Estrus Synchronization Protocol Research Articles

90 Effect of the gonadotrophin-releasing hormone antagonist on the sheep follicular population

The present study was designed to study the follicular population dynamics followed or not by treatment with different doses of the GnRH antagonist in sheep. A total of 18 ewes were submitted to short-term oestrus synchronization protocol (Oliveira et al. 2009 Proc. Braz. Congr. Anim. Reprod.). The animals were 2 or 3 years old, multiparous, and had a body score of 3 to 3.5. On Day 7 after ovulation of synchronized oestrus, females were randomly divided into groups (n=6/group) according to the dose of the gonadotrophin-releasing hormone (GnRH) antagonist (Firmagon®, Ferring Pharmaceuticals) subcutaneously administered: G-control: placebo treatment (administration of saline solution); G-lower dose: 215 µg/kg; and G-higher dose: 235 µg/kg of bodyweight. B-mode ultrasound exams of the ovaries were conducted daily from 1 day before treatment with GnRH antagonist until the females showed oestrous behaviour. Ultrasound equipment (MyLab Vet®, Esaote) was used coupled to a transrectal linear transducer with a frequency of 6 and 8MHz to assess the ovarian population. Data were compared between groups, evaluation days, and their interaction by ANOVA with post hoc using Tukey’s test (P<0.05). There was no interaction (P>0.05) between the studied effects (treatments and evaluation days). The number of small follicles (2–3.49mm) was higher (P=0.0002) in the G-lower dose (5.4±0.4) compared with the G-control (4.1±0.3) and G-higher dose (3.5±0.2). The number of large follicles (≥4.5mm) was lower (P=0.01) in the G-higher dose (0.2±0.0) compared with the G-control (0.5±0.1) and G-lower dose (0.4±0.1). The number of medium follicles (3.5– 4.49mm) and the average diameter of the follicles in the 3 categories of diameter did not differ (P>0.05) between groups. The number of medium follicles differed (P=0.0131) between Days 8 and 15 after synchronized oestrus ovulation. The number of large follicles on Day 6 differed (P=0.0002) of Days 8, 9, 10, 11, 12, 16, and 17. The average diameter of medium follicles differed (P=0.0095) between Days 8 and 10. The number of small follicles and the average diameter of small and large follicles did not differ (P>0.05) between days. In conclusion, the administration of the GnRH antagonist at a higher dose in sheep suppressed the development of large tertiary or antral follicles, whereas at a lower dose, it led to an increase in the population of small follicles.

Evaluation of the relationship between serum paraoxonase-1 activity and superovulation response/embryo yield in Holstein cows.

In this study, the effect of serum paraoxonase-1 (PON-1) activity on superovulation response and embryo yield was evaluated. The study material comprised 50 Holstein cows aged 3–4 years on postpartum day 90–120 with a body condition score of 3–3.25. A progesterone-based estrus synchronization protocol was initially administered to the selected donors. For this purpose, progesterone source was inserted intravaginally (day 0) and gonadotropin-releasing hormone injection was performed (day 6). Seven days after the insertion of progesterone device, follicle-stimulating hormone injections (total dose of 500 µg in decreasing doses for 4 days) were administered for superovulation. On the morning of the ninth day, prostaglandin (PG) F2α was administered, and the progesterone device was removed from the vagina in the evening on the same day. Two days after PGF2α administration, fixed-time artificial insemination was performed in the morning and in the evening. On the day of artificial insemination, blood samples were taken from the donors to determine the serum PON-1 activity. Uterine flushing was performed seven days after insemination. The results revealed that the serum PON-1 activity (mean ± SD, 562.71 ± 140.23 U/l) of the cows that responded to superovulation (donors with total corpus luteum count of ≥3 in both ovaries) was higher than those (389.91 ± 80.51 U/l) that did not (P<0.05). On the day of insemination, a positive correlation was determined between serum PON-1 activity and the counts of total corpus luteum (r=0.398), total oocyte/embryo (r=0.468), transferable embryo (r=0.453), and Code I embryos (r=0.315, P<0.05). Unlike the Code I embryos, there was no significant correlation between serum PON-1 activity and the number of Code III embryos. Moreover, no significant difference in the number of Code III embryos between the two PON-1 groups was observed. However, embryo yield and quality were found to have increased with increased PON-1 activity. Therefore, it was concluded that serum PON-1 activity may be associated with superovulation response, embryo yield and quality in donor cows.

