There Is No Need to Take Embryos Out of the Incubator until the Day of Embryo Transfer

The hormonal regulation of embryo development during early pregnancy in the ewe has been examined. Ovariectomized ewes received injections of oestradiol (E2) and progesterone (P) according to schedules designed to simulate endogenous ovarian secretion during the luteal phase of the previous oestrous cycle (priming P), around the time of oestrus (oestrous E2 ) and during early pregnancy (maintenance P, maintenance E2)' Embryos were transferred to the ewes on the 4th day after induced oestrus, and ewes were killed at 6 or 13 days after transfer to assess embryo development. Cytosol concentrations of oestradiol 'and progesterone receptors and RNA and protein metabolism in the endometrium and amounts of protein in uterine flushings were examined on the day of embryo transfer and 6 days after transfer.

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206 EFFECTS OF A COMBINATION OF A PRID, PGF2α AND eCG, ON ESTRUS SYNCHRONIZATION AND PREGNANCY RATE FOLLOWING EMBRYO TRANSFER IN HOLSTEIN HEIFERS

Reproduction Fertility and Development ◽

10.1071/rdv19n1ab206 ◽

2007 ◽

Vol 19 (1) ◽

pp. 220 ◽

Cited By ~ 3

Author(s):

Y. Aoyagi ◽

A. Ideta ◽

M. Matsui ◽

K. Hayama ◽

M. Urakawa ◽

...

Keyword(s):

Pregnancy Rate ◽

Embryo Transfer ◽

Plasma Concentrations ◽

Pregnancy Rates ◽

Bovine Embryo ◽

Estrus Synchronization ◽

Chi Square ◽

End Of Treatment ◽

Chi Square Analysis ◽

Day Of Embryo Transfer

Successful bovine embryo transfer requires synchronization of luteolysis, estrus and ovulation. The objective of the present study was to evaluate the effect of a combination of a PRID, PGF2� and eCG, on estrus synchronization and pregnancy rate in recipient heifers. A PRID� (ASKA Pharmaceutical Co., Ltd., Tokyo, Japan) was inserted into the vagina at random days of the estrous cycle for 7 (n = 35) or 9 (n = 43) days. Two days before removal of the PRID, the heifers were injected with PGF2� IM (2 mL Resipron�-C containing 0.25 mg mL-1 cloprostenol; ASKA). About half of the heifers in each group received 250 IU eCG IM (Serotropin�; ASKA) at the time of PRID removal. Blood was collected several times from the start of treatment for 7 (n = 9) or 9 (n = 9) days and on the day of embryo transfer by jugular venipuncture; plasma was immediately separated and stored at -20�C until assayed for plasma concentrations of estradiol-17α (E2) and progesterone (P4). The E2 and P4 determinations were performed by enzyme immunoassay after extraction by diethyl ether. Pregnancy was determined by ultrasonography on Day 30 (Day 0 = estrus). The rates of successful standing estrus (no. in estrus/PRID inserted), embryo transfer (no. transferred/estrus), and pregnancy (no. pregnancy/transferred) were compared between groups. Data were analyzed by chi-square analysis or Fisher's PLSD test following ANOVA. Injection of eCG at the time of PRID removal had no significant effect on the rates of successful standing estrus, embryo transfer, or pregnancy (P > 0.05). The proportion of heifers treated for 9 days that exhibited standing estrus (93&percnt;, 40/43) was significantly higher than the proportion of heifers treated for 7 days that exhibited standing estrus (66&percnt;, 23/35, P < 0.01). Of the heifers that were treated for 9 days, the proportion of heifers exhibiting standing estrus within 2 days after the end of treatment was significantly higher (93&percnt;, 37/40) than for heifers that were treated for 7 days (65&percnt;, 15/23; P < 0.01). Pregnancy rates of heifers treated for 9 days (84&percnt;, 32/38) and 7 days (81&percnt;, 17/21) were not significantly different. The E2 : P4 ratio normally increases during follicle growth and CL regression. The plasma E2 : P4 ratio between the time of injection of PGF2α and the time of PRID removal was significantly higher for heifers that were treated for 9 days than it was for heifers that were treated for 7 days (P < 0.01). These results suggest that a combination of PRID treatment for 9 days and injection of PGF2α 2 days before PRID removal successfully synchronized estrus in recipient heifers and led to high pregnancy rates following embryo transfer.

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160 CONCEPTION RATES FOLLOWING TREATMENT OF LACTATING HOLSTEIN RECIPIENTS WITH A GONADOTROPIN RELEASING HORMONE (GnRH) ANALOGUE AT THE TIME OF TRANSFER OF OVUM PICK-UP/IVF-DERIVED EMBRYOS

Reproduction Fertility and Development ◽

10.1071/rdv25n1ab160 ◽

2013 ◽

Vol 25 (1) ◽

pp. 228

Author(s):

T. L. C. Pinto ◽

J. N. S. Sales ◽

R. R. Carvalho ◽

T. M. França ◽

J. C. Souza

Keyword(s):

Dairy Cows ◽

Embryo Transfer ◽

Management Tool ◽

Gnrh Analogue ◽

Gnrh Analogues ◽

Treatment Groups ◽

Lactating Dairy Cows ◽

Conception Rates ◽

Day Of Embryo Transfer

The use of lactating dairy cows as ovum pick-up (OPU)/IVF-derived embryo recipients in large-scale embryo transfer programs may be limited by the effects of low progesterone concentrations on the uterine environment and subsequent embryo development. It was hypothesized that the injection of a GnRH analogue on the day of embryo transfer would induce ovulation and formation of an accessory corpus luteum, increasing progesterone concentrations and, as a result, conception rates. An experiment was designed to evaluate the effects of two different GnRH analogues injected IM on the day of embryo transfer on conception rates of lactating Holstein recipients. Oestrus was not synchronized and was detected continuously by multiple observers during the day and in the evening until midnight. Recipient days in milk varied from 45 to 150, daily milk production ranged from 20 to 45 kg, body condition scores and age ranged from 2.5 to 4.5 and 2.5 to 5.5 years, respectively. Herd pregnancy rates after the first artificial insemination ranged from 15% to 70%, considering the period the experiment was conducted. Embryos were produced by standard in vitro techniques following OPU on Holstein donors. Lactating Holstein recipients (n = 224) were allocated randomly to one of three treatment groups 7 days after detected oestrus: Control (n = 77) = vehicle; Buserelin (Sincroforte®, Ouro Fino, Sao Paulo, Brazil; n = 75) = 10 µg; and Deslorelin (Sincrorrelin®, Ouro Fino; n = 72) = 750 µg. Embryos were transferred nonsurgically 6 to 8 days after observed oestrus. Pregnancy was detected by ultrasonography between 62 and 72 days after embryo transfer. Percent pregnant data were analyzed as a binomial distribution under the GENMOD procedure of SAS (SAS Institute Inc., Cary, NC, USA). Conception rates were similar (P = 0.13) between Control (28%, 22/77), Buserelin (24%, 18/75), and Deslorelin (38%, 28/72) treatment groups. These data demonstrate that conception rates from in vitro produced embryos transferred to lactating dairy cows are not improved by treatment with a GnRH analogue on the day of transfer. Although not critically tested, results indicate that adequate conception rates may be obtained in commercial dairy operations from OPU/IVF-derived embryos, adding an important management tool for reproduction and animal breeding enhancement.

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