Evaluation of reproductive tract infection during early post-partum period and its relationship with subsequent reproductive performance in high milk producing dairy cows

Clinically normal Holstein‐Friesian cows (n = 43) were used to establish a relationship between the evaluations of the uterine condition by vaginoscopy, Metricheck, endometrial cytology (EC) and ultrasonography (US) during post‐partum period (pp), and subsequent reproductive performance. The uterine status of the selected cows was evaluated by EC, Metricheck, US and vaginoscopy on a weekly basis from the third week (W3) to the seventh week (W7) pp. The animals were bred after a voluntary waiting period of 45–60 days pp and diagnosed for pregnancy status at 45 days after breeding by US. First service conception rate (FSCR) of bred animals was 32.6% (14/43). There was no significant difference in polymorphonuclear leucocyte percentage between conceived and non‐conceived cows during different weeks post‐partum. First service conception rate in animals with normal vaginal discharge as detected by Metricheck was significantly low when compared to those of abnormal discharge during W3 (2.3% vs 30.3%; p < 0.001) and W4 (4.7% vs 29.7%; p < 0.01) post‐partum. Using US, the number of pregnant cows having fluid in uterus (FIU) during W6 (p < 0.01) and W7 (p < 0.001) post‐partum was significantly lower (2/34, 4.7% and 1/43, 2.3%, respectively) than those that had no FIU (12/43, 27.9% and 13/43, 30.3%, respectively). Using vaginoscopy, FSCR in animals having abnormal discharge was significantly (p < 0.01) low when compared to that of normal discharge (2.4% vs 30.2%) during W5 and W6 post‐partum. In conclusion, Metricheck during W3 and W4 and detection of FIU by US and vaginoscopy during W6 and W7 pp can be used as good predictive tools to anticipate the future reproductive performance of dairy cattle.     

Influences of metabolic traits on subclinical endometritis at different intervals postpartum in high milking cows

Seventy pluriparous high‐yielding cows were used to investigate the impact of metabolic traits and body condition score (BCS) during early lactation on subclinical endometritis diagnosed at weeks 5, 6 and 7 postpartum (pp). Blood samples were collected from animals with no peripartum problems from the second (W2) to seventh (W7) weeks pp to estimate some blood metabolites including non‐esterified fatty acids (NEFA), β‐hydroxybutyric acid (BHBA), blood glucose, total cholesterol (T‐chol) and blood urea nitrogen (BUN). Reproductive tract examination was carried out at weeks 5, 6 and 7 pp by endometrial cytology (percentage of polymorphonuclear cells; PMN%). Based on PMN%, animals having <5% were defined as subclinical endometritis group (ENDM group) while animals unaffected by endometritis were defined as no subclinical endometritis group (NOENDM group). Animals with endometritis during week 5 were identified as ENDM5, during week 6 identified as ENDM6 and during week 7 identified as ENDM7 or animals with no endometritis during weeks 5 (NOENDM5), 6 (NOENDM6) and 7 (NOENDM7) pp. Animals diagnosed at week 5; BUN and BCS were lower p < 0.05 in ENDM 5 than NOENDM5 group at W2, W4, W6 and W7. Cows diagnosed at week 6; T‐chol was significantly higher (p = 0.05) in ENDM6 group (279.2 ± 12.5 mg/dl) than NOENDM6 group (246 ± 9.5 mg/dl) at W7. Moreover, blood glucose was significantly low (p < 0.05) in ENDM6 group when compared to NOENDM group at W4 pp (49.2 ± 1.8 vs 53.8 ± 1.3 mg/dl). BCS was significantly lower (p < 0.001) in animals suffered from endometritis during week 7 when compared to NOENDM7 cows at W3, W4, W5, W6 and W7. In conclusion, lower blood glucose, BUN and BCS could be a risk factor for cytologically diagnosed endometritis at weeks 5, 6 and 7 pp.     

