Follicular wave emergence, luteal function and synchrony of ovulation following GnRH or estradiol benzoate in a CIDR-treated, lactating Holstein cows

Self Cite

Abstract. This study compared two types of controlled internal drug release (CIDR)-based timed artificial insemination (TAI) protocol for treatment of repeat breeder dairy cows. In the first trial of the experiment, 55 repeat breeder cows were randomly assigned to the following two treatments. (1) In the EB group, a CIDR device was inserted into the cows, and then the cows were administered an injection of 1 mg estradiol benzoate (EB) plus 50 mg progesterone (P4; Day 0). On Day 7, they were given an injection of PGF2α and the CIDR device was removed. The cows were given an injection of 1 mg EB on Day 8 and were subjected to TAI 30 h later (n=27). (2) In the gonadotrophin releasing hormone (GnRH) group, a CIDR device was inserted into the cows, and then the cows were administered an injection of 250 µg gonadorelin (GnRH; Day 0). On Day 7, they were given an injection of PGF2α and the CIDR device was removed. The cows were given an injection of 250 µg GnRH on Day 9 and were subjected to TAI 17 h later (n=28). In the second trial, 41 repeat breeder cows that were confirmed as not pregnant in the first trial were randomly assigned to the same two treatments used in the first trial (an EB group of 20 cows and a GnRH group of 21 cows). The ovaries of 15 cows from each group were examined by transrectal ultrasonography in order to observe the changes in ovarian structures, and blood samples were collected for analysis of serum P4 concentrations. The pregnancy rates following TAI in the first (18.5 vs. 32.1%) and second (40.0 vs. 38.1%) trials and the combined rates (27.7 vs. 34.7%) did not differ between the EB and GnRH groups. The proportions of cows with follicular wave emergence within 7 days did not differ between the EB (12/15) and GnRH groups (13/15). The interval to wave emergence was shorter (P<0.01) in the GnRH group than in the EB group, but there was no difference in the mean diameters of dominant follicles on Day 7 between the groups. Moreover, the proportions of cows with synchronized ovulation following a second EB or GnRH treatment did not differ between the groups. In conclusion, treatment with either EB or GnRH in a CIDR-based TAI protocol results in synchronous follicular wave emergence, follicular development, synchronous ovulation, and similar pregnancy rates for TAI in repeat breeder cows. Key words: Controlled internal drug release (CIDR), Estradiol benzoate, Gonadotrophin releasing hormone (GnRH), Pregnancy rate, Repeat breeder dairy cows (J. Reprod. Dev. 53: [639][640][641][642][643][644][645] 2007) ncreased milk production in dairy cows induced by continuous genetic manipulation, improved nutritional management, and larger herd size is associated with decreased fertility [1][2][3].

Section: Discussioncontrasting

confidence: 83%

Section: Discussioncontrasting

confidence: 70%

Comparison of Two Types of CIDR-based Timed Artificial Insemination Protocols for Repeat Breeder Dairy Cows

Kim

Suh

Hur

et al. 2007

Self Cite

“…On the other hand, the ranges of the intervals to follicular wave emergence varied in the T1 (3 to 8 days) and T2 groups (3 to 6 days) and were consistent with the previously reported range of 2 to 7 days obtained using 2 mg EB [21] or 4 mg EB [2]; however, they were different from the ranges of 3 to 4 days observed using 2.5 mg EB plus 50 mg P4 [11] or 5 mg E 2 plus 100 mg P4 [9] and 3 to 5 days with 5 mg E 2 [22]. Variations in the interval to wave e m e r g e n c e d e p e n d o n b o t h t h e e s t r a d i o l preparation and dose.…”

Section: Discussionsupporting

confidence: 91%

“…nduction of precise synchronization of follicular wave emergence, irrespective of the estrous cycle at the time of treatment, is important for successfully timed artificial insemination (TAI) [1,2] and superovulatory treatment [3,4] in cattle. To date, the protocols to induce precise synchrony o f o v u l a t i o n w i t h n o r m a l f e r t i l i t y h a v e concentrated on producing a homogenous population of follicles with a short duration of dominance (<10 days) at the onset of proestrus [5].…”

mentioning

confidence: 99%

The Effects of Administering Estradiol Benzoate Plus Progesterone During the Growth or Static Phases of the Dominant Follicle in CIDR-Treated Lactating Dairy Cows

