Desempenho reprodutivo de novilhas acasaladas aos 14 e 27 meses de idade submetidas a diferentes protocolos para a inseminação artificial / Reproductive performance of beef cattle heifers mated to 14 or 27 months of age subject to different protocols for artificial insemination

Avaliaram-se os efeitos de diferentes protocolos de inseminação sobre o desempenho reprodutivo em 249 novilhas Britânicas e cruzas, acasaladas aos 14 e 27 meses de idade. Sessenta e duas novilhas de 27 meses foram submetidas à IATF após o tratamento OvSynch; 61 novilhas de 27 meses e 32 novilhas de 14 meses foram submetidas à IATF após o tratamento Crestar; 62 novilhas de 27 meses e 32 novilhas de 14 meses foram submetidas à inseminação artificial (IA) após detecção de estros por 7 dias, no 7º dia foi aplicado PGF2a nos animais não observados em estro postergando-se IA por mais 5 dias (grupo PGF2a). Foram avaliados o peso vivo (PIA), o escore de condição corporal (ECC), o escore de trato reprodutivo (ETR) ao início da estação reprodutiva, a taxa de concepção e a taxa de prenhez à IATF, a taxa de prenhez ao término da estação. Os tratamentos OvSynch e Crestar tiveram 100% dos animais inseminados (IATF), enquanto os grupos PGF2a-14 meses e PGF2a-27 meses tiveram, respectivamente apenas 21,9% e 43,5% dos animais inseminados, devido à ausência ou falhas na identificação de cio. Não houve diferença nas taxas de concepção entre tratamentos hormonais e idades (P>0,05), com valores respectivos de 46,5%, 56,3%, 64,7% para os tratamentos Crestar, OvSynch, PGF2a e de 44,4% e 57,1%, para as idades 14 e 27 meses. A taxa de prenhez à IA (TF) foi de 46,5%, 56,3%, 23,4% para os tratamentos Crestar, OvSynch, PGF2a, com superioridade significativa (P<0,05) a favor dos grupos Crestar e OvSynch. A taxa de prenhez à IA (TF) foi de 18,6% e 41,3% (P<0,01) para as idades 14 e 27 meses. A taxa de prenhez final, após o repasse com touros foi respectivamente de 93,0%, 96,9%, 90,4% para os tratamentos Crestar, OvSynch, PGF2a e de 97,7% e 90,5%, para as idades 14 e 27 meses, sem diferença significativa. O ETR influenciou a taxa de prenhez após a inseminação, respectivamente de 0%, 25,6% e 48,8% para os ETR 1, 2 e 3. Os tratamentos hormonais para a IATF resultaram em maior taxa de prenhez...(AU)

The effects of three insemination protocols were evaluated on the reproductive performance in 249 British and crosses beef heifers, mated to the 14 or 27 months of age. Sixty two heifers with 27 months were submitted to FTAI after the treatment OvSynch; 61 heifers with 27 months and 32 heifers with 14 months were submitted to FTAI after the treatment to Crestar; 62 heifers with 27 months and 32 heifers with 14 months were submitted to the artificial insemination (AI) after oestrus detection for 7 days, in the 7th day PGF2a was applied in the animals without oestrus observed being postponed AI during more 5 days (PGF2a group). The live weight and body condition score (BCS), the reproductive tract score (RTS) to the beginning of mating season, the conception and the pregnancy to FTAI and the pregnancy to the end of the mating season were evaluated. The treatments OvSynch and Crestar had 100% of the inseminated animals (FTAI), while the groups PGF2a-14 months and PGF2a-27 months had respectively, only 21.9% and 43.5% of the inseminated animals, due to the absence or fails in the oestrus identification. There was no difference in the conception rates between hormonal treatments and ages (P>0.05), with respective values of 46.5%, 56.3%, 64.7% for the treatments Crestar, OvSynch, PGF2a and of 44.4% and 57.1%, for the ages 14 and 27 months. The pregnancy rate to FTAI/AI it was of 46.5%, 56.3%, 23.4% for the treatments to Crestar, OvSynch, PGF2a, with significant superiority (P<0.05) in favor of the groups Crestar and OvSynch. The pregnancy rate to AI (FTAI) it was of 18.6% and 41.3% (P <0,01) for the ages 14 and 27 months. The final pregnancy rate, after clean-up bulls was respectively of 93.0%, 96.9%, 90.4% for the treatments to Crestar, OvSynch, PGF2a and of 97.7% and 90.5%, for the ages 14 and 27 months, without significant difference. RTS influenced the pregnancy rate after the insemination, respectively of 0%, 25,6% and 48,8% for RTS 1, 2 and 3. The hormonal...(AU)

Desempenho reprodutivo de novilhas acasaladas aos 14 e 27 meses de idade submetidas a diferentes protocolos para a inseminação artificial / Reproductive performance of beef cattle heifers mated to 14 or 27 months of age subject to different protocols for artificial insemination

Avaliaram-se os efeitos de diferentes protocolos de inseminação sobre o desempenho reprodutivo em 249 novilhas Britânicas e cruzas, acasaladas aos 14 e 27 meses de idade. Sessenta e duas novilhas de 27 meses foram submetidas à IATF após o tratamento OvSynch; 61 novilhas de 27 meses e 32 novilhas de 14 meses foram submetidas à IATF após o tratamento Crestar; 62 novilhas de 27 meses e 32 novilhas de 14 meses foram submetidas à inseminação artificial (IA) após detecção de estros por 7 dias, no 7º dia foi aplicado PGF2a nos animais não observados em estro postergando-se IA por mais 5 dias (grupo PGF2a). Foram avaliados o peso vivo (PIA), o escore de condição corporal (ECC), o escore de trato reprodutivo (ETR) ao início da estação reprodutiva, a taxa de concepção e a taxa de prenhez à IATF, a taxa de prenhez ao término da estação. Os tratamentos OvSynch e Crestar tiveram 100% dos animais inseminados (IATF), enquanto os grupos PGF2a-14 meses e PGF2a-27 meses tiveram, respectivamente apenas 21,9% e 43,5% dos animais inseminados, devido à ausência ou falhas na identificação de cio. Não houve diferença nas taxas de concepção entre tratamentos hormonais e idades (P>0,05), com valores respectivos de 46,5%, 56,3%, 64,7% para os tratamentos Crestar, OvSynch, PGF2a e de 44,4% e 57,1%, para as idades 14 e 27 meses. A taxa de prenhez à IA (TF) foi de 46,5%, 56,3%, 23,4% para os tratamentos Crestar, OvSynch, PGF2a, com superioridade significativa (P<0,05) a favor dos grupos Crestar e OvSynch. A taxa de prenhez à IA (TF) foi de 18,6% e 41,3% (P<0,01) para as idades 14 e 27 meses. A taxa de prenhez final, após o repasse com touros foi respectivamente de 93,0%, 96,9%, 90,4% para os tratamentos Crestar, OvSynch, PGF2a e de 97,7% e 90,5%, para as idades 14 e 27 meses, sem diferença significativa. O ETR influenciou a taxa de prenhez após a inseminação, respectivamente de 0%, 25,6% e 48,8% para os ETR 1, 2 e 3. Os tratamentos hormonais para a IATF resultaram em maior taxa de prenhez...

