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Papers by Tamrat Degefa

Tropical Animal Health and Production

International Journal of Livestock Production, 2021

The study was conducted from December 2019 to May 2020 to evaluate the efficiency of local convec... more The study was conducted from December 2019 to May 2020 to evaluate the efficiency of local convectional semen and imported sexed semen on in vivo produced bovine embryo quality in Boran and HB cross breed donor cows in Bishoftu, Ethiopia. In this study, it was hypothesized that the breed of donor cows and types of semen can influence the quality of in vivo produced embryo as well as the number of transferable embryos. Randomized experimental design was employed, and a total of 20 donor cows (10 Boran and 10H*B cross) were superovulated and flushed excluding non-responsive donor cows. Donor cows were randomly assigned to two groups: Group-1- five donors inseminated with sexed semen and group-2- five other cows inseminated with convectional semen from each breed. The results of study showed that the embryo recovery rate was 68% in H*B crossbreds and 53% in Boran donor cows. A total of 121 embryos were produced of which, 60 were transferable embryos (36 from H*B crossbreds and 24 from ...

African Journal of Biotechnology, 2016

Boran is an endangered breed of cattle indigenous to Ethiopia and the relatively poor understandi... more Boran is an endangered breed of cattle indigenous to Ethiopia and the relatively poor understanding of its reproductive physiology has impeded efforts to maximize reproductive performance of the breed. This study characterized ovarian follicular dynamics in 9 purebred Boran and 8 Boran×Holstein (B×H) crossbred cows. Ovaries of all 17 cows were examined once per day for 61 consecutive days (encompassing three periods of estrus) using transrectal ultrasonography. The mean (±standard error of mean) inter-ovulatory interval (IOI) was similar (P>0.05) in Boran (19.4 ± 0.2 days) and B×H cows (20.1 ± 0.4 days). Two (in 79% of estrous cycles) or three (in 21% of cycles) follicular waves per IOI were observed and IOI was shorter (P 0.10) in both genotypes (15.8 ± 1.5 mm in Boran and 19.4 ± 2.9 mm in B×H). Boran cows possessed a greater (P<0.001) total number of ovarian follicles than B×H cows and both genotypes displayed more (P<0.05) activity on their right than left ovary. Results...

Twenty post-partum Balady goats (primiparous n=10; pluriparous, n=10) were slaughtered at differe... more Twenty post-partum Balady goats (primiparous n=10; pluriparous, n=10) were slaughtered at different intervals between the day of parturition and day 37 post-partum (PP). Macroscopic changes included uteri weight and volume, and length of uterine body and horns were measured. Histomorphomolgical changes in the endometrial epithelium cell types and height, glands, stroma and caruncles were recorded. Macroscopic study indicated three phases of uterine regression. A fast involution phase extended from the time of parturition to day 7 PP, a second moderately fast uterine involution phase, which extended until day 13 PP and a slow phase that ended by day 19 PP. By day 19 PP, weight and volume were reduced to less than 5 % of the weight recorded on day 1 PP, discharges completely cleared, caruncles completely regressed, horns became symmetrical and the uteri in these animals were not different from uteri of the nulliparous goats. Similarly, microscopic changes were classified into three ov...

The study presented valuable information on live pigs’ marketing, buyers’ characteristics, purpos... more The study presented valuable information on live pigs’ marketing, buyers’ characteristics, purpose of buying pigs, partnerships among market actors, trend of swine business and motivational drivers in swine sector of Ethiopia. A total of 66 swine farms were selected in six major towns to collect quantitative and qualitative data on the studied parameters. A multi-stage sampling procedure was employed to select sampling areas and respondents. A standardized questionnaire was used to collect the data using person to person interview. Data were analyzed using appropriate statistical procedures of SPSS. On average 10, 40 and 163 pigs per farm per year were sold in small, medium and large scales of production, respectively, and this was statistically significant (P<0.05) across the three scales of production. Brokers (40%), people in informal market (20%) and owners of nearby farms (14.5%) were the main buyers of live pigs in Ethiopia. The study revealed that the main purposes of buyi...

