PGF2α Treatment Research Articles

Lactating dairy cows managed for second and greater artificial insemination services with the Short-Resynch or Day 25 Resynch program had similar reproductive performance

The objective of this randomized controlled experiment was to evaluate reproductive performance and reproductive physiological outcomes of lactating Holstein cows managed for second and greater artificial insemination (AI) services with the Short-Resynch or Day 25 Resynch program. Cows from 2 commercial farms were randomly assigned after first service to the Short-Resynch (SR; n = 870) or Day 25 Resynch (D25R; n = 917) program in which they remained until 210 d after first service or left the herd. Cows in D25R received GnRH 25 ± 3 d after AI, whereas cows in SR did not. Cows not reinseminated at detected estrus (AIE) by 32 ± 3 d after AI underwent nonpregnancy diagnosis (NPD) through transrectal ultrasonography (TUS). Nonpregnant cows from both treatments with a corpus luteum (CL) ≥15 mm and an ovarian follicle ≥10 mm (hereafter, CL cows) received 2 PGF2α treatments 24 h apart, GnRH 32 h after the second PGF2α, and timed AI 16 to 18 h later. Cows that did not meet the criteria to be included in the CL group (NoCL cows) received a modified Ovsynch protocol with progesterone (P4) supplementation [P4-Ovsynch; GnRH and controlled internal drug-release device (CIDR) in, 7 d later CIDR removal and PGF2α, 24 h later PGF2α, 32 h later GnRH, and 16 to 18 h later timed AI]. In a subgroup of cows, blood samples were collected and TUS conducted at each treatment to evaluate ovarian responses to resynchronization. Binary data were analyzed with logistic regression, continuous data by ANOVA, and time-to-event data by Cox's proportional hazard regression. A greater proportion (mean; 95% CI) of cows were AIE before NPD in the SR (60.5%; 57.0-63.8; n = 3,416) than the D25R (50.1%; 46.5-53.7; n = 3,177) treatment, whereas pregnancy per AI (P/AI) at 32 d for AIE services before NPD was greater for the D25R (41.3%; 38.8-43.8; n = 1,560) than the SR (37.6%; 35.5-39.8; n = 1,961) treatment. At NPD, a greater proportion of cows in the D25R (84.3%; 82.2-86.2) than the SR (77.0%; 74.4-79.4) treatment were considered CL cows. Pregnancy per AI at 32 d was greater for the D25R than the SR treatment for all timed AI services (D25R = 43.0%; 40.2-45.9 vs. SR = 36.8%; 33.8-39.8) and for CL cows (D25R = 42.8%; 39.7-45.9 vs. SR = 33.8%; 30.6-37.2) but did not differ for NoCL cows (D25R = 39.4%; 32.1-47.3 vs. SR = 44.0%; 36.8-51.4). The hazard ratio for time to pregnancy (1.03; 0.93-1.14) and the proportion of cows not pregnant at the end of the observation period (D25R = 5.9%; 4.4-7.8 vs. SR = 6.7%; 5.0-8.7) did not differ between SR and D25R treatments. The GnRH treatment 25 d after AI resulted in more cows with P4 >1 ng/mL (D25R = 80.5%; 75.3-84.9 vs. SR = 63.6%; 57.3-69.4) and smaller follicle diameter at NPD 32 ± 3 d after AI for D25R (16.2 ± 0.4 mm) than for SR (17.5 ± 0.4 mm); however, it did not affect follicle diameter and luteal regression risk (CL cows only) before TAI. We concluded that the use of reproductive management programs including SR and D25R for CL cows and the P4-Ovsynch protocol for NoCL cows resulted in similar hazard of pregnancy and proportion of nonpregnant cows for up to 210 d after first service.

Approaches for elective induction of kidding in the Sudanese Nubian goats

In the Sudan, the husbandry system of goats in urban and peri-urban areas subject them to kid in streets, under vehicles and in dirty environments thus exposing the newly born kids to the risk of predators, crush under vehicles, exposure to diseases and occasionally death due to the unattended difficult birth. Therefore, need to control time of kidding for survivability of kids and future fertility of the dam was the overall objective of this study. In a randomized block design experiment, twenty mid-term pregnant Nubian goats were assigned to four treatment groups namely, control (1), prostaglandin F2α (PGF2α) treatment (2), dexamethasone treatment (3) and cesarean operation (4), with an overall aim of selecting an appropriate tool for elective induction of parturition that preserves life and health and future fertility of does as well as production of viable kids. The hormonal treatments and caesarean operation were performed on day 140 of gestation in all the treatments. The shortest induction time was seen with caesarean section (1.25±0.72 hours) and dexamethasone showed the longest time for induction (57.40±9.21 hours) followed by PGF2α treatment (29.00±1.37 hours). All the treatments resulted to ease of kidding, preserved the reproductive life of does and produced viable kids, except caesarean operation that significantly resulted in delayed placenta expulsion (22.20±2.86 hours) and delayed the time for resumption of ovarian cyclicity (58±5.25 days). In conclusion, the study recommended the use of prostaglandin F2α hormone as a valuable tool for strategic elective induction of kidding in the Sudanese Nubian goats because of its shortest induction time, early placental expulsion and return to ovarian activities.