Intravaginal administration of estradiol benzoate capsule for estrus synchronization in goats.

Estrus synchronization requires multiple treatments of hormonal drugs, requiring considerable time and cost. The aim of the present study was to develop an estrus synchronization protocol using intravaginal administration of estradiol benzoate (EB) capsules in goats. Two types of capsules were prepared: an EB capsule that melted immediately after administration and a sustained-release (SR) EB capsule that dissolved slowly and reached a peak after 24 h. Goats with functional corpus lutea were intramuscularly treated with prostaglandin F2α (PG). At 24 h after PG administration, goats were administered 1 mg of EB solution intramuscularly (PG + 24IM; n = 6) or 1 mg of EB capsule intravaginally (PG + 24EB; n = 6). The SR EB capsule was administered intravaginally at the time of PG administration (PG + SR; n = 6). The control group (n = 6) received only PG. All groups showed estrus within 72 h after PG administration. The onset of estrus did not differ significantly between the PG + 24IM and PG + SR groups but was earlier than in the control group. Estradiol concentration in the PG + SR group peaked at 11.5 ± 6.1 h after EB and PG administration. Peak estradiol concentrations were not significantly different between the PG + 24IM and PG + SR groups (78.0 ± 25.8 and 64.0 ± 38.1 pg/ml, respectively), and were higher than the PG + 24EB and control groups (27.3 ± 8.8 and 14.6 ± 6.1 pg/ml, respectively). These results suggest that intravaginal administration of an EB capsule with a sustained-drug release base is applicable for estrus synchronization, as an alternative to intramuscular administration.

114 Short-term hormonal protocol efficiency either with or without equine chorionic gonadotrophin to promote oestrous synchronization in cyclic dairy goats

The use of equine chorionic gonadotrophin (eCG) in oestrous induction protocols is associated with antibody production against eCG. Moreover, there are important equine welfare issues involved in its production and the development of viable protocols without eCG in dairy goats is essential. The aim of this study was to assess oestrus and ovulatory responses of short-term oestrous synchronization protocol with or without eCG in nulliparous (NUL) and multiparous (MUL) dairy goats during the breeding season. On a random day of oestrous cycle (Day 0), Alpine (n=10 NUL and 10 MUL), Nubian (n=10 NUL and 10 MUL), and Saanen (n=10 NUL and 6 MUL) goats received 30μg of d-cloprostenol intramuscularly (IM) and an intravaginal sponge containing 60mg of medroxyprogesterone acetate, which was maintained for 6 days (Day 6). At 24h before sponge removal (Day 5), goats received IM 200IU of Novormon 5000 (G-eCG) or saline solution (G-Control). NUL and MUL goats of each breed were assigned equally into one of the two treatments. Transrectal ultrasonography was used to assess ovarian parameters, and teaser goats detected oestrus every 12h from sponge removal to ovulation or until 96h after sponge removal. The results are described as mean±s.e.m., and categorical results are presented as percentages. The normal distribution of the residues of all variables was determined by the Shapiro-Wilk test and for homoscedastic by Levene test. To evaluate interaction between treatments and parity order, the general linear model (GLM) was applied. Parametric variables were subjected to Student’s t-test. Nonparametric variables were analysed by Mann–Whitney test, Chi-squared test, and Fisher’s exact test. Values of P&amp;lt;0.05 were considered significant. According to the breed and parity order, Nubian and Saanen goats showed no difference (P&amp;gt;0.05) in reproductive parameters. Alpine goats had a longer (P&amp;lt;0.05) interval from sponge removal to onset of oestrus (SROE) in MUL (61±14.0h) than NUL (38.5±12.7h), longer interval from onset of oestrus to ovulation (IEOV) in NUL (33.5±11.9h) than MUL (19.5±13.4h), and the number of ovulations was greater (P&amp;lt;0.05) in MUL (2.2±0.9) than in NUL (1.3±0.5). In goats either receiving eCG or not, Alpine and Nubian goats had no difference (P&amp;gt;0.05) in SROE, IEOV, interval from sponge removal to ovulation (SROV), percentage of animals that ovulated, diameter of the ovulatory follicle, and number of ovulations. Saanen goats had a higher (P&amp;lt;0.05) percentage of animals that ovulated in G-eCG (87.5%) than G-control (25.0%). Regardless of parity order and breed, SROV was longer (P&amp;lt;0.05) in G-control (73.2±9.8h) than in G-eCG (65.1±10.2h), and the percentage of animals that ovulated was greater (P&amp;lt;0.05) in G-eCG (96.4%) than in G-control (67.9%). In summary, in short-term protocols for oestrous synchronization in cyclic dairy goats, the addition of eCG led to a shorter interval from sponge removal to ovulation and increased number of animals that ovulated. This research was supported by CNPq (310166/2012-8) and Embrapa (20.19.01.004.00.03.001).

