Thermoregulatory response of black or red lactating Holstein cows in the hot and cold season in southern Brazil.

Dairy cows in pasture-based systems are more susceptible to heat stress. Holstein cows have the black or red phenotypes, the latter having lower absorbance of solar radiation. Therefore, the study's objective was to evaluate whether cows with red (R) coats are more resistant than black (B) cows to hot weather in a subtropical climate. R and B lactating Holstein cows were evaluated during the cold and hot seasons for internal and surface temperature and sweating rate. In the cold season, body temperature (n = 9/group) did not differ between groups, but the average superficial temperature (n = 13/group) was lower in R cows (B: 30.9 ± 0.3 °C; RW: 29.6 ± 0.3 °C; p = 0.02). In the hot season, under mild to moderate heat stress, mean body temperature (n = 9/group) of R cows was lower (B: 38.75 ± 0.01 °C; R: 38.62 ± 0.1 °C; p=<0.0001), whereas no difference was observed in superficial temperature (n = 17/group). The maximum internal temperature and sweating rate (n = 11/group), measured in the hot season, and the number of evaluations in hyperthermia in both seasons did not differ. Therefore, there were differences in thermoregulation between phenotypes under mild to moderate heat stress conditions. However, considering that only discrete differences were observed, the red and white coat is unlikely to benefit the Holstein cow's welfare under mild to moderate thermal stress.

Does GnRH treatment at TAI regardless of estrus occurrence increase pregnancy rate in crossbred Bos taurus suckled cows?

The impact of GnRH treatment on the day of TAI in beef cows has received limited investigation, especially concerning its association with estrus expression. Consequently, two experiments were conducted to assess the potential of GnRH treatment on the day of TAI to enhance fertility according to the expression or not of estrus in beef cows. Experiment 1 aimed to determine ovulation rate and luteal function, while Experiment 2 aimed to determine the effect of the two GnRH treatment approaches on pregnancy rate. In Experiment 1, multiparous Brangus suckling cows (n = 17) were submitted to an 8-day TAI protocol. Estrus occurrence was evaluated based on chalk removal on D10 (TAI) and cows were assigned to receive GnRH (25µg lecirelin; im) according to the group: GnRH (n = 7), regardless of estrus expression; or selectGnRH (n = 10), only cows not detected in estrus. Ovulation rate occurring until 77h after IVD removal did not differ (p = 0.17) between GnRH (85.7%; 6/7) and selectGnRH (100%; 10/10). Also, corpus luteum size and serum progesterone concentration were not affected (p>0.05) by treatments. In Experiment 2, crossbred taurine suckled cows (n = 384) were submitted to the same protocol as described in Experiment 1 and were randomly allocated to GnRH or selectGnRH groups. There was no difference in P/AI between groups (selectGnRH = 55.6%; GnRH = 54.3%; p = 0.7) 30 days after TAI. As expected, there was a pronounced effect (p<0.0001) of estrus expression on P/AI (Estrus = 61.5%; No estrus = 33.0%), regardless of group. In summary, ovulation timing and rate and luteal function did not differ between groups. Also, GnRH administration only in cows that do not show estrus is recommended, considering hormone savings and similar conception rate.

Inter-software reliability and agreement for follicular and luteal morphometric and echotextural ultrasonographic parameters in beef cattle.

This study aimed to compare the inter-software and inter-observer reliability and agreement for the assessment of follicular and luteal morphometry and echotexture parameters in beef crossbreed females (3/8 Bos taurus indicus and 5/8 Bos taurus taurus). B-mode and color Doppler ultrasonographic ovarian images were obtained at specific time points of estradiol-progesterone-based protocols for timed artificial insemination (TAI). Sonograms were analyzed by two observers using a licensed (IASP1) and an open access (IASP2) software package. A total of 292 snap-shot sonograms were analyzed for morphometric parameters and 504 for echotexture parameters. inter-software reliability was judged moderate to excellent (ICC or CCC=0.73-0.98), whereas inter-observer reliability for morphometric parameters was deemed good to excellent (ICC or CCC=0.82-0.98). A small percentage (up to 10.95 %) of measured parameters fell outside the limits of inter-software and inter-observer agreement. For echotexture parameters, inter-software reliability varied widely (ICC or CCC=0.16-0.95) based on the size of regions of interest (ROI), while inter-observer reliability ranged from moderate to excellent (ICC or CCC= 0.71-0.97). The highest inter-software reliability for pixel value and heterogeneity value was observed for the corpus luteum (ICCs=0.81-0.95; P>0.05), followed by the peripheral follicular antrum (ICCs=0.75-0.78; P<0.05). However, lower reliability was determined for the follicular wall (ICCs=0.08-0.33; P<0.0001) and perifollicular stroma (ICCs=0.16-0.46; P<0.05). In conclusion, both software packages showed high reproducibility for morphometric measurements, while echotexture measurements were more challenging to replicate based on ROI sizes. Caution is advised when selecting ROI sizes for echotexture measurements in bovine ovaries.

