Effects of extending the length of pro-oestrus in an oestradiol- and progesterone-based oestrus synchronisation program on ovarian function, uterine environment and pregnancy establishment in beef heifers (original) (raw)
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Animal Reproduction Science, 2020
Estrous response and pregnancy percentages following use of a progesterone-based, split-time estrous synchronization treatment regimens in beef heifers Ramanathan Kasimanickam (Conceptualization) (Resources) (Methodology) (Investigation) (Formal analysis) (Software) (Supervision)ce:contributor-roleWriting-review and Editing) (Funding acquisition), Katriana Jorgensen-Muga (Methodology) (Investigation) (Formal analysis), Janey Beumeler (Methodology) (Investigation) (Formal analysis), Kamron Ratzburg, Aliasgar Kapi (Methodology) (Investigation) (Formal analysis), Vanmathy Kasimanickam (Conceptualization) (Methodology) (Resources) (Investigation) (Formal analysis) (Software) (Writing-review and editing), John Kastelic (Methodology) (Writing-review and editing) PII: S0378-4320(20)30416-4
The Canadian veterinary journal. La revue vétérinaire canadienne, 2007
The objective was to optimize rebreeding of nonpregnant, previously inseminated beef cattle. In Experiment 1, 43 cows received a used intravaginal progesterone-releasing insert (IVPRI; Days 0-7) 12.3 d after ovulation and received concurrently no treatment, 100 microg gonadotropin releasing hormone (GnRH), 1 mg estradiol cypionate (ECP), or 150 mg progesterone. Emergence of a new ovarian follicular wave was most synchronous (P < 0.0001) in the GnRH group. In Experiment 2, 675 heifers were given GnRH or no treatment on Day 0, fed melengestrol acetate (MGA; 0.5 mg/head/d) from Days 0-5 (Day 0 = 13-14 d after timed insemination; TAI), given 0.5 mg ECP or nothing on Day 7, and reinseminated 6-12 h after onset of estrus. Estrus was more synchronous (P < 0.05) in heifers given GnRH versus no treatment on Day 0. In Experiment 3, 317 TAI heifers were resynchronized with either MGA or a used IVPRI with or without ECP on Day 7; estrus was more synchronous (P < 0.05) and pregnancy rat...
Tierarztliche Praxis. Ausgabe G, Grosstiere/Nutztiere, 2016
The aim of this study was to monitor the ovarian response and conception rate following estrous synchronization using CIDR, Ovsynch and double prostaglandin F2α protocols in Egyptian buffalo heifers. A total of 80 cyclic buffalo heifers were divided into four equal groups: CIDR (intravaginal progesterone releasing device, EAZI-BREED(TM) CIDR(®)), Ovsynch (GnRH, PGF2α, GnRH injections), PGF (double PGF2α doses) and control. Timed artificial insemination (TAI) was performed in all heifers. All animals were examined using ultrasound and blood samples were collected for measurement of progesterone. A new follicular wave occurred earlier in the Ovsynch and PGF groups than in the CIDR group (p < 0.05). The mean diameter of the ovulatory follicle was smaller in the CIDR group than in the Ovsynch and PGF groups (p < 0.05). The ovulation rate was 100% in the CIDR group, 75% in the Ovsynch group and 70% in the PGF group. In the control group a lower pregnancy rate (20%) was determined i...
