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A produção de leite tem sido um dos principais pilares de sustentação das famílias no meio rural. Contudo, a falta de gestão e de sucessão familiar têm sido temas recorrentes no debate sobre os entraves ao fortalecimento da agricultura familiar, principalmente na atividade leiteira. Neste contexto, este trabalho teve como objetivo sistematizar e relatar a experiência de uma família de produtores de leite. O estudo foi realizado em uma propriedade rural, a Agropecuária Zambiasi, localizada no município de Coqueiros do Sul, na região Norte do estado do Rio Grande do Sul. Para coleta das informações, foi realizada entrevista com a família, utilizado um roteiro semiestruturado, desenvolvido na disciplina de Gestão da Propriedade Rural, do Curso de Mestrado Profissional em Desenvolvimento Rural da Universidade de Cruz Alta. Pode-se dizer que, a gestão compartilhada, o controle dos indicadores zootécnicos e econômicos o incentivo ao estudo dos sucessores e a remuneração pelo seu trabalho, têm garantido a sustentabilidade da Agropecuária Zambiasi.

This study aimed to determine the frequency and distribution of infectious diseases diagnosed through necropsy examination and histopathological analysis in growing/finishing pigs along 12 years (2005-2016) in Southern Brazil. We evaluated 1906 anatomopathological exams of pigs at growing/finishing phases, of which the infectious diseases corresponded to 75.6% of the cases (1,441/1,906). Porcine circovirus type 2 (PCV2) infections were the most frequent, accounting for 51.3% of the cases (739/1,441) with a higher frequency from 2005 to 2007, characterizing an epidemic distribution, with a gradual decline after 2008. Infectious diseases affecting the respiratory system were the second major cause with 30.1% of the cases. Among these, necrotizing bronchiolitis caused by swine Influenza (15.1%, 218/1,441) and bacterial pneumonia (15%, 216/1,441) were the main conditions. Influenza was mostly diagnosed from 2010 to 2013, accounting for 43.1% (167/387) of the cases. After this period, both respiratory infectious diseases were endemic. Digestive system infectious diseases accounted for 10.5% of the diagnoses (151/1,441), with the following main conditions: Salmonella spp. enterocolitis (43.7%, 66/151), Lawsonia spp. proliferative enteropathy (41.7%, 63/151), and Brachyspira spp. colitis (14.6%, 22/151). The latter had a higher incidence from 2012 to 2014 with all cases detected in this period. Polyserositis and bacterial meningitis represented, respectively, 5.8% (84/1,441) and 2.3% (33/1,441) of the cases diagnosed, with a constant endemic character. RESUMO: O objetivo deste estudo consistiu em determinar a frequência e a distribuição das doenças infecciosas diagnosticadas através de exame de necropsia e análise histopatológica em suínos nas fases de crescimento/terminação ao longo de 12 anos (2005-2016) no sul do Brasil. Foram avaliados 1906 laudos anatomopatológicos de suínos nas fases de crescimento/terminação, dos quais as doenças infecciosas corresponderam a 75,6% (1441/1906) do total. As infecções por circovírus suíno tipo 2 (PCV2) foram as mais frequentes, contabilizando 51,3% (739/1441) dos casos, com uma alta frequência de 2005 a 2007 caracterizando uma distribuição epidêmica neste período, e um declínio gradual após o ano de 2008. A segunda principal causa incluiu as doenças infecciosas que afetam o sistema respiratório (30,1% dos casos). Dentre essas, destacaram-se a influenza suína (15,1%; 218/1441) e pneumonias bacterianas (15%; 216/1441). O diagnóstico de influenza apresentou uma frequência elevada de 2010 a 2013, totalizando 43,1% (167/387) dos casos. Após este período, ambas doenças infecciosas respiratórias exibiram caráter endêmico. As doenças infecciosas do sistema digestório totalizaram 10,5% (151/1441) dos diagnósticos, com as seguintes principais condições: enterocolite por Salmonella spp. (43,7%; 66/151), enteropatia proliferativa por Lawsonia spp. (41,7%; 63/151) e colite por Brachyspira spp. (14,6%; 22/151). A colite por Brachyspira spp. apresentou uma alta incidência de 2012 a 2014 com todos os casos detectados no período. As polisserosites e meningites bacterianas representaram 5,8% (84/1441) e 2,3% (33/1441) dos casos diagnosticados, respectivamente, com um caráter endêmico constante.

As dificuldades são características comuns no cotidiano das pessoas, na atividade leiteira e na sucessão familiar não é diferente. Frente aos diversos entraves que podem ser encontrados no meio rural, este estudo buscou analisar as dificuldades dos jovens em relação à atividade leiteira, seus propósitos de vida, e suas estratégias de permanência na propriedade rural. Como metodologia foi usada uma pesquisa exploratória e descritiva, com coleta de dados qualitativos e quantitativos, com a participação de 82 jovens filhos de produtores rurais, residentes em estabelecimentos rurais produtores de leite, no estado do Rio Grande do Sul. O estudo apontou que, para os jovens, a maior dificuldade encontrada na atividade leiteira está relacionada ao preço recebido pelo leite e aos custos de produção. Sendo que, os principais objetivos destes jovens estão voltados a continuidade da atividade e do trabalho dos pais, enfatizando o aumento e melhorias na produção leiteira, lucratividade e rentabilidade. Assim, seus propósitos de vida, são de suceder os pais na atividade leiteira, ampliando a produção, a gestão e a sua formação, contribuindo com o desenvolvimento no meio rural.

