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López-Gatius F. Ovarian response to prostaglandin F 2α in lactating dairy cows: a clinical update. J Reprod Dev 2021; 68:104-109. [PMID: 34980770 PMCID: PMC8979807 DOI: 10.1262/jrd.2021-119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Prostaglandin F2α (PGF2α) and its analogs are used to induce luteolysis in estrus synchronization programs to terminate unwanted pregnancies or to promote ovulation in certain cow subpopulations. In the past few decades, the luteolytic dose of PGF2α has remained unchanged. This review explores the clinical implications of increasing the standard dose for these applications in high-producing dairy cows. Ultrasonography may assist in selecting the most appropriate PGF2α dose and improve the results. A reference has been used for PGF2α for promoting ovulation in herds showing poor reproductive performance.
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Affiliation(s)
- Fernando López-Gatius
- Agrotecnio Centre, University of Lleida, 25198 Lleida, Spain.,Transfer in Bovine Reproduction SLu, 22300 Barbastro, Spain
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2
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Noronha IM, Cooke RF, Martins CFG, Oliveira Filho RV, Pohler KG, Vasconcelos JLM. Administering an additional prostaglandin F 2α injection to Bos indicus beef cows during a treatment regimen for fixed-time artificial insemination. Anim Reprod Sci 2020; 219:106535. [PMID: 32828410 DOI: 10.1016/j.anireprosci.2020.106535] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/29/2020] [Accepted: 07/01/2020] [Indexed: 11/27/2022]
Abstract
Two experiments were conducted to evaluate if an additional prostaglandin F2α (PG) injection during an estradiol-based estrous synchronization treatment regimen affects pregnancy rates resulting from fixed-time artificial insemination (FTAI) in Nelore cows. In Experiment 1, 1039 cows were administered estradiol benzoate and an intravaginal progesterone releasing device (CIDR) on d -11, an injection of PG on d -4, with CIDR removal and administration of estradiol cypionate and eCG occurring on d -2, and FTAI on d 0. Cows were administered an additional injection of PG (PG2) or saline (PG1) on d -2. Percentage pregnancy per FTAI on d 30 was greater (P = 0.01) in cows of the PG2 than PG1 group (54.5 % and 46.6 %, respectively). In Experiment 2, there was use of the same treatment regimen for estrous synchronization of 934 cows as that for Experiment 1 followed by FTAI, with there being diagnosis of whether cows had or did not have a corpus luteum on d -4. Response to estrous synchronization, largest follicle diameter at FTAI, and pregnancy per FTAI were greater (P ≤ 0.05) in cows of the PG2 than PG1 group with a body condition score (BCS) < 5.0 at FTAI (81.2 % and 72.6 %, 11.9 and 11.2 mm, 55.5 and 45.6 %; respectively). These treatment responses did not differ (P ≥ 0.18) in cows with BCS ≥ 5.0. Collectively, results indicate that treatment with PG2 increased pregnancy per FTAI in B. indicus cows deficient in body energy reserves, by enhancing follicle development and estrous synchronization response.
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Affiliation(s)
- Isabella M Noronha
- School of Veterinary Medicine and Animal Science, Sao Paulo State University (UNESP), Botucatu, 18168-000, Brazil
| | - Reinaldo F Cooke
- Department of Animal Science, Texas A&M University, College Station, TX, 77843-2471, USA.
| | | | | | - Ky G Pohler
- Department of Animal Science, Texas A&M University, College Station, TX, 77843-2471, USA
| | - José L M Vasconcelos
- School of Veterinary Medicine and Animal Science, Sao Paulo State University (UNESP), Botucatu, 18168-000, Brazil.
