166 Comparison of the 7 and 7 Synch protocol and the 7-day CO-Synch + controlled internal drug release protocol among recipient beef cows in an embryo transfer programme

2020 ◽  
Vol 32 (2) ◽  
pp. 210
Author(s):  
R. C. Bonacker ◽  
K. R. Gray ◽  
C. A. Breiner ◽  
J. M. Anderson ◽  
D. J. Patterson ◽  
...  
Keyword(s):  
Drug Release ◽  
Embryo Transfer ◽  
Body Condition Score ◽  
Prostaglandin F2α ◽  
Beef Cows ◽  
Corpora Lutea ◽  
Frozen Embryos ◽  
Condition Score ◽  
Recommended Guidelines ◽  
Mixed Groups

An experiment was designed to evaluate the effectiveness of the recently developed 7 and 7 Synch protocol to synchronise oestrus and ovulation among recipients before embryo transfer (ET). Postpartum beef cows (n=1358) across 13 locations were assigned to either the 7-day CO-Synch + controlled internal drug release (CIDR) protocol or the 7 and 7 Synch protocol before oestrus detection and subsequent ET. Cows were pre-assigned to balanced treatments within location based on age and days postpartum, and body condition score was recorded at ET. Cows assigned to the 7-day CO-Synch + CIDR protocol were administered gonadotrophin-releasing hormone (GnRH; 100µg of gonadorelin acetate) on Day 0, an intravaginal CIDR insert (1.38g of progesterone) from Day 0 to 7, and prostaglandin F2α (PG; 25mg of dinoprost tromethamine) coincident with CIDR removal on Day 7. Cows assigned to the 7 and 7 Synch protocol were administered PG (25mg of dinoprost tromethamine) coincident with CIDR insertion on Day −7, GnRH (100µg of gonadorelin acetate) on Day 0, and PG (25mg of dinoprost tromethamine) coincident with CIDR removal on Day 7. The 7 and 7 Synch protocol was hypothesised to enhance response to GnRH administration on Day 0 among mixed groups of oestrous cycling and anestrous cows, ultimately resulting in improved oestrous response and synchrony of oestrus before ET. Cows were observed for visible signs of oestrus following oestrus synchronisation, with GnRH (100µg of gonadorelin acetate) administered to cows failing to express oestrus during the detection period. Length of the detection period varied among locations but was consistent across treatments within location. Embryo transfer was performed approximately 7 days after oestrus or GnRH administration. Presence of corpora lutea (CL) was determined via transrectal palpation by a single veterinarian blinded to treatment, and embryos were transferred only to cows with palpable CL. Embryo transfer was performed using fresh or frozen embryos staged and graded according to IETS recommended guidelines, with embryo information recorded for each recipient. Data were analysed using the PROC GLIMMIX procedure of SAS (SAS Institute Inc.). Proportion of cows expressing oestrus was improved (P<0.0001) among cows assigned to the 7 and 7 Synch protocol (86% (529/615) vs. 76% (488/640)). The proportion of recipient females with palpable CL tended to be greater (P=0.07) among cows assigned to the 7 and 7 Synch protocol (82% (478/586) vs. 80% (451/565)). Among cows that expressed oestrus, a greater proportion (P<0.01) had palpable CL following the 7 and 7 Synch protocol (88% (466/529) vs. 86% (418/488)). Consequently, irrespective of embryo type received, the proportion of recipients pregnant to ET was greater (P<0.01) following the 7 and 7 Synch protocol (39%; 263/668) compared with the 7-day CO-Synch + CIDR protocol (33%; 228/690). In summary, the 7 and 7 Synch protocol improved the likelihood of oestrus expression in recipient cows, increased the proportion eligible to receive an embryo, and resulted in greater pregnancy rate to ET.

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.

8 SYNCHRONIZATION OF OVULATION IN DAIRY HEIFERS USING A SHORTENED ESTRADIOL-BASED PROTOCOL THAT PROVIDES FOR A LENGTHENED PROESTRUS

2014 ◽  
Vol 26 (1) ◽  
pp. 118 ◽  
Author(s):  
M. Re ◽  
J. J. de la Mata ◽  
G. A. Bo
Keyword(s):  
Body Condition Score ◽  
Prostaglandin F2α ◽  
Beef Cows ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Treatment Protocols ◽  
Dairy Heifers ◽  
Buserelin Acetate ◽  
Condition Score ◽  
The Mean

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.

