CIDR Device Research Articles

Comparison of two intravaginal progesterone-releasing devices in lactating Holstein cows synchronized with a 5-d GnRH-based timed-AI protocol

The objective of the study was to compare the effectiveness of CIDR vs. PRID-Delta devices for use in a 5-day Ovsynch protocol for TAI in lactating Holstein cows that were either not in estrus after the end of the voluntary waiting period or non-pregnant and not returning to estrus following the previous AI. Cows fitted with a collar-mounted automated activity monitoring system (Alta Cow Watch) were subjected to a standard 5-d Ovsynch protocol [100 μg of gonadorelin (GnRH) on Day 0 and 500 μg of cloprostenol on Days 5 and 6] and allocated randomly to receive either an intravaginal device containing 1.35 g (CIDR; n = 304) or 1.55 g (PRID ® DELTA; n = 304) of progesterone between Day 0 and 5. All cows received a second administration of GnRH at approximately 56 h and timed-AI (TAI) 72 h after intravaginal device removal. Inseminations were done using conventional frozen-thawed semen. Estrus events prior to TAI were recorded and transrectal ultrasonography was done on Day 0 to determine presence of a corpus luteum (CL) and 33 and 61 d post-TAI, respectively, to diagnose and confirm pregnancy. Cows had an average of 2.2 lactations, 124.3 days in milk, and a milk yield of 43.6 kg/d at enrollment. The overall percentage of cows with a CL at initiation of treatment was 68.8 % and did not differ between treatment groups. Cows with a CL had greater pregnancy per AI (P/AI) at 33 and 61 d post-TAI than cows without a CL (P < 0.01; 46.9 and 42.3 % vs. 32.1 and 27.4 %, respectively). The overall percentage of cows that expressed estrus prior to TAI was 24.8 % and did not differ between treatment groups; however, estrus expression prior to TAI affected P/AI at 33 and 61 d post-TAI (P < 0.01; 53.6 and 49.0 % vs. 38.5 and 33.9 % for those expressing or not expressing estrus, respectively). Pregnancy per AI at 33 d post-TAI tended to differ between treatment groups (P = 0.08; 46.1 vs. 38.5 % for PRID and CIDR groups, respectively) and P/AI at 61 d post-TAI was greater (P < 0.01) for PRID-treated cows (43.8 %) compared to CIDR-treated cows (31.6 %). Thus, PRID-treated cows had lower pregnancy loss than CIDR-treated cows (P < 0.01; 5.0 vs. 17.9 %). Also, treatment with a PRID tended (P = 0.08) to result in fewer twin pregnancies (7.9 vs. 14.5 % for PRID and CIDR treated cows, respectively). In conclusion, lactating dairy cows subjected to a 5-d Ovsynch TAI protocol plus a PRID-Delta had greater P/AI at 61 d post-TAI, lower pregnancy loss between 33 and 61 d post-TAI, and fewer twin pregnancies compared to cows subjected to a 5-d Ovsynch protocol plus a CIDR.

Efficacy of omitting initial GnRH in once-used CIDR co-synch protocol for the treatment of anestrus in buffaloes during low breeding season

Progesterone-based hormonal protocols are effective to treat anestrus in buffaloes. However, most of those protocols are costly, thus, requiring a cost-effective protocol that minimizes handling frequencies. This study, therefore, evaluated the effectiveness of the ‘once-used CIDR co-synch protocol’ with or without initial GnRH for treating anestrus in buffaloes during low breeding season. Anestrous buffaloes (n=29) were divided into two Treatment groups. As a part of the ‘once-used CIDR co-synch protocol,’ the first group (T1, n=18) received an initial GnRH on a random day (day 0) while the second group (T2, n=11) did not receive it. On day 0, the once-used CIDR device was inserted intravaginally in both groups, with GnRH administered in T1 but omitted in T2. On day 7, during CIDR removal, each buffalo received PGF2α, and on day 10, GnRH was given, and fixed-timed artificial insemination (FTAI) was done. Ovarian status was assessed on d0 and on 8 to 9-day post-FTAI using transrectal ultrasonography. Plasma progesterone concentrations on 8 to 9-day post-FTAI were determined using ELISA. No significant differences in estrus expression, ovulation and pregnancy rates were observed between two Treatment groups, with overall rates of 93%, 69%, and 34.5%, respectively. However, the overall pregnancy outcome (from FTAI plus natural breeding of buffaloes that returned to estrus) up to 2 months post-FTAI was 48.3%. Parity affected the ovulation among treated buffaloes, with higher (P=0.04) ovulation rate in buffaloes ≤4th parity (79.2%) compared to &gt;4th parity (20%). There were no differences in CL size and plasma progesterone concentrations during 8 to 9-day post-FTAI between two treatment groups. In conclusion, omitting the initial GnRH in ‘once-used CIDR Co-synch protocol’ proved equally effective as the protocol with initial GnRH for the treatment of anestrus in buffaloes during the low breeding season.

