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 ◽  
...  

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 & 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's exact, Student'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 > 0.05). The mean diameters of preovulatory follicles were smaller (P < 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 > 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.

2006 ◽  
Vol 18 (2) ◽  
pp. 225
Author(s):  
U. H. Kim ◽  
G. H. Suh ◽  
I. H. Kim

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.


2012 ◽  
Vol 24 (1) ◽  
pp. 115
Author(s):  
J. K. Jeong ◽  
H. G. Kang ◽  
I. H. Kim

This study compared pregnancy rates following 2 timed artificial insemination (TAI) protocols using PGF2α + oestradiol or PGF2α + oestradiol + GnRH in dairy cows. Four hundred fifty-five Holstein dairy cows, 2.2 ± 0.1 in parity, 148.3 ± 3.6 days in milk, with corpus luteum of greater than 20 mm diameter confirmed by ultrasonography (Tringa Linear with 5.0 MHz array transducer; Esaote Pie Medical, Maastricht, the Netherlands) were randomly divided into two treatments: an injection of 500 μg of cloprostenol, PGF2α analogue (Iliren cycle BP®, Intervet International GmbH, Unterschleissheim, Germany) and an injection of 2 mg of oestradiol benzoate (EB, SY Esrone, Samyang, Seoul, Korea) 36 h later (PGF2α + EB group, n = 257), or an injection of 500 μg of cloprostenol, an injection of 2 mg of EB 36 h later and an additional injection of 100 μg of gonadorelin, GnRH analogue (Godorel, Uni-Biotech Co., Ltd., Korea) 24 h later (PGF2α + EB + GnRH group, n = 198). All cows in the two groups received TAI 24 h after the EB injection. Pregnancy was determined at 40 to 50 days after TAI by using both ultrasonography and rectal palpation. Pregnancy rates between the PGF2α + EB and PGF2α + EB + GnRH groups were compared by the chi-square test using the SAS program (version 9.1: SAS Institute Inc., Cary, NC, USA). Pregnancy rate following TAI did not differ between the PGF2α + EB (32.7%) and PGF2α + EB + GnRH groups (34.9%; P > 0.05). In conclusion, addition of GnRH for TAI protocol using PGF2α + oestradiol did not improve pregnancy rate in dairy cows.


2018 ◽  
Vol 44 (1) ◽  
pp. 7
Author(s):  
Laís Mielke ◽  
Mityelle Da Costa Chaves Rodrigues ◽  
Márcio Érpen Lima ◽  
Diego Andres Velasco Acosta ◽  
Francisco Augusto Burkert Del Pino ◽  
...  

Background: Milk production of cows is closely correlated with its reproductive efficiency. One of the several factors influencing the dairy efficiency is the decline in fertility of the cows/heifers. Use of hormonal protocol are often used to improve the fertility of the recipients. Several programs are available to inseminate dairy cows, with variation in the use of different types of hormones, time of use and range of duration period, as well as the time of AI. The objective of this study was to evaluate the efficiency of follicular wave emergence induction of estradiol benzoate in comparison to GnRH in a Heatsynch protocol and its influence on reproductive parameters.Materials, Methods & Results: In this study were used primiparous and multiparous Holstein cows (n = 325). Animals were divided randomly into two different treatments according with the hormone used to induce follicular wave emergence (D0). The GnRH group (n = 167), was given 25 mg, while in the EB group (n = 158) was used 2 mg. At same day, were inserted, a controlled internal drug-releasing containing 1.9 g of progesterone CIDR®. On day 7, CIDR was removed and cows were given 25 mg luteinizing hormone followed by an injection of 1 mg Inducer Ovulation at day 8. Cows were then observed for signs of estrus for at least two hours (twice daily at 7 am and 6 pm) for three days following CIDR® removal. Cows detected in estrus were inseminated 12 h later the estrus detection. Pregnancy status was determined by ultrasonography at 30 ± 5 d and 60 ± 5 d after AI. A single technician was responsible for the estrus detection and inseminations. A single technician was responsible for the estrus detection and inseminations. Ultrassonographic examinations with ultrasound, transrectal linear probe of 5 MHz, were performed for the diagnosis of pregnancy at 30 and 60 days after artificial insemination. Binomially distributed data, such as, estrous response, conception rate, pregnancy rate and pregnancy losses, were analyzed by Chi-square test. Pregnancy rates at 30-35 days and 60-65 days as well as pregnancy losses were considered in the model for the effect of parity (primiparous vs. multiparous) and the group of estrus behavior during the Heatsynch protocol. Conception rate was similar between GnRH (36.1%, 57/158) and EB (37.7%, 63/167) treatments. Cows showing estrus signs after CIDR removed were 71.9% in GnRH and 62% in EB group (P = 0.05). Embryonic losses were different (P = 0.03) according to groups of cows showing estrus signals or not.Discussion: Our results demonstrate that conception rates are not affected by using either EB or GnRH at the beginning of the Heatsynch protocol. Therefore, the EB can be an alternative choice to GnRH at Heatsynch beginning. Similar results were found by autor in dairy cows, once it was also observed that there is no difference in conception rate in two TAI protocols using either GnRH or EB. In Heatsynch protocols the increase in estrus detection are a key factor to increase fertility in lactating dairy cows. It can be explained once animals in regular estrous cycle have a palpable corpus luteum and circulating progesterone concentration higher than 1 ng/mL which leads than to enhance pregnancy ratios. The use of BE at the time of CIDR insertion in TAI protocols for dairy cattle proved to be an alternative to GnRH considering conception rates. Therefore, the use of BE at the time of CIDR insertion in a Heatsynch protocol in dairy cattle proved to be an alternative to GnRH which can be an important tool to increase the TAI utilization by farmers. Furthermore, in Heatsynch protocol cows showing estrus have pregnancy rates improved and lower pregnancy losses.


