Preovulatory follicular and subsequent luteal size influence pregnancy success in water buffaloes

5d CIDR-Heatsynch improves the circulatory estradiol levels, estrus expression and conception rate in anestrus buffalo (Bubalus bubalis)

The present study aimed to investigate whether increasing estradiol (E2) during preovulatory period would increase estrous expression, luteal profiles and conception rate in 5d CIDR based timed AI protocol. A total 156 anestrus buffalo allocated (78 per group) to either 5d CIDR-Cosynch (d-5: CIDR + GnRH; d0: PGF2α+CIDR removal; 72 h post-CIDR removal: GnRH) or 5d CIDR-Heatsynch (d-5: CIDR + GnRH; d0: PGF2α+CIDR removal; 24 h post-CIDR removal: estradiol benzoate) group. All the buffaloes inseminated at 72 and 84 h post-CIDR removal. A subset of buffalo (n = 58) were subjected to examination of the follicle diameter and luteal profile during protocol, post-AI on days 5 and 12. The buffalo in 5d CIDR-Heatsynch had greater (p < .05) E2 concentrations, estrus induction and increasing trend (p < .08) for conception rate (57.7% vs. 43.6%) than 5d CIDR-Cosynch. The percentage of pregnant buffalo that exhibited estrus signs was greater (p < .01) in 5d CIDR-Heatsynch than 5d CIDR-Cosynch. Positive correlation (p < .01) was observed between POF and E2 concentrations; POF and CL diameter, CL diameter and P4 concentrations. Estrus response and P4 concentrations were indicators of probability of pregnancy. In conclusion, 5d CIDR-Heatsynch tended to improve conception rate. The estrus expression and P4 concentrations (d5 and 12 post-first-AI) is the indicator of probability of pregnancy in buffalo.

Dominant follicles development and estradiol-17β concentrations in non-ovulating and ovulating post-partum Bulgarian Murrah buffaloes

This study was designed to evaluate the dominant follicles development and the estradiol-17β concentrations in non-ovulating and ovulating post-partum buffaloes. Sixteen Bulgarian Murrah buffaloes were submitted to transrectal ultrasonographic examination from the 1st post-partum day until day 50, 3 days apart. The follicular diameter of the different categories of follicles and the ovulations was recorded. The animals were allocated into two groups: I (n = 6) non-ovulating and II (n = 10) ovulating buffaloes. Serum estradiol-17β concentrations on the days for dominant follicle registration were measured by enzyme-linked immunosorbent assay. The results were statistically processed by analysis of variance, non-parametric and correlation analysis. The mean intervals between calving and first dominant follicle detection differed significantly (p < .05) among the groups (19.5 ± 6.2 vs. 13.8 ± 5.1 days), while the mean intervals between registered dominant follicles from two successive waves were comparable. The mean follicular diameters for the same category follicles in both groups were similar. Different estradiol-17β concentrations (p < .05) for the first dominant follicle between non-ovulating (23.5 ± 7.0 pg/ml) and ovulating (33.3 ± 8.4 pg/ml) buffaloes were determined. The cumulative percentages of buffaloes with firstly detected dominant follicle and ovulating animals correlated positively (r ≥ .84; p < .05) to post-partum days. In conclusion, non-ovulating and ovulating post-partum Bulgarian Murrah buffaloes showed differences in the development of the first dominant follicle and estradiol-17β concentrations during the time of dominant follicles detection.

Follicular size predicts success in artificial insemination with frozen-thawed sperm in donkeys

In asses, semen collection, cryopreservation, and artificial insemination (AI) with frozen-thawed semen have been scarcely described and success rate, particularly following AI, is reportedly low. In the absence of reliable protocols, assisted reproductive technologies cannot support the conservation efforts aimed at endangered wild ass species and domestic donkey breeds. Two experiments were conducted in this study. In experiment 1 we evaluated freezing Abyssinian donkey (N = 5, 4 ejaculates each) spermatozoa using three freezing extenders (Berliner Cryomedium + glycerol, BC+G; BotuCrio, BOTU; INRAFreeze, INRA) and two cryopreservation techniques (liquid nitrogen vapour, LNV; directional freezing, DF). Post-thaw evaluation indicated that BOTU and INRA were similar and both superior to BC+G (P ≤ 0.004 for all motility tests), and that DF was superior to LNV (P < 0.002 for all evaluation parameters). In experiment 2, relying on these results, we used Abyssinian donkey sperm frozen in BOTU and INRA by DF for AI (N = 20). Prior to AI, thawed samples were diluted in corresponding centrifugation media or autologous seminal fluids at 1:1 ratio. No difference was found between BOTU and INRA or between the addition of seminal fluids or media, all resulting in ~50% pregnancy, and no differences were noted between males (N = 4). The size of pre-ovulatory follicle was a significant (P = 0.001) predictor for AI success with 9/10 pregnancies occurring when follicular size ranged between 33.1-37.4 mm, no pregnancy when it was smaller, and only one when larger. A number of ass species face the risk of extinction. Knowledge gained in this study on the Abyssinian donkey can be customised and transferred to its closely related endangered species and breeds.