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3
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Lopes FR, Silva LM, Zimpel R, Munhoz AK, Vieira-Neto A, Pereira MHC, Poindexter M, Gambarini ML, Thatcher WW, Vasconcelos JLM, Santos JEP. Prostaglandin F 2α influences pre-ovulatory follicle characteristics and pregnancy per AI in anovular dairy cows. Theriogenology 2020; 153:122-132. [PMID: 32454318 DOI: 10.1016/j.theriogenology.2020.04.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/08/2020] [Accepted: 04/29/2020] [Indexed: 11/29/2022]
Abstract
Objectives were to determine the effects of a dose of PGF2α administered 2 days before timed artificial insemination (AI) on LH pulsatility, characteristics of the pre-ovulatory follicle, and pregnancy per artificial insemination (P/AI) in anovular dairy cows, particularly in cows not subjected to hyperthermia. In experiment 1, 2,011 lactating Holstein cows had ovaries scanned by ultrasound to determine corpus luteum (CL) presence and only those without a CL in two consecutive exams were enrolled (n = 437). Cows had the estrous cycle synchronized with an estradiol-progesterone based protocol starting on experiment Day -11 and timed AI on Day 0. Cows were assigned randomly to receive a single dose of 25 mg of PGF2α as dinoprost on Day -4 (1PGF, n = 222) or two doses of 25 mg each of PGF2α, one on Day -4 and one on Day -2 (2PGF, n = 215). Rectal temperatures were evaluated on the day of AI and 7 days later and cows were classified as being normothermic (<39.1 °C) or hyperthermic (≥39.1 °C). Ovulatory responses and P/AI were determined. In experiment 2, cows with regressed CL were exposed to low concentrations of progesterone and then randomly assigned to the same estrous synchronization protocol and treatments, 1PGF (n = 28) and 2PGF (n = 28). Blood was sampled and analyzed for concentrations of progesterone, and for concentrations of LH and 13,14-dihydro-15-keto-PGF2α metabolite (PGFM) every 15 min starting 1 h before to 6 h after treatments and then every 2 h from 12 to 59 h after treatments. The pre-ovulatory follicle was aspirated 44 h after treatments and concentrations of estradiol quantified. In experiment 1, treatment of anovular cows with a second dose of PGF2α increased P/AI in normothermic cows (19.8 [18/91] vs. 38.8% [31/80]), but not in hyperthermic cows. Synchronization was not affected by treatment, but it was greater for normothermic than hyperthermic cows (87.1 [149/171] vs. 77.8% [207/266]). When only synchronized cows were evaluated, the same responses were observed; treatment with 2PGF increased P/AI compared with 1PGF in normothermic cows (23.1 [18/78] vs. 43.7% [31/71]), but not in hyperthermic cows. In experiment 2, administration of 25 mg of dinoprost in 2PGF resulted in concentrations of PGFM 26-fold greater than 1PGF in the first 6 h after treatment (48 vs. 1,242 pg/mL). Cows receiving 2PGF had smaller basal LH concentration (0.57 vs. 0.46 ng/mL) and less frequent LH pulses (4.5 vs. 3.9 pulses/6 h), but duration of the LH surge was longer for 2PGF than 1PGF (13.1 vs. 15.5 h). Treatment with 2PGF increased the diameter and volume of the pre-ovulatory follicle, and concentration of estradiol (115 vs. 262 ng/mL) and total follicular estradiol content (124 vs. 505 ng) compared with 1PGF. Collectively, these results suggest that PGF2α has a role in fertility of anovular cows that is unrelated to its luteolytic effect.
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Affiliation(s)
- F R Lopes
- Departamento de Produção Animal, UNESP, Botucatu, São Paulo, 18618-000, Brazil; Department of Animal Sciences, University of Florida, United States
| | - L M Silva
- Department of Animal Sciences, University of Florida, United States
| | - R Zimpel
- Department of Animal Sciences, University of Florida, United States
| | - A K Munhoz
- Departamento de Produção Animal, UNESP, Botucatu, São Paulo, 18618-000, Brazil
| | - A Vieira-Neto
- Department of Animal Sciences, University of Florida, United States
| | - M H C Pereira
- Departamento de Produção Animal, UNESP, Botucatu, São Paulo, 18618-000, Brazil
| | - M Poindexter
- Department of Animal Sciences, University of Florida, United States
| | - M L Gambarini
- Department of Animal Sciences, University of Florida, United States
| | - W W Thatcher
- Department of Animal Sciences, University of Florida, United States; DH Barron Reproductive and Perinatal Biology Research Program, University of Florida, 32611-0910, United States
| | - J L M Vasconcelos
- Departamento de Produção Animal, UNESP, Botucatu, São Paulo, 18618-000, Brazil
| | - J E P Santos
- Department of Animal Sciences, University of Florida, United States; DH Barron Reproductive and Perinatal Biology Research Program, University of Florida, 32611-0910, United States.