Ovarian response and conception rate in Boran and Boran*Holstein cows treated by Gonadotrophin-realizing hormone and ProstaglandinF2α with and without exogenous progesterone

BackgroundDifference in breed, nutrition status and climate in which animals are managed result in differences in response to reproductive hormones. Fertility rate to artificial insemination is very low in Ethiopian Boran and Boran*Holstein crosses. This partly maybe due to adopting estrus and/or ovulation synchronization developed for temperate taurine cattle. Experimental study was conducted to evaluate ovarian response to combinations of Gonadotrophin-Realizing Hormone agonist (gonadorelin) and ProstaglandinF2α (PGF2α) with or without progesterone (Controlled Internal Drug Release/CIDR), and conception rate to timed AI. Postpartum native Ethiopian Boran (n = 60) and Boran*Holstein cross (n = 66) cows were randomly assigned to four treatment groups as Ovsynch (gonadorelin on day of start, PGF2α seven days later, 2nd gonadorelin at 48 h of PGF2α and insemination at 19 h of the 2nd gonadorelin); CIDR + Ovsynch (same as Ovsynch but CIDR device was inserted into vagina for 7 days); Cosynch (same as Ovsynch but insemination was made at the 2nd gonadorelin) and CIDR + Cosynch (same as Cosynch but CIDR was inserted for 7 days).ResultThere was no difference (P > 0.05) in ovulation rate to day 9 gonadorelin (88.33% in Boran; 78.79% in Boran*Holstein) and interval from day 9 gonadorelin to ovulation (36.5 ± 1.13 h in Boran and 36.057 ± 1.11 h in Boran*Holstein). Dominant follicle immediate to ovulation (14.95 ± 0.19 mm Vs 19.12 ± 0.49 mm) and corpus luteum size (16.31 ± 0.33 mm Vs 20.28 ± 0.43 mm ) respectively were smaller (P < 0.05) in Boran than Boran*Holstein. Plasma progesterone concentration at PGF2α was higher (P < 0.05) in Boran (11.91 ± 0.74ng/mL) than Boran*Holstein (6.13 ± 0.27ng/mL) but luteolysis rate was lower (P < 0.05) in Boran (87.9%) than Boran-Holstein (96.9%). Cows with CIDR had higher conception rate than cows without CIDR (72.00% Vs 39.02% in Boran*Holstein and 74.07%, Vs 51.52% in Boran respectively). Insemination at 19 h of gonadorelin administration resulted in higher conception rate (78.6% for Boran; 71.43% for Boran*Holstein) than insemination at gonadorelin (69.29% for Boran; 66.67% for Boran*Holstein).ConclusionBoran cows have smaller preovulatory follicles, smaller corpus luteum, large amount of progesterone and lower rate of luteolysis to PGF2α compared to Boran*Holstein. The CL of Boran cattle seems les reactive to PGF2α than Boran*Holstein CL. CIDR significantly improved conception rate in Boran and Boran*Holstein cows.

Focused nutrition during oestrus synchronization in Pelibuey ewes with different body conditions

The aim of this study was to evaluate ovarian follicular activity, ovulation percentage, and body weight change in response to focused nutrition during synchronization of oestrus with an intravaginal device (CIDR®) (9 days) in Pelibuey ewes with high and low body condition. Seventy-two non-pregnant ewes without offspring were randomly distributed to one of four treatments, namely T1: (n = 18) ewes without focused nutrition and low body condition; T2: (n = 18) ewes without focused nutrition and high body condition; T3: (n = 18) ewes with focused nutrition and low body condition; and T4: (n = 18) ewes with focused nutrition and high body condition. While the CIDR device was in place, the ewes with focused nutrition received a supplement of 1.5 kg ewe/day, which contained 2.9 MCal metabolizable energy, 16% crude protein, 88.5% dry matter, 11.8% crude fibre, and 6.7% of ash. The concentration of progesterone (P4) was measured to determine ovulation percentage. The follicular population was quantified (2–3 mm, 4–5 mm, and &gt;6 mm in diameter). The number of follicles between 2–3 mm and 4–5 mm in diameter was similar among treatments. The number of follicles &gt;6 mm in diameter was higher in T4 ewes (2.2 ± 0.2) compared with T1, T2, and T3. The response to oestrus, the onset of oestrus, and the ovulation percentage were similar among treatments. Focused nutrition increased the number of ovarian follicles &gt;6 mm in diameter in ewes with high body condition.