101 Treatment with gonadotrophin-releasing hormone on Day 7 or 21 does not reduce pregnancy loss in dairy heifers receiving invitro-produced embryos

2020 ◽  
Vol 32 (2) ◽  
pp. 176
Author(s):  
B. J. Duran ◽  
R. V. Sala ◽  
P. L. J. Monteiro ◽  
C. Gamarra ◽  
M. Fosado ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Pregnancy Loss ◽  
Body Condition Score ◽  
Prostaglandin F2α ◽  
P Value ◽  
Releasing Hormone ◽  
Dairy Heifers ◽  
Condition Score ◽  
Pregnancy Status ◽  
Gonadotrophin Releasing Hormone

Previous research has shown that induction of an accessory corpus luteum (CL) by administration of gonadotrophin-releasing hormone (GnRH) on Day 5 increases circulating progesterone and reduces pregnancy loss between Days 33 and 60 in heifers receiving invitro-produced (IVP) embryos. Therefore, the objective of the present study was to determine whether timing of induction of an accessory CL influenced pregnancy loss in IVP recipients. Holstein heifers (n=1,658) were synchronized using a modified 5-day CIDR CO-Synch protocol. Briefly, heifers received an intravaginal progesterone device (CIDR) on Day −8, Day −3: CIDR removed and first prostaglandin F2α (PGF2α) treatment, Day −2: second PGF2α, and Day 0: GnRH (G1, 100µg of gonadorelin acetate). Oestrus expression was evaluated on Day 0 with the use of an oestrus detection device. Transfer of fresh IVP embryos was performed on Day 7±1 after G1. At the time of transfer, heifers were randomly assigned, in a 2×2 factorial design, to receive GnRH (200µg of gonadorelin acetate) or remain as Control (untreated) at two different times: Day 7 (time of embryo transfer (ET)) or Day 21. Thus, the following groups were formed: Control-Control (n=410); Control-GnRH (n=409); GnRH-Control (n=419); and GnRH-GnRH (n=420). All heifers were evaluated by transrectal ultrasonography to determine number, size, and location of CL on Days 5, 14, 21, 28, 32, and 60 and pregnancy status on Days 28, 32, and 60. Data collected from each heifer included embryo stage and quality, oestrus expression, body condition score, number of transfers, and technician. Pregnancies per embryo transfer (P/ET) and pregnancy loss data were analysed by logistic regression (SAS 9.4). Ovulation to Day 7 treatment was greater (P<0.01) in GnRH treated heifers (70.0%; 585 out of 836) than in untreated Controls (2.7%; 22 of 819). Ovulation to Day 21 treatment was determined only in animals pregnant at Day 28 and was greater (P<0.01) in heifers treated with GnRH (37.6%; 153 of 407) than in untreated controls (1.0%; 4 of 390). There was no effect of Day 7 treatment (P>0.68) or Day 21 treatment (P>0.18), nor a Day 7×Day 21 treatment interaction (P>0.48) on P/ET at Day 32 or 60 (Table 1). Treatment with GnRH on Day 7 or 21 did not alter pregnancy loss between Days 32 and 60 (P>0.10). Heifers with an accessory CL present at Day 32 (11.7%; 41 of 350) had similar (P=0.55) pregnancy loss compared with heifers with no accessory CL (14.4%; 54 of 375). The number of CL present on Day 32 did not affect (P=0.23) pregnancy loss; however, heifers with 3 CL (4.9%; 3 of 61) tended (P<0.10) to have reduced pregnancy loss compared with heifers with 1 CL (14.4%; 54 of 375) or 2 CL (13.2%; 38 of 289). In conclusion, treatment with GnRH on Day 7 or 21 induced an accessory CL; however, it did not affect P/ET on Days 32 or 60 and pregnancy loss. Table 1.Pregnancies per embryo transfer (P/ET) and pregnancy loss in embryo recipients based on timing of treatment with gonadotrophin-releasing hormone (GnRH) Treatment P/ET Day 32% (n) P/ET Day 60% (n) Pregnancy loss% (n) Day 7 Day 21 Control Control 42.4 (410) 36.1 (410) 15.0 (174) GnRH 46.0 (409) 40.7 (409) 11.7 (188) GnRH Control 43.7 (419) 36.8 (419) 15.9 (183) P-value GnRH 43.1 (420) 38.8 (420) 10.0 (181) Day 7 treatment 0.68 0.72 0.96 Day 21 treatment 0.51 0.18 0.11 Interaction 0.48 0.66 0.71

104 FACTORS AFFECTING PREGNANCY RATES AND EMBRYO/FETAL LOSSES IN RECIPIENTS RECEIVING IN VITRO-PRODUCED EMBRYOS BY FIXED-TIME EMBRYO TRANSFER

