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Made available in DSpace on 2018-11-26T17:20:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Zoetis Saude Animal (Campinas -SP, Brazil) 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 2mg oestradiol benzoate. After 8 days, the device was removed and 25mg 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 54h 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 54h 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. Univ Sao Paulo, Dept Reprod Anim, Fac Med Vet & Zootecnia, Ave Prof Dr Orlando Marques de Paiva 87, BR-05508270 Sao Paulo, SP, Brazil Univ Sao Paulo, Dept Med Vet, Fac Zootecnia & Engn Alimentos, Ave Duque de Caxias Norte 225,Campus USP, BR-13635900 Pirassununga, SP, Brazil MSD Saude Anim, Ave Nacoes Unidas 14171,Torre C,Crystal Tower, BR-04794000 Sao Paulo, SP, Brazil Univ Estadual Paulista, Dept Med Vet Prevent & Reprod Anim, Fac Ciencias Agr & Vet, Via Acesso Prof Paulo Donato Castellane S-N, BR-14884900 Jaboticabal, SP, Brazil Cent Pioneiros, Ave Pioneiros, BR-84145000 Carambei, PR, Brazil Univ Estadual Paulista, Dept Prod Anim, Fac Med Vet & Zootecnia, Dist Rubiao Jr S-N,Caixa Postal 560, BR-18618970 Botucatu, SP, Brazil Univ Estadual Paulista, Dept Med Vet Prevent & Reprod Anim, Fac Ciencias Agr & Vet, Via Acesso Prof Paulo Donato Castellane S-N, BR-14884900 Jaboticabal, SP, Brazil Univ Estadual Paulista, Dept Prod Anim, Fac Med Vet & Zootecnia, Dist Rubiao Jr S-N,Caixa Postal 560, BR-18618970 Botucatu, SP, Brazil FAPESP: 2009/00938-3 FAPESP: 2012/07510-1 CNPq: 486089/2013-14

Background This study evaluated the impact of hormonal modulation at the onset of proestrus on ovarian response and uterine gene expression of beef cows. Methods A total of 172 anestrous beef cows were assigned to one of four groups according to the treatment with estradiol cypionate (ECP) and/or equine chorionic gonadotropin (eCG) [CON (n = 43), ECP (n = 43), eCG (n = 44) and ECP + eCG (n = 42)]. Results ECP-treated cows (ECP and ECP + eCG groups) presented greater occurrence of estrus (44.6% vs. 65.4%; P = 0.01) and pregnancy per AI [47.1% vs. 33.3%; P = 0.07], but similar progesterone (P4) concentration at subsequent diestrus than cows not treated with ECP (CON and eCG groups). Nonetheless, eCG-treated cows (eCG and ECP + eCG groups) presented larger follicle at timed AI (12.6 ± 0.3 vs. 13.5 ± 0.3 mm; P = 0.03), greater ovulation rate (96.5% vs. 82.6%; P = 0.008) and greater P4 concentration at d 6 (3.9 ± 0.2 vs. 4.8 ± 0.2 ng/mL; P = 0.001) than cows not treated with eCG (CON and ECP groups). Next, cows with a new corpus luteum 6 d after TAI were submitted to uterine biopsy procedure. Uterine fragments [CON (n = 6), ECP (n = 6)] were analyzed by RNA-Seq and a total of 135 transcripts were differentially expressed between groups (73 genes up-regulated by ECP treatment). Subsequently, uterine samples were analyzed by qPCR (genes associated with cell proliferation). ECP treatment induced greater abundance of PTCH2 (P = 0.07) and COL4A1 (P = 0.02), whereas suppressed EGFR (P = 0.09) expression. Conversely, eCG treatment increased abundance of HB-EGF (P = 0.06), ESR2 (P = 0.09), and ITGB3 (P = 0.05), whereas it reduced transcription of ESR1 (P = 0.05). Collectively, supplementation with ECP or eCG at the onset of proestrous of anestrous beef cows influenced ovarian responses, global and specific endometrial gene expression. Conclusion Proestrus estradiol regulate the endometrial transcriptome, particularly stimulating proliferative activity in the endometrium. Electronic supplementary material The online version of this article (10.1186/s40104-017-0211-3) contains supplementary material, which is available to authorized users.

Made available in DSpace on 2018-12-11T17:15:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This study evaluated the effects of differing circulating progesterone (P4) levels on the luteinizing hormone (LH) surge profile following treatment with gonadotropin releasing hormone (GnRH) in B. indicus (Nelore, n = 13) and B. taurus (Holstein, n = 16) heifers. All heifers were synchronized with a hormonal protocol to induce either a Low or High circulating P4 environment at the time of GnRH treatment. Heifers were randomly assigned to a 2 × 2 factorial design composed by two genetic groups (B. indicus and B. taurus) and two levels of circulating P4 concentrations (Low or High). Blood samples were collected every 30 min from −30 to 210 min and at 270 min after GnRH treatment. As expected, mean P4 concentration was greater for cows in the High than in the Low P4 group (P = 0.0008) and in Bos indicus than in Bos taurus heifers (P = 0.06). Despite genetic group, the area under the curve of LH release was greater in the Low-P4 than in High-P4 concentration group (P < 0.0001). Interestingly, it appears that High P4 concentrations had a more pronounced effect on LH peak in B. indicus than in B. taurus heifers, as indicated by the interaction (P = 0.01) between genetic group and P4 levels. In conclusion, circulating P4 concentration have a great impact on the GnRH-induced LH surge of both B. indicus and B. taurus heifers, but it does not explain the much lower LH peak in B. indicus with low circulating P4. Thus, more studies are essential to uncover some of the underlying physiological factors other than circulating P4 that are limiting LH release following a GnRH treatment in B. indicus cattle. Department of Animal Reproduction FMVZ-USP Campus Sao Paulo Department of Animal Production and Nutrition FMVZ-USP Campus Pirassununga Department of Animal Health Production and Support FMVA-UNESP Campus Araçatuba Ceva Animal Health Department of Animal Health Production and Support FMVA-UNESP Campus Araçatuba FAPESP: proc.2012/00889-5

The main objective of the implementation of artificial insemination (AI) in cattle is to produce a sustained genetic progress in the herd. Although AI is an old reproductive biotechnology, its widespread implementation is very recent and is mainly because of the use of protocols that allows AI without oestrus detection, commonly called fixed-time artificial insemination (FTAI). The development of FTAI protocols also allowed the application of AI in larger, extensively managed herds and especially in suckled cows instead of restricting the breeding programmes to the heifers. Fixed-time AI treatments are widely used in South America, with about 3 000 000 cows inseminated in the last season in Argentina and about 8 000 000 in Brazil. The objective of this review is to present and describe the various treatments available and some of the factors that may affect pregnancy rates in beef cattle.

The aim of the present study was to evaluate the effects of the PGF 2 α treatment given at the onset of a synchronization of ovulation protocol using a norgestomet (NORG) ear implant on ovarian follicular dynamics (Experiment 1) and pregnancy per AI ( P /AI; Experiment 2) in cyclic (CL present) Bos indicus heifers. In Experiment 1, a total of 46 heifers were presynchronized using two consecutive doses of PGF 2 α 12 days apart. At first day of the synchronization protocol the heifers received implants containing 3 mg of NORG and 2 mg of estradiol benzoate (EB). At the same time, heifers were randomly assigned to receive 150 mg of d -cloprostenol ( n = 23; PGF 2 α ) or no additional treatment ( n = 23; Control). When the ear implants were removed 8 days later, all heifers received a PGF 2 α treatment and 1 mg of EB was given 24 h later. The follicular diameter and interval to ovulation were determined by transrectal ultrasonography. No effects of PGF 2 α treatment on the diameter of the largest follicle present were observed at implant removal (PGF 2 α = 9.8 ± 0.4 vs. Control = 10.0 ± 0.3 mm; P = 0.73) or after 24 h (PGF 2 α = 11.1 ± 0.4 vs. Control = 11.0 ± 0.4 mm; P = 0.83). No differences in the time of ovulation after ear implant removal (PGF 2 α = 70.8 ± 1.2 vs. Control = 73.3 ± 0.9 h; P = 0.10) or in the ovulation rate (PGF 2 α = 87.0 vs. Control = 82.6%; P = 0.64) between treatments were observed. In Experiment 2, 280 cyclic heifers were synchronized using the same experimental design described above (PGF 2 α ; n = 143 and Control; n = 137), at random day of the estrous cycle. All heifers received 300 IU of equine chorionic gonadotropin (eCG) and 0.5 mg of estradiol cypionate (as ovulatory stimulus) when the NORG ear implants were removed. Timed artificial insemination (TAI) was performed 48 h after implant removal and the pregnancy diagnosis was conducted 30 days later. No effects on the P /AI due to PGF 2 α treatment were observed (PGF 2 α = 51.7 vs. Control = 57.7%; P = 0.29). In conclusion, PGF 2 α treatment at the onset of NORG-based protocols for the synchronization of ovulation did not alter the ovarian follicular responses or the P /AI in cyclic Bos indicus beef heifers synchronized for TAI.

The present study evaluated the use of sex-sorted sperm upon estrus detection (ED) or following timed artificial insemination (TAI) in lactating dairy cows. Additionally, the effect of the presence of a corpus luteum (CL) at the beginning of the TAI protocol was verified. Cows (539 crossbred Gir × Holstein and 87 Holstein) were classified according to the presence or absence of CL by ultrasonography exam. Cows with a CL were randomly assigned into one of two groups (CL-ED/AI or CL-TAI), and cows without a CL (NoCL-TAI) received TAI. Cows from the CL-ED/AI group received 500mg of cloprostenol intramuscularly and were inseminated 12h after ED in the following five days. Cows from the TAI groups (CL or NoCL) received TAI. Cows receiving CL-ED/AI had a lower (P

Exogenous eCG for stimulation of a single dominant follicle or for superovulation are common strategies to improve reproductive efficiency by increasing pregnancy rates and embryo production, respectively. Morphofunctional changes in the CL of eCG-treated cattle include increases in CL volume and plasma progesterone concentrations. Therefore, we tested the hypothesis that eCG alters the content of luteal cells and mitochondria related to hormone production. Twelve crossbred beef cows were synchronized and then allocated into three groups (four cows per group) and received no further treatment (control) or were given eCG either before or after follicular deviation (superovulation and stimulation of the dominant follicle, respectively). Six days after ovulation, cows were slaughtered and CL collected for morphohistologic and ultrastructural analysis. Mitochondrial volume per CL was highest in superovulated followed by stimulated and then control cows (18,500 ± 2630, 12,300 ± 2640, and 7670 ± 3400 μm3; P < 0.001), and the density of spherical mitochondria and the total number of large luteal cells were increased (P < 0.05) in stimulated cows compared with the other two groups (110.32 ± 14.22, 72.26 ± 8.77, and 70.46 ± 9.58 mitochondria per μm3 and 678 ± 147, 245 ± 199, and 346 ± 38 × 106 cells, respectively. However, the largest diameters of the large luteal cells were increased in superovulated and control cows versus stimulated ones (32.32 ± 0.06, 31.59 ± 0.81, and 29.44 ± 0.77 μm; P < 0.0001). In contrast, the total number of small luteal cells was increased in superovulated cows (1456 ± 268, 492 ± 181, and 822 ± 461 × 106, P < 0.05). In conclusion, there were indications of cellular changes related to increased hormonal production (stimulatory treatment) and increased CL volume (superovulatory treatment).

