175 REPRODUCTIVE PERFORMANCE OF MANGALARGA MARCHADOR MARES AFTER INDUCTION OF OVULATION WITH hCG OR DESLORELIN

2010 ◽  
Vol 22 (1) ◽  
pp. 246
Author(s):  
D. R. Faria ◽  
A. L. N. Boffe ◽  
S. F. Grossi ◽  
A. Gradela
Keyword(s):  
Water Supply ◽  
Embryo Transfer ◽  
Reproductive Performance ◽  
Genetic Improvement ◽  
Induction Of Ovulation ◽  
Embryo Recovery ◽  
Follicle Diameter ◽  
Repeated Use ◽  
Follicle Size ◽  
Fresh Semen

The use of biotechnology, such as AI, embryo transfer, and hormonal protocols, have accelerated the genetic improvement in the equine specie, and inducers of ovulation, such as hCG, are important tools in implementing them. However, the repeated use of ovulation inducers can promote the development of antibodies and undermine their purpose. Thus, a synthetic GnRH, deslorelin, has been used. In this study, we compared the reproductive performance of 44 Mangalarga Marchador donor mares, aged between 5 and 21 years and with sound reproductive history after treatment with hCG or deslorelin. During estrus, mares were examined by transrectal ultrasonography every other day until a follicle of 30 mm in diameter was detected and then daily until detection of a >35-mm follicle and moderate uterine edema. At this time, mares were treated with either 2 mL of saline, i.m. as controls (CON = 16); 2500IU of hCG, i.v. (Chorulon, Intervet Inc., Millsboro, DE, USA; hCG = 14); or 2 mg mL-1 deslorelin in BRT vehicle (BET Pharm, Lexington, KY, USA), i.m. (DES = 14). After treatments, mares were examined at 12-h intervals until ovulation and were inseminated with fresh semen 12 h after ovulation. On Day 8, embryos were recovered and evaluated. All mares were ovulated, and follicle diameters were not different (P > 0.05) at the time of treatment (38 ± 0.029 v. 39 ± 0.029 v. 38 ± 0.029 mm). Embryo recovery was similar among groups (CON, 37.5%; hCG, 42.8%; DES, 50.0%, respectively). The interval from treatment to ovulation did not differ (P > 0.05) between hCG (1.43 +0.56 days) and DES mares (1.14 + 0.36 days), and both were less (P > 0.05) than for controls (CON, 2.94 + 0.77 days). The number of mares that ovulated per ovulation interval were as follows: <24 h = CON: 0%, hCG: 7.14%, and DES: 14.29%, respectively; from 24 to 48 h = 6.25%, 64.29%, and 78.57%; from 49 to 72 h = 37.5%, 28.57%, and 7.14%; >72 h = 56.25%, 0%, and 0%. Time to ovulation was negatively correlated (P < 0.05) with follicle diameter in CON (r = -0.50, P < 0.05) but not for hCG (r = 0.05) or DES (r = 0.022) and was positively correlated with embryo recovery for DES (r = 0.46, P < 0.10), but not hCG (r = 0.23) or CON (r = 0.09). Based on the results, we concluded that hCG and DES effectively synchronize the time of ovulation. Follicle size did not affect the time of ovulation in hCG- and DES-treated mares. We thank the Farm Water supply for the animals and drugs.

Laparoscopy for insemination, embryo recovery and embryo transfer in ewes

1986 ◽  
Vol 1986 ◽  
pp. 66-66
Author(s):  
W. A. C. McKelvey ◽  
J. J. Robinson ◽  
R. P. Aitken
Keyword(s):  
Embryo Transfer ◽  
Operative Time ◽  
Cattle Breeding ◽  
Genetic Traits ◽  
Embryo Recovery ◽  
Surgical Methods ◽  
Rapid Dissemination ◽  
Repeated Use ◽  
Transfer Procedures ◽  
Donor Cows

