Two melatonin treatments improve the conception rate after fixed‐time artificial insemination in beef heifers following synchronisation of oestrous cycles using the CoSynch ‐56 protocol

2021 ◽  
Author(s):  
L Guo ◽  
M Li ◽  
X Gao ◽  
Y Yang ◽  
J Zhao ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Fixed Time ◽  
Conception Rate ◽  
Beef Heifers

Oestrus synchronisation and fixed time artificial insemination in beef heifers

2010 ◽  
Vol 50 (7) ◽  
pp. 670
Author(s):  
Daniel Cavestany ◽  
Daniela Crespi ◽  
Alvaro Fernandez
Keyword(s):  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Conception Rate ◽  
Control Group ◽  
Beef Heifers ◽  
Follicular Size ◽  
Follicle Size ◽  
And Control

To compare two oestrus synchronisation protocols in beef heifers presynchronised with two prostaglandin F2α (PG) treatments, 36 h after the second PG treatment one group (hCG-OB group; n = 112) received 250 IU of hCG and 0.5 mg of oestradiol benzoate (OB) followed by fixed time artificial insemination (FTAI) 30 h later. Additional oestrus detection (OD) and artificial insemination (AI) was done in this group for 3 days after FTAI; heifers rebred during this period were considered open to the FTAI. The Control group (n = 112) received only OD and AI for 6 days after the second PG treatment. Follicular size was measured at the time of AI in a subsample of heifers (59 in the hCG-OB group and 34 in the Control group). Results were evaluated separately either considering heifers pregnant at FTAI or those pregnant at FTAI + 3-day OD + AI. The FTAI conception rate was 45.5 vs 76.5% for the Control group (P < 0.0001) and pregnancy rates were 45.5 and 67.0% (P = 0.0014); FTAI + OD + AI conception rates were 63.4 and 76.2% (P = 0.0404) and pregnancy rates 63.4 and 62.8% (P = 0.5719) (hCG-OB and Control groups, respectively). There was a significant correlation (r = 0.713, P < 0.01) between follicle size at FTAI and pregnancy in the hCG-OB group, but not in the Control group (r = 0.3465, P > 0.1). In conclusion, acceptable synchronised conception rate and pregnancy rate were obtained by using this protocol, and the results were improved by complementing it with OD + AI for 3 days after FTAI.

scholarly journals Effects on Synchronization and Reproductive Efficiency of Delaying the Removal of the Intravaginal Progesterone Device by 24 h in the 5d Co-synch Protocol in Heifers

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 849
Author(s):  
Aitor Fernandez-Novo ◽  
Sergio Santos-Lopez ◽  
Jose Luis Pesantez-Pacheco ◽  
Natividad Pérez-Villalobos ◽  
Ana Heras-Molina ◽  
...  
Keyword(s):  
Animal Welfare ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Reproductive Efficiency ◽  
Beef Heifers ◽  
Animal Management ◽  
Commercial Farms ◽  
Beef Herds ◽  
Farm Economics

In beef herds, increasing animal welfare, improving reproductive performance and easing animal management are key goals in farm economics. We explored whether delaying the removal of the intravaginal progesterone device by 24 h in heifers synchronized with a 5d Co-synch 72-h protocol could improve reproductive efficiency of fixed-time artificial insemination (FTAI). In experiment 1, we examined the total synchronization rate (TSR) in cycling Holstein heifers. Heifers (13.4 ± 0.69 mo.) were randomly assigned to the standard 5d Co-synch 56-h protocol (5dCo56; n = 10), 5d Co-synch 72-h (5dCo72; n = 17), or the modified 5d Co-synch 72-h protocol, in which removal of the progesterone device was delayed by 24 h (6dCo48; n = 19). In experiment 2, 309 cycling beef heifers on 18 commercial farms were subjected to the 5d Co-synch 72-h or 6-d Co-synch 48-h protocol and conception rate (CR) studied. In experiment 1, the three protocols led no differences on TSRs of 80.0% (5dCo56), 88.2% (5dCo72), and 89.5% (6dCo48). In experiment 2, the CR from the beef heifers, observed during two consecutive reproductive seasons did not differ: 59.7% for 5dCo72 and 62.0% for 6dCo48 (p = 0.907). Therefore, delaying removal by 24 h provides satisfactory results without reducing reproductive efficiency of heifers.

