12 Assessment of oocyte and embryo production in senescent beef cows

2020 ◽  
Vol 32 (2) ◽  
pp. 131
Author(s):  
R. H. Alvarez ◽  
B. M. Bayeux ◽  
Y. F. Watanabe ◽  
D. A. Joaquim ◽  
K. M. R. Duarte ◽  
...  

Fertility associated with age has been poorly documented in cattle. There is evidence that more than 50% of cows became infertile (failure to bear a calf for two successive years) at the age of 15. The causes of infertility in cows have been attributed to poor oocyte quality and/or follicle depletion. The present study aimed to compare the rates of oocyte and invitro embryo production of fertile cows older than 15 years. Sixteen Nellore cows (Bos taurus indicus) 200.3±4.9 months old were submitted to two ovum pickup series (OPU1 and OPU2) at a 2-year (2017 and 2019) interval. Before the OPU1 of each series, the cows were prepared with an IM injection of 2mg estradiol benzoate and 0.15mg prostaglandin F2α analogue and a progesterone-releasing intravaginal device (1g). After five days, the progesterone-releasing intravaginal device was withdrawn and the OPU1 was performed. The second OPU (OPU2) was performed 5 days later to aspirate only the growing follicles. The number and morphologic quality of recovered cumulus-oocyte complexes were registered. After IVM (tissue culture medium 199) and fertilization (Tyrode's solution) of cumulus-oocyte complexes, the presumptive zygotes were cultured in synthetic oviductal fluid with amino acids to assess developmental rates to blastocyst. Data were analysed by chi-squared and Wilcoxon test. The number of oocytes recovered at OPU1 was higher in 2107 than in 2019 (27.8±6.6 vs. 10.8±4.2; P<0.01), whereas in OPU2 the production of oocytes was not different (14.7±3.3 vs. 10.9±3.1). In OPU1, eight cows in 2017 and four in 2019 produced more than 20 oocytes, compared with only one cow in OPU2 of both years (P=0.02). Although there was no significant difference in the proportion of viable oocytes in OPU1 (83.6% and 87.2%) and OPU2 (85.5 and 68.0%), more viable oocytes were produced at OPU1 of 2017 (23.2±5.8) compared with OPU1 of 2019 (9.4±4.1), OPU2 of 2017 (12.6±2.7) and OPU2 of 2019 (7.4±2.4), respectively (P<0.05). There was no significant difference in the proportion of cleaved oocytes in OPU1 (74.2 and 75.1%) and OPU2 (68.9 and 79.8%). Two cows in 2017 (12.5%) and five in 2019 (31.2%) did not produce embryos in both OPUs. Cows produced more embryos (blastocysts) in OPU1 at 2017 (7.3±1.6) than 2019 (2.8±0.6; P<0.05), whereas in OPU2 there was no difference (4.1±0.8 and 3.1±0.8). In conclusion, senescent fertile cows decreases the number of oocytes and embryos as they approach 20 years of age; however, the quality of oocytes does not appear to be compromised. Financial support was provided by FAPESP (proc. 2018/07450-5).

2008 ◽  
Vol 20 (1) ◽  
pp. 89
Author(s):  
M. F. Pegorer ◽  
R. L. Ereno ◽  
C. M. Barros

