Este estudo avaliou os efeitos da administração de diferentes doses de eCG em dois momentos distintos no protocolo de sincronização da ovulação para inovulação em tempo fixo. No dia 0, as receptoras foram tratadas com dispositivo intravaginal contendo progesterona (DIP) e 2,0 mg de Benzoato de Estradiol (BE) associados a 50 mg de progesterona (P4) IM. A partir desse momento, os animais foram divididos homogeneamente para receberem 0,15 mg de d-cloprostenol (PGF2&#945;) e 400, 500 ou 600 UI de eCG no dia 5 (G-400d5, n=101; G-500d5, n=98; G-600d5, n=100, respectivamente) ou no dia 8 (G-400d8, n=100; G-500d8, n=99; G-600d8, n=96, respectivamente; fatorial 3x2). O DIP foi retirado no dia 8 e foi administrado 1 mg de BE no dia 9. No dia 17 os animais foram submetidos a ultra-sonografia ovariana e os que apresentaram mais que um corpo lúteo (CL) ou CL único maior que 18 mm de diâmetro receberam um embrião produzido in vitro. Em um grupo de animais, colheu-se amostras de sangue no dia 17 para determinação da concentração plamática de P4 (CPP4). Os animais tratados com eCG no dia 5 apresentaram maior taxa de aproveitamento [87,0 (260/299) vs. 81,7% (241/295), P<0,05], tendência de maior taxa de concepção [51,8 (132/255) vs. 45,0% (108/295), P=0,07], maior taxa de prenhez [44,1 (132/299) vs. 36,6% (108/295), P<0,05], maior número de CL (1,74 ± 0,09 vs. 1,13 ± 0,03, P<0,05) e maior proporção de receptoras com CL único de maior tamanho [CL 22: 65,7 (111/169) vs. 43,1% (94/218), P<0,05] que os tratados no dia 8. Não se observou efeito de dose sobre a taxa de aproveitamento [400: 82,1 (165/201) vs. 500: 83,8 (165/197) vs. 600: 87,2% (171/196), P<0,05], de concepção [400: 51,8 (85/164) vs. 500: 44,1 (71/161) vs. 600: 49,4% (84/170), P<0,05], de prenhez [400: 42,3 (85/201) vs. 500: 36,0 (71/197) vs. 600: 42,9% (84/196), P<0,05] e sobre a quantidade de receptoras com CL único de maior tamanho [400: 46,8 (65/139) vs. 500: 54,9 (73/133) vs. 600: 57,4 (66/115), P<0,05]. Os animais tratados com 600 UI de eCG apresentaram maior número de CL que os que receberam 400 ou 500 UI (400: 1,17 ± 0,03 vs. 500: 1,33 ± 0,06 vs. 600: 1,82 ± 0,12, P<0,05). No grupo que se determinou a CPP4 verificou-se que os animais que receberam eCG no dia 5 apresentaram maiores CPP4 que os do dia 8 (4,68 ± 0,43 vs. 2,73 ± 0,17 ng/ml, P<0,05). As novilhas tratadas com 600 UI de eCG apresentaram maiores CPP que as tratados com 400 ou 500 UI (400: 2,96 ± 0,22 vs. 500: 3,45 ± 0,38 vs. 600: 4,69 ± 0,55, P<0,05). Receptoras com mais de 1 CL apresentaram tendência de menores perdas gestacionais entre 30 e 60 dias de gestação que as com CL único [10,2 (4/49) vs. 17,5% (33/189), P=0,0547]. Os resultados são indicativos de maior eficiência do protocolo de sincronização da ovulação para transferência de embriões em tempo fixo com o uso de eCG no dia 5. A dose de eCG não influenciou na eficiência do tratamento / The aim of this study was to compare the effects of different doses of eCG administrated at two moments in a fixed-time embryo transfer protocol. On day 0, the heifers received a progesterone releasing vaginal insert (PRVI) and an injection of 2.0 mg Estradiol Benzoate (EB) associated with 50 mg progesterone (P4) i.m. The animals were randomly assigned to six treatment groups in a tree by two factorial design to receive 0.15 mg d-cloprostenol (PGF2&#945;) i.m. and 400, 500 or 600 IU eCG on day 5 (G-400d5, n=101; G-500d5, n=98; G-600d5, n=100, respectively) or on day 8 (G-400d8, n=100; G-500d8, n=99; G-600d8, n=96, respectively). On day 8, the PRVI was removed and an injection of 1 mg EB was administered on day 9. On Day 17, all heifers were examined by ultrasonography to determine the number of CL and those with more than one CL or a single CL with a diameter ?18 mm received an in vitro produced embryo. A subset of heifers were bled on day 17 for plasma P4 determination. The animals treated with eCG on day 5 presented higher proportion of heifers selected/treated [87.0 (260/299) vs. 81.7% (241/295), P<0.05], tendency to higher proportion of heifers pregnant/transferred [51.8 (132/255) vs. 45.0% (108/295), P<0.1], higher proportion of heifers pregnant/treated [44.1 (132/299) vs. 36.6% (108/295), P<0.05], higher CL number (1.74 ± 0.09 vs. 1.13 ± 0.03, P<0.05) and higher proportion of recipients with larger single CL [CL 22: 65.7 (111/169) vs. 43.1% (94/218), P<0.05] than those treated with eCG on day 