Cláudio Alves Pimentel

Influence of Insulin-Like Growth Factor-I and Its Interaction with Gonadotropins, Estradiol, and Fetal Calf Serum on In Vitro Maturation and Parthenogenic Development in Equine Oocytes

Abstract The effects of insulin-like growth factor-I (IGF-I) and its interaction with gonadotropins, estradiol, and fetal calf serum (FCS) on in vitro maturation (IVM) of equine oocytes were investigated in this study. We also examined the role of IGF-I in the presence or absence of gonadotropins, estradiol, and FCS in parthenogenic cleavage after oocyte activation with calcium ionophore combined with 6-dimethylaminopurine (6-DMAP), using cleavage rate as a measure of cytoplasmic maturation. Only equine cumulus-oocyte complexes with compact cumulus and homogenous ooplasm (n = 817) were used. In experiment 1, oocytes were cultured in TCM-199 supplemented with BSA, antibiotics, and IGF-I at 0 (control), 50, 100, 200 ng/ml, at 39°C in air with 5% CO2, 95% humidity for 36 or 48 h. In experiment 2, oocytes were cultured with FSH, LH, estradiol, and FCS with IGF-I at the concentration that promoted the highest nuclear maturation rate in experiment 1. In experiment 3, oocytes from the three experimental groups (IGF-I; hormones; and IGF-I + hormones) were chemically activated by exposure to calcium ionophore followed by culture in 6-DMAP. In experiment 1, IGF-I stimulated equine oocyte maturation in a dose-dependent manner with the highest nuclear maturation rate at a concentration of 200 ng/ml. No significant effect of IGF-I on nuclear maturation was observed in experiment 2. In experiment 3, a significant difference in cleavage rate was observed between the hormone + IGF-I group (15 of 33; 45.4%) compared with IGF-I (10 of 36; 27.8%) and hormone (4 of 31; 12.9%) alone (P < 0.05). These results demonstrated that IGF-I has a positive effect on nuclear maturation rate of equine oocytes in vitro. The addition of IGF-I to an IVM medium containing hormones and FCS did not increase nuclear maturation, but resulted in a positive effect on cytoplasmic maturation of equine oocytes measured by parthenogenic cleavage.

Eficiência produtiva e reprodutiva em vacas leiteiras

The present study was conducted to evaluate the effects of post partum disorders on productive and reproductive performance of Holstein cows, from a dairy experimental station, during 24 years. Productive and reproductive data were collected from 350 cows. Analyses of variance was conducted to evaluate the effects of occurrence of post partum disorders (abortion, stillbirth, dystocia, retained placenta) and mastitis on calving interval (IEP), calving to conception interval (IPC), calving to first estrus interval (IPPC), number of estrus before conception (NC) and milk production (PL). The mean age at first estrus was 29.4 months and the mean age at first calving was 37.1 months. Mean IEP was 14.6 months, mean IPPC was 97.04 days and median IPC was 150.71 days. Median interestrus interval was 24 days, suggesting problems in a estrus detection. A significant effect of occurrence of abortion (P<0.05) was observed on IEP. Calving intervals were 258 days longer in the cows that aborted than in the ones that did not abort. The occurrence of stillbirth (P<0.01) and dystocia (P<0.05) significantly increased IEP in 82.4 days and 136.1 days, respectively. The IPPC was not affected by any of the diseases considered. Milk production was affected by dystocia (P<0.05). Cows that had dystocia produced 380.5kg less milk than normal calving cows. We concluded that preventive procedures to control herd health, criterious clinical diagnosis of post partum disorders and development of data bases with precise recordings for regular analysis of the productive and reproductive parameters may lead to a more economic dairy production.