2005 ◽  
Vol 17 (2) ◽  
pp. 158
Author(s):  
U.H. Kim ◽  
G.H. Suh ◽  
I.H. Kim

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.


2007 ◽  
Vol 19 (1) ◽  
pp. 223
Author(s):  
T. Okazaki ◽  
E. Sasaki ◽  
K. Hasegawa ◽  
T. Takani ◽  
S. Abe

Recent studies have shown that the presence of accessory or multiple corpora lutea (CL) and increased progesterone (P4) concentrations reduced early embryonic mortality in cattle. The objective of this study was to evaluate the effect of equine chorionic gonadotropin (eCG) treatment on the number of CL, the P4 concentrations, and pregnancy rates after embryo transfer (ET). Holstein heifers (n = 120) from 7 dairy farms received an intravaginal progesterone-releasing device (CIDR; InterAg, Hamilton, New Zealand) and 2 mg IM of estradiol benzoate (EB; Gynandol®; Sankyo, Tokyo, Japan) at random stages of the estrous cycle. After 7 to 9 days, CIDRs were removed and 15 mg of prostaglandin F2α (PG; Pronalgon®; Pfizer Japan, Nagoya, Japan) were administered, followed by 100 µg IM GnRH (Conceral®; Takeda Pharmaceutical Co., Ltd., Osaka, Japan) 2 days later (Day 0). The heifers were placed at random into 3 groups for eCG treatment. The eCG was not administered in a control group (n = 53); heifers in other 2 groups received 1000 IU eCG (Peamex®; Sankyo, Japan) IM at the time (0 h group, n = 37) or 48 h before (48 h group, n = 30) PG injection/CIDR removal. On Day 7, heifers were examined by ultrasonography (Aloka SSD500; Aloka, Tokyo, Japan) for number of CL; heifers with at least one functional CL received an in vivo-derived frozen–thawed embryo by direct transfer. At the same time, a blood sample was collected to determine P4 concentration. Pregnancy rates were determined on Days 30 and 60 by ultrasonography and rectal palpation, respectively. The data were analyzed by ANOVA and means were compared with Fisher's PLSD. Proportional data were analyzed by the chi-square test. P4 concentrations (mean ± SD) on Day 7 were 1.8 ± 1.0, 5.6 ± 3.3, and 2.2 ± 1.1 ng mL−1 for the control, 48 h, and 0 h groups, respectively (48 h vs. control and 0 h; P &lt; 0.001). The number of CL on Day 7 were 1.1 ± 0.4, 2.5 ± 1.4, and 1.8 ± 0.9 for the control, 48 h, and 0 h groups, respectively (control vs. 48 h and 0 h, and 48 h vs. 0 h; P &lt; 0.01). Pregnancy rates did not differ between 0 and 48 h groups but both were higher than in the control group (Table 1). Results suggest that the estrus synchronization protocol with administration of eCG at the time of CIDR removal or 48 h earlier significantly increased the number of CL and the P4 concentration, and improved pregnancy rates in Holstein heifers after ET. Table 1.Pregnancy rates of Holstein heifers synchronized with CIDR and PG and treated with eCG


2006 ◽  
Vol 18 (2) ◽  
pp. 116 ◽  
Author(s):  
D. Maraña ◽  
L. Cutaia ◽  
L. Peres ◽  
D. Pincinato ◽  
L. F. K. Borges ◽  
...  