Follicular progesterone levels decrease during the period of seasonal infertility in sows

Impaired reproductive performance exhibited by the domestic sow during the late summer and early autumn months is referred to as seasonal infertility. This study was carried out to determine whether there are changes in ovarian morphology and follicular steroidogenesis associated with season, which may be associated with seasonal infertility. Ovaries were collected in pairs from sows sourced from two farms and slaughtered 4 days after weaning during winter and summer. The mean progesterone concentration in follicular fluid (FF) collected from small follicles was lower in summer (701.3 ± 115.54 nm) compared with winter (1235.55 ± 164.47 nm; p<0.001). The mean progesterone concentration in the FF of large follicles was also lower in summer (1469.2 ± 156.51 nm) compared with winter (2470.9 ± 169.13 nm; p<0.001). The number of large surface antral follicles (5-8 mm in diameter) on the ovaries recovered from Farm A sows was higher during summer (17.76 ± 0.56) than in winter (15.38 ± 0.54; p<0.05). Similarly, the number of small follicles (3-4 mm in diameter) on Farm A sow ovaries was higher in summer (8.46 ± 0.66) than in winter (4.63 ± 0.53; p<0.001). In contrast, the number of small follicles on the surface of ovaries recovered from Farm B sows was higher during winter (10.17 ± 1.50) than in summer (6.45 ± 1.00; p<0.01). The number of pre-ovulatory follicles (>8 mm in diameter) was also higher in winter (1.23 ± 1.68) when compared to summer (0.51 ± 0.3; p<0.001) on the ovaries of sows from Farm B. The results suggest that there are seasonal differences in follicular steroidogenesis and ovarian dynamics. These findings add support to the theory that altered follicular steroidogenesis and ovarian morphology may possibly be the mechanism behind reduced reproductive performance during the period of seasonal infertility in sows.     

Distribution and Heterogeneity of Mast Cells in Female Reproductive Tract and Ovary on Different Days of the Oestrus Cycle in Angora Goats

The physiological distribution of mast cells (MCs) in the reproductive tract and ovary of 12 Angora goats was determined using light microscopic histochemical techniques. Uterus (corpus uteri and cornu uteri), uterine cervix, uterine tubes (isthmus and ampulla) and ovary samples were obtained by laparatomy from groups of animals during metoestrus, dioestrus and proestrus (days 5, 10 and 16 of the oestrous cycle). Tissues were fixed in Mota's fixative (basic lead acetate) for 48 h and embedded in paraffin. Six-micrometre-thick sections were stained with toluidine blue in 1% aqueous solution at pH 1.0 for 5 min and alcian blue-Safranin at pH 1.0 for 30 min. MCs were generally associated with blood vessels in all reproductive organs. In the uterus, they were concentrated mainly in the close of the uterine gland and deep stroma in the endometrium. Higher MC numbers were observed by toluidine blue staining in the uterus, uterine cervix and uterine tubes on days 10 (corpus uterine: 4.7 ± 3.8 and cornu uterine: 4.9 ± 3.5) and 16 (corpus uterine: 5.9 ± 4.5 and cornu uterine: 5.4 ± 2.4) of the oestrous cycle compared with day 5 (p < 0.05). Mast cells were not observed in the follicles, the corpus luteum and the underside of the surface epithelium of the ovarian cortex, but were observed in the interstitial cortical stroma and the ovarian medulla. In the ovary, MC numbers were significantly higher on day 16 of the oestrous cycle (cortex: 3.4 ± 2.4 and medulla: 5.7 ± 4.5, p < 0.05). Safranin-positive connective tissue MCs were not observed in the uterine tube on any occasion. These results indicate oestrous cycle-related changes in the number and location of MCs in goat reproductive organs.     

Formation of Corpora Lutea and Central Luteal Cavities and Their Relationship with Plasma Progesterone Levels and Other Metabolic Parameters in Dairy Cattle