Theriogenology, 2019
An experiment was designed to evaluate the effect of extending duration of the presynchronization treatment in a long-term progestin-based estrus synchronization protocol. Heifers were assigned to either an 18 d (Day 0e18) or 14 d (Day 4 to Day 18) CIDR ® treatment (1.38 g progesterone controlled internal drug release insert; Zoetis, Madison, NJ), with prostaglandin F 2a (PG; 250 mg im cloprostenol sodium) administered 16 d after CIDR ® removal (Day 34). Heifers at two locations (location one, n ¼ 193; location two, n ¼ 649) were assigned to treatment based on reproductive tract score (RTS; Scale 1e5) and body weight. Heifers that were assigned RTS 1 were not retained for the trial (n ¼ 6). Estrus detection aids (Estrotect ®) were applied at PG. Split-time artificial insemination (STAI) was utilized and AI performed based on expression of estrus at 66 h. Expression of estrus was defined as removal of !50% of the grey coating from the Estrotect ® patch. Heifers that expressed estrus at 66 h were inseminated then and heifers that had not expressed estrus were inseminated at 90 h. Only heifers that failed to express estrus by 90 h received gonadotropin-releasing hormone (GnRH; 100 mg im gonadorelin acetate) at the time of AI. At location one, blood samples were collected at PG and AI (66 h or 90 h) from all heifers to determine E 2 concentration by radioimmunoassay, and transrectal ovarian ultrasound was performed to detail ovarian structures on a subset of heifers (n ¼ 73) at both time points. The proportion of heifers expressing estrus did not differ between treatments, either by 66 h (60%) or in total by 90 h (84%) after PG. Pregnancy rate to STAI did not differ between treatments (P ¼ 0.3; 52%, 14-d CIDR ®-PG; 50%, 18-d CIDR ®-PG), or at the end of the 60 d breeding season (P ¼ 0.2; 86%, 14-d CIDR ®-PG; 82%, 18-d CIDR ®-PG). No differences were detected in mean diameter of the dominant follicle at PG (P ¼ 0.6; 10.9 ± 0.4 mm, 14d CIDR ®-PG; 11.0 ± 0.4 mm, 18-d CIDR ®-PG) or at STAI (P ¼ 0.3; 12.6 ± 0.4 mm, 14-d CIDR ®-PG; 13.2 ± 0.4 mm, 18-d CIDR ®-PG), nor were any differences observed between treatments in concentrations of E 2 at PG (P ¼ 0.8; 1.1 ± 0.19 pg/ml, 14-d CIDR ®-PG; 1.1 ± 0.19 pg/ml, 18-d CIDR ®-PG) or STAI (P ¼ 0.6; 3.8 ± 0.19 pg/ml, 14-d CIDR ®-PG; 3.6 ± 0.19 pg/ml, 18-d CIDR ®-PG). These data indicate that duration of CIDR ® treatment can be extended from 14 to 18 d, thus providing flexibility in scheduling without compromising reproductive outcomes.
Reproduction, 1998
The aim of the present study was to develop a treatment protocol for the precise synchronization of oestrus that would avoid the development of persistent dominant ovarian follicles. Bos indicus heifers, in which oestrous cycles had been presynchronized, were allocated randomly, according to the day of their oestrous cycle, to one of five treatment groups. All heifers received a subcutaneous ear implant containing 3 mg of norgestomet for 17 days starting on day 0 and an injection of an analogue of prostaglandin F2\ g=a\ on days 0 and 4. Heifers in group 1 (control group; n = 7) received no other treatment, while heifers in groups 2 (n = 8), 3 (n = 7), 4(n = 7), and 5 (n= 7) received a single progesterone-releasing controlled internal drug release device (CIDR) for 24 h on days 10, 12, 14 and 16, respectively. Treatment with a single CIDR delayed the mean time of ovulation and the day of emergence of the ovulatory follicle in heifers treated on days 14 and 16 compared with control heifers (P<0.05). There was less variation in the interval to ovulation in heifers treated on day 10 compared with other treated heifers (P < 0.05). The variation among heifers in the day of emergence of the ovulatory follicle and the age of the ovulatory follicle at ovulation was less for all groups treated with a CIDR than for the control group (P<0.05). The duration of dominance and variation in the duration of dominance of the ovulatory follicle was less in heifers treated with a CIDR device on days 10 and 16 than for control heifers (P < 0.05). Mean age (days from emergence to ovulation) of the ovulatory follicle did not differ among treatment groups (P > 0.05). Concentrations of LH and oestradiol decreased coincident with increased concentrations of progesterone on the days of CIDR treatment in treated compared with control heifers (P < 0.02) but increased again after removal of the CIDR. A smaller proportion of follicles in the growing phase of follicular development at the time of CIDR treatment become atretic compared with follicles that had reached a plateau phase of follicular growth (14.3% (1/7) versus 90.5% (19/21), respectively; P < 0.001). It was concluded that acute treatment with progesterone can influence the growth pattern of ovarian follicular development. However, the effect varies with the stage of ovarian follicular development. Short term treatment with progesterone 7 days before the end of a 17 day period of norgestomet treatment resulted in precise synchrony of ovulation without the ovulation of a persistent dominant ovarian follicle.