O mastocitoma cutâneo e uma neoplasia originada a partir da proliferacao desordenada de mastocitos, sendo altamente infiltrativo no subcutâneo e na derme. Em gatos representa 12 a 20% dos tumores de pele. No entanto, relatos de casos desse tumor no Brasil sao raros. O objetivo deste trabalho e descrever aspectos clinicos, citologicos e hematologicos de mastocitoma cutâneo em um felino femea, sem raca definida, pesando 2,7 kg, com 3 anos de idade, atendido no Hospital Veterinario da Universidade de Cruz Alta com historico de que a cerca de 6 meses apresentou aumento de volume progressivo acima do olho direito. Ao exame fisico foi evidenciado mucosas coradas, temperatura normal, tempo de preenchimento capilar < 2 segundos e nodulo solitario, bem circunscrito, nao ulcerado, de consistencia firme e de aproximadamente 5 cm na face. Apos a realizacao de citologia aspirativa por agulha fina foi obtido o diagnostico de mastocitoma cutâneo. A partir da citologia esse tumor e classificado na categoria de neoplasias de celulas redondas, juntamente com o linfoma, tumor venereo transmissivel, entre outros, por isso estes devem ser inclusos como diagnostico diferencial. Nesse contexto, os exames laboratoriais desempenham importante papel no diagnostico da doenca e monitoramento da saude do paciente.

Endometritis is an inflammation of the endometrium associated with bacterial infection. The pathogenesis of endometritis in cows is still not completely understood. The combined analysis of the markers of inflammation and oxidative stress has contributed to a better understanding of disease mechanisms, but is still unexplored in uterine disorders. Moreover, research provides evidence about an important role of the vagus nerve in regulating the innate immune function through the cholinergic anti-inflammatory pathway in response to bacterial infections. This new pathway has demonstrated a critical role in controlling the inflammatory system. The aim of this study was to evaluate the activity of cholinesterase in total blood, lymphocytes, and serum of dairy cows with clinical and subclinical endometritis. Sixty-one Holstein cows, between 30 and 45 days in milk, were classified into 3 groups of animals: presenting clinical endometritis (n = 22), subclinical endometritis (n = 17), and healthy (n = 22). Mean leukocyte counts did not differ among groups, but the neutrophil number was significantly higher in cows with clinical endometritis than those in healthy animals. Also, serum concentration of interleukin-1beta (pg/mL) was significantly higher in cows with endometritis. The activity of acetylcholinesterase in blood and lymphocytes increased in both groups with endometritis. Animals with endometritis presented an increase in lipid peroxidation, but the antioxidant enzyme activity (catalase levels) was higher in endometritis groups than in normal cows. In conclusion, the inflammatory process of clinical and subclinical endometritis leads to systemic lipid peroxidation despite the compensatory increase of the antioxidant enzyme. These data also provide evidence of an important role of the cholinergic pathway in regulating dairy cows with clinical and subclinical endometritis.

The present study aimed to evaluate the effects of a strategic feeding supplementation protocol on reproductive and economic results of exclusively fixed timed artificial inseminated (FTAI) beef cows from a southern Brazilian herd. The experiment was carried out over 2 consecutive breeding seasons (2016 and 2017, from October to January). Two-hundred, 3 and 4 years old, non-suckled, Angus cows (n=100/year), were divided into two homogeneous groups (by weight and body condition score) 25 days before the first FTAI of the breeding season (First FTAI=Day 0). As a representation of traditional management of herds grazing on natural pastures from Rio Grande do Sul Province, Brazil, cows from control group (CG; n=100; 50 cows in each year) received basic mineral supplementation (without protein an energy) ad libitum during the entire experimental period. As an alternative feeding protocol, supplemented group (SG; n=100; 50 in each year) received a mineral supplementation enriched with protein (23%), energy (44% NDT) and sodium monensin (0.25%) ad libitum from days: –25 to 80 of breeding season. Cows were maintained in 2 separated paddocks of native pasture with similar forage composition and availability. All cows were submitted to a progesterone/estradiol-based estrus synchronization protocol on day -10, and cows not pregnant at diagnosis were resynchronized on days 28 and 76 using the same hormonal treatment. There was no year effect (P>0.1) on weight gain and reproductive results, data from both breeding seasons were polled together for further analyzes. Cows from SG presented higher average daily weight gain and gained more weight than cows from CG (p0.1). Cows from SG became pregnant earlier (p

This experiment aims to evaluate the correlation between lipid peroxidation levels in serum and seminal plasma in equines. Also, it investigates the lipid peroxidation in extended semen samples and its effects and sperm motility during a 72 hr refrigeration period. Blood and semen were collected from fertile Crioulo stallions. Serum and seminal plasma lipid peroxidation levels were analyzed by thiobarbituric acid reactive substances (TBARS) immediately after semen collection. After addition of extender (hour = 0), diluted semen was refrigerated and stored at 5 °C. Semen analyses, TBARS and catalase activity were performed in extended semen at 0, 24, 48, and 72 hours. We noted that levels of plasma lipid peroxidation can be used as an indicative of seminal oxidative stress. Also, lipid peroxidation does not increase substantially during semen storage. Lipid peroxidation and the antioxidant enzyme catalase do not seem to be the major cause of loss and motility and consequently reduction in fertility in stallion semen during storage for 72 h at 5 °C.