8. Dose effects were not observed in the proportion of heifers selected/treated [400: 82.1 (165/201) vs. 500: 83.8 (165/197) vs. 600: 87.2% (171/196), P<0.05], pregnant/transferred [400: 51.8 (85/164) vs. 500: 44.1 (71/161) vs. 600: 49.4% (84/170), P<0.05], pregnant/treated [400: 42.3 (85/201) vs. 500: 36.0 (71/197) vs. 600: 42.9% (84/196), P<0.05] and proportion of recipients with larger single CL [400: 46.8 (65/139) vs. 500: 54.9 (73/133) vs. 600: 57.4 (66/115), P<0.05]. The animals that received 600 IU eCG presented higher CL number than those received 400 and 500 IU (400: 1.17 ± 0.03 vs. 500: 1.33 ± 0.06 vs. 600: 1.82 ± 0.12, P<0.05). In a subset of heifers that was performed a plasma P4 determination, the group that received eCG on day 5 presented higher plasmatic P4 concentration than those received eCG on day 8 (4.68 ± 0.43 vs. 2.73 ± 0.17 ng/ml, P<0.05). The use of 600 IU eCG presented higher plasmatic P4 concentration than 500 and 600 IU (400: 2.96 ± 0.22 vs. 500: 3.45 ± 0.38 vs. 600: 4.69 ± 0.55, P<0.05). Recipients with more than 1 CL tended to present lower pregnancy losses between 30 and 60 days than those with a single CL [10.2 (4/49) vs. 17.5% (33/189), P=0.0547]. The results suggest higher efficiency in the synchronization of ovulation protocol for fixed-time embryo transfer with eCG administration on day 5. The dose of eCG did not affect the efficiency of treatment

Compararam-se as taxas de prenhez (TP) em vacas Nelore (Bos taurus indicus) utilizando implantes de norgestomet novos ou reutilizados associados ao valerato de estradiol (VE) e benzoato de estradiol (BE). Duzentos e quarenta e uma vacas Nelore amamentando foram separadas em dois grupos, e receberam implante auricular contendo 3 mg de norgestomet (n=122) ou implante de norgestomet (n=119) que já havia sido previamente utilizado por 10 dias. Os animais que receberam implante novo ou reutilizado, foram sub-divididos, e um lote recebeu uma injeção (IM) de 3 mg de norgestomet associados a 5 mg de valerato de estradiol e o outro, uma injeção (IM) de 50 mg de progesterona associados a 2 mg de benzoato de estradiol. No momento da retirada do implante todos os animais receberam 1 aplicação de análogo de PGF2&alpha; (IM) para assegurar a luteólise e 24 h após uma injeção de 1,0 mg de BE (IM). A inseminação artificial em tempo fixo (IATF) ocorreu 54-56 h após a retirada do implante. Não houve interação entre tipo de implante e tipo de éster de estradiol para TP IATF nem TP Final. As TP IATF não diferiram entre animais que receberam implante novo ou reutilizado (48,3 vs 48,7%) nem entre os que receberam VE ou BE (49,5 vs 47,5%). O mesmo ocorreu para TP Final segundo tipo de implante, novo ou reutilizado (85,2 vs 86,5%) e segundo tipo de éster de estradiol, VE ou BE (86,5 vs 85,2%). Conclui-se que vacas Nelore amamentando podem apresentar adequadas TP IATF e TP Final quando tratadas por implantes de norgestomet novos ou reutilizados associados indistintamente ao valerato ou benzoato de estradiol. / Pregnacy rates (PR) were compared in Nelore cows (Bos taurus indicus) using new or used norgestomet implants associated to estradiol valerate (EV) and estradiol benzoate (EB). Two hundred forty one Nelore cows were synchronized and divided in two groups, they received auricular implants with 3 mg of norgestomet (n=122) or used norgestomet implants (n=119) previously used for 10 days. The animals that received new or used implants were sub-divided and received an administration (im) of 3 mg of norgestomet plus 5 mg of EV and another group received an administration of 50 mg of progesterone plus 2 mg of EB. When the implant was removed a dose of PGF2&alpha; analogous was given for all animals to assure luteolysis and 24 h later they received (im) of 1,0 mg of EB. The fixed-timed artificial insemination (AIFT) occurred 54-56 h after implant withdrawal. There was no difference between the two implants as well as no diffrence to EV or EB, neither PR AITF nor PR Finish. The PR AIFT did not differ among animals that received that received new or used implants (48,3 vs 48,7%) neither EV nor EB (49,5 vs 47,5%). The same happened to PR Finish either new or used (85,2 vs 86,5%) when EV or EB (86,5 vs 85,2%) were used. In this present study, it was concluded that Nelore suckling cows can show a regulated PR AIFT and PR Finish after treatments with new or used norgestomet implants associated to EV or EB.