Previous reports indicate that a high concentration of serum progesterone (P4) decreases LH pulse frequency (Burke et al. 1996 Anim. Reprod. Sci. 45, 13–28) and, consequently, follicular growth. This may reduce the efficiency of fixed-time artificial insemination (FTAI) protocols that utilize P4 in Bos indicus heifers (Marques et al. 2005 Acta Sci. Vet.). The objective of the present work was to evaluate the influence of different P4 concentrations on the ovulation and pregnancy rates of zebu heifers subjected to hormonal protocols for FTAI. Four hormonal protocols with different P4 concentrations were used to induce synchronization of ovulation in Nelore (Bos indicus) heifers (n = 292). Before the beginning of the treatments, the animals were subjected to ovary evaluations by ultrasonography (Aloka SSD 500, 5-MHz probe; Aloka, Tokyo, Japan) twice in an interval of 10 days. Only heifers with a corpus luteum (CL) in at least one of the ultrasonographic evaluations were utilized. At a random stage of the estrous cycle, the selected heifers received an intravaginal progesterone-releasing device containing 0.558 g of P4 [Triu�, Biogenesis, Buenos Aires, Argentina; Treatment 1 (T1); n = 76], or 1 g of P4 [Cronipress�, Biogenesis; Treatment 2 (T2); n = 70], or 0.558 g of P4 and prostaglandin F2α (PGF2α) [150 �g d-cloprostenol, IM, Croniben�, Biogenesis; Treatment 3 (T3), n = 75], or 1 g of P4 and PGF2α [Treatment 4 (T4), n = 71]. At the time of intravaginal device insertion (Day 0 = D0), all animals received 2 mg of estradiol benzoate (EB, Bioestrogen�, IM, Biogenesis), and PGF2α was administered only in animals from groups T3 and T4. Eight days later (D8), PGF2α (0.150 g d-cloprostenol) was administered to all heifers and the P4 source was removed. Twenty-four h after removal of the intravaginal device, the heifers were treated with EB (1 mg, IM), and 30 to 36 h later all animals were fixed-time inseminated (FTAI, D10), without estrus detection. In a subset of heifers from each group (T1 = 28; T2 = 34; T3 = 33; T4 = 31), ovarian ultrasonography was performed on D9 (at 8:00 A.M.) and D11 (at 14:00 P.M.) in order to determine ovulation rate after each treatment. The data were analyzed by logistic regression (GENPROC, SAS; SAS Institute, Inc., Cary, NC, USA). Ovulation rates after treatments T1, T2, T3, and T4, were, respectively, 71.4% (20/28), 76.5% (26/34), 84.9% (28/33), and 70.9% (22/31), and there was no significant difference among groups (P > 0.05). Pregnancy rates, ascertained by ultrasonography 40 days after AI, were 30.2% (23/76), 25.7% (18/70), 33.3% (25/75), and 28.2% (20/71), respectively, for T1, T2, T3, and T4, and likewise there was no significant difference among groups (P > 0.05). It is concluded that reduction of progesterone concentration in the intravaginal device (1 g v. 0.558 g) associated or not with administration of PGF2α at the beginning of treatments did not significantly influence ovulation and pregnancy rates in Nelore heifers submitted to a FTAI protocol. Additional experiments are underway to confirm or not the present results. This work was supported by FAPESP (Brazil) and BIOGENESIS (Argentina).


2013 ◽  
Vol 25 (1) ◽  
pp. 155
Author(s):  
L. D. P. Sinedino ◽  
B. T. Gerhardt ◽  
J. A. Moura ◽  
A. P. Dourado ◽  
I. L. Goulart ◽  
...  