The effects of three insemination protocols were evaluated on the reproductive performance in 249 British and crosses beef heifers, mated to the 14 or 27 months of age. Sixty two heifers with 27 months were submitted to FTAI after the treatment OvSynch; 61 heifers with 27 months and 32 heifers with 14 months were submitted to FTAI after the treatment to Crestar; 62 heifers with 27 months and 32 heifers with 14 months were submitted to the artificial insemination (AI) after oestrus detection for 7 days, in the 7th day PGF2a was applied in the animals without oestrus observed being postponed AI during more 5 days (PGF2a group). The live weight and body condition score (BCS), the reproductive tract score (RTS) to the beginning of mating season, the conception and the pregnancy to FTAI and the pregnancy to the end of the mating season were evaluated. The treatments OvSynch and Crestar had 100% of the inseminated animals (FTAI), while the groups PGF2a-14 months and PGF2a-27 months had respectively, only 21.9% and 43.5% of the inseminated animals, due to the absence or fails in the oestrus identification. There was no difference in the conception rates between hormonal treatments and ages (P>0.05), with respective values of 46.5%, 56.3%, 64.7% for the treatments Crestar, OvSynch, PGF2a and of 44.4% and 57.1%, for the ages 14 and 27 months. The pregnancy rate to FTAI/AI it was of 46.5%, 56.3%, 23.4% for the treatments to Crestar, OvSynch, PGF2a, with significant superiority (P<0.05) in favor of the groups Crestar and OvSynch. The pregnancy rate to AI (FTAI) it was of 18.6% and 41.3% (P <0,01) for the ages 14 and 27 months. The final pregnancy rate, after clean-up bulls was respectively of 93.0%, 96.9%, 90.4% for the treatments to Crestar, OvSynch, PGF2a and of 97.7% and 90.5%, for the ages 14 and 27 months, without significant difference. RTS influenced the pregnancy rate after the insemination, respectively of 0%, 25,6% and 48,8% for RTS 1, 2 and 3. The hormonal...

Effect of intramuscular injection of butafosfan and cobalamin on the quality of fresh and cooled stallion semen / Efeito da administração intramuscular de butafosfan e cobalamina na qualidade do sêmen fresco e resfriado de garanhões

The use of butafosfan in combination with cobalamin modulates many cellular metabolic functions in several species. Its use enhances productive and reproductive performance and reduces stress responses in animals. Despite all these attributes, so far there have been no controlled studies to evaluate the effects of butafosfan and cobalamin on the quality of stallion semen. The purpose of this study was to evaluate the action of butafosfan in combination with cobalamin on the quality of fresh and cooled stallion semen. Four healthy stallions were kept in the same place and under the same management conditions during the entire experiment. Stallions were randomly assigned to two treatment groups in a 2x2 crossover design. Group A stallions were treated with an intramuscular injection of butafosfan twice a week for 80 days, while group B did not receive any treatment. After that, both groups were not treated for another 80 days allowing a washout period for the treated group. Then, the groups were reversed, and group B was treated with butafosfan and group A acted as the control for another 80 days. Semen was collected twice a week, diluted in skim milk and evaluated for total sperm count, total and progressive sperm motility, membrane integrity (CFDA/PI staining) and membrane functionality (HOS test) at 0 and 24 hours after preservation at 5ºC. Data were analyzed by comparing the...(AU)

A utilização de Butafosfan em combinação com cobalamina modula uma série de funções metabólicas celulares em várias espécies. Seu uso melhora o desempenho produtivo e reprodutivo e reduz as respostas ao estresse em animais. Apesar de todos esses atributos, até agora não houve estudos controlados para avaliar os efeitos da substância Butafosfan e cobalamina sobre a qualidade do sêmen de garanhões. O objetivo deste estudo foi avaliar a ação do Butafosfan em combinação com cobalamina sobre a qualidade do sêmen fresco e resfriado de garanhões. Quatro garanhões saudáveis foram mantidos no mesmo lugar e sob as mesmas condições de manejo durante todo o experimento. Garanhões foram divididos aleatoriamente em dois grupos de tratamento em um desenho cruzado 2x2. Garanhões do grupo A foram tratados com uma injeção intramuscular de Butafosfan duas vezes por semana durante 80 dias, enquanto o grupo B não recebeu qualquer tratamento. Depois disso, ambos os grupos não foram tratados durante mais 80 dias, permitindo um período de washout para o grupo tratado. Em seguida, os grupos foram invertidos, o grupo B foi tratado com Butafosfan enquanto o grupo A agiu como controle por mais 80 dias. O sêmen foi coletado duas vezes por semana, diluído em leite desnatado e avaliado para a contagem total de espermatozoides, motilidade progressiva e total, integridade da membrana (coloração CFDA/PI) e...(AU)

Resposta reprodutiva de novilhas de corte associada a marcadores moleculares relacionados à fertilidade / Reproductive Performance of Beef Cattle Heifers Associated with Molecular Markers Related to the Fertility

Background: The marker assisted selection (MAS) is indicated as an auxiliary strategy to increase the productive performance in cattle. The principle consists in the identifi cation and selection of molecular markers associated with genes involved directly or indirectly with the expression of a desired trait, usually multifactorial and polygenic. The pregnancy rate is a form of expression fertility, with great economic importance in cattle production systems. The pregnancy rate is a multifactorial trait, which is infl uence by genetics, environment and their interactions. In the current study was search for an association between the reproductive response, expressed by pregnancy rate at insemination and pregnancy rate at the end of the mating season, and molecular markers of genes related to IGF-1 receptor, LHß, Leptin, receptors of FSH and LH. Materials, Methods & Results: Data were evaluated from 249 beef heifers of British breeds, Angus, Devon and crosses. The animals at fourteen or twenty seven months were subjected to different protocols for artificial insemination (AI) and fixed-time artificial insemination (TAI), followed by clean up bulls. The protocols AI and TAI, called AI/TAI, were: Group 1 -Ovsynch protocol (27th months). At day zero the animals received an injection of a GnRH at a dose of 10 µg buserelin, at seventh day received 500 µg of cloprostenol sodium, at ninth day the animals received another dose of 10 µg of buserelin. TAI was performed 10 h after the application of buserelin; Group 2 - Protocol Crestar® with ½ dose of estradiol valerate injectable (27th months). At eighth day the implant was removed, followed by 375 µg of cloprostenol sodium. At ninth day, was administered 1 mg of estradiol benzoate. TAI was performed in tenth day, 52 h after implant removal; Group 3 - Control group (27th months), with AI 12 h after estrus during the fi rst seven days. Seventh day, was applied 375 µg of cloprostenol sodium on all heifers not inseminated, followed by AI for fi ve days more; Group 4 (14th months) - Same protocol of the Group 2; Group 5 (14th months) - Same protocol of the Group 3. During the group formation, blood samples for extraction of DNA were obtained individually from all experimental animals. Microsatellite markers (short tandem repeats, STR) and/or single nucleotide polymorphisms (SNPs) were investigated by means of polymerase chain reaction (PCR). The STR investigated were the AFZ-1, HEL5, ILST002, IDVGA51, FSHR and LHR. We considered the effects of the treatment groups, age, body condition score (BCS), reproductive tract score (RTS), weight at the beginning of the breeding season, daily weight gain on pregnancy rate to AI/TAI and pregnancy rate to final. Molecular markers investigated did not show association with pregnancy rate. The mean pregnancy rate at insemination was 41.0% and the pregnancy rate final was 91.6%. There were no differences in pregnancy between the age of the animals. The average weight at the beginning of the mating was 313 kg without differentiate between animal that become pregnant or empty during the reproductive season. The RTS influenced the pregnancy rate after insemination in respectively 0%, 32.1% and 49.5% (P < 0.05) for RTS 1, 2 and 3. Discussion: Molecular markers AFZ-1, HEL5, ILST002, IDVGA51, FSHR and LHR could not be associated with pregnancy rate at insemination and pregnancy in beef heifers, perhaps because the high degree of reproductive selection that these animals are subjected. The nutritional status of the herd, expressed by weight and body condition score at mating of animals contributed to the achievement of significant pregnancy rates. The reproductive tract score can be considered as a predictor of fertility in herds of beef heifers.

