PSI-7 Comparison of 6-day versus 7-day CIDR protocol with GnRH and PGFα to synchronize crossbred beef cows for fixed-timed ai with sexed semen at two different times

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 281-282
Author(s):  
Nicole N Noga ◽  
Jeremy G Powell ◽  
Brittni P Littlejohn ◽  
Whitney L Rook ◽  
Martin Mussard ◽  
...  
Keyword(s):  
Fixed Effects ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Chi Square ◽  
Treatment Groups ◽  
Conception Rates ◽  
Sexed Semen ◽  
Chi Square Analysis

Abstract Preliminary data indicate that shortening the progesterone exposure with CIDR can improve conception rates compared to the established 7-day CO-Synch protocols. The objective was to determine the effects of shortening progesterone exposure from 7 days to 6 days among crossbred beef cows and fixed-time artificial insemination (FTAI) with sex-sorted semen. A total of 147 fall calving (September-November) crossbred beef cows from one location were randomized to one of four treatments: 1 and 4) 7-d CO-Synch + CIDR protocol with administration of gonadotropin-releasing hormone (GnRH) and a CIDR insert on day 0, prostaglandin F2α (PGF) at CIDR removal on day 7, and FTAI occurring 66 h (Treatment 1) or 74 h (Treatment 4) later; 2 and 3) 6-d CO-Synch + CIDR protocol with administration of GnRH and CIDR insert on day 0, prostaglandin F2α (PGF) at CIDR removal on day 6, and FTAI occurring 72 h (Treatment 2) or 80 h (Treatment 3) later. Sex-sorted semen from Angus sires was used for AI. Pregnancy was determined by ultrasound 40 days after AI. Pregnancy rate was analyzed using the MIXED procedure of SAS with CIDR and AI service time as fixed effects. Chi-square analysis was used to assess the number of pregnant and open cows in each treatment using the FREQ procedure of SAS. There was no difference (P = 0.78) in pregnancy rates between 6-d CIDR (0.59 ± 0.05%) and 7 d CIDR (0.57 ± 0.05%) protocols. Cattle bred a shorter period after CIDR removal (0.64 ± 0.05%) had numerically (P = 0.11) greater pregnancy rates compared to those with a longer period after CIDR removal (0.51 ± 0.05%). There was no difference in the number of pregnant and open cows between treatment groups. These data suggest that using a 6-day or 7-day protocol, regardless of breeding time, results in similar conception rates.

268 TIMED INSEMINATION OF HEIFERS WITH SEXED SPERM

2008 ◽  
Vol 20 (1) ◽  
pp. 214 ◽  
Author(s):  
J. L. Schenk ◽  
G. E. Seidel
Keyword(s):  
Field Trial ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Labor Costs ◽  
Chi Square ◽  
Chi Square Analysis ◽  
Angus Heifers ◽  
Limited Scope ◽  
Post Onset

The objective of this field trial was to compare pregnancy rates in Angus heifers time-inseminated with sexed sperm 55–56 h or 67–68 h after CIDR removal and administration of 25 mg prostaglandin F2α (PGF2α). Timed insemination eliminates labor costs associated with visual detection of estrus. Anecdotally, use of sexed sperm in commercial timed insemination environments has resulted in reduced pregnancy rates compared to rates for visually observed estrus. However, the optimal fixed time of insemination for sexed sperm has not been studied previously. Sperm were stained at 200 � 106 sperm mL–1 with 49 µm Hoechst 33342 for 45 min at 34.5�C and then diluted to 100 � 106 sperm mL–1 for sorting. Sperm were sexed by flow cytometry/cell sorting at 40 psi using a quasi-cw (pulsed; Vanguard 350-HDM, Spectra-Physics, Mountain View, CA, USA) laser operating at 125 mW, resulting in >91% X-chromosome-bearing sperm. Sorted sperm(2 � 106 total) were packaged into 0.25-mL straws at 10 � 106 sperm mL–1 and cryopreserved. Straws contained >43% progressively motile sperm immediately after thawing for 30 s in a 37�C water bath, as determined by 'track' motility. Angus heifers (n = 67) were synchronized for estrus with IM administration of 100 µg gonadotropin-releasing hormone (GnRH) and a CIDR in place for 7 days, followed by 25 mg PGF2α IM. Heifers were inseminated in the uterine body either 55–56 h (the timing currently recommended for unsexed semen) or 67–68 h after CIDR removal, accompanied by 100 µg GnRH IM, balanced across two inseminators with sperm from two Angus bulls. Estrus was visually detected three times daily but not used as the basis for insemination. Two months post-insemination, pregnancywas determined using ultrasound. Datawere subjected to chi-square analysis. Pregnancy rates for heifers inseminated 55–56 h and 67–68 h after CIDR removal were 34% (n = 11/32) and 46% (n = 16/35), respectively (P > 0.1). Estrus was visually detected for 85% (n = 57/67) of the heifers. Four heifers not detected in estrus became pregnant (40%). Respective pregnancy rates resulting from inseminations 0–12 h and 18–24 h after observed onset of estrus were 25% (7/28) and 55% (16/29), respectively (P < 0.05). Based on the limited scope of this preliminary field trial, insemination of heifers with sexed sperm at 67–68 h post-CIDR removal may be preferable to insemination at 55–56 h. It appears to be best to wait 18 to 24 h post-onset of observed estrus to inseminate heifers with sexed sperm when not using fixed-time insemination procedures. A larger field trial is warranted to more accurately identify the optimal fixed time for insemination using sexed sperm.

