Controlled Intravaginal Drug Release Research Articles

PSVI-12 Comparison of a Visual Health Scoring System with Vaginal Temperatures of Newly Received Feedlot Heifers

Abstract Newly received feedlot cattle frequently succumb to bovine respiratory disease (BRD), which can be visually diagnosed and medically treated by employing a 4-point scoring system based on depression, appetite, respiration, and temperature (DART). Using this system, cattle are treated with antimicrobial medications for BRD if they have a rectal temperature (RT) ≥ 40°C and a DART score of 2 (scale = 1 to 4), or if they have a DART score of 3 or 4 regardless of the 40°C RT threshold. However, cattle often exhibit several visible clinical symptoms of BRD but do not have an RT above the 40°C threshold to warrant medical treatment. The objective of this study was to evaluate if DART scoring could be used to identify cattle with elevated vaginal temperatures (VT) throughout a 28-day receiving period. Upon feedlot arrival, 198 crossbred heifers (primarily Angus influence; initial BW = 219 ± 63 kg) were initially processed, weighed, and allocated to one of 10 soil-surfaced pens (12 x 35 m; 20 heifers per pen). A blank Controlled Intravaginal Drug Release (CIDR) device attached with an indwelling temperature probe (iButton DS1925L) was inserted vaginally into each heifer to collect and store VT every 10 minutes for 28 days. All heifers were evaluated daily (0700 h) for signs of morbidity by three individuals (blinded from each other) implementing the DART scoring system. Individual DART evaluations were then pooled prior to determination of heifers needing further evaluation for medical treatment. Results confirmed that DART score increases as VT increases (P < 0.001). Similarly, mean time DART ≥ 2 (TDART≥2) increased as mean time VT ≥ 40°C (TVT≥40) increased (P < 0.001). Accuracy of DART ≥ 2 to VT ≥ 40°C analogous by day is denoted as (MATCH). Simple regression analysis of MATCH and TVT≥40 for determining accuracy of visually diagnosing clinical BRD, was MATCH = 0.89 – 0.71 × TVT≥40 (r2 = 0.70; P < 0.001). The accuracy to visually diagnose BRD decreases as the number of days spent with a VT ≥ 40°C increases. Average daily gain decreased (P < 0.001) as TDART≥2 and TVT≥40 increased. The BRD symptoms indicating high VT and DART score (P ≤ 0.01) were nasal discharge, anorexia, abnormal respiration, and teeth grinding. Additionally, weakness, cough, lowered head, and ocular discharge indicate greater DART score (P ≤ 0.01). Basophils and hemoglobin decreased with elevated VT and DART score (P ≤ 0.02). Monocytes increased with increased DART score (P ≤ 0.04). In conclusion, data from this evaluation employing VT sensors and the DART scoring method provided an overview of how effective clinical BRD can be visually diagnosed, therefore contributing to the improvement and development of more effective strategies for identifying respiratory diseases in feedlot cattle.

Application of gender-ablated semen during timed artificial insemination following oestrous synchronization in dairy and beef cows.

The objectives of this study were to compare oestrous synchronization expression and conception rate following timed artificial insemination (TAI) with frozen-thawed X-sexed or unsexed semen in dairy and beef cows. For this study, 227 cows (dairy, n= 130 and beef, n= 97) were assigned to a 9-day Ovsynch + controlled intravaginal drug release (CIDR) protocol. All cows were TAI using X-sexed or unsexed semen from 8sires. Each semen type was obtained from 4 sires [2 dairy (Holstein Friesian) and 2 beef (Angus)]. Pregnancy detection was performed on Days 35, 65 and 95 following TAI by transrectal ultrasonography and hand palpation. The proportion of oestrus expression was higher in dairy (85.3%) cows compared with beef (65.0%) cows (p< .05). Overall, dairy (X-sexed, 61.9% and unsexed, 62.0%) cows had greater conception rates on Day 35 compared to beef (X-sexed, 56.0% and unsexed, 52.2%) cows (p<.05). Concurrently, on Day 95, overall conception rates in dairy (X-sexed, 41.4% and unsexed, 48.5%) cows were greater than beef (X-sexed, 38.0% and unsexed, 37.0%) cows (p< .05). Pregnancy/embryo losses between Days 35 and 65 in dairy (X-sexed, 33.3% and unsexed, 18.2%) cows and beef (X-sexed, 28.6% and unsexed, 29.2%) cows were recorded (p< .05). Dairy (X-sexed, 7.7% and unsexed, 8.3%) cows had higher incidence of pregnancy losses between Days 66 and 95 when compared to beef (X-sexed, 5.0% and unsexed, 0.0%) cows (p< .05). Oestrous expression and conception rates in dairy and beef cows were satisfactory. Advanced reproductive biotechnologies can successfully utilize gender-ablated semen in organized emerging cattle farming systems.