The potent activity against Trypanosomes and health beneficial effects of curcumin (Cur) has been demonstrated in various experimental models. In this study, we evaluated the in vivo effect of Cur as trypanocide and as potential anti-inflammatory agent, through the evaluation of immunomodulatory mechanisms in rats infected with Trypanosoma evansi. Daily oral Cur was administered at doses of 0, 20 or 60mg/kg as preventive treatment (30 and 15days pre infection) and as treatment (post infection). The treatment of the groups continued until the day of euthanasia. Fifteen days after inoculation, parasitemia, plasma proinflammatory cytokines (IFN-γ, TNF-α, IL-1, IL-6), anti-inflammatory cytokines (IL-10) and blood acetylcholinesterase activity (AChE) were analyzed. Pretreatment with Cur reduced parasitemia and lethality. Cur inhibited AChE activity and improved immunological response by cytokines proinflammatory, fundamental during T. evansi infection. We found that Cur is not so important as an antitrypanosomal activity but as immunomodulator agent. These findings reveal that the preventive use of Cur stimulates anti-inflammatory mechanisms, reducing an excessive inflammatory response.

Made available in DSpace on 2013-09-27T14:54:28Z (GMT). No. of bitstreams: 1 WOS000304231600006.pdf: 4200149 bytes, checksum: da68c3a014ed77979dfeca212097e21a (MD5) Previous issue date: 2012-06-01 Made available in DSpace on 2013-09-30T18:37:40Z (GMT). No. of bitstreams: 1 WOS000304231600006.pdf: 4200149 bytes, checksum: da68c3a014ed77979dfeca212097e21a (MD5) Previous issue date: 2012-06-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:50:02Z No. of bitstreams: 1 WOS000304231600006.pdf: 4200149 bytes, checksum: da68c3a014ed77979dfeca212097e21a (MD5) Made available in DSpace on 2014-05-20T13:50:02Z (GMT). No. of bitstreams: 1 WOS000304231600006.pdf: 4200149 bytes, checksum: da68c3a014ed77979dfeca212097e21a (MD5) Previous issue date: 2012-06-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Oocyte meiotic resumption is triggered by the ovulatory gonadotropin surge; in cattle, angiotensin II (AngII) and prostaglandins (PG) are key mediators of this gonadotropin-induced event. Here, we tested the hypothesis that progesterone (P-4) is also involved in oocyte meiotic resumption induced by the gonadotropin surge. In Experiment I, P-4 induced nuclear maturation in a dose-dependent manner using a coculture of follicular hemisections and cumulus-oocyte complexes. In the second experiment, using an in vivo model, an injection of mifepristone (MIFE; P-4 receptor antagonist) at the antrum of preovulatory follicles prevented GnRH-induced oocyte meiotic resumption in vivo. In Experiment III (coculture system similar to that of Experiment I), MIFE prevented stimulatory effects of AngII on resumption of meiosis, but saralasin (AngII receptor antagonist) did not inhibit P-4 actions. In Experiments IV and V, fibroblast growth Factor 10 (FGF10; known to suppress steroidogenesis in granulosa cells), blocked AngII-but not P-4-induced oocyte meiotic resumption. Therefore, we inferred that AngII is upstream to P-4 in a cascade to induce meiotic resumption. Previously, we had reported that AngII acted throughout the PGs pathway to modulate nuclear progression. In Experiment V, indomethacin inhibited resumption of meiosis induced by P-4, providing further support to the AngII-P-4, sequential effect on meiotic resumption. In conclusion, we inferred that AngII, P-4, and PGs are sequential steps in the same pathway that culminates with bovine oocyte maturation. (C) 2012 Elsevier B.V. All rights reserved. Universidade Federal de Santa Maria (UFSM), Lab Biotechnol & Anim Reprod BioRep, BR-97119900 Santa Maria, RS, Brazil State Univ São Paulo UNESP, Dept Physiol, Botucatu, SP, Brazil State Univ São Paulo UNESP, Dept Physiol, Botucatu, SP, Brazil