Prostaglandins effect on matrix metallopeptidases and collagen in mare endometrial fibroblasts

An increasing number of studies have shown that prostaglandins (PGs) exert multiple regulatory actions in the processes associated to tissue remodeling and fibrosis. Extracellular matrix (ECM) turnover is mediated by matrix metallopeptidases (MMPs). The knowledge about the regulation of their expression in mare endometrium is still limited. Thus, the aim of this study was to investigate whether: (i) profibrotic transforming growth factor (TGF)-β1 modulates PG production in equine endometrium; and (ii) PGE2 and PGF2α modulate MMPs, their tissue inhibitors (TIMPs), and collagen 1 (COL1) expression. In experiment 1, the effect of TGF-β1 (5 ng/mL) on PG secretion and PG synthases mRNA transcription, after 24 and 48 h treatment of mare endometrial fibroblast and epithelial cells was investigated using ELISA and qPCR. In experiment 2, the effects of PGE2 and PGF2α in doses 10-7M and 10-8M on secretion and MMP1, 2, 9, 13, TIMP1, 2, and COL1A1 mRNA transcription in mare endometrial fibroblasts were assessed. Transforming growth factor-β1 treatment decreased secretion of PGF2α by endometrial fibroblasts (P < 0.05) and PGF2α and PGE2 by endometrial epithelial cells (P < 0.05). Prostaglandin E2 increased MMP-2 and MMP-9, and decreased MMP-13 secretion by endometrial fibroblasts (P < 0.05). Additionally, PGF2α treatment increased MMP-2, MMP-13 and COL1, but decreased MMP-1 secretion by endometrial fibroblasts (P < 0.05). Prostaglandins may be involved in the processes associated to pathological endometrial remodeling by their effect on MMP expression. The effect of PGF2α on COL1 secretion from fibroblasts suggests its profibrotic role in pathological endometrial remodeling.

Short communication: Economic impact among 7 reproductive programs for lactating dairy cows, including a sensitivity analysis of the cost of hormonal treatments

Although hormonal synchronization programs can improve reproductive efficiency of dairy herds, some farmers question the economics of these programs based on the upfront cost of hormonal treatments as opposed to the economic value of the resulting reproductive performance. Our aim was to compare the economic impact of reproductive management programs that incorporate varying degrees of detection of estrus and timed artificial insemination (AI) in dairy herds with year-round calving in confinement total mixed ration systems. A reproductive economic analysis simulation model was used to compare the economic impact of pairs of reproductive management programs. We simulated sets of scenarios for 2 analyses. In the first analysis, we calculated the economic impact of switching from a Presynch-Ovsynch program to a Double-Ovsynch program that included a second PGF2α treatment during the Breeding-Ovsynch portion of the program (Double-Ovsynch+PGF). In the second analysis, we conducted a break-even analysis in which the cost of hormonal treatments was incrementally increased within various reproductive management programs. Our analyses revealed that a Double-Ovsynch+PGF program, the most intensive program evaluated, was more profitable than other programs compared, including a Presynch-Ovsynch program with 100% timed AI or a Presynch-Ovsynch program that incorporated detection of estrus, despite the higher upfront cost incurred by using more hormonal treatments. This advantage remained until the cost of hormones was increased 5 to 14 times current US market prices and 2 to 6 times current European market prices. The cost of GnRH had a greater impact on net profit gain than the cost of PGF2α. In conclusion, more intensive reproductive programs that use more hormonal treatments but result in substantially increased reproductive performance are more profitable than less intensive programs and remain so even if hormone prices are unusually high.

The presence of CC chemokines and their aberrant role in the porcine corpus luteum.

The process of luteal regression is tightly regulated by the immune system and chemokines-small cytokines responsible mostly for the activation and migration of immune cells. The role of chemokines in porcine corpus luteum (CL) function is still not well understood. The aim of this study was to investigate the expression profile and distribution of CC chemokines in the porcine CL during the natural oestrous cycle and early pregnancy. Additionally, the effect of PGF2α on the expression of selected chemokines and their luteotropic and apoptotic influence on CL cells were studied in vitro. The expression levels of the chemokines CCL2, CCL4, and CCL5 and the chemokine receptor CCR5 were time-dependent (low on Days 8-10 and high on Days 12-14 of the oestrous cycle). Moreover, CCL8 and CCR2 transcript levels were also elevated during the period of luteolysis. The immunolocalization of CCL2, CCL4, CCL5, CCR1, CCR2 and CCR5 was determined using CL sections obtained from cycling and pregnant pigs. The immunofluorescence signals were localized mainly in luteal cells. PGF2α treatment of CL cells caused increased mRNA expression of CCL2 and CCR1. CCL2 treatment alone upregulated the expression of genes BAX, BCL2 and StAR in CL cells in vitro, but additional experiments showed that the chemokines CCL2, CCL4 and CCL5 alone do not cause apoptosis in a mixed population of CL cells. The chemokine CCL4 increased the transcript levels of StAR and HSD3-β1. Additionally, CCL5 led to the inhibition of BAX gene expression. The differential spatiotemporal expression of CCL2, CCL4, CCL5 and CCR5 throughout the oestrous cycle and the direct but aberrant effect of these three chemokines on genes associated with apoptosis and progesterone synthesis indicate the complicated involvement of these factors in the regulation of luteolysis in pigs.

Changes in Prostaglandin-associated Periorbital Syndrome After Switch from Conventional Prostaglandin F2α Treatment to Omidenepag Isopropyl in 11 Consecutive Patients.

We evaluated the recovery of patients with PAPS for whom the treatment regimen switched from conventional prostaglandin F2α analogues to a new selective prostaglandin-EP2 agonist: omidenepag isopropyl. From November 2018 to July 2019, we prospectively evaluated 11 patients who had been using conventional PGF2α drugs. Digital photographs of the patients were taken before the start of omidenepag isopropyl therapy and ~3 and 6 months after. Three independent observers used the photographs to judged recovery according to the 5 signs of PAPS: deepening of the upper eyelid sulcus (DUES), flattening of the lower eyelid bags, upper eyelid ptosis, ciliary hypertrichosis, and periorbital skin hyperpigmentation. The mean age of patients was 61, and 7 patients were female. The original PGF2α drugs were bimatoprost, latanoprost, travoprost, and tafluprost. The mean duration of PGF2α treatment was 65 months. PAPS signs were evaluated in 10 patients after 3 months and in all 11 patients after 6 months: After 3 and 6 months, DUES improved in 3 and 3 patients, respectively; flattening of the lower eyelid bags improved in 1 and 2 patients, respectively; upper eyelid ptosis did not improve in any patients; ciliary hypertrichosis improved in 0 and 2 patients, respectively; and eyelid pigmentation improved in 2 and 8 patients, respectively. The 3 patients who showed improvement in DUES at 6 months had all previously used bimatoprost. Some PAPS signs improved after patients started taking omidenepag isopropyl. Our findings will be useful for patients taking antiglaucoma eye drops.