Ovarian hormones and antioxidant biomarkers in dromedary camels synchronized with new and re-used controlled intravaginal drug release (CIDR)/GPG (Ovsynch) program during breeding season.

This study aimed to investigate the effect of CIDR, re-used wCIDR, and Ovsynch protocols for the synchronization of follicular waves on ovarian hormones, oxidative stress, and antioxidant biomarkers during the breeding season. Dromedary camels (N = 18) were divided into three equal groups. The first group received CIDR. The second group received previously used wCIDR after thorough cleaning and disinfection. The third group was subjected to GPG protocol. Progesterone (P4), estradiol (E2) l, total antioxidant capacity (TAC), catalase (CAT), lipid peroxide product (MDA), nitric oxide (NO), and glutathione reduced (GSH) were measured. Days during CIDR affected P4 (P =0.0001), E2 (P =0.047), TAC (P =0.01), NO (P =0.028), and GSH (P =0.005). Days during re-used wCIDR effected P4, TAC, CAT, NO, GSH, and MDA (P ≤0.001). Days during GPG effected P4, E2, TAC, GSH (P =0.0001), MDA (P =0.036), and NO (P =0.02). CIDR-treated camels had high P4 (P =0.0001), E2 (P =0.0001), TAC (P =0.012), and NO (P =0.0001), with low GSH (P =0.001), and MDA (P =0.003). Exogenous progesterone improved ovarian hormones and the antioxidant capacity and minimized the oxidative stress than the GPG treatment and is recommended for future reproductive management of camels.

Factors affecting conception rate of hair ewes after laparoscopic insemination with chilled semen under tropical conditions

The objective was to evaluate the effect of some factors on the conception rate of hair ewes using laparoscopic intrauterine insemination with chilled semen under tropical conditions. Data on 1200 inseminations carried out in Pelibuey, Blackbelly, Katahdin and Dorper ewes from 19 farms were used. Estrous was synchronized using vaginal sponges or a controlled intravaginal drug release (CIDR) device by 12days. At the withdrawal of the device (sponge/CIDR) 200 or 250 IU of equine chorionic gonadotropin (eCG) was applied. Insemination was carried out 54–56h after withdrawal of the device using chilled semen with 150 million spermatozoa per dose. Ultrasound conception diagnosis was carried out 35–40 d after insemination. The effects of ewe breed, age of ewe (1–4 years), body condition score (low, middle and high), type of device (sponge and CIDR), dose of eCG (200 and 250 IU), year of insemination (2010–2012), season (hot-dry, hot-humid; fresh-humid), inseminator (5 inseminators) and simple interactions on conception rate were determined using binary logistic regression. The overall conception rate was 66.4%. There was not significant interactions of main effects. Only breed, body condition score (BCS) and year of insemination influenced (P<0.05) conception rate. Blackbelly (73.1%) and Pelibuey (68.9%) ewes had the highest conception rates as compared to Dorper (61.4%) and Katahdin breeds (62.4%). The conception rate was better in the ewes of middle body condition (68.1%) than ewes of low BCS (64.2%). Under the conditions of this study, the conception rate of ewes, using laparoscopic intrauterine insemination with chilled semen was influenced by ewe breed, BCS and year of insemination.