Two experiments were designed to compare the effects of eCG treatment and temporary weaning on ovulation and pregnancy rates in postpartum cows. In Experiment 1, 39 lactating multiparous crossbred Bos indicus cows, 60 to 80 d postpartum with a body condition score (BCS) between 2.0 to 2.5 out of 5 were randomly allocated to one of four treatment groups in a 2 � 2 factorial design. On Day 0, all cows received a progesterone (P4) intravaginal device (DIB; Syntex, Argentina) and 2 mg estradiol benzoate (EB) i.m. (Syntex). On Day 8, DIB devices were removed and all cows received 150 �g D(+)cloprostenol i.m. (Ciclase; Syntex) and were randomly divided to receive 400 IU eCG i.m. (Novormon 5000; Syntex) at the same time or no treatment. In addition, half of the cows in each group had their calves weaned temporarily (TW) for 56 h at the time of DIB removal; the other half remained with their calves. All cows received 1 mg EB i.m. on Day 9 and were examined every 8 h by ultrasonography from the time of DIB removal until ovulation. Data were analyzed by ANOVA and chi-square test. The diameter of the dominant follicle on Day 8 (eCG: 7.8 � 0.5 mm vs. no eCG: 8.2 � 0.4 mm, and TW: 7.6 � 0.4 mm vs. no TW 8.4 � 0.5 mm), the proportion of cows that ovulated (eCG: 12/20, 60% vs. no eCG: 9/19, 47%; and TW: 13/20, 65% vs. no TW: 8/19, 42%, and the interval to ovulation (eCG: 72.0 � 1.4 h vs. no eCG: 75.6 � 2.0 h, and TW: 73.8 � 1.6 h vs. no TW: 73.0 � 1.8 h) did not differ among groups (P > 0.05). Although there was no effect of eCG treatment or eCG by TW interaction (P > 0.3) on the size of the preovulatory follicle (eCG: 11.1 � 0.4 mm vs. no eCG: 10.1 � 0.6 mm), it was smaller in cows TW (9.9 � 04 mm), compared to those not TW (11.8 � 0.3 mm; P < 0.05). Nevertheless, the growth rate of the ovulatory follicle was greater (P < 0.02) in cows treated with eCG (1.1 � 0.1 mm/day) than in those not treated with eCG (0.6 � 0.1 mm/day). In Experiment 2 769 lactating multiparous crossbred Bos indicus cows received the same treatments as those in Experiment 1 and were fixed-time inseminated (FTAI) 52 to 56 h after DIB removal. Cows were examined by ultrasonography on Day 0 (22.5% with corpora lutea (CL), 30.0% with follicles >8 mm, and 47.5% with follicles <8 mm) and 42 d after FTAI to determine pregnancy. Data were analyzed by logistic regression. Pregnancy rates were not affected (P > 0.7) by TW (TW: 141/397, 37.2% vs. no TW: 141/390, 36.1%) or the TW by eCG interaction (P > 0.7). However, pregnancy rates were higher (P < 0.05) in cows treated with eCG (154/377, 40.8%) than in those not treated with eCG (128/392, 32.6%). The use of eCG but not TW improved pregnancy rates following FTAI in postpartum Bos indicus cows. Results also suggest that the eCG-related increase in pregnancy rates may be due to the final growth rate of the ovulatory follicle.


2012 ◽  
Vol 24 (1) ◽  
pp. 115
Author(s):  
J. K. Jeong ◽  
H. G. Kang ◽  
I. H. Kim

This study determined the effect of supplementation with oestradiol or oestradiol plus GnRH after PGF2α administration on pregnancy rates after timed artificial insemination (TAI) in dairy cows. Three hundred and six Holstein dairy cows with corpus luteum confirmed by ultrasonography (Tringa Linear with 5.0 MHz array transducer; Esaote Pie Medical, Maastricht, the Netherlands) were randomly allocated to three treatments: a single injection of 500 μg of cloprostenol, PGF2α analogue (Estrumate, Schering-Plough Animal Health, Friesoythe, Germany; PGF2α group, n = 115) designated as 0 h, an injection of 500 μg of cloprostenol and an injection of 1 mg of oestradiol benzoate (EB, SY Esrone; Samyang, Seoul, Korea) 56 h later (PGF2α + EB group, n = 114), or the same treatment as in the PGF2α + EB group and an additional injection of 100 μg of gonadorelin, GnRH analogue (Godorel, Uni-Biotech Co., Ltd., Korea) 24 h later (PGF2α + EB + GnRH group, n = 77). All cows in each group received TAI 80 h after the PGF2α injection. Pregnancy was determined at 40 to 50 days after TAI by using both ultrasonography and rectal palpation. Pregnancy rate among groups were compared by the chi-square test using the SAS program (version 9.1: SAS Institute Inc., Cary, NC, USA). Pregnancy rate following TAI were higher (P < 0.05) in the PGF2α + EB + GnRH group (34/77, 44.2%) than in the PGF2α group (31/115, 27.0%), with the PGF2α + EB group intermediate (39/114, 34.2%). In conclusion, the supplementation with oestradiol plus GnRH after PGF2α administration improved pregnancy rate after TAI in dairy cows. This work was supported by the research grant of the Chungbuk National University in 2011.