287 Impact of pre- and Post-Natal Nutritional Extremes on Responsiveness of Ovariectomized, Sexually Mature Heifers to a Neurokinin B Agonist During Progesterone Dominance

Abstract Objectives were to test the hypothesis that nutritional extremes during prenatal development interact with postnatal nutrition during the juvenile period of heifers to impact KNDy neuron responsiveness to a neurokinin B (NKB) agonist (Senktide) during progesterone dominance. Heifers were selected from a larger population programmed nutritionally using a 3x2 factorial arrangement of pre- and post-natal diets. Bos indicus-influenced cows (n = 95) were fed to achieve body condition scores (BCS; 1-9 scale) of 3-3.5 (L; thin), 5.5-6 (M; moderate), or 7.5-8 (H; obese) by the onset of the third trimester and maintained thereafter. Heifer offspring were weaned at 3-3.5 mo of age and assigned to either a low- (L; 0.5 kg/day) or high-gain (H; 1 kg/day) diet until 8 mo of age, then fed a common diet until puberty. For the current experiment, heifers (n = 18; 6/group) representing LL, MH, and HH combinations were ovariectomized postpubertally (17.1 mo of age) and received estradiol (E2) replacement to maintain basal E2 concentrations at 2-4 pg/mL. To achieve progesterone dominance, 3 CIDR devices were placed intravaginally 6 days prior to the initiation of Senktide challenge. Heifers were sampled for a 4.5-h period and received intravenous injections of saline or Senktide (14.8 ug/kg I.V.) at 0, 90, and 180 min. Jugular blood samples were collected at 10-min intervals for radioimmunoassay of LH. Irrespective of Senktide treatment, heifers in the MH group had greater pulse amplitudes (P = 0.016) and mean concentrations (P &amp;lt; 0.0001) of LH compared with both the HH and LL groups. Senktide treatment increased (P = 0.003) concentrations of LH compared with saline in all groups; however, the response to Senktide was greatest in the MH group compared with HH and LL. Pre- and postnatal nutritional extremes appear to interact to impact KNDy neuron responsiveness to NKB receptor signaling in heifers.

The Effect of Progestin Source on Some Reproductive Performance in Akkaraman Ewes

This study was conducted to determine the effect of progestin source on some reproductive performance, lamb birth weight and lamb mortality rate in Akkaraman ewes. A total of 40 Akkaraman sheep breed with similar body weight (51.3 ± 1.5 kg) and at least two parturitions were used as experimental animals. In all ewes, the intramuscular injection of PGF2α (2.5 mg) was administered 96 hours before estrus synchronization to obtain corpus luteum regression. The ewes were allocated randomly into two groups according to body weight and ages. Estrus of ewes in the first group (n=20) were synchronized with an intra-vaginal CIDR device containing 0.30 g of natural progesterone. Estrus of ewes in the second group (n=20) were synchronized with an intra-vaginal sponge containing 30 mg flugestone acetate (FGA). CIDR and sponge were withdrawn following 12 days and 600 IU PMSG were injected intramuscularly. After 24 hours from injections, all ewes were introduced to Akkaraman rams and ewes in estrus were recorded. There were no significant differences between natural and synthetic progesterone applications in terms of estrus rate, gestation rate and duration of gestation in Akkaraman ewes. Additionally, lamb birth weight and lamb mortality rates were similar in both experimental groups. However, the application of CIDR increased the total and multiple lamb birth rates of Akkaraman ewes (P

Evaluation of the 7 & 7 Synch and 7-day CO-Synch + CIDR treatment regimens for control of the estrous cycle among beef cows prior to fixed-time artificial insemination with conventional or sex-sorted semen

An experiment was conducted to compare the 7 & 7 Synch and 7-day CO-Synch + controlled internal drug release (CIDR®) treatment regimens before fixed-time artificial insemination (FTAI) of beef cows with conventional or sex-sorted semen. Cows (n = 1538) were blocked based on age and days postpartum (DPP) and randomly assigned to treatment regimen and semen type. Cows assigned to the 7-day CO-Synch + CIDR treatment regimen (n = 769) were administered gonadotropin-releasing hormone (GnRH) and an intravaginal progesterone-releasing insert (CIDR) on Day − 10, and administration of prostaglandin F2α (PG) coincident with CIDR removal on Day − 3. Cows assigned to 7 & 7 Synch (n = 769) were administered PG and a CIDR device on Day − 17, GnRH on Day − 10, and PG coincident with CIDR removal on Day − 3. Cows were administered GnRH coincident with FTAI, which was performed 66 h after CIDR removal with conventional (20 × 106 cells) or sex-sorted (4 × 106 cells) semen. Expression of estrus was affected by treatment regimen (P = 0.01) and by treatment regimen × DPP (P = 0.0004), as a result of imposing the 7 & 7 Synch regimen; therefore, a greater percentage of cows expressed estrus (82% compared with 64%), particularly among cows with greater DPP. Pregnancy percentages resulting from FTAI were less (P < 0.0001) when using sex-sorted semen but greater among cows treated with 7 & 7 Synch (conventional semen: 72%; sex-sorted semen: 52%) compared with 7-day CO-Synch + CIDR (conventional semen: 61%; sex-sorted semen: 44%).

Progesterone supplementation in Holstein heifers subjected to cooling and timed AI during summer: physiological and reproductive variables and thyroid hormone concentrations.

