PSV-3 Ovarian dynamics of brahman cows submitted to five-day or twelve-day progesterone-based estrus synchronization protocol

The aim of this study was to investigate the ovarian response of Brahman cows submitted to two different estrus synchronization protocols and to determine the estrus response and ovulation time. A total of 153 Brahman cows were randomly assigned to receive one of the following estrus synchronization protocols: 1) CIDR insert and an injection of prostaglandin F2α (25 mg, PGF) on Day -5 and CIDR removal with PGF on Day 0 (CIDR5; n = 77); 2) CIDR insert on Day -12 and an injection of PGF on Day -12, Day -5 and Day 0 upon CIDR removal (CIDR12; n = 76). Estrotect breeding indicator patches were placed on Day 0 and cows were artificially inseminated (AI) 12h after estrus detection; cows not detected in estrus after 96h received TAI coupled with 100 µg of GnRH. Ovarian dynamics were observed during the protocol and follicular diameter were measured every 12h after AI until ovulation. Cows synchronized with CIDR12 had increased follicular diameter (CIDR5, 10.19 ± 0.51 vs. CIDR12, 13.12 ± 0.52 mm; P = 0.01) and decreased serum concentrations of progesterone (CIDR5, 1.68 ± 0.12 vs. CIDR12, 0.81 ± 0.12 ng/ml; P < 0.01) at CIDR removal. The percentage of cows exhibiting estrus did not differ between treatments (CIDR5, 66.2 vs. CIDR12, 64.5%; P = 0.25). No difference was observed in ovulation rate (CIDR5, 94.1 vs. CIDR12, 94.1%; P = 0.6). Time of estrus expression and ovulation time after CIDR removal did not differ (CIDR5, 59.9 ± 2.3 vs. CIDR12, 61.5 ± 2.3h; P = 0.71 and CIDR5, 88.1 ± 2.6 vs. CIDR12, 90.9 ± 2.6h; P = 0.75; respectively). In conclusion, extended length of CIDR with additional PGF increased follicular diameter and decreased concentrations of progesterone but did not influence estrus response and ovulation time in Brahman cows.

PSXII-20 Ovarian dynamics and fertility in beef cows administered a 5-day or 6-day CO-Synch protocol for timed artificial insemination

The 5-day CO-Synch is an extensively used TAI protocol; however, it requires multiple administrations of prostaglandin F2α (PGF). The objective of the present study was to evaluate the effect of increasing progesterone (P4) device insertion from 5 to 6 days during a TAI protocol on ovarian dynamics and fertility in beef cows. Suckled beef cows (n = 867) at six locations were randomly assigned to either a 5-day or 6-day CO-Synch. Cows received an intravaginal P4 device (CIDR, Zoetis) and 100 µg of gonadorelin acetate (GnRH, Parnell) on d-9 (6-day) or d-8 (5-day). On d-3 CIDR’s were removed, an estrus detection patch applied (Estrotect, Rockway Inc.) and either one (6-day) or two (5-day) doses of PGF (500 µg of cloprostenol sodium, Estroplan, Parnell) was administered. On d0 (72 h after CIDR removal) all cows received 100 µg of GnRH, estrus expression was evaluated, and AI was performed. Pregnancy was determined by ultrasonography 34 days after TAI. Ovarian dynamics were evaluated in a subset of animals (n = 20) between d-3 and d7 to determine preovulatory follicle size, time of ovulation and corpus luteum (CL) size. Data were analyzed using generalized linear mixed models (SAS 9.4). Cows in the 6-day group tended (P = 0.09) to have a larger maximum follicle diameter (16.2±0.4mm) than cows in the 5-day group (15.0±0.6mm). In addition, CL volume on d7 was greater (P = 0.01) in the 6-day (4302±495mm3) than 5-day (2406±455mm3) group. There were, however, no differences (P = 0.15) in the interval between CIDR removal and ovulation. Cows assigned to the 6-day group had greater (P < 0.05) estrus expression [56.1% (215/385) vs 41.5% (161/388)] and pregnancy rate [54.6% (236/438) vs 47.4% (207/435)] than cows in the 5-day group. In conclusion, extension of the period of P4 device insertion in a prolonged proestrus protocol increases preovulatory follicle size, estrous expression, and fertility to TAI.

Ovarian dynamics, hormone profiles, and characterization of ovarian and uterine blood flow in cycling Sahiwal cows

The objectives were to investigate the ovarian dynamics and hormonal profiles during the oestrus cycle, and to characterize the ovarian and uterine blood flow (OBF versus UBF) indices on the extent of vascular perfusion towards the dominant follicle (DF) or corpus luteum (CL) during the peri-ovulatory follicular wave in Sahiwal cows. In experiment 1, cyclic cows (n = 21) were selected at their spontaneous oestrus (day 0) and subjected to B-mode ultrasonography throughout the oestrus cycle. In experiment 2, cyclic cows (n = 9) were randomly selected at day 0, and categorized according to the intra-ovarian patterns as ovaries with DF (n = 3), CL (n = 3) or both (DF+CL; n = 3) to characterize the OBF and UBF indices using Doppler ultrasonography. The length of the oestrus cycle (days), number of follicular waves (n) and size (mm) of DF and CL were 20.1 ± 0.9, 2.1 ± 0.2, 14.7 ± 0.7 and 15.9 ± 2.5, respectively. The concentrations (ng/mL) of plasma progesterone increased linearly, and a peak was attained at day 12.2 ± 1.0. However, it reduced linearly with the onset of luteolysis at day 16.4 ± 0.3 of the oestrus cycle. The plasma progesterone (P4) concentrations and the diameter of CL correlated throughout the oestrus cycle. The mean OBF and UBF indices did not differ between intraovarian patterns. Taken together, this information on reproductive physiological parameters could be used to develop synchronization protocols to improve reproductive management in Sahiwal cows.