Embryo transfer has become a widely used technique for the more rapid dissemination of valuable genetic traits in cattle. The rapid uptake of embryo transfer technology by the cattle breeding industry has largely resulted from the development of non-surgical methods for the recovery of embryos from donor cows and for their subsequent implantation into recipient animals. These non-surgical methods not only reduce operative time but permit the repeated use of cows without the risk of formation of post-operative adhesions.Although embryo transfer is a technique commonly used by research workers in the study of certain aspects of reproductive physiology in sheep, there are several problems associated with conventional transfer procedures in this species which have precluded its adoption by the sheep breeding industry.

scholarly journals Ovarian Follicle Growth during Lactation Determines the Reproductive Performance of Weaned Sows

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1012 ◽  
Author(s):  
Tania P. Lopes ◽  
Lorena Padilla ◽  
Alfonso Bolarin ◽  
Heriberto Rodriguez-Martinez ◽  
Jordi Roca
Keyword(s):  
Reproductive Performance ◽  
Post Partum ◽  
Ovarian Follicle ◽  
Transrectal Ultrasound ◽  
Great Variability ◽  
Early Lactation ◽  
Follicle Growth ◽  
Follicle Diameter ◽  
Follicular Size ◽  
Follicle Size

Factors causing variability in ovarian follicle size among weaned sows are not well known. This field study aimed to disclose influencing factors and evaluate if the differences at weaning were established during lactation. Ovaries were scanned using transrectal ultrasound. The first experiment was conducted over a year with 191 randomly chosen sows that were hierarchically grouped (p < 0.001) according to ovarian follicle diameter reached at weaning: Small (0.20–0.30 cm; n = 37), medium (0.31–0.39 cm; n = 75), and large (0.40-1.00 cm; n = 69). Sows with small follicles showed a higher incidence of post-weaning anestrus (p < 0.01), longer wean-to-estrus/ovulation intervals (p < 0.01) and farrowing smaller litters (p < 0.05). Ovaries with small follicles were more common among sows weaned in summer–autumn than in winter–spring (p < 0.01) and among sows of lower parity (1–3) (p < 0.05). In the second experiment, with 40 sows randomly chosen at farrowing, the ovaries were scanned at 7, 14, and 21 d post-partum. Sows showed great variability in ovarian follicular size during lactation with a consistent relationship between the three measurement times (r = 0.84, p < 0.01). Follicle size was smaller in sows nursing in summer–autumn than in winter–spring (p < 0.05). In conclusion, early lactation dictates the great variability in ovarian follicular diameter at weaning shown by sows. Sows with smaller follicles at weaning had longer intervals for estrus and ovulation and smaller litters at farrowing and they were in greater numbers among sows weaned during the summer and fall and among those with fewer previous farrowing.

scholarly journals The use of multiple ovulation, embryo cryopreservation and embryo transfer techniques to facilitate movement of genetic material between countries

2018 ◽  
Vol 53 (3) ◽  
pp. 237
Author(s):  
K. STAMATARIS (Κ. ΣΤΑΜΑΤΑΡΗΣ) ◽  
K. DELIGIANNIS (Κ. ΔΕΛΗΓΙΑΝΝΗΣ) ◽  
T. LAINAS (Θ. ΛΑΪΝΑΣ) ◽  
G. ARSENOS (Γ. ΑΡΣΕΝΟΣ)
Keyword(s):  
Survival Rate ◽  
Ethylene Glycol ◽  
Embryo Transfer ◽  
Genetic Material ◽  
Embryo Cryopreservation ◽  
Embryo Survival ◽  
Embryo Recovery ◽  
Multiple Ovulation ◽  
Large Numbers ◽  
Fresh Semen