Our aim was to evaluate the effects of progesterone supplementation after fixed-time artificial insemination (FTAI) on physiological and reproductive variables and serum thyroid hormone concentrations of cooled Holstein heifers during a hot summer season. Sixty-nine Holstein heifers were randomly assigned to three treatments: (1) heifers under visual estrus detection and inseminated according to AM-PM rule (n = 23; control (C)), (2) heifers subjected to FTAI after estrus synchronization using a CIDR insert (n = 24; FTAI group), and (3) heifers treated as the FTAI group plus progesterone supplementation between the day 4 and 14 post-insemination with a reused CIDR device (n = 22; FTAI+SP4 group). All heifers were cooled daily with misting and fans. Physiological variables were measured; likewise, blood samples were collected to determine serum progesterone, thyroxine, and triiodothyronine concentrations. Both respiration rate and rectal temperature were similar among treatments. Conception rate was greater (P < 0.05) in C (65.2%) and FTAI+SP4 (59.1%) heifers than in FTAI heifers (33.3%). Serum triiodothyronine and progesterone concentrations of FTAI+SP4 heifers were similar to those of C heifers but greater (P < 0.05) than those of FTAI heifers. In conclusion, progesterone supplementation post-insemination increased conception rate and serum progesterone concentrations without affecting thermoregulation capacity in Holstein heifers subjected to FTAI and cooling during a hot summer season.

55 Effects of concentrate supplementation frequency and amount on growth and reproductive performance of Brangus heifers

Abstract A 2-yr study evaluated the impacts of supplementation frequency and amount on growth and puberty attainment of Brangus heifers. On d 0 of each year, 64 Brangus heifers were stratified by BW and age (244 ± 4 kg; 311 ± 18 d) and assigned to 1 of 16 bahiagrass pastures (4 heifers/pasture). Treatments were randomly assigned to pasture (4 pastures/treatment) in a 2 × 2 factorial design and consisted of heifers offered a soybean hulls-based supplement DM at 1.25% or 1.75% of BW delivered either daily (7X) or 3 times weekly (3X; Monday, Wednesday, and Friday). On d 56, heifers were inserted with a CIDR device for 14 d, followed by administration of PGF2α and a timed-AI+GnRH protocol on d 89. Heifers were exposed to bulls from d 89 to 167. Data were analyzed using the SAS GLIMMIX procedure. No rate × frequency interactions were detected (P ≥ 0.20). Overall ADG was greater for 7X vs. 3X heifers (P = 0.007). Daily supplementation increased (P ≤ 0.03) the percentage of pubertal heifers prior to CIDR insertion and at AI compared to 3X supplementation; however, percentage of pregnant heifers did not differ (P = 0.70). Supplementation at 1.25% vs. 1.75% enhanced the overall ADG (P = 0.02) but did not impact (P = 0.18) the percentage of pubertal heifers before CIDR insertion. After the puberty induction protocol, heifers supplemented at 1.75% of BW achieved greater puberty attainment at time of AI (P = 0.05) and final pregnancy rates (P = 0.02) than heifers supplemented at 1.25% of BW. When a puberty induction protocol was included, the percentage of pregnant Brangus heifers were not affected by supplementation frequency (daily vs. 3 times weekly) but enhanced when the supplement dry matter amount was offered at 1.75 vs. 1.25% of body weight.

The effect of pre-breeding vitamin E and selenium injection on reproductive performance, antioxidant status, and progesterone concentration in estrus-synchronized Mehraban ewes.

The present study was conducted to assess the effects of pre-breeding vitamin E and selenium (ESe) injections on the reproductive performance, antioxidant status, and serum progesterone (P4) concentration in estrus-synchronized Mehraban ewes. During the breeding season, 38 ewes (3-4years) were divided into two groups (n = 18), and the synchronization of estrus was achieved by intravaginal insertion of 0.3g progesterone CIDR device for 13days followed by 350IU eCG at CIDR withdrawal. Ewes were kept under pasture conditions and exposed to Mehraban rams 48h following CIDR withdrawal. The experimental treatments were control and ESe injection. The ESe group was received three intramuscular (5mL) injections of Ese (0.5mg/mL of selenium as sodium selenite and 50IU vitamin E as DL-α- tocopheryl) once every 2weeks. Specifically, Ese was administered at 2weeks before CIDR insertion, at the times of CIDR insertion and CIDR withdrawal. Fertility, prolificacy, lambing rate, and birth weight were recorded after parturition. Blood samples were collected at CIDR insertion, CIDR withdrawal, 5, 10, and 15days after ram exposure. Fertility, prolificacy, lambing rate, and birth weight did not improve by Ese treatment, but viabilityof lambs was higher in ESe than control (P < 0.05). Serum total antioxidant capacity at day 5 and P4 at day 10 after ram exposure was higher in ESe than control (P < 0.05). In conclusion, sheep breeders can use ESe at CIDR insertion and withdrawal times to potentiate antioxidant status and progesterone profile of estrus-synchronized Mehraban ewes.

