Effect of the ovulatory follicle diameter and progesterone concentration on the pregnancy rate of fixed-time inseminated lactating beef cows

The objective of this trial was to evaluate different post-timed artificial insemination (TAI) reproductive managements in postpartum beef cows to produce crossbred calves from artificial insemination (AI). Nellore cows (n = 607), with 45 days postpartum, were inseminated at a fixed time, using a protocol that included an intravaginal progesterone-releasing device along with oestradiol benzoate, prostaglandin, equine chorionic gonadotropin, and oestradiol cypionate, followed TAI 48 h post-device removal. Four post-TAI treatments were evaluated: in CONTROL (T1, n = 161), cows were exposed to Nellore clean-up bulls until the end of the breeding season (75 days). In OBSERVATION (T2, n = 132), heat detection was performed for 15–25 days post-TAI, followed by AI. In RESYNC22 (T3, n = 157) and RESYNC30 (T4, n = 157), resynchronisation started after 22 or 30 days, following second TAI at Day 32 or 40 days after first TAI. In T2, T3 and T4, after the second AI, cows were exposed to Nellore clean-up bulls until the end of the breeding season (75 days). The pregnancy rate (PR) for the first TAI did not differ (54.6%, 53.0%, 59.2%, and 51.6% for CONTROL, OBSERVATION, RESYNC 22, and RESYNC 30, respectively; P = 0.66), and no difference was observed for the second TAI (RESYNC 22 = 45.31% and RESYNC30 = 46.05%; P = 0.137), in the PR at the end of the breeding season (86.33%, 86.36%, 78.98%, and 81.52%, P = 0.43), or embryonic losses (4.54%, 2.85%, 6.45% and 7.40%, respectively; P = 0.61), but the percentage of crossbred pregnancy was higher in groups with resynchronisation (RESYNC22 and RESYNC30) than CONTROL and OBSERVATION (98.38%, 90.62%, 63.30%, 78.95%, P < 0.001). In conclusion, resynchronisation programs of 22 or 30 days are more efficient to produce AI products, and the final pregnancy rate is similar among the treatments, differing only in the amount of calves produced by AI.

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Comparison of the effects of Presynch-Ovsynch, Presynch- Ovsynch+CIDR, and G6G protocols on the reproductive performance of lactating Holstein cows in the postpartum period

Veterinarska stanica ◽

10.46419/vs.53.4.6 ◽

2021 ◽

Vol 53 (4) ◽

Author(s):

Hesam Kohsari ◽

Khatereh Berenjian

Keyword(s):

Serum Concentration ◽

Pregnancy Rate ◽

Reproductive Performance ◽

Body Condition Score ◽

Dairy Farm ◽

Fixed Time ◽

Pregnancy Rates ◽

Holstein Cows ◽

Treatment Protocols ◽

Ovulatory Follicle

This study was performed on an industrial dairy farm near Tehran province, Iran, on 666 lactating Holstein cows from September 2019 to June 2020 in order to eliminate the harmful effects of heat stress on the reproductive performance of the cows. The hypothesis of the recent study was that by increasing the serum concentration of progesterone (P4) in the luteal phase before insemination in the form of Presynch-Ovsynch+CIDR (POC) and G6G protocols, the pregnancy rate of cows would be increased compared to the Presynch-Ovsynch (PO) protocol. The aim of the present study was to evaluate the effects of Presynch-Ovsynch (PGF2α-14d- PGF2α-12d-Ovsynch (OVS: GnRH(GnRH1)- 7d-PGF2α(PG)-2d-GnRH)-18h-Fixed-time artificial insemination (FTAI), n=212), Presynch-Ovsynch+CIDR (similar to the PO protocol, plus the use of a CIDR for 7 days, from the start of the OVS+FTAI protocol to the time of PG injection, n=230), and G6G (PGF2α- 2d-GnRH-6d-OVS+FTAI, n=224) protocols on the reproductive performance and pregnancy rate of lactating Holstein cows. The average body condition score (BCS) for the cows was about 2.5 at the time of the onset of the OVS+FTAI program. The average daily milk production for cows at the time of the start of the OVS+FTAI program was 38.3 kg/day. On average, the studied cows were inseminated 86 days postpartum. Implementation of the G6G protocol in comparison to the PO and POC protocols increased the serum concentration of P4 at GnRH1 (P=0.04). The cows that received the G6G protocol had a greater number of corpuses luteum (CL) on their ovaries at PG in comparison to the cows in the PO and POC protocols (P=0.03 and P=0.05, respectively). For all treatment protocols, the pregnancy rate of cows with >2 CLs on their ovaries at PG was significantly higher than for cows with ≤2 CLs on their ovaries at this time. The overall pregnancy rate for all cows studied was 42%. Separately, pregnancy rates for cows in PO, POC, and G6G protocols were calculated at 36.7%, 41.7%, and 47.3% respectively. The highest and the lowest pregnancy rates were obtained in the G6G and PO protocols, respectively (P=0.03). It can be concluded that the G6G protocol increased the pregnancy rate of cows in comparison to the PO but not to the POC protocol. This result can be attributed to the increase in serum concentration of P4 at GnRH1 and the greater number of CLs at PG following implementation of the G6G compared to the PO protocol. Although CIDR administration in the POC protocol led to an increase in the pregnancy rate of cows compared to the PO protocol, possibly by increasing the synchrony rate and the quality of the ovulatory follicle, this increase was not statistically significant (P=0.09).