The corpus luteum (CL) may be looked upon as a compact or cavitary structure. A number of papers have addressed the relationship between CL type and parameters such as fertility or progesterone levels. The present study assessed the morphological and functional sequence observed in cows with different CL types, comparing pre-ovulatory follicle size, progesterone levels, luteal tissue formation and some blood biochemical parameters (calcium, albumin, inorganic phosphorus, glucose, magnesium, copper and zinc), oestrus cycle length and oestrus expression, as a function of CL type. Twenty-eight lactating dairy cows from two commercial dairy farms in southern Spain were studied. Oestrus detection was performed by monitoring daily oestrus behaviour, and artificial insemination (AI) was perfomed using the AM/PM rule. Ovaries and uterus were sonographically examined and blood samples were collected to measure progesterone and various biochemical parameters. There was a slight tendency towards the appearance of luteal cavities when pre-ovulatory follicles were larger (1.9 ± 0.2 vs 1.7 ± 03; p = 0.074). Fertility was not affected by cavity presence (cavity = 42.9% and compact = 57.1%; n.s.). Luteal tissue and function were not modified as a function of CL type. Cows with luteal cavities displayed significantly higher levels of albumin, suggesting a possible metabolic influence on the formation of these structures, although specific research is required to confirm this observation.     

Bovine Uterine,Cervical and Ovarian Cytosol Estrogen and Progesterone Receptor Concentrations in Cystic Ovarian Disease

Bovine cytosol estrogen (ERC) and progesterone receptor (PRC) concentrations were measured simultaneously in various regions of the uterus and in ovarian stromal tissue in cows with cystic ovarian disease (follicular cysts), arid the concentrations compared with those in animals with normal cycles. In cystic ovarian disease, ERC concentrations in endometrium (550 fmol/mg cytosol protein (c.p.)) and in myometrium (405) were significantly higher than in control animals. Very high PRC contents were measured in the endometrium (3115) and myometrium (2761) of cows with cystic ovarian disease. In control animals, PRC concentrations in the endometrium and myometrium were significantly lower than in diseased animals. No statistical differences were observed in ERC or PRC contents between the endometrium and the myometrium in cows with cystic ovarian disease. ERC and PRC concentrations in the uterine cervix and ovaries were low compared to those detected in the uterus. Bovine serum estradiol-17ß concentrations were higher (p<0.001) in cows with cystic ovarian disease than in control animals in postpartum anestrus or during the normal estrous cycle. Serum sex hormone-binding globulin (SHBG) concentrations were of the same magnitude as in control cows during their estrous cycles. These findings show that long standing low endogenous progesterone and elevated estradiol concentrations in serum are associated with elevated ERC and PRC concentrations in bovine uterus.     

Cystic Degeneration in Porcine Ovaries - First Communication: Morphology of Cystic Ovaries, Interpretation of the Results

Contents: The morphological appearance of ovarian structures in 79 sows with ovarian cysts was examined. Sixty sows had been culled due to sterility; 19 sows had been repeatedly investigated clinically before slaughter. It was found that cystic ovaries without corpora lutea (CL) had the largest diameter and volume (151.3 cm³), in comparison to both cystic ovaries with CL (85.7 cm³) and normalovaries (16.9 cm³). The number of cysts on ovaries without corpora lutea was approximately twice as high as on the ovaries with CL (23.3 vs 12.1 cystslsow; p < 0.001). A combined form of degeneration consisting of large (> 1.5 cm in diameter) and small (1.5 em in diameter) cysts was found in 63% of the animals, whereas degeneration with only small cysts occured in 8% of the cases. Dark CL, interpreted as being functional, were mainly present in animals with up to 10 cysts per sow (24 out of 27 sows, p < 0.001); pale CL, interpreted as being weakly functional, were mainly found on ovaries with more than 10 cysts (19 out of 23 sows; p < 0.001). Based on macroscopical differentiation cyclic activity was found to be dependent to the number of cysts. Regular or irregular estrous cycles were observed in oligocystic animals (10 cysts/animal) with functional CL (58%). Up to 75% of the animals with pale or absent CL showed no estrous activity.     

