scholarly journals 17 COMPARISON OF FOLLICULAR WAVE EMERGENCE AND FOLLICULAR DEVELOPMENT FOLLOWING ESTRADIOL BENZOATE PLUS PROGESTERONE OR GnRH AT THE FIRST FOLLICULAR WAVE IN A CIDR-TREATED, LACTATING HOLSTEIN COWS

2005 ◽  
Vol 17 (2) ◽  
pp. 158
Author(s):  
U.H. Kim ◽  
G.H. Suh ◽  
I.H. Kim
Keyword(s):  
Follicular Development ◽  
Estradiol Benzoate ◽  
Holstein Cows ◽  
Exact Test ◽  
Follicular Wave ◽  
Array Transducer ◽  
Ovulatory Follicle ◽  
Wilcoxon Rank Sum Test ◽  
Student’S T ◽  
Ovulatory Follicles

Treatment with GnRH in a controlled internal drug release (CIDR)-based timed AI protocol induced synchronized follicular wave emergence, a large ovulatory follicle, and synchronous ovulation following a second injection of GnRH, while follicular wave emergence was relatively asynchronous in the estradiol benzoate (EB)-treated cows resulting in ovulation of smaller ovulatory follicles (Kim et al. 2004 Theriogenology, in press). In this study, we compared new follicular wave emergence and follicular development following treatment with EB plus progesterone (P4) or GnRH at the first follicular wave in CIDR-treated, lactating Holstein cows. Previously synchronized, lactating Holstein cows (n = 20) received a CIDR (CIDR™, InterAg, Hamilton, New Zealand, Day 0) 3 to 8 days after ovulation and were randomly assigned to two treatments: cows in the GnRH group (n = 10) received 100 μg fertirelin acetate i.m. (GnRH, Conceral, Dongbang Co., Seoul, Korea) and those in the E/P group (n = 10) received 2 mg EB (SY Esrone, Samyang, Seoul, Korea) and 50 mg P4 i.m. (SY Ovaron, Samyang, Seoul, Korea) at that time. Thereafter, all animals received PGF2α (Lutalyse, Pharmacia & Upjohn, Puurs, Belgium) at the time of CIDR removal on Day 7, and GnRH on Day 9. Ovaries of each cow were examined by transrectal ultrasonography (Sonoace 600 with 5.0 MHz linear-array transducer; Medison Co., Ltd., Seoul, Korea) every 24 h from Days 0 to 9, on Day 11, and on Day 14 of treatment to observe changes in ovarian structures (follicles and CL). Data were analyzed by Fisher's exact test, Wilcoxon Rank-Sum test and Student's t-test using an SAS program. Follicular wave emergence occurred within 7 days in 9/10 GnRH- and 8/10 E/P-treated cows (P > 0.05). The interval to wave emergence was longer (P < 0.01) in the E/P group (5.9 ± 0.5 days) than in the GnRH group (2.9 ± 0.4 days). While diameters of dominant follicles on Day 0 were not different (P > 0.05) between groups, diameters on Day 7 and Day 9 in the E/P group (9.4 ± 0.4 and 13.1 ± 0.7 mm, respectively) were significantly smaller (P < 0.01) than those in the GnRH group (12.9 ± 0.5 and 15.8 ± 0.7 mm, respectively). Growth rates of preovulatory follicles in the E/P group (2.1 ± 0.2 mm/day) were greater (P < 0.01) than in the GnRH group (1.2 ± 0.1 mm/day), while the duration of dominance of the preovulatory follicle was longer (P < 0.01) in the GnRH group (6.3 ± 0.4 days) than in the E/P group (3.3 ± 0.5 days). Synchronized ovulation by 40 h after the GnRH injection (Day 11) occurred in 10/10 GnRH- and 9/10 E/P-treated cows (P > 0.05). Results suggest that estradiol benzoate plus progesterone administered at the first follicular wave in CIDR-treated, lactating Holstein cows delays new follicular wave emergence, resulting in ovulation of smaller ovulatory follicles than GnRH. Endocrine changes during treatment and fertility following timed AI has been investigated in this study.