Boran (n=25) and Boran*Holstein (n=11) cows were superovullatedFSH with three doses level (300, 2... more Boran (n=25) and Boran*Holstein (n=11) cows were superovullatedFSH with three doses level (300, 250 and 200IU) divided in to morning and afternoon decreasing doses over 4 daysto study the superovulatory response and embryo production potential. Time to estrus, duration of estrus, and CL count were used to determine superovulatory response. Embryos were flushed on Day 16/17 by non-surgical gravitational method and evaluated for development stage, and quality grade. The mean (±SEM) time interval from CIDR withdrawal to onset of estrus was 20.4±1.8 hours, and breed difference was not significant.However, the interval from CIDR removal to onset of estrus was shorter (p=0.01) in cows treated with 250 IU FSH (10.75±3.3 hours) than in cows received 200 or 300 IU. The total CL count was significantly higher (p=0.01) in Boran (10.1CL/cow/cycle) than Boran x Holstein cows (7.2CL/cow/cycle). A mean number of 4.1 and 2.67embryos’/cow were flushed from Boran and Boran*Holstein, respectively. The...

The aims of this study was to see the effect of breed, parity and scheme of collection on the qua... more The aims of this study was to see the effect of breed, parity and scheme of collection on the quality and quantity of OPU derived oocytes and effect of transvaginal ultrasound guided follicular aspiration on subsequent fertility of donor cows. A total of 28 animals (11 Boran and 11 Boran Holstein-Friesian cross for once per week collection, and 7 Boran and 7 Boran Holstein-Friesian cross for twice per week collection) were used in this experiment. A total of 22 animals were evaluated for the effect of the OPU procedure on subsequent reproductive function. In 150 Ovum Pick up sessions, irrespective of collection scheme, breed and parity, 1124 follicle (554 in Boran and 570 in HF crosses) were punctured with a recovery rate of 51.1% in Boran and 48.6% in the crosses. Relatively more follicles were aspirated in crosses compared to Borans although the difference in oocyte recovery rate and quality were not statistically significant. Overall recovery rate was 57.7% in heifers and 42% in ...

አህፅሮት የጥናቱ ዋና ዓሊማ ንፁህ የቦረና ሊሞችና የቦረና ዲቃሊ ሊሞች ተጨማሪ ዕንቁሊል የማኮረትና ፅንስ የመስጠት አቅማቸውን ሇማጥናት የተሰራነው፡፡ ሊሞ... more አህፅሮት የጥናቱ ዋና ዓሊማ ንፁህ የቦረና ሊሞችና የቦረና ዲቃሊ ሊሞች ተጨማሪ ዕንቁሊል የማኮረትና ፅንስ የመስጠት አቅማቸውን ሇማጥናት የተሰራነው፡፡ ሊሞች በሦስት ቡድን ተከፍሇው 300 ፣ 250 እና 200 አይ . ዩ . ኤፍ . ኤስ . ኤች . ሆርሞን ተሰጣቸው፤ ከዚያም የኮርማ ፍሊጎት እስከሚያሳዩበት የወሰደባቸው ጊዜ፣ የኮርማ ፍሊጎት እያሳዩ የሚቆዩት ጊዜ እና ጠቅሊሊ አኮርተው የሇቀቁት ዕንቁሊል ቁጥር በማየት ሇሆርሞኑ የነበራቸው ምሊሽ ተጠንቷል፡፡ ተጨማሪ ዕንቁሊል እንዲያኮርቱ ሇማድረግ ሆርሞን በተሰጣቸው በ 16-17 ቀን ሊይ ፅንሶችን በመሰብሰብ የዕድገታቸው ሁኔታና ጥራት ግምገማ ተደርጓል፡፡ በመጨረሻው ጊዜ ሆርሞን ከተሰጠበት የኮርማ ፍሊጎት እስከሚያሳዩበት ጊዜ በአማካይ 20.4 ሰዓታ የወሰደባቸው ሲሆን በቦረና እና በዲቃሎቻቸው መካከል የጎሊ የሰዓታት ልዩነት አልታየም፡፡ ይሁን እንጂ ከተሰጣቸው ሦስት የተሇያየ የሆርሞን መጠን 250 አይ . ዩ የወሰዱት ቀደም ብሇው በ 10 ሰዓታ ውስጥ የኮርማ ፍሊጎት አሳይተዋል፡፡ የተኮረቱት ዕንቁሊል ቁጥር ሲታይ ቦረናዎች (10.1 ዕንቁሊል ) ከዲቃሎቻቸው የተሸሇ በዛ ያለ አዘጋጅተዋል፡፡ የፅንስ ብዛትም ሲታይ ቦረናዎች 4 ሲሰጡ ዲቃሎቻቸው 2.67 ሰጥተዋል፡፡ ከፅንስ ዕድገትና ጥራት ግምገማ ውጤት ቦረናዎች ሉተሊሇፉ የሚችለ ፅንስ 3.8 ሲሆን የዲቃሎቻቸው 2.67 ነበር፡፡ በመሆኑም በታዩት መስፈርቶች ቦረና ሊሞች ከዲቃሎቻቸው የተሸሇ ዕንቁሊ ማኮረት እንደሚችለና የተሻሇ የዕድገት ደረጃና ጥራት ያሇው ፅንስ መስጠት የሚችል አቅም እንዳሇቸው ታይቷል፡፡ Abstract Boran (n=25) and Boran*Holstein (n=11) cows were superovullatedFSH with three doses level (300, 2...