Mastitis outcomes on pre-ovulatory follicle diameter, estradiol concentrations, subsequent luteal profiles and conception rate in Buffaloes

The objectives of this study was to investigate the outcome of mastitis, in its clinical or subclinical forms, on the mean diameter of pre-ovulatory follicle (POF), plasma estradiol concentration on the day of estrus, subsequent luteal profile and subsequent conception rate in buffaloes. Sixty dairy buffalo (Bubalus bubalus) conducted in this study were divided into three groups {healthy (H), n=20; subclinical mastitis (SCM), n=18; and clinical mastitis (CM), n=22}. Ultrasonography of ovaries revealed that mean diameter of POF was larger (P<0.05) in H buffalo (14.35mm) compared to SCM (12.40mm) and CM (10.25mm). Also, plasma estradiol concentration on the day of estrus was higher (P<0.05) in H buffalo compared to SCM and CM counterparts; 34.95 vs. 32.87 and 27.50pg/ml, respectively. Besides, positive correlation was observed between the POF diameter with plasma estradiol concentration in H, SCM and CM buffaloes (r=0.64, 0.74, 0.72 respectively, P<0.05). Moreover, positive correlations (P<0.01) were found on days 9, 12, 16, and 21 post-ovulation between POF diameter and luteal profile. Thus, the conception rate in H buffalo was higher (P<0.05) compared with SCM and CM counterparts; 55% vs. 38.89 and 18.18%, respectively. In conclusion, mastitis in its clinical or subclinical forms disrupts the functioning of the pre-ovulatory follicle on the day of estrus, associated with low follicular estradiol production, resulting in suppression to subsequent luteal profile leading to substantial decrease in pregnancy consequence of buffaloes.

Effect of mastitis on luteal function and pregnancy rates in buffaloes

The aim of this study was to investigate the effects of mastitis on CL development and function and pregnancy rate in buffaloes. Sixty-six buffaloes (Bubalus bubalus) reared in a commercial farm at El-Beheira governorate, north of Egypt were used in this study. According to the visual observation of milk, physical examination of the udder and actual somatic cell count in milk, buffalo cows were divided into three groups: without mastitis (W), n = 23; subclinical mastitis (SC), n = 18; and clinical mastitis (C), n = 25. All buffalo cows were synchronized by double dose of PGF2α (11-day interval) and inseminated by frozen-thawed semen of fertile bull. Mean CL diameter was ultrasonically examined on Days 5, 9, 12, 16, 21, and 25 after artificial insemination (AI). Blood samples were taken on the days of ultrasonography for progesterone (P4) assay. Results indicated that pregnancy rates were lower (P < 0.05) in C (28.00%) and SC (55.56%) compared with W (69.57%) on Day 25 after first AI. Pregnancy rates reduced to 60.87%, 44.45%, and 16.00% in W, SC, and C, respectively, at Day 45 after insemination. Thus, the embryonic loss was 8.7%, 11.11%, and 12.00 % in W, SC, and C cows, respectively. Pregnancy rates decreased between 44.32% and 50.51% when mastitis occurred during Day -15 before to Day +30 after AI, compared with 59.22% in the uninfected cows. The diameter of CL was greater (P < 0.05) in W than SC and C cows starting at Day 9 postbreeding onward. Likewise, P4 concentrations on Days 9 through 25 after AI were greater (P < 0.05) in W cows as compared to SC and C cows. Positive correlations (P < 0.01) were found on Days 5, 9, 12, 16, 21, and 25 after AI between CL diameter and P4 concentrations. Similar trend was found among CL diameter, P4 concentrations, and pregnancy rate. Accordingly, incidence of mastitis revealed suppression to both CL diameter and function leading to significant reduction in pregnancy outcome of buffalo cows.

Endometritis impairs luteal development, function, and nitric oxide and ascorbic acid concentrations in buffalo (Bubalus bubalis)

A vast majority of the world buffalo resource is concentrated in tropical and subtropical countries. Apart from heat stress and poor nutritional availability, endometritis is one of the most commonly encountered reproductive problems limiting fertility and consequently productive potential of the species. As demonstrated recently, endometritis impairs growth and follicular fluid composition of the largest follicle in buffalo. In the present study, the effect of endometritis on luteal development, function, nitric oxide (NO), and ascorbic acid was investigated. Reproductive tracts were collected from 90 cyclic buffaloes at an abattoir and grouped into endometritic (n = 36) or non-endometritic (n = 54) buffaloes based on physical examination of uterine mucus, white side test, and uterine cytology. Samples with pus-containing mucus, positive reaction on white side test, and/or >5 % neutrophils were considered to be positive for endometritis. Corpora lutea were enucleated, weighed, classified into stages I to IV, and assayed for progesterone (P(4)), NO, and ascorbic acid concentrations. Endometritic buffaloes had lesser (P < 0.0001) luteal weight and P(4), NO, and ascorbic acid concentrations than non-endometritic buffaloes. The findings indicated that endometritis impairs corpus luteum development and function in buffalo. Reduced luteal NO and ascorbic acid concentrations during endometritis are novel findings.