The objective of the study was to evaluate the use multiple ovulation and embryo transfer techniques in an indigenous Greek dairy breed of sheep. We stimulated selected donor ewes of the Karagouniko breed to produce large numbers of embryos after the induction of multiple ovulations by gonadotropin treatment (superovulatory response). A total of 50 Greek Karagouniko ewes were synchronised into oestrus using progestagen pessaries and superovulated for embryo transfer using ovine FSH. Six days following laparoscopic insemination with fresh semen ewes were flushed surgically and embryos collected. Subsequently, the embryo recovery, along with embryo cryopreservation, embryo survival and quality were assessed. The Karagouniko donor ewes achieved a mean ovulation rate of 11.9 (SE. 0.89). The ova Recovery rate was 80,9% and 87,6% of the ova recovered being fertilised. A total of 327 (77,5%) of the viable embryos were assessed as being of sufficient quality for cryopreservation. The embryos ranged from late morulae to expanded blastocyst and were frozen via a 3-step process in 1.5 M ethylene glycol following repeated washing and trypsination. Cryopreserved embryos were frozen and then transported to Scotland, UK. There, embryos were thawed rapidly and re-hydrated via a 2 step sucrose/ethylene glycol gradient. A total of 92.4% of embryos frozen remained suitable for transfer semi-surgically into synchronized Scottish Blackface ewes. 183 embryos were transferred in total with a 66.1% survival rate. The survival rate of frozen thawed blastocysts(75%) was significantly greater than (P<0.01) that for morulae (48%). It was concluded that MOET could be successfully applied in Greek dairy breeds of sheep as a means for genetic improvement. Frozenembryos could be a successful medium for the transportation of ovine genetic material from and to Greece, however, most likely the choice of embryonic stage for cryopreservation is crucial.

The use of embryo transfer in ruminant genetic improvement programmes

1992 ◽  
Vol 1992 ◽  
pp. 6-6
Author(s):  
G Simm
Keyword(s):  
Gene Transfer ◽  
Disease Control ◽  
Embryo Transfer ◽  
Genetic Improvement ◽  
Genetic Material ◽  
Small Ruminants ◽  
Embryo Recovery ◽  
Multiple Ovulation ◽  
Import And Export

Over the course of the last 40 years or so increasingly reliable procedures have been developed for multiple ovulation, embryo recovery and embryo transfer, initially for cattle (see review of Woolliams and Wilmut, 1989) and, more recently, for small ruminants (McKelvey and Robinson, 1986). During this time a number of applications have been proposed or practised. These include uses in (i) within-breed genetic improvement programmes, (ii) the import and export of genetic material (offering potential advantages in economy, animal welfare and disease control), (iii) accelerating breed substitution by multiplication of newly introduced breeds and (iv) conservation of genetic material (by freezing embryos) from valuable individual animals, or from rare or endangered breeds or species. Additionally, there are several new ‘reproductive’ procedures available or being developed for use in animal production (eg. in vitro fertilisation, embryo sexing, cloning, gene transfer) which hinge on the use of embryo transfer. These are discussed in detail by Woolliams and Wilmut (1989) and in the following two papers. The aim of this paper is to examine the first of the applications listed above - the use of multiple ovulation and embryo transfer (MOET) in within-breed genetic improvement programmes.

scholarly journals The Effect of A PRID®Delta-Based Estrus Synchronization Protocol On Pregnancy Rates In Cows With No Estrus Symptoms

2022 ◽  
Author(s):  
Murat Can Demir ◽  
Cihan Kaçar ◽  
Umut Çağın Arı ◽  
Semra Kaya ◽  
Oğuz Merhan ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Pregnancy Rates ◽  
Dominant Follicle ◽  
Serum Progesterone ◽  
Blood Samples ◽  
Follicle Diameter ◽  
Follicle Size ◽  
Equine Chorionic Gonadotropin

