The effect of stage of breeding season or pre-mating oestrogen and progestagen therapy on fertility in ewe lambs

1994 ◽  
Vol 59 (3) ◽  
pp. 429-434 ◽  
Author(s):  
N. F. G. Beck ◽  
M. C. G. Davies
Keyword(s):  
Breeding Season ◽  
Corpora Lutea ◽  
Oestrogen Therapy ◽  
Crown Rump Length ◽  
Ewe Lambs ◽  
Oestradiol Benzoate

AbstractAn investigation was conducted to determine the effect of mating at puberty or third oestrus or after pre-mating oestrogen and progestagen therapy, designed to mimic the changes that occur in plasma oestrogen and progesterone concentrations during the 1st, 2nd or 3rd oestrous cycles, on fertility in ewe lambs. Twenty-five ewe lambs were mated at puberty on mean date of 18 October and 21 were mated at third oestrus on 3 December. Of these, 28% and 81% of animals mated at puberty and third oestrus lambed, respectively (P < 0·05). A similar number of ewe lambs were mated within 24 h of ram introduction in the groups given one, two or three consecutive applications oestrogen and progestagen (25 μg oestradiol benzoate followed 48 h later by a progestagen pessary left in situ for days). Of the 43 corpora lutea, 21 were represented by viable embryos in the 37 animals holding to service after one application compared with 34 out of 46 corpora lutea in 40 animals given three applications (P < 0·05). Furthermore, embryo crown-rump length, embryo weight and amniotic sac width was greater (P < 0·05), on day of pregnancy, in animals given one compared with three applications of oestrogen and progestagen. These results demonstrate that fertility is improved in ewe lambs mated on third oestrus or after progestagen and oestrogen therapy designed to simulate three oestrous cycles.

A note on attainment of puberty of september-born early-maturing ewe lambs in relation to level of nutrition

1991 ◽  
Vol 53 (3) ◽  
pp. 407-409 ◽  
Author(s):  
F. Forcada ◽  
J. A. Abecia ◽  
L. Zarazaga
Keyword(s):  
Sexual Activity ◽  
Breeding Season ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Ewe Lambs ◽  
Early Maturing ◽  
Age At Puberty

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).

HORMONAL CONTROL OF AMNIOTIC AND ALLANTOIC FLUID VOLUME IN OVARIECTOMIZED SHEEP

1968 ◽  
Vol 41 (4) ◽  
pp. 477-485 ◽  
Author(s):  
G. ALEXANDER ◽  
D. WILLIAMS
Keyword(s):  
Ovarian Tissue ◽  
Allantoic Fluid ◽  
Hormonal Control ◽  
Fluid Volume ◽  
Corpora Lutea ◽  
Dose Ratio ◽  
Oestradiol Benzoate ◽  
Bovine Type ◽  
Excessive Accumulation

SUMMARY In pregnant ewes, ovariectomized 3 weeks after mating and maintained with progesterone (7 mg./day) injected intramuscularly, there was excessive accumulation of allantoic fluid after 2 months of gestation. The addition of oestradiol benzoate (5 μg./day) or an increase in the dose of progesterone reduced the allantoic fluid volume to normal; this reduction depended on the dose of oestrogen and on the dose ratio of oestrogen to progesterone. Whilst oestrogen reduced allantoic fluid volume to normal, it increased the incidence of 'bovine' type of cotyledons which are not normally seen in ewes 2 months pregnant. The large allantoic volumes were apparently due to the absence of luteal rather than other ovarian tissue, since large volumes were also present in ewes maintained on 7 mg. progesterone/day after corpora lutea had been surgically expressed from the ovaries left in situ. Embryonic survival was adversely affected when corpora lutea were removed from the ovaries, but there was no clear effect on the morphology of cotyledons.