Artificial lactation by exogenous hormone treatment in non-pregnant sows.

This study aimed to determine if lactation can be induced by exogenous hormonal treatment in non-pregnant sows. In experiment 1, pseudopregnant animals were divided into four groups and given: 1) 5 mg of estradiol dipropionate (EDP) 5 days before (n = 4), 2) 5 mg of EDP 10 days before (n = 3), 3) 10 mg of EDP 5 days before (n = 3) or 4) 10 mg of EDP 10 days (n = 3) before PGF2α treatment. Artificial lactation was induced in seven pseudopregnant sows (53.8%) by exogenous hormonal treatment. There was no significant effect of either an increased EDP dosage or interval from the EDP treatment to PGF2α treatment on the induction rate of artificial lactation. In experiment 2, milk samples were collected from artificial lactating and natural lactating sows (n = 6). IgG and IgA levels in the milk collected from both groups were significantly associated with time during the experimental period. Milk IgG levels 24 h after PGF2α treatment in artificial lactating sows were higher than those in the colostrum of lactating sows. In experiment 3, hormonal profiles in pseudopregnant sows with (n = 3) or without (n = 3) EDP treatment were determined. There was a significant difference in estradiol-17β levels on days 8, 7 and 5 before PGF2α treatment between groups. Progesterone and prolactin concentrations did not differ between groups. The present study revealed for the first time that lactation could be induced by exogenous hormonal treatment in non-pregnant sows and that the milk collected from these sows contained high immunoglobulin levels.

105 Optimization of a five-day fixed-time embryo transfer program in dairy heifers: Use of gonadotrophin-releasing hormone at initiation of the protocol

Optimized fixed-time embryo transfer (FTET) protocols for synchronization of recipients have the potential to improve the overall efficiency and profitability of embryo transfer (ET) programs. The objective of the present study was to evaluate the effect of dose of gonadotrophin-releasing hormone (GnRH) at initiation of a 5-day synchronization protocol for FTET. Holstein heifers (n=2689) at two locations were synchronized using a 5-day CO-Synch protocol as follows: Day 0: CIDR inserted, Day 5: CIDR removed, prostaglandin (PG)F2α treatment (500μg cloprostenol), Day 6: PGF2α treatment, Day 8: GnRH (100μg of gonadorelin). On Day 0, at the time of CIDR insertion, heifers were assigned in a completely randomised design to the following groups: Single (a single dose of GnRH; 100μg of gonadorelin), Double (200μg of gonadorelin) or No GnRH (control). All heifers received an Estrotect patch placed on Day 5 and evaluated for signs of oestrus on Day 8. At location A, heifers were evaluated by ultrasonography 5 days after GnRH to determine presence and size of corpus luteum (CL), whereas at location B presence and location of CL were determined by transrectal palpation at the time of transfer. Heifers with a CL received an embryo 7±1 days after GnRH administration, and pregnancy was determined by ultrasonography 41 and 63 days after GnRH. Data were analysed by generalized linear mixed models. Oestrus expression was greater in heifers that received Single and Double GnRH than in the No GnRH group (P=0.001). Similarly, utilisation rate (number transferred per number treated) was greater for heifers in the Single and Double GnRH group than for those in the No GnRH group (P=0.02). Pregnancy data were analysed for a subset of recipients using data from Day 41 (n=2267) and Day 63 (n=2042). The analysis of fertility outcomes included as covariates the type of embryo (invitro fresh or frozen and invivo fresh or frozen), embryo stage, embryo quality, interval from GnRH to transfer, and oestrus expression. Pregnancies per embryo transfer (P/ET) at Days 41 and 63 were not different between treatment groups (P=0.86), and there was no interaction between type of embryo and treatment (P&amp;gt;0.15). Pregnancy loss between Days 41 and 63 was not different (P=0.49) between treatments groups. In conclusion, the removal of the initial GnRH from a 5-day FTET protocol resulted in a slight but significant reduction in the utilisation rate and the percentage of heifers showing oestrus. However, there was no detrimental effect on fertility. As a result, the overall cost of the FTET program can be reduced by eliminating the need for the initial GnRH treatment without compromising fertility. Table 1.Reproductive performance in recipients receiving different doses of gonadotrophin-releasing hormone (GnRH) at initiation of the synchronization protocol Treatment Oestrus (n) Utilisation rate (n) P/ET1 D41 (n) P/ET D63 (n) Pregnancy loss (n) No GnRH 69.2%B (621/898) 85.0%B (763/898) 41.6% (308/740) 39.9% (268/672) 4.3% (12/280) Single GnRH 76.1%A (685/900) 88.8%A (799/900) 42.7% (329/770) 39.5% (272/689) 6.5% (19/291) Double GnRH 75.3%A (671/891) 88.7%A (790/891) 41.5% (314/757) 38.9% (265/681) 5.4% (15/280) A,BValues with different superscripts within a column differ (P&amp;lt;0.05). 1P/ET=pregnancies per embryo transfer.