Response of beef heifers and non-suckling beef cows to different oestrous synchronization protocols

2002 ◽  
Vol 74 (3) ◽  
pp. 547-552 ◽  
Author(s):  
D. Cavestany ◽  
N. Negrin ◽  
R. Negrin ◽  
J. F. Groth
Keyword(s):  
Beef Cattle ◽  
Medroxyprogesterone Acetate ◽  
Artificial Insemination ◽  
Experimental Period ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Gnrh Analogue ◽  
Beef Heifers

AbstractThe objective was to evaluate different oestrous synchronization schemes in beef cattle under range conditions. In experiment 1, 202 heifers averaging 26 months of age were assigned randomly to three treatments: (a) GnRH-PG. (no. = 44) day 0 (D0): injection of GnRH; D7: injection of PGF2α; D0 to D25 oestrous detection (OD) and artificial insemination (AI); (b) OD-PG. (no. = 45) D0 to D4; OD + AI; D5: injection of PGF2α; D5 to D25 OD + AI; and (c)Ovsynch. (no. = 113) D0: injection of GnRH; D7: injection of PGF2α; D9: injection of GnRH and 16 h later AI at fixed time. In experiment 2, 318 non-suckling cows were assigned randomly to three treatments: (a) GnRH-PG. (no. = 106) D0: injection of GnRH; D7: injection of PGF2α; D0 to D25 OD + AI; (b) GnRH-MAP-PG. (no. = 106) D0: injection of a GnRH analogue and insertion of an intravaginal sponge impregnated with 250 mg of medroxyprogesterone acetate; D7: injection of PGF2α and sponge withdrawal; D0 to D25 OD + AI; (c) controls. (no. = 106) OD and AI. The experimental period lasted 25 days and, with exception of the Ovsynch treatment, oestrous detection was carried out twice a day (a.m./p.m.) and inseminations performed 12 h later. The pregnancy rates assessed by ultrasonography 30 days after AI were: experiment 1: (a) 30·0%; (b) 28·6% and (c) 62·3% (P < 0·05); experiment 2: (a) 60·2%; (b) 57·8% and (c) 45·5% (P < 0·05). It is concluded that in heifers and non-suckling cows, oestrous synchronization treatments result in higher pregnancy rates. In non-suckling cows, the addition of a progestagen did not improve the response.

scholarly journals Influence of seasonality, timing of insemination and rectal temperature on conception rate of crossbred dairy cows

2016 ◽  
Vol 37 (1) ◽  
pp. 155 ◽  
Author(s):  
Fransérgio Rocha de Souza ◽  
Carla Cristian Campos ◽  
Natascha Almeida Marques da Silva ◽  
Ricarda Maria dos Santos
Keyword(s):  
Dairy Cows ◽  
Rectal Temperature ◽  
Artificial Insemination ◽  
Dairy Farm ◽  
Fixed Time ◽  
Conception Rate ◽  
Digital Thermometer ◽  
Pregnancy Diagnosis ◽  
Chi Squared

This study aimed to evaluate the effects of rectal temperature (RT) on conception rate (CR), as well as the effects of seasonality (spring-summer vs. autumn-winter) and timing of artificial insemination (AI) (morning vs. afternoon) on RT and CR in crossbred dairy cows (Holstein x Gyr). The experiment was conducted on a dairy farm in Centralina, MG, where 1,219 conventional and fixed-time inseminations were analyzed. The RT was measured immediately before AI using a digital thermometer. Pregnancy diagnosis was performed using ultrasonography between 28 and 60 days after AI. T The effects of seasonality and timing of AI on RT were analyzed with a Mann-Whitney U test and the effects of RT (above or below the average), seasonality and timing of AI on CR were analyzed with a Chi-squared test, both using the SAS program. The RT average was 39.4°C. Cows with RT ? 39.4°C had lower CR than cows with RT < 39.4°C (25.78% vs. 32.54%; P = 0.0096). During spring-summer, cows had higher RT (39.44°C ± 0.025 vs. 39.27°C ± 0.022; P < 0.0001) and lower CR (25.49% vs. 31.75%; P = 0.0146) compared with autumn-winter. Cows inseminated in the morning had lower RT (38.96°C ± 0.022 vs. 39.60°C ± 0.018; P < 0.0001) and higher CR (32.86% vs. 26.06%; P = 0.0102) than cows inseminated in the afternoon. In conclusion, crossbred dairy cows with rectal temperature equal to or greater than 39.4°C had lower conception rate. Moreover, rectal temperature and conception rate were affected by seasonality and insemination time.