Estratégias farmacológicas para a manipulação do ciclo estral de fêmeas bovinas de raças de corte taurinas / Pharmacological approaches to manipulate bovine estrous cycle in taurine beef breeds

Este texto discute as estratégias farmacológicas para a manipulação do ciclo estral de fêmeas taurinas de corte, com foco na inseminação artificial em tempo fixo (IATF). Os zebuínos, rebanho predominante no Brasil, apresentam características de ciclo estral diferentes das raças taurinas, o que justifica a busca por estratégias hormonais adaptadas para o controle do ciclo estral nas subespécies. O estradiol combinado com a progesterona (P4) e prostaglandina F2 alfa (PGF) é o esquema hormonal mais comumente utilizado para a manipulação do ciclo estral em protocolos de IATF. Porém, o uso de GnRH combinado ou em substituição aos ésteres de estradiol vem sendo considerado. Coletivamente, os dados do nosso grupo reforçam a necessidade de customizar as abordagens para o controle do ciclo estral de acordo com a composição genética das fêmeas bovinas.(AU)

This text discusses pharmacological strategies to manipulate the estrous cycle of taurine and synthetic females, with a focus on timed artificial insemination (TAI). Zebu cattle, the predominant herd in Brazil, have different estrous cycle characteristics than taurine breeds, requiring different synchronization hormonal strategies for each subspecies. Estradiol combined with progesterone (P4) and prostaglandin F2 alpha (PGF) is the most used hormonal scheme for estrous cycle manipulation in TAI protocols. But the use of GnRH instead of estradiol esters is being considered. Collectively, our group's data reinforce the need to customize approaches to estrous cycle control according to the genetic composition of bovine females.(AU)

Estudos para o incremento da produção de embriões in vivo e in vitro em vacas de corte taurinas e sintéticas / Studies to improve in vivo and in vitro embryo production in beef cows from taurine and synthetic breeds

O Brasil destaca-se por ser um dos líderes mundiais na produção in vitro de embriões, o que é decorrente do rebanho nacional ser predominantemente composto por raças zebuínas, que possuem maior número de folículos antrais aspiráveis. Por outro lado, vacas taurinas apresentam menor população folicular antral, o que limita o número de ovócitos obtidos por seção de aspiração folicular (ovum pick-up; OPU). Portanto, na região Sul do Brasil há demanda para produção tanto in vivo como in vitro de embriões de doadoras de raças taurinas e sintéticas. Este texto discute estudos recentes que buscam estratégias para aperfeiçoar as etapas envolvidas na produção de embriões bovinos, bem como para aumentar o aproveitamento de receptoras utilizadas nos programas de transferência de embriões (TE), com foco em vacas taurinas e sintéticas.(AU)

Brazil stands among the leaders on in vitro embryo production, as the Brazilian herd is predominantly composed by Zebu breeds, which have a greater number of antral follicles available to ovum pick-up (OPU). On the other hand, taurine cows have a lower antral follicle population, which limits the number of oocytes obtained by each OPU section. Therefore, in the Brazilian Southern region there is a demand for both in vivo and in vitro production of embryos from donors of taurine and synthetic breeds. This text discusses recent studies that seek strategies to improve the steps involved in the production of bovine embryos, as well as to increase the use of recipients in embryo transfer (ET) programs, focusing on taurine and synthetic cows.(AU)

Desafios e perspectivas na produção comercial de embriões in vivo e in vitro de raças taurinas e sintéticas / Current challenges and perspectives of in vivo and in vitro commercial embryo production of taurine and synthetic breeds