Comparison of Oestrous Synchronization Response and Pregnancy Rate of Village Cows Following Timed Artificial Insemination in KwaZulu-Natal and Limpopo Provinces

The objectives of the current study were to evaluate the estrous response and pregnancy rate following timed artificial insemination (TAI) with frozen-thawed semen in cows. The study was carried out in cows at different villages of KwaZulu-Natal (KZN; n = 160) and Limpopo provinces (L; n = 171). Cows were selected randomly as presented by the farmers, regardless of parity, age, breed and body weight following pregnancy diagnosis. The cows were grouped according to breed type and body condition score (BCS) on a scale of 1-5. Selected cows were inserted a controlled intravaginal drug release (CIDR&#174) and removed on day 8, followed by administration of prostaglandin. Heat was observed on day 9 with the aid of heat mount detectors (HMD) that were placed on the individual cow’s tail head. Cows on heat were then inseminated twice at 12 hours interval. Pregnancy diagnosis was performed by an ultrasound scanner and rectal palpation 90 days after TAI. Data were analyzed using SAS 2006. Estrous responses were 100% in KZN and 99% in Limpopo. The lowest pregnancy rate was recorded in Brahman and Bonsmara type cows with BCS ≤ 2.5 regardless of province. Interestingly, Nguni type cows with BCS ≤ 2.5 had higher average pregnancy rate of 59.5% in Limpopo and 53.5% in KZN. However, cows with BCS ≥ 3 had better pregnancy rate regardless of breed type and province. In conclusion, village cows can be synchronized successfully and inseminated with frozen-thawed semen. However, pregnancy rates are low in cows with lower body condition. Village Nguni type cows were not affected by body condition scoring as they had higher and similar pregnancy rate as those that had body condition of ≥3.

Short communication: Effect of cross ventilation with or without evaporative pads on core body temperature and resting time of lactating cows

A trial was performed to assess the effect of evaporative pads on core body temperature (CBT) and lying behavior of lactating Holstein cows housed in cross-ventilated freestall facilities in a humid environment. This trial was undertaken in 2 barns equipped with (EP) or without (NP) evaporative pads. Each facility had 4 pens, 1 baffle/pen, and a nominal width of 122m. Stocking density was higher (123.4 vs. 113.1%) and freestalls were slightly shorter (2.3 vs. 2.4m) and narrower (1.16 vs. 1.21m) in EP compared with NP barns. In each pen, lying behavior of 20 cows was monitored using electronic data loggers that recorded at 1-min intervals. A subset (n=14) of these cows within each pen were also fitted with temperature loggers attached to blank controlled intravaginal drug release devices to determine CBT every 5min. Ambient conditions were collected every 15min. Individual cow lying duration and lying bouts were assessed for each cow, as well as time spent standing and CBT within the following categories: CBT <38.6°C, and CBT >38.6, >38.9, >39.2, >39.4, and >39.7°C. These variables were analyzed using pen as the experimental unit, with cow and day as additional random effects. The average maximum ambient conditions over the 9d were 25°C and 78.74% relative humidity. No differences were observed in lying duration and number of lying bouts over the 9-d period, with overall means of 696±31min/d and 12.6±0.5 bouts/d. The EP cows spent 170min/d longer with a CBT <38.6°C and 107min/d less with CBT >39.2°C than did NP cows. Cooling with evaporative pads tended to increase time spent lying with a CBT >8.6°C and lying bouts/d for EP cows versus NP cows. Results from this trial show that even under mild heat stress, evaporative cooling in cross-ventilated facilities can decrease CBT and tended to increase lying time.

Effect of Feeding Longan Dimocarpus longan Residue before Estrus Synchronization on Reproductive Performance in Ewes

