Controlled Internal Drug Release Insert Research Articles

Effect of the feeding condition and number of dominant follicles on oestrus synchronization in Swamp buffalo

The research aimed to assess how feeding conditions and the number of the dominant follicles (DF) influence oestrus synchronization in swamp buffaloes. A total of 170 swamp female buffaloes raised in semi-grazing and housekeeping were included in the study. The synchronization used CIDR method and the follicles on the day of CIDR (Controlled Internal Drug Releasing) insert and removal were tracked by sonography. The results indicated that the age of first mating, age at first calving, and caving interval showed no significant differences in the two feeding conditions. The number of follicles at CIDR insertion and removal decreased in semi-grazing, but increased in housekeeping buffaloes. The percentage of buffalo without DF, one DF, and two DFs at CIDR withdrawal did not differ statistically. The percentage of estrus was 100% in both groups. Pregnancy rates were 53.18% in semi- grazing and 52.63% in housekeeping. The onset of oestrus was similar, but the duration of oestrus was longer in the buffaloes without DF than those with one or two DFs. The percentage of pregnant buffaloes in the group without DF was significantly lower than that in the other two groups. In summary, the efficiency of oestrus synchronization did not differ between semi-grazing and housekeeping methods. Buffaloes without DF displayed longer oestrus periods and lower pregnancy rates compared to those with one or two DFs in the ovarian system.

15 Influence of early progesterone removal on follicular development, estrus expression, and pregnancy rates in presynchronized beef cows

Abstract The objective of this study was to evaluate the impact of early progesterone removal on pregnancy rates to fixed-time artificial insemination (FTAI) in presynchronized beef cows. Postpartum beef cows (n = 922; body condition score = 4.9 ± 0.77; days postpartum = 77.3 ± 20.77 d) from 7 locations were enrolled in a completely randomized design. Within location, cows were stratified by parity and days postpartum before being randomly assigned to 1 of 2 treatments: 1) 7&7 Synch: Cows received a controlled internal drug release insert (CIDR) and a 25-mg injection of prostaglandin F2α (PG1; d 0). Cows received 100 μg of GnRH on d 7 and the CIDR was removed 7 d later, concurrently with a second prostaglandin F2α (PG2) injection (d 14). Cows received a second injection of GnRH and were FTAI 60-66 h after PG2 (d 17); 2) 7&6 Synch: Cows received the same treatment as 7&7 Synch cows; however, CIDR removal and PG2 were performed on d 13, and cows were FTAI 60-66 h after CIDR removal. Ovarian ultrasonography was performed to determine follicle diameter and CL presence at PG2 and FTAI in a subset of cows (n = 40). Estrus detection patches were utilized to evaluate estrus expression between PG2 and FTAI. Pregnancy diagnosis was performed 28-35 d after FTAI. Cows exposed to the 7&7 Synch tended to have larger follicle diameter at PG2 compared with 7&6 Synch cows (P = 0.09); however, there were no differences in follicle diameter at FTAI. Cows that expressed estrus tended to have larger follicle diameter at FTAI compared with cows that failed to express estrus (P = 0.10). Follicular growth between PG2 and FTAI, percentage of cows with a corpus luteum at PG2, and ovulation rate were not impacted by treatment (P ≥ 0.56). No differences were determined between treatments for estrus expression (7&7 Synch: 77.1 ± 5.91; 7&6 Synch: 74.6 ± 6.28; P = 0.50) or pregnancy rates to FTAI (7&7 Synch: 60.1 ± 4.32; 7&6 Synch: 58.2 ± 4.26; P = 0.69). In conclusion, early removal of progesterone did not impact pregnancy rates in presynchronized beef cows. Thus, the 7&6 Synch protocol described herein may be used as an alternative to the conventional 7&7 Synch protocol without compromising fertility.

Influence of repeated estrus synchronization treatment on hormone secretion, growth, and development of dairy goats.

In large-scale intensive farms, dairy goats often undergo frequent estrus synchronization (ES) treatment, which may result in a decline in reproductive performance; however, the underlying mechanism remains unclear. The present study aimed to investigate the effect of pregnant mare serum gonadotropin (PMSG) and progesterone (P4)-mediated ES treatment on fertility in dairy goats, while also identifying key metabolic and endocrine mechanisms that influence reproductive performance in does subjected to repeated ES treatment. Forty-eight Saanen does were randomly assigned to two groups (24 goats each) that received ES treatments either thrice fortnightly (3-PMSG) or once (1-PMSG) simultaneously with the third ES treatment of the 3-PMSG group during the breeding season. ES treatment was performed via the intravaginal insertion of a controlled internal drug release (CIDR) device impregnated with 300 mg P4, followed by 300 IU PMSG injections 48 h before CIDR withdrawal. Blood was collected to detect the level of hormones and blood biochemical indices. Additionally, estrus rate, fecundity rate, body weight, size, and lactation performance were measured. The results showed that repeated ES treatment markedly decreased the estrus rate and fecundity rate of goats. Among the does in all groups, there was no substantial difference in follicle stimulating hormone, luteinising hormone, gonadotropin-releasing hormone, melatonin, growth hormone, PMSG, total cholesterol, total protein, and glucose levels, as well as the body weight, body size, and lactation performance. Repeated ES treatment elevated estrogen (E2) levels 36, 48, and 72 h post-CIDR removal; increased P4 upon CIDR insertion; and raised PMSG antibody levels 24, 48, and 72 h post-CIDR removal. The results suggest that elevated anti-PMSG levels are the primary reason for the decline in ES efficiency, and that high E2 and P4 levels at some time points also impair reproductive performance. These findings provide novel insights into the metabolic effects of repeated PMSG stimulation in goats, guiding future reproductive hormone use in breeding practices.