Comparison of luteal function between ewe lambs and ewes during breeding and non breeding season

1998 ◽  
Vol 1998 ◽  
pp. 184-184
Author(s):  
T.H. Khan ◽  
N.F.G. Beck ◽  
M. Khalid
Keyword(s):  
Embryo Development ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Corpora Lutea ◽  
Luteal Function ◽  
Previous Evidence ◽  
Ewe Lambs

Reproductive performance of ewe lambs is lower than that of adult ewes (Quirke. 1979). This is mainly the result of preimplantation losses which can exceed 50% in ewe lambs as compared with 20-30% in ewes (Quirke et al.,1981). Previous evidence from this laboratory suggests that these losses may be associated with inadequate luteal function in ewe lambs (Davies and Beck, 1993). Inadequate luteal function may not only delay the embryo development but also impair the ability of the embryo to communicate its presence to the maternal system. There is also a possibility that inadequate corpora lutea may be refractory to luteotrophic factors produced by the developing embryo. The present study was designed to investigate whether the luteal function varies between ewe lambs and ewes. Another objective of this study was to compare the luteal response to hCG challenge between ewe lambs and ewes and its variation with season.

The effect of long photoperiod or bromocryptine treatment on prolactin concentration and fertility in ewe lambs mated at induced oestrus

1995 ◽  
Vol 60 (2) ◽  
pp. 209-214
Author(s):  
N. F. G. Beck ◽  
M. C. G. Davies ◽  
B. Davies
Keyword(s):  
Control Group ◽  
Corpora Lutea ◽  
Plasma Prolactin ◽  
Progesterone Concentration ◽  
Embryo Survival ◽  
Crown Rump Length ◽  
Growth And Survival ◽  
Ewe Lambs ◽  
Group B ◽  
Long Photoperiod

AbstractAn investigation was conducted into the effects of increasing plasma prolactin concentration with long photoperiod or suppressing it with bromocryptine on the fertility of ewe lambs. One hundred and twenty dim Forest ewe lambs were divided into three groups: group C was kept as a control; group L was exposed to a long photoperiod (16 h light: 8 h dark) and group B was given daily injections of 1 mg bromocryptine from 12 days before until 21 days after mating. All three groups were mated in late November, 30 days after housing, following progestagen/PMSG treatment. Post-mating prolactin concentrations were significantly higher in group L and lower in group B compared with group C (P > 0·05). There was a tendency for pregnancy rate and the number of corpora lutea to be represented by viable foetuses to be lower in group L than in group C (P < 0·05). Furthermore, post-mating progesterone concentration was higher in this group compared with those in group C (P > 0·05). In a second experiment, 100 Welsh Χ Texel ewe lambs were given treatment C or L. Embryo survival tended to be lower and crown rump length, embryo weight and amniotic sac width were reduced at 25 days post mating in the animals given treatment L, compared with those given treatment C (P < 0·05). The combined results of the experiments indicated that fewer corpora lutea were represented by viable embryos or foetuses in group L than in group C (P < 0·05). These results suggest that embryo growth and survival is reduced in animals bred under a long photoperiod.

107 EARLY EMBRYONIC SURVIVAL IN THE PIG IS HIGHER THAN CONVENTIONALLY REPORTED

2009 ◽  
Vol 21 (1) ◽  
pp. 153 ◽  
Author(s):  
E. Østrup ◽  
M. Vejlsted ◽  
M. B. Nielsen ◽  
M. T. Madsen ◽  
P. Maddox-Hyttel
Keyword(s):  
Recovery Rate ◽  
Primitive Streak ◽  
Embryonic Mortality ◽  
Corpora Lutea ◽  
Gestational Length ◽  
Crown Rump Length ◽  
Embryo Recovery ◽  
Somite Stage ◽  
Group 2

