Author:
Ayanie Tilaye Demissie,Wassie Alebachew Tilahun,Kebede Ebisa Merga,Mekonnen Tefera Yilma,Geleto Tamrat Degefa,Biru Alemayehu Lemma
Abstract
Abstract
Background
Difference in breed, nutrition status and climate in which animals are managed result in differences in response to reproductive hormones. Fertility rate to artificial insemination is very low in Ethiopian Boran and Boran*Holstein crosses. This partly maybe due to adopting estrus and/or ovulation synchronization developed for temperate taurine cattle. Experimental study was conducted to evaluate ovarian response to combinations of Gonadotrophin-Realizing Hormone agonist (gonadorelin) and ProstaglandinF2α (PGF2α) with or without progesterone (Controlled Internal Drug Release/CIDR), and conception rate to timed AI. Postpartum native Ethiopian Boran (n = 60) and Boran*Holstein cross (n = 66) cows were randomly assigned to four treatment groups as Ovsynch (gonadorelin on day of start, PGF2α seven days later, 2nd gonadorelin at 48 h of PGF2α and insemination at 19 h of the 2nd gonadorelin); CIDR + Ovsynch (same as Ovsynch but CIDR device was inserted into vagina for 7 days); Cosynch (same as Ovsynch but insemination was made at the 2nd gonadorelin) and CIDR + Cosynch (same as Cosynch but CIDR was inserted for 7 days).
Result
There was no difference (P > 0.05) in ovulation rate to day 9 gonadorelin (88.33% in Boran; 78.79% in Boran*Holstein) and interval from day 9 gonadorelin to ovulation (36.5 ± 1.13 h in Boran and 36.057 ± 1.11 h in Boran*Holstein). Dominant follicle immediate to ovulation (14.95 ± 0.19 mm Vs 19.12 ± 0.49 mm) and corpus luteum size (16.31 ± 0.33 mm Vs 20.28 ± 0.43 mm ) respectively were smaller (P < 0.05) in Boran than Boran*Holstein. Plasma progesterone concentration at PGF2α was higher (P < 0.05) in Boran (11.91 ± 0.74ng/mL) than Boran*Holstein (6.13 ± 0.27ng/mL) but luteolysis rate was lower (P < 0.05) in Boran (87.9%) than Boran-Holstein (96.9%). Cows with CIDR had higher conception rate than cows without CIDR (72.00% Vs 39.02% in Boran*Holstein and 74.07%, Vs 51.52% in Boran respectively). Insemination at 19 h of gonadorelin administration resulted in higher conception rate (78.6% for Boran; 71.43% for Boran*Holstein) than insemination at gonadorelin (69.29% for Boran; 66.67% for Boran*Holstein).
Conclusion
Boran cows have smaller preovulatory follicles, smaller corpus luteum, large amount of progesterone and lower rate of luteolysis to PGF2α compared to Boran*Holstein. The CL of Boran cattle seems les reactive to PGF2α than Boran*Holstein CL. CIDR significantly improved conception rate in Boran and Boran*Holstein cows.
Funder
Addis Ababa University Research and Technology Transfer
Publisher
Springer Science and Business Media LLC
Subject
General Veterinary,General Medicine
Reference30 articles.
1. Mekonnen H, Birgitta M, Jan P. BORAN: Indigenous African cattle with potential (Cited 2010) http://www.landbou.com/jou-mening/boereblogs/boran-indigenous-african-cattle-with-potential
2. Pursley JR, Mee MO, Wiltbank MC. Synchronization of ovulation in dairy cows using PGF2α and GnRH. Theriogenology.1995;44:915–23.https://doi.org/10.1016/0093-691X(95)00279-H
3. Lemaster JW, Yelich JV, Kempfer JR, Fullenwider JK, Barnett CL, Fanning MD, Selph JF. Effectiveness of GnRH plus prostaglandin F2a for estrus synchronization in cattle of Bos indicus breeding. J Anim Sci. 2001;79:309–16. https://doi.org/10.2527/2001.792309x.
4. Kulumsa Agricultural Research Center (KARC). Annual Report of KARC 2008, Asella, Ethiopia. p. 6
5. Ginther OJ, Knopf L, Kastelic JP. Temporal associations among ovarian events in cattle during oestrous cycles with two or three follicular waves. J Reprod Fertil. 1989;87:223–30. https://doi.org/10.1530/jrf.0.0870223.