PSXII-8 Effects of Pre-Synchronization with Short-Term Melengesterol Acetate in Nulliparous Beef Heifers

Abstract Conception rates in nulliparous beef heifers can be greatly influenced by their ability to reach puberty at or prior to the initiation of a breeding season. Previous research has analyzed the efficacy of utilizing both long and short-term exposure to a source of progesterone via a controlled internal drug release insert (CIDR) prior to estrous synchronization with timed artificial insemination (TAI) and found improved conception rates. The purpose of this study was to evaluate the effects of feeding melengesterol acetate (MGA) immediately and 10 days before estrous synchronization. Ninety-three crossbred heifers (395.67 ± 5.37 kg) were blocked by BW, genetics, and reproductive tract scores and allotted to 3 treatments. The 3 treatment groups were: 7-day Co-synch + CIDR without presynchronization (CON, n = 31); 2cc PGF2α (Lutalyse) followed by melengesterol acetate feeding for 7 d before the start of the 7-day Co-synch + CIDR program (PRE, n = 31); and 2 mL Lutalyse followed by MGA feeding for 7 d followed 10 d later by the start of the 7-day Co-synch + CIDR program (PRE+10, n = 31). The 7-day Co-synch + CIDR protocol was initiated on d 0 by administering a 2 mL IM injection of GnRH and placing a CIDR into the vagina. The CIDRs were removed 7 days later and accompanied by 2 ml IM injection of PGF2α. An injection of GnRH occurred 60 to 66 hours following PGF2α at TAI with frozen semen from a single bull. Ten days after TAI, heifers were exposed to a bull. Estrotect patches were applied throughout the study to assess estrous behavior. Ovaries were visualized 24 hours post TAI to determine whether ovulation occurred. Pregnancy was determined on days 40, 64, and 109 post TAI via transrectal ultrasonography. Blood was collected via jugular venipuncture (d -19, MGA initiation and termination, d 0, d 7, and d 9) and serum progesterone determined. Performance data were analyzed using the MIXED procedure and conception data were analyzed using the GLIMMIX procedure of SAS. Heifers in the PRE+10 treatment group had higher levels of progesterone (P = 0.04) at d 0 than PRE heifers. At d7 there was a tendency (P = 0.07) for PRE+10 heifers to have greater concentrations of progesterone than PRE, but did not differ by d 9 (TAI, P = 0.36). TAI conception rates in heifers in the PRE treatment group (63%) tended (P = 0.09) to be greater compared with the controls (35%) and not different from PRE+10 (43%), with no differences in season-long pregnancy rates (P > 0.15). Presynchronization with MGA immediately before TAI synchronization can increase conception rates early in the breeding season in beef heifers.

Use of deslorelin acetate to advance ovulation in goats for timed artificial insemination

The objective of this study was to determine the efficacy of deslorelin in advancing ovulation for timed artificial insemination (AI) protocols in goats. We hypothesized that deslorelin treatment advances the onset of ovulation and improves AI pregnancy rates. Does were synchronized using a 5-day CIDR (controlled internal drug releasing insert) protocol with prostaglandin treatment at CIDR insertion. For Experiment 1, does received 0.2 mg of intramuscular deslorelin (n = 9) or saline (control, n = 10) at CIDR removal. Serial blood collections and transrectal ultrasonography were performed to assess ovarian dynamics and identify ovulation. For Experiment 2, does received 0.2 mg of intramuscular deslorelin (n = 42), 5 ml of PMSG (pregnant mare serum gonadotropin)/hCG (human chorionic gonadotropin) (n = 42), or were left untreated (control, n = 42) at CIDR removal, and were subsequently bred by transcervical AI with fresh semen after 48 to 56 hours. Pregnancy diagnosis was performed at 50 and 90 days after AI. In Experiment 1, compared to control does, deslorelin-treated does had an increased (p < 0.01) number of ovulations and increased (p < 0.01) serum estradiol concentrations from 48 to 72 hours after CIDR removal. Serum progesterone concentrations did not differ between treatments. In Experiment 2, there was a main effect (p = 0.02) of treatment on pregnancy rates, with control does tending (p = 0.06) to have greater pregnancy rates than those treated with deslorelin or PMSG/hCG. Deslorelin treatment also resulted in decreased (p = 0.04) breeding season pregnancy rates and increased (p = 0.05) number of cycles to achieve pregnancy compared to control does. These results demonstrated that deslorelin not only has a super-ovulatory effect but also, at the dose given, can negatively impact does’ subsequent ovarian function and ability to achieve pregnancy.

A single dose of FSH or hCG during a split-time AI program did not enhance follicular growth or pregnancy per artificial insemination in beef heifers

ABSTRACT The objective of this study was to evaluate the effect of a low dose of hCG or FSH on follicle growth and pregnancy per artificial insemination (AI) in crossbreed beef heifers subjected to a split-time AI program. All heifers (n = 386) were subjected to a 7-d Co-synch protocol and an intravaginal controlled internal drug release (CIDR) device (GnRH and CIDR insertion; 7 days later PGF2α, CIDR removal, and application of a tail head estrus detection patch; 36 hours later AI of heifers detected in estrus, 24 hours later timed AI of remaining heifers). At CIDR removal, heifers were randomly assigned to receive either 150 IU of hCG, 20 mg of FSH, or remained as untreated controls. The diameter of the preovulatory follicle and the pregnancy per AI did not differ among treatments. A smaller (P = 0.035) proportion of heifers in the hCG group were detected in estrus compared with control. Additionally, the incidence of premature ovulation was greater (P < 0.01) among heifers treated with hCG compared with control. In conclusion, using a low dosage of hCG or FSH at the time of device removal did not affect pre-ovulatory follicle growth or the proportion of pregnant heifers.