A pesquisa desenvolvida no Laboratório de Pesquisa em Suínos, da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, Campus de Pirassununga, estudou os efeitos de diferentes doses de LH suíno exógeno na indução e sincronização da puberdade em marrãs. Sessenta e sete fêmeas Camborough - 22 Agroceres PIC® com 140 dias de idade e 86 kg de peso vivo foram submetidas aos seguintes tratamentos: controle T1 (n = 21) - emprego de 600 UI de eCG (gonadotrofina coriônica eqüina) (Novormon&reg) e 72 horas depois 5,0 mg de LH (hormônio luteinizante) (Lutropin® - V); tratamento 2 T2(n = 23) - 600 UI de eCG (Novormon®) e, 72 horas depois, 2,5 mg de LH (Lutropin® - V) e tratamento 3 T3(n=23) - 600 UI de eCG (Novormon®) e, 72 horas depois, 1,25 mg de LH (Lutropin® - V). O estímulo com macho adulto era feito duas vezes ao dia, sendo a ovulação detectada pela ultra-sonografia transcutânea e a taxa de ovulação, pela contagem do número de corpos lúteos (CL) ao abate. O percentual de estro foi semelhante entre T1 (42,85%), T2 (60,87%) e T3 (52,18%), não havendo diferença estatística significativa (P=0,418). O percentual de fêmeas com degenerações císticas foi de 33,33% (T1); 39,13%(T2) e 39,13%(T3), não havendo diferença significativa entre os tratamentos (P=0,9057). O melhor intervalo tratamento - ovulação (LH - OV) ocorreu no grupo de fêmeas submetidas ao T2 (38,26 ± 2,84) demonstrado pela menor dispersão dos desvios comparando com T1 (37,17 ± 4,07) e T3 (36,25± 5,69), sendo o valor do desvio padrão diferente estatisticamente do de T3, porém igual ao valor de T1 sendo ainda o valor de T1 igual ao de T3(P<0,05). O intervalo entre a aplicação de eCG e estro do T1(85,33 ± 12,64 horas), T2 (84,40 ±17,50 horas) e T3 (89,14 ± 14,66 horas) foram semelhantes não havendo diferença estatística significativa (P= 0,6954). A duração do estro foi semelhante entre os três tratamentos (P = 0,2653), sendo de 41,44 ± 16,30 horas (T1); 48,57 ± 16,29 horas (T2); 39,33 ± 11,42 horas (T3). O número de Corpos Lúteos em T1 foi de 9,61 ± 5,43 (1-25); em T2 de 9,86 ±3,32 (1-16); em T3 de 8,13 ± 5,52 (0-20), não constatando diferença significativa (P=0,4259). Os menores desvios observados no tratamento T2 sugerem que a combinação de 600 UI de eCG seguida por 2,5 mg de LH após 72 horas, foi a mais efetiva na indução e sincronização do estro e ovulação em fêmeas suínas pré-púberes, considerando a metodologia experimental empregada. Na segunda parte do experimento, foram realizadas inseminações artificiais em tempo fixo em dois esquemas (E) diferentes: O (E1) recebeu uma única dose 36 h após a aplicação de LH e, o (E2) recebeu a primeira dose 24 h e a segunda dose 36 h após a aplicação de LH. As marrãs foram abatidas com 5 dias de gestação e os embriões foram colhidos. Não verificou-se diferença estatística entre os valores obtidos na taxa de recuperação (36,81±5,21 para E1 e 36,91±4,62 para E2), taxa de viabilidade embrionária (TVE) (59,28±6,91 para E1 e 62,25±6,26 para E2), taxa de fecundação (TF) (72,60±7,06 para E1 e 79,33±6,26 para E2) e número de estruturas totais (3,41±0,57 para E1 e 3,77±0,50 para E2) entre E1 e E2. Houve interação significativa entre tratamento e número de doses de sêmen para as variáveis TVE (T1=60,51± 8,18, T2=68,64±7,94 e T3=53,14±7,8) e TF (73,50±8,36 para T1, 89,93±8,11 para T2 e 64,46±8,05 para T3) (P=0,0036). Novos estudos envolvendo aplicação dos hormônios e n° de doses de sêmen, necessitam serem repetidos. / The research carried out at the Swine Research Laboratory, of FMVZ - USP, Campus of Pirassununga, studied the effects of the use of different hormonal doses on the induction and synchronization of puberty in gilts. Sixty-seven Camborough 22 Agroceres PIC® females with 140 days of age and 86kg of body weight were submitted to the following treatments: control T1 (n=21) - use of 600 IU of eCG (equine chorionic gonadotrophin) (Novormon®) and 72 hours later 5,0 mg of LH (Luteinizing hormone) (Lutropin® - V); treatment 2 T2 (n = 23) - 600 UI of eCG (Novormon®) and 72 hours later 2,5mg of LH (Lutropin® - V) and treatment 3 T3 (n = 23) - 600 UI of eCG (Novormon®) and 72 hours later 1,25mg of LH (Lutropin® - V). Adult boar stimulation was implemented twice a day, and ovulation was detected through transcutaneous ultrasonography and ovulation rate by corpora lutea (CL) counting at slaughter. The percentage of estrus was similar in T1 (42,85%), T2 (60,87%) and T3 (52,18%), and there was no significant statistic difference (P=0,418). The percentage of females with cystic degeneration was 33,33% (T1); 39,13%(T2) and 39,13%(T3), being no significant difference between the treatments (P=0,9057). The best interval between treatment and estrus (LH - OV) occurred in the group of females submitted to T2 (38,26 ± 2,84) demonstrated by lesser dispersion of the deviations comparing to T1 (37,17 ± 4,07) and T3 (36,25± 5,69); standard deviation was statistically different from T3, but similar to T1, and T1 was also similar to T3 (P<0,05). The interval between the administration of eCG and estrus in T1 (85,33 ± 12,64 hours), T2 (84,40 ±17,50 hours) and T3 (89,14 ± 14,66 hours) were similar, and there was no significant statistic difference (P= 0,6954). The duration of estrous was similar among the three treatments (P = 0,2653), being 41,44 ± 16,30 hours (T1); 48,57 ± 16,29 hours (T2); 39,33 ± 11,42 hours (T3). The number Corpus Luteum in T1 was 9,61 ± 5,43 (1-25); in T2 was 9,86 ±3,32 (1-16); in T3 was 8,13 ± 5,52 (0-20), and there was