Oocyte quality is known to be a major cause of infertility in repeat-breeder (RB) and heat-stressed dairy cows. However, the mechanisms by which RB oocytes become less capable of supporting embryo development remain largely unknown. Thus, the aim of this study was to investigate whether the decreased oocyte competence of RB cows (RBs) during summer is associated with an altered gene expression profile and a decrease in mitochondrial DNA (mtDNA) copy number. Therefore, oocytes collected from heifers, non-RBs in peak lactation (PLs), and RBs were used to evaluate mtDNA amounts as well as the expression levels of genes associated with the mitochondria (MT-CO1, NRF1, POLG, POLG2, PPARGC1A, and TFAM), apoptosis (BAX, BCL2, and ITM2B), and oocyte maturation (BMP15, FGF8, FGF10, FGF16, FGF17, and GDF9). The oocytes retrieved from RBs during winter contained over eight times more mtDNA than those retrieved from RBs during summer. They also contained significantly less mtDNA than oocytes retrieved from heifers and PLs during summer. Moreover, the expression of mitochondria- (NRF1, POLG, POLG2, PPARGC1A, and TFAM) and apoptosis-related (BAX and ITM2B) genes, as well as of GDF9, in RB oocytes collected during summer was significantly greater than that in oocytes collected from heifers and PLs during the same season. In oocytes from heifers and PLs, the expression levels of these genes were lower in those collected during summer compared with winter, but this difference was not observed in oocytes collected from RBs. Altogether, these data provide evidence of altered gene expression and reduced mtDNA copy number in the oocytes collected from RBs during summer. This indicates a loss of fertility in RBs during summer, which might be caused by a possible mitochondrial dysfunction associated with a greater chance of oocytes to undergo apoptosis.

We hypothesized that stimulatory and superovulatory treatments, using equine chorionic gonadotropin (eCG), modulate the expression of genes related to insulin, cellular modelling and angiogenesis signaling pathways in the bovine corpus luteum (CL). Therefore, we investigated: 1-the effect of these treatments on circulating insulin and somatomedin C concentrations and on gene and protein expression of INSR, IGF1 and IGFR1, as well as other insulin signaling molecules; 2-the effects of eCG on gene and protein expression of INSR, IGF1, GLUT4 and NFKB1A in bovine luteal cells; and 3-the effect of stimulatory and superovulatory treatments on gene and protein expression of ANG, ANGPT1, NOS2, ADM, PRSS2, MMP9 and PLAU. Serum insulin did not differ among groups (P = 0.96). However, serum somatomedin C levels were higher in both stimulated and superovulated groups compared to the control (P = 0.01). In stimulated cows, lower expression of INSR mRNA and higher expression of NFKB1A mRNA and IGF1 protein were observed. In superovulated cows, lower INSR mRNA expression, but higher INSR protein expression and higher IGF1, IGFR1 and NFKB1A gene and protein expression were observed. Expression of angiogenesis and cellular modelling pathway-related factors were as follows: ANGPT1 and PLAU protein expression were higher and MMP9 gene and protein expression were lower in stimulated animals. In superovulated cows, ANGPT1 mRNA expression was higher and ANG mRNA expression was lower. PRSS2 gene and protein expression were lower in both stimulated and superovulated animals related to the control. In vitro, eCG stimulated luteal cells P4 production as well as INSR and GLUT4 protein expression. In summary, our results suggest that superovulatory treatment induced ovarian proliferative changes accompanied by increased expression of genes providing the CL more energy substrate, whereas stimulatory treatment increased lipogenic activity, angiogenesis and plasticity of the extracellular matrix (ECM).

The impressive increase in the use of assisted reproductive technologies (ARTs), especially in cattle, during the last few years in Brazil is well known worldwide. In 2015, there were over 13.7 million artificial inseminations (AI), of which, about 77% were carried out using fixed-time AI (FTAI). This technology has helped to substantially improve reproductive efficiency in beef and dairy cattle. In relation to embryo transfer, production of in vivo derived (IVD) embryos remained relatively stable, with average production of 30-40,000 embryos per year, whereas in vitro production (IVP) of embryos had a substantial increase, from about 12,500 IVP embryos in 2000 to more than 300,000 IVP embryos after 2010. The increasing availability and use of sex-sorted sperm was one of the factors responsible for a recent shift from the predominance of IVP embryos from beef breeds to dairy breeds in Brazil. Moreover, there was also an increase from 13% in 2014 to 29% in 2015 in the percentage of vitrified/frozen embryos. Moreover, the successful use of protocols for fixed-time ET (FTET) due to their high efficiency and ease of implementation, has facilitated the dissemination of ET programs all over Brazil. However, there is room for improvement, since there are several reports of high pregnancy loss and high peripartum loss, when IVP embryos are used. The production of healthy cattle by somatic cell nuclear transfer has also increased in the last few years in Brazil, but despite substantial progress in reducing postnatal losses, no drastic increase in cloning efficiency up to parturition has occurred.

The effects of eCG on follicular growth, ovulation, and pregnancy per artificial insemination (P/AI) in multiparous and primiparous Bos indicus beef cows submitted to timed artificial insemination (TAI) were evaluated in three experiments. In experiments 1 (follicular responses; n = 64), 2 (follicular growth and ovulation rate; n = 662), and 3 (P/AI; n = 2092), cows submitted to TAI were assigned to receive one of two treatments on Day 8 of the synchronization protocol: control (no additional treatment) or eCG (300-IU of eCG intramuscularly). In experiment 1, largest follicle (LF) diameter on Day 8 (P = 0.56) and the interval from progesterone (P4)-device removal to ovulation (P = 0.79) did not differ between treatments. However, the maximum diameter of the LF (P = 0.05) and ovulation rate (P = 0.03) were greater in cows that received eCG. In experiment 2, the diameter of the LF on Day 10, follicular growth, and ovulation rate were greater in eCG-treated cows (P < 0.01). However, CL diameter was similar between treatments (P = 0.11). In experiment 3, there was a treatment-by-parity interaction (P = 0.003) on P/AI, such that treatment with eCG was more effective in primiparous cows. In conclusion, eCG treatment resulted in increased final follicular growth, ovulation rate, and fertility in B indicus cows submitted to TAI protocols, especially in primiparous cows.

The success of IVP is ultimately dependent on the number and quality of the cumulus-oocyte complexes (COC) harvested during the OPU procedure. Several factors appear to be critical to oocyte quality including follicle size, environment factors such as heatstress, genetic background, age and lactation status of donor animals, all having a remarkable influence on the results of IVP. The aim of this review is to highlight some critical areas that can help veterinary practitioners to enhance OPU efficiency and successfully implement IVP into their routine practice. Focus will be given to recent findings in the literature and underlying physiological aspects that may be interfering with the quality of oocytes addressed to IVP in cattle at younger ages (calves and prepubertal heifers), pregnant vs nonpregnant status, and possible interactions with lactation and days postpartum during OPU.

Made available in DSpace on 2013-09-27T14:54:13Z (GMT). No. of bitstreams: 1 WOS000306538100005.pdf: 677147 bytes, checksum: 85b60cc0df260829547c4b04d26d5950 (MD5) Previous issue date: 2012-08-01 Made available in DSpace on 2013-09-30T18:25:16Z (GMT). No. of bitstreams: 1 WOS000306538100005.pdf: 677147 bytes, checksum: 85b60cc0df260829547c4b04d26d5950 (MD5) Previous issue date: 2012-08-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:42:37Z No. of bitstreams: 1 WOS000306538100005.pdf: 677147 bytes, checksum: 85b60cc0df260829547c4b04d26d5950 (MD5) Made available in DSpace on 2014-05-20T13:42:37Z (GMT). No. of bitstreams: 1 WOS000306538100005.pdf: 677147 bytes, checksum: 85b60cc0df260829547c4b04d26d5950 (MD5) Previous issue date: 2012-08-01 Ourofino Agronegocio (Cravinhos, SP, Brazil) RG Genetica Avancada (Agua Boa, MS, Brazil) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The effects of estradiol benzoate (EB) and estradiol cypionate (EC) on induction of ovulation after a synchronized LH surge and on fertility of Bos indicus females submitted to timed AI (TAI) were evaluated. In Experiment 1, ovariectomized Nelore heifers were used to evaluate the effect of EB (n = 5) and EC (n = 5) on the circulating LH profile. The LH surge timing (19.6 and 50.5 h; P = 0.001), magnitude (20.5 and 9.4 ng/mL; P = 0.005), duration (8.6 and 16.5 h; P = 0.001), and area under the LH curve (158.6 and 339.4 ng/mL; P = 0.01) differed between the EB and EC treatments, respectively. In Experiment 2 (follicular responses; n = 60) and 3 (pregnancy per AI; P/AI; n = 953) suckled Bos indicus beef cows submitted to an estradiol/progesterone-based synchronization protocol were assigned to receive one of two treatments to induce synchronized ovulation: 1 mg of EB im 24 h after progesterone (P4) device removal or 1 mg of EC im at P4 device removal. There was no difference (P > 0.05) between EB and EC treatments on follicular responses (maximum diameter of the ovulatory follicle, 13.1 vs. 13.9 mm; interval from progesterone device removal to ovulation, 70.2 vs. 68.5 h; and ovulation rate, 77.8 vs. 82.8%, respectively). In addition, P/AI was similar (P < 0.22) between the cows treated with EB (57.5%; 277/482) and EC (61.8%; 291/471). In conclusion, despite pharmacologic differences, both esters of estradiol administered either at P4 device removal (EC) or 24 h later (EB) were effective in inducing an LH surge which resulted in synchronized ovulations and similar P/AI in suckled Bos indicus beef cows submitted to TAI. (C) 2012 Elsevier B.V. All rights reserved. Univ São Paulo, FMVZ, Dept Anim Reprod, BR-09500900 São Paulo, Brazil APTA Vale Paraiba Reg Ctr, Pindamonhangaba, SP, Brazil Ouro Fino Saúde Anim, Ribeirao Preto, SP, Brazil UNESP, Dept Support Anim Prod & Hlth, Aracatuba, SP, Brazil Universidade Federal de Lavras (UFLA), Dept Anim Sci, Lavras, MG, Brazil UFPB, Ctr Vet Sci, Areia, PB, Brazil UNESP, Dept Support Anim Prod & Hlth, Aracatuba, SP, Brazil

Contents Over the last several decades, a number of therapies have been developed that manipulate ovarian follicle growth to improve oocyte quality and conception rates in cattle. Various strategies have been proposed to improve the responses to reproductive biotechnologies following timed artificial insemination (TAI), superovulation (SOV) or ovum pickup (OPU) programmes. During TAI protocols, final follicular growth and size of the ovulatory follicle are key factors that may significantly influence oocyte quality, ovulation, the uterine environment and consequently pregnancy outcomes. Progesterone concentrations during SOV protocols influence follicular growth, oocyte quality and embryo quality; therefore, several adjustments to SOV protocols have been proposed depending on the animal category and breed. In addition, the success of in vitro embryo production is directly related to the number and quality of cumulus oocyte complexes harvested by OPU. Control of follicle development has a significant impact on the OPU outcome. This article discusses a number of key points related to the manipulation of ovarian follicular growth to maximize oocyte quality and improve conception rates following TAI and embryo transfer of in vivo- and in vitro-derived embryos in cattle.

