Estrous cycle characteristics and response to estrus synchronization in mammoth asses (Equus asinus americanus).
Abstract: Breeding records from a herd of mammoth asses (Equus asinus americanus) maintained on pasture in southeast Texas from 1990 to 1998 were reviewed. Jennies were pasture or hand mated, and estrus was either observed while the jennies were on pasture or when exposed to a jack after being penned. Eighty-one estrus periods and 43 diestrus intervals were recorded in 33 jennies over 4 seasons of the year (January-March, April-June, July-September, and October-December). Estrous cycle length and the duration of estrus were similar among seasons. Over all seasons, estrous cycle length was 23.3 +/- 2.6 d, duration of estrus was 5.9 +/- 2.1 d, and diestrus length was 17.4 +/- 2.6 d (mean +/- SD). During these same 9 yr, 58 injections of PGF2 alpha (5 mg, i.m.) were administered to 38 jennies without regard to stage of estrous cycle. Seventy-six percent (44/58) of the jennies showed signs of estrus after PGF2 alpha treatment, with an interval to estrus of 4.4 +/- 1.6 d and a duration of estrus of 5.6 +/- 1.7 d. Two estrus synchronization schemes were also assessed. Trial 1 was performed in October to November 1996, and Trial 2 was performed in February to March 1998. In Trial 1 (Group PE + PGF, n = 10), each jenny was injected intramuscularly once daily for 10 d with 150 mg progesterone and 10 mg estradiol-17 beta in sesame oil, and PGF2 alpha (10 mg) was injected intramuscularly on the last day of treatment. In Trial 2 (Group PGF-2X, n = 11), each jenny was injected intramuscularly twice, 16 d apart, with 10 mg PGF2 alpha. All Group PE + PGF jennies responded to treatment. One jenny in Group PGF-2X did not respond to either injection of PGF2 alpha, while 2 jennies responded to the first but not the second PGF2 alpha injection (8 of 11 jennies returned to estrus and ovulated after the second PGF2 alpha injection). Duration of estrus was 6.8 +/- 1.9 d for Group PE + PGF and 7.1 +/- 1.8 d for Group PGF-2X jennies. Interval to estrus and interval to ovulation following the last treatment were 9.0 +/- 0.9 d and 14.5 +/- 1.7 d, respectively, in Group PE + PGF jennies, and 4.5 +/- 0.9 d and 10.4 +/- 1.8 d, respectively, for Group PGF-2X jennies. In summary, estrous cycle characteristics of mammoth asses are similar to those reported for standard jennies, and estrus synchronization schemes used in horses are effective in mammoth asses.
Publication Date: 2000-03-29 PubMed ID: 10735123DOI: 10.1016/S0093-691X(99)00175-2Google Scholar: Lookup
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- Journal Article
Summary
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This study explores the estrous cycle of mammoth asses (Equus asinus americanus) and measures the effect of estrus synchronization. The researchers reviewed breeding records from 1990 to 1998, documented estrous cycles and patterns, and conducted trials using two estrus synchronization schemes.
The Study
- The paper is based on the analysis of breeding records from a herd of mammoth asses on a pasture in southeast Texas over 8 years.
- The researchers documented 81 estrous periods and 43 diestrus intervals in 33 jennies across four seasons.
- These data helped to provide an overview of the estrous cycle length, duration of estrus, and length of diestrus, observing little variation among seasons.
Estrous Cycle Patterns
- The average estrous cycle length across all seasons was found to be around 23.3 days.
- The duration of estrus averaged 5.9 days, and diestrus length was about 17.4 days.
- Estrus was either observed while the jennies were grazing or when brought into a pen and exposed to a jack.
- These data indicate that the estrous cycle characteristics of mammoth asses are consistent and similar across seasons.
Estrus Synchronization Trials
- The researchers performed two estrus synchronization trials. In the first trial, each jenny was injected daily for ten days with progesterone and estradiol-17 beta, and PGF2 alpha was injected on the last day of treatment.
- In the second trial, each jenny was injected twice, 16 days apart, with PGF2 alpha.
- The success of the treatments was also evaluated, and it was observed that all jennies in the first trial group responded to the treatment, whereas in the second trial, one jenny did not respond and two only responded to the first injection.
Conclusions
- The study concludes that the estrous cycle characteristics of mammoth asses are similar to those reported for standard jennies.
- It was also found that estrus synchronization schemes used in horses are effective in mammoth asses, suggesting potential strategies for controlled breeding in these species.
Cite This Article
APA
Blanchard TL, Taylor TS, Love CL.
(2000).
Estrous cycle characteristics and response to estrus synchronization in mammoth asses (Equus asinus americanus).
Theriogenology, 52(5), 827-834.
https://doi.org/10.1016/S0093-691X(99)00175-2 Publication
Researcher Affiliations
- Texas Veterinary Medical Center, Texas A&M University, College Station 77843-4475, USA.
MeSH Terms
- Animals
- Breeding
- Dinoprost / pharmacology
- Equidae / physiology
- Estrus / drug effects
- Estrus / physiology
- Female
- Male
- Seasons
- Texas
Citations
This article has been cited 7 times.- Segabinazzi LGTM, Gilbert RO, Ambrosia RL, Bergfelt DR, Samper JC, Peterson EW, French HM. Structural and Functional Dynamics of the Ovary and Uterus during the Estrous Cycle in Donkeys in the Eastern Caribbean.. Animals (Basel) 2022 Dec 24;13(1).
- Bottrel M, Ortiz I, Hidalgo M, Díaz-Jiménez M, Pereira B, Consuegra C, Yousef MS, Dorado J. Hormonal Management for the Induction of Luteolysis and Ovulation in Andalusian Jennies: Effect on Reproductive Performance, Embryo Quality and Recovery Rate.. Animals (Basel) 2022 Jan 8;12(2).
- Dorado J, Bottrel M, Ortiz I, Díaz-Jiménez M, Pereira B, Consuegra C, Carrasco JJ, Gómez-Arrones V, Domingo A, Hidalgo M. Factors Affecting Embryo Recovery Rate, Quality, and Diameter in Andalusian Donkey Jennies.. Animals (Basel) 2020 Oct 26;10(11).
- Abdoon AS, Abdel-Rahman HA, Shawki SM, Kandil OM, Fathalla SI. Influence of follicle size, methods of retrieval on oocytes yield and morphology in Egyptian Jennies ovaries with special reference to maturation rate in vitro.. Vet Res Commun 2014 Dec;38(4):287-95.
- Kebede H, Lemma A, Negussie H. Ultrasonographic studies on ovarian dynamics and associated estrus manifestations of jennies under controlled management, Ethiopia.. Trop Anim Health Prod 2012 Dec;44(8):1965-70.
- Derar RI, Hussein HA. Ovarian Follicular Dynamics during the Estrous Cycle in Jennies in Upper Egypt.. Vet Med Int 2011;2011:860518.
- Lemma A, Schwartz HJ, Bekana M. Application of ultrasonography in the study of the reproductive system of tropical jennies (Equus asinus).. Trop Anim Health Prod 2006 May;38(4):267-74.
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