Avaliação do desempenho reprodutivo de vacas de corte lactantes submetidas à IATF a partir da aplicação do GnRH, da manifestação estral, da reutilização de dispositivos intravaginais e da condição corporal / Evaluation of reproductive performance of lactating beef cows subjected to FTAI from the application of Gnrh, estrus manifestation, re-use of intravaginal devices and body condition

Background: The success of fixed-time artificial insemination (FTAI) is linked to several factors that affect pregnancy rates. The use of different hormones, estrus expression and body condition score (BCS) are variables that can influence the results of the technique. The increased production of calves provides greater amount of steers to slaughter. The productive intensification of the beef cows breeding depends on factors related to reproductive technique used and the physiological conditioning of animals. The objective of this study was to evaluate the effect of the application of GnRH, estrus manifestation, re-use of progesterone intravaginal devices and BCS on pregnancy rates of cows subjected to FTAI. Materials, Methods & Results: Were analyzed the effects of GnRH injection and re-use of intravaginal device, estrus manifestation and body condition score (BCS) on reproductive performance of 222 Montana beef cows subjected to fixedtime artificial insemination (FTAI). The FTAI protocol was based on the placement of intravaginal progesterone device (1st, 2nd or 3rd use) and application of estradiol benzoate (E.B.) (2 mg) on day 0. On day 8 was applied sodium cloprostenol (500 µg), removed the intravaginal device and performed the separation of calves. On day 9 was applied E.B. (1 mg) and started the observation of estrus in the morning, afternoon and morning of day 10. On the afternoon of day 10 was realized the insemination, part of the animals showed estrus received buserelin acetate (GnRH) (100µg); the same was proceeded with the animals without estrus. After FTAI the calves returned to cows. Thus, it was formed four groups: Without-Estrus/Without-GnRH; Without-Estrus/With-GnRH; With-Estrus/Without-GnRH; With-Estrus/With-GnRH. The evaluation alone of application of GnRH (with and without) and estrus manifestation (with and without) had no effect on pregnancy rates to FTAI and pregnancy final (P > 0.05). The evaluation of the interaction between GnRH and estrus had no effect on the FTAI pregnancy (P > 0.05): cows Without-Estrus/Without-GnRH did not differ those with GnRH, 33.3% and 48.4% respectively; cows With-Estrus/Without-GnRH did not differ those with GnRH, 53.2% and 53.8% respectively. Intravaginal device 1st, 2nd and 3rd use did not influence pregnancy rates to FTAI and final pregnancy, 50.0%, 57.7%, 41.7% and 91.7%, 88.5%, 93 8% respectively (P > 0.05). The BCS influenced the pregnancy rate to FTAI and final pregnancy, animals with BCS ≥ 3.0 had a higher pregnancy rate to FTAI and animals with BCS ≥ 2.5 had a higher pregnancy to final pregnancy (P < 0.05). The BCS also influenced the estrus manifestation, animals with BCS ≥ 2.5 had higher rates of estrus (P < 0.05). The intravaginal device 1st use promoted greater estrus manifestation in relation to the 2nd and 3rd use (P < 0.05). Discussion: The pregnancy rates did not have the effect of application of GnRH. Some studies report that effect of GnRH is related to estrus phase of the cow. Although 11 percentage points above to cows with estrus, the manifestation estrus did not influence the pregnancy and also did not interact with GnRH. However, it is reported that estrus before at insemination may be conducive to conception. The intravaginal devices used did not influence the pregnancy rates, showing that it is possible re-use them. The results showed at importance of BCS to pregnancy, studies report that cows with low BCS have difficulty to pregnant at FTAI and clean-up bulls. The estrus manifestation was influenced by the BCS and the intravaginal device used.

Suplementação de touros com sabões cálcicos de ácidos graxos poli-insaturados e qualidade seminal pré e pós-congelação / Bulls supplemented with calcium soaps of polyunsaturated fatty acids and semen quality before and after freezing

O objetivo deste experimento foi avaliar a qualidade seminal de touros suplementados com sabões cálcicos de ácidos graxos poli-insaturados (PUFA). Vinte touros das raças Angus, Brangus, Hereford e Braford foram distribuídos aleatoriamente em dois grupos, cada um com dez animais. Cada grupo recebeu uma dieta composta de volumoso, ração comercial, sal mineral e um de dois suplementos: funcional com a incorporação de sabões cálcicos de PUFA ou energético, com a incorporação de raspa de mandioca (Manihot esculenta, Crantz). Durante o período experimental, a qualidade seminal foi avaliada utilizando testes rotineiros (volume, concentração, motilidade em massa, motilidade individual e avaliação da morfologia espermática) e testes complementares (teste hiposmótico, coloração dupla giemsa/tripan-azul e teste de termorresistência). O sêmen in natura do grupo de touros suplementados com sabões cálcicos de PUFA comercial (Megalac-E®) apresentou aumento na motilidade espermática (83,3% vs. 75,3%), na percentagem de espermatozoides com acrossoma íntegro (94,8% vs. 91,8%) e na percentagem de espermatozoides viáveis (98,0% vs. 96,6%) quando comparado com o sêmen do grupo de touros suplementados com raspa de mandioca (P<0,05). O tipo de suplemento não afetou o volume seminal, a concentração espermática e concentração de testosterona em sangue (P>0,05). Foram encontradas interações entre tratamento e número de coleta para percentagem de espermatozoides morfologicamente normais e percentagem de espermatozoides positivos ao teste hipo-osmótico (P<0,05). Após a descongelação, o tipo de suplemento não afetou a motilidade dos espermatozoides, o teste hipo-osmótico e o teste de termoresistência rápido (P>0,05). A suplementação com sabões cálcicos de PUFA aumentou as percentagens de espermatozoides com acrossoma íntegro (48,0% vs. 39,2%) e de espermatozoides com membrana plasmática integra (51,5% v.s 42,2%) pós-descongelação.(AU)