55 Investigating the Potential Benefits of an Immunostimulant (Mycobacterium Cell Wall Fraction) Treatment on Increased Pregnancy Success of Embryo Transfer Recipients

Abstract Modulating the vaginal and uterine microbiome through the use of immunostimulants has the potential to improve fertility in cattle. The object of this study was to evaluate the potential benefits of an immunostimulant, mycobacterium cell wall fraction (MCWF), to increase pregnancy success of embryo transfer (ET) recipients. The three main objectives of this study were: determining if injecting ET recipient cows with MCWF increased proportion of cows with a corpus luteum (CL) on ET day, identifying differences in CL volume and progesterone concentration at the time of ET, and determining if ET recipients that received MCWF have greater pregnancy rate. A total of 926 beef cows at eight different locations were enrolled in this study. Primiparous and multiparous cattle were enrolled in a 7-day CO-Synch + CIDR estrous synchronization protocol. During this protocol, cows received an injection of GnRH (100-μg) at CIDR (controlled internal drug release) insertion [d -9], a prostaglandin F2α injection (25 mg), and CIDR removal [d-2] followed by another injection of GnRH (100 μg; d 0) within 60-66 hours after CIDR removal. At each location at (d 0), cows were sorted based on BCS and days post-partum and randomly assigned to one of two treatments: 1) MCWF- a single intramuscular injection (5 mL) of MCWF at (d 0; Amplimune, NovaVive Inc.; n = 452) or 2) Control- a single intramuscular injection (5 mL) of saline (n = 474). Seven days after (d 7), cows were examined by ultrasonography to determine if a CL was present. Recipient cows that had a CL received ET with a frozen or fresh in vivo or in vitro produced embryo in the ipsilateral uterine horn to the CL, with embryo type and grade balanced between treatments. Blood samples were collected in one location (n = 98) for analysis of plasma concentration of progesterone on (d 7) ET day. Pregnancy diagnosis was then performed by ultrasonography between 30 and 90 days of gestation. Data were analyzed using the GLIMMIX and MIXED procedures of SAS. Cow BCS and days postpartum were similar (P &amp;gt; 0.10) between treatments (5.5 ± 0.6 and 103 ± 14 days, respectively). Recipient cow utilization rate was similar between treatments (P = 0.49; 81.2 ± 0.42%). At the time of ET MCWF had larger CL than Control cows (5,768.6 ± 133.7 and 5,408.0 ± 128.5 mm3, respectively, P = 0.03). and increased progesterone concentration (2.68 ± 0.17 and 2.18 ± 0.14 ng/mL, respectively, P = 0.01). However, pregnancy rate to ET was similar (P = 0.922) between treatments (60.9 and 61.3 ± 0.05% for Control and MCWF, respectively). In conclusion, treatment of ET recipient cows with MCWF increased CL volume and concentration of progesterone at the time of ET but failed to generate greater pregnancy rates.

Haematological Responses following Oestrus synchronisation and superovulation protocols in West African Dwarf Goats

Experiments were performed to evaluate the haematological (erythrocyte and leucocyte parameters) response of West African Dwarf goats following oestrus synchronisation and superovulation protocol. Twenty-four clinically healthy female goats aged 2.34 ± 0.4 years and average body weight of 13.83 ± 0.7 kg was used for the experiment. The goats were divided into two groups. Group I goats was synchronized using Controlled Internal Drug Release (CIDR) for 18 days with the first day of insertion as day 0. On day 16 following CIDR insertion into the vagina, a single dose of 500 IU equine chorionic gonadotropin (eCG) was administered to each doe intramuscularly while group II served as the control was subjected to the same housing and environmental conditions but was not synchronized. superovulation was induced with porcine follicle stimulating hormone (pFSH) which was injected intramuscularly at a rate of 5mg/kg in reducing doses twice a day at 06.00 h and 18.00 h for 3 days starting from 48hr i.e., 2 days before CIDR removal (day 17). A blood sample of 5 mL was collected by jugular venipuncture of each of the goats before the protocol (Day 0) and at the end of the protocol (Day 18). All erythrocyte parameters evaluated showed a significantly higher value in group II (control) compared to group I post-oestrus synchronisation while total leucocyte count, neutrophil count and neutrophil/lymphocyte ratio values obtained after the protocol were also higher in group I (P &lt; 0.05) compared to group II. It is therefore concluded that oestrus synchronisation and superovulation may elicit stress in West African Dwarf goats and an appropriate antioxidant should be part of the protocol.