068 Utilization of resynchronization as a strategy to increase the percentage of replacement beef heifers conceiving to artificial insemination (AI) after an initial fixed-time AI (TAI)

2016 ◽  
Vol 94 (suppl_1) ◽  
pp. 34-34
Author(s):  
P. L. P. Fontes ◽  
N. Oosthuizen ◽  
V. R. G. Mercadante ◽  
G. V. de Moraes ◽  
D. D. Henry ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Fixed Time ◽  
Beef Heifers

109 Pre-synchronization and reutilization of progesterone devices during a 6-day CO-Synch protocol for fixed-time artificial insemination in beef heifers

2021 ◽  
Vol 33 (2) ◽  
pp. 161
Author(s):  
E. R. Canadas ◽  
B. J. Duran ◽  
G. Machado ◽  
A. Nall ◽  
S. E. Battista ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Mixed Models ◽  
Generalized Linear Mixed Models ◽  
Fixed Time ◽  
P Value ◽  
Beef Heifers ◽  
Follicle Diameter ◽  
Follicle Size ◽  
Gonadotrophin Releasing Hormone ◽  
Intravaginal Device

Ovulatory response to the initial gonadotrophin-releasing hormone (GnRH) of the CO-Synch protocol is affected by circulating progesterone (P4) and follicle size. In addition, heifers that ovulate to the initial GnRH treatment have greater fertility after AI. Thus, this study determined the effect of (1) presynchronization (Presynch) before a 6-day CO-Synch protocol and (2) circulating [RCE1] (P4) on ovulatory response, oestrus expression, and pregnancies per AI (P/AI) in beef heifers. Yearling beef heifers (n=233) at three locations were randomly assigned in a 2×2 factorial design to the following treatments: (1) Presynch+6-day CO-Synch with a new P4 device; (2) Presynch+6-day CO-Synch with a once-used P4 device; (3) 6-day CO-Synch with a new P4 device; and (4) 6-day CO-Synch with a once-used P4 device. Presynch consisted of insertion of a new P4 intravaginal device (1.38g of P4) on Day −17 and removal of P4 device on Day −11 concurrently with 500µg of cloprostenol sodium (PGF). On Day −9, all heifers received either a new (New) or once-used (Used) CIDR and 100µg of gonadorelin acetate (GnRH). Six days later (Day −3), CIDRs were removed, 1000µg of PGF was administered and an oestrous detection patch applied (Estrotect). At 72h after CIDR removal, AI was performed concurrently with administration of 100µg of GnRH. Pregnancy was determined by transrectal ultrasonography 31 days after AI. A subset of heifers (n=155) was examined on Day −9 and Day −3 by ultrasonography to determine ovulation to Day −9 GnRH. Data were analysed using generalized linear mixed models (SAS 9.4; SAS Institute Inc.). Presynch heifers had larger follicle diameter on Day −9 (12.7±0.3 vs. 10.1±0.3 mm; P&lt;0.001), greater ovulatory response to Day −9 GnRH (82.5%; 66/80 vs. 56%; 42/75; P&lt;0.001), greater expression of oestrus (90.6%; 106/117 vs. 78.4%; 91/116; P&lt;0.02), and earlier oestrus (49.8±1 vs. 53.1±1 h; P&lt;0.01) compared with controls. There was a treatment×CIDR interaction on oestrous expression, such that a lesser (P&lt;0.05) percentage of control heifers with new CIDR expressed oestrus compared with all other groups (Table 1). Heifers with a used CIDR during the 6-day CO-Synch tended (P=0.08) to have greater P/AI (52.1%; 61/117) than those with a new CIDR (40.5%; 47/116). In conclusion, presynchronization before initiation of a 6-day CO-Synch increased follicle diameter, enhanced ovulatory response and oestrous expression, but did not affect fertility. The earlier onset of oestrus in presynchronized heifers suggests that the timing of AI may need to be modified. Table 1. Oestrous expression and pregnancy per AI (P/AI) in beef heifers with or without presynchronization and treated with a new or used CIDR during a 6-day CO-Synch Treatment CIDR Oestrus (%; n/n) Time of oestrus (h) P/AI (%; n/n) Control New 67.8a (40/59) 53.7±1.5a 33.9 (20/59) Used 89.5b (51/57) 52.7±1.6a 50.9 (29/57) Presynch New 94.7b (54/57) 50.9±1.4b 47.4 (27/57) Used 86.7b (52/60) 48.7±1.3b 53.3 (32/60) P-value Treatment 0.03 0.01 0.21 CIDR 0.62 0.19 0.08 Interaction 0.003 0.75 0.38 a,bValues with different superscripts differ (P&lt;0.05).