Dissertation submitted to the College of Veterinary Medicine and Agriculture of Addis Ababa Unive... more Dissertation submitted to the College of Veterinary Medicine and Agriculture of Addis Ababa University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Veterinary Obstetrics and Gynecology

Twenty post-partum Balady goats (primiparous n=10; pluriparous, n=10) were slaughtered at differe... more Twenty post-partum Balady goats (primiparous n=10; pluriparous, n=10) were slaughtered at different intervals between the day of parturition and day 37 post-partum (PP). Macroscopic changes included uteri weight and volume, and length of uterine body and horns were measured. Histomorphomolgical changes in the endometrial epithelium cell types and height, glands, stroma and caruncles were recorded. Macroscopic study indicated three phases of uterine regression. A fast involution phase extended from the time of parturition to day 7 PP, a second moderately fast uterine involution phase, which extended until day 13 PP and a slow phase that ended by day 19 PP. By day 19 PP, weight and volume were reduced to less than 5% of the weight recorded on day 1 PP, discharges completely cleared, caruncles completely regressed, horns became symmetrical and the uteri in these animals were not different from uteri of the nulliparous goats. Similarly, microscopic changes were classified into three ove...

Response to the superovulatory hormone treatments varied for the type of breed and doses of super... more Response to the superovulatory hormone treatments varied for the type of breed and doses of superovulatory hormone used. Ovarian response of 42 cross bred HF (50%, 75%) and pure dairy cows were evaluated based on ultrasonographic count of CL and embryo recovery for quality assessment. Ovarian response rate was significantly higher (P<0.05) in the crossbreds than in the pure bred cows. The maximum response achieved (CL count, mean ± SE) was 14.6±1.1 and the least with 11.2±1.1, 75% HF at 650IU and pure HF at 800IU, respectively. Significantly higher (p<0.05) number of UFO were collected at a dose of 500 IU while transferable embryos were higher at 650IU in both the 50% HF and 75% HF cows. Pure bred cows responded fairly with more CL and produced higher number of transferable embryos at a dose of 800 IU FSH. In conclusion, the optimal dose for maximum response (CL count) exhibited in cross breed HF cows is 650 IU.

Ethiopian Veterinary Journal

This study aimed to characterize estrus sign/s which best predict the time of ovulation and deter... more This study aimed to characterize estrus sign/s which best predict the time of ovulation and determine ovarian responses to different synchronization protocols and conception rates to fixed-time artificial insemination in Boran*Holstein crossbred heifers. In the first part of the study, twenty-seven heifers were observed for estrus signs (from induced and natural) and the relationship of various estrus signs with ovulation time was evaluated by using ultrasonography. In the second part, 91 Boran*Holstein crossbred heifers were randomly grouped into three groups. Group one heifers (n=28) received 100μg gonadotropin-releasing hormone (GnRH) on day zero (D0), 500μg prostaglandin F2α (PGF2α) on day 7 and 100μg of GnRH on day 9. Group 2 heifers (n=32) were treated as group one but additionally received progesterone as controlled internal drug release (CIDR). Group three heifers (n=31) were treated as those in group 2 but without injection with GnRH on day 0. In all the 3 groups’ insemi...