Abstract The present study aimed to determine the effects of progesterone-based gonadotropin-releasing hormone (GnRH), prostaglandin F2α (PGF2α), and equine chorionic gonadotropin (eCG) injections on progesterone profiles and pregnancy rates in cows with no estrus symptoms within 60 days after parturition. A total of 80 cows were included in the study. All animals had the progesterone-releasing device PRID®Delta placed intravaginally for nine days with an injection of GnRH. On the eighth day, PGF2α was injected, and PRID®Delta was removed from the vagina on day nine. Artificial insemination was carried out 60 hours after PRID®Delta removal. In half of the animals (n = 40), 600 IU of eCG was injected when PRID®Delta was removed on the ninth day before artificial insemination 60 hours later. Blood samples were taken from the tail vein on days 0 and 8 to determine progesterone levels. The pregnancy rate in the group that received eCG was 37.5%, while it was 27.5% in those that did not (P = 0.4). While the dominant follicle diameter was 15.5 mm in cows injected with eCG during timed artificial insemination, the follicle diameter was 12.4 mm in cows with no eCG injection (P <0.001). There were no differences in serum progesterone values in blood samples taken until the time of artificial insemination. However, progesterone values in the blood taken during artificial insemination were 0.94 ng/ml in the eCG- group and 0.72 ng/ml in the eCG+ group (P <0.05). As a result, it was determined that eCG injections, in addition to progesterone-based GnRH and PGF2α applications, increased the pregnancy rates in cows without symptoms of estrus. The dominant follicle diameter was larger in cows treated with eCG during artificial insemination; however, follicle size did not increase the pregnancy rate.

115 FOLLICULAR GROWTH AND BLOOD FLOW OF THE DOMINANT FOLLICLE IN CROSSBRED RECIPIENTS TREATED WITH eCG

2014 ◽  
Vol 26 (1) ◽  
pp. 171
Author(s):  
M. P. Palhao ◽  
N. S. Junior ◽  
C. R. B. Guimarães ◽  
C. A. C. Fernandes ◽  
M. E. O. Ferreira ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Sao Paulo ◽  
Ovulation Rate ◽  
São Paulo ◽  
Follicular Growth ◽  
Dominant Follicle ◽  
Follicle Diameter ◽  
Transfer Protocol

This study aimed to explore changes in follicle diameter and blood flow of the dominant follicle (DF), in ovulation and embryo transfer rates, after inclusion of eCG in a protocol for timed embryo transfer. The effect presence or absence of a corpus luteum (CL) at the start of treatment was also included. Crossbred heifers (n = 116, Bos taurus × Bos indicus), with (n = 61) or without (n = 55) CL, were included in the same hormone protocol: Day 0 (D0), insertion of progesterone (P4) device (1.0 g, Sincrogest®, Ouro Fino, São Paulo, Brazil) and 2 mg of oestradiol benzoato (EB, Sincrodiol®, Ouro Fino); D8, removal of P4 device and injection of sodium Cloprostenol (0.250 mg mL–1, Sincrocio®, Ouro Fino). On D8, the animals with and without CL – at the beginning of the protocol – were equally divided into 2 groups (G): G1 – injection of 300 IU (2.0 mL) of eCG (n = 56; Synchro eCG®, Ouro Fino); G2 – 2.0 mL of saline (n = 60). The ovulations were synchronized with 1 mg of EB on D9. From D8 to D11, the diameter of the DF and blood flow in its wall were recorded daily (M5 ultrasound with colour Doppler technology, 7.5-MHz linear array, DPS medical equipment, São Paulo, Brazil). Approximately 100 frames in colour-flow mode, containing entire cross-sections of the DF, were recorded during each examination. The area of the follicular wall with coloured pixels was measured with ImageJ software (Image Processing and Analysis in Java) from the frame with the largest blood flow signal. Before embryo transfer, all heifers were evaluated, and those with good-quality CL received frozen/thawed embryos (ethylene glycol 1.5 mol). Follicle diameter and blood flow area were compared between groups with or without CL before timed embryo transfer protocol and between eCG treatments. The PROC GLM procedure of SAS (version 9.0) and the t-test were used to assess the differences between means. Pregnancy diagnosis was performed on D35. Embryo transfer (ET) rate of the recipients and pregnancy rate were compared between CL or eCG treatments by the chi-squared test. Ovarian status, before hormone protocol, did not change (P > 0.05) the follicular growth of the DF. However, ovulation rate (78.8 v. 65.4%, P < 0.05) and ET rate (78.7 v. 65.4%, P < 0.05) were higher in animals with CL on D0. From D8 to D10, the inclusion of eCG did not affect (P > 0.05) follicular growth and blood flow of the DF. The time effect (P < 0.0001) for follicular blood flow had shown an increase in area of blood flow 24 h after implant removal (7.7 ± 0.7,b 10.2 ± 0.7,a and 12.3 ± 1.0a mm2, for Days 8, 9, and 10, respectively). The eCG did not affect (P > 0.05) the ovulation rate (71.4 and 73.3%, respectively, eCG and no eCG), however, approached an increased (P < 0.06) ET rate (78.8 v. 66.7%). The overall pregnancy rate (51.2%, 43/84) was not affected (P > 0.05) by evaluated variables. In summary, the addition of 300 IU of eCG on D8 of the timed embryo transfer protocol did not change the development of DF but increased the ET rate of the recipients. Biotran, FAPEMIG (project number APQ-1454-12), and CnPQ are acknowledged.