22 Comparison of vaginal microbiome and concentrations of estradiol at artificial insemination in Brangus heifers

Abstract The knowledge surrounding the bovine vaginal microbiome and its implications on fertility and reproductive traits remains incomplete. The objective of the current study was to characterize the bovine vaginal microbiome and estradiol concentrations at time of artificial insemination (AI). Brangus heifers (n = 78) underwent a 7-d Co-Synch + CIDR estrus synchronization protocol. At AI, a double guarded uterine culture swab was used to sample the anterior vaginal tract. Blood samples were collected by coccygeal venipuncture to determine concentrations of estradiol. Heifers were retrospectively classified as pregnant (n = 29) versus nonpregnant (n = 49) on day 35. Lastly, heifers were classified into low (1.1 - 2.5 pg/ml; n = 21), medium (2.6 - 6.7 pg/ml; n = 30), and high (7.2 - 17.6 pg/ml; n = 27) concentrations of estradiol. The vaginal bacterial community composition was determined through sequencing of the V4-V5 region from the 16S rRNA gene using the Illumina Miseq platform. ANOVA was used to compare the diversity metrics between treatment groups. PERMANOVA was utilized to determine variation in community structure. There were no statistical differences in the Shannon diversity index (alpha diversity; P = 0.336) or principal component analysis (beta diversity; P = 0.744) of pregnant versus nonpregnant animals. The vaginal microbiome of pregnant and nonpregnant animals was similar with the four most abundant phyla being Tenericutes, Proteobacteria, Fusobacteria, and Firmicutes. Overall bacterial community composition in animals with high, medium, or low concentrations of estradiol did not differ (P = 0.512). These results indicate that concentration of estradiol does not impact vaginal microbiome composition. In conclusion, the composition of the bovine vaginal microbiome, although dynamic, may not be directly linked to an animal’s reproductive ability.