Relationship between clinical and postmortem evaluation in repeat breeder beef cows

The objective of this study was to investigate the causes of the repeat breeder syndrome comparing clinical signs and postmortem findings in beef cows. The identification of factors affecting the reproductive tract can support decisions as to whether treatment of repeat breeder cows is justifiable than culling. Since all animals were submitted to clinical examination before being slaughtered, this study has a differential approach when compared with others, where genital tracts from abattoir were examined. In this study, 130 crossbred cows and heifers that have failed to conceive after three or more services were identified, submitted to a clinical examination and blood collection for karyotyping and sent to an abattoir. postmortem examinations included macroscopic evaluation of the genital tracts, bacteriology and histopathology of the uterus. Uterine alterations were predominant followed by oviduct and ovarian pathologies. Histopathological examination was more sensitive as a diagnostic tool than clinical examination. Repeat breeder cows had a predominance of uterine abnormalities (95%), such as inflammatory (42.9%) and degenerative (59.7%) conditions. Oviduct abnormalities were found in 29.8 % of animals. Furthermore, 1 out 10 karyotyped cows showed aneuploidy. Thus, this study stressed the importance of laboratory exams in the diagnosis of the causes of infertility of repeat breeder cows.

Postpartum reproductive performance of beef cows in moderate body condition submitted to estrus induction/synchronization

To assess the reproductive performance of beef cows submitted to estrus induction/synchronization, 42 Aberdeen Angus cows with body condition 3 (1-5 scale) under extensive management were used. The milk production was estimated through the weight-suckling-weight method. For gynecological examinations, ultrasound equipment and trans-rectal palpation were used. The milk production level (above and below the average production of cows), pregnancy, prebreeding reproductive condition (CRPA), surface anoestrus (uterine tone, follicles > 10 mm and absence of CL) and deep anoestrus (no uterine tone, follicles <10 mm and absence of CL) and the estrus induction/synchronization response (RISC) were considered as constant factors. The variables analyzed were the pre-delivery, delivery weight, mating and conception weights, weaning weight, the average daily weight gain from birth to weaning and total milk production. The prebreeding reproductive condition influenced the pre-birth and birth weights, showing that the better pre-birth and birth performance favors the restoration of reproductive activity in cows with moderate body condition (CC) in the post-partum period. The classification of the pre-breeding reproductive condition in beef cows can be a resource to determine the reproductive performance of beef cows submitted to estrus induction/synchronization, since cows in surface anoestrus tend to have better response to the protocol. In beef cows with moderate body condition, the pre-birth weight performance affects the prebreeding reproductive condition, increasing the likelihood of better reproductive performance.To assess the reproductive performance of beef cows submitted to estrus induction/synchronization, 42 Aberdeen Angus cows with body condition 3 (1-5 scale) under extensive management were used. The milk production was estimated through the weight-suckling-weight method. For gynecological examinations, ultrasound equipment and trans-rectal palpation were used. The milk production level (above and below the average production of cows), pregnancy, prebreeding reproductive condition (CRPA), surface anoestrus (uterine tone, follicles > 10 mm and absence of CL) and deep anoestrus (no uterine tone, follicles <10 mm and absence of CL) and the estrus induction/synchronization response (RISC) were considered as constant factors. The variables analyzed were the pre-delivery, delivery weight, mating and conception weights, weaning weight, the average daily weight gain from birth to weaning and total milk production. The prebreeding reproductive condition influenced the pre-birth and birth weights, showing that the better pre-birth and birth performance favors the restoration of reproductive activity in cows with moderate body condition (CC) in the post-partum period. The classification of the pre-breeding reproductive condition in beef cows can be a resource to determine the reproductive performance of beef cows submitted to estrus induction/synchronization, since cows in surface anoestrus tend to have better response to the protocol. In beef cows with moderate body condition, the pre-birth weight performance affects the prebreeding reproductive condition, increasing the likelihood of better reproductive performance.