As biotécnicas de produção in vivo e in vitro de embriões bovinos permitem aumentar significativamente o número de descendentes de fêmeas genética e/ou zootecnicamente importantes. Porém, antes de se optar por um dos métodos, deve-se avaliar suas peculiaridades. A produção in vivo pode ser empregada de forma satisfatória tanto em zebuínos quanto em raças sintéticas e taurinas, permitindo a obtenção de, em média, seis a sete embriões viáveis por coleta, com boa tolerância à criopreservação. Já a produção in vitro é mais eficiente em raças zebuínas e sintéticas, visto que possuem maior número de folículos antrais aspiráveis. Além disso, esta técnica permite a produção de embriões sem estímulos hormonais exógenos, porém com menor criotolerância. Desse modo, a presente revisão discute os desafios atuais e perspectivas futuras na produção de embriões in vivo e in vitro com base nos dados da rotina de uma central de doadoras e laboratório de produção de embriões que desenvolve simultaneamente ambas as técnicas de produção de embriões na região Sul do Brasil.(AU)

Biotechniques for in vivo and in vitro production of bovine embryos allow to significantly increase the number of descendants from cows genetically and/or zootechnically superior. However, before opting for one of the methods, one should evaluate its peculiarities. In vivo production can be used satisfactorily both in zebu cattle and in synthetic and taurine breeds, allowing to obtain, on average, six to seven viable embryos per procedure, with good tolerance to cryopreservation. In vitro production is more efficient in Zebu and synthetic breeds, since they have a greater number of aspirable antral follicles. In addition, this technique allows the production of embryos without exogenous hormonal stimuli, but with lower cryotolerance. This review discusses current challenges and future perspectives in in vivo and in vitro embryo production based on routine data from an embryo production center and a laboratory that develop, simultaneously, the two embryo production techniques in southern Brazil.(AU)

Analysis of nuclear maturation, DNA damage and repair gene expression of bovine oocyte and cumulus cells submitted to ionizing radiation'

Radiotherapy causes destruction of tumor cells, but also threatens the integrity and survival of surrounding normal cells. Then, woman submitted to irradiation for cancer treatment may present permanent ovary damage, resulting in impaired fertility. The objective of this study was to investigate the effects of therapeutic doses of ionizing radiation (IR), used for ovarian cancer treatment in humans, on bovine cumulus-oocyte complexes (COCs) as experimental model. Bovine ovaries were exposed to 0.9 Gy, 1.8 Gy, 3.6 Gy or 18.6 Gy IR, and then COCs were collected and used to evaluate: (a) oocyte nuclear maturation; (b) presence of phosphorylated H2A.X (γH2AX), as an indicator of DNA double-strand breaks (DSBs); and (c) expression of genes involved in DNA repair (TP53BP1, RAD52, ATM, XRCC6 and XRCC5) and apoptosis (BAX). The radiation doses tested in this study had no detrimental effects on nuclear maturation and did not increase γH2AX in the oocytes. However, IR treatment altered the mRNA abundance of RAD52 (RAD52 homolog, DNA repair protein) and BAX (BCL2-associated X protein). We conclude that although IR doses had no apparent effect on oocyte nuclear maturation and DNA damage, molecular pathways involved in DNA repair and apoptosis were affected by IR exposure in cumulus cells.(AU)

Association between chronic Anaplasma marginale and Babesia spp. infection and hematological parameters of taurine heifers / Associação entre infecção crônica por Anaplasma marginale e Babesia spp. e parâmetros hematológicos de novilhas taurinas

The aim of this study was to investigate the association between chronic Anaplasma marginale and Babesia spp. infection and hematological parameters of pregnant and non-pregnant taurine heifers. Blood samples from 94 females were collected on the first day (D-10) of timed artificial insemination (TAI) protocol and on pregnancy diagnosis (D+34). Hematological parameters were determined and compared between pregnant (PG) and non-pregnant (NPG) heifers, and within group at different sampling days. Real-time PCR (qPCR) was used to determine A. marginale and Babesia bovis infection, and for absolute quantification of Babesia spp. between PG and NPG groups. Correlation analysis was performed between the number of gDNA copies (CN) of Babesia spp. and hematological parameters. On D-10, mean hemoglobin concentration was higher for NPG, and hematocrit and total plasma protein were higher on D+34 for both groups. There was no difference in Babesia spp. CN between groups. In the first qPCR, all heifers were positive for A. marginale and B. bovis. Significant correlations were found between hemoglobin and erythrocyte and between hemoglobin and hematocrit (r = 0.8082 and r = 0.3009, respectively). Low levels of A. marginale and Babesia spp. did not affect hematological parameters of chronically infected pregnant and non-pregnant taurine heifers.(AU)