Effects of Pre-Synchronization With Prostaglandin F2α and a Progestin, and Delayed Insemination on Pregnancy Rates With Sexed Semen in Replacement Beef Heifers

To determine the effects of pre-synchronization and delayed fixed-time artificial insemination (TAI) on pregnancy rates (PR/AI) with sexed semen, 1,844 beef heifers were enrolled in a completely randomized design at 12 locations. Within a location, the heifers were randomly assigned to one of the five treatments: (1 and 2), heifers were administered prostaglandin F2α (PGF) on Day -7, gonadotropin-releasing hormone (GnRH), and a controlled internal drug releasing (CIDR) insert on Day 0, PGF at CIDR removal on Day 7, and a second injection of GnRH at TAI 72 h later with either conventional (CTRL72-CNV) or sexed semen (CTRL72-SEX); (3 and 4), treated the same as CTRL72 but received a CIDR insert on Day -7 at PGF administration and TAI at 60 h with either conventional (CIDR60-CNV) or sexed semen (CIDR60-SEX); (5), treated the same as CIDR60 but had TAI delayed to 72 h with sexed semen (CIDR72-SEX). Estrus detection patches were applied to all heifers on Day 7 and were evaluated for activation at TAI. Estrus expression did not differ (p = 0.92) between CIDR60 and CIDR72 heifers, but was greater (p &amp;lt; 0.001) in CIDR60 and CIDR72 heifers compared with CTRL72 heifers. Among treatments, PR/AI differed (p &amp;lt; 0.001) and were greater (p ≤ 0.003) in CTRL72-CNV and CIDR60-CNV heifers than CIDR60-SEX and CIDR72-SEX heifers (51.6 and 48.1 vs. 37.5 and 25.3%, respectively). In addition, PR/AI were greater (p &amp;lt; 0.001) in CTRL72-SEX and CIDR60-SEX heifers when compared with CIDR72-SEX (42.0 and 37.5 vs. 25.3%, respectively) heifers but only tended (p = 0.09) to differ between CTRL72-SEX and CIDR60-CNV heifers. No differences (p = 0.33) were determined between CTRL72-CNV and CIDR60-CNV or between CTRL72-SEX and CIDR60-SEX heifers (p = 0.22). In conclusion, no differences were determined between heifers pre-synchronized with only PGF and those pre-synchronized with PGF and a CIDR insert when inseminated with either conventional or sexed semen. Therefore, the use of a CIDR insert for an additional 7 days was not beneficial to PR/AI when heifers were TAI at 60 h with either conventional or sexed semen. Furthermore, delaying TAI to 72 h with sexed semen after pre-synchronization with both PGF and a CIDR insert had a negative impact on PR/AI.

19 Evaluation of Fixed-time Artificial Insemination and Estrus Expression in Angus-cross Heifers with Female Sex-sorted Semen Using 6-day and 7-day CIDR Protocols at Multiple Time Intervals

Abstract The objective was to investigate the influence of progesterone exposure time and breeding time on fixed-time artificial insemination (FTAI) protocols using sex-sorted semen in Angus-cross heifers (n = 85; mean BW = 324 kg.). Heifers were assigned randomly into four treatment groups. Treatments 1 and 2 used a 6-day CO-synch + controlled internal drug release (CIDR) protocol with gonadotropin releasing hormone (GnRH) administration and CIDR insertion on day 0 and prostaglandin F2α (PGF) administration on day 6, upon simultaneous CIDR removal. Treatment 1 heifers underwent FTAI 72 h post CIDR removal, and Treatment 2 heifers underwent FTAI 80 h post CIDR removal. Treatments 3 and 4 used a 7-d CO-synch + CIDR protocol with GnRH administration and CIDR insertion on d 0 and PGF administration on d 7, upon simultaneous CIDR removal. Treatment 3 heifers underwent FTAI 54 h post CIDR removal, and Treatment 4 heifers underwent FTAI 62 h post CIDR removal. Estrus expression was determined using an estrus detection patch (Estrotect™, Rockway Inc., Spring Valley, WI). Estrus expression was classified as a patch with 50% or more of the color rubbed off and the absence of estrus expression as a patch with less than 50% of the color rubbed off. All heifers were inseminated using female sex-sorted semen from a single Angus sire (SexedULTRA 4M™, STgenetics, Navasota, TX). Pregnancy was determined by ultrasound 57 d following FTAI. Pregnancy rates and patch scores were analyzed using the GLIMMIX procedure of SAS 9.4 with treatment as a fixed effect. There was no effect of treatment on the first service AI rates (P = 0.91) or on estrus expression (P = 0.17) in heifers. In conclusion, the combinations of progesterone and breeding time in this study did not affect first service AI conception rates or estrus expression in beef cattle heifers.

Follicular wave emergence and fertility following estrogen based synchronization regimen in anestrus buffaloes (Bubalus bubalis)

The study was undertaken to study the follicular changes around the time of new wave emergence following estradiol-17 (E-17) + controlled internal drug release (CIDR) based synchronization in 30 anestrus buffaloes. The animals were divided in two Groups, viz. Group I and II. In Group I (n=20), on day 0 (beginning of experiment), buffaloes were administered CIDR device (1.38 g P4) and concurrently received 1.5 mg estradiol-17 in 1.5 ml canola oil (i. m.). On day 9, CIDR was removed and a prostaglandin (PG) 2 analogue (500 μg, i. m.) was administered. On day 11, buffaloes were administered gonadotropin releasing hormone (GnRH) analogue (20 μg, i.m.) and inseminated twice at 12 h and 24 h following GnRH injection. Group II (control, n=10) received the CIDR-based protocol except the administration of estradiol at the time of CIDR insert. Ovaries were examined for follicular wave emergence, ovulation of dominant follicles at estrus and subsequent conception at 45 days of insemination. The mean diameter of largest follicle was reduced from 8 mm (0th day) to 4 mm on the day of wave emergence (WE), i.e. day 4 in Group I but day 6 in control. The mean number of 4-5 mm follicle was 5.7 in Group I and 4.8 in control on the days of WE. Ovulation and conception rates achieved were 85 vs 60% and 47 vs 30% respectively. In conclusion the new wave emergence was induced earlier by estradiol-17 administered along with CIDR which ultimately resulted in more ovulation and conception rate in buffalo. Estrogen based protocols might be adopted to improve fertility in anestrum buffaloes.