Three experiments were designed to evaluate methods to optimize the use of sex-sorted sperm in timed AI (TAI) programs for suckled beef cows. In all 3 experiments, suckled Bos indicus cows were synchronized using an intravaginal progesterone (P4) device during 8 d and a 2.0-mg injection of intramuscular estradiol benzoate (EB) at device insertion. The females received PG and eCG (300 IU) at P4 device removal and 1.0 mg of EB 24 h later. The cows were inseminated 60 to 64 h after P4 device withdrawal. All cows had their ovaries scanned by transrectal ultrasound at TAI to indentify and to measure the largest follicle (LF) present. In Exp. 1, a total of 853 cows had their LF classified as

The challenge of getting dairy cows pregnant during early lactation is a well-described, worldwide problem. However, specifically in farms with poor reproductive, nutritional, and environmental conditions/management, a low pregnancy rate during early lactation is followed inevitably by an increased number of nonpregnant cows after 150 days in milk, with even more difficulties to achieve pregnancy. Therefore, several studies were designed to understand and develop strategies to mitigate reduced fertility of cows during late lactation. Experiments were performed under tropical regions to determine metabolic status during lactation and association of stage of lactation on oocyte quality and fertility. Lactating cows with extended days not pregnant (e.g.,>150 days in milk) often had systemic metabolic alterations, including development of peripheral insulin resistance and various oocyte alterations, including reduced expression of genes encoding glucose transport proteins, reduced amounts of mtDNA, increased expression of mitochondria-related genes, and increased expression of apoptosis-related genes. Additionally, in vitro embryo production and pregnancy per AI were lower in late- versus early-lactation cows in some but not all studies. Notwithstanding, when a normal embryo was transferred to a cow in late lactation, the pregnancy per transfer was reasonable, reinforcing the assertion that fertility problems in late-lactation cows may be associated with oocyte quality, fertilization, and/or failure of early embryo development. In conclusion, insulin resistance may reduce oocyte competence and consequently fertility in late-lactation dairy cows.

Fixed-time artificial insemination (FTAI) has been regarded as the most useful method to increase the number of cows inseminated in a given herd. The main treatments for FTAI in beef cattle are based on the use of progesterone-releasing devices and GnRH or estradiol to synchronize follicle wave emergence, with a mean pregnancy per AI (P/AI) around 50%. However, more recent protocols based on GnRH (named 5-day Co-Synch) or estradiol (named J-Synch) that reduce the period of progesterone device insertion and extend the period from device removal to FTAI have been reported to improve P/AI in beef cattle. Furthermore, treatments to resynchronize ovulation for a second FTAI in nonpregnant cows have provided the opportunity to do sequential inseminations and achieve high P/AI in a breeding season, reducing or even eliminating the need for clean-up bulls. In summary, FTAI protocols have facilitated the widespread application of AI in beef cattle, primarily by eliminating the necessity of estrus detection in beef herds.

The present study aimed to evaluate the efficacy of different inducers of new follicular wave emergence (FWE) and ovulation in fixed-time artificial insemination (FTAI) synchronization protocols using norgestomet ear implants (NORG) in Bos indicus cattle. In Experiment 1, the synchronization of FWE was evaluated when two different estradiol esters in different doses [2mg estradiol benzoate (EB), 2.5mg EV or 5mg estradiol valerate (EV)] were administered with NORG implant insertion in B. indicus cattle (estrous cyclic heifers and cows with suckling calves; n=10 per treatment). After estradiol treatment, ovarian ultrasonic exams were performed once daily to detect the interval between treatment and FWE. There were significant treatment-by-animal category interaction (P=0.05) on the interval from the estradiol treatment to FWE. An earlier (P0.0001) and less variable (P=0.02) interval from estradiol treatment to FWE was observed in heifers treated with EB (2.5±0.2; mean±SE) than in those treated with 2.5mg EV (4.2±0.3) or 5mg EV (6.1±0.6). Cows treated with 5mg EV (4.0±0.5) had longer (P=0.05) interval than cows receiving EB (2.5±0.2), however, there was an intermediate interval in those cows treated with 2.5mg EV (3.1±0.4). In Experiment 2, the number of uses of the NORG implant (new; n=305 or previously used once; n=314) and three different ovulation induction hormones [0.5mg estradiol cypionate (EC) at implant removal (n=205), 1mg EB given 24h after implant removal (n=219), or 100μg gonadorelin (GnRH) given at FTAI (n=195)] were evaluated in Nelore heifers (2×3 factorial design). Similar pregnancy per AI (P/AI; 30 days after FTAI; P0.05) were achieved using each of the three ovulation induction hormones (EB=40.6%; EC=48.3%, or GnRH=48.7%) and with a new (47.2%) or once-used NORG implant (44.3%). In Experiment 3, the effect of different ovulation induction hormones for FTAI [1mg EC at NORG implant removal (n=228), 10μg buserelin acetate at FTAI (GnRH; n=212) or both treatments (EC+GnRH; n=215)] on P/AI was evaluated in suckled beef cows treated with a once-used NORG implant and EB to synchronize the FWE. Similar P/AI (P=0.71) were obtained using GnRH (50.9%), EC (51.8%) or both treatments (54.9%) as ovulation induction hormones. Therefore, both doses of EV (2.5 or 5.0mg) with NORG implant delayed and increased the variation of the day of new FWE compared with EB in B. indicus cattle. These effects were more pronounced in B. indicus heifers than cows. Synchronization protocols for FTAI with either a new or once-used NORG implant with EB at insertion to induce a new FWE and either the use of EB, EC or GnRH as ovulation induction hormones may be successful in B. indicus heifers. Also, when a once-used NORG implant was used, either the administration of EC, GnRH or both as ovulation inducers resulted in similar P/AI in suckled B. indicus cows, showing no additive effect of the combination of both ovulation induction hormones.

Two experiments were designed to evaluate the effect of different insemination times (12 and 24h or 18 and 30h) and different types of semen (sex-sorted or non-sorted sperm) on embryo production in Nelore (Bos indicus) and Holstein (Bos taurus) superstimulated donors. In the first experiment, hormonal superstimulation of ovarian follicular development in Nelore donors (n=71) was performed in randomly allocated animals to one of the three treatment groups, and they were inseminated at 12 and 24h after an ovulatory stimulus with pLH treatment was applied, either with sex-sorted (4.2×10(6) sperm/insemination; S12/24; n=17) or non-sorted sperm (20×10(6) sperm/insemination; NS12/24; n=18), or they were inseminated at 18 and 30h using sex-sorted sperm (4.2×10(6) sperm/insemination; S18/30; n=19). A greater number of transferable embryos were found when sex-sorted sperm was used to inseminate the animals at 18 and 30h (4.5±3.0) compared to insemination at 12 and 24h (2.4±1.8; P

The objective of this study was to evaluate the productive performance, nutrients digestion and metabolism of three different genetic groups fed with the same diet based on corn silage. 30 heifers in growth were used of three groups of cattle, the following: Nellore ( Bos taurus indicus ) (n = 10), Holstein ( Bos taurus taurus ) (n = 10), and Mediterranean buffaloes ( Bubalis bubalis ) (n = 10). The animals were fed in groups and received the same experimental diet composed of corn silage and concentrate for growing heifers. In the evaluation of animals the performance, consumption and total apparent digestibility of dry matter and nutrients with the aid of internal markers (chromic oxide) and external (iADF), rumen fermentation, excretion of purine derivatives, nitrogen balance and blood metabolites were measured. No differences were observed in animal performance. There were differences in nutrient intake and apparent digestibility of dry matter and nutrients in different groups of cattle. The concentration of ammonia nitrogen (NH3-N) and short chain fatty acids (SCFA) in the rumen were higher and lower, respectively, for the group of buffaloes in relation to other experimental groups evaluated. When considering the excretion of total purine derivatives, buffaloes showed the lowest value compared to other genetic groups evaluated; about 61.76% of the total genetic group Nellore and 57.62% of the total genetic group Holstein with an average of 33.67 mmol/day. For the buffaloes, the excretion of xanthine and hypoxanthine observed was of 5.11% of total purine derivatives. There was a better nitrogen balance (g/day) for groups of Holstein heifers and Nellore in relation to the group of buffalo heifers. There were differences in the concentrations of urea and urea nitrogen in serum and liver enzymes where the buffaloes had higher values in relation at the bovines. There is a great metabolic diversity among the experimental groups evaluated and it was more exacerbated among buffaloes and bovines, when submitted to the same diet and same management conditions.

It was hypothesized the lower fertility of repeat-breeder (RB) Holstein cows is associated with oocyte quality and this negative effect is enhanced during summer heat stress (HS). During the summer and the winter, heifers (H; n = 36 and 34, respectively), peak-lactation (PL; n = 37 and 32, respectively), and RB (n = 36 and 31, respectively) Holstein cows were subjected to ovum retrieval to assess oocyte recovery, in vitro embryonic developmental rates, and blastocyst quality [terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells and total cell number]. The environmental temperature and humidity, respiration rate, and cutaneous and rectal temperatures were recorded in both seasons. The summer HS increased the respiration rate and the rectal temperature of PL and RB cows, and increased the cutaneous temperature and lowered the in vitro embryo production of Holstein cows and heifers. Although cleavage rate was similar among groups [H = 51.7% ± 4.5 (n = 375), PL = 37.9% ± 5.1 (n = 390), RB = 41.9% ± 4.5 (n = 666)], blastocyst rate was compromised by HS, especially in RB cows [H = 30.3% ± 4.8 (n = 244) vs. 23.3% ± 6.4 (n = 150), PL = 22.0% ± 4.7 (n = 191) vs. 14.6% ± 7.6 (n = 103), RB = 22.5% ± 5.4 (n = 413) vs. 7.9% ± 4.3 (n = 177)]. Moreover, the fragmentation rate of RB blastocysts was enhanced during the summer, compared with winter [4.9% ± 0.7 (n = 14) vs. 2.2% ± 0.2 (n = 78)] and other groups [H = 2.5% ± 0.7 (n = 13), and PL = 2.7% ± 0.6 (n = 14)] suggesting that the association of RB fertility problems and summer HS may potentially impair oocyte quality. Our findings provide evidence of a greater sensitivity of RB oocytes to summer HS.