Induction of Ovulation of Ovulatory Size Non‐Ovulatory Follicles and Initiation of Ovarian Cyclicity in Summer Anoestrous Buffalo Heifers (Bubalus bubalis) Using Melatonin Implants

This study was conducted on summer anoestrous buffalo heifers to monitor the efficacy of melatonin for induction of ovulation and ovarian cyclicity. During pre‐treatment period of 24 days, the ovarian dynamics of five cycling and 10 summer anoestrous heifers was monitored on each alternate day using a transrectal ultrasound scanner. Thereafter, during treatment period, these 10 anoestrous heifers along with additional seven anoestrous heifers were randomly allocated into non‐implanted (n = 5) and implanted (n = 12, one melatonin implant/50 kg, 18 mg melatonin/implant) group. Non‐implanted heifers were monitored on each alternate day till the confirmation of second‐ovulation in implanted heifers. Pre‐treatment period revealed the presence of dominant follicles in anoestrous heifers which attained the diameter comparable with ovulatory follicles of cycling heifers but failed to ovulate and regressed. Between 6 and 36 days (15.3 ± 2.9 days) post‐treatment, all the implanted heifers (p < 0.05) exhibited ovulation of dominant follicles; however none of the non‐implanted heifers ovulated during the corresponding period. The first‐interovulatory period in implanted heifers ranged between 8 and 28 days (18.0 ± 1.8 days). The implanted heifers with short (≤16 days) interovulatory period had short‐lived corpus luteum (CL) that had smaller diameter and secreted less progesterone (p < 0.05). The diameter of CL was large (p < 0.05) and plasma progesterone was high (p < 0.05) following second‐ovulation compared with first‐ovulation in implanted heifers. In conclusion, using melatonin implants, ovulatory size nonovulatory follicles observed in summer anoestrous buffalo heifers can be successfully ovulated to initiate ovarian cyclicity.     

Evaluation of vaginal discharge with the Metricheck device and the relationship to reproductive performance in postpartum dairy cows

Vaginal mucus during estrus was examined with the Metricheck device and the relationship to the reproduction of high‐yielding dairy cows was studied. The study was conducted in 99 dairy herds located in Western Germany and 1348 Holstein‐Friesian heifers and cows showing spontaneous estrus were examined. Independent of the Metricheck result, the animals were inspected by professional insemination technicians and those suitable for insemination (n = 989) were bred by artificial insemination (AI). Reproductive performance was characterized by non‐return rate at 90 days (NRR90). The discharge of the animals predominantly had a clear appearance (70%) and a stringy consistency (80%). Animals with clear vaginal discharge had higher NRR90 (56%; n = 697) than animals with abnormal (turbid, mucopurulent, purulent, sanguineous) vaginal secretion (48%, n = 292; P < 0.05). NRR90 was lower in animals with short calving to AI interval (< 70 days; 39%) than with medium (70–130 days; 54%) or long (> 130 days; 62%) intervals (P < 0.05). NRR90 decreased by 12% from the lowest (< 15 kg) to the highest (> 45 kg) milk yield class. In conclusion, the use of the Metricheck device integrated into the insemination procedure is recommended to identify dairy cows suffering severely from uterine disease.     

Adequacy of main uterine vein and the ovarian artery in the local venoarterial pathway for uterine-induced luteolysis in ewes.

The local uteroovarian pathway for uterine-induced luteolysis was studied in 34 ewes. Bilaterally ovulating ewes were used to study the role of the main uterine vein (uterine branch of uteroovarian vein) and unilaterally ovulating ewes were used to study the role of the ovarianartery. Surgical operation was done on day 7, 8, or 9 of diestrus and ewes were necropsied on day 20. In 4 bilaterally ovulating control ewes (unilaterally hysterectomized), mean weight of corpus luteum (CL) was less (P smaller than 0.05) on the side of the intact uterine horn (55 mg) than on the side of unilateral hysterectomy (548 mg). In 4 treated ewes (unilaterally hysterectomized and with surgical anastomosis of uterine vein from the intact side to the hysterectomized side), mean weight of CL on the hysterectomized side (153 mg) was less (P smaller than 0.05) than on the uterine-intact side (391 mg). The mean weight of CL on the hysterectomized side in the treated group was not significantly different from that of the uterine-intact side in the control group. Unilaterally ovulating ewes were randomized into 5 groups: (1) controls which were uterine intact, (2) controls in which a unilateral hysterectomy was done ipsilateral to CL, (3) unilateral hysterectomy done ipsilateral to CL and anastomosis of the ovarian branch of the ovarian artery on the uterine-intact side to the ovarian branch of the ovarian artery on the hysterectomized side, (4) controls in which unilateral hysterectomy was done contralateral to CL and the ovarian vascular pedicle on the uterine-intact side was isolated, and (5) unilateral hysterectomy done contralateral to CL, isolation of ovarian vascular pedicle on the uterine-intact side, and anastomosis of the ovarian branch of the ovarian artery on the unilaterally hysterectomized side to the ovarian branch of the ovarian artery on the uterine-intact side. Mean weight of CL was less (P smaller than 0.05) in groups 1 (56 mg), 3 (40 mg), and 4 (120 mg) than in groups 2 (408 mg) or 5 (473 mg). The mean weight of CL was not significantly different among groups 1, 3, and 4 or between groups 2 and 5. Results demonstrate that the local luteolytic effect of the uterus in ewes involves a venoarterial pathway and indicate that the main uterine vein is an adequate uterine outlet and the ovarian artery is an adequate ovarian inlet for the venoarterial pathway without the necessity of other possible concomitant local routes.     

