RESUMO

To evaluate the effectiveness of progesterone ear devices new and second use, rates were determinedestrus and pregnancy rates in cycling and anestrous animals by breastfeeding. We used 69 dual-purposecows (Bos taurus by Bos indicus) with calf at foot and 60 to 80 days postpartum, a livestock farm, located inthe municipality of Cimitarra, Santander. The animals were implanted for 9 days with 3 mg of norgestomet(Crestar ® MSD), and were divided randomly into two groups, Group 1 (n=35) cows with new devices,Group 2 (n=34) cows with implants headset reused, and artificial insemination was performed at fixed timeat 56 hours after removal of the devices. The data obtained were tested in a simple ANOVA (ANOVA) with areliability of 95%. For the variable estrus no differences (p>0.05) between group 1 and 2 (66.4% and 53.4%),respectively. The variables pregnancy and ovarian structures (Dominant follicles and corpus luteum), uponsynchronization, yielded significant differences (p<0.05) between groups 1 devices new group (53.9,%) vs group2 devices reused (38,3%), ovarian structures and between group 1 devices new (56,6%) vs. group 2 devicesreused (33.2%) respectively, with ovaries without structures. We conclude that progesterone ear devices new andreused, generate similar rates of estrus. Also, pregnancy rates are higher in cows cycling versus anestrus cows.

Para evaluar la eficacia de los dispositivos auriculares de progesterona nuevos y de segundo uso, se determinaron las tasas de presentación de estros y porcentaje de preñez en animales ciclando y en anestro por amamantamiento. Se usaron 69 vacas doble propósito (Bos taurus por Bos indicus) con cría al pie y con 60 a 80 días postparto, de una explotación ganadera, ubicada en el municipio de Cimitarra, Santander. Losanimales fueron implantados durante 9 días, con 3 mg de Norgestomet ( Crestar ® MSD), y se dividieron en dosgrupos al azar, Grupo 1 (n= 35) vacas con dispositivos nuevos; Grupo 2 (n= 34) vacas con implantes auricularesreutilizados, y se realizó la inseminación artificial a tiempo fijo a las 56 horas posteriores al retiro de losdispositivos. Los datos obtenidos, fueron sometidos a prueba de Análisis de Varianza simple (ANOVA) con unaconfiabilidad del 95%. Para la variable presentación de estros no se encontraron diferencias (p>0,05), entre el grupo 1 y 2(66,4% y 53,4%), respectivamente. Las variables preñez y estructuras ováricas (Cuerpos Lúteos y folículosDominantes), al momento de la sincronización, arrojaron diferencias significativas (p<0,05) entre los grupos grupo 1 dispositivo nuevos (53.9%) vs grupo 2 dispositivo usados (38,3%), con estructuras ovaricas y entre el grupo 1 dispositivo nuevo (56,6%) vs Grupo 2 dispositivo usados (33,2%) respectivamente, con ovarios sin estructuras.Se concluye que los dispositivos auriculares de progesterona nuevos y de segundo uso, generan similares tasas de presentación de estros. Así mismo, los porcentajes de preñez son mayores en vacas ciclando frente a vacas en anestro.

Para avaliar a eficácia dos dispositivos auriculares de progesterona novos e de segundo uso, foramdeterminadas as taxas de apresentação de estros e porcentagem de gravidez em animais ciclando e em anestropor amamentação. Foram usadas 69 vacas duplo propósito (Bos taurus por Bos indicus) com cria ao pé e com60 a 80 dias postparto, de uma exploração de gados, localizada no município de Cimitarra, Santander. Osanimais foram implantados durante 9 dias, com 3 mg de Norgestomet ( Crestar ® MSD), e se dividiram emdois grupos na sorte, Grupo 1 (n= 35) vacas com dispositivos novos; Grupo 2 (n= 34) vacas com implantesauriculares reutilizados, e foi realizada a inseminação artificial há um tempo fixo às 56 horas posteriores ao retirodos dispositivos. Os dados obtidos foram submetidos à prova de Análise de Variação simples (ANOVA) com umaconfiabilidade de 95%. Para a variável apresentação de estros não foram encontradas diferenças (p>0,05), entreo grupo 1 e 2 (66,4% e 53,4%), respectivamente. As variáveis gravidez e estruturas ováricas (Corpos Lúteos efolículos Dominantes), ao momento da sincronização, jogaram diferenças significativas (p<0,05) entre os gruposgrupo 1 dispositivo novos (53.9%) vs grupo 2 dispositivo usados (38,3%), com estruturas ovaricas e entre o grupo1 dispositivo novo (56,6%) vs Grupo 2 dispositivo usados (33,2%) respectivamente, com ovários sem estruturas.Conclui-se então que os dispositivos auriculares de progesterona novos e de segundo uso geram similares taxas deapresentação de estros. Assim, as porcentagens de gravidez são maiores em vacas ciclando frente a vacas em anestro.

Assuntos

RESUMO

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.

Assuntos

RESUMO

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)

Assuntos

RESUMO

The estrus behavior was evaluated during an induced and natural subsequent estrus in twelve Guzera breed cows, in the winter and summer seasons in two consecutive years. The proportion of cows that responded to estrus synchronization was 84.8 percent. The effect of the interaction season x year of experiment on estrous cycle length was observed. Pro-estrus was longer in the summer (57.69±4.72h) and in the natural estrus (74.23±4.41h) than in the winter (38.95±4.02h) and in the induced estrus (22.40±4.36h). Estrus length was similar in the winter (11.48±0.70h) and in the summer seasons (13.40±0.82h) as well as among cows with induced (12.47±0.75h) and natural estrus (12.41±0.76h). The number of mounts accepted during estrus and the number of mounts accepted/ hour in estrus were similar in winter (29.17±2.86 and 2.59±0.22, respectively) and summer (31.45±3.36 and 2.42±0.26, respectively) as well as between induced (30.23±3.10 and 2.54±0.24, respectively) and natural estrus (30.40±3.14 and 2.47±0.24, respectively). The length and intensity of estrus were not influenced by synchronization or season of the year. Longer period of pro-estrus in summer may favor the identification of sexually active animals in this season.