101 Treatment with gonadotrophin-releasing hormone on Day 7 or 21 does not reduce pregnancy loss in dairy heifers receiving invitro-produced embryos

Previous research has shown that induction of an accessory corpus luteum (CL) by administration of gonadotrophin-releasing hormone (GnRH) on Day 5 increases circulating progesterone and reduces pregnancy loss between Days 33 and 60 in heifers receiving invitro-produced (IVP) embryos. Therefore, the objective of the present study was to determine whether timing of induction of an accessory CL influenced pregnancy loss in IVP recipients. Holstein heifers (n=1,658) were synchronized using a modified 5-day CIDR CO-Synch protocol. Briefly, heifers received an intravaginal progesterone device (CIDR) on Day −8, Day −3: CIDR removed and first prostaglandin F2α (PGF2α) treatment, Day −2: second PGF2α, and Day 0: GnRH (G1, 100µg of gonadorelin acetate). Oestrus expression was evaluated on Day 0 with the use of an oestrus detection device. Transfer of fresh IVP embryos was performed on Day 7±1 after G1. At the time of transfer, heifers were randomly assigned, in a 2×2 factorial design, to receive GnRH (200µg of gonadorelin acetate) or remain as Control (untreated) at two different times: Day 7 (time of embryo transfer (ET)) or Day 21. Thus, the following groups were formed: Control-Control (n=410); Control-GnRH (n=409); GnRH-Control (n=419); and GnRH-GnRH (n=420). All heifers were evaluated by transrectal ultrasonography to determine number, size, and location of CL on Days 5, 14, 21, 28, 32, and 60 and pregnancy status on Days 28, 32, and 60. Data collected from each heifer included embryo stage and quality, oestrus expression, body condition score, number of transfers, and technician. Pregnancies per embryo transfer (P/ET) and pregnancy loss data were analysed by logistic regression (SAS 9.4). Ovulation to Day 7 treatment was greater (P&amp;lt;0.01) in GnRH treated heifers (70.0%; 585 out of 836) than in untreated Controls (2.7%; 22 of 819). Ovulation to Day 21 treatment was determined only in animals pregnant at Day 28 and was greater (P&amp;lt;0.01) in heifers treated with GnRH (37.6%; 153 of 407) than in untreated controls (1.0%; 4 of 390). There was no effect of Day 7 treatment (P&amp;gt;0.68) or Day 21 treatment (P&amp;gt;0.18), nor a Day 7×Day 21 treatment interaction (P&amp;gt;0.48) on P/ET at Day 32 or 60 (Table 1). Treatment with GnRH on Day 7 or 21 did not alter pregnancy loss between Days 32 and 60 (P&amp;gt;0.10). Heifers with an accessory CL present at Day 32 (11.7%; 41 of 350) had similar (P=0.55) pregnancy loss compared with heifers with no accessory CL (14.4%; 54 of 375). The number of CL present on Day 32 did not affect (P=0.23) pregnancy loss; however, heifers with 3 CL (4.9%; 3 of 61) tended (P&amp;lt;0.10) to have reduced pregnancy loss compared with heifers with 1 CL (14.4%; 54 of 375) or 2 CL (13.2%; 38 of 289). In conclusion, treatment with GnRH on Day 7 or 21 induced an accessory CL; however, it did not affect P/ET on Days 32 or 60 and pregnancy loss. Table 1.Pregnancies per embryo transfer (P/ET) and pregnancy loss in embryo recipients based on timing of treatment with gonadotrophin-releasing hormone (GnRH) Treatment P/ET Day 32% (n) P/ET Day 60% (n) Pregnancy loss% (n) Day 7 Day 21 Control Control 42.4 (410) 36.1 (410) 15.0 (174) GnRH 46.0 (409) 40.7 (409) 11.7 (188) GnRH Control 43.7 (419) 36.8 (419) 15.9 (183) P-value GnRH 43.1 (420) 38.8 (420) 10.0 (181) Day 7 treatment 0.68 0.72 0.96 Day 21 treatment 0.51 0.18 0.11 Interaction 0.48 0.66 0.71

Conception Rate of 11 Months Old Dairy Heifer Following Artificial Insemination with Natural Estrus and PGF2α Treatment

The aim of this study was to evaluate the conception rate of 11-months old dairy heifer following artificial insemination with natural estrus or treated with PGF2α at PT. Ultra Peternakan Bandung Selatan. A case study was applied in this study involving all data of 700 records for date of birth, body weight and reproduction status. Sample was selected according the complete records with criteria of age was 11±3 months, body weight >300kg, having normal reproduction organs detected by rectal palpation. The results showed that from observation of selected 300 samples out of 700 heifers, 25 heifers of them were natural estrus (Control), 50 estrus after single PGF2α injection (PG), 95 following single PGF2α and left to normal estrus after 21 days (PG-N), 50 after double PGF2α (2PG), and the rest of 80 heifers showed estrus following double PGF2α – Natural estrus (2PG-N) with the conception rate (CR) of 17/25(68%), 44/50(88%), 42/50(84%), for the respective groups. None of heifers in PG-N and 2PG-N groups became pregnant after first insemination. The body weight (BW) was classified into Low (336-347kg), Medium (348-359kg) and High (360-372kg). The total conception rate was 34%. The CR for Low, Medium and High BW were 41%, 32% and 31%, respectively. The conclusion, the 11-months old heifer was possible to become normal pregnant following insemination without and with PGF2α injection when reached body weight over 300 kg. To ensure the higher number animal exhibiting estrus, double PGF2α injections should be applied.

