The The effect of ketones on estrogen, progesterone, ovulatory follicle size, estrus and fertility in Holstein Cows

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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Inducing ovulation with oestradiol cypionate allows flexibility in the timing of insemination and removes the need for gonadotrophin-releasing hormone in timed AI protocols for dairy cows

Reproduction Fertility and Development ◽

10.1071/rd15270 ◽

2017 ◽

Vol 29 (3) ◽

pp. 468 ◽

Cited By ~ 2

Author(s):

R. M. Ferreira ◽

H. Ayres ◽

L. U. Gimenes ◽

F. P. Torres ◽

F. A. Lima ◽

...

Keyword(s):

Dairy Cows ◽

Pregnancy Rates ◽

Holstein Cows ◽

Device Removal ◽

Releasing Hormone ◽

Ovulatory Follicle ◽

Oestradiol Benzoate ◽

Gonadotrophin Releasing Hormone

The effects of addition of gonadotrophin-releasing hormone (GnRH) to a progesterone plus oestradiol-based protocol and timing of insemination in Holstein cows treated for timed AI (TAI) were evaluated. Cows (n = 481) received a progesterone device and 2 mg oestradiol benzoate. After 8 days, the device was removed and 25 mg dinoprost was administered. Cows were allocated to one of three (Study 1; n = 57) or four (Study 2; n = 424) groups, accordingly to ovulation inducer alone (Study 1; oestradiol cypionate (EC), GnRH or both) or ovulation inducer (EC alone or combined with GnRH) and timing of insemination (48 or 54 h after device removal; Study 2). In Study 1, the diameter of the ovulatory follicle was greater for GnRH than EC. Oestrus and ovulation rates were similar regardless of ovulatory stimuli. However, time to ovulation was delayed when GnRH only was used. In Study 2, cows treated with GnRH or not had similar pregnancy per AI (P/AI) 30 days (41.5% vs 37.3%; P = 0.28) and 60 days (35.9% vs 33.0%; P = 0.61) after TAI. TAI 48 and 54 h after device removal resulted similar P/AI at 30 days (40.3% vs 38.5%; P = 0.63) and 60 days (33.8% vs 35.1%; P = 0.72). Thus, adding GnRH at TAI does not improve pregnancy rates in dairy cows receiving EC. The flexibility of time to insemination enables TAI of a large number of cows using the same protocol and splitting the time of AI.

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Relationship of pre-ovulatory follicle size, estradiol concentrations and season to pregnancy outcome in dairy cows

Animal Reproduction Science ◽

10.1016/j.anireprosci.2006.04.056 ◽

2007 ◽

Vol 99 (1-2) ◽

pp. 34-43 ◽

Cited By ~ 61

Author(s):

A.S. Lopes ◽

S.T. Butler ◽

R.O. Gilbert ◽

W.R. Butler

Keyword(s):

Dairy Cows ◽

Pregnancy Outcome ◽

Ovulatory Follicle ◽

Follicle Size ◽

Relationship Of

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Effect of ovulatory follicle size on bovine pregnancy associated glycoproteins in beef cattle

10.32469/10355/8069 ◽

2010 ◽

Author(s):

Cia L. Johnson

Keyword(s):

Beef Cattle ◽

Ovulatory Follicle ◽

Bovine Pregnancy ◽

Follicle Size

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Determinants of Embryo Development and Quality in Beef Cattle: Effect of Pre-Ovulatory Follicle Size, CL Volume, and Serum Concentrations of Progesterone.