108 COMPARATIVE EFFICIENCY OF GONADOTROPIN-RELEASING HORMONE AND LUTEINIZING HORMONE IN THE INDUCTION OF OVULATION IN SUPEROVULATED ALPACAS

2014 ◽  
Vol 26 (1) ◽  
pp. 168
Author(s):  
H. W. Vivanco-Mackie ◽  
M. D. Ponce Salazar ◽  
M. M. Gonzales ◽  
M. A. Tapia
Keyword(s):  
Gnrh Agonist ◽  
Recovery Rate ◽  
Pearson Correlation ◽  
Animal Health ◽  
Gonadotropin Releasing Hormone ◽  
Corpora Lutea ◽  
Peruvian Andes ◽  
Releasing Hormone ◽  
Induction Of Ovulation ◽  
Embryo Recovery

Alpacas are induced ovulators, responding to copulation and (or) exogenous application of ovulation-inducing hormones. The objective of this study was to determine the efficiency of the injection of a gonadotropin-releasing hormone (GnRH) agonist versus LH in the induction of ovulation and the presence and size of non-ovulated follicles at the time of embryo collection and its relationship to the yield of transferable embryos in superovulated alpacas. Twenty-one adult (3 to 7 years old) female alpacas under extensive grazing at 4300 m elevation in the Peruvian Andes that had been synchronized and treated for superovulation were induced to ovulate 6 days after the application of the superovulatory hormone (1000 IU of eCG, Folligon®, Intervet International BV, Boxmeer, the Netherlands) by mating with fertile males and injection immediately after copulation of either an IM dose of 0.0084 mg of buserelin acetate (Buserelina Zoovet®, Laboratorio Zoovet, Santa Fe, Argentina) to 10 alpacas (T1) or an IM dose of 5-mg Armour standard of LH (Lutropin®, Bioniche Animal Health, Belleville, ON, Canada) to 11 alpacas (T2). All alpacas had a second mating 12 h after the first mating and were subjected to ovarian inspection by ultrasonography and previous embryo collection by nonsurgical transcervical embryo flushing 6.5 days after the first mating. On average, the embryo recovery rate for T1 was 34.6% and there were 7.8 ± 3.99 corpora lutea (CL), 2.7 ± 4.08 collected embryos, and 3.6 ± 2.95 total, 0.5 ± 0.85 small (<6 mm), 1.8 ± 1.99 medium (≥6 but ≤14 mm), and 1.3 ± 2.11 large (≥15 mm) non-ovulated follicles. For T2, the embryo recovery rate was 59.4% and there were 6.73 ± 1.49 CL, 4.0 ± 2.57 collected embryos, and 0.64 ± 0.81 total, 0.0 ± 0.0 small, 0.36 ± 0.67 medium, and 0.27 ± 0.47 large non-ovulated follicles. The differences between treatments were nonsignificant (P > 0.05) for all the parameters; however, there was a clear tendency for a better recovery rate, more embryos collected, and lower number of non-ovulated follicles in T2. The Pearson correlation coefficient between the presence of large follicles in the ovaries at the time of embryo collection and the total number of embryos collected was negative (r = –0.26) and highly significant (P ≤ 0.001). The use of LH for ovulation induction of superovulated alpacas seems to be more advisable than the use of GnRH agonist; further comparisons with larger number of observations per treatment are recommended. This study was financed by the Peruvian Fund for Innovation, Science and Technology (FINCYT).