The objective of this experiment was to evaluate semen quality of bulls supplemented with calcium soaps of fatty acids polyunsaturated. Twenty Angus, Brangus, Hereford and Braford bulls were randomly allocated into two groups, each with ten animals. Each group received a diet consisting of forage, commercial ration, mineral supplements and supplement. Two supplements types were evaluated: functional supplement, with fatty acids polyunsaturated (PUFA) incorporation or energy supplement, with cassava meal (Manihot esculenta, Crantz) incorporation. During trial period the semen quality was evaluated using routine test (volume, concentration, mass motility, individual motility, sperm morphology) and complementary test: (hypo-osmotic test, giemsa/tripan-azul coloration and thermotolerance test). The semen of group bulls supplemented with commercial calcium soaps of PUFA (Megalac-E®) showed greater sperm motility (83.3% vs. 75.3%), percentage of sperm with intact acrosome (94.8% vs. 91.8%) and percentage of sperm with intact plasma membrane (98.0% vs. 96.6%) when compared with semen of group bulls supplemented with cassava (P<0.05). The supplement type did not affect semen volume, sperm concentration and testosterone concentration in blood (P>0.05). There were interactions between treatment and collection period for percentage of normal sperm and percentage of spermatozoa with hypo-osmotic positive test (P<0.05). The type of supplement did not affect sperm motility, the hypo-osmotic test and fast thermotolerance test after thawing (P>0.05). PUFA calcium soaps supplementation increased percentage of spermatozoa with plasma membrane integrity (51.5 vs. 42.2%) and spermatozoa intact acrosome (48.0% vs. 39.2%) after thawing.(AU)

Níveis séricos de progesterona em vacas ovariectomizadas tratadas com Mad4® com diferentes concentrações e vias de administração / Serum progesterone levels in ovariectomised cows treated with mad-4® with different concentrations and routes of administration

Background: Progesterone and synthetic progestogens are used to prepare the uterus for pregnancy, and for the hypothalamus, pituitary and ovaries to respond to endogenous and exogenous gonadotropins. The object of this work was to check serum progesterone concentrations in ovariectomised cows, to determine pharmacokinetics of MAD-4 ® product. Materials, Methods & Results: A group of eigth Braford cows was divided into two groups, in two experiments. In experiment I, both groups received 250 mg of progesterone by different routes of application: intramuscular or subcutaneous. In experiment II, subcutaneous application was used in both groups, the differentiation of the treatments lying in the concentration of progesterone: treatment 2 received 250 mg progesterone and treatment 3 was administered 375 mg of progesterone. In the first 24 h samples were collected in intervals of 6 hours, then every 24 h up to 192 h (day 8). In experiment I there was a significant difference (P < 0.05) at 96 h, showing greater concentration in treatment 2 compared to treatment 1 (1.54 ng/mL vs. 0.48 ng/ mL, respectively). In experiment II, in the measures undertaken at 144 h, 168 h and 192 h with significant difference (P < 0.05), concentrations of progesterone in treatment 2 were lower when compared to treatment 3 (0.79 ng/mL vs. 1.63 ng/mL, 0.66 ng/ mL vs. 1.36 ng/mL and 0.49 ng/mL vs. 1.11 ng/mL respectively for hours and treatments). Due to the fact that the types of progestogens and doses used to control the estrous cycle in cattle may be less effective than endogenous progesterone (a corpus luteum) with respect to suppression of LH, the high frequency of LH pulses results in development of “persistent” follicles containing aged eggs of low fertility. In this study, the application of 250 mg of intramuscular and subcutaneous long action injectable progesterone elevated progesterone serum concentration above 1 ng/mL. Subcutaneous application presented levels exceeding 1 ng/mL for a longer time, from 6 to 96 h. This treatment probably suppresses LH pulses temporarily without staying very long in the bloodstream; for this reason it doesn’t impair fertility. The same cannot be said in the treatment situation with the application of 375 mg subcutaneous long-action injectable progesterone, because, as long as progesterone was measured (day 8), the concentration remained higher than 1 ng/mL. Discussion: Vaginal silicone implants impregnated with 0.5 g of progesterone, when used for the second time (7 days each time), failed to maintain serum progesterone levels for more than 24 h higher than 1 ng/mL. In this study, treatment with 250 mg intramuscular long-action injectable progesterone showed similar serum concentrations over time, because between 24 and 48 h the levels were below 1 ng/mL. Parenteral routes of administration include, among others, the intramuscular (IM) and subcutaneous (SC). The intramuscular route is characterised by a relatively rapid absorption via the subcutaneous, is characterized by a slower absorption and continuous. Treatment of ovariectomised cows with long-acting injectable progesterone in different doses and by different routes resulted in significantly different serum concentrations at some moments, characteristic of each route of administration and doses used. In this study we can conclude that the seemingly more appropriate treatment is that which makes use of 250 mg of long-acting progesterone, subcutaneously injected, keeping progesterone serum levels higher than 1ng/mL per period of four days.

Níveis séricos de progesterona em vacas ovariectomizadas tratadas com Mad4® com diferentes concentrações e vias de administração / Serum progesterone levels in ovariectomised cows treated with mad-4® with different concentrations and routes of administration

Background: Progesterone and synthetic progestogens are used to prepare the uterus for pregnancy, and for the hypothalamus, pituitary and ovaries to respond to endogenous and exogenous gonadotropins. The object of this work was to check serum progesterone concentrations in ovariectomised cows, to determine pharmacokinetics of MAD-4 ® product. Materials, Methods & Results: A group of eigth Braford cows was divided into two groups, in two experiments. In experiment I, both groups received 250 mg of progesterone by different routes of application: intramuscular or subcutaneous. In experiment II, subcutaneous application was used in both groups, the differentiation of the treatments lying in the concentration of progesterone: treatment 2 received 250 mg progesterone and treatment 3 was administered 375 mg of progesterone. In the first 24 h samples were collected in intervals of 6 hours, then every 24 h up to 192 h (day 8). In experiment I there was a significant difference (P < 0.05) at 96 h, showing greater concentration in treatment 2 compared to treatment 1 (1.54 ng/mL vs. 0.48 ng/ mL, respectively). In experiment II, in the measures undertaken at 144 h, 168 h and 192 h with significant difference (P < 0.05), concentrations of progesterone in treatment 2 were lower when compared to treatment 3 (0.79 ng/mL vs. 1.63 ng/mL, 0.66 ng/ mL vs. 1.36 ng/mL and 0.49 ng/mL vs. 1.11 ng/mL respectively for hours and treatments). Due to the fact that the types of progestogens and doses used to control the estrous cycle in cattle may be less effective than endogenous progesterone (a corpus luteum) with respect to suppression of LH, the high frequency of LH pulses results in development of “persistent” follicles containing aged eggs of low fertility. In this study, the application of 250 mg of intramuscular and subcutaneous long action injectable progesterone elevated progesterone serum concentration above 1 ng/mL. Subcutaneous application presented levels exceeding 1 ng/mL for a longer time, from 6 to 96 h. This treatment probably suppresses LH pulses temporarily without staying very long in the bloodstream; for this reason it doesnt impair fertility. The same cannot be said in the treatment situation with the application of 375 mg subcutaneous long-action injectable progesterone, because, as long as progesterone was measured (day 8), the concentration remained higher than 1 ng/mL. Discussion: Vaginal silicone implants impregnated with 0.5 g of progesterone, when used for the second time (7 days each time), failed to maintain serum progesterone levels for more than 24 h higher than 1 ng/mL. In this study, treatment with 250 mg intramuscular long-action injectable progesterone showed similar serum concentrations over time, because between 24 and 48 h the levels were below 1 ng/mL. Parenteral routes of administration include, among others, the intramuscular (IM) and subcutaneous (SC). The intramuscular route is characterised by a relatively rapid absorption via the subcutaneous, is characterized by a slower absorption and continuous. Treatment of ovariectomised cows with long-acting injectable progesterone in different doses and by different routes resulted in significantly different serum concentrations at some moments, characteristic of each route of administration and doses used. In this study we can conclude that the seemingly more appropriate treatment is that which makes use of 250 mg of long-acting progesterone, subcutaneously injected, keeping progesterone serum levels higher than 1ng/mL per period of four days.(AU)