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Mohammadi A, Seifi HA, Farzaneh N. Effect of prostaglandin F2α and GnRH administration at the time of artificial insemination on reproductive performance of dairy cows. VETERINARY RESEARCH FORUM : AN INTERNATIONAL QUARTERLY JOURNAL 2019; 10:153-158. [PMID: 31338149 PMCID: PMC6626648 DOI: 10.30466/vrf.2018.87502.2136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/25/2018] [Indexed: 11/16/2022]
Abstract
The present study aimed to determine the effect of administrating prostaglandin F2α (PGF2α) and GnRH at the time of artificial insemination (AI) on the pregnancy per artificial insemination (P/AI) and the pregnancy survival rate of dairy cows. A number of 830 lactating Holstein cows were randomly divided into four groups. Cows in group 1 (n=200) treated with 150 µg d-cloprostenol. In group 2 (n=212), cows received 10 µg buserelin acetate, and group 3 (n=205) was treated with both 150 µg d-cloprostenol and 10 µg buserelin acetate. In addition, 213 cows were assigned as control group which received normal saline as placebo (group 4). To measure progesterone, milk samples were collected at the insemination day and five days later. Pregnancy diagnosis was performed 28 and 60 days after the insemination, and the size and number of corpus luteum (CL) and twin pregnancies were recorded. Hormone therapies had no effect on the P/AI, pregnancy survival rate, and the size and number of CL. The P/AI ratio in groups 1, 2, 3 and 4 were 38.50%, 42.92%, 41.46% and 40.84%, and the pregnancy survival rates in groups 1, 2, 3 and 4 were 84.42%, 86.81%, 88.23% and 83.91%, respectively. The probability of a twin pregnancy was significantly higher in group 1 (15.58%) than other groups. There was no significant difference between groups in terms of the offspring gender. In conclusion, the administration of d-cloprostenol or buserelin acetate at the time of AI had no effect on P/AI and pregnancy survival rate in dairy cattle under no heat stress condition, while the administration of d-cloprostenol increased the probability of twin pregnancies.
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Affiliation(s)
- Abolfazl Mohammadi
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Hesam A Seifi
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Nima Farzaneh
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
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Mirmahmoudi R, Souri M, Prakash B. Comparison of endocrine changes, timing of ovulations, ovarian follicular growth, and efficacy associated with Estradoublesynch and Heatsynch protocols in Murrah buffalo cows (Bubalus bubalis). Theriogenology 2014; 82:1012-20. [DOI: 10.1016/j.theriogenology.2014.07.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 07/15/2014] [Accepted: 07/15/2014] [Indexed: 11/29/2022]
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6
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The use of PGF2α as ovulatory stimulus for timed artificial insemination in cattle. Theriogenology 2014; 81:689-95. [DOI: 10.1016/j.theriogenology.2013.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/25/2013] [Accepted: 11/26/2013] [Indexed: 11/23/2022]
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A mathematical model of the bovine oestrous cycle: simulating outcomes of dietary and pharmacological interventions. J Theor Biol 2012; 313:115-26. [PMID: 22925571 DOI: 10.1016/j.jtbi.2012.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 05/16/2012] [Accepted: 08/08/2012] [Indexed: 11/20/2022]
Abstract
A mathematical model was constructed to simulate the bovine oestrous cycle by using nonlinear differential equations to describe the biological mechanisms which regulate the cycle. The model predicts circulating concentrations of gonadotrophin-releasing hormone, follicle-stimulating hormone, luteinizing hormone, oestradiol, inhibin and progesterone. These hormones collectively provide control and feedback mechanisms between the hypothalamus, pituitary gland and ovaries, which regulate ovarian follicular dynamics, corpus luteum function and ovulation. When follicular growth parameters are altered, the model predicts that cows will exhibit either two or three follicular waves per cycle, as seen in practice. Changes in other parameters allow the model to simulate: effects of nutrition on follicle recruitment and size of the ovulatory follicle; effects of negative energy balance on postpartum anoestrus; and effects of pharmacological intervention on hormone profiles and timing of ovulation. It is concluded that this model provides a sound basis for exploring factors that influence the bovine oestrous cycle in order to test hypotheses about nutritional and hormonal influences which, with further validation, should help to design dietary or pharmacological strategies for improving reproductive performance in cattle.
