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      Reproductive parameters of Sindhi cows (Bos taurus indicus) treated with two ovulation synchronization protocols

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          Abstract

          The objective of this study was to evaluate the reproductive parameters of Sindhi cows aiming to improve the efficiency of fixed-time artificial insemination protocols in this breed. For this purpose, sixteen Sindhi cows were divided into two groups: in group I (EB, n = 8) animals received an intravaginal P4 implant and an application of 2 mg of estradiol benzoate on day 0. On day 8 the implant was removed and 10 mg of Dinoprost were applied; on day 9, 1 mg of estradiol benzoate was applied, and animals were fixed-time artificially inseminated 36 hours later; in group II (EB + eCG, n = 8) animals were subjected to same treatment, and on day eight 400 IU of eCG were applied. From day 0 animals were examined daily by a trans-rectal ultrasound device, where in each assessment the largest follicles of each day were measured. The reproductive parameters observed for groups I and II were: emergence of follicular wave, 4.5±1.4 and 3.8±0.3 days; interval between wave emergence and ovulation, 5.8±1.4 and 7.1±0.3 days; interval between wave emergence and implant removal, 3.5±1.4 and 4.1±0.3 days; interval between implant removal and ovulation, 74.0±11.8 and 82.5±4.2 hours; diameter of the dominant follicle (DF) at the time of implant removal, 7.5±2.5 and 6.6±1.5 mm; maximum diameter of DF, 10.47±8.85 and 3.7±1.2 mm; growth rate of DF, 0.90±0.83 and 0.7±0.6 mm/day; ovulation rate, 75% and 100%; and pregnancy rate, 0% and 50%, respectively. There was no significant difference between the groups. We observed that eCG was not efficient in improving the reproductive parameters analyzed in this breed.

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          Most cited references28

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          Regulation of ovarian follicular dynamics in farm animals. Implications for manipulation of reproduction.

          In this review, the main features of folliculogenesis are summarized and compared among species. In the past few years, ultrasonography has clarified follicle growth patterns, and our understanding of follicle maturation has improved considerably. As the follicles develop towards the ovulatory stage, three features appear to be highly conserved across all species: 1) the sequence of events (recruitment, selection and dominance); 2) the sequential need for gonadotropins (FSH for recruitment, LH for dominance) and 3) the large variability of numerical parameters (number of waves per cycle, number of follicles per wave) as well as temporal requirements (time of selection, duration of dominance). In addition, specific follicles may also have variable gonadotropin requirements (thresholds). When patterns of follicle development at different physiological states are compared across species, follicular waves were detected in cattle, sheep and horses and during the prepubertal period in swine, suggesting that ovaries of all species operate on a wave basis unless they are prevented from doing so. Efficient estrus control treatments should have the ability to affect 1) the wave pattern by preventing the development of persistent dominant follicles containing aging oocytes, and 2) the recruitment of the future ovulatory follicle whatever the stage of the wave at the time of treatment. This would allow synchronous ovulation of a growing dominant follicle. Manipulation of the luteal phase follicular waves after mating or AI may also optimize fertility. Superovulation is still an efficient technique to obtain progeny from genetically valuable females. Administration of exogenous gonadotropins acts to reveal the underlying ovarian variability. Ovarian response of each female depends on the number of gonado-sensitive follicles present at the time when treatment is initiated. Identification of the number of such follicles for each female would improve efficacy of superovulation, by allocating potential nonresponders to other techniques (OPU/FIV). One of the main components of the within female response to superovulation is the stage of the wave when gonadotropins are injected. Treatment in the absence of a dominant follicle ensures a response close to the female's specific maximum. The development of practical approaches to achieve this still requires further research.
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            Equine chorionic gonadotropin and gonadotropin-releasing hormone enhance fertility in a norgestomet- based, timed artificial insemination protocol in suckled Nelore (Bos indicus) cows

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              Pregnancy rates in lactating beef cows treated with progesterone releasing devices, estradiol benzoate an equine chorionic gonadotropin (eCG)

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                Author and article information

                Contributors
                Role: ND
                Role: ND
                Role: ND
                Role: ND
                Role: ND
                Role: ND
                Role: ND
                Role: ND
                Journal
                rbz
                Revista Brasileira de Zootecnia
                R. Bras. Zootec.
                Sociedade Brasileira de Zootecnia (Viçosa )
                1806-9290
                June 2013
                : 42
                : 6
                : 414-420
                Affiliations
                [1 ] Universidade Federal Rural do Rio de Janeiro Brazil
                [2 ] Universidade Federal Rural do Rio de Janeiro Brazil
                Article
                S1516-35982013000600005
                10.1590/S1516-35982013000600005
                603f6e72-f9b3-475d-a5aa-24a7c18260e9

                http://creativecommons.org/licenses/by/4.0/

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                SciELO Brazil

                Self URI (journal page): http://www.scielo.br/scielo.php?script=sci_serial&pid=1516-3598&lng=en
                Categories
                AGRICULTURE, DAIRY & ANIMAL SCIENCE
                VETERINARY SCIENCES

                Animal agriculture,General veterinary medicine
                eCG,follicular growth,reproduction,zebu
                Animal agriculture, General veterinary medicine
                eCG, follicular growth, reproduction, zebu

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