It is generally accepted that 30% of the embryos in a porcine litter die within the first 40 days of pregnancy (Pope WP and First NL 1985 Theriogenology 23, 91–105). The aim of the study was to investigate the dynamics of embryonic mortality from the 2nd to the 7th week of pregnancy in a homogeneous pig population in order to test whether this dogma holds true. A total of 141 pregnant Danish Landrace × Yorkshire gilts were divided into three groups dependent on gestational length: Group 1 (Days 9 to 24 post insemination (p.i.)): At Days 9 to 18 p.i., embryos were collected by flushing the uterine horns with PBS containing 1% serum. At Days 19 to 24, embryos were identified in situ by opening of the horns along the anti-mesometrial side. All embryos were staged according to the morphological appearance of embryo proper. Pre-somite stage embryos were categorized as either: Hatched blastocysts, pre-streak 1, pre-streak 2, primitive streak, or neural groove stage embryos (Vejlsted M et al. 2006 Mol. Reprod. Dev. 73, 709–718). Somite stage embryos were staged according to the number of somites. All embryos in Group 2 (Days 24.5 to 33 p.i.) and Group 3 (Days 40.5 to 47 p.i.) were identified in situ by opening the uterine horns as described above. The localization in the uterus and the Crown Rump Length (CRL) was recorded for all embryos in these groups. The average embryo recovery rate, (i.e. the ratio between the numbers of recovered embryos and the CL numbers) was 82%. Moreover, there were no significant differences between the groups with respect to the embryo recovery rate, signaling the absence of continued embryonic mortality. No significant correlations were obtained between the location of the embryos in the uterus and the CRL (only measured for Groups 2 and 3). Our data indicate that (1) the level of embryonic mortality was less than 10 to 15% and (2) there was no continued embryonic mortality occurring between Days 9 to 47 p.i. This is in great contrast to previous reports. Furthermore, there is no evidence that the location in the uterine horn has any influence on the embryonic development. Table 1.The average numbers of corpora lutea (CL), embryos, and the embryo recovery rates in gilts at different time points after insemination The Danish Research Council for Technology and Production Sciences.

Comparison of luteal function between ewe lambs and ewes during breeding and non breeding season

1998 ◽  
Vol 1998 ◽  
pp. 184-184
Author(s):  
T.H. Khan ◽  
N.F.G. Beck ◽  
M. Khalid
Keyword(s):  
Embryo Development ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Corpora Lutea ◽  
Luteal Function ◽  
Previous Evidence ◽  
Ewe Lambs

Reproductive performance of ewe lambs is lower than that of adult ewes (Quirke. 1979). This is mainly the result of preimplantation losses which can exceed 50% in ewe lambs as compared with 20-30% in ewes (Quirke et al.,1981). Previous evidence from this laboratory suggests that these losses may be associated with inadequate luteal function in ewe lambs (Davies and Beck, 1993). Inadequate luteal function may not only delay the embryo development but also impair the ability of the embryo to communicate its presence to the maternal system. There is also a possibility that inadequate corpora lutea may be refractory to luteotrophic factors produced by the developing embryo. The present study was designed to investigate whether the luteal function varies between ewe lambs and ewes. Another objective of this study was to compare the luteal response to hCG challenge between ewe lambs and ewes and its variation with season.

PSVII-3 Evaluation of dietary OmniGen AF supplementation and PG600 injection on reproductive characteristics of gilts

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 411-411
Author(s):  
Jun Chen ◽  
Jung Wook Lee ◽  
Jim J Monegue ◽  
Richard Niblett ◽  
Kim Williams ◽  
...  
Keyword(s):  
Animal Health ◽  
Basal Diet ◽  
Corpora Lutea ◽  
Crown Rump Length ◽  
Reproductive Characteristics ◽  
Ovary Weight ◽  
Diet Formulation ◽  
Two Factors ◽  
Diet Control ◽  
Dietary Treatments