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Mirmahmoudi R, Prakash BS. The endocrine changes, the timing of ovulation and the efficacy of the Doublesynch protocol in the Murrah buffalo (Bubalus bubalis). Gen Comp Endocrinol 2012; 177:153-9. [PMID: 22433942 DOI: 10.1016/j.ygcen.2012.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Revised: 03/01/2012] [Accepted: 03/02/2012] [Indexed: 11/30/2022]
Abstract
Experiments were conducted to investigate (a) the timing of ovulation and the associated endocrine changes (progesterone, estrogen and LH) during estrous cycle and (b) the efficacy, with respect to the pregnancy rate, in cycling and anestrus in Murrah buffaloes subjected to the Doublesynch protocol during the low breeding season. In experiment 1, 10 cycling buffaloes were administered PGF(2α) on day 0 (without regard to the estrous cycle stage), GnRH on day 2, a second PGF(2α) injection on day 9, and a second GnRH injection on day 11. Transrectal palpation was performed at 2-h intervals after the first and second GnRH treatments until ovulation was detected or for upto 96 h. The plasma progesterone and total estrogen concentrations were determined in blood samples collected at daily intervals starting 2 days before the onset of the protocol and continued until the day of the second detected ovulation. The plasma LH and total estrogen concentrations were measured in blood samples collected at 30-min intervals for 8h following the first and second GnRH injections and thereafter at 2-h intervals until 2h after the detection of ovulation. Ovulation occurred in 9/10 buffaloes (90%) at 22.2 ± 1.2 h (mean ± S.E.M.; range 18.0-26.0 h) and 10/10 buffaloes (100%) at 23.2 ± 1.0 h (mean ± S.E.M.; range 20.0-28.0 h) after the first and second GnRH treatments, respectively. The peak LH concentrations of 99.8 ± 28.5 ng/ml (range 37.8-320.0 ng/ml) and 62.3 ± 11.9 ng/ml (range 20.9-143.9 ng/ml) occurred 2.1 ± 0.3 h (range 1.0-3.5 h) and 2.3 ± 0.3 h (range 0.5-3.0 h) after the first and second GnRH treatments, respectively. The total estrogen concentration gradually increased from the day of both the first and second PGF(2α) administrations until the LH peak (with great variability) and then gradually declined to the basal level, which was reached at the time ovulation was detected. In experiment 2, 10 cycling and 11 non-lactating anestrus buffaloes were subjected to the Doublesynch protocol with timed artificial insemination (TAI) 16 and 24 h after the second GnRH treatment, and 55 cycling buffaloes were inseminated after spontaneous estrus was detected (control group). The pregnancy rates were 60% using TAI on cycling buffaloes (experiments 1 and 2), 55% for anestrus buffaloes (experiment 2), and 27.3% for cycling buffaloes inseminated following spontaneous estrus. The overall pregnancy success rates after the Doublesynch protocol in both cycling and anestrus buffaloes increased by 30.8% compared to spontaneous estrus (58.1% vs. 27.3%). In conclusion, the Doublesynch protocol effectively synchronized ovulation twice (after the first and second GnRH treatments) irrespective of the stage of estrous cycle in Murrah buffaloes. The study also demonstrated that the Doublesynch protocol followed by TAI significantly (P<0.005) enhanced the pregnancy rate in cycling and anestrus buffaloes in comparison to untreated controls during the low breeding season.
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Affiliation(s)
- R Mirmahmoudi
- Reproductive Physiology Laboratory, Division of Dairy Cattle Physiology, National Dairy Research Institute, Karnal, Haryana 132 001, India.