Made available in DSpace on 2013-09-27T14:54:12Z (GMT). No. of bitstreams: 1 WOS000288627700007.pdf: 187475 bytes, checksum: f44a03d706cf45e64484e91ab7b27272 (MD5) Previous issue date: 2011-02-01 Made available in DSpace on 2013-09-30T18:36:09Z (GMT). No. of bitstreams: 1 WOS000288627700007.pdf: 187475 bytes, checksum: f44a03d706cf45e64484e91ab7b27272 (MD5) Previous issue date: 2011-02-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:42:31Z No. of bitstreams: 1 WOS000288627700007.pdf: 187475 bytes, checksum: f44a03d706cf45e64484e91ab7b27272 (MD5) Made available in DSpace on 2014-05-20T13:42:31Z (GMT). No. of bitstreams: 1 WOS000288627700007.pdf: 187475 bytes, checksum: f44a03d706cf45e64484e91ab7b27272 (MD5) Previous issue date: 2011-02-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The objectives of this study were to determine the interval from ovulation to deviation and the diameter of the dominant (DF) and largest subordinate (SF) follicles at deviation in buffalo (Bubalus bubalis) heifers. Two methods of evaluation (observed vs. calculated) were used. FSH and LH profiles encompassing follicle deviation (Experiment 1), and the follicular diameter when the DF acquired ovulatory capacity (Experiment 2) were also determined. The time of deviation and the diameter of the of and the largest SF at deviation did not differ between observed and calculated methods. Overall, follicle deviation occurred 2.6 +/- 0.2 d (mean SEM) after ovulation, and the diameters of the DF and SF at deviation were 7.2 +/- 0.2 and 6.4 +/- 0.2 mm, respectively. No changes in plasma levels of FSH or LH were observed (P= 0.32 and P= 0.96, respectively). Experiment 2 was conducted in two phases according to the diameter of the of during the first wave of follicular development at the time of LH challenge (25 mg of pLH). In the first phase, follicles ranging from 5.0 to 6.0 mm (n = 7), 6.1 to 7.0 mm (n = 11), or 7.1 to 8.0 mm (n= 9) were used, and in the second phase, follicles ranging from 7.0 to 8.4 mm (n=10), 8.5 to 10.0 mm (n = 10), or 10.1 to 12.0 mm (n = 9) of diameter were used. After the pLH treatment, the of was monitored by ultrasonography every 12 h for 48 h. No ovulations occurred in heifers in the first phase. However, in the second phase, an effect of follicular diameter was observed on ovulation rate [7.0-8.4 mm (0.0%, 0/10), 8.5-10.0 mm (50.0%, 5/10), and 10.0-12.0 mm (55.6%, 5/9)]. In summary, follicle deviation occurred 2.6d after ovulation in buffalo (B. bubalis) heifers, when the diameters of the DF and SF were 7.2 and 6.4 mm, respectively. No significant changes in plasma concentrations of FSH or LH were detected. Finally, the acquisition of ovulatory capacity occurred when the of reached 8.5 mm in diameter. (C) 2010 Elsevier B.V. All rights reserved. FMVZ USP, Dept Anim Reprod, BR-05508270 São Paulo, Brazil APTA Registro, Registro, SP, Brazil Autonomous Veterinarian, Vicosa, MG, Brazil UFMA, Ctr Ciencias Agr & Ambientais, Chapadinha, MA, Brazil IB UNESP, Dept Bioestatist, Botucatu, SP, Brazil IB UNESP, Dept Farmacol, Botucatu, SP, Brazil Lab Endocrinol UNESP, Dept Apoio & Prod Saúde Anim, Aracatuba, SP, Brazil Univ Saskatchewan, Western Coll Vet Med, Saskatoon, SK S7N 0W0, Canada IB UNESP, Dept Bioestatist, Botucatu, SP, Brazil IB UNESP, Dept Farmacol, Botucatu, SP, Brazil Lab Endocrinol UNESP, Dept Apoio & Prod Saúde Anim, Aracatuba, SP, Brazil FAPESP: 03/10203-4

Ovulation induction (OI) is a cornerstone of human assisted reproduction treatments (ART). Current OI protocols are based on the human follicular dynamics model known as propitious moment theory (PMT), by which follicles continuously grow from the primordial pool without any pattern, and follicular fate depend on the occurrence of a gonadotropin surge. Recently, a new paradigm of human follicular dynamics called follicular waves was revealed using sequential ultrasound examination of 1 interovulatory interval. Instead of random growth, follicles develop in coordinated groups or waves, occurring 2 to 3 times during an interovulatory interval. Follicular waves are common in several other mono-ovulatory species, like equines and bovines. In fact, this model was applied to the development of several OI protocols in veterinary medicine, especially in cows. It has been shown that synchronization of OI with the emergence of a follicular wave increases substantially success rates in animals, even with single embryo transfer. Veterinarians have already developed mechanisms to control wave emergence through mechanical or chemical ablation of the dominant follicle or corpus luteum. Considering the follicular dynamics similarities between humans and bovines regarding the follicular wave phenomenon, we hypothesize that synchronization of follicular wave emergence with ovarian stimulation produces more competent oocytes and embryos and will enhance ART efficiency in humans. At the end of this article, we propose 2 theoretical approaches to induce the emergence of a follicular wave in women: (1) a mechanical strategy by aspiration of the dominant follicle and (2) a pharmacological strategy by administering estradiol and progesterone.

This review brings together information on ovarian physiology in buffaloes including folliculogenesis, ovulation, and the development and function of the corpus luteum. Features of embryonic development are also considered. The buffalo is classified as a short-day breeder but in equatorial zones can show oestrous cycles throughout the year provided that nutrition is adequate to maintain reproductive function. In sub-tropical zones and at higher latitudes, day length is often the major determinant of reproductive function including the occurrence of regular oestrous cycles, duration of oestrus, and the period to resumption of ovulation postpartum. Indeed, at higher latitudes buffaloes that give birth during the period of increasing day length may not show a resumption of ovulation until the following period of decreasing day length. This can have a major impact on the productive value of buffaloes and requires the development and utilisation of practical and effective assisted breeding technology for out-of-season breeding in buffaloes. Embryonic development in buffaloes occurs at a faster rate than in cattle and this has implications for the earlier establishment and functionality of the corpus luteum in buffaloes. It would appear that the interrelationships between the development of the early conceptus, corpus luteum function, uterine preparation, and maternal recognition of pregnancy, are more closely time-bound in buffaloes compared with cattle. The phase of embryonic attachment would seem to be a critical period for determining the reproductive outcome in buffaloes.

The objectives of the present study were to evaluate factors associated with estrous synchronization responses and pregnancy per insemination (P/AI) in Bos indicus beef cows submitted to progesterone-based fixed-time artificial insemination (FTAI) protocols. A total of 2388 cows (1869 Nellore and 519 crossbred NellorexAngus) from 10 commercial farms were evaluated to determine the relationships among breed, body condition score (BCS) on the first day of the FTAI protocol, the occurrence of estrus between progesterone device removal and FTAI, and diameter of largest ovarian follicle (LF) at FTAI on estrous synchronization responses and P/AI. Cows (n=412 primiparous; 1976 multiparous) received an intravaginal device containing progesterone or an ear implant containing norgestomet (a progestin), and an injection of estradiol at the beginning of the estrous synchronization protocol. Body condition was scored using a 1-5 scale on the first day of the FTAI protocol and at 30-60 days postpartum. Females received 300IU of equine chorionic gonadotropin (eCG) and PGF(2alpha) on the day the progesterone device/implant was removed and were inseminated 48-60h later. At insemination, cows (n=2388) were submitted to an ultrasonographic exam to determine the diameter of the LF. Follicles were classified into four categories based on mean and standard deviation (SD) of the LF (LF1=two SD below the mean; LF2=mean minus one SD; LF3=mean plus one SD; LF4=two SD above the mean). Ovulation rate was determined in a subset of cows (n=813) by three consecutive ultrasonographic exams: (1) at time of progesterone device/implant removal, (2) at time of FTAI and (3) 48h after FTAI. Ovulation was defined as the disappearance of a large follicle (>or=8.0mm) that was previously recorded. Estrus was determined in a subset of the cows (n=445) by the activation of a detection of estrous patch placed on the tail head on the day of progesterone device/implant removal. Pregnancy was diagnosed 30 days after FTAI. Pregnancy was influenced (P=0.001) by follicle diameter [LF1=27.5% (81/295), LF2=46.6% (328/705), LF3=57.9% (647/1118), LF4=63.3% (171/270)] and the occurrence of estrus [estrus=67.7% (174/257) and no estrus=36.2% (68/188)]. Follicle diameter at FTAI influenced ovulation rate [LF1=42.5% (34/80), LF2=73.9% (161/218), LF3=95.8% (407/425), LF4=97.8% (88/90)], the occurrence of estrus [LF1=54.8% (51/93), LF2=33.6% (43/128), LF3=68.9% (126/183), LF4=90.2% (37/41)] and P/AI among cows that had ovulations [LF1=32.4% (11/34), LF2=50.3% (81/161), LF3=60.0% (244/407), LF4=68.2% (60/88)]. Improving estrous responses between progesterone device withdrawal and FTAI and increasing the diameter of the LF at FTAI may be important aspects to achieve improved estrous synchronization responses and P/AI following progesterone/progestin and estradiol based FTAI protocols in suckled Bos indicus cows.

A total of 177 Nelore heifers were examined by ultrasonography to determine the presence or absence of a corpus luteum (CL) and received a 3 mg norgestomet ear implant plus 2 mg of estradiol benzoate i.m. On Day 8, implants were removed and 150 μg of d -cloprostenol i.m. was administered. At the time of norgestomet implant removal, heifers with or without CL at the time of initiating treatment were assigned equally and by replicate to be treated with 0 IU ( n = 87) or 400 IU ( n = 90) eCG i.m. All heifers received 1 mg of EB i.m. on Day 9 and were submitted to fixed-time artificial insemination (FTAI) 30–34 h later. The addition of eCG increased the diameter of the largest follicle (LF) at FTAI (10.6 ± 0.2 mm vs. 9.5 ± 0.2 mm; P = 0.003; mean ± SEM), the final growth rate of the LF (1.14 ± 0.1 mm/day vs. 0.64 ± 0.1 mm/day; P = 0.0009), ovulation rate [94.4% (85/90) vs. 73.6% (64/87); P = 0.0006], the diameter of the CL at Day 15 (15.5 ± 0.3 mm vs. 13.8 ± 0.3 mm; P = 0.0002), serum concentrations of progesterone 5 days after FTAI (6.6 ± 1.0 ng/ml vs. 3.6 ± 0.7 ng/ml; P = 0.0009), and pregnancy per AI [P/AI; 50.0% (45/90) vs. 36.8% (32/87); P = 0.04]. The absence of a CL at the beginning of the treatment negatively influenced the P/AI [30.2% (16/53) vs. 49.2% (61/124); P = 0.01]. Therefore, the presence of a CL (and/or onset of puberty) must be considered in setting up FTAI programs in heifers. In addition, eCG may be an important tool for the enhancement of follicular growth, ovulation, size and function of the subsequent CL, and pregnancy rates in progestin-based FTAI protocols in Bos indicus heifers.