To evaluate the effect of feeding longan residue (longan fruit; grade C) before estrus synchronization on reproductive performance in sheep, sixteen ewes observed in estrus were selected and randomly assigned to 2 groups: control group (n=8) received the maintenance diet whiles the longan-supplemented group (n=8) received the maintenance diet plus 300 g DM/head/day of longan fruit for 17 days. Blood concentrations of glucose, insulin, progesterone (P4), and estradiol (E2), and follicular population were recorded. After the nutritional treatments, all ewes were synchronized for estrus with controlled intravaginal drug release (CIDR) devices and 400 IU pregnant mare serum gonadotropin. Ewes exhibiting estrus were subjected to assisted natural mating by rams. Ewes fed longan-supplemented diet had greater feed intake than ewes fed the control diet. Glucose concentrations were higher in longan-supplemented than those in control ewes on days 7, 14, and 17. Insulin concentrations were only higher in longan-supplemented group than those in control group on day 17. The longan-supplemented ewes had higher E2 concentrations than non-supplemented ewes on days 14 and 17. On days 14 and 17, numbers of total follicles had significantly greater in longan-supplemented ewes compared with control ewes. Estrous response and conception rate were not different between control and treatment ewes. It was concluded that the 17 days of dietary supplementation stimulate ovary (total follicles) ready to respond to the synchronization of estrus. However, dietary supplementation with longan fruit in ewes prior to the start of the estrus synchronization did not enhance reproductive performance.

Effect of follicle age on conception rate in beef heifers1

The objective of this study was to determine the effect of age of the ovulatory follicle on fertility in beef heifers. Ovulation was synchronized with the 5 d CO-Synch + controlled intravaginal drug release (CIDR) program in heifers in Montana (MT; n = 162, Hereford and Angus Crossbred) and Ohio (OH; n = 170, Angus Crossbred). All heifers received estradiol benzoate (EB; 1 mg/500 kg BW, [i.m.]) 6 d after the final GnRH of the synchronization program to induce follicular atresia and emergence of a new follicular wave (NFW) followed by prostaglandin F2α (PGF(2α); 25 mg, i.m.) administration either 5 d ("young" follicle [YF]; n = 158) or 9 d ("mature" follicle [MF]; n = 174) after EB. Estrous detection was performed for 5 d after PGF(2α) with AI approximately 12 h after onset of estrus. Ovarian ultrasonography (MT location only) was performed in YF and MF at EB, 5 d after EB, PGF(2α), and AI. Heifers in MT (n = 20) and OH (n = 18) that were not presynchronized or did not initiate a NFW were excluded from further analyses, resulting in 142 and 152 heifers in MT and OH, respectively. Heifers from the MF treatment in MT that initiated a second NFW after EB but before PGF(2α) (MF2; n = 14) were excluded from the primary analysis. In the secondary analysis, the MF2 group was compared to MF and YF treatments in MT. Estrous response was similar (90%; 252/280) between treatments and locations. Proestrus interval (from PGF(2α) to estrus) and age of the ovulatory follicle at AI were similar for MF heifers between locations (54.6 ± 1.7 h and 8.3 ± 0.07 h) but were greater (P < 0.01) for YF heifers in OH (78.5 ± 1.4 h and 5.3 ± 0.06 h) than MT (67.4 ± 1.6 h and 4.8 ± 0.06 h; treatment × location, P < 0.01). However, conception rate did not differ for MF (63.8%; 74/116) and YF (67.0%; 91/136) treatments. In the MT heifers, follicle size and follicle age at AI in the YF treatment (10.4 ± 0.15 mm and 4.8 ± 0.06 d, respectively) was less (P < 0.01) than in the MF treatment (11.0 ± 0.18 mm and 8.3 ± 0.11 d, respectively), but conception rate to AI did not differ between treatments in MT. In the MF2 group proestrus interval was greater (P < 0.01); hence, diameter of the ovulatory follicle and age were similar to that for the YF treatment. Conception rate to AI did not differ between MF2, MF, and YF (61.5, 63.3, and 64.7%, respectively) in MT. In conclusion, manipulation of age of the nonpersistent ovulatory follicle at spontaneous ovulation did not influence conception rate.

Changes in Concentrations of Reproductive Hormones during Estrus Synchronization in Dairy Heifers

The objective of this work was to analyze the concentrations of progesterone (P4) and estrogen (E2) hormones changed during estrus synchronization in dairy heifers. Estrus synchronization was carried out with CIDRⓇ (Controlled Intravaginal Drug Release) devices. Corpus luteum (CL) was classified into three grades based on its size and palpable characteristics. The concentrations of P4 and E2 were measured by enzyme-amplified chemiluminescence. Serum P4 concentration was markedly low at the estrus stage (36 hrs after removal of CIDR) compared to other stages, while E2 concentration was kept high during estrus stage. The serum P4 concentration was highest in the CL classified into gradeⅠ. These results indicate that P4 concentration could be used as a criteria for determining recipients for artificial insemination or embryo transfer in dairy cattle.