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Oztürk OA, Cirit U, Baran A, Ak K. Is Doublesynch protocol a new alternative for timed artificial insemination in anestrous dairy cows. Theriogenology 2010; 73:568-76. [DOI: 10.1016/j.theriogenology.2009.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 10/19/2009] [Accepted: 10/24/2009] [Indexed: 11/29/2022]
Affiliation(s)
- O A Oztürk
- Department of Reproduction and Artificial Insemination, Faculty of Veterinary Medicine, Istanbul University, Avcilar, Istanbul, Turkey
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Rantala MH, Peltoniemi OAT, Katila T, Taponen J. Effect of GnRH Dose on Occurrence of Short Oestrous Cycles and LH Response in Cyclic Dairy Heifers. Reprod Domest Anim 2009; 44:647-52. [DOI: 10.1111/j.1439-0531.2007.01040.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Neglia G, Natale A, Esposito G, Salzillo F, Adinolfi L, Campanile G, Francillo M, Zicarelli L. Effect of prostaglandin F2α at the time of AI on progesterone levels and pregnancy rate in synchronized Italian Mediterranean buffaloes. Theriogenology 2008; 69:953-60. [DOI: 10.1016/j.theriogenology.2008.01.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 01/13/2008] [Accepted: 01/19/2008] [Indexed: 10/22/2022]
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Waldmann A, Kurykin J, Jaakma U, Kaart T, Aidnik M, Jalakas M, Majas L, Padrik P. The effects of ovarian function on estrus synchronization with PGF in dairy cows. Theriogenology 2006; 66:1364-74. [PMID: 16815540 DOI: 10.1016/j.theriogenology.2006.04.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Revised: 03/30/2006] [Accepted: 04/09/2006] [Indexed: 11/21/2022]
Abstract
Milk progesterone concentration (P4), milk yield, milk composition, ovarian structures and pregnancy status were studied in 108 cows treated with two doses of PGF 14 days apart and inseminated at fixed time (TAI) 80-82 h later. The synchronization protocol was started at 70+/-1.4 days after parturition. Milk P4 profiles revealed that anestrus, failure of luteolysis following treatment with PGF and failure to ovulate following luteolysis were the main reasons for low pregnancy rate with TAI. Anestrous cows had a higher percentage of milk fat (P<0.05) and higher fat to protein ratio (P<0.01), and cows that did not undergo luteolysis had higher milk yield (P<0.05) and lower percentage of milk protein (P<0.05) than cows that responded to PGF treatment. Cows that did not undergo luteolysis and cows that did not ovulate following luteolysis had lower milk P4 during the luteal phase preceding the second PGF injection (P<0.01 and P<0.05, respectively). Pregnancy rates 24 and 47 days after TAI in cows that responded as expected to the synchronization treatment were 62% and 54%, respectively. Pregnancy was precluded in non-responsive cows. The largest follicle at the time of TAI in cows experiencing late embryonic mortality was smaller (P=0.02) than in cows that successfully maintained pregnancy. Results suggest that a primary reason for low pregnancy rate in dairy cows after administration of PGF and TAI is inappropriate ovarian function prior to, or following treatment.
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Affiliation(s)
- Andres Waldmann
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 62 Kreutzwaldi St., 51014 Tartu, Estonia.
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López-Gatius F, Yániz JL, Santolaria P, Murugavel K, Guijarro R, Calvo E, López-Béjar M. Reproductive performance of lactating dairy cows treated with cloprostenol at the time of insemination. Theriogenology 2004; 62:677-89. [PMID: 15226022 DOI: 10.1016/j.theriogenology.2003.11.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2003] [Revised: 11/15/2003] [Accepted: 11/16/2003] [Indexed: 11/26/2022]
Abstract
The effect of intravenous cloprostenol treatment at the time of insemination on reproductive performance was consecutively evaluated in three different subpopulations of high producing lactating dairy cows: Study (1) early postpartum synchronized and fixed-time inseminated (about 50 days in milk) cows (n = 379: 187 control and 192 treated cows); Study (2) presumed high fertility cows first inseminated between 90 and 120 days postpartum (n = 248: 124 control and 124 treated cows); and Study (3) heat stressed repeat breeder cows (n = 183: 93 control and 90 treated cows). Data were analyzed using multiple regression methods. Study 1: Parity (primiparous versus multiparous), milk production, body condition score at AI, insemination season (cool versus warm period) and treatment were included in the analysis as potential factors affecting ovulation, double ovulation, return to estrus, and pregnancy to first AI and to second AI (first AI plus return AI) rates. Logistic regression analysis indicated that the final model for ovulation rate only included the interaction (P = 0.002) between insemination season and treatment. Cloprostenol treatment at insemination led to a 4.2-fold