The aim of the present study was to compare a synchronization of time of ovulation protocol for fixed-timed embryo transfer (FTET) with the usual administration of a single dose of prostaglandin associated with detection of estrus. Also, the effect of the presence of CL at the beginning of FTET protocol was evaluated. Lactating Holstein cows (n=651) with three previous artificial inseminations were classified according to presence or absence of a corpus luteum (CL). Cows with a CL were randomly assigned to two additional treatments and submitted to embryo transfer after detection of estrus (PGF-Estrus) or FTET (FTET-CL). Cows without CL were allocated to the FTET-NoCL treatment. On a random day of the estrous cycle (Day 0), cows in the PGF-Estrus treatment (n=229) were treated with 150 microg d-cloprostenol (PGF) i.m. followed by detection of estrus from Day 1 through Day 5 after PGF. Embryos were transferred 6-8 days after estrus detection. Cows in the FTET-CL (n=208; presence of CL) and FTET-NoCL (n=214; absence of CL) treatments received a norgestomet ear implant plus 2mg estradiol benzoate (EB) and 50mg progesterone i.m. on Day 0. On Day 8, the implant was removed and 400 IUeCG, 150 microg d-cloprostenol and 1mg estradiol cypionate i.m. were administered. No detection of estrus was performed and Day 10 was arbitrarily considered as the estrus day. Ultrasonographic exams were performed in all recipients and only cows with a single CL> or =15 mm or multiple CL received a fresh or frozen-thawed embryo on Day 17. Pregnancy was diagnosed by ultrasonography at 30 and 60 days of pregnancy. When FTET and PGF-Estrus were compared, the proportion of cows receiving an embryo (recipients transferred-to-treated rate) was greater in the FTET-CL (75.0% (156/208) than in PGF-Estrus (34.5%, 79/229; P

Two experiments were conducted to investigate the effects of equine chorionic gonadotropin (eCG) at progestin removal and gonadotropin-releasing hormone (GnRH) at timed artificial insemination (TAI) on ovarian follicular dynamics (Experiment 1) and pregnancy rates (Experiment 2) in suckled Nelore (Bos indicus) cows. Both experiments were 2 × 2 factorials (eCG or No eCG, and GnRH or No GnRH), with identical treatments. In Experiment 1, 50 anestrous cows, 134.5 ± 2.3 d postpartum, received a 3 mg norgestomet ear implant sc, plus 3 mg norgestomet and 5 mg estradiol valerate im on Day 0. The implant was removed on Day 9, with TAI 54 h later. Cows received 400 IU eCG or no further treatment on Day 9 and GnRH (100 μg gonadorelin) or no further treatment at TAI. Treatment with eCG increased the growth rate of the largest follicle from Days 9 to 11 (means ± SEM, 1.53 ± 0.1 vs. 0.48 ± 0.1 mm/d; P < 0.0001), its diameter on Day 11 (11.4 ± 0.6 vs. 9.3 ± 0.7 mm; P = 0.03), as well as ovulation rate (80.8% vs. 50.0%, P = 0.02), whereas GnRH improved the synchrony of ovulation (72.0 ± 1.1 vs. 71.1 ± 2.0 h). In Experiment 2 (n = 599 cows, 40 to 120 d postpartum), pregnancy rates differed (P = 0.004) among groups (27.6%, 40.1%, 47.7%, and 55.7% for Control, GnRH, eCG, and eCG + GnRH groups). Both eCG and GnRH improved pregnancy rates (51.7% vs. 33.8%, P = 0.002; and 48.0% vs 37.6%, P = 0.02, respectively), although their effects were not additive (no significant interaction). In conclusion, eCG at norgestomet implant removal increased the growth rate of the largest follicle (LF) from implant removal to TAI, the diameter of the LF at TAI, and rates of ovulation and pregnancy rates. Furthermore, GnRH at TAI improved the synchrony of ovulations and pregnancy rates in postpartum Nelore cows treated with a norgestomet-based TAI protocol.

Artificial insemination (AI) in buffalo has limited use worldwide due the difficulties in the estrus detection and in finding an adequate moment for this procedure. Therefore, an alternative to increase the number of buffalo that are inseminated is the use of protocols that allow the AI without the need of estrus detection, usually called fixed-time AI (FTAI). Our expanding knowledge of the control of follicular wave dynamics during the buffalo estrous cycle has resulted in renewed enthusiasm for the prospects of precisely control of the follicular and luteal dynamics and finely controlling the time of ovulation. Follicular wave development can be controlled by treatments with GnRH or estradiol and progestogen/progesterone in combination. Treatment of buffalo with GnRH in combination with prostaglandin F2α (PGF2α) 7 d later and a second GnRH 48 h after PGF2α (known as Ovsynch) has resulted in acceptable pregnancy rates after FTAI in cycling buffalo during the breeding season. FTAI protocols using progestin devices, estradiol and eCG have resulted in synchronous onset of a new follicular wave, synchronous ovulation and consistent pregnancy rates in anestrous buffalo during the off breeding season. The combination of these protocols permits the use of AI throughout the year, obtaining conception and calving even in anestrus buffalo during the off breeding season.

The aim of the present study was to determine the relationship among body weight (BW), body condition score (BCS) and rump fat thickness (RFAT) measured by ultrasonography, and validate the relationship between BCS and RFAT over the time. Two hundred sixty and six Nelore cows had their BW, BCS and RFAT evaluated at five different moments during the production cycle: M1) weaning; M2) parturition, M3) 42 days post-partum; M4) 82 days post-partum and M5) 112 days post-partum. A BCS value was attributed for each cow following a 1 to 5 points scale. Ultrasonographic images for RFAT measurement were obtained using a 3.5 MHz linear transducer. Images were immediately analyzed as soon as they were formed and frozen. Body condition scores and ultrasound measurements were collected on the same day by a single trained technician. The relationship between BCS and RFAT values was investigated by regression models. The analysis of similarity among the five obtained models was performed using the proc MIXED from SAS and the correlations among variables were analyzed with proc CORR from SAS. The BCS was able to predict RFAT in Nelore cows in all different moments evaluated. Also, it was shown that BCS presented high correlation (r = 0.82 to 0.93) and relationship (R2 = 0.73 to 0.92) with RFAT. However, both BCS and RFAT showed low correlation (r = 0.37 to 0.50) and relationship (R2 = 0.13 to 0.25) with BW. The BCS classification by visual method using a 1 to 5 point scale, was able to predict the RFAT in Nelore cows over the time.

This review aims to clarify some aspects of early buffalo reproduction and ovarian activity with special regard to corpus luteum (CL) activity. Puberty has been regarded as a complex event that is signalled by the first cyclic progesterone secretion at >1 ng/ml, in tight relation to other hormones such as luteinizing hormone (LH) and growth hormone (GH). CL activity has been described in relation to the peculiarities of the oestrus cycle of the species, such as seasonal reproductive aptitude and the bull effect. The importance of the CL in pregnancy establishment and maintenance has also been revised in the light of the results of the latest research about embryo mortality in buffalo.

The present study investigated how the timing of the administration of estradiol benzoate (EB) impacted the synchronization of ovulation in fixed-time artificial insemination protocols of cattle. To accomplish this, two experiments were conducted, with EB injection occurring at different times: at withdrawal of the progesterone-releasing (P4) intravaginal device or 24h later. The effectiveness of these times was compared by examining ovarian follicular dynamics (Experiment 1, n=30) and conception rates (Experiment 2, n=504). In Experiment 1, follicular dynamics was performed in 30 Nelore cows (Bos indicus) allocated into two groups. On a random day of the estrous cycle (Day 0), both groups received 2mg of EB i.m. and a P4-releasing intravaginal device, which was removed on Day 8, when 400 IU of eCG and 150 microg of PGF were administered. The control group (G-EB9; n=15) received 1mg of EB on Day 9, while Group EB8 (G-EB8; n=15) received the same dose a day earlier. Ovarian ultrasonographic evaluations were performed every 8h after device removal until ovulation. The timing of EB administration (Day 8 compared with Day 9) did affect the interval between P4 device removal to ovulation (59.4+/-2.0 h compared with 69.3+/-1.7h) and maximum diameter of dominant (1.54+/-0.06 acm compared with 1.71+/-0.05 bcm, P=0.03) and ovulatory (1.46+/-0.05 acm compared with 1.58+/-0.04 bcm, P0.01) follicles. In Experiment 2, 504 suckling cows received the same treatment described in Experiment 1, but insemination was performed as follows: Group EB8-AI48 h (G-EB8-AI48 h; n=119) and Group EB8-AI54 h (G-EB8-AI54 h; n=134) received 1mg of EB on Day 8 and FTAI was performed, respectively, 48 or 54 h after P4 device removal. Group EB9-AI48h (G-EB9-AI48 h; n=126) and Group EB9-AI54 h (G-EB9-AI54 h; n=125) received the same treatments and underwent the same FTAI protocols as G-EB8-AI48 h and G-EB8-AI54 h, respectively; however, EB was administered on Day 9. Conception rates were greater (P0.05) in G-EB9-AI54 h [63.2% (79/125) a], G-EB9-AI48 h [58.7% (74/126) a] and G-EB8-AI48 h [58.8% (70/119) a] than in G-EB8-AI54 h [34.3% (46/134) b]. We concluded that when EB administration occurred at device withdrawal (D8), the interval to ovulation shortened and dominant and ovulatory follicle diameters decreased. Furthermore, when EB treatment was performed 24h after device removal, FTAI conducted at either 48 or 54 h resulted in similar conception rates. However, EB treatment on the same day as device withdrawal resulted in a lesser conception rate when FTAI was conducted 54 h after device removal.