157 EFFECT OF DENSITY GRADIENT SELECTION ON EMBRYO RECOVERY RATES OF FRESH AND COOLED STALLION SEMEN

2013 ◽  
Vol 25 (1) ◽  
pp. 227
Author(s):  
F. Papa ◽  
M. Carmo ◽  
P. Papa ◽  
J. Dell'Aqua ◽  
M. Alvarenga
Keyword(s):  
Plasma Membrane ◽  
Density Gradient ◽  
Recovery Rate ◽  
Ovulation Induction ◽  
Membrane Integrity ◽  
Recovery Rates ◽  
Plasma Membrane Integrity ◽  
Embryo Recovery ◽  
Fresh Semen ◽  
Sperm Recovery

The aim of this study was to improve the spermatic kinetic parameters from stallions with poor quality of fresh and chilled semen by the use of density gradient Equipure™ (Nidacon, Mölndal, Sweden). Semen from 5 Quarter Horse stallions aged 8 and 16 years with history of low embryo recovery rates were used. The kinetics sperm evaluation was performed by computerized semen analysis (CASA) and plasma membrane integrity with fluorescent probes. The average motility parameters for fresh semen before selection were total motility (MT) 60%, progressive motility (PM) 30%, and plasma membrane integrity (IMP) 60% and for cooled semen (24 h at 5°C) were: MT 50%, MP 18%, and 50% IMP. For the group of fresh and cooled semen with no density gradient selection (NS), mares were inseminated with 1 billion viable sperm diluted in skim milk extender in the uterine body, 24 h after ovulation induction with 1 mg of deslorelin. For EquipureTM selection group (SE) semen was concentrated through Spermfilter membrane™ and resuspended in 5 mL of BotuSemenTM (BotupharmaTM, Brazil). In a 15 mL conic tube 5 mL of EquipureTM was added and another part containing 5 mL of the resuspended sperm was slowly added over the EquipureTM column. The 15 mL conic tube was centrifuged at 400g for 20 min. After centrifugation, the sperm pellet was carefully aspirated and to the pellet was resuspended in 4 mL of BotucrioTM. The sperm recovery rate with EquipureTM was 40%. Deep uterine AI was performed 24 h after ovulation induction with 1 mg of deslorelin. Data were analyzed by ANOVA followed by Tukey’s test (P < 0.05). The analysis of semen after EquipureTM selection resulted in average: 75, 35, 65, and 40%, respectively, for MT, MP, and IMP index and sperm recovery. The embryo recovery rate from the 5 stallions showed the following results: Stallion 1 (fresh semen): 12 mares (NS)/4 embryos (33%) and for group SE 22 mares/16 embryos, (72%; P ≤ 0.05). Stallion 2 (fresh semen): 9 mares (NS)/4 embryos, (44%) and for group SE, 12 mares/8 embryos (66%; P > 0.1). Stallion 3 (fresh semen): 4 mares (NS)/1 embryo (25%) and 7 mares for SE/4 embryos (57%; P > 0.1). Stallion 4 (chilled semen): 4 mares (NS)/0 embryo 0% and for SE group 8 mares/6 embryos 75%; P ≤ 0.001). Stallion 5 (chilled semen): 10 mares (NS)/2 embryos (20%) and for SE 6 mares/3 embryos (50%; P > 0.1). For the overall results, 39 inseminations were performed on the no selected group and 11 embryos recovered (28%) for the selected group 55 inseminations and 37 embryos recovered (67%; P < 0.01). The results clearly showed that selection by sperm density gradient EquipureTM was a very effective technique that allowed an improvement on semen quality and fertility. The authors acknowledge support from FAPESP and Botupharma.