164 Gonadotrophin-releasing hormone injection and colour flow Doppler ultrasound of the preovulatory follicle as a tool to increase pregnancy outcome after timed AI in beef cows

The aims of this study were to determine (1) the association between Doppler vascularisation scores (DVS) of the preovulatory follicle (POF) and fertility of beef cows submitted to timed AI (TAI) and (2) whether cows with low DVS benefit from a gonadotrophin-releasing hormone (GnRH) treatment at TAI. Multiparous lactating Nelore cows (Bos indicus; n=69) from a commercial beef farm in the state of Rondônia, Brazil, were enrolled in this study. Cows received 2mg of oestradiol benzoate intramuscularly (Bioestrogen, Biogénesis Bagó) and an intravaginal progesterone-releasing device (1.9g of progesterone; controlled internal drug release, CIDR) to synchronise follicular wave emergence on Day 0. The CIDR device was removed and cows were treated with 150μg of D-cloprostenol intramuscularly (prostaglandin F2α analogue; Croniben), 1mg of oestradiol cypionate intramuscularly, and 300IU of equine chorionic gonadotrophin (Novormon) intramuscularly on Day 8. Cows were then painted with a tail chalk marker to identify those displaying oestrus. All cows were submitted to TAI 48h after CIDR removal. At TAI, occurrence of oestrus was recorded and all cows were examined using transrectal ultrasonography. Blood flow of the POF was evaluated using colour Doppler imaging. Colour Doppler signals present on the follicular wall were subjectively scored using a 1-to-4 scale (1=absence or very low blood flow, and 4=intense blood flow detected on most of the follicular wall surface) adapted from Ginther (2007Ultrasonic Imaging and Animal Reproduction: Color-Doppler Ultrasonography, pages 87-114). Then, cows were divided into three groups according their DVS of the POF: (1) high DVS (DVS ≥3; n=36), (2) low DVS (DVS &amp;lt;3; n=16), and (3) low DVS (DVS &amp;lt;3; n=17) plus a GnRH treatment at TAI. The diameter of the POF was analysed using analysis of variance (PROC GLIMMIX of SAS; SAS Institute Inc.), and the means were compared among groups using Tukey's test. The proportion of cows that displayed oestrus and pregnancy rates was analysed using chi-square test. Cows in the high-DVS group had a larger POF than cows in the low-DVS and low-DVS-GnRH groups (13.2±0.2, 11.7±0.5, and 12.2±0.4, respectively; P&amp;lt;0.05). The proportion of cows that displayed oestrus was greater (P&amp;lt;0.05) in the high-DVS group (72%, 26/36) than in the low-DVS (37.5%, 6/16) or low-DVS-GnRH (53%, 9/17) groups. Finally, greater (P&amp;lt;0.05) pregnancy rates were observed in cows from the high-DVS (47.2%; 17/36) and low-DVS-GnRH (52.9%; 9/17) groups than in cows from the low-DVS group (18.7%; 3/16). The preliminary results from this study demonstrated that diameter of POF is positively associated with DVS. Moreover, cows that presented POF with higher DVS are more likely to become pregnant, and the administration of GnRH to females with low DVS can increase the fertility of beef cows submitted to TAI protocols. This study received funding support from Embrapa (MP1/PC3 project no. 01.03.14.011.00.00) and from CNPq (universal project no. 407307/2016-8).

Effect of estradiol cypionate on estrus expression and pregnancy in timed artificially inseminated beef cows

Several studies have shown that cows displaying estrus before timed artificial insemination (TAI) are more likely to become pregnant. However, the most frequently used ovulation-inducing agents by South American beef operations, estradiol esters, may artificially induce estrus in treated cows. The hypotheses tested in the present study were: 1) estradiol cypionate (EC) treatment will induce estrus in ovariectomized cows, and 2) cows that exhibit estrus following administration of EC and eCG will have lower P/AI compared to those that do not receive EC. In Experiment 1, 14 ovariectomized cows were used in a cross-over design with an interval of 30 d between replicates. On Day 0, all cows received 2 mg of estradiol benzoate and a CIDR device and 12.5 mg of Dinoprost (PGF2α analogue) on Day 7. On Day 9, the CIDR devices were removed and cows were placed at random into one of two experimental groups and administered either 0.5 mL of canola oil (Control, CTL group, n = 14) or 1 mg of EC (EC group, n = 14). Estrotect estrus detection patches were used and cows were observed 4 times daily to determine the occurrence of estrus. More EC-treated cows showed estrus (12/14, 85.7%) than canola oil-treated cows (0/14; P < 0,001). The interval from EC treatment to estrus was 46 ± 3.7 h. In Experiment 2, 804 postpartum Nelore cows were treated as in Experiment 1, except that all cows received 300 IU of equine chorionic gonadotrophin at CIDR removal, and were randomly divided into 3 groups: 1) EC group (n = 269) received 1 mg i.m. of EC on Day 9; 2) EC-GnRH group (n = 269) received EC on Day 9, and were inseminated on observation of estrus, while those not showing estrus received GnRH on Day 11; and, 3) Estrus-GnRH group (n = 266) did not receive EC on Day 9 and were inseminated on observation of estrus. Those in Groups 2 and 3 that did not show estrus received GnRH on Day 11 at the time of TAI. The proportion of cows showing estrus was greater (P < 0.0001) in EC (68.7%, 185/269) and EC-GnRH (57.2%; 154/269) groups than in the Estrus-GnRH group (35.7%, 95/266). However, no difference in P/AI was observed among the groups (P = 0.87). These results show that EC will induce estrus in ovariectomized cows, and that EC treatment increased the proportion of intact cows exhibiting estrus in a TAI protocol without reducing P/AI.