182 Uterine gene expression of beef cows in response to supplementation with calcium salts of soybean oil

Abstract We hypothesize that expression of peroxisome proliferator-activated receptors (PPARs; PPARa, PPARg, PPARd) and prostaglandin synthases (PGES, AK1B1) in endometrial tissue of Bos taurus beef cows changes after supplementation with calcium salts of soybean oil (CSSO) rich in omega-6 fatty acids compared to a saturated fat. Multiparous cows, stratified by BW (658.05±16.64 kg) and BCS (7.52±0.18), were randomly assigned to one of two treatments: 1) 0.7 kg/(hd.d-1) corn gluten feed + 0.1 kg/(hd.d-1) of prilled saturated fatty acids (Energy Booster, Milk Specialties, Eden Prairie, MN; CON, n = 12); or 2) 0.7 kg/(hd.d-1) corn gluten feed + 0.1 kg/(hd.d-1) of CSSO (Essentiom, Church and Dwight Co., Inc., Princeton, NJ; CSSO, n = 13). Cows were given a 21-d adaptation period before initiation of the experiment, maintained on common pasture, provided ad libitum access to forage and water, and individually fed treatments. Cows underwent a 7-d CO-Sync+CIDR estrus synchronization protocol beginning d0. Transrectal ultrasonography was performed d14 to determine location of a corpus luteum (CL). Uterine biopsies were collected d18 and d28 of the study, corresponding to d8 and d18 of the estrous cycle, respectively. One biopsy was taken from the anterior-most portion of uterine horns ipsilateral and contralateral to the CL for RNA extraction. Transcript expression was analyzed with reverse transcriptase qPCR and quantified using the 2-ddCt method with GAPDH as reference gene. There was no treatment effect for any transcripts analyzed (P ≥ 0.30), nor an interaction between treatment, horn relative to CL, and day (P ≥ 0.11). Transcript expression increased for both treatments from d18 to d28 for PPARa (0.8±0.18 vs. 1.8±0.22, P = 0.01), PPARd (1.13±0.12 vs. 1.9±0.13, P &amp;lt; 0.01), PPARg (1±0.2 vs. 1.3±0.25, P = 0.01), and AK1B1 (0.62±0.16 vs. 2.34±0.22, P &amp;lt; 0.01). While uterine transcript expression of selected genes increased through the luteal phase, supplementing beef cows with CSSO did not affect transcript expression compared to cows receiving saturated fat.

23 Comparison of vaginal microbiome and concentrations of estradiol at artificial insemination in Brangus heifers

Abstract The knowledge surrounding the bovine vaginal microbiome and its implications on fertility and reproductive traits remains incomplete. The objective of the current study was to characterize the bovine vaginal microbiome and estradiol concentrations at time of artificial insemination (AI). Brangus heifers (n = 78) underwent a 7-day Co-Synch + CIDR estrus synchronization protocol. At AI, a double guarded uterine culture swab was used to sample the anterior vaginal tract. Blood samples were collected by coccygeal venipuncture to determine concentrations of estradiol. Heifers were retrospectively classified as pregnant (n = 29) versus nonpregnant (n = 49) on day 35. Lastly, heifers were classified into low (1.1 - 2.5 pg/ml; n = 21), medium (2.6 - 6.7 pg/ml; n = 30), and high (7.2 - 17.6 pg/ml; n = 27) concentrations of estradiol. The vaginal bacterial community composition was determined through sequencing of the V4-V5 region from the 16S rRNA gene using the Illumina Miseq platform. ANOVA was used to compare the diversity metrics between treatment groups. PERMANOVA was utilized to determine variation in community structure. There were no statistical differences in the Shannon diversity index (alpha diversity; P = 0.336) or principal component analysis (beta diversity; P = 0.744) of pregnant versus nonpregnant animals. The vaginal microbiome of pregnant and nonpregnant animals was similar with the four most abundant phyla being Tenericutes, Proteobacteria, Fusobacteria, and Firmicutes. Overall bacterial community composition in animals with high, medium, or low concentrations of estradiol did not differ (P = 0.512). These results indicate that concentration of estradiol does not impact vaginal microbiome composition. In conclusion, the composition of the bovine vaginal microbiome, although dynamic, may not be directly linked to an animal’s reproductive ability.

Relationship between total antioxidant/oxidant status, and oxidative stress index and superovulation response in donor cows