scholarly journals 128 Pregnancy and calving rates of beef cows comparing the sex-selected semen to conventional semen using timed artificial insemination

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 1-1
Author(s):  
Jennifer McMurray ◽  
Andrea N DeCarlo ◽  
Nathan Long ◽  
Scott Pratt
Keyword(s):  
Artificial Insemination ◽  
Post Partum ◽  
Statistical Significance ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Chi Square ◽  
Estrous Synchronization ◽  
Beef Cow ◽  
Sexed Semen

Abstract A study was conducted over three years to determine if differences in pregnancy rates existed between the use of commercially available sex-selected (SEXED) or conventional semen (STD) coupled to fixed-time artificial insemination (TAI). A total of 240 (2016: n = 80; 2017: n = 95; 2018: n = 65) primi- or multiparous Angus or Angus-cross cows being at 45 days post-partum or greater were blocked by weight and BCS and assigned to be inseminated using SEXED semen or STD semen. Artificial insemination was performed by the same AI technicians (n = 3) across all years. All cows were subjected to estrous synchronization and insemination using the SEXED semen or STD semen with TAI between 63 and 66 h post-CIDR removal. Fourteen days post-TAI all cows were exposed to bulls for natural service. Cows were subjected to transrectal ultrasonography at day 30 and day 45 post-TAI to determine pregnancy rates and calving dates in the subsequent calving seasons were recorded to determine calving rates to TAI. Pregnancy rates were compared using a Chi-square test of two proportions. All statistical calculations were performed using JMP software and statistical significance was based on p-values less than 0.05. Pregnancy rates at day 30 and day 45 were 39.67% and 48.76% for SEXED and 47.90% and 54.62% for STD, respectively (P &gt; 0.05). The percentage of calves born to TAI pregnancies for sex-selected semen and conventional semen were 22.31% and 40.34%, respectively (P &lt; 0.05). These data indicate that the use of sex-selected semen can give similar pregnancy results to conventional semen in beef cow operations using TAI at day 30 of gestation; however, there was a reduction in the number of offspring to TAI comparing calving dates to animals pregnant at day 30.

Estrous synchronization and fertility of cross-bred dairy cows using prostaglandin F2α and gonadotropin releasing hormone

2021 ◽  
pp. 171-175
Author(s):  
Abubakr O. Ismail ◽  
◽  
Erneo B. Ochi ◽  
Ambrose S. Jubara ◽  
Bakri Ahmed A/Rahim ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Fixed Time ◽  
Gonadotropin Releasing Hormone ◽  
Pregnancy Rates ◽  
Releasing Hormone ◽  
Treatment Groups ◽  
Estrous Synchronization ◽  
Descriptive Statistical Analysis

A comparative hormonal study of prostaglandin, gonadotropin releasing hormone and their combination was conducted on 30 randomly selected cross-bred dairy cows of SEMEX project for artificial insemination in Hillat Kuku, Khartoum North, Sudan. The study attempts to determine the response of the animals to hormonal induction and synchronization of estrous as well as fertility following fixed time artificial insemination. Three treatment groups of 10 cows each were undertaken. Groups 1, 2 and 3 involved administration of prostaglandin F2α (PGF2α), gonadotropin releasing hormone (GnRH) and a combination of PGF2α + GnRH, respectively. Descriptive statistical analysis was performed. The results revealed that all the three protocols induced and synchronized estrous were almost synchronous in all the treated groups. However, protocol 3 revealed a significantly (p<0.05) better result of 70% pregnancy rate compared to other two protocols that equally provided 50% pregnancy rates. The study resolves that protocol 3 be highly recommended to change the mindset of farmers about the spread of reproductive technology in Sudan. Protocols 1 and 2 provided acceptable pregnancy rates that can be enhanced with the improvement of management.