Association of gastrointestinal parasite burden, serum cytokines and hormones concentrations, and pregnancy in Angus-cross beef cows

The objective was to elucidate the relationships among gastrointestinal (GI) parasite load, serum cytokines (Th 1 – Interleukin (IL) 2, Interferon (IFN) γ and Tumor necrosis factor (TNF) α; Th 2- IL4, IL6, and IL10) levels, hormones (progesterone, cortisol, 8-epi-prostaglandin F2 alpha (isoprostane), prolactin, substance-p, and prostaglandin F metabolites) concentrations, and pregnancy in beef cattle. Angus-cross beef cows (n = 700; age, 3–8 y) were blocked by age and body condition score (BCS, 1–9), and were randomly assigned to treatment (n = 350, TRT, 50 mg of eprinomectin/50 kg BW, im) or control (n = 350, CON, no treatment) on Day -30. Cows were synchronized using Controlled Internal Drug Release insert (CIDR) + CO-Synch protocol and artificially inseminated at a fixed time on Day 0 (66 h after CIDR removal). Fecal samples were collected to determine fecal egg count per gram (FEG, McMaster method) on Days -30, -23, -16, -7, 7, 0, 16 and 23, and blood samples were collected on Days -7, 0, 7, 16 and 23. Serum cytokines were determined on Days -7, 0, 7, 16 and 23, and circulating hormones were measured on Day 16. BCS were recorded on Day 16 following artificial insemination (AI), and pregnancy status was diagnosed on Day 30 and 60. Pregnancy/AI varied among treatment groups on Day 30 [TRT, 62.0% (217/350); CON, 54.9% (192/350) (P = 0.05)] and Day 60 [TRT, 60.9% (213/350); CON, 51.7% (181/350) (P < 0.05)]. Pregnancy loss between 30 and 60 days for TRT and CON groups were 1.8% (4/217) and 5.7% (11/192), respectively (P < 0.05). The BCS on Day 16 did not differ among treatment groups (P> 0.1). Four groups of 40 cows were selected based on their pregnancy status and treatment: pregnant, TRT; non-pregnant, TRT; pregnant, CON; and non-pregnant, CON to compare the mean FEG, cytokines, and hormones levels. The FEG and cytokine concentrations were significantly (P < 0.05) influenced by treatment, pregnancy status, day, treatment by pregnancy status, and treatment by day. Day 16 hormone concentrations were considerably influenced by treatment, pregnancy status, and treatment by pregnancy. Although FEG on Day -30 did not differ among the groups (P> 0.1), it was lower in treated, pregnant cows compared with cows in other three groups from Day -23 onwards (P < 0.05). Overall and pairwise comparisons showed that serum concentrations of Type 1 cytokines, IL2, IFNγ, and TNFα were lower (P < 0.05) from gestational Day 7 onwards in treated, pregnant cows compared with cows in other three groups. In contrast, serum concentrations of Type 2 cytokines, IL4, IL6 and IL10 were greater (P < 0.05) from gestational Day 7 onwards in treated, pregnant cows compared with cows in other groups. Serum concentrations of progesterone was greater and other hormones were lower for pregnant cows in TRT group compared to cows in other groups on gestational Day 16. In conclusion, GI parasite load was reduced; Th 1 cytokines levels were decreased; Th 2 cytokines concentrations were increased; progesterone level was increased; and cortisol, substance-P, prolactin, isoprostane, and PGFM were decreased in pregnant, TRT cows. These changes also resulted in an increase in P/AI. It is plausible that direct and bidirectional host-parasite interactions mediated by cytokines and hormones may have promoted maternal tolerance of an immunologically diverse conceptus and the establishment of pregnancy.

Use of GnRH for Synchronization of the Follicular Wave in Assisted Reproductive Technologies in Sheep: A Preliminary Study.

Simple SummaryThe present study aimed to set up a short-term protocol for synchronization of follicular wave emergence in sheep, concomitant with estrus synchronization, which would improve ovarian response in assisted reproductive technologies. Administration of a single dose of gonadotrophin-releasing hormone (GnRH), concomitant with the insertion of a progesterone-loaded controlled internal drug release (CIDR) device, caused regression of gonadotrophin-dependent follicles in all test sheep, with 70% of them initiating a new follicular wave and the remaining showing non-dominant follicles.The present study aimed to set up a short-term protocol for synchronization of follicular wave emergence in sheep, concomitant with estrus synchronization, which would improve ovarian response in assisted reproductive technologies. Administration of a single GnRH dose, concomitant with the insertion of a progesterone-loaded CIDR device, caused regression of gonadotrophin-dependent follicles ≥4 mm in all the GnRH-treated sheep and in around 80% of the controls treated only with CIDR (p < 0.05). Similar percentages of ewes lost all follicles (around 70%) or only the largest one (around 30%) in both groups. Hence, 54.1% and 70% of the sheep lost all large follicles and initiated a new follicular wave in the control and GnRH groups, respectively (p < 0.05). The remaining sheep showed follicles that were still not dependent of luteinizing hormone (LH). So, in fact, all the sheep had non-dominant follicles after treatment. In conclusion, a treatment including GnRH at CIDR insertion would offer a time- and cost-efficient protocol for inducing follicular turnover and synchronizing a new follicular wave at any stage of the estrous cycle.

