Timing GnRH Administration with Split-time Artificial Insemination Following Administration of CIDR-based Protocols to Synchronize Estrus and Ovulation in Beef Heifers and Cows

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Total Pages : 75 pages
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Book Synopsis Timing GnRH Administration with Split-time Artificial Insemination Following Administration of CIDR-based Protocols to Synchronize Estrus and Ovulation in Beef Heifers and Cows by : Brianne Elizabeth Bishop

Download or read book Timing GnRH Administration with Split-time Artificial Insemination Following Administration of CIDR-based Protocols to Synchronize Estrus and Ovulation in Beef Heifers and Cows written by Brianne Elizabeth Bishop and published by . This book was released on 2015 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: Historically, adoption of AI within beef herds has increased due to improvements in methods to synchronize estrous and expanded use of fixed-time artificial insemination (FTAI) where all females are inseminated at a predetermined fixed time. Because pregnancy rates are higher among females that exhibit estrus prior to AI, split-time AI was developed as an alternative breeding strategy whereby insemination is delayed 20 to 24 hours (h) for females that fail to express estrus prior to a predetermined fixed time. Three experiments were designed to test hypotheses related to the timing and use of GnRH in breeding programs involving STAI based on results from previously published studies. Estrus was synchronized for heifers in experiment 1 with the 14-d CIDR-PG protocol, and for cows in experiment 2 using the 7-d CO-Synch + CIDR protocol. Females in each treatment that exhibited estrus by 66 h were inseminated at 66 h, whereas AI was delayed 24 h (90 h after PGF2?) for females failing to exhibit estrus by 66 h. Females in treatment 1 received GnRH 66 h after PGF2? irrespective of estrus expression; however, in treatment 2, GnRH was administered coincident with delayed AI only to females not detected in estrus at 66 h. GnRH administered to estrus females at 66 h did not affect AI pregnancy rate; however delaying GnRH to 90 h for non-estrous females at 66 h improved estrous response for cows but not for heifers, with no effect on AI pregnancy rate. A third experiment evaluated pregnancy rates of heifers that failed to exhibit estrus by 90 h after PGF2? following treatment with the 14-d CIDR-PG protocol. Treatments were compared on the basis of whether or not GnRH was administered concurrent with AI, 90 h after PG. There was no effect of treatment on AI pregnancy rate. Collectively, these results indicate: 1) GnRH is not required among females that exhibit estrus prior to AI; 2) delayed administration of GnRH increases total estrous response in cows when STAI is practiced; and 3) GnRH is not required when STAI is practiced in conjunction with the 14-d CIDR-PG protocol in heifers.

Comparison of CIDR-based Protocols to Synchronize Estrus in Beef Heifers

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Book Synopsis Comparison of CIDR-based Protocols to Synchronize Estrus in Beef Heifers by : Nicole Renee Leitman