Short communication: Reproduction outcomes in dairy heifers following a 14-d progesterone insert presynchronization protocol

The objectives were to evaluate pregnancy per artificial insemination (AI), days to first AI, and proportion pregnant within 7 d of AI eligibility in dairy heifers subjected to presynchronization compared with dairy heifers not presynchronized. Thirty days before AI eligibility, Holstein heifers were assigned randomly to 1 of 3 groups: 14-d controlled internal drug release (CIDR; containing progesterone) presynchronization, PGF2α presynchronization, or control (no presynchronization). Heifers in the 14-d CIDR presynchronization treatment (n = 119) received a CIDR on d -30, which was removed on d -16, followed by an injection of PGF2α upon entry to the breeding program (d 0). Heifers in the PGF2α presynchronization treatment (n = 118) received an injection of PGF2α on d -11 and d 0. Control heifers (n = 121) were not presynchronized and received an injection of PGF2α on d 0. All heifers received tail paint on d 0 to facilitate once-daily detection of estrus (based on paint removal). Heifers detected in estrus received AI with conventional semen on the same morning as detected estrus. Generalized linear mixed models were used to assess mean treatment differences. Following PGF2α treatment on d 0, more heifers were detected in estrus in the first 7 d after eligibility in the 14-d CIDR group (95.8%) compared with the PGF2α (74.6%) and control (66.9%) groups. Days to first AI differed between treatments (14-d CIDR = 3.6 d vs. PGF2α = 5.0 d vs. control = 6.8 d). Pregnancy per AI for first AI within 7 d of eligibility was 71.9% (14-d CIDR), 58.0% (PGF2α), and 61.7% (control), and differed between 14-d CIDR and PGF2α heifers. Presynchronization with a 14-d CIDR increased the proportion of heifers pregnant in the first 7 d of eligibility (14-d CIDR = 68.9% vs. PGF2α = 43.2% vs. control = 41.3%). Projected days on feed (d 0 to projected calving date) were 295 (14-d CIDR), 302 (PGF2α), and 305 (control), and were different between the 14-d CIDR and control heifers. The potential economic benefit to the producer was $15.85 per heifer presynchronized with a 14-d CIDR protocol compared with the control group. Treatment of dairy heifers with a 14-d CIDR effectively presynchronized estrus, resulting in a greater proportion detected in estrus, reduced days to first AI, and an increased proportion of heifers pregnant within the first 7 d after breeding eligibility compared with heifers presynchronized with a single PGF2α injection and control heifers.

Investigating Post-partum Ovarian Cyclicity Following Various Treatments in Dairy Cows

Abstract The present study envisages the effect of PGF2α and antibiotic treatment on ovarian cyclic activity and regression of corpus luteum verum in post-partum dairy cows. Cows were divided into three treatment (PG8, PG25, antibiotic) and a control group. Ovarian activity was studied by examining follicular dynamics upto 42 days post-partum in which diameter of dominant follicle before first ovulation, the number of days to first ovulation and complete regression of corpus luteum verum were evaluated. Body condition score was recorded for all the cows in different groups. Also, ovulation on ovary ipsilateral or contralateral to previous gravid uterine horn was noted. On transrectal ultrasonography at a 3-day interval, dominant follicle diameter prior to ovulation was significantly higher (p&lt;0.01) in PG8 group. The mean time required for complete regression of CL verum was not significantly (p&gt;0.05) lower in PG8 group i.e. 24.33±1.48 days in comparison to PG25, antibiotic and control group (26.67±1.48, 29.00±1.81and 27.60±1.40 days post-partum, respectively). A subsequent ovarian activity was affected as 70.83 and 66.33% Ist and IInd ovulations occurred on the ovary contralateral to corpus luteum verum. In conclusion, contralateral ovary was more active in terms of ovulation whereas presence of corpus luteum verum had no effect on post-partum ovarian cyclic activity.

200 Improving efficiency of embryo transfer (ET) programs by optimizing fertility and management of recipients

Abstract Multiple experiments were performed to optimize efficiency and fertility in recipients of fresh in vitro produced (IVP) embryos. In experiment 1, heifers (n = 520) were synchronized and received an embryo on d 6–8 after estrus or 6–8 d after GnRH in a fixed time ET (FTET) program using modified 5-d CIDR-Synch protocol (d-8: CIDR inserted; d-3: CIDR removed and PGF2α treatment; d-2: second PGF2α; d0: GnRH to induce ovulation). Pregnancy per ET (P/ET) at d 32 and d 60 were similar but pregnancy per treated potential recipient (efficiency of recipient utilization) was greater for FTET than estrus (+49.7%). Subsequent experiments sought to optimize FTET protocol by analyzing whether CIDRs could be used multiple times (up to 4 uses similar P/ET) and whether multiple PGF2α treatments were needed at end of program (no difference when no GnRH given at start of protocol). Thus, a simple, inexpensive FTET program has similar fertility as ET after estrus but is more efficient at recipient utilization. A large retrospective analysis (n = 12,569 ET) was performed using FTET program. Embryo stage and quality were major embryo factors impacting P/ET. Transfer of d 7 fresh embryo to d 7 or d 8 recipient was better than d 6 (+24.4%). Two experiments (GnRH or CIDR treatment) evaluated increasing circulating P4. In GnRH experiment, heifers (n = 1,562) on d5 received GnRH (200 μg) or Control (untreated). On D12, P4 was greater (P &lt; 0.001) in GnRH-treated (7.2 ± 0.1ng/ml) vs Controls (6.0 ± 0.1ng/ml). There was greater P/ET at D33 and D60 of pregnancy for Stage 7 than 6 embryos. Treatment with GnRH did not alter P/ET but decreased pregnancy loss between D33 and D60 in heifers receiving Stage 7 embryos (11.6 vs 27.6% in recipients with accessory CL on d 33). In CIDR experiment, treatment with 2 CIDRs (from d 13; one new CIDR each 7 d) elevated circulating P4 and tended to decrease pregnancy loss (d 27 to 62; 25.9 vs 11.9%) and increase P/ET (40.4 vs 53.6% on d 62). Thus, elevating P4 decreased pregnancy loss during FTET program using fresh IVP embryos.