Light microscopical and ultrastructural characterization of black howler monkey (Alouatta caraya) ovarian follicles

The present study describes the morphological characteristics of black howler monkey (Alouatta caraya) ovarian follicles. One ovary of an adult healthy black howler monkey was collected and processed for light and electron microscopy. Primordial, primary, secondary, tertiary and pre-ovulatory follicles were evaluated for their morphometrical aspects. The ovary of black howler monkey presented a distinct conformation with a uniform distribution of the follicles mostly in the peripheric cortex. This black howler monkey ovary presented a total of 59 921 ovarian follicles. From this amount, 71.1% were classified as primordial, 18.9% as primary, 8.1% as secondary, 1.4% as tertiary and 0.5% as pre-ovulatory follicles. From all these developmental stages, the mean diameters of follicles, oocytes, oocytes nuclei and the mean number of granulosa cells are described. Moreover, primordial, primary and secondary follicles have been observed by electron microscopy.     

Uterine Infection Influences Size and Follicular Fluid Composition of the Largest Follicle in Buffalo (Bubalus bubalis)

The effect of uterine infection on size and follicular fluid composition of the largest follicle was studied in buffalo. Reproductive tracts were collected from 102 graded Murrah buffaloes at an abattoir. Uterine infection was diagnosed by 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 uterine infection. Diameter of the largest follicle was measured, and follicular fluid was aspirated and assayed for nitric oxide (NO), ascorbic acid (AA), cholesterol, oestradiol (E₂) and progesterone (P₄). Infected buffaloes had smaller‐sized (p < 0.0001) largest follicles than non‐infected buffaloes. Follicular fluid collected from the largest follicle in infected buffaloes had greater (p < 0.0001) NO and P₄ concentrations coincident with lesser AA (p < 0.001), cholesterol (p < 0.0001) and E₂ (p < 0.0001) concentrations. Results indicated that uterine infection has an inhibitory effect on growth of the largest follicle in buffalo. The changes in follicular fluid composition in infected buffaloes suggest that the direct effect of uterine infection on ovarian function may be mediated through an alteration in the follicular microenvironment. Greater NO and lesser AA concentrations in the follicular fluid of infected animals are novel findings.     

Assessment of early postpartum reproductive performance in two high producing Estonian dairy herds