Using Anti-M&amp;#252;llerian Hormone (AMH) as a Predictor of Ova Production for Bovine Embryo Transfer

The objective of this study was to determine the relationship of anti-Müllerian hormone (AMH) to ova production in various breeds of cattle in an embryo transfer program. Various factors that were evaluated included breed type, age, weight, body condition and flush history as to their influence on total ova recovery. The superovulation regimen called for CIDR (Controlled Internal Drug Release) insertion and a 2 cc injection of Combo (25 mg progesterone and 1.25 mg of estradiol per mL (2 cc IM injection)) on day 0. Day 4, FSH treatments were initiated in both AM and PM with decreasing amounts over the next four days. Day 6, along with FSH, prostaglandin was given in the AM and PM. On Day 7, a final FSH injection and CIDR removal were done in the AM. This resulted in estrus and AI on day 8 and collection of ova on day 15. Results were drawn from analyzing 369 animals; Angus n = 25, Black Brangus n = 43, Red Brangus n = 53, Brahman n = 103, Beefmaster n = 112, and Wagyu n = 33. Age of donors ranged from 1.6 years to 15.4 years at collection with an average age of 7.16 years of age. Analysis of results demonstrated that age clearly had a significant (P 0.05) on ova production. More importantly, we observed the total ova production was significantly (P < 0.05) associated with the AMH concentration (the greater the AMH concentration, the greater number of ova per flush).

PSII-21 Vaginitis incidence and effects on fertility of beef females enrolled on estrus synchronization protocols using a controlled internal drug release (CIDR) device

Abstract Our objectives were to characterize the incidence of vaginitis caused by a controlled internal drug release (CIDR) device and its effects on fertility of beef females enrolled on estrus synchronization followed by timed-artificial insemination (TAI). A total of 1,097 mature cows and 215 heifers from 9 different locations were enrolled in the 7-d CO-Synch + CIDR synchronization protocol. At CIDR insertion, all females were inspected for any previous signs of vaginitis prior to enrollment in the experiment. As evidence of vaginitis, a CIDR score was determined at CIDR removal, and an AI plastic sheath score was also performed at TAI following a 1 to 4 system: 1=clean presenting no secretion; 2=clean presenting clear secretion; 3=presence of purulent secretion; 4=presence of purulent secretion and blood. Pregnancy status was determined by rectal ultrasonography approximately 40 days after TAI. The scores for CIDR and AI plastic sheath did not differ between cows and heifers. Of all females, 6% had a CIDR score of 1, 31% score 2, 56% score 3, and 7% score 4. Plastic sheath score was 1 for 16%, 2 for 62%, 3 for 15%, and 4 for 7% of females. Pregnancy rate to TAI differed between cows and heifers (P &amp;lt; 0.01), among locations (P &amp;lt; 0.001) and ranged from 36 to 66%; however, it was not influenced by CIDR score (P = 0.259) and plastic sheath score (P = 0.785). Pregnancy rate of females by different CIDR scores was 60%, 57%, 52%, and 46% for scores 1, 2, 3, and 4, respectively. Pregnancy rate of females by different AI plastic sheath score was 60%, 55%, 45%, and 48%, for scores 1, 2, 3, and 4, respectively. The presence of vaginitis caused by a CIDR does not influence pregnancy rates of TAI in beef females.

166 Comparison of the 7 and 7 Synch protocol and the 7-day CO-Synch + controlled internal drug release protocol among recipient beef cows in an embryo transfer programme

An experiment was designed to evaluate the effectiveness of the recently developed 7 and 7 Synch protocol to synchronise oestrus and ovulation among recipients before embryo transfer (ET). Postpartum beef cows (n=1358) across 13 locations were assigned to either the 7-day CO-Synch + controlled internal drug release (CIDR) protocol or the 7 and 7 Synch protocol before oestrus detection and subsequent ET. Cows were pre-assigned to balanced treatments within location based on age and days postpartum, and body condition score was recorded at ET. Cows assigned to the 7-day CO-Synch + CIDR protocol were administered gonadotrophin-releasing hormone (GnRH; 100µg of gonadorelin acetate) on Day 0, an intravaginal CIDR insert (1.38g of progesterone) from Day 0 to 7, and prostaglandin F2α (PG; 25mg of dinoprost tromethamine) coincident with CIDR removal on Day 7. Cows assigned to the 7 and 7 Synch protocol were administered PG (25mg of dinoprost tromethamine) coincident with CIDR insertion on Day −7, GnRH (100µg of gonadorelin acetate) on Day 0, and PG (25mg of dinoprost tromethamine) coincident with CIDR removal on Day 7. The 7 and 7 Synch protocol was hypothesised to enhance response to GnRH administration on Day 0 among mixed groups of oestrous cycling and anestrous cows, ultimately resulting in improved oestrous response and synchrony of oestrus before ET. Cows were observed for visible signs of oestrus following oestrus synchronisation, with GnRH (100µg of gonadorelin acetate) administered to cows failing to express oestrus during the detection period. Length of the detection period varied among locations but was consistent across treatments within location. Embryo transfer was performed approximately 7 days after oestrus or GnRH administration. Presence of corpora lutea (CL) was determined via transrectal palpation by a single veterinarian blinded to treatment, and embryos were transferred only to cows with palpable CL. Embryo transfer was performed using fresh or frozen embryos staged and graded according to IETS recommended guidelines, with embryo information recorded for each recipient. Data were analysed using the PROC GLIMMIX procedure of SAS (SAS Institute Inc.). Proportion of cows expressing oestrus was improved (P&amp;lt;0.0001) among cows assigned to the 7 and 7 Synch protocol (86% (529/615) vs. 76% (488/640)). The proportion of recipient females with palpable CL tended to be greater (P=0.07) among cows assigned to the 7 and 7 Synch protocol (82% (478/586) vs. 80% (451/565)). Among cows that expressed oestrus, a greater proportion (P&amp;lt;0.01) had palpable CL following the 7 and 7 Synch protocol (88% (466/529) vs. 86% (418/488)). Consequently, irrespective of embryo type received, the proportion of recipients pregnant to ET was greater (P&amp;lt;0.01) following the 7 and 7 Synch protocol (39%; 263/668) compared with the 7-day CO-Synch + CIDR protocol (33%; 228/690). In summary, the 7 and 7 Synch protocol improved the likelihood of oestrus expression in recipient cows, increased the proportion eligible to receive an embryo, and resulted in greater pregnancy rate to ET.