O objetivo deste estudo foi investigar a associação entre infecção crônica por Anaplasma marginale e Babesia spp. e parâmetros hematológicos de novilhas taurinas prenhes e não prenhes. Sangue de 94 fêmeas foi coletado no primeiro dia (D-10) do protocolo de inseminação artificial em tempo fixo (IATF) e no diagnóstico de gestação (D+34). Parâmetros hematológicos foram comparados entre novilhas prenhes (PG) e não prenhes (NPG) e dentro dos grupos entre dias de coleta. Usando-se PCR em tempo real (qPCR), determinou-se a infecção por A. marginale e Babesia bovis e quantificação absoluta de Babesia spp. Entre os grupos PG e NPG. A análise de correlação foi realizada entre o número de cópias (CN) de Babesia spp. e parâmetros hematológicos. No D-10, a concentração de hemoglobina foi maior para NPG e hematócrito, e proteína plasmática total foram maiores em D+34 para ambos os grupos. Não houve diferença para CN de Babesia spp. entre os grupos. Na primeira qPCR, todas as novilhas foram positivas para A. marginale e B. bovis. Correlações significativas foram encontradas entre hemoglobina/eritrócito e hemoglobina/hematócrito (r=0,8082 e r=0,3009, respectivamente). Baixos níveis de A. marginale e Babesia spp. não afetaram os parâmetros hematológicos de novilhas taurinas prenhes e não prenhes cronicamente infectadas.(AU)

Local regulation of antral follicle development and ovulation in monovulatory species

The identification of mutations in the genes encoding bone morphogenetic protein 15 (BMP15) and growth and differentiation factor 9 (GDF9) associated with phenotypes of sterility or increased ovulation rate in sheep aroused interest in the study of the role of local factors in preantral and antral folliculogenesis in different species. An additive mutation in the BMP15 receptor, BMPR1b, which determines an increase in the ovulatory rate, has been introduced in several sheep breeds to increase the number of lambs born. Although these mutations indicate extremely relevant functions of these factors, the literature data on the regulation of the expression and function of these proteins and their receptors are very controversial, possibly due to differences in experimental models. The present review discusses the published data and preliminary results obtained by our group on the participation of local factors in the selection of the dominant follicle, ovulation, and follicular atresia in cattle, focusing on transforming growth factors beta and their receptors. The study of the expression pattern and the functionality of proteins produced by follicular cells and their receptors will allow increasing the knowledge about this local system, known to be involved in ovarian physiopathology and with the potential to promote contraception or increase the ovulation rate in mammals.(AU)

Paraoxonase 1 activity in the sperm-rich portion of boar ejaculates is positively associated with sperm quality

Associations of the activity of the paraoxonase 1 (PON1) enzyme with boar sperm quality still needs to be characterized, since boar ejaculates present distinct portions with differences in sperm concentration and quality. This study evaluated PON1 activity in the serum, in the distinct portions of boar ejaculates and estimated correlations with sperm quality parameters. Ejaculates and blood samples were collected from six boars for three weeks (two per week per boar; n = 36). Serum and post-spermatic portion PON1 activities were positively correlated (P = 0.01) but were both uncorrelated with the PON1 activity in the sperm-rich portion and in the whole ejaculate (P > 0.05). Differences in PON1 activity among boars were only observed in the sperm-rich portion of the ejaculate (P < 0.05). The PON1 activity in the serum and in the post-spermatic portion was generally negatively correlated with parameters of spermatozoa kinetics (P < 0.05). In the sperm-rich portion, PON1 activity was positively correlated with sperm concentration (P < 0.0001), curvilinear distance and velocity (both P < 0.05) and DNA integrity (P < 0.05), but negatively correlated with straightness and linearity (P < 0.05). Thus, boar ejaculates with increased PON1 activity in the sperm-rich portion may present increased concentration and spermatozoa with acceptable curvilinear velocity and distance and DNA integrity, which suggests that PON1 activity may be a biomarker for potential fertility.(AU)

Does combining estradiol cypionate and GnRH for ovulation induction in recipient cows increase pregnancy rate after timed embryo transfer?