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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

Reproduction Fertility and Development ◽

10.1071/rdv26n1ab10 ◽

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.

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Effect of 1 or 2 norgestomet implants inserted from days 15 to 25 after oestrus on follicular development in beef cows

Proceedings of the British Society of Animal Science ◽

10.1017/s0308229600031007 ◽

1996 ◽

Vol 1996 ◽

pp. 133-133

Author(s):

D.A. Adikpe ◽

M.J. Bryant

Keyword(s):

Pregnancy Rate ◽

False Positive ◽

Luteal Phase ◽

Follicular Development ◽

Beef Cows ◽

Beef Heifers ◽

Follicular Wave ◽

Ovulatory Follicle

Controlling the timing of ovulation in cows that fail to conceive after insemination would provide a further opportunity for scheduled rebreeding in a group of cows to save time and optimise results. The ear implant Crestar containing the synthetic progestagen norgestomet provides a means of achieving this control (Sinclair et al., 1992; Lowman et al., 1994). Removing the implant on day 25 after oestrus results in less false positive pregnancy diagnoses than removal on day 21 with the implant in place for nine/ten days. However, treatment of beef heifers with a norgestomet implant towards the end of luteal phase to control oestrus and ovulation is associated with development of a persistent ovulatory follicle and reduced pregnancy rate (Mihm et al., 1994). The objective of this study was to determine the effects of treating beef cows with one or two norgestomet implants on the development of the dominant ovulatory follicle of the second follicular wave.

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Fixed-time AI pregnancy rate following insemination with frozen-thawed or fresh-extended semen in progesterone supplemented CO-Synch protocol in beef cows

Theriogenology ◽

10.1016/j.theriogenology.2008.12.009 ◽

2009 ◽

Vol 71 (7) ◽

pp. 1180-1185 ◽

Cited By ~ 16

Author(s):

A. Bucher ◽

R. Kasimanickam ◽

J.B. Hall ◽

J.M. DeJarnette ◽

W.D. Whittier ◽

...

Keyword(s):

Pregnancy Rate ◽

Fixed Time ◽

Beef Cows

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181COMPARISON OF THE PREGNANCY RATES AFTER SYNCHRONIZATION OF OVULATION USING GnRH AND PGF2± IN RECIPIENT DAIRY CATTLE

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab181 ◽

2004 ◽

Vol 16 (2) ◽

pp. 212 ◽

Cited By ~ 3

Author(s):

T. Nishisouzu ◽

M. Sugawara ◽

S. Aoki ◽

K. Kishida ◽

M. Moriyoshi ◽

...

