Effect of 1 or 2 norgestomet implants inserted from days 15 to 25 after oestrus on follicular development in beef cows

Controlling the timing of ovulation in cows that fail to conceive after insemination would provide a further opportunity for scheduled rebreeding in a group of cows to save time and optimise results. The ear implant Crestar containing the synthetic progestagen norgestomet provides a means of achieving this control (Sinclair et al., 1992; Lowman et al., 1994). Removing the implant on day 25 after oestrus results in less false positive pregnancy diagnoses than removal on day 21 with the implant in place for nine/ten days. However, treatment of beef heifers with a norgestomet implant towards the end of luteal phase to control oestrus and ovulation is associated with development of a persistent ovulatory follicle and reduced pregnancy rate (Mihm et al., 1994). The objective of this study was to determine the effects of treating beef cows with one or two norgestomet implants on the development of the dominant ovulatory follicle of the second follicular wave.

Effect of 1 or 2 norgestomet implants inserted from days 15 to 25 after oestrus on follicular development in beef cows

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200593296 ◽

1996 ◽

Vol 1996 ◽

pp. 133-133

Author(s):

D.A. Adikpe ◽

M.J. Bryant

Keyword(s):

Pregnancy Rate ◽

False Positive ◽

Luteal Phase ◽

Follicular Development ◽

Beef Cows ◽

Beef Heifers ◽

Follicular Wave ◽

Progesterone as the driving regulatory force behind serum FSH concentrations and antral follicular development in cycling ewes

10.1071/rd10121 ◽

2011 ◽

Vol 23 (2) ◽

pp. 303 ◽

Cited By ~ 14

Author(s):

Tanya E. Baby ◽

Pawel M. Bartlewski

Keyword(s):

Luteal Phase ◽

Follicular Development ◽

Treated Group ◽

Time Frame ◽

Oestrous Cycle ◽

Control Group ◽

Corpora Lutea ◽

Follicular Waves ◽

Follicular Wave ◽

And Control

Ovarian antral follicles in sheep grow in an orderly succession, producing typically three to four follicular waves per 17-day oestrous cycle. Each wave is preceded by a transient increase in circulating FSH concentrations. The mechanism controlling the number of recurrent FSH peaks and emerging follicular waves remains unknown. During the ewe’s oestrous cycle, the time between the first two FSH peaks and days of wave emergence is longer than the intervals separating the ensuing FSH peaks and follicular waves. The prolonged interpeak and interwave interval occurs early in the luteal phase when low levels of progesterone are secreted by developing, or not fully functional, corpora lutea (CL). The purpose of the present study was to determine the effect of varying progesterone (P4) levels on circulating concentrations of FSH and antral follicular development in sheep. Exogenous P4 (15 mg per ewe, i.m.) was administered twice daily to six cycling Rideau Arcott × Dorset ewes from Day 0 (ovulation) to Day 4 (the mean duration of the interwave interval); six animals served as controls. Follicular growth was monitored in all animals by daily transrectal ultrasonography (Days 0–9). Jugular blood samples were drawn twice a day from Day 0 to Day 4 and then daily until Day 9 to measure systemic concentrations of P4, FSH and 17β-oestradiol (E2). The first FSH peak after ovulation was detected on Days 1.5 ± 0.2 and 4.2 ± 0.2 in treated and control ewes, respectively (P < 0.05). The next FSH peak(s) occurred on Day 3.9 ± 0.3 in the treated group and on Day 6.4 ± 0.5 in the control group. Consequently, the treated group had, on average, three follicular waves emerging on Days 0, 3 and 6, whereas the control group had two waves emerging on Days 0 and 5. Mean serum E2 concentrations were greater (P < 0.05) in control compared with treated ewes on Days 1.3, 2.3, 3.3, 4.0 and 4.3 after ovulation. In summary, creation of mid-luteal phase levels of P4 in metoestrus shortened the time to the first post-ovulatory FSH peak in ewes, resulting in the emergence of one more follicular wave compared with control ewes during the same time frame. Therefore, P4 appears to be a key endocrine signal governing the control of periodic increases in serum FSH concentrations and the number of follicular waves in cycling sheep.