Luteólise antecipada em protocolo de inseminação artificial em tempo fixo com progesterona em vacas no pós-parto / Early luteolisys in timed artificial insemination protocol with progesterone in post partum cows

Foi avaliado o efeito da aplicação de um luteolítico em dois momentos distintos sobre a taxa de concepção na inseminação artificial em tempo fixo (IATF) de vacas com cria ao pé, além de verificar a eficácia de implantes com 1 grama de P4 de primeiro e segundo uso. Foram utilizadas 210 vacas de corte lactantes da raça Montana divididas em dois lotes de 105 vacas, comparando oito grupos distribuídos nos lotes. O lote D6,5 foi tratado no dia zero com 2mg de benzoato de estradiol i.m. (BE, Estrogin®) juntamente com implante intravaginal de progesterona de 1º uso (G1- Sincrogest®, n=29; G2- Primer®, n=26) e de 2º uso (G3- Sincrogest®, n=26; G4- Primer®, n=24), no dia 6,5 foi aplicado 150mcg i.m. de Cloprostenol Sódico (Sincrocio®), sendo a retirada do implante de P4 no dia 8. Dia 9, ocorreu a aplicação de 1mg de BE i.m. e no dia 10 a tarde a IATF. O lote D8 iniciou o protocolo de IATF e foi tratado da mesma forma, à exceção da aplicação do luteolítico que ocorreu no oitavo dia. Os grupos foram formados: implante de 1º uso (G5- Sincrogest®, n=27; G6- Primer®, n=28) e de 2º uso (G7-Sincrogest®, n=26; G8- Primer®, n=24). As taxas de prenhez dos grupos do lote D6,5 foram de 55,17%(G1), 69,23%(G2), 57,67%(G3), 70,83% (G4) (p=0,263). No lote D8 os grupos G5, G6, G7, G8 deste lote apresentaram 44,44%, 67,86%, 46,15%, e 58,33% de prenhez (p=0,573). As taxas de prenhez para os lotes D6,5 e D8 foram, de 62,86% e 54,29%. Não houve diferença nas taxas de concepção a IATF entre os lotes (p= 0,262). Os implantes de primeiro e segundo uso Sincrogest® e Primer® foram efetivos para obter-se uma taxa de concepção em torno de 50% em vacas de corte lactantes. A antecipação da aplicação do Cloprostenol Sódico (D6,5) não foi efetiva para aumentar as taxas de concepção a IATF e prenhez ao final da estação de monta. A idade, condição corporal e os dias pós-parto não influenciaram na taxa de concepção a IATF e taxa de prenhez ao final da estação de monta.(AU)

The effect of luteolytic application was evaluated in two distinct moments about the range of pregnancy in the artificial insemination in fixed time of post partum cows, besides checking the efficacy of implants with 1 gram of progesterone of first and second use. 210 post partum cows of Montana breed were used divided into two different lots of 105 cows, comparing 8 groups. The lot D6,5 was treated on the day zero with 2mg of estradiol benzoate i.m. (BE, Estrogin®) together with the intravaginal implant of progesterone of first use (G1- Sincrogest®, n=29; G2- Primer®, n=26) and of second use (G3- Sincrogest®, n=26; G4- Primer®, n=24), on the day 6,5 150mcg i.m of Cloprostenol (Sincrocio®), the removal of the implant of P4 on the day 8. On the day 9, there was an application 1mg of BE i.m and on the day 10 in the afternoon the TAI. The lot D8 was treated on the same way, except for the application of luteolytic, that occurred on the eighth day. The groups were formed this way: first use (G5- Sincrogest®, n=27; G6- Primer®, n=28) and second use (G7-Sincrogest®, n=26; G8- Primer®, n=24). The ranges of pregnancy of the groups in the lot D6,5 were 55,17%(G1), 69,23%(G2), 57,67%(G3), 70,83%(G4) (p=0,263). In the lot D8 the groups G1, G2, G3, G4 of this lot presented 44,44%, 67,86%, 46,15%, e 58,33% of pregnancy (p=0,573). The ranges of pregnancy for the lots D6,5 and D8 were 62,86% e 54,29%. There was no difference in the ranges of pregnancy TAI between the lots (p= 0,262). The implants of first and second use Sincrogest ® and Primer ® were effective to obtain a pregnancy rate around 50% in lactating beef cows. The anticipation of applying Cloprostenol Sodic (D6, 5) was not effective to increase the conception rate to TAI and pregnancy rate at the end of the breeding season. The age, body condition and days postpartum did not influence the conception rate to TAI and pregnancy rate at the end of the breeding season.(AU)

Efeitos do uso de GNRH no momento da IATF e dias pós-parto sobre a taxa de prenhez em vacas de corte com cria ao pé / Effects of the use of GnRH in the moment of fixed-time artificial insemination and postpartum days on the pregnancy of the nursing beef cows

A falha na detecção de estros e o anestro pós-parto são as principais causas da baixa fertilidade nos rebanhos bovinos. Para minimizar estes problemas uma das biotecnologias recomendadas é o emprego da Inseminação Artificial em Tempo Fixo (IATF). O trabalho avaliou o uso de GnRH no momento da IATF e o número de Dias Pós-Parto (DPP) sobre o desempenho reprodutivo. Foram utilizadas 32 vacas de corte com cria ao pé, 15 vacas formaram o grupo GnRH e 17 o grupo controle. As vacas estavam com data média de 74 DPP por ocasião da IATF.Os animais formavam um grupo homogêneo sendo manejados em iguais condições.As vacas receberam no dia “0” 2 mg de benzoato de estradiol e implante intravaginal de progesterona usado previamente (2º uso), no 6º dia foi aplicado 0,375 mg de Cloprostenol Sódico e no 8º dia, pela manhã, foram retirados os implantes, separados os bezerros e foi aplicado 0,5 mg de cipionato de estradiol. No dia 10º dia pela tarde procedeu-se a IATF. Neste momento, aleatoriamente, de cada duas vacas uma recebia 100μg de análogo sintético ao GnRH. Sete dias após a IATF os animais