Download or read book Comparison of CIDR-based Protocols to Synchronize Estrus in Beef Heifers written by Nicole Renee Leitman and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Estrus synchronization and artificial insemination (AI) are reproductive management techniques that allow beef producers to enhance the reproductive efficiency and genetic composition of their cow herd. However, U.S. beef producers have been reluctant to adopt these reproductive management tools, largely due to time and labor. Recent research to synchronize estrus, therefore, has focused on the development of estrus synchronization protocols that facilitate fixed-time AI (FTAI). Although protocols have been developed that allow the successful use of FTAI in beef cows, the same degree of success in beef heifers has not been realized. Additionally, no published research has focused on characterizing the physiological responses to long- and short-term CIDR-based protocols in beef heifers. Experiment 1 evaluated ovulatory response to GnRH and synchrony of estrus and ovulation after PGF2[alpha] (PG) in beef heifers. The CIDR Select and Select Synch + CIDR protocols were evaluated among estrous cycling and prepubertal beef heifers and the CIDR-PG and Select Synch protocols were evaluated among estrous cycling beef heifers. A reduced variance for the intervals to estrus and ovulation was detected for estrous cycling heifers treated with the CIDR Select protocol in comparison to the other 3 treatments. The combined results of the estrous cycling and prepubertal heifers revealed an increased ovulatory response to GnRH for heifers treated with the CIDR Select protocol compared to the Select Synch + CIDR protocol, which ultimately resulted in a reduced variance for interval to estrus and ovulation after PG. Furthermore, no differences within treatment were detected in the variance for interval to estrus or ovulation among estrous cycling and prepubertal heifers treated with the CIDR Select protocol. These results suggest that the CIDR Select protocol may facilitate FTAI more effectively in mixed groups of estrous cycling and prepubertal beef heifers. Experiments 2 and 3 evaluated modifications to the CIDR Select protocol. Estrous cycling beef heifers were used in Exp. 2. The hypothesis tested was that reducing the interval from CIDR removal to GnRH administration by 2 d would facilitate an improvement in the synchrony of estrus after PG. Although a larger number of heifers that were assigned to the 28 d protocol were on d 5 and 6 at the time GnRH was administered, response to GnRH was not improved and synchrony of estrus was not enhanced following PG. In Exp. 3, a second modification to the CIDR Select protocol was evaluated using estrous cycling and prepubertal beef heifers. The hypotheses tested were: 1) reducing the interval from CIDR removal to GnRH may facilitate an improvement in the synchrony of estrus after PG, and 2) the addition of GnRH following CIDR removal is required to improve the synchrony of estrus after PG. Although no difference in estrous response was detected, mean intervals to estrus and variance for interval to estrus differed based on the interaction of treatment length, GnRH, and estrous cyclicity status. The results from Exp. 3 clearly suggest that further evaluation of long-term CIDR-based protocols is required.

Comparison of Controlled Internal Drug Release (CIDR)-based Protocols to Synchronize Estrus and Facilitate Artificial Insemination (AI) in Postpartum Beef Cows

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Total Pages : 79 pages
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Book Synopsis Comparison of Controlled Internal Drug Release (CIDR)-based Protocols to Synchronize Estrus and Facilitate Artificial Insemination (AI) in Postpartum Beef Cows by : Dallas James Wilson

Download or read book Comparison of Controlled Internal Drug Release (CIDR)-based Protocols to Synchronize Estrus and Facilitate Artificial Insemination (AI) in Postpartum Beef Cows written by Dallas James Wilson and published by . This book was released on 2008 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Artificial insemination (AI) and estrous synchronization are reproductive technologies that enable beef producers to efficiently improve herd genetics. The recent development of protocols designed to synchronize estrus and ovulation enable producers to utilize fixed-time AI (FTAI), thus reducing time and labor required to detect estrus. The 7-d Select Synch and CO-Synch + CIDR protocols provide an efficient and effective means to synchronize estrus in postpartum beef cows. Recently a 5-d Select Synch and CO-Synch + CIDR protocol was developed. To date, however, the literature is devoid of information comparing the 7-d and 5-d protocols on the basis of their practical application in the field. Experiment 1 was designed to fully characterize and compare the 7-d and 5-d Select Synch + CIDR protocols. There were no differences between treatments for estrous response, interval to estrus, or the variance for interval to estrus. Additionally, response to GnRH and follicle size at GnRH did not differ between the two treatments, nor were there any differences in synchronized conception or pregnancy rates resulting from AI. Experiment 2 was designed to compare pregnancy rates resulting from fixed-time AI following administration of the 7-d and 5-d CO-Synch + CIDR protocols with FTAI at 66 and72 h. There was no effect of treatment, technician, sire, or location on FTAI pregnancy rates. The results from these experiments indicate that the 7-d and 5-d Select Synch and CO-Synch + CIDR protocols performed comparably on the basis of synchronizing estrus and facilitating pregnancy resulting from FTAI, respectively.