235 FOLLICULAR WAVE EMERGENCE AND DEVELOPMENT FOLLOWING ESTRADIOL PLUS PROGESTERONE AT A GROWING OR A STATIC PHASE OF THE DOMINANT FOLLICLE IN CIDR-TREATED, LACTATING DAIRY COWS

2006 ◽  
Vol 18 (2) ◽  
pp. 225
Author(s):  
U. H. Kim ◽  
G. H. Suh ◽  
I. H. Kim
Keyword(s):  
Dairy Cows ◽  
Estradiol Benzoate ◽  
Control Group ◽  
Corpora Lutea ◽  
Dominant Follicle ◽  
Exact Test ◽  
Follicular Wave ◽  
Lactating Dairy Cows ◽  
Array Transducer ◽  
Static Phase

Treatment with estradiol benzoate (EB), compared to GnRH, in a controlled internal drug release (CIDR)-based timed AI protocol induced relatively asynchronous follicular wave emergence, resulting in ovulation of smaller ovulating follicles (Kim et al. 2005 Theriogenology 63, 260-268). In this study, we compared new follicular wave emergence and development following treatment with EB (2 mg) plus progesterone (50 mg) at a growing (Day 3 after ovulation) or a static (Day 8) phase of the dominant follicle during the first follicular wave in CIDR-treated, lactating dairy cows. Previously synchronized, lactating dairy cows received CIDRs (InterAg, Hamilton, New Zealand; Day 0) 3 days after ovulation and were assigned to two treatment groups and a control group. Cows in the T1 group (n = 11) received 2 mg EB (SY Esrone; Samyang, Seoul, Korea) and 50 mg P4 (SY Ovaron; Samyang) i.m., and those in the control group (n = 10) received no treatment at that time. Other previously synchronized cows received a CIDR (Day 0) with injections of 2 mg EB plus 50 mg P4 i.m. 8 days after ovulation (T2 group, n = 10). Thereafter, all cows received PGF2� (Lutalyse; Pharmacia & Upjohn, Puurs, Belgium) at the time of CIDR removal on Day 7, and GnRH (Conceral; Dongbang Co., Seoul, Korea) on Day 9. Ovaries of each cow were examined by transrectal ultrasonography (Sonoace 600 with 7.5 MHz linear-array transducer; Medison Co., Ltd, Seoul, Korea) every 24 h from Days 0 to 9, on Day 11, and on Day 14 of treatment to observe changes in ovarian structures (follicles and corpora lutea (CL)). Data were analyzed by Fisher's exact test, Kruskal-Wallis test, and ANOVA using an SAS program (SAS Institute, Inc., Cary, NC, USA). Follicular wave emergence occurred within 7 days in 3/10 of the control group, 9/11 of the T1 group, and 9/10 of the T2 group (P < 0.05). The interval to wave emergence did not differ (P > 0.05) among groups (3.7 � 1.2, 4.8 � 0.5, 5.9 � 0.3 days, respectively). While the diameters of dominant follicles on Day 0 were greater (P < 0.01) in the T2 group (14.3 � 1.2 mm) than in the control (9.4 � 0.6 mm) and T1 (10.5 � 0.7 mm) group, diameters of preovulatory follicles on Day 9 were significantly smaller (P < 0.01) in the T1 (13.6 � 0.7 mm) and T2 (12.3 � 0.5 mm) groups than in the control group (16.4 � 0.8 mm). Synchronized ovulation by 40 h after the GnRH injection (Day 11) occurred in 10/10 of the control group, 10/11 of the T1 group, and 9/10 of the T2 group (P > 0.05). In conclusion, administration of 2 mg EB plus 50 mg P4 at both a growing and a static phase of the dominant follicle during the first follicular wave results in synchronous follicular wave emergence and development and also synchronized ovulation in CIDR-treated, lactating dairy cows.

19 EFFECTS OF ESTRADIOL OR GnRH ON FOLLICULAR WAVE EMERGENCE AND PREGNANCY RATES FOR A CIDR-BASED TIMED AI PROTOCOL IN REPEAT BREEDER DAIRY COWS

2007 ◽  
Vol 19 (1) ◽  
pp. 128
Author(s):  
G. H. Suh ◽  
U. H. Kim ◽  
T. Y. Hur ◽  
S. J. Kang ◽  
K. S. Baek ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Follicular Development ◽  
Economic Loss ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Corpora Lutea ◽  
Chi Square ◽  
Follicular Wave ◽  
Array Transducer ◽  
Repeat Breeder