2020 ◽  
Vol 8 (3) ◽  
pp. 100-103

The repeat breeding condition affects both the fertility of cows and the economy of farmers and the nation. Normal levels of various biochemical constituents are indispensable for the normal functioning of various body systems of animals, including the reproductive system. The hormonal profile is an indicator of the reproductive status and aids in the prognosis and restoration of animal fertility. The present study explores the implication of four hormones (luteinizing hormone, follicle-stimulating hormone, human chorionic gonadotropin and prolactin) on the normal cycle breeding process of Bangladeshi normal cyclic cows and repeat breeder dairy cows. Among four hormones, the levels of luteinizing hormone and prolactin were significantly different between the normal cyclic cows and repeat breeder cows. The assessment of hormonal profile aids in ameliorating the repeat breeding conditions of the dairy cows. The findings of the present study could be applied in overcoming repeat breeding problems in dairy cows and thus, economic loss could be lessened.


2010 ◽  
Vol 22 (1) ◽  
pp. 300
Author(s):  
T. Miyauchi ◽  
C. A. C. Fernandes ◽  
E. R. Oliveira ◽  
B. F. L. Alves ◽  
J. H. M. Viana

Transvaginal guided follicle aspiration (TGFA) is the main technique used in Brazil to recover oocytes for in vitro embryo production (IVP) in bovine. Different protocols have been proposed to synchronize follicular emergence in oocyte donors, but most of them were developed for use in European breeds of cattle, which show many differences in ovarian physiology when compared with Zebu breeds. The aim of this study was to compare different protocols for preparation of Gyr (dairy zebu breed) oocyte donors. The TGFA were performed in a donor management facility located in Minas Gerais State, southeast Brazil. Pluriparous cycling Gir cows (n = 42) were used as donors. All cows underwent 3 treatments: G1 (control), no treatment before TGFA; G2, 2 mg of estradiol benzoate (EB) for follicular wave synchronization given i.m. 5 days before TGFA; and G3, norgestomet auricular implants given 9 days and 2 mg of EB plus 0.53 mg of cloprostenol given 5 days before TGFA. The interval between TGFA in the same donor was greater than 30 days. All procedures were made by the same technician, using a portable ultrasound device, disposable 19G or 20G needles, and a vacuum pressure of 80 mm Hg. The aspirated follicular fluid was collected in 50-mL Falcon tubes and sent to the laboratory for COC identification and classification under 50 × magnification. Recovered oocytes were classified according to cumulus cell layers and cytoplasm morphology. The total number of oocytes and viable COC recovered and the procedure length (min), including time spent for TGFA and laboratory manipulation, were compared. Data were evaluated by ANOVA, and means compared by Tukey’s test. A total of 126 TGFA sessions were performed, with recovery of 2,809 oocytes (20.31 ± 12.32 of COC and 14.83 ± 7.97 of viable COC per cow/session; mean ± SD). The total number of recovered oocytes and viable COC recovered were lower in G1 compared with G2 and G3 (15.18 ± 11.07 v. 21.18 ± 9.71 and 24.68 ± 9.03; and 9.53 ± 7.22 v. 16.97 ± 6.47 and 18.84 ± 8.90, respectively; P < 0.05) There was no difference (P > 0.05) between G2 and G3 on the number of oocytes or viable COCs recovered. The procedure length, however, was longer in G1 and G2 compared with G3 (49.6 ± 15.1 and 46.9 ± 13.4 v. 35.8 ± 13.1 min, respectively; P < 0.05) The shorter procedure length in G3 was probably associated with the reduced number of cows showing no corpora lutea (38/42, 90%), which resulted in reduction of bleeding and clot formation in the aspirated fluid. These results show that (1) previous follicular wave synchronization by EB can improve the number and quality of recovered oocytes; (2) the absence of corpora lutea does not increase the number of recovered COC and viable COC, but reduces the time spent in the procedure. Intervet Schering Plough Animal Health.


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