201 Development of fertility programs to achieve high 21-day pregnancy rates in high-producing dairy cows

Abstract The initial impact of the original Ovsynch protocol on 21-d pregnancy rates in U.S. dairy herds was to increase AI service rates; however, a deeper understanding of the physiology underlying the Ovsynch protocol has allowed for modifications to the original protocol that dramatically increase in pregnancies per artificial insemination (P/AI). A key factor affecting P/AI to timed AI is the response to each hormonal treatment of the Ovsynch protocol. Cows that ovulate to the first GnRH treatment of the Ovsynch protocol (G1) have more P/AI than cows that fail to ovulate. The association between progesterone (P4) concentrations at each treatment during the Ovsynch protocol and P/AI was analyzed based on data from 7,792 cows across 14 experiments. Cows with P4 concentrations from 0.5 to 6.0 ng/mL at G1, &gt;1.0 ng/mL at PGF2α, and &lt;0.4 ng/mL at the last GnRH treatment had the most P/AI. Presynchronization strategies that combine GnRH and PGF2α induce ovulation in anovular cows and optimize P4 concentrations at G1 and the PGF2α treatments of the Ovsynch protocol to increase P/AI. A subgroup of cows, however, fail to undergo complete luteal regression after the PGF2α treatment of the Ovsynch protocol, particularly multiparous cows that initiate G1 in a low P4 environment and cows with a CL that has not yet acquired luteolytic capacity. Addition of a second PGF2α treatment 24 h after the first in the Ovsynch protocol increases the percentage of cows with complete luteal regression thereby increasing P/AI. The key to increasing P/AI to Resynch protocols is to segregate nonpregnant cows based on the presence or absence of a CL and to treat cows without a CL with exogenous P4 during the Resynch protocol. Adoption of fertility programs developed using these concepts have yielded annualized 21-d pregnancy rates that exceed 30% in healthy, high-producing dairy herds.

Effect of Utilization of Single or Double Prostaglandin Administration Within an Ovsynch Fixed-Time Artificial Insemination Protocol During Summer Season in Dairy Cows

Abstract This study investigated the fertility of dairy cows during summer season after treatment with a single or double PGF2α in a progesterone (P4)-based Ovsynch protocol for fixed-time artificial insemination (FTAI). The data were compared to a treatment effectuated during winter season. Two groups of 60 dairy cows each were randomly assigned on day 60 post-partum to single PGF2α or double PGF2α group. At removal of the P4 treatment the single PGF2α group received a single dose and the double PGF2α group received two doses of PGF2α at 24 hours apart. In each group, 30 cows were treated during the summer (June, July and August) and 30 cows during the winter (December, January and February) season. During summer season a double PGF2α dose did not influence pregnancy rate at FTAI but improved cumulative pregnancy rate 60 days after FTAI (43% vs 69% for single PGF2α and double PGF2α administration, respectively; P&lt;0.05). During winter season the single or double PGF2α administration did not modify PR or cumulative PR. In conclusion, during summer the utilization of a double instead of single PGF2α treatment into a P4-based Ovsynch-FTAI protocol did not increase pregnancy rate at FTAI but improved cumulative pregnancy rate.

Postovulatory treatment with GnRH on day 5 reduces pregnancy loss in recipients receiving an in vitro produced expanded blastocyst

The present study tested the hypothesis that administration of GnRH on day 5 of the estrous cycle in embryo transfer (ET) recipients would increase progesterone (P4) concentrations, embryo size, and improve fertility. Holstein and cross-bred Holstein heifers (n = 1562) were synchronized using a modified 5-day CIDR-Synch protocol as follows (All AM treatments): D-8, CIDR inserted; D-3, CIDR removed and PGF2α (500 μg cloprostenol) treatment; D-2, second PGF2α; D0, GnRH (G1, 100 μg gonadorelin acetate) to induce ovulation. On D5 in the afternoon, heifers were assigned in a completely randomized design to one of two treatments: Control (untreated) or GnRH (200 μg). Transfer of day 7 fresh IVP embryos was performed between D6 and D8 after G1. Data collected from each heifer included: embryo stage and quality, body condition score, technician performing ET, interval from G1 to ET, and number of previous transfers. All heifers were evaluated by transrectal ultrasonography on D5, D33, and D60 and a subset of heifers was scanned on D12 (n = 718; to determine ovulation to treatment) and another subset on D33 (n = 295; 16 s video to determine embryo and amniotic vesicle size). Serum P4 was determined from a subset of heifers on D12 (n = 467) and on D21 (n = 837) and pregnancy specific protein B (PSPB) on D28 (n = 843). Pregnancies per ET (P/ET) were analyzed by logistic regression and continuous outcomes by ANOVA. Ovulation to D5 GnRH, defined by the presence of an accessory CL on D12, was 83.9% (302/360) in GnRH-treated heifers vs. 3.3% (12/358) in Controls (P < 0.001). On D12, P4 was greater (P < 0.001) in GnRH-treated heifers (7.2 ± 0.1 ng/ml) vs Controls (6.0 ± 0.1 ng/ml). There was greater P/ET at D33 and D60 of pregnancy for Stage 7 than Stage 6 embryos. Treatment with GnRH did not alter P/ET with either embryo stage but decreased pregnancy loss between D33 and D60 in heifers receiving Stage 7 embryos. Presence of an accessory CL at the D33 pregnancy diagnosis was associated with a larger reduction in pregnancy loss from D33 to D60 in recipients of Stage 7 embryos (11.6 vs 27.6%). Although there was no GnRH effect on embryo size, the presence of an accessory CL was associated (P < 0.05) with larger amniotic vesicle volume in recipients of Stage 7 embryos. In addition, greater PSPB was linked to greater amniotic vesicle volume (P = 0.01) and to reduced pregnancy loss (P < 0.0001). In conclusion, treatment with GnRH on D5 caused ovulation and formation of an accessory CL, increased circulating P4, and reduced pregnancy loss in heifers receiving a Stage 7 but not a Stage 6 IVP embryo.