Estradiol cypionate (EC) or GnRH have been widely used for ovulation induction in timed embryo transfer (TET). EC administration increases the proportion of cows that show estrus, whereas GnRH promotes more synchronized ovulations. The aim of the present study was to evaluate the potential beneficial effects of combining EC and GnRH in TET. In experiment 1, no difference was observed on serum progesterone concentrations on Day 6 and 13 after GnRH treatment between GnRH and EC+GnRH groups. In experiment 2, pregnancy per embryo transfer (P/ET) did not differ (p = 0.69) between GnRH (62.8%) and EC+GnRH (58.7%) groups. In conclusion, combining EC and GnRH for ovulation induction does not increase progesterone secretion and pregnancy rate after TET in cattle.(AU)

Participação de membros da superfamília TGF beta na foliculogênese, luteinização e luteólise / Role of TGF-beta superfamily members during folliculogenesis, luteinization and luteolysis

Fatores produzidos no ovário como os membros da família dos fatores de crescimento transformantes beta (TGFβ) e seus receptores, são essenciais durante o desenvolvimento folicular. Membros desta superfamília desempenham papel chave na fertilidade e diferenças espécie-específicas na regulação desses fatores têm sido descritas, envolvendo as funções ovarianas em condições fisiológicas ou patológicas. A proteína morfogenética óssea 15 (BMP15) e o fator de crescimento e diferenciação 9 (GDF9) destacam-se, pois desempenham papéis importantes na regulação do crescimento e da diferenciação folicular. Ainda, há evidências de que outras BMPs, ativinas, inibinas e seus receptores também possam estar envolvidos no controle da foliculogênese, ovulação/luteinização e luteólise. A maioria dos dados demostram que os TGFs atuam regulando negativamente a síntese de progesterona, o que sugere envolvimento na inibição da luteinização e promoção da luteólise. O avanço no entendimento das funções destes fatores locais poderá possibilitar o desenvolvimento tanto de novas estratégias contraceptivas, como também para controle do ciclo estral ou menstrual.

Factors produced in the ovary, such as transforming growth factors beta members (TGFβ) and their receptors, play a key role during follicular development. Members from this family have an important role in female fertility and species-specific differences in their regulation have been described, being involved in ovarian function regulation under both physiological and pathological conditions. Bone morphogenetic protein 15 (BMP15) and growth and differentiation factor 9 (GDF9) are the most studied factors due to their involvement in the regulation of follicular development and differentiation. Besides BMP15 and GDF9, other BMPs, activins, inhibins and their receptors may be involved in the control of folliculogenesis, ovulation/luteinization and luteolysis. Most studies demonstrate that TGFβ members negatively regulate progesterone synthesis, suggesting an involvement in luteolysis. The advance in the knowledge of the function of these local factors may allow the development of new contraceptive strategies as well as new approaches to control the estrous or menstrual cycle.

Participação de membros da superfamília TGF beta na foliculogênese, luteinização e luteólise / Role of TGF-beta superfamily members during folliculogenesis, luteinization and luteolysis

Fatores produzidos no ovário como os membros da família dos fatores de crescimento transformantes beta (TGFβ) e seus receptores, são essenciais durante o desenvolvimento folicular. Membros desta superfamília desempenham papel chave na fertilidade e diferenças espécie-específicas na regulação desses fatores têm sido descritas, envolvendo as funções ovarianas em condições fisiológicas ou patológicas. A proteína morfogenética óssea 15 (BMP15) e o fator de crescimento e diferenciação 9 (GDF9) destacam-se, pois desempenham papéis importantes na regulação do crescimento e da diferenciação folicular. Ainda, há evidências de que outras BMPs, ativinas, inibinas e seus receptores também possam estar envolvidos no controle da foliculogênese, ovulação/luteinização e luteólise. A maioria dos dados demostram que os TGFs atuam regulando negativamente a síntese de progesterona, o que sugere envolvimento na inibição da luteinização e promoção da luteólise. O avanço no entendimento das funções destes fatores locais poderá possibilitar o desenvolvimento tanto de novas estratégias contraceptivas, como também para controle do ciclo estral ou menstrual.(AU)