Association between the duration of dominance of the ovulatory follicle and pregnancy rate in beef heifers

Reproduction ◽

10.1530/jrf.0.1020123 ◽

1994 ◽

Vol 102 (1) ◽

pp. 123-130 ◽

Cited By ~ 179

Author(s):

M. Mihm ◽

A. Baguisi ◽

M. P. Boland ◽

J. F. Roche

Keyword(s):

Pregnancy Rate ◽

Beef Heifers ◽

Effect of the ovulatory follicle diameter and progesterone concentration on the pregnancy rate of fixed-time inseminated lactating beef cows

Revista Brasileira de Zootecnia ◽

10.1590/s1516-35982012000400024 ◽

2012 ◽

Vol 41 (4) ◽

pp. 1004-1008 ◽

Cited By ~ 9

Author(s):

Luiz Francisco Machado Pfeifer ◽

Sofia del Carmen Bonilla de Souza Leal ◽

Augusto Schneider ◽

Eduardo Schmitt ◽

Marcio Nunes Corrêa

Keyword(s):

Pregnancy Rate ◽

Fixed Time ◽

Beef Cows ◽

Progesterone Concentration ◽

Follicle Diameter ◽

18 STRATEGIES TO IMPROVE FERTILITY WITH COSYNCH-CIDR PROTOCOLS IN BEEF CATTLE

10.1071/rdv17n2ab18 ◽

2005 ◽

Vol 17 (2) ◽

pp. 159 ◽

Cited By ~ 2

Author(s):

R. Mapletoft ◽

M. Colazo ◽

L. Siqueira ◽

J. Small ◽

M. Rutledge ◽

...

Keyword(s):

Pregnancy Rate ◽

Animal Health ◽

Beef Cows ◽

Preovulatory Follicle ◽

Beef Heifers ◽

Treatment Control ◽

Pfizer Animal Health ◽

Follicle Size ◽

D 12 ◽

To Receive

Two experiments were designed to evaluate strategies to improve fertility with Cosynch-CIDR protocols in cattle. The first experiment investigated the effect of low levels of progesterone prior to a Cosynch-CIDR protocol. On Day 0, lactating beef cows (n = 34) and heifers (n = 37) were placed in two groups to receive 500 μg cloprostenol (PGF; Estrumate, Schering-Plough Animal Health, Pointe-Claire, Quebec, Canada) or a twice-used CIDR (Bioniche Animal Health, Belleville, Ontario, Canada) for 5 days (Pretreatment) or no treatment (Control). On Day 5, used CIDRs were removed and all cattle received a new CIDR (Pfizer Animal Health, Montreal, Quebec, Canada) and 100 μg GnRH (Cystorelin, Merial Canada Inc, Victoriaville, Quebec, Canada). On Day 12, CIDR were removed and PGF was given. A second GnRH was given concurrent with timed AI (TAI) on Day 14 (54–56 h after PGF). Cattle were examined by transrectal ultrasonography for CL and follicle development, and for confirmation of pregnancy (Days 42 to 49). Diameter of the dominant follicle on Day 5 was larger and more variable in cows than in heifers (15.5 ± 5.6 vs. 11.4 ± 3.5 mm, respectively; means, P < 0.001; variance, P < 0.003), and tended to be larger in the Pretreatment group (14.3 ± 4.9 vs. 12.6 ± 5.2 mm; P = 0.13). More Pretreated (60.0%) than Control (36.1%) cattle (P < 0.005), and more cows (64.7%) than heifers (32.4%; P < 0.03) ovulated following the first GnRH. At the time of TAI, 5 (13.5%) heifers had already ovulated (P < 0.03). Diameter of the preovulatory follicle was affected by parity (P < 0.001), but not Pretreatment (P = 0.4), and tended to be larger in heifers that became pregnant (P = 0.13). Pregnancy rate was not affected by parity (P = 0.71), or pretreatment (P = 0.34); pretreatment tended to increase pregnancy rate in heifers (63.2 vs. 38.9%; P = 0.19). The second experiment evaluated the use of eCG in a Cosynch-CIDR protocol in beef heifers. Beef heifers (n = 127) were fed 0.5 mg/head/day of MGA (Pfizer Animal Health) for 15 d; 12 d after the last feeding (designated as Day 0) heifers received a CIDR and 100 μg GnRH. On Day 7, CIDR were removed, and heifers received PGF, and were randomly placed in 2 groups to receive 300 IU of eCG (Pregnacol; Bioniche Animal Health) or no treatment (Control). On Day 9 (54–56 h after PGF), all heifers received 100 μg GnRH, concurrent with TAI. Ultrasonographic examinations were done as in the first experiment. Overall, 79.5% of the heifers had a CL, and 9.4% had a luteinized follicle on Day 0. Seventy-eight heifers (61.4%) ovulated following the first GnRH, and those that ovulated had a less variable preovulatory follicle size than those that did not (13.7 ± 1.7 vs. 13.8 ± 2.3 mm; means, P = 0.76; variance, P < 0.01). However, there was no difference in preovulatory follicle size (P = 0.63), or pregnancy rate (49.2 vs. 53.1%; P = 0.7) for eCG-treated vs. Control heifers. In summary, pretreatment with a twice-used CIDR plus PGF increased the proportion of cattle that ovulated to the first GnRH, but not preovulatory follicle size or fertility in cows; fertility tended to be improved in heifers. Treatment with eCG did not increase preovulatory follicle size or fertility in heifers subjected to an Cosynch-CIDR protocol.