10 INFLUENCE OF ADMINISTRATION OF HUMAN CHORIONIC GONADOTROPIN ON DAY 4 AFTER FIXED-TIME AI ON CORPUS LUTEUM SIZE, FUNCTION, AND PREGNANCY RATE IN BEEF COWS

2014 ◽  
Vol 26 (1) ◽  
pp. 119
Author(s):  
J. B. S. Borges ◽  
D. X. Thedy
Keyword(s):  
Corpus Luteum ◽  
Pregnancy Rate ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Control Group ◽  
Chi Square ◽  
Prostaglandin F2a ◽  
Successful Establishment ◽  
Early Rise

Successful establishment of pregnancy in the cow depends on early rise of progesterone (P4) to improve embryo development. The present study was carried out to determine the corpus luteum (CL) function and pregnancy rate following the administration of 1.500 IU of hCG in suckled beef cows on Day 4 after fixed-time AI (FTAI). Crossbred Angus cows (n = 429), 40 to 70 days postpartum, were synchronized using 2 mg of oestradiol benzoate (EB) i.m. and an intravaginal progesterone-releasing device containing 1 g of P4 for 7 days. At device removal, prostaglandin F2a (150 mg of D-cloprostenol) was injected i.m.; 24 h later, 1 mg of EB was given and the FTAI were done 30 to 36 h after EB using semen of just 1 bull. Cows were assigned alternatively to receive 1.500 IU of hCG i.m. (n = 200) or 1 mL of saline i.m. (n = 229) on Day 4 after FTAI. Ovaries were examined by transrectal ultrasonography (n = 71) on Days 4 and 7 to detect the presence and to measure the area of CL. Blood samples were collected on Days 4, 7, 10, 14, and 30 post-oestrus to determine P4 concentration by RIA. Pregnancy diagnoses were done 30 days after FTAI. The effects of treatments on CL area and serum P4 levels were analysed by ANOVA (Proc GLM, SAS Institute Inc., Cary, NC, USA) and pregnancy rates compared by chi-square (Proc CATMOT, SAS). The induction of accessory CL determined on Day 7 was 44% in cows treated with hCG and not observed in the control group. The area of the CL on Day 7 was significantly higher (P < 0.01; 3.37 ± 2.56 v. 2.56 ± 0.22 cm2) in the hCG group. Despite the increase in CL size, the mean levels of P4 on Days 4, 7, 10, 14, and 30 post-AI indicated no difference (P > 0.05) in CL function between control and hCG-treated cows. On Day 30, pregnancy rates were not different (P = 0.08), at 46.7 and 55% for control and hCG-treated cows, respectively. In conclusion, administration of 1.500 IU of hCG on Day 4 post-FTAI did not improve pregnancy rate in suckled beef cows.

9 EFFECT OF TIMING OF INSEMINATION WITH SORTED SEMEN ON SUBSEQUENT PREGNANCY RATE IN POSTPARTUM BEEF COWS SYNCHRONIZED WITH A MODIFIED 14-DAY PROGESTERONE PROTOCOL

2014 ◽  
Vol 26 (1) ◽  
pp. 119
Author(s):  
A. J. Davis ◽  
J. G. Powell ◽  
T. D. Lester ◽  
R. W. Rorie
Keyword(s):  
Pregnancy Rate ◽  
Animal Health ◽  
Prostaglandin F2α ◽  
Beef Cows ◽  
Subsequent Pregnancy ◽  
Pregnancy Rates ◽  
Treatment Groups ◽  
Rate Analysis ◽  
Chi Squared ◽  
Pregnancy Status