Animal Reproduction Science, 1995
In order to induce suprabasal plasma concentrations of progesterone after luteolysis and to determine their effect on oestrous behaviour and ovulation, heifers subcutaneously received silicone implants containing 2.5 (n = 4), 5 (n = 4), 6 (n = 3), 7.5 (n = 3) or 10 (n = 4) g of progesterone, or an empty implant (controls, n = 5) between days 8 and 25 of the cycle (ovulation designated Day 0). Growth of dominant follicles and time of ovulation were determined by ultrasound, and signs of oestrus were recorded and scored. Blood was collected at 2–4 h intervals from Days 15 to 27 and assayed for progesterone concentration. In all heifers, plasma concentrations of progesterone sharply decreased during Days 16–18. Control heifers had their lowest progesterone levels on Days 20.5 and 21, standing oestrus on Day 19.5 ± 0.4 (mean ± SEM), and ovulated on Day 20.7 ± 0.4. A similar pattern was observed in heifers treated with 2.5 and 5 g progesterone. Heifers treated with 6, 7.5 and 10 g of progesterone showed an extended (P < 0.05) interovulatory interval. Onset of prooestrus and time of maximum expression of signs of oestrus were not significantly different from those in controls. However, there was an absence of standing oestrus in most of the cases, signs of oestrus lasted longer (P < 0.05) and were weaker in intensity when doses increased. In these groups, the lowest progesterone concentrations were attained shortly after implant removal. Some heifers treated with 6 and 7.5 g of progesterone had standing oestrus and post oestrous bleeding as seen in the controls but ovulation occurred from Days 24.5 to 27. When plasma progesterone concentrations were over 1 nmol 1−1, disturbed oestrus and delayed ovulation occurred. The extended period of prooestrus and oestrus and delayed ovulation were similar to that described in cases of repeat breeding. It is suggested that suprabasal plasma concentrations of progesterone, after luteolysis, may lead to asynchrony between onset of oestrus and ovulation and consequently be a cause of repeat breeding in cattle.
Exogenous hormonal manipulation of ovarian activity in cattle
Domestic Animal Endocrinology, 2002
To achieve precise control of the oestrous cycle in cattle it is necessary to control both the life span of the corpus luteum and the follicle wave status at the end of the treatment. Antral follicle growth in cattle occurs in distinct wavelike patterns during the ovarian cycle and the postpartum anoestrous period. The emergence of each new wave is stimulated by a transient increase in FSH. Each follicle wave has an inherent life span of 7-10 days as it progresses through the different stages of development, viz., emergence, selection, dominance and atresia or ovulation. The dominant follicle (DF) is distinguishable from other subordinate follicles by its enhanced capacity to produce oestradiol, maintenance of low intrafollicular concentrations of insulin-like growth factor binding proteins-2,-4 and-5 and follistatin and an increase in free intrafollicular concentrations of IGF-I as well as an increase in size. Three approaches can be taken to control ovarian activity and regulate the oestrous cycle in cattle: (i) use of the luteolytic agent prostaglandin F2␣ (PGF2␣) alone or one of its potent analogues, (ii) administration of exogenous progesterone-progestagen treatments combined with the use of exogenous oestradiol or gonadotrophin releasing hormone (GnRH) to control new follicle wave emergence and shorten the life span of the corpus luteum, and (iii) prior follicle wave synchrony followed by induced luteolysis. A number of different oestrous synchronisation regimens, viz., PGF2␣-based only, short-term progesterone with prior follicle wave synchrony using oestradiol or GnRH have been developed but the problem of obtaining good follicle wave synchrony and CL regression limit their widespread application. GnRH-prostaglandin-GnRH regimens have recently been developed for beef and dairy cows. However, their success is variable. A better understanding of the hormonal control of follicle growth is a prerequisite in order to obtain more precise control the oestrous cycle allowing one AI at a predetermined time giving high pregnancy rates without recourse to detection of oestrus.