Características seminais e fertilidade em garanhões

O objetivo deste experimento foi verificar o efeito da qualidade seminal e sua relacao com a fertilidade no garanhao. Os dados foram obtidos de sete haras, incluindo 1198 eguas, 2013 ciclos e 3817 servicos, durante tres temporadas consecutivas. A porcentagem de prenhez (P), porcentagem de prenhez por ciclo (P/C) e de servico (P/S), estimadas para cada garanhao, foram usadas como variaveis dependentes. Adicionalmente, verificou-se o efeito da idade ( 15 anos) e categoria reprodutiva da egua (lactacao, falhada ou virgem), sobre os indices reprodutivos. Garanhoes com total de espermatozoides viaveis no ejaculado superior a 1,8 x 109, motilidade nao inferior a 50% e percentual de normais acima de 60% (n=20) apresentaram melhor P (86% vs. 74%, p<0,01), P/C (54% vs. 45%), p<0,01) e P/S (28% vs. 22%, p<0,01) em relacao aos garanhoes cujas caracteristicas foram inferiores (n=16). O percentual de espermatozoides normais correlacionou-se a P (0,33), P/C (0,50) e P/S (0,36), respectivamente. Alem de a qualidade seminal, a idade e a categoria reprodutiva das eguas afetaram a fertilidade do garanhao. Esses resultados levam a conclusao de que a qualidade seminal interfere na fertilidade do garanhao; entretanto, outros fatores associados ao manejo reprodutivo, como a idade e a categoria reprodutiva das eguas, sao importantes na relacao entre qualidade seminal e fertilidade.

Desempenho reprodutivo de vacas de corte em lactação e solteiras submetidas à indução/sincronização de estro

Com o objetivo de caracterizar o desempenho produtivo e reprodutivo de duas categorias de vacas de corte submetidas a inducao/sincronizacao de estro, foram utilizadas 42 vacas em lactacao e 60 vacas solteiras da raca Aberdeen Angus, de tamanho similar e condicao corporal moderada (CC3, escala de 1 a 5), manejadas exclusivamente em campo nativo, no periodo de setembro de 2005 a abril de 2006 no municipio de Acegua/RS. Para os exames ginecologicos durante o experimento, foi utilizado aparelho de ultra-som e palpacao retal. Como fator fixo, foi considerada a categoria das vacas (CATV), considerando-se tres grupos, vacas solteiras ciclicas (VSC), ou seja, femeas que falham em conceber e permanecem na propriedade ate o proximo acasalamento, vacas em lactacao em anestro superficial (VLAS) e vacas em lactacao em anestro profundo (VLAP). Como variaveis resposta, foram considerados peso das vacas pre-acasalamento (PPRA), pos-acasalamento (PPOA), a concepcao (PC), o ganho de peso medio diario durante o acasalamento (GMD), resposta ao protocolo de inducao/sincronizacao de cio (RISC) e gestacao. A categoria da vaca demonstrou efeito (P<0,0001) sobre as variaveis de peso, em que as VSC apresentaram um melhor desempenho ponderal do que VLAS e VLAP. A RISC demonstrou ser altamente influenciada (P<0,0001) pela categoria de vaca, em que 85, 45 e 35% das vacas responderam a inducao/sincronizacao de cio nos grupos VSC, VLAS e VLAP, respectivamente. A gestacao apresentou diferenca (P<0,0001) entre VSC e vacas em lactacao, com 96,7, 45,5 e 30,0%, nos respectivos grupos VSC, VLAS e VLAP. Vacas solteiras apresentam um desempenho reprodutivo superior ao de vacas em lactacao, evidenciado pela maior resposta ao protocolo de inducao/sincronizacao de estro e indice de gestacao. Contudo, 24% das vacas em lactacao parecem estar bem adaptadas ao sistema de producao, demonstrando um desempenho produtivo e reprodutivo satisfatorio a producao de bovinos de corte, sendo capazes de produzir adequadamente leite para o desenvolvimento dos terneiros, bem como conceber e produzir novamente um terneiro. A identificacao desses animais pode influenciar positivamente o desempenho reprodutivo de vacas de corte em lactacao.