The objective of this study was to characterize the profiles of Ang-(1-7), MAS receptor, ACE2, NEP and PEP during the ovulatory process in cattle. For this study, 40 synchronized cows with follicular diameter ≥ 12 mm were ovariectomized at different time-points (0, 3, 6, 12 and 24 h) after i.m. application of gonadotropin-releasing hormone (GnRH) to induce a luteinizing hormone surge. Follicular fluid was collected for measuring Ang-(1-7) by radioimmunoassay. Theca and granulosa cells were isolated from the preovulatory follicles to evaluate the gene expression of MAS receptor, ACE2, NEP and PEP by qRT-PCR assay. Cross-contamination between theca and granulosa cells was tested by RT-PCR to detect cytochrome P450 aromatase (CYP19A1) and 17α-hydroxylase (CYP17A1) mRNA. Ang-(1-7) levels were constant until 12 h and then increased ( p < 0.05) at 24 h after GnRH. Messenger RNA expression of MAS, ACE2, NEP and PEP was detected in theca and granulosa cells at all time-points after GnRH. In granulosa cells, ACE2, NEP and PEP were differentially expressed after GnRH treatment ( p < 0.05). In conclusion, the Ang-(1-7), MAS receptor, ACE2, NEP and PEP profiles in preovulatory follicles indicate that Ang-(1-7) plays a role in the regulation of the ovulatory process in cattle.

The present study evaluates levels of aflatoxin contamination involving small dairy farms from the in the Northwest region of Rio Grande do Sul, Brazil. The objectives of this trial is: quantify lactating cow diet and raw for bulk milk Aflatoxin B1 (AFB1) contamination; evaluate the use of a mycotoxin adsorbent on cows submitted to semi-confinement raising; and verify the presence of AFM1 contamination on UHT and powdered milk commercialized locally. For this, 17 farms were selected. During the experimental period, every lactating cow on each herd received 50 g/day of a commercial mycotoxin adsorbent for dairy cows (100% bentonite). From each farm, bulk milk, corn silage and concentrate samples were collected for aflatoxin quantification. Aflatoxin M1 was detected in all milk samples examined from each farm, but the levels were within the allowed by the legislation. Aflatoxin B1 was also detected in all samples of corn silage and concentrate. The mycotoxin adsorbent used reduced (p < 0.05) AFM1 contamination in milk. AFM1 milk contamination levels observed on commercialized milk also respected Brazilian requirements. It is possible to conclude that there is a high incidence of Aflatoxin B1 contamination on corn silage and dairy cows concentrates in family farms from South Brazil region. Based on the condition in which the present study was conducted, the use of a mycotoxin adsorbent reduced the levels of AFM in milk in production system. However, the locally produced milk and commercial milk were below the AFM levels accepted by the National Requirements for AFM1 contamination.

The aim of this study was to evaluate cholinesterase activity during the early acute phase of Trypanosoma evansi infection in rats. Fifteen male Wistar rats were randomly distributed into three groups ( n = 5 animals per group): two trypanosome-infected groups (T3 and T5) and uninfected controls (C). The animals were inoculated intraperitoneally with 10 6 trypanosomes. The blood was collected by cardiac puncture on the 3rd (T3) or 5th day post-infection (T5 and C). Cerebrum and cerebellum were removed for the evaluation of acetylcholinesterase (AChE) activity. AChE activity was also evaluated in whole blood and butyrylcholinesterase activity (BUChE) in plasma samples. Parasitemia were progressive increase and parasites were observed in the peripheral blood of all infected animals one day post-inoculation. AChE activity was not altered in cerebrum and cerebellum tissues. AChE activity in blood significantly decreased in the T3 and T5 groups (26.63 and 25.86 mU/l mol Hb) compared with the control (37.84 mU/l mol Hb). In addition BUChE activity in plasma was lower in the T3 (7.01 μmol BTC hydrolyzed/h/mL) than the T5 and C groups (9.84 and 12.00 μmol BTC hydrolyzed/h/mL). This study therefore, shows that reductions in the activity of cholinesterase occur in acute infection by T. evansi in rats and this demonstrates an important change occurring in animals infected by the protozoan and may indicate a potential role the enzymes play in the mechanism of disease.

The objective was to evaluate the effect of estradiol benzoate (EB), in association with three progestin protocols, on ovarian follicular regression of suckled beef cows treated at three stages of follicular development (pre-deviation, deviation, or post-deviation). Thirty-six suckled beef cows (60–90 d postpartum, given 125 μg cloprostenol on two occassions, 12 h apart). Forty-eight hours after the first cloprostenol treatment, all follicles >5 mm were ablated and transrectal ultrasound scanning (8 MHz) was performed every 24 h until Day 7 (Day 0 = treatment). When the largest follicle reached a designated diameter of 5–7, 8–10 or >10 mm, cows were randomly allocated to receive 2 mg of EB im in association with an intravaginal device containing 250 mg of medroxyprogesterone acetate (MPA) with or without 100 mg of progesterone (P 4 ) given im, or an intravaginal device containing P 4 (3 × 3 factorial design). Treatments induced follicular regression in all cows, independent of follicular stage or treatment. There was no interaction between progestin treatment and follicular stage, nor was there any difference in the time of follicular regression or new wave emergence among follicular stages. Treatment with MPA plus P 4 delayed follicular regression. In conclusion, EB in association with various progestins induced regression of growing follicles and emergence of a new follicular wave in postpartum beef cows, regardless of the stage of follicular development.

