Serum progesterone levels in post-partum dairy cows after repeated application of the prostaglandin F2 alpha analogue D (+) cloprostenol sodium

Preovulatory serum estradiol concentration is positively associated with oocyte ATP and follicular fluid metabolite abundance in lactating beef cattle

Cattle induced to ovulate a small, physiologically immature preovulatory follicle had reduced oocyte developmental competence that resulted in decreased embryo cleavage and day 7 embryo quality compared with animals induced to ovulate a more advanced follicle. RNA-sequencing was performed on oocytes and their corresponding cumulus cells approximately 23 h after gonadotropin-releasing hormone (GnRH) administration to induce the preovulatory gonadotropin surge suggested reduced capacity for glucose metabolism and oxidative phosphorylation in the cumulus cells and oocytes from follicles ≤11.7 mm, respectively. We hypothesized that induced ovulation of a small, physiologically immature preovulatory follicle results in a suboptimal follicular microenvironment and reduced oocyte metabolic capacity. We performed a study with the objective to determine the impact of preovulatory follicle diameter and serum estradiol concentration at GnRH administration on oocyte metabolic competence and follicular fluid metabolome profiles. We synchronized the development of a preovulatory follicle and collected the follicle contents via transvaginal aspiration approximately 19 h after GnRH administration in lactating beef cows (n = 319). We determined ATP levels and mitochondrial DNA (mtDNA) copy number in 110 oocytes and performed ultra-high-performance liquid chromatography–high resolution mass spectrometry metabolomic studies on 45 follicular fluid samples. Intraoocyte ATP and the amount of ATP produced per mtDNA copy number were associated with serum estradiol concentration at GnRH and time from GnRH administration to follicle aspiration (P < 0.05). mtDNA copy number was not related to follicle diameter at GnRH, serum estradiol concentration at GnRH, or any potential covariates (P > 0.10). We detected 90 metabolites in the aspirated follicular fluid. We identified 22 metabolites associated with serum estradiol concentration at GnRH and 63 metabolites associated with follicular fluid progesterone concentration at the time of follicle aspiration (FDR < 0.10). Pathway enrichment analysis of significant metabolites suggested altered proteinogenesis, citric acid cycle, and pyrimidine metabolism in follicles of reduced estrogenic capacity pre-gonadotropin surge or reduced progesterone production by the time of follicle aspiration.

Uterine Involution and Ovarian Activity in Postpartum Holstein Dairy Cows. A Review

Following parturition in the cow, there is a significant period of sexual quiescence of variable length. This period of reproductive quiescence was found to be longer in suckling or intensively milked animals.This acyclic period is generally considered as the postpartum anoestrous period. The postpartum period constitutes an important period in the reproductive life of dairy cows because of its enormous influence upon subsequent fertility. The entire postpartum period, puerperium, is defined as the period from parturition until the genital organs return to its normal physiological and histological condition, as in normal non-gravid state. They added that any extension of the puerperium in cows might have a detrimental effect on the reproductive performance of the individual animal. Thus, the main determinant of this period is essentially dependent on the resumption of normal ovarian cycles, the manifestation of estrus behaviour and conception following insemination.

Oestrus synchronisation in postpartum dairy cows using repetitive prostaglandin doses: Comparison between D-cloprostenol and dinoprost

This trial evaluated the reproductive performance in an early routine oestrus induction programme using two different PGF2α preparations in dairy cattle. D-cloprostenol sodium (n = 192; Group A) or dinoprost (n = 187; Group B) was administered between days 35 and 42 post partum. Also, a group of non-treated cows (n = 135; Group C) was included as control. Pedometers were used to detect oestrus, and also secondary oestrous signs and vaginal mucus quality were assessed prior to artificial insemination (AI). When oestrus was not detected for 14 days after PGF2α administration, the treatment was repeated, up to a maximum of three times. There were no differences between the study groups in oestrus detection (A = 73.48%, B = 73.01%, C = 79.26%; P = 0.428), good mucus quality (A = 96.45%, B = 91.30%, C = 93.45%; P = 0.203) and the presence of mounting lesions (A = 98.58, B = 94.93%, C = 98.13; P = 0.414). First-service pregnancy rates were 19.78%, 15.64% and 32.03% in Groups A, B and C, respectively (P = 0.003). There were no inter-group differences for the interval from parturition to first AI. However, a significantly shorter interval from parturition to conception (92.17 days, 99.45 days, 118.93 days; P = 0.002) and significantly less services per conception (2.12, 2.18, 2.66; P = 0.003) were observed in Groups A and B in comparison with Group C. The use of PGF2α resulted in better fertility in a repetitive, routine postpartum programme, although no differences between Dcloprostenol and dinoprost were detected.