Early postpartum (6 weeks) ovarian activity, hormonal profiles, uterine involution, uterine infections, serum electrolytes, glucose, milk acetoacetate and blood urea nitrogen (BUN) levels were studied in 2 Estonian high producing dairy herd with annual milk production of 7688 (Farm A) and 9425 (Farm B). From each farm 10 cows, with normal calving performance were used. Blood samples for the hormonal (PGF2alpha-metabolite, progesterone) analyses were withdrawn. On day 25 PP blood serum samples were taken for the evaluation of metabolic/electrolyte status. On the same day estimation of milk acetoacetate values was done. The ultrasound (US) was started on day 7 PP and was performed every 3rd day until the end of experiment. Uterine content, follicular activity and sizes of the largest follicle and corpus luteum were monitored and measured. Vaginal discharge and uterine tone were recorded during the rectal palpation. Each animal in the study was sampled for bacteriological examination using endometrial biopsies once a week. Two types of PGF2alpha-metabolite patterns were detected: elevated levels during 14 days PP, then decline to the basal level and then a second small elevation at the time of final elimination of the bacteria from the uterus: or elevated levels during first 7 days PP, then decline to the basal level and a second small elevation before the final elimination of bacteria. Endometritis was diagnosed in 5 cows in farm A and in 3 cows in farm B respectively. In farm A, 5 cows out of 10 ovulated during experimental period and in 1 cow cystic ovaries were found. In farm B, 3 cows out of 10 ovulated. In 3 cows cystic ovaries were found. Altogether 40% of cows had their first ovulation during the experimental period. Three cows in farm A and 5 cows in farm B were totally bacteria negative during the experimental period. The most frequent bacteria found were A. pyogenes, Streptococcus spp., E. coli., F. necrophorum and Bacteroides spp. The highest incidence of bacteriological species was found during the first 3 weeks in both farms. All animals were free from bacteria after 5th week PP in farm A and after 4th week in farm B respectively. Serum electrolytes and glucose levels were found to be within the reference limits for the cows in both farms. No significant difference was found between farms (p > 0.05). Low phosphorus levels were found in both farms. Significant difference (p < 0.05) was found in BUN levels between farms. In both farms milk acetoacetate values were staying within the reference range given for the used test (< 100 micromol/l). The uterine involution and bacterial elimination in the investigated cows could consider as normal but more profound metabolic studies could be needed to find reasons for later resumption of ovarian activity. Some recommendations to changing feeding regimes and strategies should also be given.     

Relationships between uterine length and number of fetuses and prenatal mortality in pigs

Relationships between the length of uterine horn and number of fetuses and prenatal mortality were characterized in 320 pregnant pigs at 3, 5, 7, 9, 11, 13 and 15 wk of gestation in a cross-sectional design. Genital tracts of all pregnant animals available on the days of collection were measured. Length of each uterine horn, numbers of fetuses and corpora lutea (CL) were recorded and prenatal mortality was calculated. With each additional fetus, length of the uterus increased 10 cm regardless of stage of gestation (P less than .001). The association of number of fetuses and uterine length was local and confined to that horn in which the fetus resided and did not extend to the opposite horn. As number of CL increased, number of fetuses also increased as did prenatal mortality. There was a significantly negative correlation between uterine length and prenatal mortality when animals were classified into four groups on the basis of number of CL; less than 10, 10 to 14, 15 to 18 and greater than 18. Results indicated that the number of fetuses and prenatal mortality were closely correlated with length of the uterus. Length of the uterus appeared to be an important limiting factor to litter size as number of CL increased.     

Expression of estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta) in the ovarian follicles and corpora lutea of pregnant swine

The objective of the study was to demonstrate the presence of estrogen receptor alpha (ERalpha) and beta (ERbeta) protein and corresponding mRNA in porcine ovarian follicles and corpora lutea obtained on day 10, 18, 32, 50, 71 and 90 post coitum (p.c.) using immunohistochemistry, Western blot, and RT-PCR analysis. Immunohistochemistry showed that ERalpha protein was located in the granulosa cells of ovarian follicles and the strongest immunoreaction was observed on days 32 and 50 p.c. The ERbeta protein was found mainly in theca cells of follicles as well as in luteal cells. The most intense immunoreaction was observed on day 18 p.c. within theca cells, while in the corpus luteum (CL) the intensity of ERbeta staining gradually increased and remained elevated at mid and late pregnancy. In CL by day 50 p.c. immunoreaction for ERbeta was present only in small luteal cells, but starting from day 71 to 90 p.c. it was observed in both small and large luteal cells. Western blot analysis was performed and validated data obtained from immunohistochemistry. RT-PCR results indicated that ERalpha mRNA was expressed only in ovarian follicles of the pregnant swine, while that of ERbeta in both follicles and CL. The results suggest an autocrine/paracrine role of estrogens acting via both ERalpha and ERbeta in the regulation of the ovarian function during pregnancy and for the process of successful reproduction.     