150 Administration of prostaglandin F2α 24 h prior to CIDR removal impacts reproductive performance of suckled beef cows assigned to the 7-d CO-Synch + CIDR protocol

Abstract Angus-influenced cows received 100 µg of GnRH and a CIDR device containing 1.38 g of progesterone (P4) on d 0, and were randomly assigned to 25-mg injection of PGF2α on d 6 (PG6; n = 147) or d 7 (PG7; n = 162). The CIDR device was removed on d 7, and cows received 100 µg of GnRH and artificial insemination (AI) on d 10. An estrus detection patch was attached to the tailhed of each cow on d 7, and estrus expression assessed at AI (&gt; 50% coating removal). Blood samples were collected on d 0 to determine the presence of a functional corpus luteum via plasma P4 (CL, P4 ≥ 1.0 ng/mL; NOCL P4&lt; 1.0 ng/ mL). A subset of cows (70 cows/treatment) were assigned to ultrasonography at AI to verify dominant follicle diameter (DFD). Blood samples for plasma P4 analysis were collected (42 cows/treatment) on d 6, and on d 7 at CIDR removal and 1 h later. A similar proportion of PG6 and PG7 cows were classified as CL (P = 0.38). Plasma P4 at CIDR removal and 1 h later were less in PG6 vs. PG7 cows classified as CL (1.81 vs. 3.99 and 1.06 vs. 2.89 ng/mL), and did not differ (P ≥ 0.43) within NOCL. Estrus expression was greater in PG6 vs. PG7 cows classified as CL (72.8 vs. 48.3%), but similar (P = 0.96) within NOCL. Pregnancy rates did not differ between treatments (P = 0.53), despite a numerical difference (P = 0.15) between PG6 vs. PG7 cows classified as CL (65.5 vs. 55.0%). No other treatment effects were detected (P ≥ 0.20). Hence, PGF2α administration 24 h prior to CIDR removal appears to benefit reproductive performance of beef cows with a functional CL at the beginning of the 7-d CO-Synch + CIDR protocol

The use of progesterone intravaginal devices is superior to use of the ram effect at hastening the reproductive performance in transitional Targhee ewes

To compare the use of controlled intravaginal drug release (CIDR, EAZI-BREED™ CIDR® Sheep, USA, Zoetis) with the ram effect, a combination of CIDR and ram effect and the addition of P.G.600® to each of these scenarios on their contribution to inducing the onset of cyclicity and their ability to improve reproductive efficiency in a commercial sheep flock, a randomized clinical trial was conducted. Multiparous ewes (n = 283) were randomly assigned to one of six treatments prior to intact male introduction on day 0: only CIDR devices (day −5 to day 0) (n = 40), exposure to two vasectomized rams (d-14 to d0) (n = 55), CIDR (d-5 to d0) and an intramuscular injection of P.G.600® (d0) (n = 40), exposure to two vasectomized rams (d-14 to d0) and treated with CIDR devices (day −5 to day 0) (n = 40). exposure to vasectomized rams (d-14 to d0), CIDR (d-5 to d0) and an intramuscular injection ofP.G.600®, (d0) (n = 38), and a control group, without exposure to vasectomized rams, CIDRs or P.G.600® (n = 70). Ewes were exposed to intact males on day 0. Days to lambing from the earliest expected lambing date at 150 days post introduction of rams was compared between groups with survival analysis. The mean survival time was significantly shorter in all groups that used CIDR compared to the control group (P < 0.003, adjusted for multiple comparisons). The addition of a teaser ram or a P.G.600® injection did not change survival time. In a Cox proportional hazard model for time to lambing, the use of CIDR had a hazard ratio of 1.62 (95% CI: 1.07, 2.45, P = 0.23), while other variables (teaser ram, P.G.600®) were not significant. In a Poisson regression for the number of lambs born to each ewe, P.G.600® was not a significant variable, even when adjusted for age of ewe (P = 0.74). The combination of the ram effect and CIDRs did not have an additive effect. The use of CIDR shortened time to cyclicity in study ewes and may provide an attractive option to advance lambing season. Further studies on the economics of this method are warranted.

Does royal jelly have a reproductive effect on progesterone-treated goats?

