed spermatozoa, increasing to 38.70% with double insemination (p < 0.05).

There was no significant difference in pregnancy rates among goats inseminated at 48 h (46.8%, 22/47) and 60 h (46.3%, 19/41) or between 60 and 72 h (Alvarado-Espino et al., 2022). Intra-cervical insemination with fresh diluted semen is commonly used in goat artificial insemination (Leethongdee and Ponglowhapan, 2014). When performed correctly, this method achieves high fertility rates, while frozen-thawed semen results in lower fertility. The low conception rate in this study may be due to the less accurate progesterone concentrations in the hand-made sponges. For the accurate concentration of progesterone in the treatment, commercial progesterone sponges or CIDR are options (Alvarado-Espino et al., 2022; Leethongdee and Ponglowhapan, 2014). However, progesterone in hand-made sponges is much more cost-effective for small-budget budget farmers and researchers.

Kidding rate is the most accurate method for evaluating natural versus AI results. Table 3 indicates no significant differences in the pregnancy and kidding rates among the treatment groups. However, litter sizes in groups P415 and P420 were higher (1.63 and 1.5, respectively) than in P410 (1.3). Salim et al. (2020) found kidding rates of 40% and 66.66% in Boer does inseminated with semen in Tris-aminomethane with 10% egg yolk and with coconut water and 10% egg yolk, respectively. Agosau and Koluman (2018) found that; pregnancy rates were significantly higher (P < 0.05) at 93% (28/30) for AI compared to 70% (21/30) for natural mating. The litter sizes were 1.8 for natural mating and 2.1 for AI.

Successful AI depends on external factors such as timing after estrus synchronization, insemination method, inseminator skills, semen type (liquid or frozen), and sperm concentration (Kukovics et al., 2011; Zaenuri, 2018). Internal factors include the reproductive health of female goats, age, parity, reproductive tract condition, normal cycling, and nutrition (Kukovics et al., 2011). Female livestock reproductive success is measured by fertilized egg preservation, successful births, and offspring quality, whereas male success is assessed by the number of mated and fertilized ova (Deac et al., 2024).

CONCLUSION

Different progesterone concentrations in handmade sponges did not significantly impact estrus behavior, synchronization, or reproductive performance in Etawah goats. More research is needed to identify the optimal hormone levels, sperm concentrations per insemination, and timing across a larger sample.

ACKNOWLEDGMENTS

The project was funded by the Ministry of Research, Technology, and Higher Education of the Republic of Indonesia, which financed this research through the National Strategic Research Institute 2011-2025 (Contract No. 770/UN18.Li/PP/2023). The authors sincerely appreciate all the goat farmers who were involved directly or indirectly during the study.

NOVELTY STATEMENT

Progesterone is commonly used with other hormones for estrus synchronization in goats. This study introduces a novel method using only progesterone, providing practical, simple, and cost-effective, good results, and applicable especially for small farmers.

Author’s Contribution

All authors contributed to the research planning, design, implementation, data collection and analysis. Lalu Ahmad Zaenuri, the first author and corresponding author, prepared the first draft of the manuscript. This was then discussed with the author team, including revising the manuscript as requested by the journal’s editorial team, and the final version was approved by all outhors.

Generative AI and AI-assisted technology statement

All data and content in this article come from research that we have conducted. The authors declare that no Generative AI was used in the creation of this manuscript.

Conflict of interest

The authors have declared no conflict of interest.

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