no significant difference (P=0,4259). The minor deviations observed in treatment T2 suggest that the association of 600 UI of eCG followed by 2,5 mg of LH after 72 hours, was more effective in the induction and synchronization of estrous and ovulation in pre-puberty female swine, considering the experimental methodology used. In the second part of the experiment, artificial insemination was performed at determined timing following two different programs (E). E1 received a single dose 36 hours after administration of LH and E2 received the first dose after 24 hours and the second dose 36 hours after the administration of LH. The gilts were slaughtered with 5 days of pregnancy and the embryos were collected. No statistic difference was observed among the values obtained for recovery rate (36,81±5,21 for E1 and 36,91±4,62 for E2), embryonary viability rate (TVE) (59,28±6,91 for E1 and 62,25±6,26 for E2), fecundation rate (TF) (72,60±7,06 for E1 and 79,33±6,26 for E2) and number of total structures (3,41±0,57 for E1 and 3,77±0,50 for E2) among E1 and E2. There was significant interaction between treatment and the number of doses of semen for the values TVE (T1=60,51± 8,18, T2=68,64±7,94 and T3=53,14±7,8) and TF (73,50±8,36 for T1, 89,93±8,11 for T2 and 64,46±8,05 for T3) (P=0,0036). New research involving the use of hormones and the number of doses of semen need to be repeated.

O estradiol secretado pelo folículo dominante (DOM) desempenha importante papel na luteólise da vaca. Em adição, o reconhecimento materno da prenhez (MRP) requer um ambiente uterino otimizado, o qual por sua vez depende da função luteínica e de adequadas concentrações de progesterona circulante. Os objetivos do presente estudo foi testar diferentes estratégias para otimizar a função luteínica e prevenir a influência de um DOM durante o período crítico (CP) para o MRP (de D13 a D20 após o estro o estro). Diferentes abordagens foram testadas. No exp.1, 23 vacas Nelore foram tratadas com o protocolo ovsynch para induzir um cio sincronizado (D0). As vacas receberam: Gc (n=7) - nada mais; ThCG (n=5) - 3000 IU de hCG no D5; TE2 (n=6) - 5mg de 17b-estradiol (E2) no D12; ThCG/E2 (n=5) - hCG/D5 + E2/D12. Ultra-sonografias e dosagens de progesterona plasmática durante o ciclo estral permitiram determinar que o E2 reprogramou o ciclo ovariano ao prevenir a presença (P&it;0,05) de um DOM durante quase todo CP (0,6&plusmn;0,7 dias entre D15 e D20), porém o E2 induziu a luteólise. As vacas que receberam a hCG desenvolveram corpo lúteo acessório e tiveram [P4] mais alta até o D13 (P&it;0,05). Portanto, a fase luteínica não foi prolongada No exp.2, os mesmos tratamentos foram impostos a 220 vacas Nelore (55 por grupo) após uma inseminação artificial em tempo fixo (TAI). As taxas de prenhez (PR) à TAI ou às inseminais de repasse durante uma estação com 64 dias de duração foram diminuídas (P&it;0,05) quando o E2 foi usado e a hCG não foi capaz de aumentar aquelas PR. No exp.3, vacas Red Angus no pós-parto tiveram seu estro sincronizado (D0) e receberam: nada mais (GCT, n=5) ou 200mg de gonadorrelina no D5 mais 3000 IU hCG no D13 (GRF, n=5); ou ablação de todos folículos &sup3;7mm através de aspiração folicular em D14, D17 e D20 (GRM, n=5). GRF teve luteólise retardada (18,2&plusmn;1,0b dias, 23,6&plusmn1,0a dias e 18,7&plusmn1,2b dias para GCT, GRF e GRM, respectivamente) e maior [P4] que os outros grupos. Folículos maiores que 7mm foram observados quando das aspirações. Foi possível concluir que: a) E2 permitiu consistentemente reprogramar o desenvolvimento folicular, porém causou luteólise e o seu uso trouxe efeitos negativos sobre as PR; b) a hCG melhorou a função luteínica mas não aumentou as PR; c) a ablação dos folículos &sup3;7mm não preveniu a presença do DOM no CP para o MRP e d) a associação GnRH/hCG otimizou a função luteínica, retardou a luteólise e prolongou a fase luteínica de modo que todo o CP esteve sob influência da progesterona / Estradiol secreted from the dominant follicle (DOM) plays a key role in triggering luteolysis in the cow. In addition, maternal recognition of pregnancy (MRP) requires an optimum uterine environment, which directly depends on luteal function and adequate levels of circulating progesterone. The aim of this study was to test different strategies to optimize luteal function and prevent the influence of a DOM throughout the critical period (CP) for MRP (from D13 to D20 after estrus). Different approaches were tested. In exp.1, 23 Nelore cows were treated with the ovsync protocol to induce a synchronized estrus (D0). Cows received: Gc (n=7) - nothing else; ThCG (n=5) - 3000 IU of hCG five days (D5) after estrus; TE2 (n=6) - 5mg of 17b-estradiol (E2) on D12; ThCG/E2 (n=5) - hCG/D5 + E2/D12. Ultrasound evaluation and plasmatic progesterone concentration ([P4]) throughout estrous cycle allowed to conclude: E2 reprogrammed ovarian cycle by preventing the presence (P&it;.05) of a DOM during almost all CP (0.6±.7 days within the D15 to D20 interval) but induced luteolysis; cows receiving hCG developed accessory corpus luteum and had higher [P4] up to D13 (P&it;.05). Therefore, luteolysis was not delayed and luteal phase was not prolonged. In exp.2, same treatments were imposed to 220 Nelore cows (55 per group) after a timed artificial insemination (TAI). Pregnancy rates (PR) at TAI or at AIs thereafter over a 64-day period were reduced (P&it;0.05) by using E2 and hCG was not capable to improve those PR. In exp.3, postpartum