Repeat breeding of a high yielding cow causes enormous economic loss to the dairy producers. In this study, we examined the effect of estradiol benzoate (EB) or GnRH on follicular wave emergence and follicular development, and on pregnancy rates for a CIDR-based timed AI (TAI) protocol in repeat breeder dairy cows. Repeat breeder cows received a CIDR device (InterAg, Hamilton, New Zealand), with an injection of 1 mg EB (SY Esrone�; Samyang, Seoul, Korea) plus 50 mg progesterone (P4; SY Ovaron�; Samyang) (EB + P4 group, n = 36) or with an injection of 250 �g Gonadorelin (GnRH, Fertagyl�; Intervet, Boxmeer, The Netherlands) (GnRH group, n = 35) at the beginning of the experiment (Day 0). On Day 7, CIDR devices were removed and all cows received PGF2� (Lutalyse�; Pharmacia &amp; Upjohn, Puurs, Belgium). Thereafter, cows in the EB + P4 group received an injection of 1 mg EB on Day 8, and TAI 30 h later; those in the GnRH group received an injection of 250 �g GnRH on Day 9, and TAI 19 h later. In a subset of cows for both groups (15 cows from each group), the ovaries of the cows were examined by transrectal ultrasonography (Sonoace 600 with 7.5 MHz linear-array transducer; Medison Co., Seoul, Korea) every 24 h from Days 0 to 8, on Day 10, and on Day 13 for the EB + P4 group, and every 24 h from Days 0 to 9, on Day 11, and on Day 14 for the GnRH group, to observe changes in ovarian structures (follicles and corpora lutea). Pregnancy was diagnosed 35 to 60 days after TAI, using both ultrasonography and rectal palpation. Data were analyzed using Fisher&apos;s exact, Student&apos;s t-, and chi-square tests. Follicular wave emergence occurred within 7 days in 12/15 EB + P4-treated and 13/15 GnRH-treated cows (P &gt; 0.05). The mean diameters of preovulatory follicles were smaller (P &lt; 0.05) in the EB + P4 group (12.1 � 0.1 mm) than in the GnRH group (13.8 � 0.1 mm). However, the proportion of cows with synchronized ovulation and pregnancy rates to TAI did not differ (P &gt; 0.05) between the EB + P4 (11/15 and 19.4%, respectively) and the GnRH (13/15 and 34.3%, respectively) groups. In conclusion, treatment with either EB or GnRH for a CIDR-based TAI protocol in repeat breeder dairy cows results in synchronous follicular wave emergence, follicular development, and ovulation, and thus similar pregnancy rates to TAI.

Effect of 1 or 2 norgestomet implants inserted from days 15 to 25 after oestrus on follicular development in beef cows

1996 ◽  
Vol 1996 ◽  
pp. 133-133
Author(s):  
D.A. Adikpe ◽  
M.J. Bryant
Keyword(s):  
Pregnancy Rate ◽  
False Positive ◽  
Luteal Phase ◽  
Follicular Development ◽  
Beef Cows ◽  
Beef Heifers ◽  
Follicular Wave ◽  
Ovulatory Follicle

Controlling the timing of ovulation in cows that fail to conceive after insemination would provide a further opportunity for scheduled rebreeding in a group of cows to save time and optimise results. The ear implant Crestar containing the synthetic progestagen norgestomet provides a means of achieving this control (Sinclair et al., 1992; Lowman et al., 1994). Removing the implant on day 25 after oestrus results in less false positive pregnancy diagnoses than removal on day 21 with the implant in place for nine/ten days. However, treatment of beef heifers with a norgestomet implant towards the end of luteal phase to control oestrus and ovulation is associated with development of a persistent ovulatory follicle and reduced pregnancy rate (Mihm et al., 1994). The objective of this study was to determine the effects of treating beef cows with one or two norgestomet implants on the development of the dominant ovulatory follicle of the second follicular wave.

36 FOLLICULAR DYNAMICS IN PROLIFIC SHEEP: PGF-BASED ESTRUS SYNCHRONIZATION

2010 ◽  
Vol 22 (1) ◽  
pp. 176
Author(s):  
L. Proctor ◽  
D. Tutt ◽  
D. Olliver ◽  
S. Galloway ◽  
J. L. Juengel ◽  
...  
Keyword(s):  
Animal Health ◽  
T Test ◽  
Corpora Lutea ◽  
Follicular Wave ◽  
Follicle Diameter ◽  
Array Transducer ◽  
Significant Difference ◽  
Preovulatory Follicles ◽  
Student’S T ◽  
Follicular Dynamics