The objective was to determine whether exposure of Gir (Bos indicus) cows to heat-stress (HS) causes immediate and delayed deleterious effect on follicular dynamics, hormonal profile and oocyte competence. The cows were kept in tie-stalls for an adaptive thermoneutral period of 28 days (Phase I, Days -28 to -1). In Phase II (Days 0-28) cows were randomly allocated into control (CG, n=5) and HS (HS, n=5) treatments. The HS cows were placed in an environmental chamber at 38 degrees C and 80% relative humidity (RH) during the day and 30 degrees C, 80% RH during the night for 28 days. The CG group was maintained in shaded tie-stalls (ambient temperature) for 28 days. During Phase III (Days 28-147) animals were placed in tie-stalls (Days 28-42) followed by pasture (Days 42-147) under thermoneutrality. In each phase, weekly ovum pick up (OPU) sessions were to evaluate follicular development, morphology of cumulus-oocyte complexes (COCs), and developmental competence after in vitro maturation, fertilization, and culture. Serum concentrations of progesterone (P(4)) and cortisol were evaluated by radioimmunoassay. Exposure of Gir cows to HS had no immediate effect on reproductive function, but exerted a delayed deleterious effect on ovarian follicular growth, hormone concentrations, and oocyte competence. Heat-stress increased the diameter of the first and second largest follicles from Days 28 to 49. Indeed, HS increased the number of >9 mm follicles (characterized as follicular codominance) during this phase. Cows exposed to HS had longer periods of non-cyclic activity (P(4)

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:07:07Z No. of bitstreams: 1 S1516-35982007000600010.pdf: 128963 bytes, checksum: 5fbf4319f217e24368f6112c951c279b (MD5) Made available in DSpace on 2013-08-22T19:07:07Z (GMT). No. of bitstreams: 1 S1516-35982007000600010.pdf: 128963 bytes, checksum: 5fbf4319f217e24368f6112c951c279b (MD5) Previous issue date: 2007-10-01 Made available in DSpace on 2013-09-30T20:11:33Z (GMT). No. of bitstreams: 2 S1516-35982007000600010.pdf: 128963 bytes, checksum: 5fbf4319f217e24368f6112c951c279b (MD5) S1516-35982007000600010.pdf.txt: 34485 bytes, checksum: 66d6c0f72949901eee5a980d7c23dc4e (MD5) Previous issue date: 2007-10-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:49:05Z No. of bitstreams: 2 S1516-35982007000600010.pdf: 128963 bytes, checksum: 5fbf4319f217e24368f6112c951c279b (MD5) S1516-35982007000600010.pdf.txt: 34485 bytes, checksum: 66d6c0f72949901eee5a980d7c23dc4e (MD5) Made available in DSpace on 2014-05-20T13:49:05Z (GMT). No. of bitstreams: 2 S1516-35982007000600010.pdf: 128963 bytes, checksum: 5fbf4319f217e24368f6112c951c279b (MD5) S1516-35982007000600010.pdf.txt: 34485 bytes, checksum: 66d6c0f72949901eee5a980d7c23dc4e (MD5) Previous issue date: 2007-10-01 Avaliaram-se os efeitos da remoção temporária de bezerros (RTB) ou da aplicação de gonadotrofina coriônica eqüina (eCG) na taxa de prenhez (TP) de vacas Nelore lactantes tratadas com um dispositivo intravaginal liberador de progesterona (DILP). No experimento 1, 83 vacas Nelore e 102 mestiças (Nelore × Red Angus) foram distribuídas em três grupos. em dia aleatório do ciclo estral (D0), os animais do grupo 1 foram tratados com benzoato de estradiol (BE; 2,5 mg, IM, Estrogin®) e um DILP (1 g de progesterona, DIB®), removido no D9, quando também se administrou d-cloprostenol (150 µg, IM, Prolise®) e aproximadamente 12 horas após identificação do estro realizou-se a inseminação artificial. No grupo 2 (IATF), o tratamento foi semelhante ao aplicado no grupo 1, porém, administrou-se uma segunda dose de benzoato de estradiol (1 mg) no D10 e 30-36 horas mais tarde realizou-se a inseminação artificial em tempo fixo (IATF). No grupo 3 (IATF/RTB), os bezerros foram removidos a partir do D9 até a inseminação artificial com tempo fixo (IATF). As taxas de prenhez para as vacas Nelore e mestiças foram, respectivamente, de 7,69 e 41% (Controle); 23,52 e 59,57% (IATF); 69,44 e 55,81% (IATF/RTB). No experimento 2, 255 vacas Nelore lactantes foram distribuídas em três grupos. Os animais do grupo 4 (IATF) foram tratados com benzoato de estradiol (2 mg) e um DILP (1,9 g de progesterona, CIDR-B®) no D0 e no D8 sofreram remoção do DILP no D8 e administração de 25 mg de dinoprost (IM, Lutalyse®). No D9, foi aplicado benzoato de estradiol (1 mg) realizando-se a IATF 30-36 horas mais tarde. No grupo 5 (IATF/RTB), os bezerros foram removidos no D9 até a IATF. O grupo 6 (eCG) foi semelhante ao IATF, exceto pela aplicação de eCG no D9 (400 UI, IM, Novormon®). As taxas de prenhez foram de 50,57 (IATF), 53,57 (IATF/RTB) e 54,76% (eCG). A associação de RTB ao tratamento hormonal com DILP aumenta as taxas de prenhez, enquanto a adição de eCG ao tratamento não melhora as taxa de prenhez de vacas Nelore lactantes ciclando e em boa condição corporal. This study aimed to evaluate the effects of temporary calf removal (TCR) or eCG administration on pregnancy rates of milking Nelore cows treated with a intravaginal progesterone releasing device (IPRD). In the first experiment 83 Nelore and 102 Nelore vs. Red Angus crossbred cows were randomly allocated to 3 groups. Animals in Group 1 (CON) received estradiol benzoate (EB; 2.5 mg, i.m., Estrogin®) and an IPRD (1g progesterone, DIB®) in a random stage of the estrous cycle (D0). At D9 the IPRD was removed and the animals were treated with d-cloprostenol (150µg, i.m., Prolise®). The animals were artificially inseminated (AI) 12 h after estrus detection. Group 2 (FTAI) was similar to CON, except that another dose of EB (1mg) was administered at D10, and 30-36 hours later artificial insemination (FTAI) was performed at a fixed time. In Group 3 (FTAI/TCR) the calves were removed from D9 to the FTAI. Pregnancy rates for Nelore and crossbred cows were, respectively, 7.69 and 41% (CON); 23.52 and 59.57 (FTAI); 69.44 and 55.81 (FTAI/TCR). In the second experiment, 255 lactating Nelore cows were allocated to 3 groups. At D0, animals in Group 4 (FTAI) received EB (2 mg) and one IPRD (1.9g progesterone, CIDR-B®), which was removed at D8 when the cows received 25 mg of dinoprost (i.m., Lutalyse®). At D9 EB (1 mg) was administered and 30-36 hours later all animas were FTAI. In Group 5 (FTAI/TCR) the calves were removed from D9 to FTAI. The Group 6 (eCG) was similar to IATF except for the administration of eCC in D9 (400 IU, i.m., Novormon®). Pregnancy rates were: 50.57% (FTAI), 53.57% (FTAI/TCR) and 54.76% (eCG). These results indicated that TCR associated with IPRD increase pregnancy rates, whereas the addition of eCG to IPRD do not improve pregnancy rates in Nelore cows which are cycling and in lactation with good body condition. UNESP Instituto de Biociências Departamento de Farmacologia Faculdades Integradas de Campo Mourão Departamento de Reprodução Animal UEL Centro de Ciências Agrárias Departamento de Clínicas Veterinárias USP FMVZ Departamento de Reprodução Animal UNESP Instituto de Biociências Departamento de Farmacologia

The adaptation of Bos indicus cattle to tropical and subtropical environments has led to their widespread distribution around the world. Although artificial insemination (AI) is one of the best alternatives to introduce new genetics into Bos indicus herds, the peculiarity of their temperament and the tendency to show short oestrus (many of them during the night) greatly affects the effectiveness of genetic improvement programs. Therefore, the most useful alternative to increase the number of females that are inseminated is the use of protocols that allow for AI without the need for oestrus detection, usually called fixed-time AI (FTAI). Besides, the development of protocols to advance the resumption of cyclicity during the early postpartum period has a great impact on beef production and will allow for the inclusion of a significantly larger population of animals into genetic improvement programs. Fixed-time AI protocols using progestin devices, oestradiol and eCG have resulted in consistent pregnancy rates in suckled Bos indicus and Bos indicus x Bos taurus cows. Furthermore, fertility in the successive cycles and the overall pregnancy rates at the end of the breeding season, have been shown to be improved by the use of progestin devices at the beginning of the breeding season. In summary, exogenous control of luteal and follicular development has facilitated the application of assisted reproductive technologies in Bos indicus-influenced cattle, by offering the possibility of planning programs without the necessity of oestrus detection and may provide the opportunity to improve reproductive performance of beef cattle in tropical climates.

Oocyte quality is known to be a major cause of infertility in repeat-breeder (RB) and heat-stressed dairy cows. However, the mechanisms by which RB oocytes become less capable of supporting embryo development remain largely unknown. Thus, the aim of this study was to investigate whether the decreased oocyte competence of RB cows (RBs) during summer is associated with an altered gene expression profile and a decrease in mitochondrial DNA (mtDNA) copy number. Therefore, oocytes collected from heifers, non-RBs in peak lactation (PLs), and RBs were used to evaluate mtDNA amounts as well as the expression levels of genes associated with the mitochondria (MT-CO1, NRF1, POLG, POLG2, PPARGC1A, and TFAM), apoptosis (BAX, BCL2, and ITM2B), and oocyte maturation (BMP15, FGF8, FGF10, FGF16, FGF17, and GDF9). The oocytes retrieved from RBs during winter contained over eight times more mtDNA than those retrieved from RBs during summer. They also contained significantly less mtDNA than oocytes retrieved from heifers and PLs during summer. Moreover, the expression of mitochondria- (NRF1, POLG, POLG2, PPARGC1A, and TFAM) and apoptosis-related (BAX and ITM2B) genes, as well as of GDF9, in RB oocytes collected during summer was significantly greater than that in oocytes collected from heifers and PLs during the same season. In oocytes from heifers and PLs, the expression levels of these genes were lower in those collected during summer compared with winter, but this difference was not observed in oocytes collected from RBs. Altogether, these data provide evidence of altered gene expression and reduced mtDNA copy number in the oocytes collected from RBs during summer. This indicates a loss of fertility in RBs during summer, which might be caused by a possible mitochondrial dysfunction associated with a greater chance of oocytes to undergo apoptosis.