The lack of estrous detection and the postpartum anestrous are the largest causes of the low fertility in the beef cattle herds. To minimize these problems one of the recommended biotechnology it is the use of the fixed-time artificial insemination (TAI). This work evaluated the use of GnRH at the moment of TAI and the postpartum days (PPD) on the reproductive performance. Data of the thirty two cows rearing calves were used. Fifty cows formed the group GnRH and 17 the group control. The PPD of the cows were in medium 74 days for occasion of TAI. The animals formed one homogeneous group being handled equally. All cows received in the day “0” 2 mg of estradiol benzoato and one intravaginal implant content progesterone of 2nd use. On the 6th day was applied 0,375 mg of sodic cloprostenol and in the 8th day, by the morning, the implants were take off and the calves were separated temporarily and were applied 0,5 mg of estradiol cipionate. On the 10th day at the afternoon TAI was done. At this time randomly, one of each two cows received 100 µg of synthetic analogue to GnRH. Seven days after TAI the animals were allocated into one field with more 35 cows and 2 clean-up bulls during 60 days. It was evaluated the effects on the GnRH application on the Pregnancy rate at TAI (PRTAI) and the pregnancy rate after clean-up bulls (PRB). The effects of the PPD were analyzed on the PRTAI and PRB. The PRTAI was of 46.7% and 35.3%, respectively for the cows of the groups GnRH and control (P>0.05). The PRB was of 53.3% and 64.7%, respectively for the cows of the group GnRH and control (P>0.05). There was not relationship by the use of GnRH with PRTAI and PRB. For analyze the PPD it was formed two groups. One group (14 cows) with average of 57 ± 18.4 PPD (PPD57) and other group (18 cows) with average of 88 ± 9.1 PPD (PPD88). In the groups PPD57 and PPD88 the PRTAI was respectively 42.9% and 38.9% (P>0.05); and the PRB was respectively 64.3% and 55.6% (P>0,05)

Dinâmica folicular de vacas de corte tratadas com três protocolos de sincronização da ovulação / Ovarian Follicular Dynamics in Beef Cows Treated with Three Protocols of Synchronization of Ovulation

Artificial insemination is an established and viable technique to accelerate the genetic advancement and economic return of the cattle. However, compromises the efficiency of detection of estrus results in low insemination rates. To avoid these problems in beef herd, synchronization protocols have been developed that allow inseminate large number of animals within a set period of time. These treatments are known as protocols for synchronization of ovulation for fixed-time artificial insemination (FTAI). There are several slow-release progesterone or progestins devices on the market for use in synchronization of estrus/ovulation programs in cattle, but these devices have a high cost, which results in less use of these protocols by farmers . This study aimed to determine the follicular dynamic of a low cost protocol to synchronize ovulation, which uses vaginal sponges impregnated with medroxy-progesterone acetate (MPA; group 1) and compare it with two trade protocols (groups 2 and 3).

Efeitos do uso de GNRH no momento da IATF e dias pós-parto sobre a taxa de prenhez em vacas de corte com cria ao pé / Effects of the use of GnRH in the moment of fixed-time artificial insemination and postpartum days on the pregnancy of the nursing beef cows

A falha na detecção de estros e o anestro pós-parto são as principais causas da baixa fertilidade nos rebanhos bovinos. Para minimizar estes problemas uma das biotecnologias recomendadas é o emprego da Inseminação Artificial em Tempo Fixo (IATF). O trabalho avaliou o uso de GnRH no momento da IATF e o número de Dias Pós-Parto (DPP) sobre o desempenho reprodutivo. Foram utilizadas 32 vacas de corte com cria ao pé, 15 vacas formaram o grupo GnRH e 17 o grupo controle. As vacas estavam com data média de 74 DPP por ocasião da IATF.Os animais formavam um grupo homogêneo sendo manejados em iguais condições.As vacas receberam no dia “0” 2 mg de benzoato de estradiol e implante intravaginal de progesterona usado previamente (2º uso), no 6º dia foi aplicado 0,375 mg de Cloprostenol Sódico e no 8º dia, pela manhã, foram retirados os implantes, separados os bezerros e foi aplicado 0,5 mg de cipionato de estradiol. No dia 10º dia pela tarde procedeu-se a IATF. Neste momento, aleatoriamente, de cada duas vacas uma recebia 100μg de análogo sintético ao GnRH. Sete dias após a IATF os animais(AU)

The lack of estrous detection and the postpartum anestrous are the largest causes of the low fertility in the beef cattle herds. To minimize these problems one of the recommended biotechnology it is the use of the fixed-time artificial insemination (TAI). This work evaluated the use of GnRH at the moment of TAI and the postpartum days (PPD) on the reproductive performance. Data of the thirty two cows rearing calves were used. Fifty cows formed the group GnRH and 17 the group control. The PPD of the cows were in medium 74 days for occasion of TAI. The animals formed one homogeneous group being handled equally. All cows received in the day “0” 2 mg of estradiol benzoato and one intravaginal implant content progesterone of 2nd use. On the 6th day was applied 0,375 mg of sodic cloprostenol and in the 8th day, by the morning, the implants were take off and the calves were separated temporarily and were applied 0,5 mg of estradiol cipionate. On the 10th day at the afternoon TAI was done. At this time randomly, one of each two cows received 100 µg of synthetic analogue to GnRH. Seven days after TAI the animals were allocated into one field with more 35 cows and 2 clean-up bulls during 60 days. It was evaluated the effects on the GnRH application on the Pregnancy rate at TAI (PRTAI) and the pregnancy rate after clean-up bulls (PRB). The effects of the PPD were analyzed on the PRTAI and PRB. The PRTAI was of 46.7% and 35.3%, respectively for the cows of the groups GnRH and control (P>0.05). The PRB was of 53.3% and 64.7%, respectively for the cows of the group GnRH and control (P>0.05). There was not relationship by the use of GnRH with PRTAI and PRB. For analyze the PPD it was formed two groups. One group (14 cows) with average of 57 ± 18.4 PPD (PPD57) and other group (18 cows) with average of 88 ± 9.1 PPD (PPD88). In the groups PPD57 and PPD88 the PRTAI was respectively 42.9% and 38.9% (P>0.05); and the PRB was respectively 64.3% and 55.6% (P>0,05)(AU)

Dinâmica folicular de vacas de corte tratadas com três protocolos de sincronização da ovulação / Ovarian Follicular Dynamics in Beef Cows Treated with Three Protocols of Synchronization of Ovulation

Artificial insemination is an established and viable technique to accelerate the genetic advancement and economic return of the cattle. However, compromises the efficiency of detection of estrus results in low insemination rates. To avoid these problems in beef herd, synchronization protocols have been developed that allow inseminate large number of animals within a set period of time. These treatments are known as protocols for synchronization of ovulation for fixed-time artificial insemination (FTAI). There are several slow-release progesterone or progestins devices on the market for use in synchronization of estrus/ovulation programs in cattle, but these devices have a high cost, which results in less use of these protocols by farmers . This study aimed to determine the follicular dynamic of a low cost protocol to synchronize ovulation, which uses vaginal sponges impregnated with medroxy-progesterone acetate (MPA; group 1) and compare it with two trade protocols (groups 2 and 3).(AU)

Proteínas do plasma seminal relacionadas a congelabilidade do sêmen bovino / Seminal plasma proteins related to bovine semen freezabilty