• TAS, TOS, and OSI affect superovulation response in donor cows. • Positive correlation was determined between TAS and transferable embryo count, and embryo quality. • TOS and OSI were negatively correlated with the count of transferable embryo. • Positive correlation was found between unfertilized oocyte count and TOS, and OSI. The aim of the present study was to determine the effects of serum total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) on counts of corpus luteum, transferable embryo, and embryo quality in cows treated with superovulation protocol. A total of 60 Simmental cows (postpartum 90 to 120 days) were used. The donors were treated with a 9 day-progesterone based estrus synchronization protocol. On the 7th day of the progesterone treatment, donors were treated with FSH twice daily as decreasing doses for 4 days. On day 9, PGF 2α injection was performed in the morning and progesterone source was removed in the evening. The cows were inseminated twice artificially on day 11 at 12 hours interval. On the day of artificial insemination, blood samples were collected to determine serum TAS, TOS and OSI concentrations. Uterine flushing was performed on day 7 after artificial insemination. Serum TAS, TOS and OSI concentrations of cows were 1.62 μmol/L, 5.44 μmol/L and 0.45 AU, respectively. There was a positive correlation between TAS concentration and the counts of transferable embryo, Code I and II quality embryo ( P <0.05). TOS and OSI concentrations were negatively correlated with the counts of transferable embryo and Code I embryo, and positively correlated with unfertilized oocyte counts ( P <0.05). As a result, it was concluded that TAS, TOS, and OSI affected the counts of transferable embryo, embryo quality, and unfertilized oocyte in donor cows.

Oestrus Synchronisation with Progesterone-containing Sponge and Equine Chorionic Gonadotropin in Pirlak Ewes During the Non-breeding Season: Can Toryum Improve Fertility Parameters?

IntroductionThe aim of the study was to determine the effect of the vitamins, omega-3 polyunsaturated fatty acid and minerals in the supplement Toryum administered before and during oestrus synchronisation on some fertility parameters of ewes during the non-breeding season.Material and MethodsThe experimental animals were clinically healthy Pirlak ewes, 55–75 days postpartum, aged 2–4 years and weighing 40–50 kg. A sponge was inserted into the vagina for 10 d (G1, n = 30; G2, n = 30) or 14 d (G3, n = 30; G4, n = 30) for oestrus synchronisation, and on the day of removal, 400 IU equine chorionic gonadotropin was injected. Toryum soft capsules were administered individually (1 capsule/ewe p.o.) to G1 and G3 ewes seven days before the sponge was inserted and on the day it was removed. Oestrus detection was started 12 h after sponge removal. Pregnancy was diagnosed by transrectal ultrasonography on the 30th day after mating.ResultsThe pregnancy rate was statistically different between G1 and G4 (P < 0.05). The onset of oestrus was statistically different (P < 0.001) between the 10-d groups (G1 and G2) and the 14-d groups (G3 and G4). The litter size and oestrus, conception, lambing, multiple birth, and survival rates were not significantly different between the groups (P > 0.05).ConclusionToryum administered to Pirlak ewes during progesterone-based oestrus synchronisation protocols during the non-breeding season may increase pregnancy rates. The relationship between Toryum and fertility parameters in ewes would be better understood by comprehensive studies.

Comparison of Calving and Conception Rate after Timed Artificial Insemination (AI) with Estrus Synchronization Protocols in Crossbred Cows under Field Conditions

Comparison of Calving and Conception Rate after Timed Artificial Insemination (AI) with Estrus Synchronization Protocols in Crossbred Cows under Field Conditions

Effect of Ovsynch Estrus Synchronization Protocol on Fertility in Crossbred Ewes

Effect of Ovsynch Estrus Synchronization Protocol on Fertility in Crossbred Ewes

Effect of different protocols for estrus synchronization on reproductive performance of Santa Inês ewes under Amazon environmental conditions

The objective of this study was to evaluate the effect of different hormonal protocols on the reproductive performance of Santa Inês ewes in Amazon environmental conditions. Twenty-two Santa Inês ewes between 3 and 4 years-old were distributed in a randomized block experimental design, where the treatments consisted of two protocols for estrus synchronization (short and long) with eleven animals each. Data on the occurrence of estrus were described for each protocol. Data of estrus, pregnancy, and prolificity were firstly subjected to ANOVA and a subsequent Tukey’s test. Results were considered significant at p ≤ 0.05. The short-term protocol presented an interesting successful rate, where above 70% ewes tested had estrus. The long-term protocol also achieved a high successful rate, where above 80% ewes tested had estrus. However, comparing the protocols, the long-term protocol presented better results of positive estrus and pregnancy rates in ewes. Thus, it can be concluded that both protocols presented satisfactory results regarding estrus manifestation, and prolificity (lambs produced per ewe). However, under Amazon environmental conditions, the long-term protocol presented better results regarding positive manifestation of estrus and pregnancy rate.