11 EFFECTS OF CIDR-BASED PRESYNCHRONIZATION AND eCG ON FERTILITY FOR A GnRH-BASED TIMED-AI PROTOCOL IN BEEF CATTLE

10.1071/rdv18n2ab11 ◽

2006 ◽

Vol 18 (2) ◽

pp. 114 ◽

Cited By ~ 2

Author(s):

M. Colazo ◽

J. Small ◽

J. Kastelic ◽

H. Davis ◽

D. Ward ◽

...

Keyword(s):

Beef Cattle ◽

Factorial Design ◽

Pregnancy Rate ◽

Animal Health ◽

Beef Cows ◽

Beef Heifers ◽

Treatment Control ◽

Pfizer Animal Health ◽

Exogenous Progesterone ◽

To Receive

The objectives were to determine the effects of presynchronization and eCG on fertility for a GnRH-based timed-AI (TAI) protocol in beef cattle. Previously autoclaved once-used CIDR inserts (Colazo et al. 2004 Anim. Reprod. Sci. 81, 25-34) were used for experimental purposes so that all cattle had equivalent exogenous progesterone after Day 7 in Experiment 1, and to induce GnRH-responsive follicles in Experiment 2. In Experiment 1, 12-15 month old beef heifers (n = 447) were used (three locations, A, B, and C). On Day 0, half received a new CIDR insert (Pfizer Animal Health, Montreal, Quebec, Canada) and 500 �g of cloprostenol i.m. (PGF: Estrumate; Schering-Plough Animal Health, Pointe-Claire, Quebec, Canada). On Day 7, the remainder received an autoclaved once-used CIDR and all received 100 �g of GnRH i.m. (Cystorelin; Merial Canada, Inc., Victoriaville, Quebec, Canada). On Day 14, CIDR inserts were removed, PGF was given to all heifers, and heifers were given either 300 IU eCG i.m. (Pregnacol; Bioniche Animal Health, Belleville, Ontario, Canada) or no treatment (2 � 2 factorial design). On Day 16 (54-56 h after CIDR removal and PGF administration), heifers were given 100 �g of GnRH i.m., concurrent with TAI. Transrectal ultrasonography was done on Day 0 to assess ovarian structures, and on approximately Day 50 (range, 44-69) to confirm pregnancy. Overall, 72.7% of heifers were puberal on Day 0 (150/150, 5/37, and 170/260 for locations A, B, and C, respectively; P < 0.001). Pregnancy rate was affected (P < 0.001) by location (27.3, 62.2, and 51.1% for the three locations, respectively) but was not affected (P = 0.3) by puberal status at locations B and C. Pregnancy rate was not affected (P = 0.5) by presynchronization, but tended (P = 0.1) to be reduced by eCG treatment (40.4 vs. 47.7%, respectively). In Experiment 2, lactating crossbred beef cows (n = 411), 2-12 years of age were randomly allocated to receive either a previously used, autoclaved CIDR for 7 days and 25 mg of dinoprost i.m. (PGF: Lutalyse; Pfizer Animal Health) or no treatment (control; Day 0). At CIDR removal (Day 7), all cows received 100 �g of GnRH. On Day 14, all cows received PGF and were allocated to receive either 400 IU of eCG i.m. or no treatment (2 � 2 factorial design). On Day 16 (54-56 h after PGF), cows were given 100 �g of GnRH concurrent with TAI. Transrectal ultrasonographic examinations were done on approximately 65 cows in each group on Days 0, 7, and 14 to assess ovarian structures and on all cows on Day 42 to confirm pregnancy. Overall, 88.8% of cows had a corpus luteum (CL) on Day 0. Presynchronization increased both the proportion of cows that ovulated to GnRH treatment on Day 7 (76.7 vs. 55.0%; P < 0.001) and pregnancy rate (58.2 vs. 45.4%; P = 0.03) for cows that had received a CIDR vs. control cows. However, eCG treatment did not affect pregnancy rate (P = 0.3) in either group. In summary, presynchronization with a used CIDR and PGF prior to a Cosynch protocol increased ovulation rate to the first GnRH treatment and pregnancy rate in cows but not in heifers. In a GnRH-based TAI protocol, treatment with eCG had no significant effect on fertility in cows, but tended to decrease fertility in heifers.

