Regulation of Ovulation Rate

1996 ◽  
pp. 1-20 ◽  
Author(s):  
Jimmy L. Spearow
Keyword(s):  
Author(s):  
J.M. Hayman ◽  
J.M. Munro
Keyword(s):  

Keyword: wilted silage, flushing, ovulation rate


2017 ◽  
Vol 95 (7) ◽  
pp. 3160
Author(s):  
C. L. A. Da Silva ◽  
M. L. W. J. Broekhuijse ◽  
B. F. A. Laurenssen ◽  
H. A. Mulder ◽  
E.F. Knol ◽  
...  
Keyword(s):  

2014 ◽  
pp. 86-93
Author(s):  
Minh Tam Le

Backgrounds: Polycystic Ovary Syndrome (PCOS) is one of the most common causes of female infertility due to ovulation disorders. Clomiphene citrate (CC) is a first choice to restore ovulation but it has some side effects by estrogen receptor down-regulation. Aromatase inhibitor (AI) is a newer class of drugs which increases the production of endogenous FSH to stimulate ovulation. Subjects and methods: randomized control trial to compare 64 cases of infertile women with PCOS examined at the Hue University Hospital, alternately used AI (group I) or CC (group II) for ovulation induction from day 2 cycle. Follow-up follicle growth, endometrium and ovulation via ultrasound. Evaluation were done on 10th day cycle, day of hCG trigger and after administration of hCG. Results: Total of 64 PCOS cases distributed into 2 groups using alternatively AI and CC had similar characteristics with average age of 28.8 ± 4.6, the majority were primary infertility (84.4%), infertility duration was 2.6 ± 2.4 years, 85.9% had oligomenorrhrea or amenorrhea, normal body mass index accounts for 60.9% and 21.9% was lean. Evaluation of both groups on day 10 revealed no differences in the dominant follicle and endometrial thickness. Number of days until the follicle mature appears to be shorter in AI group (15.1 ± 2.9) compared to the CC group (16.5 ± 2.8) with statistical significance. The number of mature follicles in 2 groups were not different at a rate of 81.3% (AI) and 84.4% (CC) but a higher proportion of single mature follicle in the AI ​​group (71.9%) compared with the CC group (65.7%) and There is no case with 3-4 mature follicles in the AI group. The rate of thin endometrium (<8 mm) in the AI group (25%) was lower than the CC group (53.1%) with statistically significance and higher ovulation rate (68.8%) compared with the CC group (56.3%) but have not found statistically significant. Conclusion: Two drugs AI and CC potentially induce follicle development and ovulation similarly, but AI has the potential to be more effective than CC on factors such as the shorter stimulation duration, increasing rate of single follicle, limiting multiple pregnancies, improve endometrial thickness and higher ovulation rate. More researches are needed with a larger sample size to clarify the statistical significance of differences.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 112-113
Author(s):  
Marcelo Siqueira El Azzi ◽  
Everardo Anta Galvan ◽  
Teresita Valdes Arciniega ◽  
Iago Leão ◽  
Rodrigo Sala ◽  
...  
Keyword(s):  

Abstract The objective was to determine the effect of hCG (3,300 IU) administered on days 0 and/or 5 of the estrous cycle on total luteal area (TLA) and circulating concentrations of progesterone (P4) in recipient heifers. All heifers (n = 232; BCS = 3.3 ± 0.2) were synchronized with a 5d CIDR-Synch protocol (d-8: used CIDR inserted; d-3: CIDR removed and PGF2α treatment; d0: 100µg GnRH or hCG). Heifers were randomly assigned to four treatments: control, hCGd0, hCGd5, and hCGd0&5. Controls were treated with GnRH on d0, while hCGd0 received hCG on d0. hCGd5 heifers were treated with GnRH on d0 and hCG on d5, while hCGd0&5 received hCG on d0 and 5. Ovaries were scanned by ultrasound on d0, 5, and 12. Blood was collected on d0, 5, 7, and 12. Synchronization rate (94%) did not differ (P = 0.94) by treatment. Treatment differences were only tested in synchronized heifers (n = 218). Proportion of heifers with 1 or 2+ CL on d5 did not differ (P = 0.10) for hCG d0 treatments (hCGd0 + hCGd0&5) vs. GnRH d0 treatments (controls + hCGd5). However, heifers treated with hCG on d0 had greater (P &lt; 0.01) TLA and P4 on d5 vs. treatments with GnRH on d0 (311 ± 13 vs. 257 ± 9 mm2; and 2.39 ± 0.15 vs. 1.90 ± 0.09 ng/mL). Ovulation rate for d5 hCG did not differ (P = 0.63) for hCGd5 vs. hCGd0&5 (93 vs. 84%). Controls had the lowest serum P4 on d7 and 12. In contrast, hCGd0&5 had the highest serum P4 on d7 (Table 1). Serum P4 on d7 did not differ for hCGd0 vs. hCGd5. On d12, serum P4 and TLA were not different for hCGd5 vs. hCGd0&5. These data indicate that hCG can be used on d0 to induce an increase in serum P4 on d5 compared to GnRH. However, only heifers treated with hCG on d5 achieved mean serum P4 &gt; 8ng/mL.