Keyword(s):

Dairy Cattle ◽

Pregnancy Rate ◽

Embryo Transfer ◽

Fixed Time ◽

Pregnancy Rates ◽

Control Group ◽

Corpora Lutea ◽

Transfer Program ◽

Chi Square ◽

Follicle Diameter

Treatments with GnRH and PGF2α for synchronization of ovulation has resulted in acceptable pregnancy rates after fixed-time artificial insemination in dairy cows without estrus detection. The objective of the present study was to evaluate the practicability of ovulation synchronization (Ovsynch, Pursley JR et al. 1995 Theriogenology 44, 915–923) in dairy cattle using GnRH and PGF2α for the embryo transfer recipients. Dairy cattle (cows; n=100, heifers; n=88) were randomly allocated to one of two groups. The control group (cows; n=45, heifers; n=37) was composed of cows in natural estrus. The ovulation synchronization group (cows; n=55, heifers; n=51) was treated with an intramuscular injection of 100μg of GnRH at a random stage of the estrous cycle. Seven days later, the cattle received PGF2α (Cows; 25–30mg) or PGF2α analog (Heifers; 0.5mg) in order to regress the corpora lutea (CL). Forty-eight hours later, cows and heifers received a second injection of 100μg GnRH. Embryo transfer was carried out 7 days after the second injection of GnRH in the ovsynch group and 7 days after estrus in the control group. The cattle judged to have CL 17mm were classified as acceptable recipients. The size of the follicles and the CL were determined to be of estrus stage and embryo transfer by means of ultrasonography. The mean numbers of follicles and CL were analyzed by ANOVA, while pregnancy rates were analyzed by chi-square test. The results are presented in the Table. The proportion of cows and heifers determined to be acceptable embryo transfers was not different between the control group and the ovsynch group. There were no differences in the proportion of acceptable embryo transfers between the control group and the ovsynch group. Follicle diameter at the time of estrus in the control group (cows; 20.7±0.7mm, heifers; 16.8±0.5mm) were significantly larger than that of the ovsynch group (cows; 18.0±1.0mm, heifers; 14.7±0.2mm) (P<0.05). Although CL diameter at the time of embryo transfer in heifers showed no differences between the control group and the ovsynch group (25.0±1.0mm v. 22.8±1.5mm), The CL diameter of the control cow group was larger than that of the ovsynch group (29.8±0.7mm v. 26.1±1.0mm, P<0.05). However, no differences in pregnancy rate were seen between the control group and the ovsynch group. These results suggest that ovsynch can be effectively applied in an embryo transfer program for cattle. Table 1 Proportion of acceptable embryo transfer recipients and pregnancy rate in dairy cattle in the control ovsynch groups

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156 Injectable trace mineral supplementation on grazing beef cows: effect on overall mineral status and fertility

Journal of Animal Science ◽

10.1093/jas/skaa278.213 ◽

2020 ◽

Vol 98 (Supplement_4) ◽

pp. 117-117

Author(s):

Stefania Pancini ◽

John Currin ◽

Jamie L Stewart ◽

Sherrie Clark ◽

Tracey Redifer ◽

...

Keyword(s):

Pregnancy Rate ◽

Body Condition Score ◽

Post Partum ◽

Fixed Time ◽

Beef Cows ◽

Negative Control ◽

Trace Mineral ◽

Mineral Status ◽

Beef Cow ◽

Estrus Detection

Abstract The objective of this study was to evaluate the effect of two doses of an injectable multi-mineral complex supplementation on beef cow fertility and overall mineral status. A total of 986 Angus crossbred multiparous cows at 8 locations in Virginia were enrolled in a 7-day CO-Synch+CIDR fixed-time artificial insemination (FTAI) protocol, followed by natural service for an approximately 70 d breeding season. All cows had ad libitum access to water, mineral blocks, and diet composed of hay, grass, sudangrass, sorghum grain and commodity pellets, depending on location. Approximately 30 days before calving (d -120, day of AI is d 0) cows were randomly assigned to one of two treatments: 1) Two doses (6 mL) of Multimin® 90 (Multimin USA, Ft. Collins, CO) at d -120 and d -10 (MIN; n = 494); or 2) a negative control with no trace mineral injection (CTRL; n = 492). Body condition score was recorded on d -10, 60 and 120. Estrus detection was recorded at d 0 using estrus detection patches. Pregnancy was diagnosed on d 60 and 120 by ultrasonography. Liver biopsies were collected on d -10 and 60 in a subgroup of 60 cows equally distributed between treatments and among all locations. No differences between treatments were detected in days post-partum (P = 0.66), BCS (P = 0.24) and estrus expression (P = 0.11). Mineral status of copper, manganese, selenium or zinc was similar between treatments before (P = 0.20) and after treatment (P = 0.17). No effect of treatment was detected in FTAI pregnancy rate (50.8%, P = 0.52) or overall pregnancy rate (89.6%, P = 0.64). Two doses of injectable trace mineral administrated approximately 30 days before calving and 10 days before FTAI did not improve pregnancy rate or overall mineral status in multiparous beef cows in Virginia.