A Comparison of Co-Synch + CIDR and ECP + CIDR as Estrus Synchronization Techniques for Timed Artificial Insemination of Beef Heifers

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Total Pages : 66 pages
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Book Synopsis A Comparison of Co-Synch + CIDR and ECP + CIDR as Estrus Synchronization Techniques for Timed Artificial Insemination of Beef Heifers by : Morgan J. Roberts

Download or read book A Comparison of Co-Synch + CIDR and ECP + CIDR as Estrus Synchronization Techniques for Timed Artificial Insemination of Beef Heifers written by Morgan J. Roberts and published by . This book was released on 2010 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was conducted as an estrus synchronization technique comparison. The objective of this study was to compare the effectiveness of two different estrus synchronization protocols for use in beef heifers. Two CIDR based protocols were utilized in this study, Co-Synch + CIDR (progesterone, gonadotrophin releasing hormone, and prostaglandin) and ECP + CIDR (Estradiol Cypionate, progesterone, prostaglandin, and gonadotrophin releasing hormone). 65 heifers were located on the same farm, however, were separated into three groups for handling ease (Group 1=21, Group 2-23, and Group 3=21). 42 heifers (Group 1=21, Group 2=11, and Group 3=10 were synchronized using the Co-Synch + CIDR technique. Heifers were administered a 2.0 ml injection of GnRH at the time of CIDR insertion. The CIDR implants remained in the heifers for 7 days. A 5.0 ml injection of PGF was administered at the time of CIDR removal. Removal was followed by TAI 52 hours later. At the time of AI heifers received another injection of GnRH. 23 heifers (Group 2=12 and Group 3=11) received the ECP + CIDR protocol. Each heifer received a 0.5 ml injection of ECP at time of CIDR insertion. CIDR remained in heifers for 7 days. All heifers were administered a 5.0 ml shot of PGF at time of CIDR removal. 52 hours after removal, heifers were TAI and were given an injection of GnRH. Conception rates of 57.1%, 18.2 % and 60.0% were achieved with the Co-Synch + CIDR protocol after time artificial insemination. ECP + CIDR resulted in conception rates of 33.3% and 90.9% after timed artificial insemination.

Comparison of Long-term Progestin-based Protocols to Synchronize Estrus in Beef Heifers

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Total Pages : 89 pages
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Book Synopsis Comparison of Long-term Progestin-based Protocols to Synchronize Estrus in Beef Heifers by : Daniel A. Mallory

Download or read book Comparison of Long-term Progestin-based Protocols to Synchronize Estrus in Beef Heifers written by Daniel A. Mallory and published by . This book was released on 2009 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiment 1 evaluated two long-term progestin-based and controlled internal drug release estrus synchronization protocols to determine their potential to facilitate fixed-time artificial insemination in estrous cycling and prepubertal beef heifers. Conception to AI, AI pregnancy, and final pregnancy rates did not differ between treatments. Experiment 2 compared two long-term progestin-based estrus synchronization protocols to evaluate their potential to facilitate fixed-time artificial insemination in estrous cycling and prepubertal beef heifers. Estrous response after PG was greater among CIDR treated heifers compared to MGA treated heifers. Conception to AI, AI pregnancy, and final pregnancy rates did not differ between treatments. In summary, the long-term CIDR protocol compared favorably with the MGA protocol. Experiment 3 was conducted to compare pregnancy rates resulting from fixed-time AI after administration of either one of two long-term CIDR-based protocols. CIDR-GnRH-PG and CIDR-PG treated heifers were fixed-time inseminated at 72 or 66 hr after PG, respectively. Fixed-time AI pregnancy rates tended to be higher among CIDR-PG compared to CIDR-GnRH-PG treated heifers. Final pregnancy rates did not differ between treatments. In summary, both long-term progestin-based protocols were effective in synchronizing estrus prior to fixed-time AI in beef heifers.

Synchronization of Follicular Wave Emergence, Luteal Regression, and Ovulation for Fixed-time Artificial Insemination in Beef Cows and Heifers

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Book Synopsis Synchronization of Follicular Wave Emergence, Luteal Regression, and Ovulation for Fixed-time Artificial Insemination in Beef Cows and Heifers by : Kyle Jeffrey Stutts