Physiological and behavioral differences between Bos taurus and Bos indicus can influence the response to a fixed AI protocol. The objective of this study was to examine the reduction of the usual dose of 2 mg of estradiol benzoate (EB) to 1 mg at the beginning of a fixed-time AI protocol, aiming at follicular regression. In a second step, we evaluated the effect of EB on follicle development during follicular pre-deviation and dominance. The experiment was performed at Monte Verde Farm (Uberaba, MG, Brazil). Twenty-two cows (n = 10 heifers and n = 12 nonlactating cows) underwent an estrous synchronization protocol with a progesterone-releasing intravaginal device (P4; Sincrogest®, Ouro Fino Animal Health, São Paulo, Brazil) and received 1 (G1mg, n = 11) or 2 mg (G2mg, n = 11) of EB (Sincrodiol®, Ouro Fino Animal Health), on a random day (designated Day 0). Follicular dynamics was monitored once per day by ultrasonography from Day 0 to 4 with blood sample collections. In a second step, females received 2 mg of EB on Day 3 (GD3, pre-deviation, n = 4) or Day 5 (GD5, dominance, n = 4) of the estrous cycle (Day 0 was the ovulation). Following these treatments, follicular development was monitored daily for 6 days with blood sample collections. The statistical analysis was conducted using the SAS System for Windows 2 (2003; SAS Institute Inc., Cary, NC, USA). The explanatory variables included in the statistical model were the dose of EB, animal category (cows and heifers), and their interaction. The mean test was used to compare intervals from EB treatment to follicular atresia and follicular wave emergence using ANOVA. Progesterone concentrations between groups were compared using the Wilcoxon test. Independently of animal category or stage of the estrous cycle, both EB doses (1 or 2 mg) induced follicular atresia in 2.2 ± 0.9 and 2.1 ± 1.2 days (P > 0.05), respectively. Emergence of a new follicular wave was observed, from Day 0 to 4, in 64% (7/11) of females from G1mg and in 45% (5/11) from G2mg, and the interval between treatment and follicular emergence was 3.4 ± 0.8 and 3.0 ± 1.0 days (P > 0.05), respectively. Plasma progesterone concentrations of the 22 animals increased from 2.1 ± 2.0 ng mL–1 to 7.6 ± 3.0 ng mL–1 by 24 h after the device insertion (P < 0.05), reaching peak concentration (8.0 ± 3.0 ng mL–1) by 48 h after treatment beginning, decreasing to 6.4 ± 2.5 ng mL–1 by 72 h, and remaining constant up to 96 h. Estradiol benzoate injection at follicle pre-deviation (GD3) caused follicular atresia (2.0 ± 1.4 days) and emergence of a new follicular wave in 3.7 ± 0.1 days in all animals (4/4). However, EB injection during follicle dominance (GD5) did not synchronize a new follicular wave and follicles persisted during the time of monitoring. Furthermore, EB applied at dominance hastened luteolysis in 50% (2/4) of the treated animals. In conclusion, a reduced dose of EB (1 mg) at the beginning of the protocol with P4 effectively induces follicular atresia. To synchronize a wave emergence at any stage of the estrous cycle, EB must be associated with an exogenous source of progesterone.


2005 ◽  
Vol 17 (2) ◽  
pp. 234 ◽  
Author(s):  
R. Tribulo ◽  
E. Balla ◽  
L. Cutaia ◽  
G.A. Bo ◽  
P.S. Baruselli ◽  
...  

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.


2015 ◽  
Vol 98 (5) ◽  
pp. 3086-3099 ◽  
Author(s):  
J.N.S. Sales ◽  
L.T. Iguma ◽  
R.I.T.P. Batista ◽  
C.C.R. Quintão ◽  
M.A.S. Gama ◽  
...  

2020 ◽  
Vol 6 (1) ◽  
pp. 36-43
Author(s):  
Yeti Kartikasari ◽  
M. Irwan Kartili ◽  
Dwi Rochmayanti ◽  
Nindya Aprilia

Background: Stroke is a brain disease where an acute nerve function is occurred due to the cerebral vascular disorders. To establish a diagnosis the stroke, it can be identified by employing the Diffusion Weighted Imaging (DWI) sequence in the MRI examination. Artifacts still exist on the MRI image which in turn reduce the resolution when using the DWI sequence. Adding the PROPELLER data acquisition method in the DWI sequence possibly improves the quality of brain images. The purpose of this study is to know the difference on the quality of anatomical image information between the DWI sequences with PROPELLER and without PROPELLER methods, and to determine adequate anatomical image appearance that created in amongst of the two methods, specifically for the stroke disease.Methods: this research is quantitative research with experimental approach. This study was conducted using MRI 1.5 T at Bethesda Hospital Yogyakarta. Data were 16 images from 8 patients using DWI sequences using PROPELLER without PROPELLER on MRI Brain examination with stroke. The results of the image were evaluated on 7 criteria: cortex cerebri, basal ganglia, thalamus, pons, cerebellum, stroke (infarction) and artifacts using questionnaires given to 3 respondents. Data analysis was done by Wilcoxon test to know the difference of anatomical image information on DWI sequence using PROPELLER without PROPELLER and to know better anatomical image information from both sequences seen from mean rank value.Results: The results shown, there is a significant difference on the quality of anatomical image information and the artifacts between the use of DWI sequence with and without PROPELLER methods ( 0.05). Based on the mean rank results, the DWI PROPELLER sequence has a higher mean rank value 4.50 compared to the DWI sequence without PROPELLER 0.00.Conclusions: The DWI PROPELLER sequence has better image results compared to the DWI sequence without PROPELLER.