Red Angus cows were estrus synchronized (D0) and received: nothing else (GCT, n=5) or 200mg of gonadorrelin on D5 plus 3000 IU hCG on D13 (GRF, n=5); or ablation of all follicles &sup3;7mm through follicular aspiration on D14, D17 and D20 (GRM, n=5). GRF had delayed luteolysis (18.2&plusmn;1.0b days, 23.6&plusmn;1.0a days, 18.7&plusmn;1.2b days for GCT, GRF, GRM, respectively) and higher [P4] than other groups. Follicles larger than 7mm were observed in all occasions of aspiration. In could be concluded that: a) E2 allowed to consistently reschedule follicular development but caused luteolysis and its use was detrimental to PR; b) hCG improved luteal function but did not increase PR; c) ablation of 7mm follicles did not prevent a DOM throughout CP for MRP and d) GnRH/hCG association optimized luteal function, delayed luteolysis and prolonged luteal phase in such a way that all CP was under progesterone influence

Esta tese está fundamentada em dois experimentos que visam colaborar na elucidação dos efeitos das afecções de casco sobre o desempenho reprodutivo de vacas leiteiras no Brasil. No experimento 1, um total de 57 vacas Holandesas no início da lactação foi utilizado para avaliar os efeitos das afecções de casco sobre o comportamento no estro. Os animais foram classificados de acordo com o escore dos cascos e o escore da locomoção, identificando-se assim animais com os cascos sadios e animais que apresentam lesões nos cascos. Todos os animais foram sincronizados com prostaglandina (Cloprostenol sódico). O comportamento destas vacas durante o estro foi monitorado por um aparelho de radiotelemetria (HeatWatchâ). Os dados relativos ao casco (variáveis independentes) foram associados com os seguintes dados relativos ao estro: número de montas, soma da duração das montas, duração média das montas, intensidade das montas e duração do estro (variáveis dependentes). Os resultados evidenciaram significância estatística apenas na relação funcional entre a variável dependente Duração do estro e a variável independente Escore de locomoção (P=0,0237; R²=0,0921). Quando foram considerados dois grupos, em função da presença do acometimento do casco, foi possível, utilizando a análise de variância, demonstrar diferença significativa com as variáveis Número de montas (P=0,0363); Soma da duração das montas (P=0,0280) e Duração do estro (P=0,0071). No experimento 2, 1447 vacas Holandesas foram utilizadas para avaliar a associação entre a incidência de claudicação e o desempenho reprodutivo. As vacas foram monitoradas desde o parto até a concepção, avaliando-se a relação entre a incidência de claudicação e os índices reprodutivos, compreendendo: intervalo do parto ao primeiro cio, ao primeiro serviço e à concepção; percentual de vacas com e sem claudicação que conceberam no primeiro serviço; número de doses por concepção e percentual de vacas com e sem claudicação vazias com mais de 210 dias de lactação. Os resultados demonstraram que no intervalo do parto ao primeiro cio houve diferença significativa (P=0,0021) de 16 dias; (P=0,0150) de 21 dias; (P=0,0027) de 26 dias e (P=0,0279) de 29 dias na data do cio quando a claudicação ocorreu no segundo mês, no terceiro mês, no quarto mês e no sexto mês da lactação, respectivamente. No intervalo do parto ao primeiro serviço houve diferença significativa (P=0,0159) de 13 dias; (P=0,0021) de 15 dias e (P=0,0044) de 17 dias na data do primeiro serviço quando a claudicação ocorreu no segundo mês, no terceiro mês e no quarto mês da lactação, respectivamente. No intervalo do parto à concepção e no número de doses por concepção não houve diferença significativa (P>0,05) entre os animais que apresentaram e que não apresentaram claudicação. Do total de 1447 vacas, 21,9% conceberam no primeiro serviço, sendo que 17% apresentaram claudicação e 82,6% não apresentaram; e 26% do total de vacas permaneceram vazias por mais de 210 dias em lactação, sendo que 68% apresentaram claudicação e 31,9% não apresentaram / This study is based in two experiments which aim to evaluate the effects of lameness on the reproductive performance of dairy cows in Brazil. In experiment 1,57 Holsteins cows in the beginning of the lactation were divided according to the hoof and locomotion score, respectively, and the incidence of lameness or not (healthy cows). All cows did receive were syncronized by prostaglandine (cloprostenol sódico) and its behavior during the estrus was monitored by a radiotelemetria device (HeatWatchâ). Following to this, it was possible to monitor the possible association of the lameness and the following data to the estrus: number of mounts, total duration of the mounts, duration average of the mounts, intensity of the mounts and the duration of the estrus. The results were statistically significant between the dependent variable estrus duration and the independent variable locomotion score (P=0,0237; R²=0,0921). While considering two groups, due to lameness, it was possible via the variance analysis to show the significant difference with the variable number of mountains (P=0,0363); sum of mountain duration (P=0,0280) and estro duration (P=0,0071). In experiment 2, 1447 Holsteins cows from 5 different farms were monitored from the calving date till the conception, where it was evaluated the relationship between the lameness incidence and the reproductive records, understanding: calving interval till first heat, first service and until conception; percentage of cows with and