scholarly journals 9THE USE OF ECG TO INCREASE PREGNANCY RATES IN POSTPARTUM BEEF COWS FOLLOWING TREATMENT WITH PROGESTERONE VAGINAL DEVICES AND ESTRADIOL BENZOATE AND FIXED-TIME AI

2004 ◽  
Vol 16 (2) ◽  
pp. 127 ◽  
Author(s):  
G.A Bo ◽  
L. Cutaia ◽  
P. Chesta ◽  
D. Moreno
Keyword(s):  
Body Condition Score ◽  
Fixed Time ◽  
Beef Cows ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Control Group ◽  
Treatment Groups ◽  
Condition Score ◽  
N 93 ◽  
Rectal Palpation

Treatments with progesterone (P4) releasing devices and estradiol benzoate (EB) have been extensively used in fixed-time AI (FTAI) programs in beef cattle. However, pregnancy rates in postpartum cows kept on pasture often have been lower than expected because of poor body condition score (BCS) and a high incidence of anestrous. A recent study (Cutaia L et al., 2003 Theriogenology 59, 216) suggested that the addition of eCG to a P4/EB FTAI program may improve pregnancy rates in cows with fair to poor BCS, but results were not conclusive. Therefore, this experiment was designed to further investigate the effect of eCG treatment on pregnancy rates in postpartum beef cows in those conditions. The experiment was performed at 2 locations with lactating Angus cows (n=93), 60 to 90d postpartum with a BCS 1.9 (1 to 5 scale; Location 1), and crossbred Zebu cows (n=290), 60 to 90d postpartum with a BCS 2.0 (Location 2). In each Location, cows were randomly allocated to 1 of the following treatment groups: Control, eCG Day6, or eCG Day8. All cows received a P4 intravaginal device (DIB, Syntex, Argentina) and 2mg EB i.m. (Syntex) on Day0, 500mg cloprostenol (Estroplan, Syntex) at the time of DIB removal (Day8), 1mg EB i.m. on Day9 and FTAI 52 to 56h after DIB removal. Cows in the Control group received no further treatment, whereas cows in the eCG-treated groups received 400 IU eCG (Novormon 5000, Syntex) on Day6 or Day8. Cows were examined on Day0 by rectal palpation (Location 1) or by ultrasonography (US; Location 2) and were classified as those with a CL or without a CL, with either large (>8mm) or small (<8mm)small follicles. Pregnancy was determined by US 45d after FTAI. Data were analyzed by logistic regression and the effects of location, treatment, ovarian status, AI technician and semen were considered in the model. There was no effect of location (P=0.3), AI technician (P=0.2) or semen (P=0.8) on pregnancy rates. However, there was an effect of treatment (P=0.02), attributed to higher pregnancy rates in the eCG Groups than in the Control Group (Table). Furthermore, cows with a CL or without a CL but with large follicles on Day 0 had higher pregnancy rates than those with small follicles (P=0.04). It was concluded that the use of eCG in a P4/EB FTAI program improved pregnancy rates in postpartum beef cows that were in fair topoor BCS.

scholarly journals 14 EFFECT OF TEMPORARY WEANING AND ECG TREATMENT ON PREGNANCY RATES IN POSTPARTUM BOS INDICUS COWS FOLLOWING TREATMENT WITH PROGESTERONE VAGINAL DEVICES AND ESTRADIOL BENZOATE

2005 ◽  
Vol 17 (2) ◽  
pp. 157
Author(s):  
L. Cutaia ◽  
E. Balla ◽  
C. Rizzi ◽  
L. Peres ◽  
G.A. Bo
Keyword(s):  
Body Condition Score ◽  
Bos Indicus ◽  
Fixed Time ◽  
Beef Cows ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Medium Size ◽  
Ovarian Activity ◽  
Condition Score ◽  
Rectal Palpation