2006 ◽  
Vol 18 (2) ◽  
pp. 224
Author(s):  
G. Cancino-Arroyo ◽  
R. Ake-López ◽  
J. Herrera ◽  
F. Centurion ◽  
A. Ordoñez-León

The objective was to evaluate the effect of fat supplementation on oocyte quality and in vitro embryonic development (48 h). A total of 18 ewes, with a body condition score of 2.5 to 3 points out of 5, having had three to four lamb births, and at three to four months post-lamb birth, were distributed between an experimental oil group (OG; n = 9) that received corn oil (4% of the MS/diet) and a control group (CG; n = 9) that didn't receive oil. The two groups were maintained in confinement for 21 days (the duration of the experiment) and fed first with a concentrate diet followed by forage. The animals had access to minerals and water ad libitum. The diets were similar in energy (10.3 ± 0.05 MJ/s/d) and protein (141.75 ± 5.7 gPC/s/d) for both groups. The estrous cycle was synchronized (14 days) with intravaginal sponges (40 mg of fluorogestone acetate), inserted 7 days after the beginning of the diets. The end of the diet coincided with the retirement of the sponges. One day before sponge retirement, 75 mg prostaglandin F2α per sheep was administered, followed by ovarian stimulation with 1000 IU of pregnant mare serum gonadotropin (PMSG). Follicular diameter was determined by ventral laparotomy with the aid of a micrometer. Follicles were classified as small (2 to 2.9 mm), medium (3 to 4.9 mm), and large (>5 mm); oocytes were collected in TCM-199 medium. Oocytes were classified as excellent, good, fair, or low quality and transferred to Petri dishes in drops (50 mL) of TCM-199. Oocytes were matured and fertilized in vitro and cultured for 48 h. Oocyte quality as well as maturation, fertilization, and cleavage rates were compared by ANOVA. Ewes from the OG group presented a statistically higher proportion of oocytes with excellent quality (42%; P < 0.05) than GT ewes (26%). The proportion of good quality and fair quality oocytes was similar among groups (P > 0.05). A higher proportion of oocytes of low quality was found in the control group than in the OG group (40% vs. 18%); however, there was no significant difference (P > 0.05). Higher rates of maturation, fertilization, and early development were found in the OG compared with the CG (81.8, 60.6, and 36.4 vs. 68.6, 42.9, and 17.1, respectively); however, the differences were not significant (P > 0.05). In conclusion, the addition of 4% corn oil in the diet improved the quality of the oocytes; however, it had no significant effect on early embryonic development.