Supplementation frequency and amount modulate postweaning growth and reproductive performance of Bos indicus-influenced beef heifers.

This 2-yr study evaluated the growth and puberty attainment of Bos indicus-influenced beef heifers offered 2 different postweaning concentrate supplementation amounts and delivery frequencies. On day 0 of each year, 64 Brangus crossbred heifers were stratified by initial body weight (BW) and age (mean = 244 ± 22 kg; 314 ± 17 d) and assigned into 1 of 16 bahiagrass pastures (4 heifers/pasture/yr). Treatments were randomly assigned to pastures in a 2 × 2 factorial design (4 pastures/treatment/yr) and consisted of concentrate dry matter (DM) supplementation at 1.25% or 1.75% of BW which were offered either daily (7×) or 3 times weekly (3×) for 168 d. On day 56 of each year, heifers were assigned to an estrus synchronization protocol consisting of intravaginal controlled internal drug release (CIDR) insertion on day 56, CIDR removal on day 70, i.m. injection of 25 mg of prostaglandin F2α (PGF2α) on day 86, and i.m. injection of 100 µg of gonadotropin-releasing hormone and timed-AI at 66 h after PGF2α injection (day 89). Heifers were exposed to Angus bulls from day 89 to 168 (1 bull/pasture). Pregnancy diagnosis was assessed on day 213 of each year. Supplementation amount × frequency effects were not detected (P ≥ 0.12) for any variable, except for plasma concentrations of glucose (P = 0.10) and urea nitrogen (PUN; P = 0.01). Herbage mass, herbage allowance, and nutritive value did not differ (P ≥ 0.12) among treatments. Increasing supplementation DM amount from 1.25% to 1.75% of BW increased (P ≤ 0.05) plasma concentrations of insulin-like growth factor 1 (IGF-1), overall average daily gain (ADG), final BW, percentage of pubertal heifers on day 89, pregnancy and calving percentages, and percentage of heifers calving within the first 21 d of the calving season. However, reducing the supplementation frequency from daily to 3× weekly, regardless of supplementation amount, did not impact overall pregnancy and calving percentages (P ≥ 0.42), but caused (P ≤ 0.05) fluctuations in plasma concentrations of insulin and IGF-1 and decreased (P ≤ 0.03) overall ADG, final BW, puberty attainment on days 56, 89, and 168, and percentage of heifers calving during the first 21 d of the calving season. Hence, increasing the supplement DM amount did not prevent the negative effects of reducing the frequency of supplementation (3× vs. 7× weekly) on growth and reproduction of replacement Bos indicus-influenced beef heifers.

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The effect of clitoral stimulation post artificial insemination on pregnancy rates of multiparous Bos indicus beef cows submitted to estradiol/progesterone-based estrus synchronization protocol.

Clitoral stimulation after artificial insemination (AI) in beef cattle is a common practice utilized by AI technicians; however, the effect of clitoral stimulation during fixed-time AI (TAI) is still unknown. The objective of the present experiment was to evaluate the effect of clitoral stimulation on temperament responses and pregnancy rates to TAI in Bos indicus beef cows. A total of 1,186 multiparous Nellore cows across three different locations were assigned to an estradiol/progesterone-based estrus synchronization + TAI protocol (day -11 to 0). Cows were randomly assigned to receive either 3 s of clitoral stimulation (n = 602) or no clitoral stimulation (n = 584) immediately after TAI (day 0). Cow body condition score (BCS) was recorded on day -11. Estrus expression was evaluated based on estrus detection visual aid patch activation on day 0 (estrus, ≥50% activated; no estrus, <50% activated). Temperament was assessed by individual chute score based on a 5-point scale before TAI, and individual exit velocity was measured after clitoral stimulation. Pregnancy diagnosis was performed 30 d after TAI via transrectal ultrasonography. Pregnancy rate to TAI was positively affected by BCS (P < 0.01) and estrus expression (P = 0.03). Pregnancy rates of cows receiving clitoral stimulation did not differ (P = 0.39) from cows non-stimulated (47.5 ± 4.6% vs. 44.3 ± 4.6%, respectively). No interaction of clitoral stimulation and estrus expression was observed (P = 0.26). Chute score was positively correlated to exit velocity (P < 0.01; r = 0.29); however, clitoral stimulation did not affect exit velocity (P = 0.86). In summary, pregnancy rates to TAI are influenced by various factors and multiple strategies have the potential to increase the fertility of beef cows submitted to TAI; however, clitoral stimulation of Bos indicus beef cows did not improve TAI pregnancy rate.