Ethiopian Veterinary Journal

Boran breed is the most suitable type of cattle breed for arid and semi-arid regions of Ethiopia ... more Boran breed is the most suitable type of cattle breed for arid and semi-arid regions of Ethiopia due to their adaptive characteristics. Understanding their reproductive anatomy is important for successful reproductive management and has many implications for the application of assisted reproductive technology, and interpretation of physiological changes at different stages of their reproductive cycle. In this study, data of the anatomical structures of the reproductive organs of 20 Boran heifers were measured and characterized at different stages of reproduction. The mean (±SE) length (L) of the vagina, cervix, and body of uterus were 13.17±2.98 cm, 7.19±1.28 cm, and 6.70±1.08cm, respectively. The mean (±SE) length of the right uterine horn and oviduct was 18.47 ±2.54 and 18.17 ±1.27cm, respectively and that of the left were 18.05±2.73 and 17.45±1.80 cm, respectively. The mean ±SE weight (W) of right and left ovaries were 2.44±1.51 gm and 2.44±1.51 gm, respectively. The mean ±SE ...

Ethiopian Veterinary Journal

The variation of the dairy breed can determine the success of bovine embryo transfer by influenci... more The variation of the dairy breed can determine the success of bovine embryo transfer by influencing the quantity and quality of in vivo embryo production. In this experiment, output and quality of in vivo produced embryos using semen of progeny tested Holstein Friesian (HF) sire in Boran and HF*Boran F1 cross cows, and semen from purebred Boran sire in HF*Boran F1 cross and Boran cows were evaluated. Boran (n=18) and HF*Boran cross (n=18) breed donor dams were superovulated using a previously optimized follicular stimulating hormone (FSH) (Pluset®) dose regimen: 650 IU for HF*Boran cross and 250 IU for Boran breeds. Each cow was flushed on Day-7 post insemination and embryos were evaluated for their developmental stages and quality. Superovulatory response rates were 88.9% and 83.3%, respectively, for Boran and HF*Boran with no significant (P>0.05) breed differences. Total recovery rates were relatively lower (56.5%) in Boran compared to in HF*Boran (67.4%). The mean (±SE) embr...

Tigrai Agricultural Research Institute (TARI) Ethiopian Institute of Agricultural Research (EIAR)... more Tigrai Agricultural Research Institute (TARI) Ethiopian Institute of Agricultural Research (EIAR) Ethiopian Agricultural Research Council Secretariat (EARCS)

Ethiopian Veterinary Journal

The study was conducted to characterize the follicular dynamics of purebred Boran (Bos indicus) a... more The study was conducted to characterize the follicular dynamics of purebred Boran (Bos indicus) and Boran * Holstein Friesian crossbred heifers during estrous cycles; for use in ovum pick up and in-vitro embryo production. Insight of reproductive physiology of cattle would help to understand and exploit the reproductive potential of elite animals for breed improvement. Follicular development, growth and atresia during estrous cycles were evaluated using a trans-rectal real-time B-mode ultrasound system for three consecutive estrus cycles. Luteal activity was evaluated by serum progesterone level. Follicular aspirations were done to investigate the potential of Boran cattle and their crosses for transvaginal oocyte production; using a vacuum pressure pump and Aloka SSD Prosound-2 ultrasound device. Boran heifers (n=15) manifested two (n = 6, 40%), three (n = 5, 33%), four (n= 3, 20%) and five (n=1, 6.7%) follicular waves. Crossbred heifers (n=14) showed one (n= 2, 14%), two (n= 6, 4...

Tropical Animal Health and Production

International Journal of Livestock Production, 2021

African Journal of Biotechnology, 2016

Twenty post-partum Balady goats (primiparous n=10; pluriparous, n=10) were slaughtered at differe... more Twenty post-partum Balady goats (primiparous n=10; pluriparous, n=10) were slaughtered at different intervals between the day of parturition and day 37 post-partum (PP). Macroscopic changes included uteri weight and volume, and length of uterine body and horns were measured. Histomorphomolgical changes in the endometrial epithelium cell types and height, glands, stroma and caruncles were recorded. Macroscopic study indicated three phases of uterine regression. A fast involution phase extended from the time of parturition to day 7 PP, a second moderately fast uterine involution phase, which extended until day 13 PP and a slow phase that ended by day 19 PP. By day 19 PP, weight and volume were reduced to less than 5% of the weight recorded on day 1 PP, discharges completely cleared, caruncles completely regressed, horns became symmetrical and the uteri in these animals were not different from uteri of the nulliparous goats. Similarly, microscopic changes were classified into three ove...

Ethiopian Veterinary Journal