20 EFFECTS OF DOSE OF ESTRADIOL BENZOATE AND PROGESTERONE IN PROSTAGLANDIN-TREATED BEEF HEIFERS

10.1071/rdv17n2ab20 ◽

2005 ◽

Vol 17 (2) ◽

pp. 160

Author(s):

M. Martínez ◽

M. Caccia ◽

M. Colazo ◽

G. Bó ◽

J. Kastelic ◽

...

Keyword(s):

Animal Health ◽

Follicular Development ◽

Estradiol Benzoate ◽

Beef Heifers ◽

Once Daily ◽

Treatment Groups ◽

Dose Time ◽

Follicular Wave ◽

Time Interaction ◽

To Receive

Estradiol and progesterone have been used to synchronize follicular wave emergence and ovulation in a two-dose prostaglandin (PGF)-based synchronization program (Martínez et al. 2004 Theriogenology 62, 363–372). However, it was observed that some heifers displayed estrus prior to the second PGF, suggesting that premature luteolysis may have occurred. An experiment was designed to determine the effects of dose of estradiol benzoate (EB) and/or progesterone (P) on follicular and luteal dynamics in a two dose PGF-based protocol in beef heifers. In two replicates, beef heifers (n = 28; Simmental, Hereford, and Charolais crosses, 350 to 450 kg) received 500 μg cloprostenol (Schering-Plough Animal Health, Pointe-Claire, PQ, Canada) on Day −7. On Day 0, heifers were randomly allocated to nine treatment groups to receive 0, 1, or 2 mg of EB and 0, 50, or 100 mg of P i.m. in canola oil in a 3 × 3 factorial design. A second PGF treatment was administered on Day 14. Ultrasonography was done once daily from Days −5 to 9, and every 12 h thereafter until ovulation. Blood samples were collected at 12-hour intervals from Day 0 to 5 for estradiol and FSH concentrations, and every 24 h for progesterone. The effects of EB and P and their interaction on corpus luteum (CL), follicles, and hormone profiles were analyzed by analysis of variance, and means were compared by LSD or Tukey's test. All variables were normally distributed (Wilk-Shapiro test and rankit plots). The day of follicular wave at the time of treatment tended to vary among groups (P = 0.08) and the diameter of the dominant follicle also differed (P < 0.05). The interval from treatment to wave emergence was shorter (P < 0.05) in heifers that received 2 mg EB (4.6 ± 0.3 d) than in those that did not receive EB (5.9 ± 0.6 d), while the 1 mg EB group (5.1 ± 0.6 d) was intermediate. The interval to wave emergence in the 2 mg EB group was the least variable (P < 0.05). There was no effect of EB (P = 0.72) on the diameter of the CL at the time of the second PGF, but there was an effect of P treatment (P = 0.01). The variability of the interval from the second PGF to ovulation may have been influenced by treatment group but was statistically not significant (P < 0.1). There was an effect of time (P < 0.01) on plasma progesterone concentrations and a P × time interaction (P = 0.06) can also be assumed. Estradiol concentrations were affected by EB dose, time, and EB × time interaction (all P < 0.01). FSH concentrations were modified by time (P < 0.01). In summary, treatment with EB 7 days after a single injection of PGF affected follicular development, while P treatment at that time appeared to influence CL function.

Follicular waves and concentrations of steroids and inhibin A in ovarian venous blood during the luteal phase of the oestrous cycle in ewes with an ovarian autotransplant

Journal of Endocrinology ◽

10.1677/joe.0.1560563 ◽

1998 ◽

Vol 156 (3) ◽

pp. 563-572 ◽

Cited By ~ 34

Author(s):

CJ Souza ◽

BK Campbell ◽

DT Baird

Keyword(s):