A study investigated the effect of AI timing on pregnancy rate when using X sorted semen, and whether prostaglandin F2α (PGF2) injection on Day 7 of a modified 14-day progesterone (P4) protocol improved oestrous response in beef cows. Angus-based cows were allotted across treatment groups by cyclicity, parity, weight, body condition, and days postpartum. Treatment 1 (n = 132) cows received a CIDR P4 insert (Eazi-Breed CIDR, Pfizer Animal Health, Groton, CT, USA) on Day 0, with CIDR removal on Day 14, followed by 100 μg of gonadotropin-releasing hormone (GnRH; Factrel, Pfizer) on Day 16, and 25 mg of PGF2 (Lutalyse, Pfizer) on Day 23. Treatment 2 (n = 132) cows received the same synchronization treatment, except for an additional 25 mg dose of PGF2 given on Day 7 of CIDR treatment. Cows were observed for oestrus over an 84-h period and inseminated with X-sorted semen at 9 to 14, 15 to 17, 18 to 21 or 22 to 24 h after detected oestrus, followed 10 days later by exposure to fertile bulls for 45 days. Ultrasonography was used to determine pregnancy status ~45 days after AI and again 45 to 55 days after bull removal. Chi-squared analysis was used to determine the effects of treatment on oestrus response, AI pregnancy, and seasonal pregnancy rates, and the effect of AI timing on pregnancy rate. Analysis of variance was used to determine the effects of treatment on the interval from PGF2 dosing to detected oestrus. Oestrus response to synchronization treatment was similar (P = 0.33) at 76.5 and 71.2% for cows in Treatments 1 and 2, respectively. The mean interval from PGF2 to the onset of oestrus was extended (P = 0.03) ~3 h for cows in Treatment 2 (57.4 v. 54.3 h, respectively). About two-thirds of the cows in each treatment were cyclic at the start of synchronization. The extended interval from PGF2 to observed oestrus was due to an effect on cyclic, but not acyclic, cows in Treatment 2. Of the cows expressing oestrus, 69 and 89% expressed oestrus 48 to 72 h post-PGF2 in Treatments 1 and 2, respectively. Pregnancy rates after AI with sorted semen were similar (P = 0.64) at 63.3 and 66.7% for Treatments 1 and 2, respectively. No differences (P = 0.98) were detected in AI pregnancy rates for insemination intervals ranging from 9 to 24 h after detected oestrus. At the end of the breeding season, seasonal pregnancy rates were also similar (P = 0.74), at 83.3 and 84.9% for cows in Treatments 1 and 2, respectively. The addition of a PGF2 treatment on Day 7 of our 14-day CIDR-based protocol was expected to ensure all cows has sub-luteal P4 concentrations and would develop a persistent follicle capable of ovulation in response to GnRH given on Day 16. Whereas the Day 7 PGF2 treatment had no effect on oestrus response or pregnancy rate, it did result in a more synchronous oestrus within a 24-h period. Results indicate that acceptable pregnancy rates can be achieved in lactating beef cows when using sorted semen over a range of insemination times.

19 BEEF CATTLE PREGNANCY RATES FOLLOWING INSEMINATION WITH AGED FROZEN ANGUS SEMEN

2010 ◽  
Vol 22 (1) ◽  
pp. 167 ◽  
Author(s):  
D. B. Carwell ◽  
J. A. Pitchford ◽  
G. T. Gentry Jr ◽  
H. Blackburn ◽  
K. R. Bondioli ◽  
...  
Keyword(s):  
New York ◽  
Animal Health ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Crossbred Cattle ◽  
Chi Square ◽  
Frozen Semen ◽  
Pfizer Animal Health ◽  
Time Periods ◽  
Chi Square Analysis

Artificial insemination has proven to be a valuable asset to the cattle industry. It is assumed that once good quality semen is frozen in liquid nitrogen it should remain viable indefinitely; however, semen viability has not been systematically evaluated after being stored for several decades. In this experiment, frozen semen from 25 purebred Angus bulls processed during 3 time periods (1960-1975 = 5 bulls; 1976-1991 = 11; 1992-2002 = 9 bulls) was used to randomly inseminate purebred lactating Angus cows and heifers and lactating crossbred beef cows. In experiment 1, Angus cows (n = 24) and Angus heifers (n = 16) and in experiment 2, crossbred cattle (n = 88) of 5 breeds (Beefmaster, Romosinuano, Bons Mara, Brangus, Brangus F1) were artificially inseminated with frozen-thawed Angus bulls semen from the 3 time periods. All females were in good body condition and at least 45 days postpartum and were synchronized using the SelectSynch protocol. Briefly, on treatment Day 0, females received an Eazi-Breed CIDR (Pfizer Animal Health, New York, NY, USA) implant and were administered GnRH (Factryl, 100 μg im), on Day 7, prostaglandin (Lutalyse, 25 mg im, Pfizer Animal Health) was administered and the CIDR removed. Cattle not responding to synchronization were subjected an additional prostaglandin treatment 8 to 10 days later. Estrus detection was conducted using the HeatWatch™ system for the Angus females and with Estrotect™ patches for the crossbred females. Females fitted with HeatWatch transponders that were successfully mounted 4 times within a 6-h period were considered to be in standing estrus and were inseminated 12 to 14 h later. Females fitted with Estrotect patches were observed twice daily (morning and evening) to identify females whose patch was scratched. Females were inseminated by an experienced technician 12 to 14h after the patch were observed as being scratched a minimum of 50%. Response to synchronization in Angus cows and heifers was 76% (n = 40), whereas in the crossbred cattle the response was 74% (n = 88). Cows and heifers were confirmed pregnant via transrectal ultrasonography 45 days postinsemination. Pregnancy rates confirmed by chi-square analysis were not different for Angus cows and heifers (58% and 43%, respectively). Also, pregnancy rates for the Angus females were not different across time periods 1, 2, and 3 (58, 43, and 53%, respectively). Pregnancy rates for crossbred females were not different across time periods 1, 2, and 3 (35, 60, and 44%, respectively). Overall pregnancy rates (experiments 1 and 2) were 47, 52, and 40% across time periods 1, 2, and 3 respectively. It is concluded from this study that semen units processed and frozen from Angus bulls from time periods 1, 2, and 3 (from the 1960s through to 2002) are still viable and produce similar pregnancy rates in artificially inseminated beef females. Thanks to Jared Pitchfordfor inseminating all of the cattle; Harvey Blackburn for providing the semen to make the project possible; and my advisors Dr. Gentry and Dr. Godkefor assisting throughout the entire project. I also thank all of the graduate students who have helped me throughout the project.