Biology of Reproduction ◽

10.1093/biolreprod/81.s1.505 ◽

2009 ◽

Vol 81 (Suppl_1) ◽

pp. 505-505 ◽

Cited By ~ 1

Author(s):

Jacqueline A. Atkins ◽

Michael F. Smith ◽

Michael D. MacNeil ◽

Thomas W. Geary

Keyword(s):

Beef Cattle ◽

Embryo Development ◽

Serum Concentrations ◽

Ovulatory Follicle ◽

Follicle Size

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Factors influencing reproductive efficiency and pregnancy in Pura Raza Española mares

Veterinární Medicína ◽

10.17221/205/2015-vetmed ◽

2017 ◽

Vol 62 (No. 4) ◽

pp. 186-191

Author(s):

A. Akourki ◽

A. Echegaray ◽

MV Falceto ◽

O. Mitjana

Keyword(s):

Pregnancy Loss ◽

Post Partum ◽

Reproductive Efficiency ◽

Ovarian Activity ◽

Gestation Length ◽

Ovulatory Follicle ◽

Follicle Size ◽

Spss Software ◽

Twin Pregnancies ◽

Length Of Gestation

The aim of this study was to analyse ovarian activity and pregnancy in 140 Pura Raza Espanola mares over a period of two consecutive years. The data were analysed using SPSS software to evaluate the effects of age, category of mares and season on pre-ovulatory follicle size, ovulation rate, interval from foaling to pregnancy, gestation length, incidence of twin pregnancies and pregnancy losses. The results showed that follicular diameter was significantly (P < 0.05) smaller in fillies (3-year-old) and maiden mares than in older and multiparous mares. Within the group of animals treated with gonadotropin hormone hCG, 87.23% ovulated 48 h following administration. Length of gestation varied from 305 to 356 days and all gestation pregnancies of less than 305 days resulted in a non-viable foal. In addition, foaling season affected (P < 0.05) the post-partum conception interval and the length of gestation, which were shorter and longer in the winter foaling, respectively. Regarding the other parameters, mares of this stud exhibited relatively very low rates of double ovulations, twin pregnancies and pregnancy losses. We conclude that age and category of mares and foaling season influence fertility and foaling rates by affecting pre-ovulatory follicle size, pregnancy loss and gestation length.

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Timing of final GnRH of the Ovsynch protocol affects ovulatory follicle size, subsequent luteal function, and fertility in dairy cows

Theriogenology ◽

10.1016/s0093-691x(03)00120-1 ◽

2003 ◽

Vol 60 (6) ◽

pp. 1197-1204 ◽

Cited By ~ 69

Author(s):

M.W. Peters ◽

J.R. Pursley

Keyword(s):

Dairy Cows ◽

Luteal Function ◽

Ovulatory Follicle ◽

Follicle Size

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Analysis of Lacker's Model with an Ageing Factor for the Control of Ovulation and Polycystic Ovary Syndrome

Journal of Theoretical Medicine ◽

10.1080/10273660108833079 ◽

2001 ◽

Vol 3 (4) ◽

pp. 247-270 ◽

Cited By ~ 1

Author(s):

A. Chávez-Ross

Keyword(s):

Polycystic Ovary Syndrome ◽

Deterministic Model ◽

Polycystic Ovary ◽

Selection Process ◽

Local Level ◽

Threshold Level ◽

Ovary Syndrome ◽

Ovulatory Follicle ◽

Follicle Size ◽

Follicle Selection

In the present paper, we develop an extensive theoretical analysis of the deterministic model for the control of ovulation in mammals proposed by Mariana et al., (1994), which is an extension of Lacker's model. Marianaet al.incorporated an age decaying factor in follicle maturity, and kept follicle growth law as Lacker first proposed. However, they produced only some numerical examples simulating the new advantages of their model. As a result of the present analysis, we propose an alternative understanding of folliclegenesis, pre-ovulatory follicle selection in mammals, and polycystic ovary syndrome (PCOS) in women. In particular, a minimum oestradiol threshold level required for initial follicular growth is obtained. Relative values of follicle size and age necessary for its development are also determined. We prove that the model controls pre-ovulatory follicle selection rate at a local level. The model is shown to be globally unstable and fails to regulate the selection process. Finally, a discussion on how these results bring new insight to possible causes for PCOS is given.

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