Kim

Suh

Hur

et al. 2007

Self Cite

Abstract.We studied the effects of administering estradiol benzoate (EB) plus progesterone (P4) as part of a CIDR-based protocol during the growth or static phases of dominant follicle development on follicular wave emergence, follicular growth, synchrony of ovulation and pregnancy rate following CIDR withdrawal, treatment with PGF2α and GnRH, and fixed-time artificial insemination (TAI). Forty-one previously synchronized lactating Holstein dairy cows were randomly allocated to three treatment groups. The control group (n=14) received a CIDR on the third day after ovulation only (Day 0). The two treatment groups were administered CIDRs comprising 2 mg EB and 50 mg P4 either on the third (T1, n=14) or eighth day (T2, n=13) after ovulation (Day 0). All cows received PGF2α after CIDR removal on Day 7, GnRH on Day 9, and TAI 16 h after GnRH treatment. The proportion of cows with follicular wave emergence within 8 days of treatment differed (P<0.01) among the control (14.3%), T1 (85.7%), and T2 groups (92.9%). However, the mean intervals between treatment and wave emergence were not significantly different. There were significant differences in the diameters of the dominant follicles on Day 7 (P<0.01) and in preovulatory follicles on Day 9 (P<0.01), with the largest follicles observed in the control group and the smallest follicles observed in the T2 group. In contrast, the numbers of cows showing synchronous ovulation after GnRH treatment (92.9 to 100.0%) and pregnancy following TAI (46.2 to 50.0%) were similar between the treatment groups. The results showed that, irrespective of the phase (growth or static) of the dominant follicle, administration of 2 mg EB plus 50 mg P4 to CIDR-treated lactating dairy cows induced consistent follicular wave emergence and development, synchronous ovulation after GnRH administration, and similar pregnancy rates following TAI.

“…Yavas et al [4] demonstrated that insertion of a progesterone-releasing intravaginal devise (PRID) for 10 days into the vagina of 21-day postpartum beef cows allowed the dominant follicle to undergo terminal maturation; an LH surge; ovulation; a normal lifespan and function for the CL; and continued cyclicity in 50 to 60% of the cows. Use of an intravaginal progesterone-releasing device in protocols for ovulation synchronization and timed artificial insemination (TAI) has been reported to be effective for increasing conception rate [5][6][7][8][9][10][11][12][13]. Application of this protocol (PRID + TAI) could shorten the calving interval and have notable economic effects.…”

mentioning

confidence: 99%

Applicability of a Progesterone-Based Timed Artificilal Insemination Protocol after Follicular Fluid Aspiration Using the Ovum Pick-up Technique in Suckled Beef Cows

Hirata

Hoshina

Sasaki

et al. 2007

Abstract. We conducted a progesterone-based timed AI protocol after follicular fluid aspiration using the ovum pick-up (OPU) technique to examine its applicability to the suckled beef cow. A total of 19 beef cows were randomly allocated to one of the following three groups based on the number of days postpartum: 13 to 60 days (Group A: suckled; early postpartum period, n=9), 61 to 150 days (Group B: suckled; mid postpartum period, n=6), or 151 to 281 days (Group C: non-suckled; prolonged open period, n=4) postpartum. These cows were treated with follicular fluid aspiration and insertion of a progesterone-releasing intravaginal device (PRID) on day 0. The PRID was removed and 500 µg of cloprostenol was intramuscularly administered on day 7. A dose (100 µg) of fertirelin acetate was injected intramuscularly 48 hours later, and this was followed by a timed AI (TAI) after another 18 hours (day 10). Serum samples were taken on days 0, 7, 9, 10, 12, 17, 24 and 31 for determination of the estradiol-17β (E2) and progesterone concentrations. Pregnancy diagnosis was made by rectal palpation approximately 60 days after TAI. There was no significant difference in the peripheral E2 concentrations among the three groups during the period of the hormonal treatment. The average progesterone concentrations in Group A on day 17 were significantly higher than those in Group B and exceeded 1.0 ng/ml on day 17 and thereafter. There was no significant difference in the numbers of collected immature oocytes among the three groups. The pregnancy rates in Groups A, B, and C were 77.8% (7/9), 83.3% (5/6) and 50.0% (2/4), respectively. In conclusion, this timed AI protocol is applicable to suckled beef cows within the period of 60 days postpartum.