A study was designed to compare the effect of a prostaglandin-based synchronization protocol on ovarian follicular dynamics in sheep with the FecB (Booroola) mutation. Forty dry Romney sheep (57.6 ± 7.3 kg; 6.1 ± 1.1 years) were randomly selected from both Invermay Booroola (BB; n = 20) and commercial (non-FecB carriers, ++; n = 20) flocks. All ewes had their estrous cycles synchronized with 2 i.m. injections of PGF (150 μg of cloprostenol, Estrumate, Schering-Plough Coopers Animal Health Ltd., New Zealand) administered 7 days apart. Ewes were monitored by transrectal ultrasonography (Aloka 900-SSD and a 7.5-MHz linear-array transducer, Aloka, Tokyo, Japan) daily from Day -2 to the day of ovulation. Data were analyzed by Student’s t-test or Wilcoxon Rank Sum test. Variances were compared with Barlett’s test. Paired t-test compared the number of preovulatory follicles in each genotype after PGF treatments and intervals from PGF to ovulation after PGF. Data are presented as mean (± SEM). The number of corpora lutea (CL) and total CL area at the time of the first and second PGF treatment were 4.4 ± 0.6; 5.7 ± 1.4 and 672.1 ± 133.5 mm2; 999.0 ± 145.9 mm2 in the BB and 2.1 ± 0.2; 2.1 ± 0.5 and 342.3 ± 60.7 mm2; 401.3 ± 68.6 mm2 in ++ ewes, respectively. These 2 variables were higher (P < 0.01) at both PGF injections in the BB than in the ++ ewes, except the CL area at the time of first PGF treatment (P = 0.15). The largest follicle diameter at the time of the first and second PGF treatments was smaller (P < 0.003) in BB (4.1 ± 0.3 mm; 3.5 ± 0.2 mm) than in ++ (5.3 ± 0.3 mm; 5.8 ± 0.1 mm) ewes. The median and mean number of follicles that ovulated after the first and second PGF treatment were higher (P < 0.0001) in BB (6 & 7; 5.7 ± 0.3; 6.9 ± 0.3; difference = 1.2 ± 0.4; P < 0.003) than in the ++ (2 & 2; 2.1 ± 0.1; 2.1 ± 0.1) sheep. The luteal area at the time of first and second PGF in both BB and ++ did not differ (P = 0.3). The intervals from the first and second PGF to the respective ovulations did not differ (P > 0.61) between BB (3.4 ± 0.2; 3.0 ± 0.3d) and ++ (3.5 ± 0.2d; 3.0 ± 0.1d) ewes. However, interval from the second PGF to ovulation was more variable (P = 0.002) in the BB than in the ++ ewes. Data of both groups were combined and a mean significant difference of 0.6 ± 0.2d (P < 0.003) was found between the first and second PGF-to-ovulation intervals. The interval from the first PGF to emergence of the next follicular wave was shorter (P < 0.02) and more variable (P < 0.03) in the BB (2.7 ± 0.4d) than in the ++ (3.5 ± 0.2 d) group. Preovulatory follicles were smaller in Booroola, but higher in number, than in ++ ewes, whereas the luteal area was similar. Within the BB ewes, the higher number of follicles that ovulated after the second PGF than after the first injection may be due to a higher follicular response to an elevated rebound in circulating FSH after the first PGF. A high number of growing follicles of the first follicular wave may also have contributed to this event. These findings warrant further research aimed at the study of the interaction between FSH and follicle dynamics in estrus synchronized sheep carrying the FecB mutation.

156 THE USE OF THE DG29™ ENZYME-LINKED IMMUNOSORBENT ASSAY KIT TO PREDICT PREGNANCY PRIOR TO EMBRYO TRANSFER IN LACTATING HOLSTEIN COWS

2013 ◽  
Vol 25 (1) ◽  
pp. 226
Author(s):  
Y. Nakamura ◽  
A. Ideta ◽  
A. Shirasawa ◽  
K. Hayama ◽  
S. Sakai ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Statistical Significance ◽  
Visual Observation ◽  
Holstein Cows ◽  
Enzyme Linked Immunosorbent Assay ◽  
Animal Reproduction ◽  
Array Transducer ◽  
Significant Difference ◽  
Chi Squared ◽  
Student’S T