Introduction: Some methods for inducing/synchronizing oestrus and ovulation in goats require the injection of equine chorionic gonadotrophin (eCG). The objective of this study was to determine whether royal jelly (RJ) can be a subs-titute for eCG in CIDR-treated dairy goats. Methods: Sixty-six primiparous goats received the CIDR device for twelve days in April. The eCG group (n=22) was injec-ted with 200 IU of the gonadotropin when the intravaginal device was removed; the RJ group (n=22) received a daily intramuscular injection of 1 g of RJ during the period of CIDR treatment; the CIDR group (n=22) did not receive any additional treatment. A fourth group (Con, n=20) was used as control and received no treat-ment at all. Oestrus response, ovulation and fertility were recorded. Results: The oestrus percentage was higher in eCG (95%, p&lt;0.05) than in the remaining groups (RJ, 41%; CIDR, 36% and Con, 0%) and occurred at shorter intervals (eCG, 35±2.3; RJ, 66±4.6; CIDR, 59±2; h±se; p&lt;0.05). Ovulation was higher in eCG (91%, p&lt;0.05), and RJ and CIDR were not different between them (50% vs 41%, p&gt;0.05). No ovula-tion was recorded in the Con group. The percentage of fertile and birthing animals after 148-158 days was greater in the eCG (91%, p&lt;0.05) compared to other groups (RJ, 36%; CIDR, 36%, Con, 0%), whereas it was not different between the RJ, CIDR and Con groups (p&gt;0.05). Conclusion: There was no evidence of a reproductive effect of RJ on progesterone-treated goats.

134 The effect of follicle-stimulating hormone and equine chorionic gonadotropin injection protocols on laparoscopic ovum pickup in prepubertal Kiko goats

In vitro fertilization has served as a great tool in the human and bovine field in its ability to treat infertility in females. The purpose of this study was to compare hormone injection treatments in goats using the laparoscopic ovum pickup technique. A crossover trial was conducted to evaluate 2 superovulation injection protocols [a multiple-injection FSH (F) and a one-injection FSH-eCG (F+E)] for their ability to increase recovery of oocytes using laparoscopic ovum pickup (LOPU) technique in 10 prepubertal Kiko does. Does were randomly assigned to 2 sequence groups (n=5). Period 1 initiated on 28 July 2017 and Period 2 on 12 August 2017. A CIDR device was inserted on Day 0 and removed after LOPU. On Day 6 of each period, 3mL of prostaglandin F2α was given IM to each doe. F-treated does received (IM) twice daily injections of 15, 12.5, 10, and 7.5mg of FSH, whereas F+E-treated does received (IM) 80mg of FSH and 300 international units (IU) of eCG. Thirty-six hours after injection, follicles were aspirated using LOPU. Treatment response measurements included total follicles observed, oocyte recovery rate, and blastocyst rate. Total follicles observed were higher (P=0.004) in F+E-treated does (305 follicles) than F-treated does (236 follicles). Neither oocyte recovery rates (F+E=41.5% and F=38.1%) nor blastocysts rates (F+E=18% and F=32%) were affected (P&amp;gt;0.05) by injection protocol. In conclusion, we summarise that multiple injections of FSH can results in a higher number of follicles produced; however, this does not have a subsequent effect on IVF and development rates.

Effect of synchronization protocols on reproductive indices, progesterone profile and fertility under subtropical environmental conditions in repeat breeder Holstein cows

The objectives were to evaluate the reproductive indices and survival analysis of pregnancy outcomes in multiparous repeat breeder Holstein cows (n=557). The cows were synchronized to ovulate by Ovsynch, new controlled internal drug release device (N-CIDRsynch), and once-used CIDR device (U-CIDRsynch). The pregnancy per AI at 28days post-insemination (P/AI 28) in the N-CIDRsynch group (28.75%) was significantly (COR=1.49; p=0.011) greater than that reported in the Ovsynch (23.46%) and U-CIDRsynch (21.73%) groups. Furthermore, the pregnancy per AI at day 75 post-insemination (P/AI 75) in the N-CIDRsynch group was significantly greater than the Ovysync group (COR=1.35; p=0.050). The repeat breeder cows received a N-CIDR device had a significantly higher progesterone level on day 2 and day 4 of CIDR insertion (1.38 and 1.67ng/ml, respectively) than those received a U-CIDR device or the control group (p=0.012 and 0.001, respectively). The Cox regression model recorded significant associations for synchronization protocols, THI at the TAI and season of calving with the hazard of P/AI 28 and P/AI 75 (p=0.044 and 0.046; 0.001 and 0.005; 0.003 and 0.001, respectively). Multiparous repeat breeder cows (>3) had a lower hazard ratio (HR) of P/AI 28 than that reported in the reference (2nd parity) group (HR=0.74, p=0.050). The repeat breeder cows inseminated at 76-80 and >80 temperature-humidity index (THI) had significantly lower HR of P/AI 28 than those inseminated at the baseline (<70) THI value (HR=0.73 and 0.30, p=0.036 and 0.001, respectively). The current results indicate that the use of N-CIDR synch protocol may achieve satisfactory pregnancy outcomes in repeat breeder cows.