EFFECT OF THE ADMINISTRATION OF SERUM AND RECOMBINANT EQUINE CHORIONIC GONADOTROPIN ON OVARIAN DYNAMICS AND CONCEPTION RATE IN ANESTRUS PRIMIPAROUS BRANGUS COWS

The objective was to determine the size of the dominant ovulatory follicle, the ovulation time and the conception rate of cows in anestrus treated with serum equine chorionic gonadotropin (eCG), recombinant chorionic gonadotropin and untreated controls. 57 anestrus primiparous Brangus cows were used with 70 ± 26 days of calving and a body condition of 2.50 ± 0.15. They were synchronized with a FTAI protocol based on estrogen and progesterone devices (DI). Upon removal of DI, 3 groups were made according to the type of eCG applied: serum eCG received 400 IU im of equine Chorionic Gonadotropin, recombinant eCG received 140 IU of recombinant Equine Chorionic Gonadotrophin and Control did without treatment. Follicular size and time of ovulation (normal or abnormal) was determined at DI removal, during FTAI and 7 days later. An ANOVA was performed to determine the effect of the treatment on ovarian dynamics and a chi-square test and correspondence analysis to establish associations. In normal ovulation cows at the FTAI, 94.4% of the serum eCG, 55.5% of the recombinant eCG and 71.4% of the Control cows presented a dominant ovulatory follicle (DOF), which in those treated with serum eCG, it was 1.4 mm greater in relation to the Control (P = 0.0073). The ovulation rate, in normal and abnormal ovulation cows, was 94.4% for serum eCG, and for recombinant eCG and 66.6% for Controls. A significant association was detected between ovulation time and the treated groups (P = 0.0042). Normal ovulation was 38.9% higher in cows with serum eCG in relation to those treated with recombinant eCG and 50.8% in comparison with Control. A significant relationship was observed between the conception rate and the groups treated with the different Gonadotropins (P = 0.0574), being 66.7% in serum eCG, 50% in recombinant eCG and 28.6% in the Control. The use of eCG, either serum or recombinant, in anestrus primiparous cows, stimulates the development of DOF at FTAI, increases ovulation rate and improves conception in relation to untreated cows.

Evaluation of Double Ovsynch Protocol in Acyclic Jaffarabadi Heifers and Buffaloes with Respect to Ovarian Dynamics, Hormonal Profile and Fertility

Background: Anestrus is one of the most commonly encountered infertility problems in cattle and buffalo in India. Jaffarabadi is one of the heaviest buffalo breeds of the world and is a native of Saurashtra region of Gujarat. The breed is known for poor reproductive efficiency. To improve its reproductive efficiency, this study was undertaken on acyclic Jaffarabadi animals employing double Ovsynch protocol and its assessment through ovarian dynamics and blood biochemical and endocrine profile on a farm. Methods: The study included acyclic post-pubertal Jaffarabadi heifers (age 42±2 and 48±2 months; Gr-I and Gr-II, n=6 each) and the postpartum lactating acyclic buffaloes (Gr-III, n=6) using a double Ovsynch protocol, which consisted of i/m injections of 20 µg Buserelin acetate on days 0, 10, 17 and 26 and 500 µg Cloprostenol sodium on days 7 and 24, with a timed insemination on day 27. Ovarian dynamics was monitored by performing ultrasonography using real-time B-mode ultrasound scanner together with blood sampling for hormonal and biochemical profile on each day of hormone therapy and then on days 0, 12, 21 and 35 post-AI. The animals inseminated at induced estrus/FTAI were followed for return to estrus, if any. Pregnancy was confirmed in non-return cases on day 35 by ultrasonography and on day 70 by per rectal examination. The findings on ovarian dynamics, plasma endocrine and biochemical profile were compared statistically between groups and periods and fertility rates between groups. Result: In animals of treatment group I and II, a significant (p less than 0.05) increase in numbers of small follicles was observed on day 26. Number of large sized follicles was significantly (p less than 0.05) higher on day 26 in comparison to day 0 and day 7 in group III animals. Large and subordinate follicular diameters increased gradually, but the differences between periods were significant (p less than 0.001) only in group III with the highest diameter of large follicle on day 17. Plasma FSH and LH concentrations differed significantly (p less than 0.001) among groups at all-time intervals. Plasma LH in group I and III differed significantly (p less than 0.001). Plasma estrogen level was significantly (p less than 0.05) higher in group II than group III. Plasma progesterone concentrations in group I and II animals were significantly higher on day 35 post-AI. Plasma insulin levels were significantly (p less than 0.01) lower on all days for group III animals than group I and II. Blood glucose level was significantly (p less than 0.001) higher in group I on day 17 as compared to group II and III. Plasma total cholesterol was significantly (p less than 0.05) higher in group III as compared to group I and II. The conception rates at first service/FTAI in double Ovsynch treated animals of group I, II and III were 66.66, 83.33 and 16.66 %, respectively. Thus it was concluded that ovarian structures and the plasma endocrine profile reflected the ovarian response to different hormonal injections and that double Ovsynch protocol could be a better choice for improving conception rate in post-pubertal acyclic Jaffarabadi buffalo heifers as compared to multiparous acyclic buffaloes.