Abstract A cooperative study evaluated effects of supplemental dietary OmniGen AF (OG; Phibro Animal Health Corporation) on reproductive characteristics of gilts. Crossbred gilts (n = 56; initial body weight = 152.3 ± 9.7 kg) were assigned to treatments in a 2 x 2 factorial design [diet (OG or control) and PG600 (Merck Animal Health, El Dora, KS) injection (Yes or No)]. Dietary treatments were: 1) corn-SBM basal diet (control) that met NRC (2012) requirement estimates, or 2) control plus 0.75% OG and were fed 35 to 40 d prior to breeding. A common diet formulation was used by both stations. Gilts were estrous-synchronized by 14-d feeding of Matrix (Merck Animal Health). PG600 injections occurred 24 hours after Matrix withdrawal. Gilts were weighed at breeding and preslaughter (at d 39 to 48 postbreeding) and were euthanized to evaluate reproductive characteristics. There were no OG x PG600 interactions on any response measures (P &gt; 0.15). Mean responses did not differ (P &gt; 0.20) when gilts were fed control or OG diets, respectively, for total uterus weight (6,065 vs. 5,883 g), uterine horn length (129.2 vs. 123.9 cm), ovary weight (9.66 vs. 9.94 g), total corpora lutea (CL) number (25.0 vs. 25.3), individual CL weight (0.41 vs. 0.43 g), total follicular fluid weight (3.17 vs. 3.03 g), individual placenta weight (86.3 vs. 86.4 g), total fetuses (14.2 vs. 13.0), and fetus crown-rump length (7.97 vs. 7.66 cm). Supplementation with OG reduced (P = 0.04) individual placenta fluid volume of gilts (150.6 vs. 115.4 mL). PG600 injection increased (P &lt; 0.001) ovary weight (9.03 vs. 10.57 g), total CL (18.09 vs 32.27) and reduced CL weight (0.46 vs. 0.38 g). The results demonstrated classic PG600 responses on reproductive characteristics but no effects of 0.75% OG supplementation nor an interaction between the two factors.

Efficiency of mating, artificial insemination or resynchronisation at different times after first timed artificial insemination in postpartum Nellore cows to produce crossbred calves

2019 ◽  
Vol 59 (2) ◽  
pp. 225 ◽  
Author(s):  
Walvonvitis Baes Rodrigues ◽  
Jean do Prado Jara ◽  
Juliana Correa Borges ◽  
Luiz Orcirio Fialho de Oliveira ◽  
Urbano Pinto Gomes de Abreu ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Breeding Season ◽  
Chorionic Gonadotropin ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Beef Cows ◽  
Device Removal ◽  
Oestradiol Benzoate ◽  
Timed Artificial Insemination ◽  
Equine Chorionic Gonadotropin

The objective of this trial was to evaluate different post-timed artificial insemination (TAI) reproductive managements in postpartum beef cows to produce crossbred calves from artificial insemination (AI). Nellore cows (n = 607), with 45 days postpartum, were inseminated at a fixed time, using a protocol that included an intravaginal progesterone-releasing device along with oestradiol benzoate, prostaglandin, equine chorionic gonadotropin, and oestradiol cypionate, followed TAI 48 h post-device removal. Four post-TAI treatments were evaluated: in CONTROL (T1, n = 161), cows were exposed to Nellore clean-up bulls until the end of the breeding season (75 days). In OBSERVATION (T2, n = 132), heat detection was performed for 15–25 days post-TAI, followed by AI. In RESYNC22 (T3, n = 157) and RESYNC30 (T4, n = 157), resynchronisation started after 22 or 30 days, following second TAI at Day 32 or 40 days after first TAI. In T2, T3 and T4, after the second AI, cows were exposed to Nellore clean-up bulls until the end of the breeding season (75 days). The pregnancy rate (PR) for the first TAI did not differ (54.6%, 53.0%, 59.2%, and 51.6% for CONTROL, OBSERVATION, RESYNC 22, and RESYNC 30, respectively; P = 0.66), and no difference was observed for the second TAI (RESYNC 22 = 45.31% and RESYNC30 = 46.05%; P = 0.137), in the PR at the end of the breeding season (86.33%, 86.36%, 78.98%, and 81.52%, P = 0.43), or embryonic losses (4.54%, 2.85%, 6.45% and 7.40%, respectively; P = 0.61), but the percentage of crossbred pregnancy was higher in groups with resynchronisation (RESYNC22 and RESYNC30) than CONTROL and OBSERVATION (98.38%, 90.62%, 63.30%, 78.95%, P &lt; 0.001). In conclusion, resynchronisation programs of 22 or 30 days are more efficient to produce AI products, and the final pregnancy rate is similar among the treatments, differing only in the amount of calves produced by AI.

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