Contents The aim of the present study was to examine the role of oxytocin (OT) in the progesterone (P4) and prostaglandins (PGs) pathway to induce oocyte meiotic resumption. Cumulus–oocyte complexes were co-cultured with follicular hemisections for 15 h to determine the effects of different doses of OT or atosiban (ATO; oxytocin receptor antagonist) on oocyte meiotic resumption. In another experiment, we examined the effect of the interaction between P4, OT and PGs on the regulatory cascade of the oocyte meiotic resumption. Oxytocin at 1 μm was effective in inducing meiotic resumption in oocytes co-cultured with follicular cells (84.0%), not differing from the positive control group (74.4%). Atosiban inhibited in a dose-dependent manner the positive effect of OT on the meiotic resumption (27.6% metaphase I with 10 μm of ATO, which did not differ from the 25.5% of the negative control group). Furthermore, a third experiment showed that P4 was able to induce oocyte meiotic resumption, which was inhibited by ATO. However, the OT positive effect was not blocked by mifepristone (P4 antagonist), but was inhibited by indomethacin (a non-selective PTGS2 inhibitor). Collectively, these data suggest a sequential role of P4, OT and PGs in the induction of oocyte meiotic resumption.

The aim of this study was to evaluate biochemical parameters of iron metabolism in rats experimentally infected with Trypanosoma evansi. To this end, 20 rats (Wistar) were intraperitoneally inoculated with blood containing trypomastigotes 10(6) (Group T) and 12 animals were used as negative control (Group C) and received saline (0.2 mL) through same route. Blood samples were collected by cardiac puncture on day 5 (C5, T5) and 30 (C30, T30) post-inoculation (pi) to perform complete blood count and determination of serum iron, transferrin, ferritin, total and latent iron fixation capacity, transferrin saturation and prohepcidin concentration. Also, bone marrow samples were collected, to perform Pearls staining reaction. Levels of iron, total and latent iron binding capacity and prohepcidin concentration were lower (P

The aim was to develop a timed artificial insemination (TAI) system in suckled beef cows. Cows (n=227), 60-80 days postpartum, received estradiol benzoate (5mg) and a vaginal device containing 250µg of medroxyprogesterone acetate (MPA; day 0). On day six, cloprostenol (125µg) and eCG (400IU) were administrated and calves were weaned for 88h. The devices were removed on day seven (BioRep group) or on day eight (TAI group). All cows of TAI group and cows of BioRep group that did not exhibit standing estrus received GnRH (100µg) on day 9. In experiment I, the follicular growth was monitored daily by transrectal ultrasound exams, from day 6 to day 9. The average size of the dominant follicle on day nine was 11.1±0.99mm (BioRep, n=7) and 11.5±0.65mm (TAI, n=7) and all animals ovulated. In experiment II, the BioRep group cows (n=106) were observed for estrous behavior after withdrawal of the device, twice a day for 48h, and inseminated 12h after detection. In the TAI group (n=107), the devices were withdrawn on day eight and after 24h these cows and those from the BioRep group, which were not stand in estrus, received 100µg of GnRH and TAI 16h later. The pregnancy rates were 57.6% (BioRep) and 52.3% (TAI). In conclusion, an increase on MPA exposure time did not affect the follicular dynamics and pregnancy rates and allow TAI without estrous observation. Furthermore, the treatment for eight days provides an efficient TAI system in suckled beef cows. O objetivo deste estudo foi desenvolver um protocolo de inseminação artificial com tempo fixo (IATF) em vacas de corte durante período de amamentação, avaliando o intervalo entre a retirada do progestágeno e a aplicação de GnRH sobre a dinâmica folicular e a prenhez. Para tanto, vacas (n=227) em pós-parto de 60 a 80 dias receberam benzoato de estradiol (5mg) e um pessário vaginal de acetato de medroxiprogesterona (250mg MAP; dia 0). No dia seis, os animais receberam cloprostenol sódico (125µg), gonadotrofina coriônica eqüina (400UI) e desmame temporário (88h). O MAP foi retirado no dia sete (Grupo BioRep) ou no dia oito (Grupo IATF). Todas as vacas do grupo TAI e aquelas que não manifestaram cio do grupo BioRep receberam GnRH (100µg) no dia nove. No experimento I, o monitoramento das estruturas ovarianas de 14 vacas foi realizado a cada 24h, desde o dia seis até 36h após a aplicação de GnRH em ambos os grupos. O tamanho médio do folículo dominante no dia nove foi de 11,1±0,99mm (BioRep n=7) e 11,5±0,65mm (IATF n=7) e todos os animais ovularam. No experimento II, no grupo BioRep (n=106), após a retirada do MAP, as fêmeas foram inseminadas com detecção de estro durante 48 horas. O restante dos animais do grupo BioRep e todos do grupo IATF (n=107) receberam 100µg de GnRH (dia nove) e IATF 16h depois. As taxas de prenhez foram de 57,6% (BioRep) e de 52,3% (IATF). O intervalo de 24h entre a retirada de MAP, mantido por oito dias, e a aplicação de GnRH não interfere na dinâmica folicular e na prenhez, permitindo inseminar vacas de corte amamentando sem observação de estro.