A tecnologia da criopreservação tem apresentado desenvolvimento notório, tanto no melhoramento da qualidade como na fertilidade do sêmen após o processamento. Apesar dos progressos alcançados com as técnicas da criopreservação do sêmen, ainda são obtidas perdas em torno de 50% de espermatozóides viáveis durante o processo (Watson, 2000). Os indivíduos podem ser classificados como produtores de sêmen de alta e baixa congelabilidade, dependendo das características estruturais da membrana, o que é geneticamente determinado, predispondo à sobrevivência ao estresse da criopreservação (WATSON, 2000). Várias proteínas do plasma seminal bovino têm influência na congelabilidade do sêmen. Roncoletta (1999), através da análise das proteínas do plasma seminal, verificaram três polipepteptídeos (45, 24 e 10,8 kDa) com densidade óptica superior nas amostras de reprodutores de melhor congelabilidade do sêmen. Outras proteínas também foram relacionadas à alta congelabilidade do sêmen: a proteína ácida do fluído seminal bovino (aSFP), a clusterina, a albumina e a osteopontina (OPN); podendo assim, ser indicadas como marcadores. Também foram indicadas mais duas bandas protéicas (15-16 kDa, pI 4,7-5,2 e relacionadas à alta congelabilidade do sêmen, porém que não foram identificadas no estudo, mas que pelo peso molecular e ponto isoelétrico aproximado poderiam corresponder às proteínas BSP A1/A2 (15-16 kDa, pI 4,7-5,2) ou BSP A3 (13-14 kDa, pI 6,0-6,5) (JOBIM et al., 2004). Outros estudos indicam ainda as proteínas P25b e as proteínas anticongelação (AFPs), como proteínas relacionadas a congelabilidade do sêmen. Apesar dos progressos no conhecimento das proteínas relacionadas à criopreservação, ainda encontramos resultados bastante contraditórios e por vezes, a ausência do conhecimento da forma de proteção conferida por determinadas proteínas... (AU)

Cryopreservation techniques has shown remarkable development, both in improving the quality and the fertility of semen after processing. Despite these progress , losses are around 50% of viable sperm during the process (Watson, 2000). Individuals can be classified as producers of high-and low semen The structural characteristics of the membrane, which is genetically determined, predisposes the survival of the stress of cryopreservation (Watson, 2000). Several proteins of bovine seminal plasma influence on semen freezability . Roncoletta (1999), analysing seminal plasma proteins, find three polipepteptídeos (45, 24 and 10.8 kDa) with higher optical density in samples of the bulls with high freezability semen. Other proteins were also highly related to the frozen semen: the acid bovine seminal fluid (aSFP), the clusterin, the albumin and osteopontin (OPN) can be shown as semen freezability markers. Also two protein bands, (15-16 kDa, pI 4,7-5,2) are related to the high semen freezability, based in molecular weight and isoelectric point could correspond to the protein BSP A1/A2 (15-16 kDa, pI 4,7-5,2) or BSP A3 (13-14 kDa, pI 6,0-6,5) (JOBIM, et al 2004). Other studies also indicate the proteins P25b as antifreezeprotein (AFPs) related to semen freezability... (AU)

Marcadores protéicos de fertilidade no plasma seminal e na membrana plasmática / Protein markers of fertility in the seminal plasma and plasma membrane

A expectativa de dispor de marcadores que auxiliem a indicação do potencial reprodutivo animal tem sido objeto de inúmeras pesquisas nas últimas décadas, que provavelmente poderão contribuir significativamente na escolha de reprodutores superiores. Os resultados mais significativos envolvendo índices de fertilidade “in vivo” indicam proteínas candidatas a marcadores. Estes estudos foram realizados em reprodutores da raça Holandesa baseado nas taxas de não retorno de milhares de vacas submetidas a inseminações, utilizando doses de sêmen congelado, processadas segundo padrões metodológicos bem definidos (Moura et al., 2006a). Baseado nos experimentos recentes as seguintes proteínas são as principais candidatas a serem marcadores de fertilidade: osteopontina (OPN), prostaglandina D- sintase tipo lipocalina (PDGS), BSP-30 kDa, fosfolipase A2 (PLA-2), espermadesinas, proteínas de ligação à heparina, P25b e clusterina. Além destes marcadores, resultante de experimentos criteriosos baseados em taxas de não retorno em um número expressivo de animais sabe-se da existência de alguns outros marcadores, propostos como indicadores da fertilidade e descobertos muitas vezes ao acaso, e cujas funções até então são desconhecidas, portanto, o significado biológico de suas relações com a fertilidade ainda é desconhecido. (AU)

Labels that can help to indicate the potential breeding of animals has been the subject of many researches in recent decades, which probably could contribute significantly in the selection of males with superior breeding qualities. The in vivo findings involving fertility levels can indicate protein markers. These studies were performed in no return rates of Holstein breeding on thousands of inseminated cows, using doses of frozen semen, processed second methodological standards well defined (Moura et al., 2006a). Recent experiments based on proteins, like osteopontin (OPN), prostaglandin D synthase-type lipocalin (PDGS), BSP-30 kDa, phospholipase A2 (PLA-2), spermadesin, proteins heparin biniding, P25b and clusterin are the main candidates to be markers of fertility. In addition to these markers, the result of careful experiments based on no return rates in a significant number of animals is known of the existence of some other markers, proposed as indicators of fertility and often discovered occasionally, and whose functions and biological relationship with fertility are mostly unknown.(AU)

Marcadores protéicos de fertilidade no plasma seminal e na membrana plasmática / Protein markers of fertility in the seminal plasma and plasma membrane

A expectativa de dispor de marcadores que auxiliem a indicação do potencial reprodutivo animal tem sido objeto de inúmeras pesquisas nas últimas décadas, que provavelmente poderão contribuir significativamente na escolha de reprodutores superiores. Os resultados mais significativos envolvendo índices de fertilidade “in vivo” indicam proteínas candidatas a marcadores. Estes estudos foram realizados em reprodutores da raça Holandesa baseado nas taxas de não retorno de milhares de vacas submetidas a inseminações, utilizando doses de sêmen congelado, processadas segundo padrões metodológicos bem definidos (Moura et al., 2006a). Baseado nos experimentos recentes as seguintes proteínas são as principais candidatas a serem marcadores de fertilidade: osteopontina (OPN), prostaglandina D- sintase tipo lipocalina (PDGS), BSP-30 kDa, fosfolipase A2 (PLA-2), espermadesinas, proteínas de ligação à heparina, P25b e clusterina. Além destes marcadores, resultante de experimentos criteriosos baseados em taxas de não retorno em um número expressivo de animais sabe-se da existência de alguns outros marcadores, propostos como indicadores da fertilidade e descobertos muitas vezes ao acaso, e cujas funções até então são desconhecidas, portanto, o significado biológico de suas relações com a fertilidade ainda é desconhecido.

Labels that can help to indicate the potential breeding of animals has been the subject of many researches in recent decades, which probably could contribute significantly in the selection of males with superior breeding qualities. The in vivo findings involving fertility levels can indicate protein markers. These studies were performed in no return rates of Holstein breeding on thousands of inseminated cows, using doses of frozen semen, processed second methodological standards well defined (Moura et al., 2006a). Recent experiments based on proteins, like osteopontin (OPN), prostaglandin D synthase-type lipocalin (PDGS), BSP-30 kDa, phospholipase A2 (PLA-2), spermadesin, proteins heparin biniding, P25b and clusterin are the main candidates to be markers of fertility. In addition to these markers, the result of careful experiments based on no return rates in a significant number of animals is known of the existence of some other markers, proposed as indicators of fertility and often discovered occasionally, and whose functions and biological relationship with fertility are mostly unknown.