Factors produced in the ovary, such as transforming growth factors beta members (TGFβ) and their receptors, play a key role during follicular development. Members from this family have an important role in female fertility and species-specific differences in their regulation have been described, being involved in ovarian function regulation under both physiological and pathological conditions. Bone morphogenetic protein 15 (BMP15) and growth and differentiation factor 9 (GDF9) are the most studied factors due to their involvement in the regulation of follicular development and differentiation. Besides BMP15 and GDF9, other BMPs, activins, inhibins and their receptors may be involved in the control of folliculogenesis, ovulation/luteinization and luteolysis. Most studies demonstrate that TGFβ members negatively regulate progesterone synthesis, suggesting an involvement in luteolysis. The advance in the knowledge of the function of these local factors may allow the development of new contraceptive strategies as well as new approaches to control the estrous or menstrual cycle.(AU)

Effect of recombinant bovine somatotropin (rbST) treatment on follicular population and development in non-lactating dairy cows

The aim of this study was to evaluate the long-term effects of recombinant bovine somatotropin (rbST) on follicle population and ovulatory follicle development in non-lactating dairy cows. Twenty-one Jersey cows were allocated in rbST (n=11) or control (n=10) groups. On day -60, cows in rbST group received 500 mg of somatotropin (s.c. Lactotropin®, Elanco). On day 0, control and rbST cows received an intravaginal progesterone-releasing device (1.9 g, CIDR®, Zoetis) and GnRH (100 mg, IM, Factrel®, Zoetis). On day 8, cows received PGF2α (25 mg, IM, Lutalyse®, Zoetis) and the CIDR® was removed. Twelve hours after device removal (D8), serum, follicular fluid and granulosa cells samples were collected. Serum and follicular concentration of estradiol (E2) and progesterone (P4) were analyzed. Total RNA was extracted from granulosa cells to measure gene expression of LHCGR, STAR, HSD-3B1, CYP11A1, CYP19A1, CYP17A1, IGFR and PAPPA by real-time PCR. Ultrasonography was performed on days -60, -53, -46, -14, -7, 0 and 8 for antral follicle count. Results were analyzed by repeated measures ANOVA and t-test. There was no effect of rbST treatment on the number of follicles during the 60 days period, as well as no effect on serum and follicular fluid E2 and follicular fluid P4 at the moment of follicle aspiration. There was a reduction in PAPPA (P = 0.006), CYP11A1 (P = 0.04) and CYP19A1 (P = 0.002) mRNA levels in granulosa cells of the pre-ovulatory follicle of rbST treated cows. In conclusion, a single dose of rbST did not have long-term effects on antral follicle population, serum and follicular E2/P4 concentrations in non-lactating dairy cows. Despite that, rbST injection decreased granulosa cell expression of genes related to steroidogenesis in the pre-ovulatory follicle.

Effect of recombinant bovine somatotropin (rbST) treatment on follicular population and development in non-lactating dairy cows

The aim of this study was to evaluate the long-term effects of recombinant bovine somatotropin (rbST) on follicle population and ovulatory follicle development in non-lactating dairy cows. Twenty-one Jersey cows were allocated in rbST (n=11) or control (n=10) groups. On day -60, cows in rbST group received 500 mg of somatotropin (s.c. Lactotropin®, Elanco). On day 0, control and rbST cows received an intravaginal progesterone-releasing device (1.9 g, CIDR®, Zoetis) and GnRH (100 mg, IM, Factrel®, Zoetis). On day 8, cows received PGF2α (25 mg, IM, Lutalyse®, Zoetis) and the CIDR® was removed. Twelve hours after device removal (D8), serum, follicular fluid and granulosa cells samples were collected. Serum and follicular concentration of estradiol (E2) and progesterone (P4) were analyzed. Total RNA was extracted from granulosa cells to measure gene expression of LHCGR, STAR, HSD-3B1, CYP11A1, CYP19A1, CYP17A1, IGFR and PAPPA by real-time PCR. Ultrasonography was performed on days -60, -53, -46, -14, -7, 0 and 8 for antral follicle count. Results were analyzed by repeated measures ANOVA and t-test. There was no effect of rbST treatment on the number of follicles during the 60 days period, as well as no effect on serum and follicular fluid E2 and follicular fluid P4 at the moment of follicle aspiration. There was a reduction in PAPPA (P = 0.006), CYP11A1 (P = 0.04) and CYP19A1 (P = 0.002) mRNA levels in granulosa cells of the pre-ovulatory follicle of rbST treated cows. In conclusion, a single dose of rbST did not have long-term effects on antral follicle population, serum and follicular E2/P4 concentrations in non-lactating dairy cows. Despite that, rbST injection decreased granulosa cell expression of genes related to steroidogenesis in the pre-ovulatory follicle.(AU)