2014 ◽  
Vol 26 (1) ◽  
pp. 118 ◽  
Author(s):  
M. Re ◽  
J. J. de la Mata ◽  
G. A. Bo

Several studies, performed mainly in North America, have shown that the 5-day co-synch timed-AI (TAI) protocol results in similar or higher pregnancy rates than conventional 7-day co-synch protocols in beef cows and beef and dairy heifers. It is hypothesised that the 5-day co-synch protocol reduces the incidence of persistent follicles and provides for a longer proestrus, with increasing oestradiol concentrations due to continuous gonadotropin support for the dominant follicle (Bridges et al. 2008 Theriogenology 69, 843–851). Similar findings have been reported recently following the use of a shortened oestradiol-based protocol that also provides for a longer proestrus (named J-synch; de la Matta and Bo 2012 Taurus 55, 17–23). A study was designed to compare these 2 treatment protocols for synchronization of ovulation that allow for a prolonged proestrus with the conventional oestradiol-based protocol currently used for TAI in South America for heifers. Cycling Holstein heifers that were, on average, 17 months of age, weighting 350 to 380 kg, and with a body condition score of 2.5 to 3.5 (scale of 1 to 5), were randomly allocated to 1 of 3 treatment groups. Heifers in the 7-day estradiol benzoate (EB) group received a progesterone device (DIB 1 g of progesterone; Syntex SA, Buenos Aires, Argentina) and 2 mg EB (oestradiol benzoate, Syntex SA) on Day 0, 500 μg of cloprostenol (prostaglandin F2α; Sincronil, Proagro SA, Argentina) and DIB removal on Day 7, 1 mg of EB on Day 8, and TAI 30 h later (54 h after DIB removal). Heifers in the J-synch group received a DIB and 2 mg of EB on Day 0, PGF and DIB removal on Day 6, and 10 μg of buserelin acetate [gonadotropin-releasing hormone (GnRH); Receptal, Intervet, Millsboro, MD, USA] and TAI on Day 8 (72 h later). Heifers in the 5-day co-synch group received a DIB and GnRH on Day 0, DIB removal and prostaglandin F2α (twice, 12 h apart) on Day 5, and GnRH along with TAI on Day 8 (72 h later). Treatments were coordinated so that DIB were removed in all groups at the same time to decrease a possible time effect of follicle parameters and pregnancy rates. Two experiments were conducted; the first evaluated follicular dynamics and ovulation rates by twice daily ultrasonography (Honda 101 V, 5.0 MHz) in 20 heifers per group and the second determined pregnancy rates to TAI in 172 heifers. The mean (± standard error of the mean) interval from DIB removal to ovulation was shorter in the 7-day EB group (82.7 ± 3.1 h) than in the J-synch (103.8 ± 3.3 h) and 5-day co-synch (96.8 ± 3.3 h) groups (P = 0.01). However, the mean diameter of the dominant preovulatory follicle was smaller (P = 0.01) in the 7-day EB (12.8 ± 0.5 mm) and the J-synch (13.1 ± 0.6 mm) groups than in the 5-day co-synch group (14.9 ± 0.6 mm). Although pregnancy rates in the second experiment were numerically lower in the 7-day EB group (31/58; 53.4%) and 5-day co-synch group (30/55; 54.5%) than in the J-synch group (37/59; 62.7%), differences were not significant (P > 0.3). Preliminary results indicate that the 3 protocols evaluated result in comparable pregnancy rates to TAI in dairy heifers.


2012 ◽  
Vol 24 (1) ◽  
pp. 224 ◽  
Author(s):  
R. L. Davis ◽  
A. Arteaga ◽  
J. F. Hasler