Different protocols using PGF2α as ovulation inducer in Nelore cows subjected to estradiol-progesterone timed AI based protocols

The objective of this study was to evaluate the effect of a PGF2α-analogue (PGF) on ovulation and pregnancy rates after timed artificial insemination (TAI) in cattle. In Experiment 1 cows received an intravaginal progesterone-releasing device (CIDR) plus 2 mg im of estradiol benzoate (EB) on Day 0. The CIDR devices were removed on Day 8, and all cows received 150 μg im of d-cloprostenol (PGF2α-analogue), 300 IU of eCG and 1 mg of estradiol cypionate (ECP) im. On Day 9, cows were randomly assigned into two groups: 1) ECP Group (n = 17), that did not receive any further treatment; and 2) ECP-PG Group (n = 14) that were given 150 μg of d-cloprostenol (PGF) as adjuvant stimulus for ovulation. No difference between groups was detected in interval for ovulation (P = 0.5), and in the proportion of cows ovulating (P = 0.09). In Experiment 2, multiparous suckling crossbred Aberdeen Angus cows (n = 260), were treated into two groups, similarly as Experiment 1; ECP group (n = 122), and ECP-PG group (n = 138). All females were TAI on Day 10. The proportion of cows treated with ECP that became pregnant was 54.9% (67/122), and cows treated with ECP plus PGF was 55.1% (76/138; P = 0.9). In Experiment 3, 686 Nelore cows, 40 to 50 days postpartum, were treated as Experiment 1 (ECP group), however, on Day 8 cows were divided into 3 groups: ECP Group (n = 216); PGF-SC Group (n = 228), in which cows did not receive ECP and were given an additional subcutaneous injection of PGF on Day 8; and PGF–IM Group (n = 242), in which cows also did not receive ECP on Day 8 and were given an additional injection of PGF im on Day 9. On Day 10, estrus was evaluated at timed AI (TAI). There was no difference in the diameter of the dominant follicle at CIDR removal and at TAI, and pregnancy per AI among groups (P > 0.05). However, the proportion of cows that displayed estrus between CIDR removal and TAI was higher in ECP group than in PGF-SC and PGF-IM groups (P < 0.001). Cows that displayed estrus has higher P/AI than cows that did not (P = 0.008). In conclusion, these results suggested that intramuscular or subcutaneous injection of PGF2α could be successfully used to induce ovulation in cattle undergoing TAI, with similar pregnancy rates when compared with ECP. The subcutaneous injection of PGF on the same day of CIDR removal could be an interesting alternative due it reduces cattle management to obtain similar results.

Effect of the disinfection treatment of used intravaginal devices on the concentration of progesterone on cows under dry tropical conditions

The objective of the study was to compare the effect of disinfection/cleaning of CIDR devices on serum progesterone concentrations (P4) in Suizo x Cebu cows, which received during eight days a new intra-vaginal device (CIDR; T1), used device, sterilized by autoclave (T2) or a used device, disinfected with chlorine (T3). A complete randomized design with three replicates per treatment was applied. The used CIDR devices were used previously in cows. Blood samples were collected at 0, 15, 30 min, as well as at 1, 3 and 6 h and then each 12 h until tenth day , with respect to the moment of the insertion of the CIDR. The P4 concentration was determined by radioimmunoassay. Mean concentrations of P4 were similar among treatments (T1, 1.7 ± 0.9 ng/mL; T2, 1.31 ± 0.65 ng/mL; and T3, 1.33 ± 3.19 ng/mL; P<0.05). In conclusion, the process of disinfection/cleaning of the CIDR devices did not affect the availability of progestogen; therefore the CIDR could be used for estrous synchronization.

Use of a five-day progesterone-based timed artificial insemination protocol for dairy water buffaloes

The objective of this study was to determine the effect of a short five-day (5 d) progesterone-based timed artificial insemination (TAI) protocol on the time of ovulation and fertility in dairy water buffaloes. In experiment 1, 30 dairy buffaloes were subjected to one of two estrous synchronization protocols. Females in the control group (n=17) were administered 2 mg of estradiol benzoate (EB), and an intravaginal progesterone-releasing device (CIDR) was inserted on day -12. On day -3, CIDR inserts were removed and all cows were treated with 150 ?g of D-cloprostenol (a PGF2?-analogue). Forty-eight hours after CIDR removal, all cows received 100 µg of gonadotropin-releasing hormone (GnRH). Females assigned to the short 5 d group (n=13) received treatment similar to the control group, except that the CIDR device was inserted on day -8, and the EB treatment was eliminated. In experiment 2, 51 dairy buffaloes were separated into control (n=27) and short 5 d (n=24) groups that received the same treatment as described for cows in experiment 1, except that all females were inseminated 16 to 18 h after GnRH injection. The use of a short 5 d progesterone-based TAI protocol with or without treatment with EB on day 0 did not affect the time of ovulation and pregnancy per artificial insemination in lactating water buffaloes. Thus, we suggest that the short 5 d TAI protocol may be successfully used as an alternative to induce ovulation in dairy buffaloes, with the particular advantages of avoiding EB treatment and a shorter interval from the beginning of the protocol to TAI.