2017 ◽  
Vol 29 (1) ◽  
pp. 160
Author(s):  
A. Tribulo ◽  
A. Cedeño ◽  
B. Bernal ◽  
S. Andrada ◽  
J. L. Barajas ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Body Condition Score ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Device Removal ◽  
Releasing Hormone ◽  
Condition Score

A retrospective analysis evaluated pregnancy rates and embryo losses with in vitro-produced embryos in a commercial embryo transfer program on 15 different beef farms. Recipients were beef cows and heifers (n = 1841) that were synchronized with 5 different protocols and transferred at a fixed-time (FTET). Recipients were examined by ultrasonography on Day 0, and those with a corpus luteum (CL) or a follicle ≥8 mm in diameter and with body condition score 2 to 4 (1 to 5 scale) were synchronized. The synchronization treatments were as follows. (T1) Recipients received an intravaginal device with 0.5 g of progesterone plus 2 mg of oestradiol benzoate on Day 0; device removal, plus 500 μg of cloprostenol (prostaglandin F2α), 400 IU of eCG, and 0.5 mg of oestradiol cypionate on Day 8; and FTET on Day 17. (T2) This treatment was similar to T1 but 1 mg of oestradiol cypionate was injected at device removal instead of 0.5 mg of oestradiol cypionate. (T3) This treatment was similar to T1 except that animals were tail-painted on Day 8 and observed on Day 10. Those with the tail-paint intact on Day 10 received 100 μg of gonadorelin (gonadotropin-releasing hormone) and all recipients were FTET on Day 17. (T4) Recipients received a progesterone device on Day 0; device removal, prostaglandin F2α, and eCG on Day 5; gonadotropin-releasing hormone on Day 8; and FTET on Day 15. (T5) Recipients received a progesterone device and 2 mg of oestradiol benzoate on Day 0; device removal, prostaglandin F2α, and eCG on Day 6; gonadotropin-releasing hormone on Day 9; and FTET on Day 16. On the day of FTET all recipients with CL ≥18 mm in diameter (G1), ≥16 and <18 mm in diameter (G2), and ≥14 mm and <16 mm in diameter (G3) received in vitro-produced fresh embryos. Pregnancy was diagnosed by ultrasonography at 30 and 60 days of gestation, and data were analysed by logistic regression. The overall proportion of recipients synchronized that were FTET was 80.8% (1487/1841), with a 30-day pregnancy rate to FTET (P/FTET) of 45.6% (678/1487) and the rate of 30- to 60-day embryo/fetal loses on the 528 recipients that were re-checked at 60 days was 12.8% (68/528). There were no significant differences in P/FTET among operators, animal category, time of the year, embryo stage, or body condition score; however, there was a significant effect of farm (P < 0.001) and CL diameter (P < 0.05), but no interaction between CL diameter and farm or treatment (P > 0.1). Recipients with G1 (443/953, 46%) and G2 (221/462, 47%) CL had higher pregnancy rates than those with G3 CL (23/71, 32%). There was a significant effect of synchronization treatment on the proportion of recipients transferred and on P/FTET (P < 0.01) that was highly influenced by farm (farm by treatment interaction P < 0.01). The proportions of recipients selected for embryo transfer were as follows: T1: 386/486, 79.4%; T2: 233/331, 70.3%; T3: 342/377, 90.7%; T4: 126/160, 78.7%; and T5: 400/487, 82.1%. The P/FTET were as follows: T1: 190/386, 49.2%; T2: 96/233, 41.2%; T3: 175/342, 51.1%; T4: 49/126, 38.8%; and T5: 168/400, 42.0%. Although 30- to 60-day embryo/fetal losses were not influenced by synchronization treatments, they were highly influenced by farm (P < 0.001) and ranged from 0 to 34.5%. In conclusion, P/FTET in a commercial program with beef in vitro-produced embryos was influenced by factors related to the recipient (CL diameter) and the environment (farm), whereas embryo/fetal losses were influenced by farm but not treatment or recipient factors.