Download or read book Synchronization of Follicular Wave Emergence, Luteal Regression, and Ovulation for Fixed-time Artificial Insemination in Beef Cows and Heifers written by Kyle Jeffrey Stutts and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two experiments tested the efficacy of gonadotropin-releasing hormone (GnRH) or estradiol cypionate (ECP) administration in combination with controlled internal drug release (CIDR) inserts on pregnancy rate to fixed-time artificial insemination (FTAI) in beef heifers. In the first experiment, heifers in the two ECP groups received ECP in conjunction with the CIDR insert. The CIDR insert was removed and PGF was administered on either d 7 or 9. Heifers received ECP 24 h after CIDR removal and were inseminated 30 h after ECP. Heifers in the two GnRH groups received GnRH in conjunction with the CIDR insert. Heifers received PGF on either d 6 or 7, and the CIDR insert was removed on d 7. Heifers were inseminated and received GnRH 48 h after CIDR removal. Pregnancy rates to FTAI were higher for heifers treated with GnRH. Pregnancy rate to FTAI was highest for heifers in the GnRH group that received PGF on d 6 and was lowest for the group that received ECP in combination with a 7-d CIDR insert. In the second experiment, heifers received GnRH in conjunction with the CIDR insert. CIDR inserts were removed and PGF was administered on d 7. Heifers were inseminated 60 h later, with one group receiving GnRH at insemination. Pregnancy rate to FTAI was higher for heifers that received GnRHat insemination. The final experiment tested the efficacy of estradiol 17 _(E17) or GnRH in combination with a CIDR insert on pregnancy rate to FTAI in Brahman cows. Either E17 or GnRH was administered in conjunction with the CIDR insert. CIDR inserts were removed on d 7. Cows in the GnRH group received PGF on d 6 and GnRH at insemination which occurred 48 h after CIDR removal. Cows in the E17 group received PGF on d 7, E17 24 h later, and were inseminated 30h after E17 administration. Pregnancy rate to FTAI was higher for cows treated with E17. These data indicate acceptable pregnancy rates were obtained when the CIDR insert was combined with either GnRH in beef heifers or with E17 in Brahman cows.

Evaluation of Long-term CIDR-based Estrus Synchronization Protocols in Primiparous Two-year-old Beef Cows

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Total Pages : 102 pages
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Book Synopsis Evaluation of Long-term CIDR-based Estrus Synchronization Protocols in Primiparous Two-year-old Beef Cows by : Jillian Mae Abel

Download or read book Evaluation of Long-term CIDR-based Estrus Synchronization Protocols in Primiparous Two-year-old Beef Cows written by Jillian Mae Abel and published by . This book was released on 2015 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development and comparison of strategies designed to enhance reproductive management of primiparous two-year-old beef cows coincide with the recent increase in heifer retention and the significant number of younger age females that are now entering the U.S. cow herd. Reproductive management of primiparous two-year-old cows presents a unique challenge in managing a beef herd, since this age group of females typically experiences the highest incidence of reproductive failure. Strategic management of replacement beef heifers and primiparous cows is necessary to ensure their continued long-term reproductive success, which provides the opportunity for beef producers to increase retention rates, reduce input costs, and ultimately enhance production efficiency. Estrus synchronization and artificial insemination (AI) are important management tools available to producers that facilitate genetic improvement and enhance reproductive efficiency. A list of recommended protocols may be used to facilitate fixed-time AI (FTAI) in beef cows and heifers, and we now know that specific protocols perform better among various age classes of females. Short-term controlled internal drug release (CIDR)-based protocols are currently the preferred method to synchronize estrus prior to FTAI in postpartum beef cows. Alternatively, long-term CIDR-based protocols have been used with greater success in beef heifers. Progestin-based estrus synchronization protocols offer the potential to induce estrous cyclicity in anestrous postpartum cows and advance conception date. Experiment 1 was designed to compare the 14-d CIDR-PG (14-d) and 7-d CO-Synch + CIDR (7-d) protocols on the basis of estrous response, pregnancy rates after fixed-time AI (FTAI), and final pregnancy in primiparous two-year-old cows. Cows assigned to 14-d (n = 355) received a CIDR insert on Day 0 with removal on Day 14. Cows assigned to 7-d (n = 349) received GnRH and CIDR inserts on Day 23. On Day 30 CIDRs were removed from 7-d cows and PGF2[alpha] was administered to all cows in each treatment. On Day 33, 66 and 72 h after PGF2[alpha], GnRH was administered concurrent with FTAI. Estrous response at FTAI was higher for 7-d compared to 14-d cows (74% vs 43%, respectively; P