Determination of the appropriate delivery of prostaglandin F2α in the five-day CO-Synch + controlled intravaginal drug release protocol in suckled beef cows1

The objective of this experiment was to determine if 2 doses of prostaglandin F(2α) (PGF) administered concurrently at controlled intravaginal drug release (CIDR) removal was an efficacious method for delivery of PGF in the 5-d CO-Synch + CIDR protocol. Postpartum beef cows (n = 2,465) from 13 herds in 8 states were enrolled in the 5-d CO-Synch + CIDR protocol and assigned to receive 2 doses of PGF (25 mg/dose) 8 h apart with the initial injection given at CIDR insert removal (8h-PGF), 2 doses (25 mg/dose) of PGF delivered in 2 injection sites, both administered at CIDR insert removal (Co-PGF), or a single 25-mg dose of PGF at CIDR insert removal (1x-PGF). Cows were fixed timed-artificially inseminated (FTAI) 72 h after CIDR removal concurrent with GnRH administration. Estrus-cycling status (54% cyclic) was determined by evaluation of progesterone in 2 blood samples collected before CIDR insertion. Determination of pregnancy was performed by transrectal ultrasonography 39 ± 0.1 d after FTAI and at least 35 d after the conclusion of the breeding season. Fixed timed-AI pregnancy rates were greater (P < 0.05) for the 8h-PGF (55%) than the 1x-PGF (48%) treatment, with the Co-PGF (51%) treatment intermediate and not different (P > 0.10) from the other treatments. Contrast analysis demonstrated that cows receiving 50 mg of PGF (8h-PGF and Co-PGF) had greater (P < 0.05) FTAI pregnancy rates than those receiving 25 mg (1x-PGF). Pregnancy rates to FTAI were greater (P < 0.05) in cyclic (55%) than noncyclic (47%) and greater (P < 0.05) in multiparous (≥3 yr of age; 54%; n = 1,940) than primiparous cows (40%; n = 525). Luteolysis after PGF treatment was assessed in a subset of cows (n = 277) and treatment tended (P = 0.09) to affect the proportion of cows having luteolysis. The percentage of cows that had luteolysis was least in the 1x-PGF treatment (89%) and greatest in the 8h-PGF treatment (97%), with the Co-PGF treatment (94%) being intermediate. Breeding season pregnancy rate (88%) did not differ (P > 0.10) among treatments but was greater (P < 0.01) in multiparous (90%) than primiparous (78%) cows. In summary, 50 mg of PGF was required in the 5-d CO-Synch + CIDR protocol to maximize pregnancy rates; however, pregnancy rate did not differ when 50 mg of PGF was administered simultaneously with CIDR removal or split with 25 mg administered at 0 and 8 h after CIDR removal.

Ovarian response and pregnancy rate following different doses of eCG treatment in Chall ewes

The purpose of the study was to investigate the effects of different doses of equine chorionic gonadotropin (eCG) treatment on follicular development, ovulation and pregnancy rate during the breeding season in fat-tailed Chall ewes. Seventy-two cycling (62.5±2.5kg), multiparous Iranian Chall ewes were used in the trial. The ewes were randomly allocated to 6 groups (n=12/group). Estrus was synchronized with the aid of controlled intravaginal drug release (CIDR) devices, inserted for 14 days. At the time of CIDR removal (day 14), the ewes received i.m. either 0 (control group, G0), 450 (G450), 550 (G550), 650 (G650), 750 (G750) or 850 (G850)IU eCG. Vasectomized rams were used to detect estrus in the ewes from 24h after CIDR removal. Ovarian follicular activity was monitored with the aid of transrectal ultrasonography on the day of CIDR insertion (day 0) and daily from the day of eCG treatment (day 14), until estrus (day 16). During these days, blood samples were collected for the determination of plasma progesterone and estradiol concentrations. Laparoscopic intrauterine inseminations were conducted 54–60h after CIDR removal. The number of CL's and pregnancy diagnosis was recorded using ultrasonography 7 and 54 days following AI, respectively. Half of ewes in control group and most of the ewes treated with eCG showed signs of estrus within 36h of CIDR removal. The ewes in groups G750 and G850 recorded the highest number of large follicles at estrus and CL's 7 days later. The pregnancy rate in groups G550 (75.0%) and G650 (75.0%) was higher (P<0.05) than that in the other groups. The ovarian response and estradiol concentration, as well as pregnancy rate showed that 550 or 650IU eCG treatment is the most effective doses in improving the pregnancy rate in Iranian Chall ewes.