Fertilidade em garanhões avaliada através do exame andrológico

This paper discuss certain aspects of the fertility in stallions and its relationship to the Breeding Soundness Examination. In afirst analysis, 10 stallions that were bred only naturally had their reproductive standards correlated to the semen quality. In a second step, we consider 14 stallions that were bred either by artificial insemination and for naturally. In a third study, certain subfertile stallions, belonging to the previous two groups, had their fertility standards correlated to semen quality and management procedures. A significam association (P<0.01) was observed between semen quality (sperm morphology) and fertility, when stallions were bred naturally under appropriate management procedures. This relationship was not observed when artificial insemination was included in the management, because it can improve the fertility of subfertile stallions or be detrimental to normal stallions when misused used. The individual analysis of the subfertile stallions allowed to determine if the cause the infertility can befrom intrinsic or extrinsic (management) factors.

Gonadotrofina coriônica eqüina: purificação, caracterização e resposta ovariana em ovinos e suínos

Equine chorionic gonadotrophin (eCG) was purified and characterized with respect to its purity and bionological activity. The purity of four preparations was determined by electrophoresis, and the biological activity by increasing of the ovarian weight ot immature female rats (40-50g) and induction ot ovulation of ewes and gilts. Electrophoretic analysis revealed three polipeptidic bands. The mean biological activity was 313UI/mg of protein. Sixty-five ewes, not in reproductive season, were divided randomly in two groups that received vaginal pessaries impregnated with medroxiprogesterone acetato for 11 to 14 days. In treatment I, ewes (n = 55) were injected (IM) with 500UI of puritied eCG at the moment of pessaries withdraw, while in treatment II, the ewes (n = 10) received 500UI of comercial eCG. The results observed were 2.1 ± 0.3 and 1.8 ± 0.3 ovulations (P > 0.05) for treatments I and II, respectively. One hundred-twenty gilts, with mean weight of 87.2kg, were divided m two treatments. The animals in treatment I (90 gilts) received 500UI of puntied eCG and, 72 hours later, 500UI of hCG (human chorionic gonadotrophin). In treatment II hormones were not injected. The results observed were 25.9 ± 22.2 and 0.0 corpora lutea (P < 0.001) for treatments I and II, respectively. These results demonstrated that the eCG purified has purity and biological activity similar to the comercial product used as control, and that it is efficient in inducing ovarian activity in ewes and gilts.

Diferentes níveis de gordura na dieta de vacas Jersey em lactação influenciam a resposta superovulatória

This experiment aims at evaluating the effects of dietary fat to lactating dairy cows, on the superovulatory response and embryo quality. Eighteen high producing lactating Jersey cows (420±70.6kg of live weight, 22.2±1.7kg of milk/day) were grouped according to calving date and lactation order, and randomly assigned to one of the three treatment diets. The control group received a basic diet with corn and soybean bran, containing 4.0% ether extract, the medium group received the control diet with additional tallow to increase the ether extract content to 6.0% and the high group treatment received the control diet with additional tallow to increase the ether extract content to 8.0%. All cows were twice superovulated, at 90 and 130 days postpartum. The structures recovered (7 days after artificial insemination) were evaluated for developmental stage and quality grade (IETS, 1999). The results shows no difference on structures number, embryos grade one and two, grade four and corpora lutea number, for the tested treatments. The cows groups that receive high fat diet (2.9±0.4) had higher number of grade three embryos in relationship to control (0.2±0.4) and medium (0.0±0.5) groups. Addition of tallow to diets to increase EE levels to lactating cows did not increase the superovulatory response and embryo quality.

Fertility in the stallion as accessed by the spermatozoa morphology

In a breeding farm, 129 mares were bred to 4 stallions and had an overall pregnancy rate of 76.7%. Stailions were submitted to semen examination for at least two times at the beginning of the breeding season and the percentage of morphologically normal spermatozoa were used for statistical analysis in relation to the percentage of pregnancy at the end of the breeding season. A regression analysis revealed that the percentage of pregnancy (y) can be estimated by the percentage of normal spermatozoa (x) in the ejaculate according to the following equation: y=52.38+0.44x; r2=97.8%; P<0.01. We concluded that the pregnancy rate can be estimated by the percentage of morphologically normal spermatozoa in the ejaculate of stallions, since it is an importam characteristic of the semen quality that is strongly associated with fertility, in conditions of uniform management procedures for mares and stallions.