Synchronization of Follicular Wave Dynamics and Ovulation for Fixed-time Artificial Insemination in Cattle

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Book Synopsis Synchronization of Follicular Wave Dynamics and Ovulation for Fixed-time Artificial Insemination in Cattle by :

Download or read book Synchronization of Follicular Wave Dynamics and Ovulation for Fixed-time Artificial Insemination in Cattle written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective was to develop new synchronization protocols that facilitate fixed-time artificial insemination (AI). A series of experiments were designed to evaluate the effects of estradiol and progesterone on gonadotrophin release, follicular wave emergence and ovulation in beef cattle. In ovariectomized cows, a new CIDR-B device increased plasma progesterone to near-luteal concentrations, but for only 2 to 3 days. Injection of 100 mg progesterone increased plasma progesterone approximately 2 ng/mL. Progesterone suppressed plasma LH concentrations but did not affect plasma FSH concentrations. Estradiol, with or without progesterone, resulted in FSH suppression with resurgence (and follicular wave emergence) at an interval that varied according to the estradiol formulation. Estradiol administration following CIDR-B removal resulted in LH release (and ovulation in intact animals). Both estradiol-17Î2 and estradiol benzoate (EB) synchronized ovarian follicular wave emergence in CIDR-Bï¿ư-treated animals and the interval from CIDR-B removal to ovulation (72 to 120 h) was shorter and more synchronous in estradiol-treated animals than in controls. In cattle given a CIDR-B device and estradiol plus progesterone, estradiol treatment following CIDR-B removal 7 days later resulted in acceptable conception rates to fixed-time AI. Estradiol or GnRH at the beginning and end of a 7-day MGA-based synchronization regimen resulted in acceptable pregnancy rates to fixed-time AI. In a single experiment, EB, GnRH or pLH in CIDR-B- or MGA-treated beef heifers effectively synchronized ovulation for fixed-time AI. Pregnancy rates were, on average, 58.0% (range 52.5 to 65.0%). A 6- or 7-d interval from GnRH to PGF in a Cosynch regimen resulted in similar pregnancy rates in cows. The addition of a progestin to a Cosynch or Ovsynch regimen improved pregnancy rates in heifers but not in cows. Synchronization of follicular wave emergence and ovulation in a two-dose PGF-based protocol.

Development of Hormonal Protocals for Synchronization of Ovulation and Timed Artificial Insemination in Dairy Heifers

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Total Pages : 294 pages
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Book Synopsis Development of Hormonal Protocals for Synchronization of Ovulation and Timed Artificial Insemination in Dairy Heifers by : Humberto Rivera

Download or read book Development of Hormonal Protocals for Synchronization of Ovulation and Timed Artificial Insemination in Dairy Heifers written by Humberto Rivera and published by . This book was released on 2004 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Comparison of Long-term CIDR-based Protocols to Synchronize Estrus in Postpartum Beef Cows

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ISBN 13 :
Total Pages : 126 pages
Book Rating : 4.:/5 (876 download)

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Book Synopsis Comparison of Long-term CIDR-based Protocols to Synchronize Estrus in Postpartum Beef Cows by : Justin Michael Nash

Download or read book Comparison of Long-term CIDR-based Protocols to Synchronize Estrus in Postpartum Beef Cows written by Justin Michael Nash and published by . This book was released on 2011 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Estrus synchronization and artificial insemination are two of the most important management practices available to producers to increase reproductive performance in a beef cow-calf operation. Unfortunately, a small number of producers utilize these practices due to increased labor requirements. The use of fixed-time artificial insemination (FTAI) reduces the amount of time and labor required to detect estrus, leading to decreased input requirements. The following experiments were performed in order to compare the use of long-term controlled internal drug release (CIDR) insert-based estrus synchronization protocols prior to FTAI in estrous-cycling and anestrous postpartum beef cows. In experiments 1 and 2, two long-term CIDR-based estrus synchronization protocols were compared on the basis of physiological characteristics, including serum steroid hormone concentrations, estrous response, and follicular dynamics, as well as pregnancy rates resulting from FTAI. From these intensive trials, it was determined that both protocols yielded comparable pregnancy rates and similar physiological responses when used in postpartum beef cows. In experiment 3, the use of either a long- or short-term CIDR-based estrus synchronization protocol was compared prior to FTAI in a large-scale field trial. Results indicated that pregnancy rate resulting from FTAI was similar for both protocols. These data provide preliminary support for the use of long-term CIDR-based estrus synchronization protocols prior to FTAI in postpartum beef cows.