Made available in DSpace on 2018-12-11T16:40:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-03-15 Plasma FSH profiles, in vitro embryo production (IVP) after ovum pickup (OPU), and establishment of pregnancy with IVP embryos were compared in untreated Holstein oocyte donors and those superstimulated with multiple injections or a single intramuscular (IM) injection of porcine FSH (pFSH) in hyaluronan (HA). Plasma FSH profiles were determined in 23 heifers randomly allocated to one of four groups. Controls received no treatment, whereas the F200 group received 200 mg of pFSH in four doses, 12 hours apart. The F200HA and F300HA groups received 200- or 300-mg pFSH in 5 mL or 7.5 mL, respectively of a 0.5% HA solution by a single IM injection. Plasma FSH levels were determined before the first pFSH treatment and every 6 hours over 96 hours. All data were analyzed by orthogonal contrasts. Circulating FSH area under curve (AUC) in pFSH-treated animals was greater than that in the control group (P = 0.02). Although the AUC did not differ among FSH-treated groups (P = 0.56), the total period with elevated plasma FSH was greater in the F200 group than in the HA groups (P < 0.0001). However, the F300HA group had a greater AUC than the F200HA group (P = 0.006), with a similar total period with elevated plasma FSH (P = 0.17). The IVP was performed in 90 nonlactating Holstein cows randomly allocated to one of the four treatment groups as in the first experiment. A greater proportion of medium-sized (6-10 mm) follicles was observed in cows receiving pFSH, regardless of the treatment group (P < 0.0001). Also, numbers of follicles (P = 0.01), cumulus-oocyte complexes (COCs) retrieved (P = 0.01) and matured (P = 0.02), cleavage rates (P = 0.002), and blastocysts produced per OPU session (P = 0.06) were greater in cows receiving pFSH, regardless of the treatment group. Cows in the F200HA group had a greater recovery rate (P = 0.009), number of COCs cultured (P = 0.04), and blastocysts produced per OPU session (P = 0.06) than cows in the F300HA group. Similar pregnancy rates were observed 50 to 60 days after transferring IVP embryos from donors in the different treatment groups (P > 0.05). In conclusion, a single IM injection of pFSH combined in 0.5% HA resulted in similar plasma FSH profiles as twice-daily pFSH treatments. Treatment of nonlactating donors with pFSH, with or without HA, resulted in increased IVP over untreated controls. A single dose of 200 mg of pFSH in 0.5% HA resulted in greater IVP than 300-mg pFSH in HA. Finally, pregnancy rates with IVP embryos were similar, regardless donor treatment. Departamento de Reprodução Animal FMVZ/USP Clínica Veterinária Samvet São Carlos FinInVitro Reprodução Animal Departamento de Reprodução Animal UNESP NeoGen Reprodução Assistida Instituto de Reproducción Animal Córdoba (IRAC) Department of Large Animal Clinical Sciences Western College of Veterinary Medicine University of Saskatchewan Departamento de Reprodução Animal UNESP

Four experiments were designed to evaluate the effect of different circulating progesterone (P4) concentrations during a synchronization of ovulation protocol for the timed artificial insemination (TAI) of Bos indicus (Nelore) beef cattle. In the first trial, 13 ovariectomized Nelore heifers were randomly allocated into one of three groups using new P4 devices (New; 1.0 g P4), previously used P4 devices for 8 days (Used1x), and previously used P4 devices for 16 days (Used2x), in a crossover experimental design. The circulating P4 concentrations during the P4 device treatment were lower for Used1x (2.3 ± 0.1 ng/mL) and Used2x (2.0 ± 0.1 ng/mL) than those for New (3.8 ± 0.2 ng/mL; P = 0.001). In the second trial, the ovarian follicular dynamics of 60 anestrous cows were evaluated after the cows received the treatments described previously (New [n = 20], Used1x [n = 20], and Used2x [n = 20]). During the insertion of the P4 device, the cows were administered 2.0-mg estradiol benzoate. Eight days later, the P4 device was removed, and the cows were administered 0.53-mg sodium cloprostenol, 300 IU eCG, and 1-mg estradiol cypionate. There were no differences among the groups during the interval from P4 device removal to ovulation (73.7 ± 2.9 vs. 69.8 ± 2.4 vs. 68.4 ± 2.3 hours) or regarding the ovulation rate (70.0% vs. 80.0% vs. 85.0%). However, the maximum diameter of the largest follicle was greater (P = 0.06) in the Used2x (15.3 ± 0.4 mm) than that of New (13.5 ± 0.8 mm) and Used1x (14.9 ± 0.5 mm). In experiment 3, 443 anestrous cows were randomly assigned into one of the three treatments (New [n = 144] vs. Used1x [n = 167] vs. Used2x [n = 132]) and received a TAI 48 hours after the P4 device removal. The diameter of the largest follicle during the device removal (10.7 ± 0.3 vs. 11.2 ± 0.2 vs. 11.3 ± 0.3 mm) and the 30-day pregnancy rates (51.4% vs. 53.9% vs. 43.2%) did not differ among the experimental groups. In experiment 4, a field trial with 593 B indicus (Nelore) cows was conducted to evaluate the pregnancy per AI using different levels of P4 in a TAI protocol (New [n = 189] vs. Used1x [n = 203] vs. Used2x [n = 201]). The pregnancy per AI was similar between the treatment groups (63.5% vs. 57.6% vs. 62.7%). In conclusion, the low circulating P4 concentrations that were released from a used P4 device efficiently controlled the ovarian follicular growth and exhibited no detrimental effects on the pregnancy rates of the B indicus (Nelore) beef cattle.

This study was conducted to evaluate the influence of category (heifers, primiparous or multiparous cows) on pregnancy rates in a large scale resynchronization ovulation program. Nelore heifers (n = 903), primiparous lactating cows (n = 338) and multiparous lactating cows (n = 1,223) were synchronized using a conventional protocol of estradiol/P4-based fixed-time artificial insemination (FTAI). Thirty days after ultrasonography, females who failed the first FTAI were resynchronized with the same hormonal protocol prior to a second FTAI. The pregnancy status of each cohort was evaluated by ultrasonography 30 days after each FTAI. The average conception rate after the first FTAI and resynchronization was 80.5%. Heifers had a higher conception rate (85%) than primiparous (76%) or multiparous cows (78%; p = 0.0001). The conception rate after the first FTAI was similar among heifers (57%), primiparous cows (51%) and multiparous cows (56%; p = 0.193). After the second FTAI, heifers exhibited a higher conception rate (66%) than primiparous or multiparous cows (51%; p = 0.0001). These results demonstrate the feasibility of resynchronization in large beef herds for providing consistent pregnancy rates in a short period of time. We also demonstrated that ovulation resynchronization 30 days after FTAI is particularly effective for heifers, providing a conception rate of up to 66%.

Compared to Bos taurus breeds, Bos indicus breeds of cattle present several differences in reproductive physiology. Follicular diameter at deviation and at the time of ovulatory capability are smaller in B. indicus breeds. Furthermore, B. indicus breeds have a greater sensitivity to gonadotropins, a shorter duration of estrus, and more often express estrus during the night. These differences must be considered when setting up embryo transfer programs for B. indicus cattle. In recent studies, we evaluated follicular dynamics and superovulatory responses in B. indicus donors with the objective of implementing fixed-time AI protocols in superstimulated donors. Protocols using estradiol and progesterone/progestrogen releasing devices to control follicular wave emergence were as efficacious as in B. taurus cattle, allowing the initiation of superstimulatory treatments (with lower dosages of FSH than in B. taurus donors) at a self-appointed time. Furthermore, results presented herein indicate that delaying the removal of progesterone/progestogen-releasing devices, combined with the administration of GnRH or pLH 12 h after the last FSH injection, results in synchronous ovulations, permitting the application of fixed-time AI of donors without the necessity of estrus detection and without compromising the results.

This study evaluated the effect of new or used P4 devices on the ovarian responses of dairy buffalo that were administered an estradiol (E2) plus progesterone (P4)-based timed artificial insemination (TAI) protocol during the breeding season. On the first day of the TAI protocol, 142 cows were randomly assigned to receive one of the following: a new device (New; 1.0 g of P4; n = 48); a device that had previously been used for 9 days (Used1x, n = 47); or a device that had previously been used for 18 days (Used2x, n = 47). Ultrasound was used to evaluate the following: the presence of a corpus luteum (CL); the diameter of the dominant follicle (ØDF) during protocol; ovulatory response; and pregnancies per AI (P/AI). Despite similar responses among the treatments, there was a significant positive association of the ØDF during TAI protocol with ovulatory responses and number of pregnancies. In conclusion, satisfactory ovarian responses and a satisfactory pregnancy rate were achieved when grazing dairy buffalo were subjected to the TAI protocol in breeding season, independent of whether a new or used P4 device was used. Furthermore, the presence of the larger follicle was associated with a higher ovulation rate and higher P/AI following TAI.

Most of the world's bovine herd is found in tropical regions. Bos indicus predominates, due to their adaptation to the climate and management conditions. Anestrous is the main factor that negatively affects reproductive performance of animals bred in these regions of the globe. Several factors affect postpartum anestrous, including suckling and maternal-offspring bond, and pre- and postpartum nutritional status. The short duration of estrus and the tendency to show estrus during the night, greatly affect the efficiency of artificial insemination (AI) programs in B. indicus cattle managed in tropical areas. Several restricted suckling or weaning procedures (temporary or permanent), and hormonal treatments have been used to induce ovulation and cyclicity in postpartum cows. Most hormonal treatments are based on progesterone/progestogen (P4) releasing devices associated with estradiol benzoate (EB), or a combination of GnRH/PGF(2alpha)/GnRH (Ovsynch). Treatments with GnRH/PGF(2alpha)/GnRH has presented inconsistent results, probably due to the variable number of cows in anestrous. Treatments using P4 devices and EB have resulted in apparently more consistent results than Ovsynch programs in B. indicus cattle; however, pregnancy rates are low in herds presenting high anestrous rates and moderate to low body condition. The addition of an eCG treatment at the time of device removal, which increased plasma progesterone concentrations and pregnancy rates in anestrous postpartum suckled B. indicus cows, may be useful to improve reproductive performance of beef cattle in tropical climates.