without lameness that were pregnant in the first service; number of dosis per conception and percentage of open cows over 210 days in milk with and without lameness. The results demonstrated that from the calving date till the first heat a significant difference of 16 days more (P=0,0021), 21 days more (P=0,0150), 26 days more (P=0,0027) and 29 days more (P=0,0027) when the lameness did happen in the second, third, fourth and sixth month of lactation, respectively. About the interval from the calving until the first insemination, a significant difference occurred in 13 days more (P=0,0159), 15 days more (P=0,0021) and 17 days more (P=0,0044) when the lameness did happen in the second, third and fourth months, respectively. In relation to the interval from calving to conception and the number of dose per conception, it was not found significant difference (P>0,05) between the animals with and without lameness. >From the total 1447 cows, 21,9% did get pregnant in the first service and from this animals, 17% did have lameness and 82,6% did not. Also, 26% of the total cows were open for more than 210 days in milk, and from this 68% did have lameness and 31,9% did not have lameness

Grandes avanços tem sido feitos para melhorar a produção de leite, mas estes avanços têm resultado numa queda geral da eficiência reprodutiva. Para se combater esta queda, tem sido seguidos principalmente três caminhos: um relacionado com a vaca, outro com as gametas e outro com o ambiente. Os problemas associados à vaca compreendem os problemas relacionados com a detecção de cio e os problemas hormonais que resultam em baixas taxas de concepção e aumento das mortes embrionárias precoces. Alternativas para melhorar a detecção de cio tem sido procuradas, dentre estas, os medidores de atividade são uma alternativa promissória, porém ainda em desenvolvimento. Com o fim de avaliar a eficiência do uso de medidor de atividade na detecção de cio de vacas leiteiras de alta produção, foram desenvolvidos três experimentos. O primeiro avaliou a eficiência do uso de medidor de atividade na detecção de cio após o período de espera voluntario (PEV), o segundo avaliou a eficiência do uso de medidor de atividade na detecção do cio de retorno após o uso de um protocolo de inseminação artificial a tempo fixo (IATF), o terceiro avaliou a relação custo-benefício da aquisição do aparelho. Na detecção do primeiro cio efetivo após o PEV o medidor de atividade apresentou maior taxa de detecção de cio, comparado com a observação visual de cio. O aparelho mostrou especial avantaja sobre a observação visual de cio na detecção de vacas multíparas de alta produção. No experimento de detecção de cio de retorno após o uso de IATF, o medidor de atividade detectou maior número de animais em menor tempo, porém, as mudanças no padrão de comportamento animal causadas pelos hormônios próprios da sincronização de cio, diminuíram a confiabilidade do sistema automatizado de detecção, ainda assim o numero de animais detectados em cio verdadeiro do sistema automatizado foi superior. Na análise de custo-benefício, a taxa interna de retorno obtida, demonstrou que o medidor de atividade é um investimento rentável o que possibilita sua aquisição. Enquanto aos falsos positivos gerados pelo sistema, sugere-se integrar as indicações feitas pelo sistema automatizado com a experiência dos funcionários das fazendas. / Huge progress has been made to improve the milk yield, but these advances have resulted in a general decrease of reproductive efficiency. Three main ways have been taken to combat this decrease: one related to the cow, another with the gametes and the lasts related with the environment. The problems associated with cow comprehend the estrous detection problems and the hormonal disorders that results in low conception rates and increases the early embryonic deaths. Alternatives to improve the heat detection has been developed. Among them, the activity meters are a promissory alternative, but still in development. Three experiments were developed in order to assess the efficiency of use of an activity meter in the estrous detection of high producing dairy cows. The first assessed the efficiency of the use of activity meter detecting estrous after the voluntary waiting period (VWP), the second assessed the efficiency of use of activity meter in the detection of the return estrous after use of a fixed-time artificial insemination (TAI) protocol, the third assessed the cost-benefit of acquisition of the system. In the first estrous after the VWP, the activity meter presented higher estrous detection rate, compared with the visual observation. The system has special vantage in the detection of multiparous high producing cows, if compared with visual observation. In the experiment of detecting return estrous after use of TAI, the activity meter detected greater number of animals in less time, however, changes in the pattern of animal behavior caused by hormones during the synchronization, decreased the accuracy of the automated system. On the other hand, the number of animals detected in real estrous of the automated system was superior than in visual observation. In the cost-benefit analysis, the internal rate of return obtained, showed that the activity meter is a profitable investment. Referent to the false positives generated by the system, it is suggested to integrate the indications made by the automated system with the experience of the functionaries of the dairy farms.