Comparison of Progestin Based Protocols to Synchronize Estrus and Ovulation in Beef Cows

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ISBN 13 :
Total Pages : 174 pages
Book Rating : 4.:/5 (72 download)

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Book Synopsis Comparison of Progestin Based Protocols to Synchronize Estrus and Ovulation in Beef Cows by : Daniel Joseph Schafer

Download or read book Comparison of Progestin Based Protocols to Synchronize Estrus and Ovulation in Beef Cows written by Daniel Joseph Schafer and published by . This book was released on 2005 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Bovine Reproduction

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Publisher : John Wiley & Sons
ISBN 13 : 111960236X
Total Pages : 1236 pages
Book Rating : 4.1/5 (196 download)

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Book Synopsis Bovine Reproduction by : Richard M. Hopper

Download or read book Bovine Reproduction written by Richard M. Hopper and published by John Wiley & Sons. This book was released on 2021-07-21 with total page 1236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bovine Reproduction A complete resource for practical, authoritative information on all aspects of bovine theriogenology The newly revised Second Edition of Bovine Reproduction delivers a comprehensive overview of all major issues in bovine reproduction. Written by leading experts in the subject, the book is an indispensable reference for any veterinarian dealing with bovine fertility. Bovine Reproduction is divided into sections on the bull, the cow, the neonate, and assisted reproduction techniques. New chapters cover new gene manipulation technologies, managing problem donors, lameness, and more. Outdated and redundant information from the First Edition has been removed and replaced by coverage of new diseases, technologies, procedures, techniques, and approaches to fertility problems. A new companion website provides images and tables from the book in PowerPoint format. In addition to more than 675 full-color images, readers will also benefit from: A thorough discussion of the anatomy and physiology of the bull, including the endocrine and exocrine function of bovine testes and the thermoregulation of the testes An exploration of breeding and health management of bulls, including the evaluation of breeding soundness and ultrasound examination of the reproductive tract An examination of the anatomy, physiology, and the breeding and health management of cows, including fetal programming, the reproductive tract microbiome, and a section on obstetrics and reproductive surgery A review of the management of both critical care of the neonate and effective colostrum assessment and provision An introduction to assisted and advanced reproductive technologies A practical and comprehensive reference, Bovine Reproduction is a must-have purchase for bovine practitioners, theriogenologists, animal scientists, veterinary students, and residents with an interest in cattle.

Comparison of Long-term CIDR-based Protocols to Synchronize Estrus and Ovulation Prior to Fixed-time Artificial Insemination in Postpartum Beef Cows

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Total Pages : 79 pages
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Book Synopsis Comparison of Long-term CIDR-based Protocols to Synchronize Estrus and Ovulation Prior to Fixed-time Artificial Insemination in Postpartum Beef Cows by : Neal Timothy Martin

Download or read book Comparison of Long-term CIDR-based Protocols to Synchronize Estrus and Ovulation Prior to Fixed-time Artificial Insemination in Postpartum Beef Cows written by Neal Timothy Martin and published by . This book was released on 2012 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Synchronization and Ovarian Development in Dairy Cows and Heifers

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ISBN 13 :
Total Pages : 140 pages
Book Rating : 4.:/5 (982 download)

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Book Synopsis Synchronization and Ovarian Development in Dairy Cows and Heifers by : Rebecca L. J. Coral Escalante