Vaginal bacterial community composition and concentrations of estradiol at the time of artificial insemination in Brangus heifers.

The knowledge surrounding the bovine vaginal microbiota and its implications on fertility and reproductive traits remains incomplete. The objective of the current study was to characterize the bovine vaginal bacterial community and estradiol concentrations at the time of artificial insemination (AI). Brangus heifers (n = 78) underwent a 7-d Co-Synch + controlled internal drug release estrus synchronization protocol. At AI, a double-guarded uterine culture swab was used to sample the anterior vaginal tract. Immediately after swabbing the vaginal tract, blood samples were collected by coccygeal venipuncture to determine concentrations of estradiol. Heifers were retrospectively classified as pregnant (n = 29) vs. nonpregnant (n = 49) between 41 and 57 d post-AI. Additionally, heifers were classified into low (1.1 to 2.5 pg/mL; n = 21), medium (2.6 to 6.7 pg/mL; n = 30), and high (7.2 to 17.6 pg/mL; n = 27) concentration of estradiol. The vaginal bacterial community composition was determined through sequencing of the V4 region from the 16S rRNA gene using the Illumina Miseq platform. Alpha diversity was compared via ANOVA and beta diversity was compared via PERMANOVA. There were no differences in the Shannon diversity index (alpha diversity; P = 0.336) or Bray-Curtis dissimilarity (beta diversity; P = 0.744) of pregnant vs. nonpregnant heifers. Overall, bacterial community composition in heifers with high, medium, or low concentrations of estradiol did not differ (P = 0.512). While no overall compositional differences were observed, species-level differences were present within pregnancy status and estradiol concentration groups. The implications of these species-level differences are unknown, but these differences could alter the vaginal environment thereby influencing fertility and vaginal health. Therefore, species-level changes could provide better insight rather than overall microbial composition in relation to an animal's reproductive health.

Study of vaginal microbiota of Holstein cows submitted to an estrus synchronization protocol with the use of intravaginal progesterone device

The characterization of vaginal microbiota will help to understand some of the reproductive problems and mechanisms to improve cattle reproduction. The objective of this study was to characterize the vaginal microbiota of cyclical Holstein cows with different parturition orders using 16S rDNA sequencing. Animals were submitted to an estrus synchronization protocol with the use of intravaginal progesterone (P4) implants and were treated or not with ceftiofur hydrochloride. DNA samples were extracted from vaginal swabs on day 0 and 10 of the synchronization, and sequenced with the Illumina MiSeq platform with an average coverage rate of 10.000 reads per samples using a Single-End library for fragments of 300 bp. The main bacterial phyla found in the vaginal tract of Holstein cows, were Firmicutes (37.61%), Tenericutes (29.45%), Proteobacteria (17.47%) and Bacteriodetes (13.73%), followed by Actinobacteria (0.82%) and Spirochaetae (0.45%). The use of intravaginal P4 devices has increased the relative abundance of the genera Family XIII AD3011 and Family XIII unclassified (p < .049). We have also observed an effect of the number of calving on the vaginal microbiota composition, showing that multiparous cows have a greater bacterial diversity than primiparous animals (p < .05). The use of ceftiofur hydrochloride was effective to reduce the vaginal bacteria proliferation. This study describes for the first time the vaginal microbiota of cows synchronized with intravaginal progesterone devices, different from the traditional methods such as microbiological culture and biochemical tests. We have identified a large number of microorganisms commonly found in the gastrointestinal tract of cows, colonizing the vaginal microbiota.