145 FACTORS AFFECTING PREGNANCY RATE FOLLOWING TIMED EMBRYO TRANSFER PROGRAM IN CATTLE UNDER FIELD CONDITIONS

2009 ◽  
Vol 21 (1) ◽  
pp. 172 ◽  
Author(s):  
F. N. Scenna ◽  
C. J. Munar ◽  
I. Mujica ◽  
E. Martin ◽  
P. Lafarga ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Embryo Development ◽  
Body Condition ◽  
Body Condition Score ◽  
Uterine Horn ◽  
Field Conditions ◽  
Successful Outcome ◽  
Frozen Embryos ◽  
Condition Score

Hormonal estrus synchronization followed by heat detection of recipient animals is a widely used technique in embryo transfer (ET) programs around the world. However, the successful outcomes of ET rely heavily on appropriate heat detection of recipient animals. Additionally, limited availability of personnel and time to detect heat makes ET impractical at times. Therefore, pregnancy rates (PR) following a timed embryo transfer (TET) program were evaluated taking into account different variables of recipient cows, donor embryos, and season of transfer under field conditions in Argentina. Recipient cows were synchronized utilizing a progesterone (P4) intravaginal device (DIB, Syntex, Argentina) for 7 days. On Day 0 (day of DIB insertion) 2 mg of estradiol benzoate (EB) i.m. was administered and immediately after DIB removal on Day 7, 500 μg of D(+) Cloprostenol i.m. (PG, Ciclase, Syntex), 400 IU of eCG i.m. (Novormon, Syntex) plus 1 mg of cypionate estradiol i.m. (ECP; König, Agentina) were administered to all recipient cows. Fresh (n = 1746) and frozen (n = 2047) beef bovine embryos were nonsurgically transferred into recipient cows on Day 9 after PG. The effects of body condition score (1–9, BCS I: ≤5, n = 804 and BCS II: ≥6, n = 2989), corpus luteum (CL) score (CL1: prominent papilla, n = 932, CL2: small papilla, n = 2028, and CL3: asymmetric, n = 833), location of embryo placement in uterine horn (upper, n = 3566, and lower, n = 227), and type of recipient such as heifer (n = 487), lactating (n = 1010), or dry cows (n = 2296) on PR were evaluated. Additionally, stage of embryo development (4–7), quality (1–3), and season of transfer (spring, summer, fall, and winter) were included in the analysis. Pregnancy rate was confirmed by rectal palpation 60 days after ET. Data were first screened by chi square and then analyzed by Proc Logistic of SAS (SAS Institute Inc., Cary, NC). Overall PR was 54.7%. body condition score, CL, type of recipients, stage of embryo development, and year were not significantly (P > 0.05) associated with PR. As expected, cows that received direct fresh embryos had 1.49 times greater odds of conceiving (odds ratio, OR = 1.49, 95% CI: 1.22 to 1.82) than those receiving frozen embryos. Additionally, cows receiving embryos graded as quality 1 had greater probability to conceive (OR = 1.62, 95% CI: 1.34 to 1.95, or OR = 1.64, 95% CI: 1.25 to 2.21) compared to quality 2 or 3 respectively. Moreover, embryos placed into the upper portion of uterine horn were more likely (OR = 1.48) to conceive than those placed in the lower uterine portion. Regardless of embryos and recipient cow variables analyzed, there was a greater probability for cows to conceive during winter (OR = 1.41, 95% CI: 1.13 to 1.95) as compared with summer. In conclusion, synchronized recipient animals for a TET program resulted in acceptable PR for both fresh and frozen embryos. Results suggested that the quality and location of embryos (upper portion) in uterine horn were the most important variables associated with PR in recipient cows. Therefore, TET is a viable and practical option allowing a successful outcome for many beef operations where availability of personnel is limited.

scholarly journals 169PREGNANCY RATES OF THREE DIFFERENT RECIPIENT POOLS IN A COMMERCIAL BOVINE OPU/IVP PILOT TRIAL-NEW ZEALAND

2004 ◽  
Vol 16 (2) ◽  
pp. 206 ◽  
Author(s):  
M.C. Berg ◽  
A.J. Peterson
Keyword(s):  
New Zealand ◽  
Embryo Transfer ◽  
Body Condition Score ◽  
Pilot Trial ◽  
Beef Cows ◽  
Data Set ◽  
Transfer Programs ◽  
Wide Range ◽  
Condition Score ◽  
Cattle Breeders