The ovulatory response of anoestrous goats exposed to the male effect in the subtropics is unrelated to their follicular diameter at male exposure

This study was designed to determine whether the follicular diameter at the introduction of the bucks influences the ovarian response in does exposed to males during the anoestrous season in the subtropics. Bucks (n = 4) were subjected to 2.5 months of long days from November 1st to stimulate their sexual activity. On 29th March, one of the four treated males was joined with the females (n = 13), being exchanged with other males every 12 h, during 10 days. Oestrous behaviour was recorded twice daily. Ultrasound examinations of the ovaries were performed once daily from Day -7 to -1 and twice daily from Day 0 to 6. Follicles that ovulate were categorized according to the diameter at the moment when females were joined with males, as Small (<3.9 mm), Medium (4.0-5.9 mm) or Large (>6.0 mm). All females ovulated (13/13) and 12 came into oestrus during the first 5 days after exposure to males. The growth rate of the follicles increased after the introduction of the bucks from 1.1 ± 0.1 mm per day to 1.5 ± 0.1 mm per day (p < 0.05). The percentage of follicles from each category that ovulated did not differ (p > 0.05; Small 47.8%; Medium 34.8% and Large 17.4%). From follicles that ovulated, the growth rate of those that were Small at the moment of the introduction of the bucks was greater (2.1 ± 0.1 mm per day; p < 0.05) than that observed in those that were Medium (1.3 ± 0.1 mm per day) and Large follicles (1.1 ± 0.1 mm per day). In 12 does, the largest follicle present in the ovaries was growing when bucks were introduced. From these follicles, five finally ovulated and seven finally regressed. In conclusion, the follicular diameter at the introduction of the bucks is not related to the oestrous behaviour and ovulatory responding patterns in female goats exposed to sexually active bucks in the subtropics.     

A potential use of color ultrasound as a tool for reproductive management: New observations using color ultrasound scanning that were not possible with imaging only in black and white

Ultrasonography (US) has been applied to the ovary and the uterus of domestic animals from the late 1980s, and established in 1990s as a practical tool for animal production. US made it possible to detect pregnancy at a very early stage and, most importantly, to observe the real-time dynamics of follicular development and hence the discovery of follicular waves. This has greatly contributed to our understanding of ovarian physiology and helped us to develop several "pin-point" protocols for hormonal treatment. While US may not seem to fit preconceived ideas of a "green" technology, it does not contravene environmental priorities, and it is non-invasive ("ethical") and non-hormonal ("clean"). Using the US technology that is now commercially available at a reasonable price, we are able to estimate the best timing for AI and this allows us to plan either the use of precisely-timed nutritional supplements for fetal development or an immediate 2nd AI service to achieve a better economic efficiency. During the last few years, we have also begun to be able to observe in detail the local blood flow in individual ovarian follicles and CL using color Doppler ultrasonography in the cow. From the series of observations, we have found that: 1) the change of blood supply to an individual follicle closely relates to the dynamics of follicular growth and atresia; 2) the local blood flow detected in the theca externa of mature follicles rapidly increases around the onset of LH surge and is most active before ovulation; 3) the blood supply to the developing CL increases in parallel with CL volume and plasma progesterone concentrations; and 4) the local blood flow surrounding the mature CL acutely increases prior to the onset of luteolysis in response to uterine as well as exogenous PGF(2alpha). It is now clear that color Doppler ultrasound is very useful for observing echogenicity with local blood flow thereby providing an easily obtained estimation of the physiological status of follicles, CLs and early conceptus. Widespread commercial application of color US will depend on further technological developments that reduce the cost and improve performance and ease-of-use. Overall, US is now a most effective non-invasive tool for managing reproduction, at the level of both the individual animal and the herd system. In particular, US can help us to clarify potential problems in high-producing dairy cattle during the postpartum period.     