Efficiency of Different Estrus Synchronization Protocols in Surti Goats

A total of 54-adult non-pregnant Surti goats were selected and randomly divided into three equal groups (n=18 each). Two groups were put under estrus synchronization protocols, viz., Double PGF2α protocol (Inj. Dinoprost 12.5 mg, i/m, 11 days apart with natural breeding from 72-144 hours of second PG inj.) and NC Synch protocol (PG 12.5 mg - GnRH 0.004 mg - PG 12.5 mg - GnRH 0.004 mg on days 0, 8, 15 and 18, respectively with natural breeding during 19-21 days) using standard management practices and 3rd group was kept as untreated control. All the goats were dewormed before initiation of treatment. The estrus response (100% each), duration of estrus, pregnancy rate at 60 days post-breeding (55.55 vs. 44.44 and 55.55 %), and kidding rate (100% each) were statistically same in control and synchronized goats. However, twins were in almost 50% of kidding under the NC Synch group compared to 25% in Double PG protocol and 40% in the control group, with almost 100% kid survival till weaning. Thus, NC Synch Protocol was better in terms of pregnancy rate (55 vs. 44%) and fecundity (1.5 vs. 1.0) over double PGF2α protocol, and even untreated control goats.

β-carotene Supplementation Increases Progesterone Concentration and Glutathione Peroxidase Activity Following Alternative Progesterone Primed Oestrous Synchronization Protocol in Goats

The present study evaluated the effect of β-carotene supplementation and oestrous synchronization protocol on ovarian activity and fertility of Saanen does during the breeding season. The supplemented group received 100 mg β-carotene during the breeding and all does were synchronised with Controlled Internal Drug Release dispenser (CIDR) and injected with cloprostenol at CIDR withdrawal. One group of does were injected with 300 IU of eCG, while in another group bucks wearing aprons were introduced at CIDR withdrawal. Does were artificially inseminated twice (48 and 60 h) with fresh undiluted semen. The onset and duration of oestrus, progesterone, oestrdiol-17β and glutathione peroxidase activity, oestrous response and conception rate were analysed. Synchronization protocol did not affect response to oestrus, onset and duration of oestrus and oestradiol-17β concentration. The male presence group had significantly higher conception rate (97%) than the eCG (72%) group. β-carotene supplemented group had higher progesterone concentration and glutathione peroxidase activity. Supplemental β-carotene during the breeding period therefore, could play an important role on establishment of pregnancy due to high progesterone concentration and glutathione peroxidase activity. Inclusion of male effect in progesterone based oestrous synchronization protocol improves conception rate. Therefore, male effect can be used as an alternative to equine chorionic gonadotropin in progesterone based oestrous synchronization protocols especially, where drugs for oestrous synchronization are not affordable.

Estrus Performance and Pregnancy Rate in Types of Local Cows on Different Estrus Synchronization Protocols

The research aimed to evaluate the onset of estrus, conception rate, pregnancy rate and duration of estrus in Bali cow, limousine cow and rambon cow after being administered with three different hormones to syncrhronize estrus. A randomized block design with two factors, type of cow and hormone dose, was performed. Fifty-four postpartum cows consisted of the three breeds were administered to a single dose of PGF2α (5 ml per cow), a double dose of PGF2α (10 ml per cow) and combination of PGF2α and hCG (1,500 IU per cow). An analysis of variance showed that different breeds did not associate with the hormone doses and their combination, as evident from the onset of estrus, duration of estrus, conception rates and service per conception. However, different cow breeds showed the same onset of estrus, service per conception and the different onset of estrus and pregnancy rates. On the other hand, different doses of PGF2α and its combination with hCG generated different onset of estrus, duration of estrus, and pregnancy rates, but shared common service per conception. In conclusion, Bali cow demonstrated a more appropriate fertility than Limousin cow and Rambon cow. A combination of PGF2α and hCG showed the most adequate hormonal treatment to synchronize the estrus compared to single and double doses of PGF2α.