This research was conducted at the La Raya experiment station, Cusco, Peru (4200 m elevation, 15°S latitude, and 70°W longitude) using 60 Corriedale, and 60 Criollo ewes during three consecutive years (April 1981 - March 1984). Age, and weight at puberty, age at physical maturity, and the effects of breed, age (physically immature and mature), year, and month were measured on body weight, incidence of estrus, and incidence and rate of ovulation. There was a significant difference (P.05). Even though Criollo e wes weighed less than Corriedale, they attained puberty earlier, and showed less seasonality in estrus and ovulated throughout the year than the Corriedale.

Bibliography: leaves 182-210.

Ziel der vorliegenden Arbeit war die ausführliche histomorphologische Charakterisierung der endometrialen Funktionsmorphologie sowie die Darstellung der Ki-67 Antigen, Östrogen- und Progesteronrezeptor-Expression am Endometrium zyklischer und azyklischer Maultierstuten unter Einbeziehung klinischer und endokrinologischer Daten. Die Ergebnisse sollten mit den zu diesem Thema bereits vorliegenden Erkenntnissen bei der Pferdestute verglichen werden. Zu diesem Zweck wurden 97 Endometriumbioptate von sechs klinisch-gynäkologisch gesunden Maultierstuten im Alter von 13 bis 23 Jahren (immun-)histologisch ausgewertet. Die Bioptate waren zuvor in Abständen von zwei bis zehn Tagen und über einen Zeitraum von 4 Monaten (April bis August 2004), im Fall einer Stute von sieben Monaten (April bis November 2004) entnommen worden. Für jedes der Tiere lagen detaillierte Informationen über die klinisch-gynäkologischen Befunde und die Serumhormonkonzentrationen zu den entsprechenden Entnahmezeitpunkten vor (BARTMANN et al. 2008). Vorberichtlich zeigen zwei der Tiere im Untersuchungszeitraum ein unregelmäßiges Zyklusgeschehen mit ovariellen Funktionskörpern sowie variablen Serumöstradiol- und –progesteronkonzentrationen, bei vier Maultieren wird klinisch eine Azyklie mit inaktiven Ovarien sowie niedrigen, wenig schwankenden Serumhormonwerten dokumentiert. Bei den Tieren der zyklischen Gruppe (n=2) variiert die endometriale Funktionsmorphologie sehr stark. In nahezu allen untersuchten Endometriumbioptaten findet sich eine ausgeprägte endometriale Fehldifferenzierung. Diese kann anhand ihres Erscheinungsbildes nach den bei der Pferdestute bekannten histomorphologischen Kriterien (HÄFNER 1999, SCHOON et al. 1999b) eingeteilt werden. Sie tritt bei den untersuchten Maultieren als irreguläre glanduläre oder aber als irreguläre und ungleichmäßige glanduläre Differenzierung in Erscheinung und wird mit einem inaktiven, sekretorischen oder proliferativen Grundcharakter vorgefunden. Maultierstute 1 zeigt im Untersuchungszeitraum eine variable endometriale Proliferationsaktivität (Marker Ki-67 Antigen), bei Maultierstute 2 ist sie konstant schwach ausgeprägt. Es lässt sich kein charakteristisches, zyklusphasenabhängiges, positiv an die Steroidhormonrezeptorexpression gekoppeltes Expressionsmuster, wie es bei der Pferdestute bekannt ist, nachweisen. Die ER- und PR-Expression zeigt bei den zyklischen Maultierstuten ein sehr variables Bild (insbesondere Maultierstute 1), welches dem bei zyklierenden Pferdestuten während der physiologischen Decksaison nicht entspricht. Aufgrund der Diskrepanz zwischen klinischen Daten, Serumhormonkonzentrationen, endometrialer Funktionsmorphologie und Hormonrezeptorstatus bei den zyklischen Maultierstuten kann festgestellt werden, dass es bei den untersuchten Tieren nicht möglich ist, anhand der morphologisch-funktionellen Gegebenheiten am Endometrium auf den klinischen Zyklusstand zu schließen und vice versa. Die erhobenen Befunde sind in ihrer Gesamtheit am ehesten vergleichbar mit den Verhältnissen bei Pferdestuten in den Übergangszyklen zwischen Winteranöstrus und physiologischer Decksaison. Bei der Gruppe der azyklischen Maultiere (n=4) findet sich in allen untersuchten Endometriumbioptaten eine inaktive endometriale Funktionsmorphologie. Diese passt grundsätzlich zu dem klinischen Vorbericht der Azyklie mit inaktiven Ovarien und niedrigen, wenig schwankenden Serumöstradiol- und -progesteronkonzentrationen. In der Mehrzahl der Bioptate liegt eine Irregularität der glandulären Epithelien vor und in einigen Fällen treten hyperplastische und hypersekretorische Drüsenareale auf. Diese Befunde können, anlehnend an die Erkenntnisse bei der Pferdestute, als Kennzeichen einer endometrialen Fehldifferenzierung interpretiert werden (HÄFNER 1999, SCHOON et al. 1999b). Im Zusammenhang mit der schwachen endometrialen Proliferationsaktivität und der variablen ER- und PR-Expression lässt sich eine deutliche Ähnlichkeit zu den Befunden bei Pferdestuten im Winteranöstrus bzw. im Anöstrus während der physiologischen Decksaison finden (AUPPERLE et al. 2003, GOCKELN et al. 2006). Die möglichen Ursachen der endometrialen Fehldifferenzierung bei den Maultierstuten können im Rahmen der durchgeführten Untersuchungen nicht abschließend geklärt werden. Es ist jedoch denkbar, dass, analog zur Pferdestute, eine ovariell oder zentral bedingte Dysregulation und/oder eine Störung auf der Effektor/Rezeptor-Ebene vorliegen können. Die Hauptursache für die Infertilität bei Maultierstuten besteht in den chromosomal bedingten Störungen im Ablauf der Meiose der Keimzellen (WODSEDALEK 1916). Aufgrund der eigenen Untersuchungsergebnisse kann jedoch angenommen werden, dass die diagnostizierte endometriale Fehldifferenzierung, die variable Steroidhormonrezeptor-Expression sowie das Vorliegen degenerativer endometrialer Alterationen, z.B. der Endometrose, in Anlehnung an die Erkenntnisse bei der Pferdestute, zusätzliche Faktoren darstellen könnten, die zur Unfruchtbarkeit