Estrous characteristics and reproductive outcomes of Holstein heifers treated with 2 prostaglandin formulations and detected in estrus by an automated estrous detection or mounting device

Dinoprost tromethamine (DIN), a molecule similar to endogenous PGF2α, has a half-life of approximately 9 min. Cloprostenol sodium (CLO), a synthetic analog of PGF2α, has a half-life of approximately 3 h. We hypothesized that treatment of Holstein heifers with CLO would improve estrous detection rate, estrous characteristics, service rate, and overall reproductive performance compared with DIN. Currently in the United States, heifers are largely inseminated based on signs of estrus, which is detected visually or with the aid of mounting detection devices (MD). Automated estrous detection devices (AED) are becoming more accessible to producers, but it is not clear whether they present advantages in the reproductive management of heifers. Therefore, we hypothesized that the use of an AED would improve service and pregnancy rates compared with detection of estrus with the aid of a MD. Holstein heifers (n = 1,019) were enrolled in the experiment at 10 to 11 mo of age, when they were fitted with a Heatime HR LD System (SCR Ltd., Netanya, Israel). At 12 mo of age, we paired heifers according to estrous cycle phase and randomly assigned them to treatments in a 2 × 2 design: PGF2α formulation (CLO vs. DIN) and estrous detection treatment (AED vs. MD). Heifers in the AED treatment were detected in estrus only by the Heatime HR LD System, whereas heifers in the MD treatment were detected in estrus only by the Kamar Heatmount Detector (Kamar Products Inc., Zionsville, IN). Treatments with the same PGF2α formulations were repeated 14 d after the first treatment if heifers had not been detected in estrus. A sub-group of heifers had blood sampled on the day of PGF2α treatment and within 24 h of onset of estrus to determine progesterone and estradiol concentrations. Treatment with CLO reduced the progesterone concentration within 24 h of onset of estrus compared with DIN (0.04 ± 0.01 vs. 0.11 ± 0.01 ng/mL). Among heifers in mid diestrus on the day of PGF2α treatment, CLO reduced the interval to estrus compared with DIN (72.0 ± 2.2 vs. 82.4 ± 2.4 h). Prostaglandin F2α formulation and estrous detection treatment did not affect pregnancy to the first service. The interval between the first and second services tended to be reduced for the AED treatment compared with the MD treatment (24.4 ± 0.5 vs. 25.7 ± 0.6 d). Prostaglandin F2α formulation and estrous detection treatment did not affect the hazard of pregnancy. Although CLO treatment may shorten the interval to estrus in heifers at mid diestrus compared with DIN, PGF2α formulation did not affect reproductive performance. In the current experiment, no advantages in reproductive performance were observed when estrous detection was based on an AED compared with a MD.

Genomic merit for reproductive traits. II: Physiological responses of Holstein heifers

Fertility traits were recently added to the evaluation of genetic merit, allowing for the selection of Holstein cattle with improved reproductive performance. In the current study, we investigated the associations among genomic merit for daughter pregnancy rate (GDPR) and heifer conception rate (GHCR) and physiological responses during proestrus and diestrus. Holstein heifers (n = 99) were classified based on GDPR [high = 3.26 ± 0.76 (1.6 to 5.3), n = 48; low = -0.17 ± 0.75 (-1.8 to 1.0), n = 51] and GHCR [high = 2.75 ± 0.77 (1.5 to 5.5), n = 49; low = 0.06 ± 0.67 (-2.1 to 1.2), n = 50]. Heifers were fitted with an automated estrous detection device, were treated with PGF2α for synchronization of estrus, and received either artificial insemination or embryo transfer at detected estrus. Blood was sampled at the time of PGF2α treatment, within 24 h of the onset of estrus (d 0), and on d 7, 14, 19 ± 2, 28, and 35. Blood samples from all heifers were analyzed for concentrations of estradiol (d 0) and progesterone (on the day of PGF2α treatment and d 0, 7, and 14). Blood samples from heifers pregnant on d 38 ± 3 were analyzed for concentrations of progesterone (d 0, 7, 14, 19 ± 2, 28, and 35), pregnancy-specific protein B (d 19 ± 2, 28, and 35), and insulin-like growth factor 1 (d 0, 7, 14, 19 ± 2, 28, and 35). Expression of mRNA for interferon-stimulated gene 15 in peripheral leukocytes isolated from blood collected on d 19 ± 2 was determined. Ovaries were scanned by ultrasound daily from d 0 to 4 or until ovulation was detected. Heifers with low GHCR tended to be less likely to be detected in estrus (78.0 vs. 91.8%). Estradiol concentration on d 0 was greater for heifers with high GDPR (4.53 ± 0.23 vs. 3.79 ± 0.23 pg/mL). The ovulatory follicle was larger for heifers with high GDPR (16.28 ± 0.33 vs. 14.55 ± 0.35 mm), whereas heifers with high GHCR tended to have smaller ovulatory follicles (15.00 ± 0.31 vs. 15.83 ± 0.37 mm). Heifers with high GDPR tended to be more likely to ovulate within 96 h of the onset of estrus (90.7 vs. 75.0%). Among heifers pregnant on d 38 ± 3, GDPR and GHCR were not associated with mRNA expression for interferon-stimulated gene 15. Heifers with high GDPR had greater concentration of pregnancy-specific protein B from d 28 to 35 (3.03 ± 0.15 vs. 2.48 ± 0.1 ng/mL). Heifers with high GHCR tended to have greater insulin-like growth factor 1 concentration from d 7 to 35 (108.0 ± 3.2 vs. 97.7 ± 4.2 ng/mL). Our results suggest that selection for Holstein cattle for GDPR may have positive effects on reproductive performance through changes in ovarian follicle development and steroidogenesis. Although selection of Holstein cattle for GHCR may negatively affect estrous expression by affecting ovarian follicle growth, selection for GHCR may improve reproductive performance by altering the somatotropic axis.