Characterization of Oestrous Induction Response, Oestrous Duration, Fecundity and Fertility in Awassi Ewes During the Non‐breeding Season Utilizing both CIDR and Intravaginal Sponge Treatments

The aim of this study was to investigate characterization of oestrous response, onset of induced oestrus, oestrous duration, fecundity and fertility in Awassi ewes treatment with intravaginal sponges and Controlled Intravaginal Drug Release (CIDR) devices in combination with pregnant mare serum gonadotropin (PMSG) under local environmental conditions during the non-breeding season. A total of 62 ewes were divided into three groups. Group CIDR (n = 20) was treated with CIDR devices for 12 days and 400 IU PMSG was injected upon removal of the CIDR. For ewes in Group Sponge (SP) (n = 24), 30 mg fluorogestone acetate was administered to the sheep for 12 days and 400 IU PMSG was injected upon withdrawal of the sponge. Group Control (CON) (n = 18) served as a control group and received no treatment. Adult, intact and sexually experienced Awassi rams were introduced to all groups at the time when the intravaginal devices were removed. There were no significant differences in terms of oestrous response (CIDR: 90%, SP: 87.5%), time to onset of oestrus and duration of induced oestrus between the CIDR and SP groups. The oestrous response of treatment groups was significantly greater (p < 0.05) than in the control ewes. There were no significant differences in pregnancy (CIDR: 70%, SP: 70.8%), lambing (CIDR: 85%, SP: 79.2%) and fecundity rates between ewes treated with CIDR and those treated with sponges. However, pregnancy and lambing rates were significantly (p < 0.05) higher in ewes treated with CIDR or sponges when compared with those in the control group. It was concluded that it is possible to induce fertile oestrus, successful pregnancy and lambing with the treatment of either CIDR or intravaginal sponge in combination with PMSG in Awassi ewes during the non-breeding season.

Strategies to improve fertility in postpartum multiparous Bos indicus cows submitted to a fixed-time insemination protocol with gonadotropin-releasing hormone and prostaglandin F2α1

In Exp. 1, we evaluated the effects of 2 lengths of progesterone exposure [CIDR (controlled intravaginal drug release); 7 vs. 14 d] before a modified CO-Synch protocol [50.0-microg injection of GnRH 6.5 d before a 25.0-mg injection of PGF(2alpha) followed by another injection of GnRH and fixed-time AI (TAI) 2 d after PGF(2alpha)], with or without temporary weaning (TW) before GnRH treatments, on fertility of suckled multiparous Bos indicus cows (n = 283) and on calf performance. Timed AI pregnancy rates for cows receiving 7 d CIDR + TW, 7 d CIDR, 14 d CIDR + TW, and 14 d CIDR were 53, 47, 46, and 41%, respectively (P > 0.10). Calves submitted to two 48-h TW 6 d apart had decreased mean BW at 240 d (187.9 +/- 2.7 vs. 195.5 +/- 2.7 kg; P < 0.05), but BW at 420 d was not affected by TW (240.1 +/- 5.1 kg). In Exp. 2, we evaluated the effect of no treatment and treatment with or without a CIDR insert between GnRH and PGF(2alpha) treatments of a modified CO-Synch protocol on pregnancy rate to TAI, and throughout a 90-d breeding season in suckled multiparous Bos indicus cows (n = 453). The inclusion of a CIDR between first GnRH and PGF(2alpha) treatments of a modified CO-Synch protocol did not improve pregnancy rate (29 and 33% for cows receiving CO-Synch + CIDR and CO-Synch protocol, respectively), and cycling cows had poorer TAI pregnancy rates than anestrous cows treated with either synchronization protocol (21.7 vs. 40.7%; P < 0.05). However, regardless of treatment with CIDR, cows submitted to TAI protocol had greater (P < 0.05) pregnancy rates at 30 (54.8 vs. 11.2%), 60 (72.1 vs. 38.8%), and 90 d (82.0 vs. 57.9%) of breeding season than untreated cows.