Transforming growth factor-beta family members are regulated during induced luteolysis in cattle

The transforming growth factors beta (TGFβ) are local factors produced by ovarian cells which, after binding to their receptors, regulate follicular deviation and ovulation. However, their regulation and function during corpus luteum (CL) regression has been poorly investigated. The present study evaluated the mRNA regulation of some TGFβ family ligands and their receptors in the bovine CL during induced luteolysis in vivo. On day 10 of the estrous cycle, cows received an injection of prostaglandin F2α (PGF) and luteal samples were obtained from separate groups of cows (n= 4-5 cows per time-point) at 0, 2, 12, 24 or 48 h after treatment. Since TGF beta family comprises more than 30 ligands, we focused in some candidates genes such as activin receptors (ACVR-1A, -1B, -2A, -2B) AMH, AMHR2, BMPs (BMP-1, -2, -3, -4, -6 and -7), BMP receptors (BMPR-1A, -1B and -2), inhibin subunits (INH-A, -BA, -BB) and betaglycan (TGFBR3). The mRNA levels of BMP4, BMP6 and INHBA were higher at 2 h after PGF administration (P<0.05) in comparison to 0 h. The relative mRNA abundance of BMP1, BMP2, BMP3, BMP4, BMP6, ACVR1B, INHBA and INHBB was upregulated up to 12 h post PGF (P<0.05). On the other hand, TGFBR3 mRNA that codes for a reservoir of ligands that bind to TGF-beta receptors, was lower at 48 h. In conclusion, findings from this study demonstrated that genes encoding several TGFβ family members are expressed in a time-specific manner after PGF administration.

Transforming growth factor-beta family members are regulated during induced luteolysis in cattle

The transforming growth factors beta (TGFβ) are local factors produced by ovarian cells which, after binding to their receptors, regulate follicular deviation and ovulation. However, their regulation and function during corpus luteum (CL) regression has been poorly investigated. The present study evaluated the mRNA regulation of some TGFβ family ligands and their receptors in the bovine CL during induced luteolysis in vivo. On day 10 of the estrous cycle, cows received an injection of prostaglandin F2α (PGF) and luteal samples were obtained from separate groups of cows (n= 4-5 cows per time-point) at 0, 2, 12, 24 or 48 h after treatment. Since TGF beta family comprises more than 30 ligands, we focused in some candidates genes such as activin receptors (ACVR-1A, -1B, -2A, -2B) AMH, AMHR2, BMPs (BMP-1, -2, -3, -4, -6 and -7), BMP receptors (BMPR-1A, -1B and -2), inhibin subunits (INH-A, -BA, -BB) and betaglycan (TGFBR3). The mRNA levels of BMP4, BMP6 and INHBA were higher at 2 h after PGF administration (P<0.05) in comparison to 0 h. The relative mRNA abundance of BMP1, BMP2, BMP3, BMP4, BMP6, ACVR1B, INHBA and INHBB was upregulated up to 12 h post PGF (P<0.05). On the other hand, TGFBR3 mRNA that codes for a reservoir of ligands that bind to TGF-beta receptors, was lower at 48 h. In conclusion, findings from this study demonstrated that genes encoding several TGFβ family members are expressed in a time-specific manner after PGF administration.(AU)

Systemic inflammatory and stress markers in cattle and sheep submitted to different reproductive procedures / Marcadores sistêmicos de inflamação e estresse em bovinos e ovinos submetidos a diferentes procedimentos reprodutivos