O objetivo do presente experimento foi investigar se a realização exclusiva da inseminação artificial em tempo fixo (IATF), empregando como indutor da ovulação o benzoato de estradiol (BE), proporciona taxas de prenhez semelhantes a uma associação de IA convencional e IATF com GnRH, em vacas de corte no pós-parto. Duzentos e cinqüenta vacas amamentado receberam um pessário vaginal contendo 250mg de acetato de medroxi-progesterona (MAP) e uma injeção intramuscular (IM) de 5mg de BE no dia 0. O pessário vaginal permaneceu por sete dias. No dia 6, foram aplicadas 400UI de gonadotrofina coriônica eqüina por via IM e 5mg de análogo de prostaglandina na submucosa vulvar, realizando nesse momento o desmame por 96h. Após a retirada dos pessários (dia 7), as vacas foram distribuídas em dois grupos. No grupo BioRep (n=150), as fêmeas foram observadas duas vezes por dia para detecção de estro por 48h e inseminadas 12h após sua manifestação. Os animais que não manifestaram estro nesse período receberam uma injeção IM de 100mg de GnRH, sendo submetidas à IATF, 16 a 18h após. No grupo BE (n=100), as vacas receberam uma injeção de 1mg de BE IM no dia 8 e foram inseminadas em tempo fixo no dia 9. A porcentagem de prenhez no grupo BioRep (54,7%) foi maior (P

O objetivo deste experimento foi comparar a eficiência de um programa hormonal associado ao desmame temporário por 96 horas na indução do estro e ovulação com o desmame definitivo aos 60 dias em vacas de corte. Foram utilizadas 183 vacas de corte amamentando, das raças Charolês (C), Nelore (N) e suas cruzas recíprocas, as quais foram genotipadas como homozigotas (HOM) ou heterozigotas (HET) para o microssatélite (STR) BMS3004, que está localizado no mesmo cromossomo do gene da cadeia do LH. Entre 60 e 80 dias pós-parto (dia 0), as vacas foram distribuídas em dois grupos. No grupo indução hormonal (IH), as vacas (n=87) receberam (dia 0) 250 mg de acetato de medroxiprogesterona por 8 dias, 2,5 mg de benzoato de estradiol (dia 1) e 500 UI de gonadotrofina coriônica eqüina (dia 7). No dia 8, os bezerros foram desmamados por 96 horas. No mesmo dia (dia 8), as vacas (n=96) do outro grupo apenas foram submetidas ao desmame definitivo (grupo DP). Após, procedeu-se 4 dias de inseminação artificial (IA) e, passado esse período, foram entouradas. O primeiro diagnóstico de gestação (DG) foi realizado 60 dias após o período de IA e, o segundo, 60 dias após o final do entoure. As taxas de estro foram maiores nas vacas do grupo IH em relação as do grupo DP. As vacas com condição corporal 2,5 e 3,0 apresentaram menores percentuais de prenhez ao 1ºDG no grupo IH (29,6 e 46,4%) em relação ao grupo DP (56,0 e 72,2%). Os percentuais de prenhez das vacas com índice corporal 65-73 não diferiram entre os grupos IH e DP. As vacas N do grupo IH, apresentaram menor percentual de prenhez ao 1ºDG que as F1 (27,7 vs. 64,2%), mas não diferiram em relação às C (40,0%). No grupo IH, o percentual de prenhez ao 2ºDG foi menor nas vacas HOM do que nas HET. O desmame definitivo precoce mostrou-se mais eficaz no incremento dos percentuais de prenhez em vacas de corte. ___________________________________________________________________________________ ABSTRACT The aim of this experiment was to compare the efficiency of a hormonal protocol, associated to the temporary weaning for 96 hours, with the definitive weaning at 60 days in beef cows, for the induction of estrus and ovulation. One hundred and eightythree suckled beef cows were used. The breeds of the cows were Charolais (C) and Nellore (N) and their crosses. The animals were genotyped as homozygous (HOM) and heterozigous (HET) for the microsatellite BMS3004, that is localized in the same chromossome of the LH chain gene. The cows were distributed in two groups between 60 and 80 days postpartum (day 0). In the hormonal induction group (HI), the cows (n=87) received (day 0) 250 mg of medroxiprogesteron acetate for 8 days, 2.5 mg of estradiol benzoate (day 1) and 500 UI of eCG (day 7). On day 8, the calves were weaned for 96 hours. In the same day (day 8), the cows (n=96) of the other group were just submitted to early weaning (group EW). Twelve hours after weaning, artificial insemination (AI) was done during four days. After this period, they were mated. The first diagnosis of pregnancy (DP) was performed 60 days after the AI period and, the second, 60 days after the end of mating. The estrus rates were higher in cows from HI group than in those of EW group. In the HI group, the cows with body condition 2.5 and 3.0 presented lower pregnancy rates at the 1st DP (29.6 and 46.4%) than in the EW group (56.0 and 72.2%). The rates of pregnancy in cows with body index 65-73 did not differ between the HI and EW groups. The N cows of HI group presented lower pregnancy rate at 1st DP than the F1 (27.7 vs. 64.2%), but was not different than the C cows (40.0%). In the HI group, the pregnancy rate at the 2nd DP was lower in HOM cows than in the HET ones. The cows in the early definitive weaning group showed to be more efficient than in the hormonal induction group to improve the pregnancy rate.