103 Effects of administration of human chorionic gonadotrophin at Day 5 post-ovulation on development of the original corpus luteum depend on the locational relationship between the original and accessory corpora lutea

In cattle, human chorionic gonadotrophin (hCG) is administered at Day 5 post-ovulation to improve fertility. This treatment can induce ovulation of the first-wave dominant follicle (W1DF), from which an accessory corpus luteum (CL) is generated. In addition, hCG has the effect of promoting CL development. It is possible that the locational relationship between the original and accessary CLs influences the effect of hCG on CL development, because the locational relationship of the CLs affects intraovarian blood flow. The present study aimed to clarify whether the locational relationship between the original and accessory CLs influences the effect of hCG on their development. Cross-bred beef heifers (Holstein×Japanese Black, n=56) were used for the present study. The oestrus cycle was synchronized using oestradiol benzoate (EB) and a controlled internal drug release (CIDR)-based program. Briefly, an administration of EB (2mg) with 9-day CIDR insertion was followed by administration of prostaglandin F2a analogue (PGF2a) on the day of CIDR removal, EB (1mg) 1 day after a PGF2a injection, and GnRH 12h after the second EB injection. At Day 5 post-ovulation, the locational relationship between the original CL and the W1DF was confirmed using transrectal ultrasonography (USG), and two groups were defined: ipsilateral group (IG; n=30), in which the CL and the W1DF are in the same ovary, and contralateral group (CG; n=26), in which the CL and the W1DF are in separate ovaries. Moreover, IG and CG were respectively subdivided into two groups, with or without hCG (1500IU) treatment (IG/hCG, n=15; IG without hCG, n=15, and CG/hCG, n=14; CG without hCG, n=12). The diameter and luteal tissue area (i.e. minus the cavity area) of the original CL and the accessory CL were examined at Days 5, 7, and 14, using USG. Two-way repeated-measures ANOVA was used to compare the diameter and luteal tissue area between IG/hCG and IG without hCG, and between CG/hCG and CG without hCG. In CG, the diameter (P&amp;lt;0.01) and luteal tissue area of the original CL (P&amp;lt;0.001) at Day 7 was increased by receiving hCG, while it did not change in IG. The diameter and luteal tissue area of the original CL at Day 14 were not affected by the administration of hCG in either CG or IG. Moreover, for the accessory CL, no difference of the diameter and luteal tissue area was observed between CG and IG. The present study showed that hCG treatment at Day 5 post-ovulation stimulate the growth of the original CL at Day 7, when the original CL and accessory CL are on contralateral sides. Our results suggest that the effect of administration of the hCG at Day 5 post-ovulation on the original CL development depends on the locational relationship between the original and accessory CL (IG or CG). The function of the CL affects the intrauterine environment for embryonic development. Therefore, it is necessary to investigate the effect of the hCG injection at Day 5 on the function of CL (i.e. plasma P4 concentration) in IG and CG, respectively.

169 Comparison of pregnancy outcomes in dairy heifers artificially inseminated with sexed semen deposited in the uterine horns versus the uterine body