Accurate ultrasonographic prediction of progesterone concentrations greater than 1 ng/ml in Holstein lactating dairy cows

To develop an ultrasonographic assay for determining plasma progesterone concentration (P4 ) as < 1 ng/ml or ≥ 1 ng/ml, the corpus luteum (CL) area and P4 were measured in 1094 multiparous Holstein cows. The area-measuring function and frozen images were used to outline and measure CL imaged via ultrasonography, and CL area was estimated as a polygon of a continuation straight line. A significant correlation was found between CL area and P4 (p < 0.001), and this analysis resulted in the following correlation equation: y = -0.35 + 1.02x (r = 0.81). According to the correlation equation, a CL area of 1.3 cm(2) indicated a P4 of 1 ng/ml. Based on this relationship, each animal was categorized into one of six groups, groups differed based on CL area, and the area ranges were as follows: < 1.3 cm(2) (Group A), 1.3-2.2 cm(2) (Group B), 2.3-3.2 cm(2) (Group C), 3.3-4.2 cm(2) (Group D), 4.3-5.2 cm(2) (Group E) and > 5.2 cm(2) (Group F). For each group, the proportion of cows whose P4 was 1 ng/ml or more was 1.5% in Group A, 83.3% in Group B, 76.6% in Group C, 96.6% in Group D, 99.2% in Group E and 100% in Group F. There was a significant difference between Group A and the other five groups, and between Groups B or C and Groups D, E or F (p < 0.005). These results indicate that a functional CL does not exist when the CL area is less than 1.3 cm(2) and that it exists when the CL area is 3.3 cm(2) or more.

Temporal analysis of prostaglandin F2α receptor, caspase 3, and cyclooxygenase 2 messenger RNA expression and prostaglandin F2α receptor and cyclooxygenase 2 protein expression in endometrial tissue from multiparous Nelore (Bos taurus indicus) cows treated with cloprostenol sodium during puerperium

The use of cloprostenol sodium in puerperium is questionable, as both favorable and unfavorable responses during the uterine involution process have been reported in the literature. This study is based on the hypothesis that cloprostenol sodium promotes modifications in the prostaglandin F2α receptor (FP), caspase 3 (CASP-3), and cyclooxygenase 2 (COX-2) mRNA expression that may favor the process of postpartum uterine involution in multiparous Nelore (Bos taurus indicus) females. Additionally, we aimed to describe the presence and immunolocalization of the FP and COX-2 protein in endometrial tissue at different postpartum time points in these females. Multiparous Nelore cows (n = 24) were treated with cloprostenol sodium (n = 12) or saline solution (n = 12) on postpartum Days 1 and 4 (Day 0 = birth), and endometrial biopsies were performed with a Yomann biopsy instrument and collected on Days 1, 7, 14, 28, and 42 postpartum. The mRNA expression from samples on the Days 1, 7, 14, 28, and 42 and the protein expression from samples on the Days 1, 14, 28, and 42 were then analyzed. The treated cows had altered FP and CASP-3 mRNA expression, and FP and COX-2 protein were observed in the endometrial surface epithelium, the stroma, and the glandular epithelium, with cytoplasmic immunolocalization. Although we attribute the change in CASP-3 mRNA expression to physiological phenomena, the results obtained for FP mRNA expression opens new doors for the study of hormonal protocols associated with cloprostenol sodium in the puerperium of Zebu females.

Efficacy of a treatment with hCG 4 days after AI to reduce pregnancy losses in lactating dairy cows after synchronized ovulation

Content The objective of the study was to investigate whether a treatment with hCG 4 days after AI could reduce pregnancy losses in lactating dairy cows. Cows of a dairy herd presented to the veterinarian in a fixed reproductive management protocol were treated with an Ovsynch protocol if no corpus luteum (CL) could be palpated per rectum (Group OV). Cows with a CL received cloprostenol (0.15 mg). After 2 days, these cows were treated with buserelin (0.01 mg) and received timed AI 16-20 h later (Group PG). In both treatment protocols, cows were assigned to two groups to receive 2500 IU of hCG i.v. 4 days after AI or to serve as untreated controls (Groups OV-hCG, OV-Control, PG-hCG and PG-Control). Pregnancy diagnosis was carried out 27 days after AI via ultrasonography and 39 days after AI by rectal palpation. Pregnancy losses were defined as cows being pregnant on day 27 but not pregnant on day 39 after AI. Pregnancy rate (PR) by day 27 did not differ among the four groups (35.4, 35.0, 37.0 and 38.0% for Groups OV-hCG, OV-Control, PG-hCG and PG-Control, respectively). Pregnancy losses between day 27 and day 39 after AI were smaller in hCG treated animals in summer but not in autumn and spring. Pregnancy rate by day 39 after AI was higher in PG than in OV groups, but independent of hCG-treatment. In conclusion, treatment with hCG 4 days after AI did not significantly increase PR on 39 days after AI. A positive effect of hCG on pregnancy losses during the summer months warrants further investigation.