Previous studies have evaluated the effects of different reproductive procedures on discomfort markers in sheep and cattle. Such studies may help stimulate the adoption of techniques that are more beneficial for animal welfare. However, markers that are commonly used to evaluate discomfort are highly influenced by external factors. To overcome this, several systemic markers can be evaluated to more precisely identify stress, pain, and inflammation. Such markers include cortisol, acute phase proteins, bradykinin, and substance P. We aimed to review the potential markers of stress, pain, and inflammation, and discuss how and when they are regulated after different stimuli related to reproductive procedures in cattle and sheep. Furthermore, we aimed to review how reproductive procedures with different degrees of invasiveness cause stress and provide information that may help develop strategies to limit animal discomfort.(AU)

Estudos anteriores avaliaram o efeito de diferentes procedimentos reprodutivos sobre marcadores de desconforto em bovinos e ovinos. Tais estudos podem estimular a adoção de técnicas que preservem o bem-estar animal. Entretanto, os marcadores comumente utilizados apresentam alta influência de fatores externos. Para contornar isso, a avaliação conjunta de diferentes parâmetros sistêmicos pode ser utilizada para determinar com maior precisão a presença de estresse, dor ou inflamação, como cortisol, proteínas de fase aguda, a bradicinina e a substância P. O objetivo desta revisão é relacionar potenciais marcadores de inflamação e estresse, discutindo como e quando são regulados frente aos estímulos em bovinos e ovinos. Ainda, pretende-se revisar de que forma procedimentos reprodutivos com diferentes graus de invasividade acarretam em desconforto, fornecendo informações para a elaboração de estratégias que possibilitem minimizá-lo.(AU)

Systemic inflammatory and stress markers in cattle and sheep submitted to different reproductive procedures / Marcadores sistêmicos de inflamação e estresse em bovinos e ovinos submetidos a diferentes procedimentos reprodutivos

ABSTRACT: Previous studies have evaluated the effects of different reproductive procedures on discomfort markers in sheep and cattle. Such studies may help stimulate the adoption of techniques that are more beneficial for animal welfare. However, markers that are commonly used to evaluate discomfort are highly influenced by external factors. To overcome this, several systemic markers can be evaluated to more precisely identify stress, pain, and inflammation. Such markers include cortisol, acute phase proteins, bradykinin, and substance P. We aimed to review the potential markers of stress, pain, and inflammation, and discuss how and when they are regulated after different stimuli related to reproductive procedures in cattle and sheep. Furthermore, we aimed to review how reproductive procedures with different degrees of invasiveness cause stress and provide information that may help develop strategies to limit animal discomfort.

RESUMO: Estudos anteriores avaliaram o efeito de diferentes procedimentos reprodutivos sobre marcadores de desconforto em bovinos e ovinos. Tais estudos podem estimular a adoção de técnicas que preservem o bem-estar animal. Entretanto, os marcadores comumente utilizados apresentam alta influência de fatores externos. Para contornar isso, a avaliação conjunta de diferentes parâmetros sistêmicos pode ser utilizada para determinar com maior precisão a presença de estresse, dor ou inflamação, como cortisol, proteínas de fase aguda, a bradicinina e a substância P. O objetivo desta revisão é relacionar potenciais marcadores de inflamação e estresse, discutindo como e quando são regulados frente aos estímulos em bovinos e ovinos. Ainda, pretende-se revisar de que forma procedimentos reprodutivos com diferentes graus de invasividade acarretam em desconforto, fornecendo informações para a elaboração de estratégias que possibilitem minimizá-lo.

Methods to study ovarian function in monovulatory species using the cow as a model

In this review, we discuss the utility of the cow as an in vivo model to study the regulation of ovarian functions in monovular species. It is increasingly becoming clear that besides endocrine control locally produced factors play pivotal roles during dominant follicle selection, oocyte maturation, ovulation and luteolysis. Although in vitro culture systems have been used to study these processes, definitive understanding the interactions between endocrine and local factors requires appropriate in vivo models. Most of the experimental approaches to study ovarian functionsin vivo in large animals are based on the use of ultrasonography and considerable progress in this field has been made during the last thirty years. It has been shown that cows are an excellent model to collect samples (e.g., follicular fluid, granulosa cells, oocytes) from live animals at specific stages of follicular development in order to study mechanisms of intrafollicular factors in a physiological endocrine environment. In addition to support fundamental studies, the cow model has contributed immensely to the refinement of assisted reproductive technologies, which are now widely used not only in farm animals but also in humans.