der Maultiere beitragen. Die Ergebnisse der vorliegenden Arbeit beruhen jedoch lediglich auf der Untersuchung von sechs Maultierstuten und sollten aus diesem Grund nicht unkritisch auf die Gesamtpopulation der Maultiere übertragen werden. Weitere Verlaufsuntersuchungen an einem größeren Tiergut in verschiedenen Altersgruppen inkl. Betrachtung der Hypophysenhormone FSH und LH könnten zur Aufklärung der Ursache sowie der Bedeutung der endometrialen Fehldifferenzierung für die Infertilität beim Maultier beitragen. / The aim of the present study was a detailed histomorphological characterization of the functional morphology and the evaluation of Ki-67 antigen, estrogen and progesterone receptor expression patterns in the endometrium of cyclic and non-cyclic mule mares, with respect to clinical and endocrinological data. The results were to be compared with corresponding observations in the endometrium of horse mares. For this purpose 97 endometrial biopsies from six clinically and gynaecologically healthy mule mares, aged between 13 and 23 years, were evaluated histologically and immunohistochemically. The biopsies were taken in intervals from two up to ten days over a period of four months (April to August 2004), in one mare over seven months (April to November 2004). Detailed information was given about clinical and gynaecological findings. The serum hormone concentrations for each day of biopsy sampling were determined (BARTMANN et al. 2008). According to the clinical record two of the animals show an erratic estrous cycle associated with the occurrence of corpora lutea and follicles on the ovaries during the whole period of investigation. Additionally, variable plasma estrogen and progesterone values are found. Four mules reveal acyclia including inactive ovaries and constant low serum hormone levels. In the animals of the cyclic group (n=2) the endometrial functional morphology varies to a great extend. In almost every investigated endometrial biopsy a marked endometrial maldifferentiation can be detected. It is classified according to common histomorphological criteria used for the endometrium of horse mares (HÄFNER 1999, SCHOON et al. 1999b). Endometrial maldifferentiation of the mules investigated occurs as irregular glandular or irregular and unequal differentiation and appeares in combination with a proliferative, secretory or inactive functional morphology. Mule 1 shows variable and mule 2 constant low endometrial Ki-67 expression patterns during the period of investigation. In contrast to horses, no characteristic, stage of cycle- or steroid hormone receptor expression-dependent proliferation activity can be observed with the mule mares of the present study. The expression of estrogen and progesterone receptors is highly variable in the animals of the cyclic group (especially in mule 1). These findings do not correspond to the ones in horse mares during the physiological breeding season. Due to the discrepancy between clinical data, serum hormone values, endometrial functional morphology and hormone receptor expression in the investigated mules, a conclusion from the clinical stage of cycle to morpho-functional conditions in the endometrium and vice versa seems to be impossible. The results of the present study are most likely comparable with findings in horse mares during the transitional period between winter anestrus and the physiological breeding season. The mules of the acyclic group (n=4) reveal an inactive endometrial functional morphology in all investigated endometrial biopsies. This finding basically corresponds to the clinical record of acyclia associated with inactive ovaries and rather constant serum estrogen and progesterone concentrations. In the case of these animals a majority of the investigated endometria show irregular glandular epithelia. In some areas hyperplastic and hypersecretory glands can be seen. According to observations in horse mares these findings can be interpreted as signs of endometrial maldifferentiation (HÄFNER 1999, SCHOON et al. 1999b). In connection with the weak proliferation activity and the variable ER- and PR-expression patterns seen in the acyclic mules, these results resemble findings in horses during winter anestrus or anestrus during the breeding season (AUPPERLE et al. 2003, GOCKELN et al. 2006). Within the present study the possible reasons for endometrial maldifferentiation in mules could not be finally evaluated. But it seems possible that, like in horse mares, an ovarian or central dysregulation and/or dysfunction regarding the level of receptors and effectors could play a certain role. Infertility in she-mules is mainly due to the chromosomal abnormalities during meiosis of germ cells (WODSEDALEK 1916). According to the findings in horse mares, the results of this investigation indicate that the diagnosed endometrial maldifferentiation, the variable expression of steroid hormone receptors and the presence of endometrial degenerative lesions (e.g. endometrosis) could be additional factors that possibly lead to sterility in mule mares, too. Due to the small number of individuals examined in this study, the results should not uncritically be applied to the whole population of mules. Further clinical, histological and immunohistochemical investigations, including the pituitary hormones FSH and LH as well as the use of a larger number of animals at different stages of age, could lead to a better understanding of the causes of endometrial maldifferentiation and its relevance for the infertility in mules.

Bibliography: leaves 182-210 / vii, 210 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Dept. of Obstetrics and Gynaecology, University of Adelaide, 1985