The potential to use a GnRH agonist bioimplant and injection of exogenous LH to control the time of ovulation in a multiple ovulation and embryo transfer (MOET) protocol was examined in buffalo. Mixed-parity buffalo (Bubalus bubalis; 4-15-year-old; 529 13 kg LW) were randomly assigned to one of five groups (n = 6): Group 1, conventional MOET protocol; Group 2, conventional MOET with 12 It delay in injection of PGF(2alpha); Group 3, implanted with GnRH agonist to block the pre-ovulatory surge release of LH; Group 4, implanted with GnRH agonist and injected with exogenous LH (Lutropin(R), 25 mg) 24 h after 4 days of superstimulation with FSH; Group 5, implanted with GnRH agonist and injected with LH 36 h after superstimulation with FSH. Ovarian follicular growth in all buffaloes was stimulated by treatment with FSH (Folltropin-V(R), 200 mg) administered over 4 days, and was monitored by ovarian ultrasonography. At the time of estrus, the number of follicles greater than or equal to8 mm. was greater (P < 0.05) for buffaloes in Group 2 (12.8) than for buffaloes in Groups 1 (8.5), 3 (7.3), 4 (6.1) and 5 (6.8), which did not differ. All buffaloes were mated by AI after spontaneous (Groups 1-3) or induced (Groups 4 and 5) ovulation. The respective number of buffalo that ovulated, number of corpora lutea, ovulation rate (%), and embryos + oocytes recovered were: Group 1 (2, 1.8 +/- 1.6, 18.0 +/- 13.6, 0.2 +/- 0.2); Group 2 (4, 6.1 +/- 2.9, 40.5 +/- 17.5, 3.7 +/- 2.1); Group 3 (0, 0, 0, 0); Group 4 (6, 4.3 +/- 1.2, 69.3 +/- 14.2, 2.0 +/- 0.9); and Group 5 (1, 2.5 +/- 2.5, 15.5 +/- 15.5, 2.1 +/- 2.1). All buffaloes in Group 4 ovulated after injection of LH and had a relatively high ovulation rate (69%) and embryo recovery (46%). It has been shown that the GnRH agonist-LH protocol can be used to improve the efficiency of MOET in buffalo.

We evaluated the efficiency of replacing GnRH with LH in the ovulation synchronization protocol in buffaloes. Buffaloes received GnRH on Day 0, (Buserelin; Conceptal, 20 microg), PGF2alpha (Luprostiol; Prosolvin, 15 mg) on Day 7 and GnRH (Buserelin; Conceptal, 10 microg; Group 1) or porcine LH (LH; Lutropin-V, 12.5 mg; Group 2) on Day 9. In Experiment 1, we studied the follicular dynamics of 30 buffaloes (Group 1, n = 15 and Group 2, n = 15). We performed ultrasonography every 12 h from Days 0 to 2, then on Day 7 and then every 6 h from the time of GnRH or LH treatment (Day 9) until the time of ovulation. All females not ovulating by 48 h after the second GnRH or LH injection were considered as nonresponders. In Experiment 2, we evaluated 305 buffaloes (Group 1, n = 154; Group 2, n = 151), using the same two treatments studied in Experiment 1. We also recorded and evaluated aspects like parity, lactational status, the presence of mucus, and uterine tone at the time of artificial insemination (Al). In Experiment 1, ovulation rate after the first GnRH was 86.6% (26/30). Ovulation rates were 93.3% (14/15; Group 1) after the second dose of GnRH and 93.3% (14/15) after LH (Group 2). Ovulation occurred 36.4+/-10.4 h after the first GnRH. The interval for treatment to ovulation was 26.5+/-9.6 h for buffaloes treated with GnRH (Group 1) and 24.4+/-7.9 h for buffaloes treated with LH (Group 2); the time of ovulation did not differ statistically between the two groups (GnRH versus LH; P0.05). In Experiment 2, conception rates of the animals AI in the field were 56.5% (Group 1) and 64.2% (Group 2), respectively (P = 0.08). The response to the treatment with LH was not different to the treatment with GnRH; however, multiparous buffaloes had higher conception rates than the primiparous buffaloes in both groups (P0.05). Buffaloes with mucus at the time of AI in Group 2 had higher conception rates than the buffaloes that had mucus in Group 1 (P0.05). Uterine tone and lactational status did not influence conception rates (P0.05). In summary, the results showed that both treatments resulted in synchronization of ovulation and acceptable conception rates. Therefore, the exogenous injection of LH can substitute the GnRH injections in the Ovsynch program in buffaloes.

This study aimed to induce follicular wave emergence (FWE) using pharmacological (recombinant hCG administration) or mechanical (aspiration of dominant follicle) interventions in infertile women.Sixteen infertile women (≤35 years) with indications for in vitro fertilization due to tubal and/or male factor infertility were randomized into three groups: control (n = 6), pharmacological (n = 5) and mechanical (n = 5) groups. Women in both experimental groups underwent serial transvaginal sonograms (TVS) from menstrual cycle day 10 until identification of a dominant follicle ≥15 mm. Women in the pharmacological group received 250 μg of recombinant-hCG to induce ovulation, and resumed serial TVS 2 days later. In the mechanical group, dominant and subordinate follicles ≥10 mm were aspirated, and daily TVS was resumed on the following day. An increased pool of follicles ≥5 and ≤9 mm after interventions characterized FWE. Women in the control group underwent ovulation induction (OI) with 150 IU/day of recombinant follicle-stimulating hormone started on menstrual cycle day 3 (D3). OI was started on the day of FWE in the experimental groups. Endometrial asynchrony with development of the embryo was expected in the experimental groups. Therefore, all viable embryos were cryopreserved and transferred in an endometrial-stimulated cycle.The number of follicles ≥5 and ≤9 mm increased after the interventions in both experimental groups (p .001), indicating induction of FWE. OI outcomes were similar among the groups.The pharmacological and mechanical interventions are efficient in inducing FWE; outcomes of OI synchronized with FWE should be further investigated.

The aim of the present study was to evaluate the effect of bovine somatotropin (bST; 500mg) administration on lactating buffalo donors submitted to two different ovum pick-up (OPU) and in vitro embryo production schemes with a 7 or 14d intersession OPU interval. A total of 16 lactating buffalo cows were randomly assigned into one of four experimental groups according to the bST treatment (bST or No-bST) and the OPU intersession interval (7 or 14d) in a 2×2 factorial design (16 weeks of OPU sessions). The females submitted to OPU every 14d had a larger (P0.001) number of ovarian follicles suitable for puncture (15.6±0.7 vs. 12.8±0.4) and an increased (P=0.004) number of cumulus-oocyte complexes (COCs) recovered (10.0±0.5 vs. 8.5±0.3) compared to the 7d interval group. However, a 7 or 14d interval between OPU sessions had no effect (P=0.34) on the number of blastocysts produced per OPU (1.0±0.1 vs. 1.3±0.2, respectively). In addition, bST treatment increased (P0.001) the number of ovarian follicles suitable for puncture (15.3±0.5 vs. 12.1±0.4) but reduced the percentage (18.9% vs. 10.9%; P=0.009) and the number (1.4±0.2 vs. 0.8±0.1; P=0.003) of blastocysts produced per OPU session compared with the non-bST-treated buffaloes. In conclusion, the 14d interval between OPU sessions and bST treatment efficiently increased the number of ovarian follicles suitable for puncture. However, the OPU session interval had no effect on embryo production, and bST treatment reduced the in vitro blastocyst outcomes in lactating buffalo donors.

The aim of the present study was to evaluate the LH surge after EB (estradiol benzoate) or GnRH administration with or without P4 (progesterone) pre-exposure in ovariectomized (OVX) buffalo cows. Females were randomly assigned to receive an intravaginal P4 device (D0–D9). They were then given EB 24 h or GnRH 36 h post-P4 device removal (factorial 2×2, n=6 per group). Blood collection for LH measurement began 36 h after the P4 device removal and continued at 3 h intervals. The area under the LH curve (AUC; 30.2 ng2 and 13.41 ng2; P=0.007) and the area of the LH peak (AP; 19.0 ng2 and 8.9 ng2; P=0.009) were greater for EB than GnRH. We did not observe an effect of P4 pre-exposure on the AUC and AP. Furthermore, there was no interaction between P4 pre-exposure and EB or GnRH treatment on the AUC and AP. However, there was an interaction (P

The present study investigated the effect of Holstein donor category (cows vs. heifers) and climate variation (hot vs. cooler season) on the efficiency of in vivo embryo production programs as well as embryo survival after transferred to Holstein recipient cows. A total of 1562 multiple ovulation (MO) procedures (cows: n = 609, and heifers: n = 953) and 4076 embryo transfers (ETs) performed in two dairy herds were evaluated. Donor cows had greater number of CLs (10.6 ± 0.6 vs. 7.5 ± 0.4; P

Contents This study was performed to evaluate plasma concentrations of anti-Mullerian hormone (AMH) and the ovarian antral follicle population (AFP) in different genetic groups. Cyclic heifers (13 Bubalus bubalis [Murrah]; 15 Bos taurus [Holstein] and 10 Bos indicus [Gyr]) were maintained under the same management and were synchronized with two doses of 150 μg IM d-cloprostenol administered 14 days apart. After the second d-cloprostenol treatment, heifers had their ovaries scanned daily by ultrasound to define the day of ovulation. On the same day, the AFP was determined and a plasma sample was collected to measure AMH. Murrah heifers had less AFP (25.6 ± 2.1 follicles; p = 0.01) and plasma AMH concentration (0.18 ± 0.03 ng/ml; p

Three experiments were designed to evaluate the effect of different circulating progesterone (P4) concentrations during synchronization of ovulation protocol for timed artificial insemination of seasonal anestrous buffalo cows. In the first trial, ovariectomized cows were randomly allocated into one of three groups: using new P4 devices (G-New; n = 8), using devices previously used for 9 days (G-Used1x; n = 8), and using devices previously used for 18 days (G-Used2x; n = 8). The P4 device was maintained for 9 days, and the circulating P4 concentration was measured daily. The circulating P4 concentrations during the P4 device treatment were the lowest for G-Used2x (1.10 ± 0.04 ng/mL), intermediate for G-Used1x (1.52 ± 0.05 ng/mL), and the highest for G-New (2.47 ± 0.07 ng/mL; P = 0.001). In the second trial, 31 anestrous cows had their ovarian follicular dynamics evaluated after receiving the treatments described previously (G-New [n = 10], G-Used1x [n = 11], and G-Used2x [n = 10]). At insertion of the P4 device, cows were administered 2.0 mg of estradiol benzoate. Nine days later, the P4 device was removed and cows were administered 0.53 mg of cloprostenol sodium plus 400 IU of eCG. Forty-eight hours after P4 device removal, 10 μg of buserelin acetate was administered. There were no differences among the groups (G-New vs. G-Used1x vs. G-Used2x) in diameter of the largest follicle at P4 device removal (9.0 ± 0.8 vs. 10.1 ± 0.9 vs. 8.6 ± 0.8 mm; P = 0.35), in interval from P4 device removal to ovulation (77.1 ± 4.5 vs. 76.5 ± 4.7 vs. 74.0 ± 4.4 hours; P = 0.31), or in ovulation rate (80.0% vs. 81.8% vs. 60.0%; P = 0.51). In experiment 3, 350 anestrous cows were randomly assigned into one of the three treatments described previously (G-New, n = 111; G-Used1x, n = 121; G-Used2x, n = 118) and received a timed artificial insemination for 16 hours after buserelin treatment. The 30-day pregnancy rates did not differ among groups (55.9% vs. 55.4% vs. 48.3%; P = 0.39). Thus, the low circulating P4 concentrations released from a used P4 device efficiently control the ovarian follicular growth and had no detrimental effect on the pregnancy rates of the seasonal anestrous buffalo cows.