Download or read book Synchronization and Ovarian Development in Dairy Cows and Heifers written by Rebecca L. J. Coral Escalante and published by . This book was released on 2012 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reproductive management is an important factor for improving reproductive efficiency in the dairy industry. Reproductive efficiency affects the profitability of the dairy herd by decreasing days not pregnant and increasing milk produced in a cow's lifetime. There are many reproductive programs used to synchronize the estrous cycle. Prostaglandin F2[alpha] (PGF2[alpha])-based programs synchronize estrus before artificial insemination (AI) after observed estrus. Some disadvantages to PGF2[alpha]-based reproductive programs are time requirements necessary for estrus detection (2 to 3 times/d for about 30 min) and lack of estrus activity observed in dairy cows (only about 40% will show estrus). An advantage to PGF2[alpha]-based reproductive programs is acceptable conception rates (about 45 to 60%) that can surpass timed AI (TAI). Reproductive programs that employ TAI are achieved by synchronization of ovulation with a series of PGF2[alpha] and gonadotropin releasing hormone (GnRH) injections followed by insemination 16 h later. Some of the advantages to synchronization of ovulation followed by TAI are: no estrus detection and acceptable conception rates (40 to 50%). Many reproductive programs include a presynchronization step. The advantage to presynchronization is a tightened synchrony by getting more cows and heifers in the same stage of the estrous cycle before estrous synchronization and AI or TAI. There are a variety of presynchronization methods used in cattle. One of the most common programs is two injections of PGF2[alpha] 14 d apart 12 d before initiation of Ovsynch (d 0 GnRH, 7 d, PGF2[alpha], 56 h, GnRH, 16 h, TAI) (Moreira et al., 2001). Another is double Ovsynch where the Ovsynch program is administered 7 d before another Ovsynch program (Giordano et al., 2012). Long-term progestogens can also be used as a means to presynchronize the estrous cycle and has been successful in beef cows and heifers. Long term progestogens, such as a CIDR (controlled internal drug release) for 14 d, will suppress estrus, inhibit ovulation, and induce the development of a persistent dominant follicle that can ovulate after CIDR removal (Ahmad et al., 1995; Revah and Butler, 1996; Roche et al., 1999). Ovulation of the dominant follicle allows for cows and heifers to be late in the luteal stage of the estrous cycle before PGF2[alpha] and AI or PGF2[alpha], 56 h, GnRH, 16 h, TAI. Presynchronization has shown to decrease the days to pregnancy. This is an advantage because it will directly affect the number of days a cow is not pregnant and the amount of milk she will produce in her lifetime. The objective of this research was to evaluate pregnancies per AI, ovarian follicular and luteal development of postpartum dairy cows and dairy heifers in response to long term progestin-based programs (14dCIDR) compared with PGF2[alpha]-based programs. Experiment 1 (Chapter 2) evaluated the use of a 14dCIDR-PGF2[alpha] program to a PGF2[alpha]-alone program for synchronizing dairy heifers before AI. Heifers were examined by real-time ultrasonography during treatment to assess the ovarian response. Heifers were also monitored for estrus following presynchronization and treatment of PGF2[alpha] to assess ovulation response. The 14dCIDR-PGF2[alpha] system resulted in more heifers with a larger CL at the time of PGF2[alpha]. This is ideal because of the greater luteolytic effects of PGF2[alpha] has on a more mature CL. The 14dCIDR-PGF2[alpha] heifers were AI and became pregnant sooner compared with the PGF2[alpha]-alone heifers. Experiment 2 (Chapter 3) evaluated the use of a 14dCIDR_TAI program compared with a PGF2[alpha]-based program in grazing dairy cows. The 14dCIDR_TAI program employed synchronization of ovulation before TAI and the PGF2[alpha]-based program employed synchronization of estrus with AI after observed estrus. The evaluation of reproductive efficiency for each program was examined. Cows assigned to the 14dCIDR_TAI program were AI early in the breeding season and were all AI by the end the breeding season compared with the PGF2[alpha]-based program. The PGF2[alpha]-based program had a greater first service conception rate (FSCR) compared with the 14dCIDR_TAI program but did not achieve a greater number of pregnancies after two inseminations. Experiment 3 (Chapter 4) evaluated the use of a 14dCIDR_TAI program compared with another common TAI program (Presynch-Oysynch56) in postpartum lactating dairy cows. Follicular dynamics and luteal development were monitored in both programs. Each program was evaluated for effectiveness to presynchronize the estrous cycle and establish pregnancy. The 14dCIDR_TAI and the Presynch-Ovsynch56 programs were comparable in their effectiveness to presynchronize the estrous cycle and establish pregnancy in cows that were cycling. Non-cycling cows treated with the Presynch-Ovsynch56 program had lesser conception rate compared with those that were cycling. There was no difference in conception rate with non-cycling or cycling cows treated with the 14dCIDR_TAI. Experiment 4 (Chapter 5) evaluated the use of the 14dCIDR_TAI program with or without PGF2[alpha] at CIDR removal. It is possible for cows to still have a CL after the end of the 14dCIDR treatment either due to longer estrous cycles or the cow was early in her estrous cycle when the CIDR was inserted. The addition of PGF2[alpha] may help improve the synchrony and conception rates after presynchronization of the estrous cycle before TAI. The addition of the PGF2[alpha] at CIDR removal demonstrated an increase in the number of cows that showed estrus after presynchronization but conception rates were comparable. Overall, the use of the 14dCIDR as means to presynchronize the estrous cycle has been demonstrated as an effective way to enhance the synchrony and decrease the interval to pregnancy in dairy cows and heifers.