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

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

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

scholarly journals PSII-29 Effects of delayed injection of prostaglandin F2α and TAI in the 14-d CIDR-PG & TAI protocol in replacement beef heifers

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 375-376
Author(s):  
Nicky Oosthuizen ◽  
Gabriela Melo ◽  
Lawton Stewart ◽  
George Seidel ◽  
Graham Cliff Lamb ◽  
...  
Keyword(s):  
Prostaglandin F2α ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Transrectal Ultrasonography ◽  
Dominant Follicle ◽  
Beef Heifers ◽  
Treatment Groups ◽  
Follicle Diameter ◽  
Randomized Design ◽  
Angus Heifers

Abstract To determine the effects of delaying the injection of prostaglandin F2α (PGF) and fixed-time artificial insemination (TAI) in the 14-d CIDR-PG & TAI protocol, 911 Angus heifers at 5 locations were enrolled in a completely randomized design. Within location heifers were randomly assigned to 1 of 2 treatment groups: 1) PG16 (n = 452), heifers received a CIDR insert on d 0 for 14 d, a 25-mg injection of PGF 16 d after CIDR removal [d 30], and a 100-µg injection of gonadotropin-releasing hormone concurrently with TAI 66 ± 2 h later; or 2) PG17 (n = 459), heifers were treated the same as PG16, however, PGF was administered 17 d after CIDR removal [d 31], and heifers were TAI 66 ± 2 h later. Estrus detection patches were applied to heifers at the time of PGF administration and were examined for activation at TAI. Dominant follicle diameter was determined via transrectal ultrasonography at PGF administration and TAI in a subset of heifers (n = 171). Furthermore, transrectal ultrasonography was performed to determine pregnancy rates to TAI (PR/AI) between 30 and 45 d after TAI. Estrus expression prior to TAI was similar (P = 0.50) between treatments (48.9 vs. 52.0%, respectively). Moreover, dominant follicle diameter at PGF and TAI was similar (P ≥ 0.43) between PG16 and PG17 heifers. Pregnancy rates to TAI did not differ (P = 0.48) between treatment groups (46.4 vs. 48.9%, respectively). The results of this experiment indicate that delaying the injection of PGF from d 30 to d 31 along with TAI in the 14-day CIDR-PG & TAI protocol had no effects on fertility parameters in beef heifers. In conclusion, the PGF injection and TAI in the 14-d CIDR-PG & TAI protocol may be delayed, providing more flexibility in scheduling without negatively affecting fertility.

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

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

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

The use of fixed time artificial insemination programmes for the use of sexed semen in block calving dairy heifers

Livestock ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 124-130
Author(s):  
Mike Kerby ◽  
Tom Clarke ◽  
Tom Angel ◽  
Kythé Mackenzie
Keyword(s):  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Cost Benefit ◽  
Fixed Time ◽  
Reproductive Efficiency ◽  
Costs And Benefits ◽  
Dairy Heifers ◽  
Conception Rates ◽  
Sexed Semen

In seasonal block calving herds reproductive efficiency can have a significant impact on productivity and profitability. Within this it is key that the nulliparous heifers calve down promptly in the block, and if these heifers can have heifer calves it will expediate genetic gain. There is extensive research into the conception rates of differing protocols and the literature is reviewed to support the choice of protocol used in the subsequent case study. The case study uses a 6-day progesterone protocol with two injections of prostaglandin F2α and sexed semen; it demonstrated acceptable conception rates as well as the variability that can occur between different bulls' semen straws. Finally, the case study assesses the costs and benefits of the synchronisation programme and concludes a cost benefit of £88.55 per heifer.

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