HPLC method for enantioselective analysis of cloprostenol

A new HPLC method for the separation and quantification of cloprostenol enantiomers was developed. The optimized separation system consisted of Chiralcel OD-RH column and acetonitrile-sodium dihydrogenphosphate (pH 3.0; 20mM) (33:67, v/v) as the mobile phase. Baseline resolution of (+/-)-cloprostenol (R=2.16) was achieved and the analysis time did not exceed 10 min. Limits of detection and quantification were units of micromol/l at 274 nm. The respective values decreased an order of magnitude at 210 nm. The R.S.D. values obtained for the retention factor, peak area and peak height of each enantiomer were less than 2%. Conditions for semipreparative separation of the enantiomers can be achieved easily just by a small adaptation of the mobile phase composition.

The effects of ovarian function on estrus synchronization with PGF in dairy cows

Milk progesterone concentration (P4), milk yield, milk composition, ovarian structures and pregnancy status were studied in 108 cows treated with two doses of PGF 14 days apart and inseminated at fixed time (TAI) 80-82 h later. The synchronization protocol was started at 70+/-1.4 days after parturition. Milk P4 profiles revealed that anestrus, failure of luteolysis following treatment with PGF and failure to ovulate following luteolysis were the main reasons for low pregnancy rate with TAI. Anestrous cows had a higher percentage of milk fat (P<0.05) and higher fat to protein ratio (P<0.01), and cows that did not undergo luteolysis had higher milk yield (P<0.05) and lower percentage of milk protein (P<0.05) than cows that responded to PGF treatment. Cows that did not undergo luteolysis and cows that did not ovulate following luteolysis had lower milk P4 during the luteal phase preceding the second PGF injection (P<0.01 and P<0.05, respectively). Pregnancy rates 24 and 47 days after TAI in cows that responded as expected to the synchronization treatment were 62% and 54%, respectively. Pregnancy was precluded in non-responsive cows. The largest follicle at the time of TAI in cows experiencing late embryonic mortality was smaller (P=0.02) than in cows that successfully maintained pregnancy. Results suggest that a primary reason for low pregnancy rate in dairy cows after administration of PGF and TAI is inappropriate ovarian function prior to, or following treatment.

Effect of repeated administration of PGF2alpha in the early post partum period on the prevalence of clinical endometritis and probability of pregnancy at first insemination in lactating dairy cows

Two experiments were performed to determine the effects of repeated administration of PGF2alpha in the immediate post partum period on the prevalence of clinical endometritis at 22 and 58 days post partum, and the probability of pregnancy at first insemination, in post partum dairy cows. In Experiment 1, 228 cows on day 7 post partum were used. Cows in Group 1 (n = 114) were treated twice with PGF2alpha (25 mg, im) 8 h apart on days 7 and 14 post partum, and only once on days 22 and 35 post partum. Cows in Group 2 (n = 114) served as untreated controls. Vaginoscopy and transrectal palpation of the genital tract were done on days 22 and 58 post partum. Cows in both groups were inseminated at estrus after a voluntary waiting period of 100 days. Pregnancy was determined by transrectal palpation between 45 and 50 days after insemination. Repeated administration of PGF2alpha in the immediate post partum period did not reduce the prevalence of clinical endometritis on days 22 or 58 post partum (65 versus 62% on day 22 and 28.3 versus 35.2% on day 58 in Groups 1 and 2, respectively). There was no significant difference in the probability of pregnancy at first insemination between cows in both groups. In Experiment 2, 418 cows on day 7 post partum were used. Cows in Group 1 (n = 209) were treated twice with PGF2alpha (25 mg, im) 8h apart on days 7 and 14 post partum, and only once on days 22 and 35 post partum. Cows in Group 2 (n = 209) served as untreated controls. Cows in both groups were subjected to the Presynch and Ovsynch protocols on days 49 and 75 post partum, respectively. Pregnancy was determined by transrectal ultrasonography between days 29 and 32 after timed insemination. There was no significant difference in the probability of pregnancy at first insemination between cows in both groups. In conclusion, repeated administration of PGF2alpha to cows in this herd had no effect on the prevalence of clinical endometritis at 22 and 58 days post partum, and that there was no effect on the probability of pregnancy after insemination at estrus among cows with a voluntary waiting period of > 100 days, or at timed AI at 85 days in milk when Presynch was employed.