Evaluation of postpartum fertility in cows is important for the efficient management of reproduction. DG29™ enzyme-linked immunosorbent assay (ELISA) kit (Conception, Animal Reproduction Technologies, Canada) measures the level of pregnancy–related glycoproteins in blood that are linked to pregnancy in the bovine species. The proteins are known to persist in the postpartum period. Here, we investigated whether the postpartum fertility in Holstein dairy cows can be evaluated through the use of the DG29 kit. We confirmed that genital organs of lactating Holstein cows (n = 119, from Days 56 to 688 postpartum) were normal by a 5.0/7.5-MHz linear array transducer (Tringa, Pie Medical Equipment B.V., Maastricht, The Netherlands), then a progesterone releasing intravaginal device (PRID; CEVA Sante Animale, Libourne, France) was inserted (Day 0) and maintained for 9 days. On Day 7, PGF2α was administered (2 mL Dalmazine, Kyoritsu Seiyaku, Tokyo, Japan). Blood samples were collected from the tail vein or artery into vacuum tubes at the time of PRID insertion. Serum was separated and stored at –30°C until the ELISA was performed. Oestrus (Day 0) was detected by visual observation. Fresh embryos recovered from Japanese Black cows were transferred to 119 recipient cows in various parities (primiparous = 70, biparous = 27, and multiparous = 22) on Days 6 to 8 of oestrous cycle. Pregnancy was diagnosed between Days 40 to 60 by transrectal ultrasonography. The statistical significance of any differences between various parities was assessed by chi-squared and Student’s t-tests. The pregnancy rate was higher for primiparous cows than for biparous and multiparous cows (64.3, 55.6, and 54.5%, respectively), while concentrations of the pregnancy-related glycoproteins in primiparous cows (135.0 ± 29.8 pg mL–1) were significantly lower than those of biparous (389.4 ± 175.9 pg mL–1) and multiparous cows (399.2 ± 203.1 pg mL–1, mean ± SEM; P < 0.05). In primiparous and multiparous cows, the concentrations of pregnancy-related glycoproteins were significantly lower in pregnant cows compared with nonpregnant cows (primiparous: 81.1 ± 29.9 v. 232.6 ± 59.8 pg mL–1; P < 0.05; multiparous: 20.8 ± 16.2 v. 853.4 ± 411.5 pg mL–1; P < 0.05). However, there was no significant difference between pregnant and nonpregnant biparous cows. In conclusion, the DG29 kit may be useful for the prediction of postpartum fertility in lactating Holstein cows. Further studies are needed to test the validity of this observation by using a greater number of various parties’ cows.

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

2021 ◽  
Vol 33 (2) ◽  
pp. 165
Author(s):  
V. L. Brair ◽  
A. B. P. Andrade ◽  
M. C. C. Morais ◽  
P. S. C. Rangel ◽  
M. E. F. Oliveira ◽  
...  
Keyword(s):  
Chorionic Gonadotrophin ◽  
Dairy Goats ◽  
Short Term ◽  
Exact Test ◽  
Ovulatory Follicle ◽  
Chi Squared ◽  
Student’S T ◽  
Equine Welfare ◽  
Levene Test ◽  
Student’S T Test

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&lt;0.05 were considered significant. According to the breed and parity order, Nubian and Saanen goats showed no difference (P&gt;0.05) in reproductive parameters. Alpine goats had a longer (P&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&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&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&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&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&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).

Serum oestradiol and preovulatory follicular development before in-vitro fertilization

1984 ◽  
Vol 101 (1) ◽  
pp. 113-118 ◽  
Author(s):  
S. G. Hillier ◽  
J. H. Parsons ◽  
R. A. Margara ◽  
R. M. L. Winston ◽  
M. E. Crofton
Keyword(s):  
In Vitro Fertilization ◽  
Follicular Development ◽  
Fluid Volume ◽  
Vitro Fertilization ◽  
Ovulatory Follicle ◽  
Significant Linear Correlation ◽  
Normal Term ◽  
Embryo Replacement ◽  
Ovulatory Follicles