The use of sexed semen (SS) for AI of cattle has resulted in lower pregnancy per timed AI (P/TAI) compared with conventional semen. This has been attributed to lower sperm dose and cell damage during the cell sorting-freezing process. Horn AI is a common practice in equines and canines to improve pregnancy rate when using low sperm doses. The objective was to compare P/TAI and pregnancy loss (PL) in dairy heifers inseminated with SS deposited in the uterine horn (UH) ipsilateral to the ovary containing the preovulatory follicle (POF) versus TAI in the uterine body (UB). This study was performed on two dairy farms in Georgia (A and B). On farm A, 74 Holstein heifers (12 months old) received a 5-day Cosynch + controlled internal drug release (CIDR) protocol including an intravaginal insert (Eazi-Breed CIDR, Zoetis Animal Health) containing 1.38g of progesterone for 5 days and a dose of gonadotrophin-releasing hormone (GnRH) intramuscularly (100µg, 2mL of Factrel, Zoetis Animal Health). At CIDR removal, heifers received a dose of prostaglandin F2α (PGF2α) intramuscularly (25mg, 5mL of Lutalyse, Zoetis Animal Health) and again 24h later; 72h after CIDR removal, heifers received 100µg of GnRH intramuscularly and TAI with frozen-thawed SS. On farm B, 237 Holstein×Jersey heifers (12 months old) received a modified 5-day Cosynch + CIDR. This protocol was similar to that on farm A but did not include GnRH at the time of CIDR insertion or a second dose of PGF2α 24h after CIDR removal. Immediately before TAI, heifers were examined using transrectal ultrasonography (TRUS) to determine on which ovary the POF was present. Each heifer was randomly assigned to TAI using SS in either the UH ipsilateral to the ovary containing the POF (n=150; farm A, n=32; farm B, n=118) or the UB regardless of where the POF was identified (n=161; farm A, n=42; farm B, n=119). Pregnancy was diagnosed 32 days after TAI using TRUS to determine P/TAI. Heifers diagnosed pregnant were re-examined using TRUS at 60 days of gestation to assess PL. Data were analysed using PROC LOGISTIC and the chi-square test of SAS (SAS Institute Inc.). Heifers that received SS in the UH had adequate P/TAI (50.6% (76/150); farm A: 50.0% (16/32); farm B: 50.8% (60/118)), which tended to be numerically greater (P=0.12) than that observed in heifers receiving SS in the UB (43.4% (70/161); farm A: 40.5% (17/42); farm B: 44.5% (53/119)). In addition, PL was not different between groups and was within normal ranges for dairy heifers (10.0 and 9.4% for UH and UB, respectively). In conclusion, TAI of dairy heifers with SS deposited in the UH ipsilateral to the ovary containing the POF resulted in adequate P/TAI, which was 7.2% greater than TAI in the UB. Horn AI with SS might become a valuable tool for optimising reproductive efficiency and genetic selection of dairy herds.

Effect of exogenous progesterone treatment on ovarian steroid hormones and oxidant and antioxidant biomarkers during peak and low breeding seasons in dromedary she-camel.

Background:Research about the effects of progesterone (P4) and the relationship of P4 to oxidative stress has been achieved in ruminants but not enough in camels.Aim:This study evaluated the effect of exogenous P4 hormone using CIDR for 7 days on blood concentrations of steroid hormones and oxidative status of dromedary she-camels during peak and low breeding seasons.Materials and Methods:The present work was conducted on ten dark dromedary she-camels which were synchronized using a controlled internal drug release (CIDR) for 7 days as a reproductive management tool during peak breeding (November-April) and low breeding season (May-October). The blood samples were collected each other day from CIDR insertion until the end of experiment 5 days after the removal of CIDR. Camels were examined for P4, estradiol (E2), and testosterone (T) as well as malondialdehyde (MDA) as indicator of lipid peroxidation and nitric oxide, superoxide dismutase (SOD), and glutathione-S-transferase as antioxidant markers.Results:Results revealed that P4 was higher during peak breeding season than low breeding season. While the levels of P4 increased during CIDR insertion and declined at CIDR removal and thereafter during breeding season, its concentrations declined after CIDR application during the non-breeding season. On the other hand, blood E2 and testosterone levels decreased after CIDR insertion in both high and low breeding seasons with higher serum E2 concentrations during the peak than the low breeding season. MDA concentrations and SOD activities were significantly (p<0.05) high on day 3 after CIDR insertion during the breeding and non-breeding seasons. During both the seasons, GSH levels decreased after CIDR removal in camels. However, MDA was lower during non-breeding season than high breeding season with no seasonal effect on SOD activity.Conclusion:Exogenous P4 treatment through CIDR in dromedary camels could be more efficient during breeding season than non-breeding season, and effects on circulating oxidant/antioxidant biomarkers and their return to normal levels might refer to the adaptation of camels to CIDR by modulating their oxidant and antioxidant levels.

Ovarian follicular and luteal characteristics in Bos indicus-influenced beef cows using prostaglandin F2α with or without GnRH at the onset of the 5-day CO-Synch + controlled internal drug release (CIDR) protocol

A modification of the standard 5-day CO-Synch + CIDR procedure (5-day Bee Synch + CIDR; Bee Synch), developed for use in Bos indicus-influenced cows, utilizes the addition of prostaglandin F2α (PGF) on Day 0 of the protocol to eliminate mature corpora lutea (CL) and fixed-time AI (FTAI) at 66 h. Objectives were to test the hypothesis that elimination of GnRH on Day 0 (GnRH-1) does not impact significantly the synchronized development of a dominant follicle for presumptive FTAI. Seventy-one estrous cycling Brangus and Brahman x Hereford suckled cows were used in two replicates (35–36/replicate). Following stratification, cows were assigned randomly to a 2 × 3 factorial arrangement of treatments involving two truncated (no FTAI or GnRH-2) versions of Bee Synch (Bee Synch It and IIt), each begun 3, 7, and 10 days post-ovulation. Cows in Bee Synch It received 100 μg GnRH (GnRH-1), 25 mg PGF, and a CIDR on Day 0, whereas cows assigned to Bee Synch IIt received the same treatment but without GnRH-1. All cows received 50 mg PGF on Day 5 at CIDR removal. Synchronized new follicular wave emergence (NFWE; days 1–4) was observed in 68.6 and 38.9% of Bee Synch It and IIt, respectively (P = 0.01). This increased to 93.3% and 72.2%, respectively, if days 0–4 were considered. Inclusion of GnRH at CIDR insertion improved synchronized NFWE but size of the largest follicle at 66 h, the normal time of FTAI, did not differ due to treatment or day of the estrous cycle.