The present study evaluated whether the gonadotrophin surge modulates components of the renin–angiotensin system and whether angiotensin II (Ang II) plays a role in the production of hormones by follicular cells during the ovulatory process. In Experiment 1, cows were ovariectomised at various times (0, 3, 6, 12 and 24h) after GnRH injection to obtain preovulatory follicles. The concentration of Ang II in follicular fluid increased after GnRH and reached a peak at 24h, concomitant with the peak of angiotensinogen (AGT) mRNA expression in granulosa cells. AGT mRNA was not expressed in theca cells. Ang II receptor type 2 and angiotensin-converting enzyme mRNA levels were transiently upregulated in theca cells. In Experiment 2, an in vitro culture was used to determine whether Ang II could modulate hormone production by healthy dominant follicles. In the absence of LH, Ang II did not alter hormonal production by either theca or granulosa cells. Ang II plus LH increased progesterone and prostaglandin secretion by granulosa cells. In summary, the renin–angiotensin system is actively controlled during the preovulatory period and Ang II amplifies the stimulatory effects of LH on the secretion of progesterone and prostaglandins by granulosa cells.

The aim of our study was to evaluate the effect of different cooling rates on the post-thawing quality of bovine spermatozoa. Ejaculated semen from a 24-month-old Jersey bull was collected using an artificial vagina and diluted in a commercial extender to evaluate spermatozoan concentration and motility subjectively before cooling and freezing and after thawing. Straws were allocated to four cooling curves: rapid (RD), semi-rapid (SRD), semi-slow (SSLW) and slow (SLW). The temperature was decreased from 25ºC to 4ºC in 10, 50, 110 and 135 min, which represents a cooling rate of 2.06, 0.40, 0.18 and 0.15ºC/min, respectively. Then straws were frozen and stored at -196ºC. After thawing, one aliquot of each straw was used for evaluation. Spermatozoan integrity and mitochondrial function were evaluated using a combination of fluorescent probes containing 100 mg/mL FITC-PSA, 0.5 μg/mL PI and 153 μM JC-1. At the end of cooling, spermatozoan motility did not differ among RD (63.3%), SRD (66.7%), SSLW (66.7%) and SLW (80.0%). However, normal spermatozoan morphology was lower in SRD (84.8%) compared to RD (91.7%), SSLW (91.7%) and SLW (90.3%) (P

The objectives were to investigate the effects of pretreatment with a used CIDR on follicle size and ovulation rate in cows after an injection of GnRH, and treatment with eCG at the time of PGF on preovulatory follicle size and fertility in cows subjected to a Cosynch protocol. Lactating crossbred beef cows (n = 292), 2 to 12 years of age were allocated to two groups to receive either a used CIDR (Bioniche Animal Health; Belleville, Ontario, Canada) for 15 days or no treatment (Control). At CIDR removal (Day 0), all cows received 100 μg of GnRH i.m. (Cystorelin, Merial Canada Inc., Victoriaville, Quebec, Canada). On Day 7, all cows received 500 μg of cloprostenol i.m. (PGF; Estrumate, Schering-Plough Animal Health, Pointe-Claire, Quebec, Canada) and were further allocated to receive either 400 IU of eCG i.m. (Pregnacol; Bioniche Animal Health) or no treatment (2 × 2 factorial design; n = 73 per group). On Day 9 (54 h after PGF), cows were given 100 μg of GnRH i.m., concurrent with timed AI (TAI). Transrectal ultrasonographic examinations were done on a subset of approximately 40 cows in each group on Days −15, 0, 7, and 9 to assess ovarian structures, and on all cows on Day 37 to confirm pregnancy. Data were analyzed by SAS CATMOD and ANOVA. Overall, 53% of cows had a CL present on Day −15 (P = 0.23). At first GnRH (Day 0), fewer CIDR-treated cows than Control cows had a CL (15.2 vs. 85.0%, respectively; P < 0.001), while mean (± SEM) diameters of the dominant follicle were larger in CIDR-treated cows (18.2 ± 0.4 vs. 13.8 ± 0.4 mm, respectively; P < 0.001). Moreover, the proportion of cows that ovulated following the first GnRH was higher (P < 0.001) in CIDR-treated (75.0%) than Control (48.7%) cows. Eight (10.0%) cows presynchronized with a CIDR did not ovulate and had a luteinized follicle (31.7 ± 1.9 mm) at the time of PGF. Although CIDR-treated cows had larger (P < 0.002) dominant follicles than Control cows on Day 9 (16.6 ± 0.3 vs. 15.2 ± 0.3 mm), presynchronization did not affect fertility (53.4 vs. 54.1%, respectively). However, diameter of the dominant follicle at TAI in cows that became pregnant was smaller in CIDR-treated vs. Control cows (15.3 ± 0.3 vs. 16.6 ± 0.3; P < 0.005). Treatment with eCG on Day 7 did not affect (P = 0.17) the diameter of the dominant follicle at TAI, but tended (P = 0.06) to increase pregnancy rate (58.9 vs. 48.6%). Furthermore, pregnancy rate tended to be higher (P = 0.08) in Control cows given eCG (47/73, 64.4%) than in the Control- (32/73, 43.8%), CIDR- (39/73, 53.4%) or CIDR/eCG- (39/73, 53.4%) treated cows. In addition, pregnancy rate was affected by parity; 2-yr-old cows had a lower (P < 0.04) pregnancy rate than older cows (42.9, 58.7, and 58.2% for 2, 3–4, and >5 years, respectively). Treatment with eCG increased pregnancy rate by 33% (P < 0.03) in 2-yr-old Control cows. In summary, presynchronization with a used CIDR prior to a Cosynch protocol increased the proportion of cows responding to the first GnRH. Although CIDR-treated cows had a smaller dominant follicle at TAI, pregnancy rate was not affected. Treatment with eCG increased fertility in Control cows; eCG may be useful in GnRH-based protocols in lactating beef cows.