Effects of presynchronization and eCG on pregnancy rates to GnRH-based, fixed-time artificial insemination in beef heifers

2010 ◽  
Vol 90 (1) ◽  
pp. 23-34 ◽  
Author(s):  
J A Small ◽  
M G Colazo ◽  
J P Kastelic ◽  
N E Erickson ◽  
R J Mapletoft
Keyword(s):  
Chorionic Gonadotropin ◽  
Artificial Insemination ◽  
Follicular Development ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Preovulatory Follicle ◽  
Beef Heifers ◽  
Plasma Progesterone ◽  
Follicle Diameter ◽  
Equine Chorionic Gonadotropin

Three experiments were conducted to determine the effects of presynchronization and treatment with equine chorionic gonadotropin (eCG) on corpus luteum (CL) and ovarian follicular development, plasma progesterone concentrations, and pregnancy rates in beef heifers subjected to a gonadotropin releasing hormone (GnRH)-based, fixed-timed AI (TAI) protocol. All heifers were given GnRH on day 0, prostaglandin F2α (PGF) on day 7, and a second GnRH on day 9 concurrent with TAI (54 h after PGF). In exp. 1 (N = 148), presynchronization with PGF (days -22 and -11) decreased the percentage of heifers with non-luteal plasma progesterone concentrations on day 0 (5.4 vs 29.7%) and day 7 (0 vs 11.6%; P < 0.05), but not on day 9 (74.3 vs. 66.2%; P > 0.20), and reduced the number of heifers in estrus and bred before TAI (P < 0.05). Although presynchronization reduced preovulatory follicle diameter (12.9 ± 0.3 vs. 14.9 ± 0.3 mm; mean ± SEM; P < 0.01), it did not affect TAI pregnancy rates (36.5 vs. 29.7%; P > 0.20). In exp. 2, heifers (N = 128) were presynchronized with melengestrol acetate (MGA) (days -27 to -12), and received a controlled internal drug release (CIDR) on day 0; on day 7, half were given 300 IU of eCG at CIDR removal. Treatment with eCG tended to increase preovulatory follicle diameter in heifers that did not ovulate to GnRH on day 0 (P = 0.06), but did not affect the percentage of heifers with non-luteal plasma progesterone concentrations on day 9 (57.8 vs. 57.8%) or TAI pregnancy rates (48.4 vs. 53.1%; P > 0.20). Experiment 3 was a 2 × 2 factorial arrangement of presynchronization (PGF concurrent with a CIDR on day -7) and eCG treatments (on day 7) applied to heifers in three herds (A, N = 150, B, N = 260 and C, N = 40). All heifers had a once-used CIDR from days 0 to 7. Presynchronization increased the percentage of heifers (Herd A) with low-luteal plasma progesterone concentrations on day 0 (70.7 vs. 22.7%) and day 7 (90.7 vs. 53.3%; P < 0.01), but did not affect the percentage of heifers with non-luteal concentrations of progesterone on day 9 (97.3 vs. 93.3%; P > 0.20). Combined for all herds, presynchronization reduced the prevalence of a CL on day 0 (23.5 vs. 73.7%; P < 0.01), and increased the prevalence of follicles ≥ 10 mm on day 7 (96.8 vs. 86.7%; P < 0.01); however, TAI pregnancy rates (195/439 = 44.4%) were not improved by either presynchronization or eCG treatment (P > 0.20).Key words: Presynchronization, equine chorionic gonadotropin, GnRH, fixed-time artificial insemination, progesterone

scholarly journals PSXIII-12 Evaluation of split-time artificial insemination following administration of the 7-d CO-Synch + CIDR® estrus synchronization protocol in beef heifers

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 374-374
Author(s):  
Emma R Knickmeyer ◽  
Jordan M Thomas ◽  
James William C Locke ◽  
Rachael C Bonacker ◽  
Mark R Ellersieck ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Reproductive Tract ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Estrus Synchronization ◽  
Beef Heifers ◽  
Estrus Detection ◽  
Delayed Time ◽  
Split Time ◽  
Synchronization Protocol