The effect of addition of equine chorionic gonadotropin to a progesterone-based estrous synchronization protocol in buffaloes ( Bubalus bubalis) under tropical conditions

Poor estrus expression and anestrus decrease the reproductive efficiency of buffaloes. The objective of this study was to determine whether the addition of equine chorionic gonadotropin (eCG) to an estrous synchronization protocol and timed insemination could improve ovulation and pregnancy rates of anestrous buffalo cows under tropical conditions. The study population comprised 65 lactating Murrah buffalo cows which were assigned to CIDR ( n = 33) or CIDR + eCG ( n = 32) treatment groups. Cows in the CIDR group were fitted for 8 d with a controlled intravaginal drug release (CIDR) device containing 1.38 g progesterone, received GnRH (10 μg i.m.) on D 0, PGF 2α (750 μg i.m.) on D 7, and GnRH (10 μg i.m.) on D 9; whereas cows in the CIDR + eCG group received the same treatment plus eCG (500 IU, i.m.) at the time of PGF 2α treatment. All cows were inseminated 16–20 h after the second GnRH treatment. Blood samples were obtained 10 d before the start of synchronization treatment (Day –10) and at the onset of treatment (Day 0). Cows with plasma progesterone concentrations <1 ng/mL recorded in both samples (Low–Low levels of P4) were classified as non-cyclic cows. Similarly, when either one or both of the sample pair contained concentrations of serum progesterone ≥1 ng/mL (High–High, Low–High, or High–Low levels of P4), the buffaloes were classified as cyclic cows. Ovulation rate, defined as the number of buffaloes with at least one corpus luteum 10 days after insemination, was significantly higher ( P = 0.018) in the CIDR + eCG (84.4%) cows than in the CIDR cows (57.6%). Pregnancy rate was numerically lower in CIDR (27.3%) than CIDR + eCG (40.6%) cows, though differences were not significant ( P = 0.25). Pregnancy rates for CIDR + eCG cows were similar to that of cows inseminated after natural estrus (40.9%; 29/71). In the non-cyclic animals, higher ovulation rates ( P = 0.026) were recorded for the CIDR + eCG (81%) than for the CIDR cows (47.4%). Our results indicate that the addition of eCG to a progesterone-based estrous synchronization regimen substantially improves the ovulation rate in non-cyclic buffaloes. When this treatment is followed by timed AI, pregnancy rates achieved in anestrous buffaloes, whether cyclic and non-cyclic, may approach the rates observed in cows inseminated at natural estrus.

Facilitation of sexual behavior in French-Alpine goats treated with intravaginal progesterone-releasing devices and estradiol during the breeding and nonbreeding seasons.

The effectiveness of administering progesterone (P4) using controlled intravaginal drug release (CIDR) devices on estradiol (E2)-induced sexual behaviors was examined in ovariectomized (ovx) French-Alpine goats during the fall and spring. Estradiol-induced attractivity and receptivity were facilitated during the spring when P4-filled CIDR devices were removed 24 or 48 h before injection of 30 microg of E2. During the fall, attractivity was also facilitated by CIDR removal 24 h prior to E2 injection, whereas E2-induced receptivity was unaffected by removal of the CIDR at this interval. Concentrations of P4 in circulation during the 3 d of treatment with a CIDR were similar to those during the late luteal phase of the estrous cycle in intact goats. Treatment with P4-filled CIDR for 3 d, followed by injection with 30 microg of E2 24 h after removal, was determined to be a useful model for inducing sexual behavior in a physiologically relevant manner, and it may also be an effective means for facilitating estrus detection due to the high frequency of display of sexual behavior during a predictable time period following steroid treatment.