Luteal Phase ◽

Venous Blood ◽

Follicular Development ◽

Inhibin A ◽

Ovarian Steroids ◽

Antral Follicles ◽

Follicular Wave ◽

Follicle Diameter ◽

Before And After ◽

Follicular Size

The dynamics of ovarian follicular development and the pattern of pituitary and ovarian hormone concentration were investigated during the luteal phase in ewes with autotransplanted ovaries. The follicles were measured by ultrasound and samples of ovarian and jugular venous blood were collected at intervals of 12 h. Blood samples were collected before and after a GnRH challenge (250 ng GnRH, i.v.) to allow the determination of basal and LH-stimulated concentration of ovarian steroids. Throughout the luteal phase, large antral follicles developed in three waves, each of which was preceded by a rise in the concentration of FSH (P < 0.05). The concentrations of oestradiol and androstenedione in the unstimulated and LH-stimulated samples were similar (P > 0.05) during the first 3 days of the luteal phase but differed thereafter, with the LH-stimulated being significantly higher than the basal concentrations (P < 0.05). In the first wave of follicular development the changes in follicular size were accompanied by an increase in the concentration of ovarian steroids and inhibin A. During the second follicular wave, although changes in follicle diameter were similar to the first wave (P > 0.05), the basal concentration of ovarian steroids and inhibin A remained unchanged throughout the period of emergence and demise of the large follicles. These results confirm that the development of large antral follicles during the luteal phase of the sheep occurs in successive waves that are associated with fluctuations in FSH secretion. However while the results strongly suggest that fluctuations in both inhibin A and oestradiol secretion control FSH during the first follicular wave, the cause of the FSH fluctuations associated with waves two and three is unclear. Final resolution of this issue may need to await the development of a specific assay for dimeric inhibin B.

Effect of injectable progesterone on follicular development in lactating beef cows treated with estradiol plus a low-concentration progesterone device

Brazilian Journal of Veterinary Research and Animal Science ◽

10.11606/issn.1678-4456.bjvras.2018.136924 ◽

2018 ◽

Vol 55 (2) ◽

pp. e136924

Author(s):

Luiz Francisco Machado Pfeifer ◽

Reuben John Mapletoft ◽

Dinesh Dardawal ◽

Jaswant Singh

Keyword(s):

Canola Oil ◽

Animal Health ◽

Follicular Development ◽

Beef Cows ◽

Estradiol Benzoate ◽

Crossover Design ◽

Dominant Follicle ◽

Device Removal ◽

Progesterone Concentration ◽

The effect of injectable progesterone was evaluated along with estradiol benzoate (EB) on the fate of the dominant follicle (DF) present in the ovary at the beginning of low progesterone-based TAI protocol. All cattle were given 500 µg cloprostenol im (PGF; Schering-Plough Animal Health for Estrumate, Pointe-Claire, QC, Canada) twice, 11 d apart, and allocated into two groups: Estradiol group (E group, n = 11) and Estradiol-Progesterone group (EP group, n = 11). Ten days after the second PGF (Day 0), all cattle were given an intravaginal progesterone device with half progesterone concentration (Cue-Mate with a single pod containing 0.78 g progesterone). Concurrently, all cattle were given 1.5 mg im of estradiol benzoate in 3 mL of canola oil and PGF im on Day 0 of the protocol in a crossover design, in which each cow received both treatments. Cows in the EP group also received 100 mg im progesterone (Sigma) in 2 mL of canola oil. On Day 8, progesterone devices were removed and all cattle were given PGF im. All statistical analyses were performed with SAS 9.0. The DF present on Day 0 ovulated in 76% (16/21) of cows from E group and 28.6% (6/21) of cows from EP group (P = 0.002). After progesterone device removal, the size of ovulatory follicle did not differ between groups (E group, 15.5 ± 0.43 mm vs EP group, 15.8 ± 0.98 mm; P = 0.82). These follicles ovulated in 81.3 ± 3.1 h in E group and 71.0 ± 6.1 h in EP group (P = 0.13). In conclusion, injectable progesterone reduced the proportion of cows that ovulate the dominant follicle present in the ovary at the beginning of estradiol-progesterone-based protocols. However, no difference was detected on time of ovulation after progesterone device removal between groups.

Progesterone administered after insemination did not affect the fertility of cattle following a controlled breeding program

Australian Journal of Experimental Agriculture ◽

10.1071/ea9900179 ◽

1990 ◽

Vol 30 (2) ◽

pp. 179 ◽

Cited By ~ 8

Author(s):

RK Munro ◽

J Bertram

Keyword(s):

Pregnancy Rate ◽

Luteal Phase ◽

Beef Cows ◽

Breeding Program ◽

Control Group ◽

Intravaginal Administration ◽

And Control ◽

Pregnant Mare Serum Gonadotrophin

Oestrus and ovulation were induced in 112 suckled beef cows following intravaginal administration of progesterone (CIDR-B) and pregnant mare serum gonadotrophin (PMSG). Supplementary progesterone was provided during the induced luteal phase by re-treatment with CIDR-B from 6-21 or 10-21 days after initial insemination. A control group did not receive supplementary progesterone Supplementary progesterone did not affect the pregnancy rate to the initial insemination (59%). It did, however, tend to increase the proportion of non pregnant cows detected in oestrus 21-24 days after the initial insemination (17131 v. 3/14, P<0.05), but the fertility of treated and control cows inseminated at this second oestrus was not significantly different (30%).