Although treatments with progesterone (P4)-releasing devices and estradiol benzoate (EB) have been extensively used in fixed-time AI (FTAI) programs in beef cattle, pregnancy rates in postpartum Bos indicus cows kept on pasture often have been lower than expected because of poor body condition score (BCS) and a high incidence of anestrus. Temporary weaning and eCG treatment have been shown to increase pregnancy rates in suckled beef cows. Therefore, this experiment was designed to compare the effect of eCG treatment and temporary weaning on pregnancy rates in postpartum cows in fair to poor BCS. Lactating multiparous crossbred Bos indicus cows (n = 393), 60 to 90 d postpartum with a BCS 2.0 (1 to 5 scale) were randomly allocated to 1 of 4 treatment groups, in a 2 × 2 factorial design. At the beginning of the experiment (Day 0), all cows received a P4 intravaginal device (DIB, Syntex, Argentina) and 2 mg EB i.m. (Syntex). On Day 8, DIB devices were removed and all cows received 150 μg D (+) cloprostenol i.m. (Ciclase, Syntex) and were randomly divided to receive 400 IU eCG (Novormon 5000, Syntex) or no treatment at the same time. Furthermore, half of the cows in each treatment group have their calves weaned temporarily, from the time of DIB removal until the end of the FTAI, whereas the other half remained with their calves all the time. Finally, all cows received 1 mg EB i.m. on Day 9 and were FTAI 52 to 56 h after DIB removal. Cows were examined by ultrasonography 42 d after FTAI to determine pregnancy status. Data were analyzed by logistic regression and the effects of treatment and semen used were considered in the model. Ovarian activity was estimated by rectal palpation on Day 0: there were 72/393 (18.2%) cows with a CL, 140/393 (35.6%) cows with palpable medium size follicles, and 181/393 (46.1%) cows with ovaries containing no detectable structures. There was no effect of ovarian status at the time of treatment (P = 0.91) or semen (P = 0.91) on pregnancy rates. Treatment with eCG tended (P = 0.08) to increase pregnancy rates (94/192, 48.9% and 79/201, 39.3% for cows treated or not treated with eCG, respectively). However, there was no effect of weaning or eCG by weaning interaction (P = 0.98) on pregnancy rates (86/191, 45.1% and 87/202, 43.1% for cows that have their calves weaned or not weaned for 56 h, respectively). Results confirm those of previous studies that demonstrated that the use of eCG in a P4/EB/FTAI program improved pregnancy rates in postpartum Bos indicus crossbred cows that were in fair-to-poor BCS. However, no improvement in pregnancy rates was observed after temporary weaning in the present study. Research was supported by Syntex S.A., Estancia El Mangrullo S.A., and Agencia Cordoba Ciencia S.E.

20 PREGNANCY RATES IN SUCKLED BEEF COWS SYNCHRONIZED WITH PROGESTERONE INTRAVAGINAL DEVICES AND RECEIVING eCG FOURTEEN DAYS AFTER BREEDING

2010 ◽  
Vol 22 (1) ◽  
pp. 168 ◽  
Author(s):  
L. Cutaia ◽  
M. Ramos ◽  
P. Chesta ◽  
G. A. Bó
Keyword(s):  
Body Condition ◽  
Bos Taurus ◽  
Body Condition Score ◽  
Bos Indicus ◽  
Fixed Time ◽  
Beef Cows ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Treatment Groups ◽  
Condition Score

An experiment was designed to test the following hypotheses: (1) the administration of 400IU of eCG (Novormón, Syntex SA, Buenos Aires, Argentina) 14 days after fixed-time artificial insemination (FTAI) increases pregnancy rates in cross-breed Zebu × Bonsmara suckled cows synchronized with progesterone releasing devices (DIB 0.5, 0.5 g of progesterone, Syntex SA); and (2) pregnancy rates in cows treated with estradiol or GnRH, combined with a DIB device, are not different. Primiparous suckled cows (n = 260), between 60 and 120 days postpartum (DPP) and with a body condition score between 2.0 and 2.5 (1 to 5 scale) were used. At the beginning of the experiment (Day 0), all cows were examined by rectal palpation (only 11% had a CL), received a DIB device, and were randomly allocated to 1 of 3 treatment groups. Cows in the E2 group received 2 mg of estradiol benzoate (EB) intramuscularly (i.m.) at DIB insertion and those in the two GnRH groups received 100 μg of gonadorelin (GDR Gonasyn, Syntex SA) at the same time. On Day 7, DIB devices were removed and all cows received 500 μg of cloprostenol (Ciclase DL, Syntex SA) plus 400 IU of eCG (i.m.). Cows in the E2 group received 0.5 mg of estradiol cypionate (ECP, Cipiosyn, Syntex SA) and underwent FTAI administered by one technician, using semen from 1 of 2 bulls between 52 and 56 h later. Cows in the GnRH groups received a dose of 100 μg of gonadorelin (full GnRH group) or 50 μg of gonadorelin (1/2 GnRH group) at the time of the FTAI (52 to 56 h after DIB removal). Fourteen days after FTAI cows in the 3 groups were further subdivided (3 × 2 factorial) to receive or not 400 IU of eCG i.m. Pregnancy was determined 30 days after FTAI using real-time ultrasonography. Data were analyzed by logistic regression, taking into account the effect of the synchronization treatment, eCG or noteCG, 14 days after FTAI and sire used. No differences in pregnancy rates were found (P = 0.16) among treatment groups (E2: 39/87, 43.7%, full GnRH: 38/92, 41.3%, and 1/2 GnRH: 25/81, 30.9%). However, there was a significant (P = 0.02) effect of eCG treatment 14 days after FTAI (eCG: 60/127, 47.2% v. no eCG: 41/133, 30.8%). Furthermore, bull A (77/155, 47.1%) resulted in higher pregnancy rate (P = 0.009) than bull B (28/107, 26.2%), but there were no significant interactions between bull and synchronization treatment or eCG administration 14 days after FTAI (P > 0.1). We conclude that the application of 400 IU of eCG 14 days after FTAI increases pregnancy rates in suckled Bos taurus × Bos indicus primiparous cows with fair to poor body condition score synchronized with progesterone releasing devices. Furthermore, the use of estradiol ester or GnRH at DIB insertion and removal did not affect pregnancy rates.

39 EFFECT OF TIME OF FIXED-TIME AI ON PREGNANCY RATES IN ZEBU CROSS-BRED BEEF HEIFERS TREATED WITH PROGESTERONE RELEASING DEVICES AND ESTRADIOL CYPIONATE

2010 ◽  
Vol 22 (1) ◽  
pp. 177 ◽  
Author(s):  
M. Ramos ◽  
L. Cutaia ◽  
P. Chesta ◽  
G. A. Bó
Keyword(s):  
Bos Taurus ◽  
Body Condition Score ◽  
Bos Indicus ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Beef Heifers ◽  
Treatment Groups ◽  
Condition Score ◽  
To Receive

Two experiments were designed to evaluate the effect of the timing of fixed-time AI (FTAI) in relation to the removal of an intravaginal progesterone-releasing device (1 g of progesterone, DIB, Syntex SA, Buenos Aires, Argentina) on pregnancy rates in Bos indicus × Bos taurus cross-bred heifers. In experiment 1, 285 Bonsmara × zebu cross-bred heifers, between 18 and 24 months of age and with a body condition score (BCS) between 3.0 and 3.5 (1-5 scale) were used. On the day of initiation of treatment (Day 0), the heifers’ ovaries were palpated (92% of them had a CL) and they received a new DIB plus 2 mg of estradiol benzoate (EB; Syntex SA) and 250 μg of cloprostenol (Ciclase DL, Syntex SA). On Day 8, DIB devices were removed and all heifers received 250 μg of Ciclase plus 0.5 mg of estradiol cypionate (ECP; Cipiosyn, Syntex SA). At that time the heifers were randomly divided to receive FTAI between 48 to 49 h, 53 to 54 h, or 58 to 59 h after DIB removal. The heifers underwent FTAI with semen from 4 bulls by 2 inseminators. In experiment 2, 260 heifers from the same group as those used in experiment 1 (87% with a CL) were treated exactly as those in experiment 1, except that previously used DIB was inserted on Day 0. Pregnancy diagnosis was performed 30 days post-fixed-time AI by ultrasonography. The data were analyzed by logistic regression, taking into account the effect of time of FTAI, semen, and inseminator on pregnancy rates. In experiment 1, pregnancy rates were lower (P = 0.04) in the heifers undergoing FTAI between 48 and 49 h after DIB removal (46/95, 48.4%) than those undergoing FTAI 53 to 54 h (61/99, 61.6%) or 58 to 60 h (57/91, 62.6%) after DIB removal. However, no differences in pregnancy rates were found (P = 0.72) in experiment 2 between the 3 treatment groups, with 39/91 (42.9%) for the 48 to 49 h group, 45/89 (50.6%) for the 53 to 54 h group, and 35/89 (43.8%) for the 58 to 59 h group. There was no effect of the semen or inseminator (P > 0.2) in either experiment. We conclude that when Bos indicus × Bos taurus beef heifers are synchronized with new DIB devices and ECP, higher pregnancy rates are obtained in heifers undergoing FTAI late (between 53 to 60 h after DIB removal) than in those undergoing FTAI early (48 to 49 h after DIB removal). However, time of insemination does not apparently affect pregnancy rates when Bos indicus × Bos taurus beef heifers are synchronized with previously used DIB devices and ECP.

214 EFFECT OF TIMING OF PGF, eCG, AND ESTRADIOL BENZOATE IN RECIPIENTS SYNCHRONIZED WITH A PROGESTIN-BASED PROTOCOL FOR FIXED-TIME EMBRYO TRANSFER

2007 ◽  
Vol 19 (1) ◽  
pp. 224
Author(s):  
L. C. Peres ◽  
D. Pincinato ◽  
L. Cutaia ◽  
R. Tribulo ◽  
G. A. Bo
Keyword(s):  
Embryo Transfer ◽  
Body Condition Score ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Control Treatment ◽  
Treatment Groups ◽  
Condition Score ◽  
The Mean ◽  
Time Of Administration

An experiment was designed to evaluate alternative treatment protocols for fixed-time embryo transfer (FTET) in recipients in order to reduce cattle handling. Non-lactating, cycling Bos taurus � Bos indicus beef cows (n = 918), with a body condition score (BCS) of 2.5 to 3.5 out of 5, received a progesterone-releasing device (DIB; Syntex, Buenos Aires, Argentina) and 2 mg estradiol benzoate (EB; Syntex) IM on random days of the cycle (Day 0); DIB were removed on Day 8. Cows were placed randomly into 6 treatment groups in a 3 � 2 factorial design. The factors evaluated were time of administration of PGF and eCG [control treatment: PGF Day 5 and eCG Day 5 (Bo et al. 2002 Theriogenology 57, 53–72); PGF Days 0 and 8 and eCG Day 5; PGF Days 0 and 8 and eCG Day 8] and the time of administration of the second injection of EB (at DIB removal or 24 h later). Therefore, cows in the control treatment received 150 �g of d-Cloprostenol (PGF, Ciclase; Syntex) and 400 IU eCG (Novormon; Syntex) on Day 5, whereas cows in the other 2 treatments received 75 �g of PGF on Days 0 and 8 and 400 IU eCG on either Day 5 or Day 8. Each treatment group was further subdivided to receive 1 mg EB IM on either Day 8 (EB Day 8) or Day 9 (EB Day 9). All recipients, whether observed in estrus or not and with more than one CL with luteal area (total CL area minus cavity area) >76 mm2 on the day before embryo transfer, received frozen-thawed embryos (IETS Grade 1) on Day 16 (EB Day 8) or Day 17 (EB Day 9) by direct transfer. Pregnancy was determined by ultrasonography 30 days after FTET. Continuous data were analyzed by ANOVA and pregnancy rates were analyzed by logistic regression. No effects of body condition score or technician were detected (P > 0.1). Although there were no differences in conception rates between recipients treated with EB on Day 8 or Day 9 (168/321, 52.3% vs. 203/350, 58.0%, respectively; P > 0.1), treatment with EB on Day 8 resulted in fewer recipients selected/treated (321/460, 69.7% vs. 350/458, 76.4%; P < 0.05) and pregnant/treated (168/460, 36.5% vs. 203/458, 44.3%; P < 0.05) than 24 h later (EB Day 9), respectively. The mean interval from DIB removal to estrus was shorter (P < 0.05) for recipients in the EB Day 8 (28.1 � 7.2 h) than in the EB Day 9 (43.5 � 9.4 h) group, and the mean (� SEM) CL area was also less in the EB Day 8 group than in the EB Day 9 group (261.7 � 96.7 vs. 293.1 � 114. mm2; P < 0.05). The number of recipients selected/treated was higher in the group receiving PGF on Days 0 and 8 and eCG on Day 8 (243/305, 79.6%) than in the group receiving PGF on Days 0 and 8 and eCG on Day 5 (208/301, 69.1%) or the control group (220/312, 70.5%). Although the luteal area was greater (P < 0.05) in the PGF on Days 0 and 8 and eCG on Day 5 group (304.4 � 127.1 mm2) than in the groups receiving PGF and eCG on Day 5 (274.6 � 98.6 mm2) or PGF on Days 0 and 8 and eCG Day 8 (258.4 � 90.2 mm2), pregnancy rates did not differ between PGF and eCG treatment groups (P > 0.05). It was concluded that it may be possible to reduce animal handling by treating recipients with a half dose of PGF at the time of DIB insertion and removal, when eCG is also administered, without compromising pregnancy rates.

12 THE EFFECT OF PROGESTERONE CONTENT IN A VAGINAL INSERT ON PREGNANCY RATES IN BEEF AND DAIRY CATTLE INSEMINATED AT FIXED TIME

2006 ◽  
Vol 18 (2) ◽  
pp. 114
Author(s):  
L. Cutaia ◽  
M. Aviles ◽  
F. Feresin ◽  
A. Franzoni ◽  
L. Peres ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Body Condition Score ◽  
Fixed Time ◽  
Beef Cows ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Holstein Cows ◽  
Chi Square ◽  
Condition Score ◽  
Chi Square Test

Three experiments were conducted to compare pregnancy rates in cows and heifers treated with intravaginal progesterone (P4)-releasing devices impregnated with either 0.5 or 1.0 g of P4 and inseminated at a fixed time (FTAI). In Experiment 1, 102 postpartum beef cows (Hereford and Angus crossbred with Tuli, 60 to 90 d postpartum) with a body condition score (BCS) of 2.5 to 3.0 (1 to 5 scale) were used. On Day 0, all cows received 2 mg of estradiol benzoate (EB; Syntex, Argentina) i.m. and were randomly assigned to receive an intravaginal progesterone-releasing device with 0.5 g of P4 (DIB 0.5 g; Syntex) or 1.0 g of P4 (DIB 1.0 g; Syntex). On Day 7, DIB devices were removed and all cows received 150 µg D(+)cloprostenol (Ciclase; Syntex) i.m. On Day 8, all cows received 1 mg EB and were FTAI 52 to 56 h after DIB removal. In Experiment 2, 93 Holstein cows that were 90 to 110 days in milk (DIM), producing on average 5000 kg of milk per lactation and with a BCS of 2.5 to 3.0 received the same treatments as those in Experiment 1. In Experiment 3, 100 Holstein heifers, 20 to 22 months old, with a BCS of 2.5 to 3.0, also received the same treatments as those in Experiment 1. Pregnancy rates in all experiments were determined by ultrasonography 35 days after FTAI and compared by chi-square test. No differences in pregnancy rates were detected between lactating beef cows, dairy cows, or dairy heifers treated with DIB devices impregnated with 0.5 or 1.0 g of P4 (Table 1). It was concluded that vaginal P4 releasing devices impregnated with 0.5 g or 1.0 g of P4 results in comparable pregnancy rates in FTAI protocols in beef and dairy cattle. Table 1. Pregnancy rates in postpartum beef cows, Holstein cows, and Holstein heifers treated with DIB devices impregnated with 0.5 or 1.0 g of P4 and subjected to FTAI

scholarly journals 8 EFFECT OF SUCKLING RESTRICTION AND eCG TREATMENT ON PREGNANCY RATES IN POSTPARTUM BOS INDICUS CROSSBRED COWS TREATED WITH PROGESTERONE VAGINAL DEVICES AND ESTRADIOL BENZOATE

2005 ◽  
Vol 17 (2) ◽  
pp. 154
Author(s):  
E. Balla ◽  
L. Cutaia ◽  
C. Rizzi ◽  
L. Peres ◽  
G.A. Bo
Keyword(s):  
Body Condition Score ◽  
Bos Indicus ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Medium Size ◽  
Ovarian Activity ◽  
Condition Score ◽  
Student’S T ◽  
Rectal Palpation

Previous studies have shown that the use of eCG given at the time of removal of a progesterone (P4) releasing device improved pregnancy rates to fixed-time AI (FTAI) in postpartum Bos indicus cows (Bo GA et al. 2004 Reprod. Fertil. Dev. 16, 127). Suckling restriction with the placement of nose tags in calves has also been shown to induce cyclicity and increase pregnancy rates in postpartum Bos indicus cows (Stahringer RC 2003 Taurus 18, 21–23). An experiment was designed to compare the effect of eCG treatment and restricted suckling on pregnancy rates in postpartum cows in fair to poor body condition score (BCS). A secondary objective was to evaluate the effect of restricted suckling on weaning weights. Lactating primiparous crossbred Bos indicus cows (n = 399), 60 to 90 days postpartum with a BCS 2.0 (1 to 5 scale), were randomly allocated to 1 of 4 treatment groups, in a 2 × 2 factorial design. On Day 0, all cows received a 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 μg D(+)cloprostenol i.m. (Ciclase, Syntex) and were randomly divided to receive 400 IU eCG (Novormon, Syntex) or no treatment at the same time. On Day 9, all cows received 1 mg EB i.m. and were FTAI 52 to 56 h after DIB removal. Nose tags were placed in half of the calves from Day 0 to the time of FTAI, whereas the other half of the calves remained untreated. All cows were examined by ultrasonography 30 d after FTAI to determine pregnancy status. Pregnancy data were analyzed by logistic regression, and birth and weaning weights were analyzed by Student's t-test. Ovarian activity was estimated by rectal palpation on Day 0: there were 57/399 (14.3%) cows with a CL, 203/399 (50.8%) cows with palpable medium size follicles, and 139/399 (34.8%) cows with ovaries containing no detectable structures. There was no effect of ovarian status at the time of treatment (P = 0.52) or semen (P = 0.89) on pregnancy rates. Suckling restriction increased (P = 0.03) pregnancy rates (91/195, 46.6% and 81/204, 39.7% for cows not suckled or suckled during the treatment, respectively). However, there was no effect of eCG or eCG by weaning interaction (P = 0.82) on pregnancy rates (82/192, 42.7% and 90/207, 43.4% for cows treated or not treated with eCG, respectively). Although mean (±SEM) birth weights were not different (29.4 ± 0.4 vs. 29.1 ± 0.4; P = 0.6), weaning weights were significantly affected (P = 0.001) by the suckling restriction (190.1 ± 1.9 vs. 200.4 ± 2.1 for calves treated or not treated with the nose tags, respectively). Although restricting suckling, by placement of a nose tag from Day 0 to FTAI, may increase pregnancy rates in primiparous Bos indicus cows in fair to poor BCS, the adverse effect of this treatment on weaning weights of the calves has to be considered. Furthermore, eCG did not increase pregnancy rates in the present study, as it has been previously reported. Research was supported by Syntex S.A., Estancia El Mangrullo S.A., and Agencia Cordoba Ciencia S.E.

8 EFFECT OF DURATION OF TREATMENT WITH PROGESTERONE VAGINAL DEVICES ON PREGNANCY RATES IN CROSS-BRED ZEBU CATTLE ARTIFICIALLY INSEMINATED AT A FIXED TIME

2006 ◽  
Vol 18 (2) ◽  
pp. 112
Author(s):  
E. Balla ◽  
D. Pincinato ◽  
D. Maraña ◽  
L. C. Peres ◽  
L. F. K. Borges ◽  
...  
Keyword(s):  
Body Condition Score ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Zebu Cattle ◽  
Duration Of Treatment ◽  
Treatment Groups ◽  
Condition Score ◽  
To Receive ◽  
Zebu Cows

Three experiments were designed to evaluate the effect of the duration of treatment with progesterone (P4) vaginal devices (1 g of P4, Triu-B; Biog�nesis, Buenos Aires, Argentina) on pregnancy rates in crossbred zebu cattle artificially inseminated at a fixed time (FTAI). In Exp. 1, 371 non-lactating multiparous crossbred zebu cows with a body condition score (BCS) between 2.0 and 3.0 out of 5 were randomly allocated to one of nine treatment groups in a 3 � 3 factorial design. On Day 0, all cows received 2 mg of estradiol benzoate (EB, Bioestrogen; Biog�nesis) i.m. and were divided into groups to receive a new Triu-B device, a once-previously-used Triu-B (2nd-use), or a Triu-B that was previously used twice (3rd-use) and in which three silicone rings (2 cm in length) impregnated with 100 mg P4 each were threaded through the wings of the device. Triu-B devices are currently approved for re-use up to three times. Cows were further subdivided to have their Triu-B devices removed on Days 7, 8, or 9. PGF (150 �g D(+)cloprostenol, Enzaprost-DC; Biog�nesis) was administered i.m. at the time of Triu-B removal, followed by 1 mg EB 24 h later; all cows were FTAI 52 to 56 h after Triu-B removal. In Exp. 2, 417 crossbred zebu heifers, 20 to 26 months of age and BCS between 2.5 and 3.5, were treated similarly to the cows in Exp. 1, except that only new or 3rd-use Triu-B were used. In Exp. 3, 836 crossbred zebu heifers, similar to those used in Exp. 2, were also treated similarly to the cows in Exp. 1, but in this case, Triu-B devices were inserted for 8, 9, or 10 days. Pregnancy rates were determined by ultrasonography 50 to 60 days after FTAI and were analyzed by logistic regression. In Exp. 1, there were no significant effects of duration of treatment [7 days: 69/137 (50.4%), 8 days: 68/139 (48.9%), or 9 days: 41/95 (43.2%); P = 0.28], or type of Triu-B used (P = 0.91; new Triu-B: 47.7%, 2nd-use: 48.9%, or 3rd-use: 47.2%). In Exp. 2, there were no significant effects of duration of treatment [7 days: 76/139 (54.7%), 8 days: 63/143 (44.1%), or 9 days: 73/135 (54.1%); P = 0.98] or type of Triu-B used (new Triu-B: 48.6% and 3rd-use Triu-B: 53.2%; P = 0.33). In Exp. 3, there was an interaction between duration of treatment and pregnancy rates (P < 0.05). Lower pregnancy rates were obtained in 9- and 10-day treatments than in 8-day treatments, but only when previously used Triu-B devices were used. Pregnancy rates were: new Triu-B for 8 days: 42/89 (47.2%), 9 days: 37/90 (41.1%), and 10 days: 41/91 (45.1%); 2nd-use Triu-B for 8 days: 51/103 (49.5%), 9 days: 39/104 (37.5%), and 10 days: 39/109 (35.8%); 3rd-use Triu-B for 8 days: 52/90 (57.4%), 9 days: 31/90 (34.4%), and 10 days: 25/70 (35.7%); P < 0.01. Results demonstrate that treatment of crossbred zebu cattle with P4 devices for 7 to 10 days results in comparable pregnancy rates when new Triu-B devices are used. However, pregnancy rates decreased when previously used Triu-B devices were inserted for more than 8 days.

8 COMBINATION OF OESTRUS DETECTION AND FIXED-TIME ARTIFICIAL INSEMINATION IN BEEF HEIFERS FOLLOWING A SHORTENED OESTRADIOL-BASED PROTOCOL THAT PROVIDES FOR A LENGTHENED PROESTRUS

2015 ◽  
Vol 27 (1) ◽  
pp. 96 ◽  
Author(s):  
J. J. de la Mata ◽  
M. Ré ◽  
G. A. Bó
Keyword(s):  
Pregnancy Rate ◽  
Body Condition Score ◽  
Fixed Time ◽  
Beef Cows ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Group V ◽  
Releasing Hormone ◽  
Treatment Groups ◽  
Condition Score

Studies have shown that gonadotropin-releasing hormone-based protocols that reduce the period of progestin insertion and prolong the period from progestin removal to gonadotropin-releasing hormone and fixed-time AI (FTAI; named 5-day Co-Synch) results in similar or higher pregnancy rates than the conventional 7-day Co-Synch protocol in beef cows and heifers (Bridges et al. 2008 Theriogenology 69, 843–851). Similar findings have been reported following the use of an oestradiol-based protocol that also provides for a longer period of proestrus (named J-Synch; de la Mata and Bó 2012 Taurus 55, 17–23). An experiment was designed to compare the J-Synch protocol for synchronization of ovulation that allows for a prolonged proestrus with a conventional 7-day oestradiol-based protocol for FTAI in heifers. Cycling 18-month old Angus and Hereford heifers (n = 208) with a body condition score of 6 to 7 (scale of 1 to 9) were randomly allocated to 1 of 2 treatment groups. Heifers in the 7-day EB group (n = 105) received a progesterone (P4) device (DIB 0.5 g of P4, Syntex SA, Buenos Aires, Argentina) and 2 mg of oestradiol benzoate (EB, Syntex SA) on Day 0 and 500 μg of cloprostenol (PGF; Ciclase DL, Syntex SA) and 0.5 mg oestradiol cypionate (Cipiosyn, Syntex SA) on the day of DIB removal (Day 7). Heifers were also tail painted at the time of DIB removal and observed for signs of oestrus (i.e. tail paint rubbed off). Those with the tail paint rubbed off by 36 h after DIB removal were inseminated 12 h later, whereas those not showing oestrus by 36 h were FTAI at 54 h. Heifers in the J-Synch group (n = 103) received DIB and 2 mg of EB on Day 0 and PGF on the day of DIB removal (Day 6). Heifers in this group were also tail painted at DIB removal, and those with their tail paint rubbed off by 48 h were inseminated 12 h later; those not showing oestrus by 60 h received 100 μg of gonadorelin acetate (gonadotropin-releasing hormone, Gonasyn gdr, Syntex SA) and were FTAI at 72 h after DIB removal. Pregnancy was diagnosed by ultrasonography at 55 days after FTAI (Honda 101V, 5.0-MHz transducer). Data were analysed by logistic regression. Oestrus detection rate and pregnancy rate to FTAI did not differ (P > 0.1) between groups (38.8%, 40/103 and 60.3%, 38/ 63 for heifers in the J-Synch group v. 28.5%, 30/105 and 45.3%, 34/75 for those in the 7-day EB group). However, pregnancy rates to observed oestrus tended (P < 0.09) to be higher and the overall pregnancy rate was significantly higher (P < 0.01) in heifers in the J-Synch group (80.0%, 32/40 and 67.9%, 70 /103) compared with those in 7-day EB group (50%, 15/30 and 46.6%, 49/105). Furthermore, heifers within the J-Synch group that had their tail paint rubbed off by 48 h after DIB removal and were AI 12 h later (i.e. 60 h) had higher (P < 0.05) pregnancy rate than those in the same group that were FTAI. In conclusion, reducing the time of progestin device insertion and lengthening the proestrus period, as in the J-Synch protocol, results in higher pregnancy rates than with the conventional oestradiol-based protocol. Furthermore, the combination of oestrus detection and FTAI would appear to improve the pregnancy outcome even more.

7 INFLUENCE OF ESTRUS EXPRESSION AND TREATMENT WITH GnRH ON PREGNANCY RATES IN BEEF CATTLE SYNCHRONIZED WITH PROGESTERONE DEVICES AND ESTRADIOL AND INSEMINATED AT A FIXED-TIME

2017 ◽  
Vol 29 (1) ◽  
pp. 111 ◽  
Author(s):  
G. A. Bó ◽  
A. Cedeño ◽  
A. Tribulo ◽  
S. Andrada ◽  
R. Tribulo ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Beef Cattle ◽  
Body Condition Score ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Device Removal ◽  
Oestradiol Benzoate ◽  
Condition Score ◽  
To Receive

We have previously shown that expression of oestrus significantly influences the time of ovulation and pregnancy rates to timed-AI (P/TAI) in beef cattle synchronized with progesterone devices and oestradiol (Bó et al. 2016 Theriogenology 86, 388–396). Furthermore, delaying TAI from 48 h to 54–58 h after device removal improved P/TAI of those animals not showing oestrus by 48 h. The objective of the present study was to determine whether the administration of GnRH to those animals not showing oestrus by 48 h after device removal had an impact on P/TAI. Non-lactating and suckled beef cows and heifers (Bonsmara, Brangus, and Braford; n = 868), with a corpus luteum (CL) or a follicle ≥8 mm in diameter detected by ultrasonography (Mindray DP 30 Vet, 7.5 MHz, China) and body condition score 2 to 4 (1 to 5 scale) were synchronized in 3 replicates. On Day 0, animals received a progesterone device (DIB 0.5 g, Zoetis, Argentina) and 2 mg of oestradiol benzoate (Von Franken, Argentina). On Day 8, DIB were removed and cows received 0.150 mg of D+cloprostenol (Río de Janeiro, Argentina) plus 0.5 mg oestradiol cypionate (Cipiosyn, Zoetis). In addition, all cows were tail-painted on the sacrococcygeal area (CeloTest, Biotay, Argentina) at DIB removal and were observed to determine the expression of oestrus, according to the percentage of paint loss (PL) 48 h later. The animals that showed oestrus (PL > 30%) were recorded and TAI at that time while those with PL ≤ 30% (not in oestrus) were randomly allocated to receive 100 μg of gonadorelin (GnRH; Gonasyn, Zoetis) or no treatment and TAI between 54 to 58 h after DIB removal. Pregnancy was diagnosed by ultrasonography at 45 days after TAI, and data were analysed by logistic regression. There were no significant differences among replicates, inseminators, semen source or animal class (dry cows, suckled cows or heifers; P > 0.11). However, animals showing oestrus by 48 h after DIB removal had higher P/TAI (371/666; 55.7; P < 0.04) than those that did not show oestrus (96/202; 47.5%). Within animals not showing oestrus at 48 h, those that were in oestrus by the TAI at 54 to 58 h had higher P/TAI (71/124, 57.3%; P < 0.01) than those that did not show oestrus within that period (27/78; 34.6%). In addition, P/TAI was higher (P < 0.01) in animals that received GnRH (66/113; 58.4%) than in those that did not receive GnRH (30/89; 33.7%). In conclusion, the expression of oestrus significantly affected P/TAI in beef cattle synchronized with progesterone devices and oestradiol. Furthermore, treatment of animals not showing oestrus by 48 h after DIB removal with GnRH resulted in improved P/TAI performed 6 to 10 h later.

scholarly journals 166 EFFECT OF TREATMENT WITH hCG OR GnRH AT THE TIME OF EMBRYO TRANSFER ON PREGNANCY RATES IN COWS SYNCHRONIZED WITH PROGESTERONE VAGINAL DEVICES, ESTRADIOL BENZOATE, AND eCG

2005 ◽  
Vol 17 (2) ◽  
pp. 234 ◽  
Author(s):  
R. Tribulo ◽  
E. Balla ◽  
L. Cutaia ◽  
G.A. Bo ◽  
P.S. Baruselli ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Bos Taurus ◽  
Body Condition Score ◽  
Bos Indicus ◽  
Beef Cows ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Condition Score ◽  
Pregnancy Status ◽  
To Receive

Although several studies have investigated the relationship between circulating progesterone and pregnancy rates in cattle, the beneficial effect of treatments that increase progesterone concentrations, by insertion of a progesterone (P4) releasing device or induction of an accessory CL with hCG, GnRH, or LH treatment, has resulted in inconsistent effects on pregnancy rates in embryo recipients. An experiment was designed to evaluate the effect of hCG or GnRH treatment, given at the time of embryo transfer without estrus detection, on pregnancy rates in recipients treated with intrauterine P4-releasing devices, estradiol benzoate (EB), and eCG. The experiment was performed in two replicates; non-lactating Bos taurus × Bos indicus crossbred beef cows with a body condition score between 2.5 to 3.5 (1-to-5 scale) were used (replicate 1, n = 180; replicate 2, n = 140). All cows received 1 g of P4 via a P4-releasing device (DIB, Syntex, Argentina) and 2 mg EB i.m. (Syntex) on Day 0, and 400 IU of eCG i.m. (Novormon 5000, Syntex) plus 150 μg d(+)cloprostenol i.m. (Ciclase, Syntex) on Day 5. DIBs were removed on Day 8 and all cows received 1 mg EB i.m. on Day 9. Recipients were not observed for signs of estrus, and those >1 CL, or a single CL with an area >256 mm2, received 195 Grade 1 and 46 Grade 2 frozen/thawed “direct transfer” embryos on Day 17. At the time of embryo transfer, recipients were randomly allocated to 1 of 3 treatment groups to receive 1500 IU hCG (Ovusyn, Syntex), 50 μg Lecirelina (GnRH, Gonasyn, Syntex), or no treatment (control) at that time. Ovarian ultrasonography was performed on Day 0 to determine ovarian status (only cows with a CL or a follicle >10 mm and uterine tone were used), on Day 17 to measure CL area, and 40 days after embryo transfer to determine pregnancy status. Data were analyzed by logistic regression and the effects of replication, technician, treatment, and embryo quality were considered in the model. From the 320 recipients treated with a DIB plus EB and eCG, 241 (75.3%) were selected to receive an embryo. Nine (3.7%) and 1 (0.4%) of the selected recipients had 2 and 3 CL, respectively. Pregnancy rates did not differ between replicates (replicate 1: 80/140, 57.1%; and replicate 2: 57/101, 56.4%; P = 0.84), technicians (technician 1: 65/118, 55.1%; and technician 2: 72/123, 58.5%; P = 0.64), or treatments (hCG: 43/80, 53.8%; GnRH: 45/83, 54.2%; and control: 49/78, 62.8% P = 0.99). However, pregnancy rates were higher (P = 0.001) in recipients receiving Grade 1 embryos (121/195, 62.1%) than in those receiving Grade 2 embryos (16/46, 34.8%). GnRH or hCG treatment at the time of embryo transfer did not increase pregnancy rates in recipients synchronized with P4 releasing devices, EB, and eCG. Research was supported by Syntex S.A., Estancia El Mangrullo S.A., and Agencia Cordoba Ciencia S.E.

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