increase in the ovulation rate in cows inseminated during the warm period. There were no significant effects of treatment, parity, milk production, body score or the insemination season on the return to estrus rate. The only variables included in the final logistic model for double ovulation and pregnancy to first AI rates were treatment and season, respectively. Treatment led to a 2.6-fold increase (P = 0.001) in the double ovulation rate, whereas cows inseminated in the warm period were 2.1 times less likely (P = 0.007) to become pregnant at first AI compared to those inseminated in the cool season. The variables included in the final logistic model for the pregnancy rate to second AI were treatment and season. Cloprostenol given at AI increased the risk of pregnancy 1.9 times (P = 0.002), and cows inseminated during the warm season were two times less likely to become pregnant (P = 0.003). No significant interactions were found among these three dependent variables (double ovulation and pregnancy to first and to second AI rates). Study 2: Logistic regression analysis of all the dependent variables: return to estrus, and pregnancy to first and to second AI (first AI plus return to AI) rates indicated no significant effects of treatment, parity, days in milk, milk production or body score at AI. No significant interactions were found. Study 3: The final model for the pregnancy rate only included the interaction between parity (primiparous versus multiparous) and treatment. Days in milk, milk production and insemination number showed no significant effect on pregnancy rate. Cloprostenol treatment at insemination increased the pregnancy rate in primiparous repeat breeder cows (odds ratio: 3.6). The treatment group and parity showed significant (P < 0.0001) interaction. This interaction suggests that cloprostenol treatment of primiparous cows at insemination might enhance pregnancy yet have no effect in multiparous cows. Our findings indicate that cloprostenol administered at insemination promotes ovulation and double ovulation in lactating dairy cows. Cloprostenol treatment showed no benefit in cows with acceptable reproductive performance, suggesting that cloprostenol treatment at AI may only be useful in cows in which stress factors affect ovulation and in repeat breeder cows.
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Affiliation(s)
- F López-Gatius
- Department of Animal Production, University of Lleida, Lleida, Spain.
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Corbet NJ, Miller RG, Bindon BM, Burrow HM, D'Occhio MJ, Entwistle KW, Fitzpatrick LA, Wilkins JF, Kinder JE. Synchronization of estrus and fertility in zebu beef heifers treated with three estrus synchronization protocols. Theriogenology 1999; 51:647-59. [PMID: 10729049 DOI: 10.1016/s0093-691x(99)00003-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effects on estrus and fertility of 3 estrus synchronization protocols were studied in Brahman beef heifers. In Treatment 1 (PGF protocol; n=234), heifers received 7.5 mg, i.m. prostianol on Day 0 and were inseminated after observed estrus until Day 5. Treatment 2 (10-d NOR protocol; n = 220) consisted of norgestomet (NOR; 3 mg, s.c. implant and 3 mg, i.m.) and estradiol valerate (5 mg, i.m.) treatment on Day -10, NOR implant removal and 400 IU, i.m. PMSG on Day 0, and AI after observed estrus through to Day 5. Treatment 3 (14-d NOR+PGF protocol; n = 168) constituted a NOR implant (3 mg, sc) on Day -14, NOR implant removal on Day 0, PGF on Day 16, and AI after observed estrus through to Day 21. All heifers were examined for return to estrus at the next cycle and inseminated after observed estrus. The heifers were then exposed to bulls for at least 21 d. During the period of estrus observation (5 d) after treatment, those heifers treated with the PGF protocol had a lower (P<0.01) rate of estrual response (58%) than heifers treated with the 10-d NOR (87%) or 14-d NOR+PGF (88%) protocol. Heifers treated with the 10-d NOR protocol displayed estrus earlier and had a closer synchrony of estrus than heifers treated with either the PGF or the 14-d NOR+PGF protocol. Heifers treated with the 14-d NOR+PGF protocol had higher (P<0.05) conception and calving rates (51 and 46%) to AI at the induced estrus than heifers treated with the PGF (45 and 27%) or the 10-d NOR (38 and 33%) protocol. Calving rate to 2 rounds of AI was greater (P<0.05) for heifers treated with the 14-d NOR-PGF (50%) protocol than heifers treated with the 10-d NOR (38%) but not the PGF (43%) protocol. Breeding season calving rates were similar among the 3 protocols. The results show that the 14-d NOR+PGF estrus synchronization protocol induced a high incidence of estrus with comparatively high fertility in Brahman heifers.
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Affiliation(s)
- N J Corbet
- Cooperative Research Center for the Cattle and Beef Industry (Meat Quality), Rockhampton, Australia
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