ABSTRACT Twenty-three in-vitro fertilization (IVF) treatment cycles (four unstimulated and 19 clomiphene-stimulated) were assessed retrospectively to discern relationships among serum oestradiol (OE2) titre on the day that human chorionic gonadotrophin (hCG) was given and the number and size of ovulatory follicles available for aspiration of oocytes during laparoscopy 32–38 h after hCG injection. Since 12 of the cycles succeeded to the stage of embryo replacement and two normal term pregnancies resulted, the series as a whole offers a useful referent data base. When only one ovulatory follicle developed (n = 8) the average volume of aspirated follicular fluid was approximately 6 ml, equivalent to a follicular diameter between 22 and 23 mm. When multiple follicles developed (mean 2·7/patient, n = 15), average fluid volume/follicle was not significantly different, averaging approximately 5·5 ml. Serum OE2 titre on the morning before hCG was injected ranged between 0·9 and 5·5 nmol/l and corresponded to the number of follicles aspirated at laparoscopy. There was a highly significant linear correlation (r = 0·85, P <0·001) between this OE2 value (X nmol/l) and total aspirated fluid volume (Y ml) where Y = 2·07 + 3·65 X. Thus taking 6 ml as the 'typical' fluid volume, the calibration line and its 95% confidence limits could be used to establish provisional 'ideal' pre-hCG serum OE2 titre ranges corresponding to the development of one, two or three mature ovulatory follicles. This information, combined with a knowledge of the number of presumptive preovulatory follicles present (assessed by ovarian ultrasound), can aid the timing of the hCG injection before IVF. J. Endocr. (1984) 101, 113–118

224 OVARIAN FOLLICLE DEVELOPMENT DURING SEASONAL TRANSITION IN WAPITI

2006 ◽  
Vol 18 (2) ◽  
pp. 220
Author(s):  
R. McCorkell ◽  
M. Woodbury ◽  
G. Adams
Keyword(s):  
Breeding Season ◽  
Ovarian Follicle ◽  
Follicular Development ◽  
Maximum Diameter ◽  
Follicle Development ◽  
Estrous Cycles ◽  
Ovarian Follicle Development ◽  
Array Transducer ◽  
October 17 ◽  
Ovulatory Follicles

Wapiti are seasonally polyestrous. The transition into and out of the breeding season is marked by resumption of ovulation in autumn and cessation of ovulation in winter. Onset of ovulatory cyclicity is distinct and associated with aggressive breeding behavior of stags in rut. Cessation of ovulation at the end of the breeding season is not distinguished by behavioral patterns. The objective of the present study was to characterize follicular and luteal dynamics in wapiti during the transitional periods into and out of the breeding seasons. Transition from anestrus to estrus was monitored in 15 hinds, aged 2 to 14 years, over two successive seasons (11 in year 1, with 5 hinds from year 1 used again in year 2 along with 4 new hinds; n = 20 observations). Transition from estrus to anestrus was monitored in 11 hinds over 1 season (n = 11 observations). Hinds were maintained on a farm near Saskatoon, Saskatchewan (52°07′N, 106°38′W). The ovaries were examined daily during September through October by transrectral ultrasonography using a B-mode ultrasound machine and a 7.5 MHz linear array transducer for transition to estrus, and December through April for transition to anestrus. The first ovulation was recorded on September 15 and all hinds had ovulated for the first time by October 7. In 17 of 20 observations, the duration of the first interovulatory interval (IOI) was 9.3 ± 0.4 days (mean ± SEM). With one exception, these IOIs were characterized by one wave of follicular development. The remaining three IOIs ranged from 16 to 23 days and consisted of two or three waves of follicle development. The second ovulation occurred by October 15 in hinds with a short IOI and by October 17 in all remaining hinds. The mean dates of first and last ovulation were September 25 and February 7, respectively, an interval of 135 days. The median date of the last ovulation was February 15 and the range was from December 3 to March 22. Duration of the last IOI of the season (21.2 ± 0.6 days) was similar to the notional 21-day cycle for wapiti, but longer (P < 0.05) than the duration of the first IOI (10.9 ± 1.0 days). Maximum diameters of the first 2 ovulatory follicles were similar (11.3 ± 0.4 vs. 11.3 ± 0.2 mm), but were larger (P < 0.05) than the last 2 ovulatory follicles of the breeding season (10.3 ± 0.3 vs. 10.1 ± 0.4 mm). Maximum diameter of the corpus luteum (CL) tended (P = 0.06) to be smaller for the short IOI than for longer IOI of the first and last cycles. Diameter of the last CL of the season was not different from that of the previous CL (12.8 ± 0.6 vs. 12.5 ± 0.6 mm); however, it was detected for a longer period (22.3 ± 1.2 vs. 19.3 ± 0.7 days; P < 0.05). Estrous cycles during transition into the breeding season have been described as being irregular and those out of the breeding season as increasingly long. In the present study, the transition periods were characterized by regular events. Transition to regular estrous cycles was preceded by one short (9 days) IOI. The last IOI of the breeding season was the same as that reported during the rut. Transition to anestrus occurred most commonly in February and was marked by a failure of the dominant follicle to ovulate after luteal regression.

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