Abstract Estrous response and pregnancy rates resulting from fixed-time (FTAI) or split-time (STAI) artificial insemination were compared among heifers following treatment with the 7-d CO-Synch + CIDR® (controlled internal drug release;1.38g progesterone) protocol. Heifers (n = 456) were assigned to balanced treatments based on weight and reproductive tract score (RTS; Scale 1–5). Gonadotropin-releasing hormone (GnRH; 100 µg gonadorelin acetate) was administered coincident with CIDR® insertion. Progesterone inserts were removed after 7 d, and PG (250 mg im cloprostenol sodium) was administered at CIDR® removal. Estrus detection aids (Estrotect®) were applied at the time PG was administered. Estrous status was recorded at FTAI or STAI, and estrus was defined as removal of ≥ 50% of the grey coating from the Estrotect® patch. Heifers assigned to the FTAI treatment received GnRH and were artificially inseminated 54 h after PG administration. In the STAI treatment, only heifers that expressed estrus prior to 54 h were artificially inseminated at that time. For heifers failing to express estrus, AI was postponed 24 h and only those heifers that failed to exhibit estrus by the delayed time (78 h) received GnRH concurrent with AI. Estrous response prior to the standard time of FTAI did not differ between treatments (P = 0.3). Total estrous response was increased (P &lt; 0.001) among heifers assigned to STAI (74%, STAI; 47%, FTAI); however, pregnancy rates resulting from AI were similar between treatments (48%, STAI; 46%, FTAI; P = 0.4), as were pregnancy rates at the end of a 60 d breeding season (P = 0.6). In summary, STAI resulted in a greater estrous response following treatment with the 7-d CO-Synch + CIDR® protocol; however, this did not result in an increase in pregnancy rate compared to heifers that received FTAI.

118 A comparison of intravaginal progesterone devices for fixed-time artificial insemination in beef cattle

2021 ◽  
Vol 33 (2) ◽  
pp. 167
Author(s):  
E. M. Zwiefelhofer ◽  
S. X. Yang ◽  
M. Asai-Coakwell ◽  
M. G. Colazo ◽  
J. Hellquist ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Animal Health ◽  
Colour Change ◽  
Fixed Time ◽  
Device Removal ◽  
Beef Heifers ◽  
Lactating Cows ◽  
Pregnancy Status ◽  
Gonadotrophin Releasing Hormone ◽  
Follicular Dynamics

Intravaginal progesterone (P4) devices used for ovarian synchronization before fixed-time AI (FTAI) differ in drug release, which may influence fertility outcome. A 2×2 study was designed to determine the effects of different intravaginal devices (PRID Delta, 1.55g of P4 vs. CIDR, 1.38g of P4) and parity (heifers vs. cows) on follicular dynamics, expression of oestrus, and pregnancy per AI (P/AI). At random stages of the oestrous cycle, nulliparous beef heifers and lactating cows were given 100µg of gonadorelin (gonadotrophin-releasing hormone, GnRH) intramuscularly (IM) and assigned randomly to either the PRID (n=76 heifers, 76 multiparous, 27 primiparous) or CIDR (n=76 heifers, 73 multiparous, 32 primiparous) group. Devices were removed 5 days later, an oestrus-detection patch was applied just cranial to the tail head, and 500µg of cloprostenol was given IM at the time of device removal and again 24h later. At 72h after device removal, cattle were inseminated and given 100µg of GnRH IM. Transrectal ultrasonography was used to determine the diameter of the largest follicle on the day of device removal and at FTAI, ovulation time, and pregnancy status 30 days after FTAI. A colour change of ≥50% of the oestrus-detection patch at FTAI was taken as expression of oestrus. Data were compared among groups by 2-way ANOVA using MIXED and GLIMMIX procedures. There were no interactions between P4 device and parity for any endpoint. The diameter of the largest follicle (mean±s.e.m.) was not different between PRID and CIDR groups on either the day of device removal (10.6±0.1 vs. 10.9±0.1mm) or the day of FTAI (13.7±0.1 vs. 13.9±0.1mm). The proportion displaying oestrus did not differ between P4 device groups, but was greater in heifers than in cows [121/152 (79.6%) vs. 135/207 (65.2%); P&lt;0.01], and the interval from FTAI to ovulation was shorter in heifers than in cows (27.8±1.2 vs. 32.0±1.1 h; P=0.01). The P/AI was not different between P4 device groups or parity groups (overall 67.0%, 238/355). However, among lactating cows, the P/AI tended to be greater in the PRID vs. CIDR group [75/102 (73.5%) vs. 64/105 (61.0%); P=0.10], and was greater in multiparous vs. primiparous cows [106/148 (71.6%) vs. 33/59 (55.9%); P=0.04]. Among cattle that displayed oestrus, the P/AI tended to be greater in the PRID vs. CIDR group [92/123 (74.8%) vs. 85/131 (64.9%); P=0.09]. Among lactating cows that displayed oestrus, the P/AI was greater in multiparous vs. primiparous cows [74/94 (78.2%) vs. 24/42 (57.1%); P&lt;0.01]. In summary, follicular dynamics and expression of oestrus did not differ between PRID and CIDR groups, but the P/AI tended to be greater in PRID-treated lactating cows and in cattle that displayed oestrus. This research was supported by CEVA Animal Health, Saskatchewan ADF, Agriculture and Agri-Foods Canada, and Rockway Inc.

Sign in / Sign up

Export Citation Format

Share Document