Genomic merit for reproductive traits. I: Estrous characteristics and fertility in Holstein heifers

Genetic selection of dairy cattle in the United States has included reproductive traits (daughter pregnancy rate, DPR; heifer conception rate, HCR), which is believed to have partly contributed to halting the decline in reproductive performance. The objectives of the current study were to evaluate the association among genomic merit for DPR (GDPR) and HCR (GHCR) with estrous characteristics measured by an automated device. Holstein heifers (n = 1,005) were genotyped at 2 mo of age and were classified into quartiles (Q1 = lowest, Q4 = highest) according to the GDPR and GHCR values of the study population. At 10 to 11 mo of age, heifers were fitted with a collar that recorded activity and rumination and determined the occurrence of estrus according to changes in activity and rumination compared with the individual's baseline values. Estrous characteristics of spontaneous estruses (SPE) and PGF2α-synchronized estruses (PGSE) were recorded. Heifers had their estrous cycle synchronized with PGF2α and following detection of estrus received either artificial insemination or embryo transfer according to the herd's genetic selection program. Heifers in Q2 (17.7 ± 0.3 h) of GHCR tended to have longer SPE than heifers in Q4 (16.7 ± 0.3 h). The interaction between GDPR and GHCR was associated with the likelihood of activity peak (0 = no estrus, 100 = maximum activity) ≥80 at SPE because, among heifers in Q3 and Q4 of GHCR, those in Q1 of GDPR were less likely to have an activity peak ≥80. Heifers in Q1 and Q2 of GDPR had reduced hazard of estrus within 7 d of the first PGF2α treatment compared with heifers in Q4 of GDPR. Heifers in Q1 (16.1 ± 0.4 h) of GDPR had shorter PGSE than heifers in Q2 (17.6 ± 0.4 h) and Q4 (17.4 ± 0.4 h) and tended to have shorter PGSE than heifers in Q3 (17.4 ± 0.4 h). Rumination nadir on the day of PGSE was greater for heifers in Q1 (-30.1 ± 0.9 min/d) of GDPR compared with heifers in Q4 (-33.7 ± 0.9 min/d). Among heifers receiving only artificial insemination, those in Q1 of GHCR (adjusted hazard ratio = 0.65; 95% confidence interval = 0.48-0.88) became pregnant at a slower rate than heifers in Q4. Genomic merit for HCR was negatively associated with SPE but tended to be positively associated with hazard of pregnancy, whereas GDPR was positively associated with PGSE and hazard of estrus. Selection of dairy cattle for DPR and HCR may improve reproductive performance through different pathways, namely estrous characteristics and pregnancy establishment.

Profitability of dairy cows submitted to the first service with the Presynch-Ovsynch or Double-Ovsynch protocol and different duration of the voluntary waiting period

The objective of this study was to compare cash flow and parameters of economic performance for dairy cows submitted to the first service using a combination of insemination at detected estrus and timed AI (TAI) in cows synchronized with the Presynch-Ovsynch (PSOv) protocol versus all TAI after synchronization of ovulation with the Double-Ovsynch (DO) protocol with different durations of the voluntary waiting period. A secondary objective was to calculate the variation in cash flow under different input pricing scenarios through stochastic Monte Carlo simulation. Lactating Holstein cows from a commercial dairy farm were randomly assigned to 3 first-service management programs. Cows in the PSOv treatment (n = 450) received first service through a combination of insemination at detected estrus after a voluntary waiting period of 50 d in milk (DIM; i.e., after second PGF2α treatment of the protocol) and TAI at 72 ± 3 DIM. Cows in the DO60 (n = 458) and DO88 (n = 462) treatments received first service by TAI at 60 ± 3 and 88 ± 3 DIM, respectively. Individual cow cash flow was calculated for the calving interval after enrollment and for an 18-mo period after calving. Cash flow was the aggregation of daily income over feed cost, replacement cost, calf value, recombinant bovine somatotropin treatment cost, reproductive cost, and other operating expenses. All analyses were conducted separately for primiparous and multiparous cows. Continuous, binomial, and time to event outcomes were analyzed using ANOVA, logistic regression, and Cox's proportional hazard regression in SAS (SAS Institute Inc., Cary, NC). Treatments affected the dynamics of pregnancy creation, which affected time to pregnancy during lactation. As a result, we observed differences in the proportion of nonpregnant cows at the end of lactation, herd exit dynamics, lactation length, calving interval, and proportion of cows that calved again. Some of these effects varied by parity, affecting the direction and magnitude of treatment differences within parity group. For primiparous cows, maximum cash flow differences per slot for the 18-mo period were in the range of $26 (PSOv > DO60) to $29 (DO88 > DO60) but did not differ statistically. For multiparous cows, maximum cash flow differences per slot for the 18-mo period were in the range of $122 (PSOv > DO88) to $155 (DO60 > DO88) but did not differ statistically. Despite the substantial differences in cash flow (in particular for multiparous cows) caused by the effect of treatments on reproductive performance, herd exit dynamics, and calving interval, large variability in overall cash flow among individual cows and compensation between multiple outcomes resulted in lack of statistical differences in cash flow. Outcomes from the stochastic analysis indicated that similar trends for differences between treatments would be observed under varying scenarios for economic input values. In conclusion, we did not detect statistically significant cash flow differences between the PSOv, DO60, and DO88 treatments, but numerical trends and stochastic simulation indicated that the DO88 and PSOv treatments were more economically favorable than the DO60 treatment for primiparous cows. For multiparous cows, the DO60 and PSOv treatments were more economically favorable than the DO88 treatment.