181 CHANGES IN THE BODY CONDITION STATUS OF DONOR MARES THROUGHOUT THE BREEDING SEASON AND THEIR RELATIONSHIP WITH REPRODUCTION TRAITS

2010 ◽  
Vol 22 (1) ◽  
pp. 249
Author(s):  
P. G. Rodrigues ◽  
C. M. Raymundo ◽  
M. C. M. G. Miranda ◽  
J. B. Bastos ◽  
J. C. DeSouza
Keyword(s):  
Breeding Season ◽  
Body Condition ◽  
Recovery Rate ◽  
Fixed Effects ◽  
Mixed Model ◽  
Body Condition Score ◽  
Follicular Phase ◽  
The Body ◽  
Embryo Recovery ◽  
Follicle Diameter

The objective was to investigate the relationship between changes in body condition on reproductive traits of donor mares in an embryo collection program. Fifty-six non-pregnant mares, 3 to 18 years old, were studied from August 2008 through April 2009. Body condition score (BC; 1-9 scale, thin to obese) was estimated monthly. Body weight and tail and rib s.c. fat depths (SF) were measured monthly. SF was determined by ultrasound. Dominant follicle diameter (DF) was measured daily during the follicular phase. Mares were artificially inseminated and embryo transfers were conducted 6 d after ovulation. Analyses were performed with SAS® (SAS Institute Inc., Cary, NC, USA). Age classes were as follows: age 1, 3 to 6.9 (n = 17); age 2, 7 to 12.9 (n = 25), and age 3, ≥13 years (n = 14). Months in experiment were T1 to T6. BC classes were as follows: B1, <6.5; B2, 6.5 to 6.9; B3, 7.0 to 7.5; and B4, >7.5. Embryo recovery rate was compared by chi square. Effects of month and age on BC, weight, and SF were analyzed by a mixed model. Age, BC, and month fixed effects on DF diameter were analyzed by ANOVA with mare within class as the error term. Means were compared by contrasts. BC was higher (P = 0.02) in older mares (6.78 ± 0.2 and 6.93 ± 0.2 in age 1 and age 2 v. 7.25 ± 0.2 in age 3) and increased (P = 0.009) with time (from 6.79 ± 0.20 to 7.42 ± 0.26 for T1 to T6, respectively). Weight (kg) was not associated with age but increased (P = 0.03) throughout the experiment. Tail fat increased with age (P = 0.04) and decreased with increasing months on experiment (P = 0.02). DF diameter increased daily through the follicular phase (P < 0.0001) and was smaller (P < 0.05) in mares with lower body condition (33.80 ± 0.31 in BC1 v. 34.17 ± 0.31 mm in BC4). DF diameter decreased (P < 0.01) with month on study. Embryo recovery rate was not affected by age or BC but was lower (P = 0.003) in mares that ovulated follicles smaller than 40 mm compared to mares ovulating follicles greater than 40 mm. BC above 6.5 was associated with higher embryo recovery rate, which was, in turn, correlated positively with DF diameter. Thus, our results support the use of BC scoring to predict performance in equine embryo transfer programs. Body condition scoring was not a good indicator of SF under the current experimental conditions because SF decreased during the breeding season. BC scoring may indicate lean tissue gain, which may be a better indicator of reproductive efficiency in mares. FAPEMIG, CAPES, Haras El Far.

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