Proteínas do plasma seminal relacionadas a congelabilidade do sêmen bovino / Seminal plasma proteins related to bovine semen freezabilty

A tecnologia da criopreservação tem apresentado desenvolvimento notório, tanto no melhoramento da qualidade como na fertilidade do sêmen após o processamento. Apesar dos progressos alcançados com as técnicas da criopreservação do sêmen, ainda são obtidas perdas em torno de 50% de espermatozóides viáveis durante o processo (Watson, 2000). Os indivíduos podem ser classificados como produtores de sêmen de alta e baixa congelabilidade, dependendo das características estruturais da membrana, o que é geneticamente determinado, predispondo à sobrevivência ao estresse da criopreservação (WATSON, 2000). Várias proteínas do plasma seminal bovino têm influência na congelabilidade do sêmen. Roncoletta (1999), através da análise das proteínas do plasma seminal, verificaram três polipepteptídeos (45, 24 e 10,8 kDa) com densidade óptica superior nas amostras de reprodutores de melhor congelabilidade do sêmen. Outras proteínas também foram relacionadas à alta congelabilidade do sêmen: a proteína ácida do fluído seminal bovino (aSFP), a clusterina, a albumina e a osteopontina (OPN); podendo assim, ser indicadas como marcadores. Também foram indicadas mais duas bandas protéicas (15-16 kDa, pI 4,7-5,2 e relacionadas à alta congelabilidade do sêmen, porém que não foram identificadas no estudo, mas que pelo peso molecular e ponto isoelétrico aproximado poderiam corresponder às proteínas BSP A1/A2 (15-16 kDa, pI 4,7-5,2) ou BSP A3 (13-14 kDa, pI 6,0-6,5) (JOBIM et al., 2004). Outros estudos indicam ainda as proteínas P25b e as proteínas anticongelação (AFPs), como proteínas relacionadas a congelabilidade do sêmen. Apesar dos progressos no conhecimento das proteínas relacionadas à criopreservação, ainda encontramos resultados bastante contraditórios e por vezes, a ausência do conhecimento da forma de proteção conferida por determinadas proteínas...

Cryopreservation techniques has shown remarkable development, both in improving the quality and the fertility of semen after processing. Despite these progress , losses are around 50% of viable sperm during the process (Watson, 2000). Individuals can be classified as producers of high-and low semen The structural characteristics of the membrane, which is genetically determined, predisposes the survival of the stress of cryopreservation (Watson, 2000). Several proteins of bovine seminal plasma influence on semen freezability . Roncoletta (1999), analysing seminal plasma proteins, find three polipepteptídeos (45, 24 and 10.8 kDa) with higher optical density in samples of the bulls with high freezability semen. Other proteins were also highly related to the frozen semen: the acid bovine seminal fluid (aSFP), the clusterin, the albumin and osteopontin (OPN) can be shown as semen freezability markers. Also two protein bands, (15-16 kDa, pI 4,7-5,2) are related to the high semen freezability, based in molecular weight and isoelectric point could correspond to the protein BSP A1/A2 (15-16 kDa, pI 4,7-5,2) or BSP A3 (13-14 kDa, pI 6,0-6,5) (JOBIM, et al 2004). Other studies also indicate the proteins P25b as antifreezeprotein (AFPs) related to semen freezability...

Dinâmica folicular e uso de hormonioterapias na regulação do ciclo estral na vaca / Follicular dynamics and hormone therapy in the regulation of estrous cycle in cows

A máxima eficiência reprodutiva em rebanhos de bovinos de corte está asssociada à uma alta eficiência reprodutiva da vaca. Para tanto se faz necessário, entre outros, precocidade sexual, retomada da atividade ovariana precoce no pós-parto, assim como, parições o mais concentradas possível. As alternativas para a obtenção destas metas, envolvem além de técnicas de manejo, planos nutricionais e inclusive técnicas hormonioterápicas. As técnicas hormonioterápicas, em especial com o uso de progestágenos, estrógenos, gonadotrofinas, prostaglandinas e hormônios liberadores de gonadotrofinas, podem ser de utilidade, desde que sejam preenchidos requisitos básicos. (AU)

The maximum reproductive efficiency in beef cattle herds is associated with the high reproductive efficiency of the cows. For this is necessary, among others, sexual precocity, early resumption of ovarian activity in postpartum, as well concentrated parturitions. The alternatives to achieve these goals, involving management techniques, nutritional plans, can include hormone therapy techniques. The hormone therapy techniques, especially with the use of progestagen, estrogen, gonadotropins, prostaglandins and gonadotrophin releasing hormone may be useful, provided they met some basic requirements. (AU)

Dinâmica folicular e uso de hormonioterapias na regulação do ciclo estral na vaca / Follicular dynamics and hormone therapy in the regulation of estrous cycle in cows

A máxima eficiência reprodutiva em rebanhos de bovinos de corte está asssociada à uma alta eficiência reprodutiva da vaca. Para tanto se faz necessário, entre outros, precocidade sexual, retomada da atividade ovariana precoce no pós-parto, assim como, parições o mais concentradas possível. As alternativas para a obtenção destas metas, envolvem além de técnicas de manejo, planos nutricionais e inclusive técnicas hormonioterápicas. As técnicas hormonioterápicas, em especial com o uso de progestágenos, estrógenos, gonadotrofinas, prostaglandinas e hormônios liberadores de gonadotrofinas, podem ser de utilidade, desde que sejam preenchidos requisitos básicos.

The maximum reproductive efficiency in beef cattle herds is associated with the high reproductive efficiency of the cows. For this is necessary, among others, sexual precocity, early resumption of ovarian activity in postpartum, as well concentrated parturitions. The alternatives to achieve these goals, involving management techniques, nutritional plans, can include hormone therapy techniques. The hormone therapy techniques, especially with the use of progestagen, estrogen, gonadotropins, prostaglandins and gonadotrophin releasing hormone may be useful, provided they met some basic requirements.

Ácidos graxos poliinsaturados e seus efeitos no desempenho reprodutivo da vaca / Polyunsaturated fatty acids and their effects on the reproductive performance in the cow

Para alcançar máxima eficiência reprodutiva em um rebanho de bovinos de corte é necessário que todos os aspectos fisiológicos, nutricionais e de manejo estejam perfeitamente integrados e em pleno funcionamento. A rentabilidade na exploração de bovinos de corte é diretamente dependente da porcentagem de vacas que são capazes de obter um intervalo de partos em torno de 365 dias. Para que isto seja alcançado, entre outros, está com grande importância o equilíbrio nutricional. Pesquisas indicam que o aumento na concentração de ácidos graxos poliinsaturados na dieta em bovinos, como o linoléico e linolênico podem ter efeitos benéficos sobre a reprodução, em especial sobre a síntese de prostaglandinas e hormônios esteróides como a progesterona. (AU)

To achieve maximum reproductive efficiency in a beef cow herd is necessary that all the physiological aspects, nutrition and management are fully integrated and in full function. The profitability of beef cattle operation is directly dependent on the percentage of cows that are able to achieve a calving interval of around 365 days. To achieve this goal, is very important the nutritional balance. Different autors indicate that the increase in the concentration of polyunsaturated fatty acids in the diet in animals, such as linoleic and linolenic acids can have beneficial effects on reproduction, particularly on the synthesis of prostaglandins and steroid hormones such as progesterone. (AU)