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147 EFFECT OF OVULATORY FOLLICLE DIAMETER ON THE OOCYTE TRANSCRIPTOME IN BEEF COWS

Reproduction Fertility and Development ◽

10.1071/rdv28n2ab147 ◽

2016 ◽

Vol 28 (2) ◽

pp. 203

Author(s):

S. E. Dickinson ◽

J. A. Green ◽

T. W. Geary ◽

K. G. Pohler ◽

G. A. Bridges ◽

...

Keyword(s):

Zinc Finger ◽

Zinc Finger Protein ◽

Transcript Abundance ◽

Beef Cows ◽

Fetal Mortality ◽

Physiological Status ◽

Oocyte Competence ◽

Follicle Diameter ◽

Ovulatory Follicle ◽

Prostaglandin F

Inadequate oocyte competence is a potential explanation for reduced pregnancy rates and(or) embryonic/fetal mortality when small dominant follicles are induced to ovulate prematurely with gonadotropin releasing hormone (GnRH). Our hypothesis was that the physiological status of an ovulatory follicle has a direct effect on competence of the oocyte and resulting embryo. The objective was to determine if the transcriptome of oocytes differ depending on whether they are collected from small or large dominant follicles following a GnRH-induced gonadotropin surge. Suckled beef cows (n = 350) were pre-synchronized with a 5-day CIDR protocol. Following pre-synchronization, GnRH1 was administered on Day –9, prostaglandin F on Day –2, GnRH2 (to initiate the ovulatory process) on Day 0, and dominant follicles were transvaginally aspirated on Day 1 before follicular rupture. On Day 0, cows were divided into small (<11.7 mm; no oestrus expression), or large (>12.5 mm; no oestrus expression) groups based on dominant follicle diameter. Oocytes were individually collected after aspiration, and RNA was later extracted from pools of 4 oocytes (n = 6 oocyte pools from both small and large follicles) and sequenced on an Illumina HiSEqn 2000 (single reads, 100 bases; Illumina Inc., San Diego, CA, USA). The sequences were tiled against a ~23 500 member bovine transcript reference obtained from the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/). Tiling to target transcripts required a minimum match of 50 bases with at least 96% identity. Tiling counts were displayed as reads per kilobase of transcript per million mapped reads (RPKM) values, which were obtained by correcting for the length of each target (in kb) and the number of total tiled reads (in millions). Differences between groups were defined by two-tailed t-test and gene lists were selected based on P-values <0.02. Numerous differences in transcript abundance were characterised between oocytes from small and large dominant follicles. Follistatin-like 5 expression was increased (P < 0.02) in oocytes collected from large dominant follicles compared with oocytes collected from small dominant follicles. Several genes were associated with the ubiquitin pathway (e.g. ubiquitin conjugating enzyme, ubiquitin like protein-7) and were up-regulated (P < 0.02) in oocytes from large versus small dominant follicles. In addition, 4 members of the zinc finger protein family were up-regulated (P < 0.02) and 4 members were down-regulated (P < 0.02) in oocytes from large compared with small dominant follicles. In summary, some of the genes that were highly differentially regulated in bovine oocytes between small and large dominant follicles included members of the zinc finger and ubiquitin pathways, which may reflect differences in transcriptional regulation and protein turnover, respectively, between oocytes collected from large and small follicles. Study was supported by AFRI Grant no. 2013–67015–21076 from the USDA National Institute of Food and Agriculture (Washington, DC).

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12 OVARIAN STRUCTURES, ESTRUS EXPRESSION, AND PREGNANCY RATE IN BEEF HEIFERS USING ESTRADIOL CYPIONATE OR GnRH AS OVULATION INDUCTORS IN TIMED AI PROTOCOL

Reproduction Fertility and Development ◽

10.1071/rdv29n1ab12 ◽

2017 ◽

Vol 29 (1) ◽

pp. 113 ◽

Cited By ~ 2

Author(s):

E. Pradebon da Silva ◽

A. B. Machado ◽

L. S. Gambin ◽

A. V. Gonsioroski ◽

M. da Silva ◽

...