Suitability of sonographic evaluation of ovarian dynamics and uterine involution for prediction of postpartum fertility in the cow

To investigate the suitability of sonography for prediction of puerperal fertility, we used 34 cows with normal puerperium. For this purpose, the animals were examined gynecologically and by transrectal sonography at 10-day intervals between day 15 and day 45 p.p. as well as at oestrus, when they were inseminated. We judged uterine involution by diameter and sonographic structure of the uterine cross-section and ovarian activity by the presence of follicles and corpora lutea. Cows, which became pregnant after first insemination p.p., were assigned to group G1 (n = 16) and animals, which failed to conceive, to group G2 (n = 18). The cows of G1 obtained significantly better results concerning both uterine involution and ovarian activity than cows of G2. Thus, diameter of the uterine horn decreased faster and sonographic structure of the uterine cross section returned markedly earlier to the nonpregnant appearance in G1 than in G2. Group G1 also showed a significantly higher percentage of dominant follicles at all examinations. The results of the study show a distinct relationship between uterine involution and ovarian activity and puerperal fertility. But it has also to be resumed that the prediction of fertility for individuals will always be restricted by other reasons causing failure of conception.     

Evidence for a potential role of neuropeptide Y in ovine corpus luteum function

Neuropeptide Y (NPY) is a neurohormone that is typically associated with food intake, but it has also been reported to affect the production of progesterone from luteal tissue in vitro. However, NPY has not been previously immunolocalized in the ovine ovary or in the corpus luteum (CL) of any species, and the effects of this neurohormone on luteal function in vivo are not known. Thus, we performed fluorescent immunohistochemistry (IHC) to localize NPY in the ovine ovary and used avidin-biotin immunocytochemistry (ICC) to further define the intracellular localization within follicles and the CL. We then infused NPY directly into the arterial supply of the autotransplanted ovaries of sheep to determine the in vivo effect of exogenous NPY on ovarian blood flow and on the luteal secretion rate of progesterone and oxytocin. Immunohistochemistry revealed that the NPY antigen was localized to cells within the follicles and CL, in the nerve fibers of the ovarian stroma, and in the vessels of the ovarian hilus. In the follicle, the NPY antigen was localized to nerves and vessels within the theca interna layer, and strong staining was observed in the granulosal cells of antral follicles. In the CL, NPY was localized in large luteal cells and in the vascular pericytes and/or endothelial cells of blood vessels, found dispersed throughout the gland and within the luteal capsule. In vivo incremental infusions of NPY at 1, 10, 100, and 1,000 ng/min, each for a 30-min period, into the arterial supply of the transplanted ovary of sheep bearing a CL 11 d of age increased (P ≤ 0.05) ovarian blood flow. The intra-arterial infusions of NPY also increased (P ≤ 0.05) in a dose-dependent manner the secretion rate of oxytocin, which was positively correlated (P ≤ 0.05) with the observed increase in ovarian blood flow. The infusions of NPY had a minimal effect on the secretion rate of progesterone, and similar intra-arterial infusions of NPY into sheep with ovarian transplants bearing a CL over 30 d of age had no significant effect on ovarian blood flow or on the secretion rate of progesterone. These results suggest that NPY acts on the luteal vascular system and the large luteal cells to rapidly stimulate blood flow and the secretion of oxytocin, respectively, which collectively implies a putative role for NPY during the process of luteolysis when increasing amounts of oxytocin are secreted from the ovine CL in response to uterine pulses of prostaglandin F2α.     

不同月龄绵羔羊卵泡发育的比较研究

本研究旨在比较1、3月龄绵羔羊激素处理后卵巢、子宫及血液中促卵泡激素(FSH)变化,研究不同月龄对羔羊卵泡发育的影响。通过对1、3月龄羔羊进行FSH和孕马血清促性腺激素(PMSG)处理,比较羔羊在激素处理前后血液中FSH水平和卵巢、子宫大小变化,卵巢上2～8 mm卵泡的数量和卵母细胞体外成熟、受精后胚胎的发育情况。结果表明:1月龄羔羊实验组体内整体FSH水平高于3月龄羔羊(P<0.05)。1月龄羔羊注射外源激素后两侧卵巢可获卵母细胞数(42.3±2.5、36.8±1.1)枚及体外受精囊胚发育率(16.33%±0.96%)显著高于3月龄羔羊卵母细胞数(10.0±0.7、8.5±0.6)枚及囊胚率(9.29%±1.55%)(P<0.05)。羔羊进行超数排卵处理时卵巢上卵泡发育与血液中FSH水平密切相关,且较高的FSH水平预示着较多的卵泡发育。