Commercial bovine IVP is being extended into new markets and regions worldwide. This study presents pregnancy results from 457 OPU (n=2860 oocytes) sessions performed on a range of commercial donors (n=43) collected twice weekly during a 6-month period in 2002 at a central donor facility. A SOF-culture system was utilized to produce blastocysts (n=750, 1.6/session) for either fresh or frozen-thaw transfer into a wide range of recipient cattle on three sites. Cattle were synchronised with prostaglandin, were observed for behavioural estrus and were eligible to receive an embryo 7 days later. All OPU and embryo transfer were done by a single technician, and pregnancies were confirmed by ultrasound examination at 35 days of gestation. The following table summarizes early pregnancy results from 556 transferred embryos. Recipient selection remains a critical variable as shown in this pilot trial data set. New Zealand’s seasonal calving meant the lactating beef cattle were approximately 60 days postpartum at the start of the embryo transfer programs and the lactating dairy cows were 80 days postpartum. Postpartum interval and body condition score could be interesting variables to elucidate. Bulls were run with the beef cows shortly after embryo transfer resulting in 68% pregnancy rate of those cows whose embryos failed and then were naturally mated. Despite the disappointing results with the lactating beef cows, the overall results have led to OPU/IVP being commercially offered in this new market. The authors would like to acknowledge the ArTech IVP team and the enthusiastic cattle breeders of New Zealand.

The effect of time of mating on ovulation rate and potential lambing rate of Greyface ewes

1979 ◽  
Vol 29 (2) ◽  
pp. 277-282 ◽  
Author(s):  
R. G. Gunn ◽  
J. M. Doney ◽  
W. F. Smith
Keyword(s):  
Body Condition ◽  
Body Condition Score ◽  
Ovulation Rate ◽  
Stress Factors ◽  
Corpora Lutea ◽  
Differential Group ◽  
Condition Score ◽  
Group Feeding ◽  
Lambing Rate

ABSTRACTOver 2 years, 104 Greyface ewes were mated at a synchronized oestrus either in early October or early November. From late September until slaughter at return to service or between 4 and 7 weeks after mating, ewes were fed to maintain their body condition score as previously adjusted by differential group feeding on grass. Ovulation rate and potential lambing rate were derived from counts of corpora lutea and viable embryos at slaughter. Both rates were higher in the early-mated ewes in comparable body condition. Stress factors were implicated as contributing to the decline in ovulation rate with time, while ewes which failed to hold to first mating were largely responsible for the decline in potential lambing rate.

scholarly journals 158 Provision of artificial shade before weaning influences performance of Angus and Brangus cow-calf pairs

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 129-130
Author(s):  
Gleise Medeiros da Silva ◽  
Tessa M Schulmeister ◽  
Federico Podversich ◽  
Federico Tarnonsky ◽  
Maria E Zamora ◽  
...  
Keyword(s):  
Body Condition Score ◽  
Average Daily Gain ◽  
Beef Cows ◽  
Paspalum Notatum ◽  
Gestation Length ◽  
Long Term Effects ◽  
Weaning Weight ◽  
Randomized Design ◽  
Condition Score ◽  
The Impact

Abstract A completely randomized design study with a 2 × 2 factorial arrangement of treatments evaluated the impact of artificial shade (SHADE or NO SHADE) and breed (ANGUS vs. BRANGUS) on performance of cows, nursing calves, and subsequent offspring. Twenty-four Angus and 24 Brangus black-hided pregnant cows (579 ± 8 kg BW; 6.5 yr; approximately 85 d of gestation) and their nursing calves were randomly allocated to 12 ‘Pensacola’ bahiagrass pastures (Paspalum notatum Flüggé; 1.3 ha; n = 4 pairs/pasture), with or without access to artificial shade (NO SHADE BRANGUS [NSB], NO SHADE ANGUS [NSA], SHADE BRANGUS [SB], and SHADE ANGUS [SA]) for 56 d during summer. Body condition score (BCS) of cows and BW of pairs were obtained on d -1, 0, 55, and 56 (weaning weight). Following weaning, calves were randomly allocated to 4 pens (n = 12/pen) equipped with GrowSafe feed bunks for 14 d to measure feed intake (DMI) and efficiency (G:F). A shade × breed interaction (P &lt; 0.05) was observed for average daily gain (ADG) and BCS of cows, with SB being greatest (P ≤ 0.05). Pre-weaning calf ADG tended to be greater (P = 0.10) for SHADE vs. NO SHADE. Weaning weight and BW 14-d post-weaning were lesser for NSB vs. NSA, SA, and SB, whereas no differences in DMI, ADG, or G:F were observed (P &gt; 0.11). Gestation length was greater for SHADE vs. NO SHADE cows (292 vs. 274; P = 0.02), but calf birth weight was not different. Providing artificial shade to pregnant-lactating beef cows positively impacted the growth of Brangus but not Angus cows. However, weaning BW of calves from Angus cows regardless of shade access did not differ from that of Brangus calves with shade. Further research should investigate the potential long-term effects of shade on the subsequent offspring.

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