This study examined the superovulatory responses of Bos taurus beef cows maintained in a commercial embryo transfer facility. Donors were superovulated 1 to 3 times each with either a traditional 8 injection FSH protocol (controls, n = 126) or 6 injections of FSH with the seventh or eighth FSH treatments replaced by 2 injections of eCG (treatment, n = 134). During the 5-month study, 132 donors were alternatively assigned to a control or treatment group for a single superovulation and an additional 62 animals were superovulated 2 (n = 58) or 3 times (n = 4) in a crossover design. Although 14 beef breeds were represented in the study, 87% of the cows were Angus, Red Angus, Polled Hereford, or Charolais. All donors were synchronized on Day 0 with a CIDR, 5 mg of oestradiol-17β and 100 mg of progesterone. Starting on Day 4 (p.m.), controls were injected twice daily for 4 days with descending doses of porcine FSH (Folltropin-V®, Bioniche Animal Health, Belleville, Ontario, Canada). Cows received 750 μg of cloprostenol (Estrumate®, Intervet Schering-Plough, Summit, NJ, USA) at the seventh FSH injection and the CIDR was removed at the eighth FSH injection. Based on previous experience with specific, individual animals, total FSH dose per donor ranged from 240 to 400 mg. However, 74% of treatments involved 380 mg for controls and 310 mg for treated donors that received eCG. In addition, donors that were superovulated more than once received the same FSH dose in the crossover, treatment-control design. In the treatment group, 200 IU of eCG (Pregnecol™ 6000, Bioniche Animal Health) was substituted for the seventh and eighth FSH injections. Inseminations were conducted on a timed AI basis, with one unit of semen 32 h and a second 48 h following CIDR removal. Results were analysed by ANOVA as shown in Table 1. Although more ova/embryos and unfertilized ova (UFO) were recovered in the control group, the control and treatment groups did not differ in the number of grade 1, 2, or 3 embryos or in the number of degenerate embryos. Previous superovulation studies in South America using eCG to replace the last 2 injections of FSH resulted in more total ova/embryos in Nelore cows but not heifers and in more embryos in Brangus and Sindhi cows. The mean embryo production for the control cows in this study was high and the addition of eCG in the protocol did not improve embryo production. Failure of eCG to increase the number of embryos for Bos taurus cows in this study compared with previous studies may be due to differences with Bos taurus versus Bos indicus breeds or differences in management factors between Canada and South America. The high response rate in the controls may also have contributed to the failure of any advantage of adding eCG to the treatment protocol. Table 1.Mean numbers (± SEM) of ova and embryos recovered from Bos taurus females superovulated with 2 different protocols


2008 ◽  
Vol 20 (1) ◽  
pp. 155
Author(s):  
M. Urakawa ◽  
A. Ideta ◽  
K. Hayama ◽  
K. Tsuchiya ◽  
Y. Aoyagi

Repeat-breeding Holstein cows (RBCs), i.e. cows that have undergone three or more AIs, have reduced pregnancy rates. The present study aimed to determine whether application of a combination of a PRID� (ASKA Pharmaceutical Co., Inc., Tokyo, Japan) + prostaglandin F2α (PGF2α) for estrus synchronization and AI + embryo transfer (ET) would improve pregnancy rates in RBCs. All RBCs selected showed a normal interval between the previous insemination and estrus, and were free of clinical disorders. The RBCs (n = 107) received a PRID for 9 days with a capsule containing 10 mg of estradiol benzoate, 0.5 mg IM of cloprostenol (PGF2α, Resipron�-C; ASKA, Japan) at 2 days before PRID removal. The cows were inseminated with frozen–thawed semen from a bull at 0 to 12 h after onset of estrus. Seven days after AI, single in vitro-produced embryos were transferred to the same RBCs. Pregnancy was diagnosed by palpation per rectum at e60 days post-insemination. Exp. 1 estimated the response to estrus synchronization treatment (n = 107). The factors examined were lactation number (mean � SD: 2.3 � 1.5, range: 1–6), insemination number (5.2 � 2.2, range: 3–13), and the interval from calving to next AI (275.9 � 97.6 days, range: 93–650 days). Exp. 2 compared the pregnancy rate in control RBCs (n = 161) and PRID-treated RBCs (n = 100). The factors examined included lactation number (2.5 � 1.6, range: 1–12), insemination number (6.0 � 2.5, range: 3–19), the interval from calving to next AI (288.0 � 102.1 days, range: 102–797 days), and whether the ET was into the uterine horn ipsilateral or contralateral to the CL in a total of 261 RBCs. Data were analyzed using logistic regression. The results for Exp. 1: 103 cows (96.3%) were confirmed to be in estrus (2.0 � 0.3 days after PRID removal). Although the frequency of estrus was affected by the lactation number (P = 0.014) and the interval from calving to the first AI (P = 0.005), the AI number did not have an affect (P = 0.624). Exp. 2: PRID synchronization had no effect on pregnancy rate (control: 37.3%, 60/161; and PRID-treated: 40.0%, 40/100). For the RBCs, the pregnancy rate was not affected by lactation number (P = 0.093), AI number (P = 0.694), or the interval from calving to next AI (P = 0.762). No significant difference (P = 0.428) in pregnancy rate was observed in cows when the embryos were transferred into the uterine horn contralateral to the CL (43.5%, 20/46), compared to those embryos transferred into the uterus horn ipsilateral to the CL (37.2%, 80/215). In conclusion, our findings suggest that the pregnancy rate may be improved by considering lactation number and the interval from calving to the next AI of RBCs in estrus synchronization using a combination of PRID + PGF2α and AI + ET.