Two experiments were designed to evaluate strategies to improve fertility with Cosynch-CIDR protocols in cattle. The first experiment investigated the effect of low levels of progesterone prior to a Cosynch-CIDR protocol. On Day 0, lactating beef cows (n = 34) and heifers (n = 37) were placed in two groups to receive 500 μg cloprostenol (PGF; Estrumate, Schering-Plough Animal Health, Pointe-Claire, Quebec, Canada) or a twice-used CIDR (Bioniche Animal Health, Belleville, Ontario, Canada) for 5 days (Pretreatment) or no treatment (Control). On Day 5, used CIDRs were removed and all cattle received a new CIDR (Pfizer Animal Health, Montreal, Quebec, Canada) and 100 μg GnRH (Cystorelin, Merial Canada Inc, Victoriaville, Quebec, Canada). On Day 12, CIDR were removed and PGF was given. A second GnRH was given concurrent with timed AI (TAI) on Day 14 (54–56 h after PGF). Cattle were examined by transrectal ultrasonography for CL and follicle development, and for confirmation of pregnancy (Days 42 to 49). Diameter of the dominant follicle on Day 5 was larger and more variable in cows than in heifers (15.5 ± 5.6 vs. 11.4 ± 3.5 mm, respectively; means, P < 0.001; variance, P < 0.003), and tended to be larger in the Pretreatment group (14.3 ± 4.9 vs. 12.6 ± 5.2 mm; P = 0.13). More Pretreated (60.0%) than Control (36.1%) cattle (P < 0.005), and more cows (64.7%) than heifers (32.4%; P < 0.03) ovulated following the first GnRH. At the time of TAI, 5 (13.5%) heifers had already ovulated (P < 0.03). Diameter of the preovulatory follicle was affected by parity (P < 0.001), but not Pretreatment (P = 0.4), and tended to be larger in heifers that became pregnant (P = 0.13). Pregnancy rate was not affected by parity (P = 0.71), or pretreatment (P = 0.34); pretreatment tended to increase pregnancy rate in heifers (63.2 vs. 38.9%; P = 0.19). The second experiment evaluated the use of eCG in a Cosynch-CIDR protocol in beef heifers. Beef heifers (n = 127) were fed 0.5 mg/head/day of MGA (Pfizer Animal Health) for 15 d; 12 d after the last feeding (designated as Day 0) heifers received a CIDR and 100 μg GnRH. On Day 7, CIDR were removed, and heifers received PGF, and were randomly placed in 2 groups to receive 300 IU of eCG (Pregnacol; Bioniche Animal Health) or no treatment (Control). On Day 9 (54–56 h after PGF), all heifers received 100 μg GnRH, concurrent with TAI. Ultrasonographic examinations were done as in the first experiment. Overall, 79.5% of the heifers had a CL, and 9.4% had a luteinized follicle on Day 0. Seventy-eight heifers (61.4%) ovulated following the first GnRH, and those that ovulated had a less variable preovulatory follicle size than those that did not (13.7 ± 1.7 vs. 13.8 ± 2.3 mm; means, P = 0.76; variance, P < 0.01). However, there was no difference in preovulatory follicle size (P = 0.63), or pregnancy rate (49.2 vs. 53.1%; P = 0.7) for eCG-treated vs. Control heifers. In summary, pretreatment with a twice-used CIDR plus PGF increased the proportion of cattle that ovulated to the first GnRH, but not preovulatory follicle size or fertility in cows; fertility tended to be improved in heifers. Treatment with eCG did not increase preovulatory follicle size or fertility in heifers subjected to an Cosynch-CIDR protocol.