1991 ◽  
Vol 53 (3) ◽  
pp. 407-409 ◽  
Author(s):  
F. Forcada ◽  
J. A. Abecia ◽  
L. Zarazaga

The attainment of puberty in September-born early-maturing ewe lambs was studied at Zaragoza (latitude 41° 40' N). Thirty twin Salz females were allocated to two groups receiving two nutrition levels after 3 months of age: high (500 g/day lucerne hay and 500 g/day concentrate) (H) and low (500 g/ day lucerne hay) (L). Oestrus was detected daily by aproned rams. Corpora lutea were counted after oestrus and plasma progesterone levels monitored each week.In the first breeding season (January to February) the percentage of females showing sexual activity (silent emulation or oestrus and ovulation) was higher in the H compared with the L group (67 and 20%; P < 0/05). Nonpubertal oestrus before the main breeding season was detected in 67% of animals. In the main breeding season and for H and L groups respectively, percentage of females showing silent ovulation before puberty was 67 and 33% and mean age at puberty extended to 319 (s.e. 4-8) and 314 (s.e. 3·7) days. Ovulation rate at puberty was 1·73 (s.e. 0·13) and 1·33 (s.e. 0·15) respectively (P < 0·05).


2002 ◽  
Vol 87 (7) ◽  
pp. 3391-3393 ◽  
Author(s):  
Lourdes Ibáñez ◽  
Neus Potau ◽  
Angela Ferrer ◽  
Francisco Rodriguez-Hierro ◽  
Maria Victoria Marcos ◽  
...  

1979 ◽  
Vol 29 (2) ◽  
pp. 277-282 ◽  
Author(s):  
R. G. Gunn ◽  
J. M. Doney ◽  
W. F. Smith

ABSTRACTOver 2 years, 104 Greyface ewes were mated at a synchronized oestrus either in early October or early November. From late September until slaughter at return to service or between 4 and 7 weeks after mating, ewes were fed to maintain their body condition score as previously adjusted by differential group feeding on grass. Ovulation rate and potential lambing rate were derived from counts of corpora lutea and viable embryos at slaughter. Both rates were higher in the early-mated ewes in comparable body condition. Stress factors were implicated as contributing to the decline in ovulation rate with time, while ewes which failed to hold to first mating were largely responsible for the decline in potential lambing rate.


1979 ◽  
Vol 29 (1) ◽  
pp. 17-23 ◽  
Author(s):  
R. G. Gunn ◽  
J. M. Doney ◽  
W. F. Smith

ABSTRACTIn two experiments over 2 years, 57 North Country Cheviot and 82 South Country Cheviot hill ewes were differentially group-fed indoors over a 2-month period to achieve either good or moderate body con- dition. Over 5 weeks prior to mating, ewes in good condition were brought down in condition by restricted feeding and ewes in mod- erate condition were raised in condition by a high level of feeding. The ewes were thus in moderately-good condition at mating. After mating, ewes were maintained in this condition until killed either on return to service or at 29 ± 8 days for counts of corpora lutea and viable embryos.Ovulation rate in each breed was positively related to the level of pre-mating food intake at the condition level studied. Embryo mortality, as ova loss, was not influenced overall by the level of pre-mating food intake but loss of multiple-shed ova was greater than that of single-shed ova in ewes which had been on restricted feeding before mating. Although a greater proportion of ewes in the North Country Cheviot breed were not pregnant at slaughter, this could not be identified as a breed difference since the breeds were studied in different years.


Reproduction ◽  
2010 ◽  
Vol 140 (6) ◽  
pp. 865-874 ◽  
Author(s):  
C Viñoles ◽  
B Paganoni ◽  
K M M Glover ◽  
J T B Milton ◽  
D Blache ◽  
...  

We have developed an experimental model in which groups of ewes are simultaneously experiencing the first ovarian follicular wave of their oestrous cycle. We used this ‘first-wave model’ in a 2×2 factorial experiment (ten ewes per group) to study the effect of body condition (BC) and a short-term supplement on follicular dynamics and ovulation rate. The ‘first-wave’ was established by giving ewes three injections of prostaglandin (PG), 7 days apart. The 6-day supplement (lupin grain) began 2 days after the second PG injection and continued until the third. Follicles were studied by ultrasound, and blood was sampled to measure glucose and hormones. The supplement increased (P<0.01) the concentrations of glucose, insulin and leptin, decreased FSH concentrations (P<0.01) and tended to increase oestradiol concentrations (P=0.06). The supplement tended to increase the number of 3 mm follicles (P=0.06). Compared with low-BC ewes, high-BC ewes had more follicular waves (P<0.05), higher concentrations of insulin, leptin and IGF1 (P<0.05) and tended to have higher FSH concentrations (P=0.09). Leptin and insulin concentrations remained high until the end of supplementation in high-BC ewes, whereas they decreased after the third day of supplementation in low-BC ewes. In conclusion, high concentrations of metabolic hormones in fat ewes are associated with the development of more follicular waves. When a supplement is superimposed on this situation, changes in glucose and metabolic hormones allow more follicles to be selected to ovulate.


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