2011 ◽  
Vol 23 (1) ◽  
pp. 255 ◽  
Author(s):  
A. C. Oliveira ◽  
M. C. C. Mattos ◽  
M. R. Bastos ◽  
J. R. S. Gonçalves ◽  
L. H. Lunardi ◽  
...  

The objective of this study was to evaluate the use of pLH in replacement of eCG on the last day of P-36 superstimulatory treatment in Nellore donors. Recent studies demonstrated improvement in embryo production when the last 2 doses of FSH were replaced by eCG. However, consecutive use of eCG in bovine superstimulatory protocols may induce antibody against eCG, decreasing embryo production. Twenty-five Nellore cows were randomly allocated in 4 groups: P-36 (control), P-36/eCG, P-36/LH2, and P-36/LH4. All animals underwent 4 treatments in a cross-over design. Donors received an intravaginal device containing 1.0 g of progesterone (IVD, Primer®, Tecnopec, Sao Paulo, Brazil) and oestradiol benzoate (2.0 mg, IM; Estrogin®, Farmavet, Sao Paulo, Brazil) at a random stage of the oestrous cycle (D0). Cows from the control group were superestimulated with decreasing doses of pFSH (133 mg, IM; Folltropin-V®, Bioniche, Ontario, Canada; D5-8). In the P-36/eCG group, the last 2 doses of pFSH were replaced by 2 doses of eCG (200 IU each dose, IM; Folligon®, Intervet, Boxmeer, the Netherlands). In the P-36/LH2 and P-36/LH4 groups, the last 2 doses of pFSH were replaced by 2 doses of 1 and 2 mg of pLH, respectively (IM; Lutropin®, Bioniche). All animals were treated with prostaglandin F2α (150 μg d-cloprostenol, IM; Prolise®, Tecnopec) on D7, and the IVD was removed 36 h after. Ovulation was induced with 12.5 mg of pLH (IM) on D9, and all animals received fixed-time artificial insemination 12 and 24 h after pLH. Embryo flushing was performed on D16. Data were analysed by ANOVA (Proc Mixed, SAS). There was a significant difference in the number of corpus luteum in the eCG group (19.2 ± 2.4) when compared with the LH2 (12.7 ± 2.0) and LH4 groups (12.3 ± 1.5; P < 0.05). In addition, there was a tendency of lower ovulation rate in the LH2 group as compared with the eCG group (50.6 and 67.8%, respectively; P = 0.06). However, there was no difference in viable embryo yield among groups P-36 (3.3 ± 0.7), P-36/eCG (4.5 ± 0.5), P-36/LH2 (3.7 ± 0.8), and P-36/LH4 (4.2 ± 1.0); P > 0.05. In conclusion, eCG can be replaced by pLH (4.0 mg), in the last day of P-36 protocol, without affecting the production of viable embryos in Nellore cows. The authors acknowledge FAPESP (Sao Paulo, Brazil) for funding and fellowships for A. C. S. Oliveira, M. C. C. Mattos, and M. R. Bastos.


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