Keyword(s):

Pregnancy Rate ◽

Body Condition Score ◽

Device Removal ◽

Treatment Groups ◽

Follicle Diameter ◽

Ovulatory Follicle ◽

Condition Score ◽

In The Beginning ◽

Angus Heifers ◽

Intravaginal Device

The aim of this study was to evaluate the effect of presence of corpus luteum (CL) at the onset of timed AI (TAI) protocol, size of ovulatory follicle and oestrus expression on pregnancy rate using E2 cypionate (EC) or GnRH as ovulation inductor in Angus heifers. On day 0, heifers [n = 414; 317 ± 23 kg; 3.08 ± 0.21 body condition score (1 to 5 scale) and 22–24 months of age] received a 1-g progesterone intravaginal device (Primer®, Agener União, Brazil) and 2 mg of oestradiol benzoate, IM, (RIC-BE®, Agener União, Brazil). On day 8, the device was removed, were administered 500 μg of sodium cloprostenol, IM, (Estron®, Agener União, Brazil) and heifers were divided in 2 groups: EC [n = 213; 0.5mg EC, IM, (SincroCP®, Ouro Fino, Brazil) on day 8] and GnRH [n = 201; 25 μg of Licerelin, IM, (GestranPlus®, Agener União, Brazil) at TAI] TAI was performed 50 h after device removal. Heifers were tail painted (Tell Tail®, GEA, New Zealand) to control oestrus expression from device removal to TAI. Heifers were scanned (7.5-MHz linear transducer MediSono® P3V, USA) to determine presence of CL (Day 0), ovulatory follicle diameter (OFD; Day 10) and ovulation (Day 11). Pregnancy was diagnosed 30 days after TAI. Oestrus expression was confirmed when marking ink was removed on day 10. Data were analysed using logistic regression and ANOVA. Oestrus expression was higher (P < 0.05) in EC (93.90%, 200/213) compared to GnRH group (67.66%, 136/201). The OFD differed (P < 0.05) according to presence of CL on Day 0 (10.3 mm) or not (9.6 mm), but was similar in treatment groups. Ovulation rate did not differ in EC (85%, 17/20) and GnRH (95%, 19/20) groups. Pregnancy rates were similar (P > 0.05) between EC (52.58%, 112/213) and GnRH (59.20%, 119/201) groups; however, in heifers that expressed oestrus, rates were higher (P < 0.05) (EC = 56%, 112/200; GnRH = 71.3%, 97/136) than in those did not show (EC = 0%, 0/13; GnRH = 33.8%, 22/65). Presence of CL at onset of TAI protocol was associated with higher pregnancy (P < 0.05) in GnRH group (68%, 68/100) compared with EC (54.46%, 61/112) group, but in heifers without CL, pregnancy were similar for GnRH (50.5%, 51/101) and EC (50.5%, 51/101) groups. Heifers were also classified in 3 groups according OFD: small (≤9.5 mm), medium (9.6–11.5 mm), and large (≥11.6 mm) to verify its effect on oestrus expression and pregnancy. Medium and large OFD were implicated in higher (P < 0.05) oestrus expression [(EC = 100%, 51/51; 96.97%, 32/33) and (GnRH = 83.02%, 44/53; 97.44%, 38/39)] than small OFD [(EC = 85%, 51/60) and (GnRH = 23.8%, 15/63)]. Pregnancy was lower (P < 0.05) in small OFD groups (EC = 28.3%, 17/60; GnRH = 25.4%, 16/63). In medium and large OFD, pregnancy was similar in EC (72.55%, 37/51; 54.55%, 18/33) groups, but differed (P < 0.05) between GnRH large (82.05%, 32/39) and medium (62.26%, 33/53). Higher pregnancy was achieved in heifers with CL in the beginning of TAI protocol treated with GnRH. Size of ovulatory follicle was associated with higher oestrus behaviour and pregnancy rate in EC and GnRH treatments.

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