Analysis of cow factors influencing conception rates after two timed breeding protocols

The objective of this study was to determine cow factors that influence conception rates after timed artificial insemination (TAI) on a commercial dairy farm. In Trial 1, 197 cows were synchronized by an administration of 25 mg of dinoprost between Days 48 and 54 post partum and again 14 days later. Cows were inseminated 66 and 90 hours after the second treatment. In Trial 2, 186 cows were treated with an Ovsynch protocol consisting of an administration of 0.02 mg of buserelin between Days 62 and 68 post partum, a treatment with 0.75 mg of tiaprost 7 days later and a second treatment with buserelin 48 h later. Cows were bred 16 to 20 hours after the last treatment. Cows with abnormal vaginal discharge at the time of insemination were excluded from AI. Lactation number, milk yield, fat and protein content of milk, signs of endometritis at an examination 14 to 20 days post partum and month of breeding were included as potential factors influencing conception on TAI. Conception rates after timed breeding were 32.0% and 30.6% in Trials 1 and 2, respectively. Logistic regression revealed that neither milk production parameters nor endometritis at post partum examination influenced conception rates in either of the two timed breeding protocols. Only parity showed an effect (P=0.012) in Trial 2. Primiparous cows were more likely to conceive after timed breeding than older cows (43.5 vs. 23.1%). An effect of parity, however, was not observed in Trial 1. It can be concluded that neither milk production nor endometritis at an examination 14 to 20 days post partum influence conception rates after TAI if cows with abnormal vulval discharge at the designated time of AI are excluded from breeding.

Effect of one spontaneous estrus cycle (after synchronization with PGF2alpha) on reproductive performance in dairy cows

The objective of the study was to analyze the effect of a spontaneous estrus cycle after synchronization of estrus with prostaglandin F2alpha (PGF2alpha) in dairy cows on the degree of synchronization and reproductive performance. We assigned 557 Holstein cows to two treatment groups. In Group 1 estrus was synchronized by two treatments with 25 mg of Dinoprost-Trometamol in 14-day intervals. Cows were treated 27 to 33 days postpartum (dpp) and 41 to 47 dpp, respectively. Cows in Group 2 were treated with 25 mg of Dinoprost-Trometamol three times in 14-day intervals, starting at 34 to 40 dpp. The second and third injections were administered at 48 to 54 dpp and 62 to 68 dpp, respectively. All cows were inseminated on observed estrus after a voluntary waiting period of 65 days post partum. Thus cows in Group 1 were inseminated on spontaneous estrus and cows in Group 2 on induced estrus. Cows not inseminated at 80 days post partum were palpated per rectum and treated according to a predefined protocol. Herd reproductive performance measures did not differ significantly between groups. The proportion of cows with low serum progesterone levels was significantly higher 3 days after synchronization than 24 days after synchronization (97% vs 39%). The first-service conception rate was 34.8% in Group 1 and 30.7% in Group 2 (P > 0.05). Days open were 113.5 in Group 1 and 110.9 in Group 2 (P > 0.05). It is concluded that postponing artificial insemination for one spontaneous estrus cycle after synchronization decreased the degree of synchronization. This procedure, however, had no effect on herd reproductive performance compared to insemination on first observed estrus after synchronization.

Synchronization of lactating dairy cows with prostaglandin F2 alpha: insemination on observed oestrus versus timed artificial insemination

The effect of two insemination policies after synchronization of oestrus on reproductive performance in two groups of cows was investigated. Oestrus was synchronized by two treatments with prostaglandin F2 alpha (PGF2 alpha) at a 14-day interval. Cows in Group 1 (n = 234) were inseminated twice on appointment 66 and 90 h after the second treatment. Cows in Group 2 (n = 222) were intensively watched for signs of oestrus after the synchronization protocol and inseminated on observed oestrus. Cows with abnormal discharge after synchronization were excluded from breeding and inseminated later during the study period. Service rate within 1 week after synchronization was higher in Group 1 than in Group 2 (89.3 versus 67.1%). Conception rates on first service did not differ between groups (33.2 versus 30.0%). Days to first service and days open were shorter in Group 1 (P < 0.05). The number of cows culled for infertility did not differ between the groups. Endometritis 14-20 days post-partum decreased the percentage of cows pregnant at the end of the study period in both groups but did not have a significant effect on conception rates and days open. It is concluded that additional inseminations required in the timed artificial insemination protocol were economically justified by the reduction in days open in comparison with insemination on observed oestrus after synchronization.