Economic Implications of Estrus Synchronization Protocol Choice in a University Cattle Herd

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ISBN 13 : 9780355081220
Total Pages : 67 pages
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Book Synopsis Economic Implications of Estrus Synchronization Protocol Choice in a University Cattle Herd by : Haile Elizabeth Townsend

Download or read book Economic Implications of Estrus Synchronization Protocol Choice in a University Cattle Herd written by Haile Elizabeth Townsend and published by . This book was released on 2017 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study was to produce a cost-benefit analysis comparing the economic outcome of a fixed-timed artificial insemination (FTAI) estrus synchronization protocol to other methods using estrus detection. Angus and Simmental, crossbred cows (n = 88) managed at the Illinois State University (ISU) research farm (Lexington, IL) were randomly assigned to one of three treatment protocols: 7-day CoSynch plus CIDR, Select Synch plus CIDR and Select Synch. The CoSynch regimen (FTAI) included (n = 29): GnRH (Cystorelin RTM) at 2.0 mL (I.M.) and progesterone (CIDR) at 1.38 g (intravaginal) on day 0; PGF2alpha (LutalyseRTM) at 5.0 mL (I.M.) on day 7; GnRH at 2.0 mL (I.M.) 60 to 66 hours post PGF2alpha ; and timed artificial insemination (TAI) at the time of the second GnRH administration. The Select Synch with CIDR regimen (SSC) included the same drug administration as the CoSynch protocol with the exception of the second dose of GnRH. Cows (n = 29) received AI at the time of detected estrus following the application of a heat detection patch and administration of PGF2alpha. The Select Synch regimen (SS) included (n = 29): GnRH at 2.0 mL (I.M.) on day 0; PGF2alpha at 5.0 mL (I.M.) and heat patch on day 7; and AI at the time of estrus detection following PGF 2alpha. Cost-benefit analysis included cost of time and labor, AI supplies, protocol products, pregnancy diagnosis, clean-up bulls, and culling. Pregnancy rates were similar between all three protocols (P = 0.7032). Net cost was calculated by subtracting the returns received following cull sales and average calf prices per treatment, from the net cost of each protocol. Net cost during the field study for the FTAI regimen was $169.46/cow, $173.38/cow for the SSC regimen, and $162.59/cow following the SS protocol (P

Optimizing a Timed Artificial Insemination Protocol in Lactating Dairy Cows

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Total Pages : 272 pages
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Book Synopsis Optimizing a Timed Artificial Insemination Protocol in Lactating Dairy Cows by : Denise Joanne Brusveen

Download or read book Optimizing a Timed Artificial Insemination Protocol in Lactating Dairy Cows written by Denise Joanne Brusveen and published by . This book was released on 2007 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Synchronization of Estrus in Beef Heifers and Cows with GnRH And/or CIDR-based Protocols

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Total Pages : 80 pages
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Book Synopsis Synchronization of Estrus in Beef Heifers and Cows with GnRH And/or CIDR-based Protocols by : Gonzalo Barquero

Download or read book Synchronization of Estrus in Beef Heifers and Cows with GnRH And/or CIDR-based Protocols written by Gonzalo Barquero and published by . This book was released on 2004 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: