scholarly journals Artificial induction of lactation in cattle

2010 ◽  
Vol 39 (10) ◽  
pp. 2268-2272 ◽  
Author(s):  
Priscila Ribeiro Corradi Freitas ◽  
Sandra Gesteira Coelho ◽  
Euler Rabelo ◽  
Ângela Maria Quintão Lana ◽  
Maria Alexandra Torres Artunduaga ◽  
...  
Keyword(s):  
Prostaglandin F2α ◽  
Estradiol Benzoate ◽  
Milk Composition ◽  
Regression Analyses ◽  
Dry Period ◽  
Recombinant Bovine Somatotropin ◽  
Artificial Induction ◽  
Group 2 ◽  
Scheme Evaluation ◽  
Group 1

Forty Holstein cows, with previous reproductive problems, empty, at second or more lactations, with an average milk production of 9,200 kg in the previous lactation and a dry period over than 50 days were distruibuted in two groups to evaluate two protocols of milking induction. It was given to group 1, on days one, eight and 21 recombinant bovine somatotropin-bSTr (500 mg); from day two to eight, estradiol cypionate (0.075 mg/kg BW) and medroxi progesterone acetate (0.25 mg/kg BW); from days nine to 15, estradiol cypionate (0.037 mg/kg BW); on day 19, prostaglandin F2α (0.530 mg) and from days 19 to 21, isoflupredone acetate (0.05 mg/kg BW). Group two was given, on days one, eight and 21, bSTr (500 mg), from days 2 to 15, estradiol benzoate (0.071 mg/kg BW), from days two to eight, acetate of medroxi progesterone (0.25 mg/kg BW), day 19, prostaglandin F2α(0.530 mg) and from days 19 to 21 isoflupredone acetate, (0.05 mg/kg BW). Teats and udders of all cows were massaged for five minutes from day 17 to 21. Milking were carried out from the 22nd day of induction. After beginning of lactation, both groups were given bsTr (500 mg) every 14 days. It was used a complete random design with 20 replicates per treatment and a split-plot scheme. Evaluation of the protocols was carried out by using analyses of variance using Fisher´s test at 5% and production of milking per day using regression analyses. Milking was successfully induced in 85% of the animals. Animals from group 2 showed production mean 21.9 ± 12.9 kg of milk/day which was higher than group 1 mean 18.9 ± 11.5 kg of milk/day. There was no difference for milk composition in either groups. Twenty-nine cows were inseminated and 41.1% became pregnant.

Interactions of oxytocin, potassium, and calcium in the rat uterus

1961 ◽  
Vol 201 (5) ◽  
pp. 931-934 ◽  
Author(s):  
Elwin Berger ◽  
Jean M. Marshall
Keyword(s):  
Surrounding Medium ◽  
Estradiol Benzoate ◽  
Stimulatory Action ◽  
White Rats ◽  
Tenfold Increase ◽  
Group 3 ◽  
Group 2 ◽  
K Concentration ◽  
Group 1 ◽  
External K

Ovariectomized white rats were treated as follows: group 1, 70 µg estradiol benzoate every other day for 9 days; group 2, 3.1 mg aqueous progesterone daily for 4 days then 6.2 mg daily for 5 days; group 3, untreated controls. Spontaneous muscle contractions were recorded isometrically from isolated uterine horns. Uteri from the estrogen-treated animals were the most sensitive to the stimulatory action of oxytocin (5 mu/ml). The action of oxytocin remained essentially unchanged in the presence of a tenfold increase in external K concentration in both the estrogen-treated and progesterone-treated muscles. A reduction in the Ca concentration of the surrounding medium markedly reduced the effectiveness of oxytocin. This decline in oxytocin potency was most pronounced in the estrogen-treated uteri.

Effects of progesterone withdrawal on uterine secretion of prostaglandin F2α in response to oxytocin in ewes

1997 ◽  
Vol 9 (2) ◽  
pp. 255 ◽  
Author(s):  
M. A. Kaminski ◽  
S. H. Hayes ◽  
W. J. Silvia
Keyword(s):  
Venous Blood ◽  
Prostaglandin F2α ◽  
Inhibitory Effect ◽  
Treatment Groups ◽  
Group 4 ◽  
Sham Surgery ◽  
Group 3 ◽  
Group 2 ◽  
Ovine Uterus ◽  
Group 1

Two experiments were conducted to determine if withdrawal of progesterone during the luteal phase of the oestrous cycle affected the ability of the ovine uterus to secrete prostaglandin F2α(PGF2α ) in response to oxytocin. In Experiment 1, 18 ewes were ovariectomized on Day 9 and Day 12 after oestrus. Ewes were subdivided into three treatment groups (n= 6 per group): Group-1 ewes underwent sham surgery; Group-2 ewes received oestradiol (OVX + O); and Group-3 ewes received oestradiol + progesterone (OVX + O,P). Oxytocin was administered to each ewe on Days 10, 13 and 15 after oestrus. Concentrations of 13,14-dihydro-15-keto-PGF2α (PGFM) were determined in samples of jugular venous blood for 2 h after oxytocin challenge. The magnitude of the PGFM response 24 h after ovariectomy was greater (P < 0·1) in ewes from which progesterone had been withdrawn (OVX + O) than in ewes in which progesterone was maintained (intact controls and OVX + O,P). Therefore, progesterone appears to exert an inhibitory effect on uterine secretory responsiveness to oxytocin which is removed by progesterone withdrawal. In Experiment 2, ewes were ovariectomized on Day 11 and assigned to 1 of 4 treatment groups (n = 6 per group): Group 1, no steroid replacement (OVX); Group 2, oestradiol replacement (OVX + O); Group 3, progesterone replacement (OVX + P); or Group 4, progesterone+oestradiol replacement (OVX + O,P). Ewes received oxytocin on Day 12 and Day 15. On Day 12, uterine secretory responsiveness to oxytocin was greatest in ewes in the OVX + O group (P < 0 · 1). Responsiveness was low in ewes in the OVX group, as it was in ewes in both groups that received progesterone replacement. Therefore, the increase in uterine secretory responsiveness to oxytocin following progesterone withdrawal is dependent on oestradiol replacement.

404 SUPEROVULATORY RESPONSE IN BEEF DONORS TREATED DURING THE FIRST FOLLICULAR WAVE OR FOUR DAYS AFTER PROGESTERONE AND ESTRADIOL ADMINISTRATION

2010 ◽  
Vol 22 (1) ◽  
pp. 358 ◽  
Author(s):  
D. Carballo Guerrero ◽  
A. Tríbulo ◽  
R. Tríbulo ◽  
H. Tríbulo ◽  
G. A. Bó
Keyword(s):  
Estrous Cycle ◽  
Animal Health ◽  
Estradiol Benzoate ◽  
Control Group ◽  
Wave Groups ◽  
Follicular Wave ◽  
Estrus Detection ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Although we have previously shown that ovarian superstimulation during the first follicular wave resulted in a successful response (Carballo Guerrero D et al. 2009 Reprod. Fertil. 21, 242), the current protocol needs to be optimized in order to be used in the field. Therefore, an experiment was designed to simplify this treatment and to compare it with the traditional superstimulation protocol using progesterone and estradiol. Simmental cows (n = 14) were subjected to 3 superstimulation treatments (2 first wave groups and 1 control group) in a crossover design (i.e. all cows received the 3 treatments and all treatments were represented on each collection day). Cows in Group 1 received a progesterone-releasing device (Cue-Mate®, Bioniche Animal Health, Belleville, Ontario, Canada) along with 0.150 mg of D + cloprostenol (PGF; Bioprost-D®, Biotay, Buenos Aires, Argentina) at random stages of the estrous cycle. A second PGF was injected 5 days after Cue-Mate® insertion, followed by GnRH (0.050 mg of lecirelin; Biosin-OV®, Biotay) 36 h later (i.e. 7 days after Cue-Mate® insertion). Based on previous studies, ovulation was expected to occur 30 to 36 h later. Therefore, superstimulation treatments were initiated 36 h after GnRH (Day 0), with a total dose of 400 mg NIH-FSH-P1 of Folltropin®-V (Bioniche Animal Health) in twice-daily decreasing doses over 4 days. Prostaglandin was administered with the last 2 Folltropin®-V injections and Cue-Mate® devices were removed with the last Folltropin®-V injection. Cows received 12.5 mg of porcine LH (Lutropin®-V, Bioniche Animal Health) 24 h after Cue-Mate® removal and were AI 12 and 24 h later. Ova/embryos were collected 7 days after porcine LH and evaluated following IETS recommendations. Cows in Group 2 were treated similarly to those in the Group 1, except they did not receive the second PGF injection 5 days after Cue-Mate® insertion (thus eliminating the need to handle animals on that day). Finally, cows in Group 3 [estradiol benzoate (EB)+P4 control group] received a Cue-Mate® plus 2.5 mg of EB (Bioestradiol®, Biotay) and 50 mg of progesterone (P4; Lab., Rio de Janeiro, Argentina) at random stages of their estrous cycle. Superstimulation treatments were initiated 4 days later (Day 0) following the same protocol used in Group 1. Data were transformed to square root and analyzed by ANOVA. Mean (± SEM) numbers of ova/embryos collected, fertilized ova, and transferable embryos did not differ among groups (12.9 ± 2.0, 9.8 ± 1.7, and 6.6 ± 1.2; 11.5 ± 1.7, 9.3 ± 1.5, and 7.7 ± 1.6; and 14.5 ± 2.8, 9.4 ± 2.3, and 6.8 ± 1.7 for Groups 1, 2, and 3, respectively). In conclusion, data demonstrated that superstimulation during the first follicular wave can be successfully used in groups of randomly cycling donors without the need for estrus detection or estradiol to synchronize follicular wave emergence. The protocol is easy to follow and embryo production is comparable to that of the estradiol and progesterone protocol.

351 A COMPARISON OF 2 APPROACHES FOR THE USE OF GnRH TO SYNCHRONIZE FOLLICLE WAVE EMERGENCE FOR SUPEROVULATION

2015 ◽  
Vol 27 (1) ◽  
pp. 263 ◽  
Author(s):  
R. H. Hinshaw ◽  
M. L. Switzer ◽  
R. J. Mapletoft ◽  
G. A. Bó
Keyword(s):  
Mixed Models ◽  
Animal Health ◽  
Treatment Protocol ◽  
Prostaglandin F2α ◽  
Random Variable ◽  
Crossover Design ◽  
Dominant Follicle ◽  
Follicular Wave ◽  
Group 2 ◽  
Group 1

Although oestradiol has been used successfully to synchronize follicle wave emergence for superovulation, it cannot be used in many countries. Attention has turned to alternatives, including the use of GnRH to induce ovulation of a dominant follicle, which will be followed by emergence of a new follicular wave in 1 to 2 days. However, GnRH synchronizes follicular wave emergence only when it induces ovulation and administration of GnRH at random stages of the oestrous cycle results in ovulation in less than 60% of animals. The objective of the study was to compare superovulatory response and ova/embryo production following synchronization of follicle wave emergence for superovulation with GnRH administered 2 days after insertion of a progestin device, with a protocol in which GnRH is administered 7 days after administration of prostaglandin F2α and a progestin device. Beef donors of various breeds were placed at random into 1 of 2 groups and superstimulated by replicate so that one cow in each group had ova/embryos collected on the same day. Sixty-six superstimulations were performed in this study; 26 were performed in 13 donors that were superstimulated twice in a crossover design, and 40 donors were superstimulated once (i.e. 20 donors in each treatment group). Cows in group 1 received CIDR devices (Zoetis Animal Health, USA) on Day –2 and 100 μg of GnRH (Cystorelin, Merial USA) on Day 0; FSH treatments were initiated on Day 2 with 288 mg of Folltropin-V (Vetoquinol, Canada) given in twice-daily decreasing doses for 4 days. Prostaglandin F2α (PGF; 35 mg dinoprost, Lutalyse, Zoetis) was given with the last 2 injections of Folltropin-V and CIDR were removed with the last Folltropin-V administration (i.e. Day 6). Donors received a second GnRH at the onset of oestrus and were AI 8 and 20 h later. Donors that were still in standing oestrus at the second AI were AI again at 30 h. Ova/embryo collections were done on Day 14 and embryos were classified according to the IETS manual. Cows in group 2 received an injection of PGF and a CIDR on Day –7 and 100 μg of GnRH on Day 0; FSH treatments were initiated on Day 2 and the remainder of the treatment protocol was as in group 1. Data (total ova/embryos collected and transferable embryos) were analysed by ANOVA for mixed models, using treatment as a fixed variable and cow (i.d.) as a random variable. The group 1 cows produced a mean (± s.e.m.) of 18.6 ± 1.9 total ova/embryos of which 12.7 ± 1.5 were of transferable quality (7.2 ± 1.3 grade 1). Cows in group 2 produced a mean (± s.e.m.) of 19.5 ± 1.7 total ova/embryos, of which 14.8 ± 1.5 were of transferable quality (8.9 ± 1.2 grade 1). Although 2 more transferable embryos were obtained in group 2, differences were not significant (P > 0.3). At the same time as this experiment was done, 214 other cows were superstimulated in this practice, yielding an average of 7.9 transferable embryos per donor. Results suggest that both approaches are efficacious for the superstimulation of beef cows.Special thanks to Vetoquinol/Bioniche Animal Health, USA for support.

121 Comparing Two Superstimulation Protocols Prior to Ovum Pick-Up in Dromedary Camel

2018 ◽  
Vol 30 (1) ◽  
pp. 200
Author(s):  
T. Ararooti ◽  
A. Niasari-Naslaji ◽  
K. Razavi
Keyword(s):  
Single Dose ◽  
Prostaglandin F2α ◽  
Gonadotropin Releasing Hormone ◽  
Dromedary Camel ◽  
Gnrh Analogue ◽  
Follicular Waves ◽  
Follicle Diameter ◽  
Group 2 ◽  
Good Number ◽  
Group 1

The objective of this study was to investigate different superstimulation protocol before oum pick-up (OPU) to increase the number of follicles suitable for puncture in dromedary camel. Follicular waves were synchronized using two intramuscular administrations of gonadotropin-releasing hormone (GnRH) analogue (Alarelin, 25 µg, Vetaroline®, Aburaihan, Iran) 12 to 15 days apart. Two days after the second GnRH (Day 0 of experiment), donors were assigned into 2 groups (n = 6 in each group) receiving different amounts of eCG (Pregnecol®, Bioniche, Canada; intramuscular) and FSH (Folltropin-V®, Bioniche, Canada; intramuscular). Groups 1 and 2 received the respective amounts of eCG (3000 and 2000 IU) and FSH (200 and 160 mg). The eCG was administered as a single dose at the start of superstimulation and FSH was delivered twice daily in decreasing doses (group 1: 40, 30, 20, 10 mg; group 2: 30, 20, 20, 10 mg) between Days 0 and 3. On Day 4 of superstimulation, camel received 2 doses of prostaglandin F2α analogue (25 mg of dinoprost tromethamine; Lutalyse®, Pfizer, Belgium; intramuscular), 12 h apart and were examined by ultrasonography in the morning to record ovarian follicles (≥4 mm in diameter). Data were analysed using GLM procedure followed by Tukey in SAS (SAS Institute Inc., Cary, NC, USA). Data were presented as mean ± SEM. On Day 4 of superstimulation, the average follicle diameter was similar in group 1 (6.4 ± 0.16 mm) and group 2 (7.4 ± 0.33 mm; P > 0.05). The total number of follicles were different between group 1 (15.5 ± 1.75) and group 2 (4.7 ± 0.71; P < 0.001). Total number of follicles ≤6 was significantly greater in group 1 (6.2 ± 0.95) than in group 2 (1.2 ± 0.60; P < 0.05). Total number of follicles >6 mm in group 1 (9.3 ± 1.20) was greater than in group 2 (3.5 ± 0.76; P < 0.01). In conclusion, superstimulation with eCG (3000 IU) and FSH (200 mg) could provide a relatively good number of follicles for aspiration in OPU program of dromedary camel.

scholarly journals PSII-2 The impact of essential oil supplementation on sow milk composition and fecal dry matter

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 229-229
Author(s):  
Shannon L Dierking ◽  
H J Monegue ◽  
Merlin D Lindemann
Keyword(s):  
Dry Matter ◽  
Milk Composition ◽  
Late Gestation ◽  
Gross Energy ◽  
Group 3 ◽  
Group 2 ◽  
The Individual ◽  
Dietary Treatments ◽  
The Impact ◽  
Group 1

Abstract The transition from gestation to lactation greatly impacts the sow body. The expulsion of piglets, placenta, and fluids can result in dehydration and consequently constipation post-farrowing. The objective of this study was to determine the effects of an EO product (tradename Absorbezz) on sow fecal dry matter and milk composition. A total of 101 late-gestation sows from three farrowing groups (Group 1: 110 ± 3 d GEST, 263 ± 28 kg initial BW, Group 2: 109 ± 1 d GEST, 259 ± 26 kg initial BW, Group 3: 73 ± 5 d GEST, 238 ± 30 kg initial BW) were allotted to one of two treatments based on parity and BW in each group (Groups 1 and 2: CON: No EO, TRT: 10 mL/d of EO top-dressed; Group 3 received the EO as part of their diet, with a range dependent on the individual sow’s daily feed intake). Sows remained on their respective dietary treatments throughout the remainder of gestation and lactation. Samples were collected from each group (feces; d 110 of gestation, d 4 to 6 and day 14 to 17 of lactation; milk (Group 2 and 3); d 14 to 17). Analysis of variance was performed using PROC GLM of SAS. The TRT group did not experience any differences in the components of fat, protein, and total solids (P > 0.10), there was an increase in lactose (5.97 vs 5.84, P = 0.04), but a decrease in solids non-fat (10.91 vs. 11.00, P = 0.07), and gross energy compared to those of the CON group (4.29 mJ/kg vs. 4.45 mJ/kg, P = 0.08). Fecal DM was not affected at any collection time (P > 0.10). Overall, the addition of EO did not affect fecal DM, but did influence several milk components.

scholarly journals Recombinant bovine somatotropin in the synchronization of ovulation in crossbred dairy cows (Bos taurus indicus × Bos taurus taurus)

2020 ◽  
Vol 13 (4) ◽  
pp. 746-750
Author(s):  
Fabrício Albani Oliveira ◽  
Ítalo Câmara de Almeida ◽  
Larissa Marchiori Sena ◽  
Jurandy Mauro Penitente-Filho ◽  
Ciro Alexandre Alves Torres
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Bos Taurus ◽  
Prostaglandin F2α ◽  
Estradiol Benzoate ◽  
Bovine Somatotropin ◽  
Recombinant Bovine Somatotropin ◽  
Equine Chorionic Gonadotropin ◽  
The Moment ◽  
Follicular Dynamics

Aim: The aim of this study was to evaluate the effects of the administration of recombinant bovine somatotropin (rbST) at the moment of implementation of the timed artificial insemination protocol, on follicular dynamics and pregnancy rate in crossbred cows. Materials and Methods: A total of 346 cows were used in two experiments with a factorial 2×2 design. The cycling cows (Tcycling) and the anestrous cows (Tanestrous) were considered as factor 1 and the administration of rbST (TrbST) or not (Tcontrol) as factor 2. The experimental protocol: (1) Tcontrol – day 0 (D0), insertion of a progesterone-release intravaginal device (PRID) plus 2 mg of estradiol benzoate (EB); D8, PRID removal, plus 0.150 mg of prostaglandin F2α, and 400 IU of equine chorionic gonadotropin; D9, 1 mg of EB; and with artificial insemination at day 10; (2) TrbST – similar to Tcontrol plus 500 mg of rbST on D0. In experiment I, ultrasound examinations were performed in all treatments. In experiment II, the cows' pregnancy rate was evaluated. Data were analyzed with 5% probability. Results: There was no effect of the protocols on cows cyclicity or follicular growth rate (p>0.05). There was no interaction of the effects, administration of rbST, and the cyclicity of cows on the pregnancy rate. The total pregnancy rate observed was 49.0%. The pregnancy rate in cows receiving rbST was lower for anestrous compared with cycling cows (p<0.05). Conclusion: The administration of rbST did not alter the patterns of follicular dynamics nor the ovulation rate. However, cows in anestrous that received rbST had lower pregnancy rates than cycling cows.

scholarly journals Rational Decision On the Use of Antibiotics During the Dry Period in Dairy Cows

2019 ◽  
Author(s):  
Luis O. Lopes ◽  
Anna M. C. Lima
Keyword(s):  
Dairy Cows ◽  
Somatic Cell ◽  
Statistical Difference ◽  
Coagulase Negative Staphylococcus ◽  
Dry Period ◽  
Microbiological Culture ◽  
Group 3 ◽  
Group 2 ◽  
Sealant Group ◽  
Group 1

ABSTRACTThe aim of this study was to evaluate the use of antibiotics in cows during the dry period. The survey was performed on 148 teats during the dry period, with sample collection in the period D-70 (70 days before delivery) and D14 (14 days after delivery). The milk samples were collected for the Strip Cup Test (SCT), California Mastitis Test (CMT), Microbiological Culture, Somatic Cell Count (SCC), Somatic Cell Score (SCS) and Hyperkeratosis (HK). The groups in which there were no microorganisms grow were divided into two groups, in the first group only the internal sealant in the teat was used (Group 1) and there was another group with the intramammary antibiotic use associated with the internal sealant (Group 2). Teats which were considered positive, with microbiological growth, were treated with the intramammary antibiotic associated with the internal sealant (Group 3). In the comparison of the results of the CMT test between D-70 and D14, a statistical difference was observed in Groups 2 and 3. Group 3, which comprises the positive teats in D-70 presented a reduction of 83.87% and 32.26% in the CMT test between D-70 and D14. Regarding HK, group 1 and 2 had a statistical difference in relation to group 3 in D-70 and D14. As for the numbers of bacteria isolated in D-70 and D14, there was no difference comparing Group 1 and Group 2, unlike Group 3, which had a difference. Group 1 and Group 2 were all negative teats in D-70, showing that the intramammary antibiotic did not influence the outcome of D14. In group 3 there was a reduction of isolates from 62 to 15 in D14. The most prevalent microorganism was Streptococcus agalactiae with 43.37% of the total isolates, followed by Staphylococcus aureus (16.87%) and Corynebacterium spp. (13.25%) and Coagulase negative Staphylococcus (SCN) (10.84%). The selective treatment of teats in dry dairy cows has advantages over Blanket Dry Cow Therapy by reducing the indiscriminate use of antibiotics, avoiding bacterial resistance, ensuring better milk quality and greater food safety. Antibiotics should only be used for teats with subclinical mastitis, with the microbiological culture at the end of lactation performed by fourth individual mammary.

166 COMPARISON OF TWO METHODS TO SYNCHRONIZE CROSSBRED BEEF HEIFERS FOR EMBRYO TRANSFER

2010 ◽  
Vol 22 (1) ◽  
pp. 241
Author(s):  
J. B. S. Borges ◽  
D. Thedy ◽  
D. Mendes ◽  
R. Kawata
Keyword(s):  
Embryo Transfer ◽  
Body Condition Score ◽  
Test Group ◽  
Estradiol Benzoate ◽  
Ovulation Rate ◽  
Beef Heifers ◽  
Estrous Synchronization ◽  
Group 2 ◽  
Intravaginal Device ◽  
Group 1

Estrous synchronization with prostaglandin in commercial MOET programs frequently results in insufficient numbers of recipients for embryo transfer. The aim of this trial was to compare the efficiency of 2 different methods of estrous synchronization in crossbred beef heifers. A total of 235 cycling heifers (Brangus and Braford), with a mean age of 24 months (range 22-26 months), body condition score of 3.5 ± 0.1 (1-5 scale), and mean weight of 340 ± 22 kg were assigned to 2 treatment groups stratified according to body weight and genotype. In Group 1 (n = 157), heifers received 2 injections of prostaglandin [Croniben, 150 μg of D(+) cloprostenol, i.m.; Biogenesis-Bágo, Buenos Aires, Argentina] with an interval of 14 days. After the second injection, detection of estrus was monitored for 5 days. In Group 2 (n = 78), heifers received an intravaginal device of progesterone (Day 0; 0.558 g; Cronipres Mono Dose M-24, Biogenesis-Bágo) and at the same time received an i.m. injection of estradiol benzoate (2 mg; Cronibest, Biogenesis-Bágo). On Day 7, devices were removed and heifers were injected with prostaglandin. Twenty-four hours later (Day 8), 1 mg of estradiol benzoate was injected i.m. All recipients had estrus detected for 72 h after the end of treatment to determine the estrous synchronization rate. Before embryo transfer 7 days after the detected estrus, heifers were examined by transrectal ultrasonography (Chison 600Vet, 5-MHz transducer, National Ultrasound, Duluth, GA, USA) to confirm the presence of a CL and its size or an unovulated follicle on the ovaries. Those with a CL of 1.7 cm2 or greater were selected to receive a frozen-thawed embryo. The frequencies of synchronous estrus, ovulation, unovulated follicles, and use of recipients were compared by chi-square test. Group 2 had a higher estrous synchronization rate (70%) and proportion of selected recipients (51.2%) compared with Group 1 (55% and 35.6%, respectively; P < 0.05). Ovulation rate (64% v. 72%) and incidence of unovulated follicles (20.6% v. 21.8%) for Groups 1 and 2, respectively, did not differ (P > 0.05). In summary, treatment with a 0.558-g progesterone intravaginal device, plus injections of estradiol benzoate and PGF, was more efficient than 2 PGF injections alone in synchronizing estrus and increased the use of crossbred beef heifer recipients in MOET programs. The ovulation rate and incidence of unovulated follicles were similar in both methods of estrous synchronization.

312 INFLUENCE OF LARGE NONOVULATED FOLLICLES ON ESTROUS INDUCTION AFTER EMBRYO COLLECTION IN SUPEROVULATED JAPANESE BLACK COWS

2013 ◽  
Vol 25 (1) ◽  
pp. 303
Author(s):  
M. Taniguchi ◽  
E. Sasaki ◽  
T. Otoi
Keyword(s):  
Statistical Significance ◽  
Prostaglandin F2α ◽  
Visual Observation ◽  
Corpora Lutea ◽  
Serum Progesterone ◽  
Once Daily ◽  
Group 2 ◽  
Student’S T ◽  
Group 1 ◽  
Donor Cows

Rapid oestrous induction after embryo collection shortens the calving interval of donor cows and improves the efficiency of embryo production. This study aimed to evaluate whether large nonovulated follicles present at the time of embryo collection affect oestrous induction after embryo collection in Japanese Black donor cows. Superovulation treatments were initiated during mid-cycle (9–12 days after oestrus) with 20 AU of FSH (Antrin; Kyoritsu Seiyaku Corp., Tokyo, Japan) administered intramuscularly through 6 injections of decreasing doses at 12-h intervals. On the third day, the cows received 0.5 mg of prostaglandin F2α (PGF; Resipron-C, Asuka Seiyaku Corp., Tokyo, Japan) to induce regression of the corpus luteum and were artificially inseminated 60 to 72 h later. Embryos were collected 7 days after AI. All cows received 0.5 mg of PGF immediately after embryo collection and were allocated to 1 of 2 groups: cows (n = 6) with one or more large nonovulated follicles >18 mm in diameter (Group 1) and cows (n = 5) with no large follicles (Group 2). Oestrus detection was performed by visual observation conducted twice daily after embryo collection. Ovarian ultrasonographic examinations and blood collections (for serum progesterone [P4] and oestradiol [E2] measurements) were performed once daily until the next ovulation. Statistical significance was determined using Student’s t-test. There were no differences in the numbers of corpora lutea, ova/embryos, and transferable embryos or the percentages of transferable embryos between the 2 groups. The interval (mean ± SEM) from embryo collection to the appearance of the dominant follicle and to ovulation was longer (P < 0.05) in Group 1 (5.3 ± 0.7 and 11.0 ± 1.0 days, respectively) than in Group 2 (2.6 ± 0.7 and 8.2 ± 0.7 days, respectively). However, the interval from embryo collection to luteolysis (P4 <1 ng mL–1) did not differ between the 2 groups (4.0 ± 0.7 v. 3.6 ± 0.7 days). In conclusion, the presence of large nonovulated follicles at the time of embryo collection may delay oestrous induction after embryo collection.

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