A manifestação do comportamento estral foi avaliada durante um estro induzido e o estro subseqüente, em 12 vacas da raça Guzerá, no inverno e no verão em dois anos consecutivos. A proporção de vacas que respondeu à sincronização de estros foi de 84,8 por cento. Observou-se efeito de interação entre estação e ano sobre a duração do ciclo estral. O proestro foi maior no verão (57,69±4,72h) e no estro natural (74,23±4,41h), que no inverno (38,95±4,02h) e no estro induzido (22,40±4,36h). A duração do estro foi similar no inverno (11,48±0,70h) e no verão (13,40±0,82h), assim como entre as vacas com estro induzido (12,47±0,75h) e natural (12,41±0,76h). O número de montas recebidas durante o estro e o número de montas recebidas/hora em estro foram similares no inverno (29,17±2,86 e 2,59±0,22, respectivamente) e no verão (31,45±3,36 e 2,42±0,26, respectivamente), assim como entre o estro induzido (30,23±3,10 e 2,54±0,24, respectivamente) e o natural (30,40±3,14 e 2,47±0,24, respectivamente). A duração e a intensidade do estro não foram influenciadas pela sincronização ou pela estação do ano. O maior período de proestro no verão pode favorecer a identificação dos animais sexualmente ativos.

RESUMO

This research was aimed at verifying the pregnancy rate in beef heifers submitted to a protocol for estrus induction and synchronization on the parturition period and its effect on the repetition of pregnancy at the second reproductive season. The experimental animals where composed of 194 Hereford and Braford heifers divided in two groups. The treatment group included a protocol of estrus observation and synchronization and fixed-time insemination (FTAI). The control group was submitted to a conventional artificial insemination management, with estrus observation and insemination in the next turn. Both groups were submitted to a natural mating period with clean-up bulls. The heifers were also observed as primiparous on the next reproductive season. The pregnancy rate was 91.7% in the first season for both groups. In the treatment group, 82% of the treated cows calved on the first 40 days of the groups calving season, against 51.7% of the control animals, resulting in a better conception rate in treated heifers (73 vs. 55%) in the second breeding season. The estrus synchronization and FTAI management on the first breeding season of beef heifers produce better pregnancy results also on the second breeding season.

O objetivo deste trabalho foi verificar o índice de prenhez em novilhas de corte submetidas a um protocolo de indução e sincronização de estros sobre a cronologia das parições e seu efeito sobre a repetição de crias na estação reprodutiva subseqüente como vacas primíparas. Foram utilizadas 194 novilhas Hereford e Braford divididas em dois grupos. O grupo tratamento constou de um protocolo misto de observação e sincronização de estros e inseminação artificial a tempo fixo (IATF). O grupo controle foi submetido ao manejo convencional de inseminação artificial, com observação de estros e inseminação no turno seguinte. Ambos os grupos foram submetidos a repasse com touros. A porcentagem de prenhez na primeira estação reprodutiva para os dois grupos foi de 91,7%. No grupo tratamento, 82% das vacas pariram dentro dos primeiros 40 dias da estação reprodutiva, contra 51,7% dos animais controle. A repetição de crias nas primíparas do grupo tratamento em comparação às do controle foi significativamente maior (73% x 55%). O manejo com sincronização de estros e IATF na primeira estação monta em novilhas, apesar de apresentar índices idênticos de prenhez ao final da temporada, proporcionou, porém, diferença significativa nos índices de prenhez na segunda estação reprodutiva.

RESUMO

This research was aimed at verifying the pregnancy rate in beef heifers submitted to a protocol for estrus induction and synchronization on the parturition period and its effect on the repetition of pregnancy at the second reproductive season. The experimental animals where composed of 194 Hereford and Braford heifers divided in two groups. The treatment group included a protocol of estrus observation and synchronization and fixed-time insemination (FTAI). The control group was submitted to a conventional artificial insemination management, with estrus observation and insemination in the next turn. Both groups were submitted to a natural mating period with clean-up bulls. The heifers were also observed as primiparous on the next reproductive season. The pregnancy rate was 91.7% in the first season for both groups. In the treatment group, 82% of the treated cows calved on the first 40 days of the groups calving season, against 51.7% of the control animals, resulting in a better conception rate in treated heifers (73 vs. 55%) in the second breeding season. The estrus synchronization and FTAI management on the first breeding season of beef heifers produce better pregnancy results also on the second breeding season.

O objetivo deste trabalho foi verificar o índice de prenhez em novilhas de corte submetidas a um protocolo de indução e sincronização de estros sobre a cronologia das parições e seu efeito sobre a repetição de crias na estação reprodutiva subseqüente como vacas primíparas. Foram utilizadas 194 novilhas Hereford e Braford divididas em dois grupos. O grupo tratamento constou de um protocolo misto de observação e sincronização de estros e inseminação artificial a tempo fixo (IATF). O grupo controle foi submetido ao manejo convencional de inseminação artificial, com observação de estros e inseminação no turno seguinte. Ambos os grupos foram submetidos a repasse com touros. A porcentagem de prenhez na primeira estação reprodutiva para os dois grupos foi de 91,7%. No grupo tratamento, 82% das vacas pariram dentro dos primeiros 40 dias da estação reprodutiva, contra 51,7% dos animais controle. A repetição de crias nas primíparas do grupo tratamento em comparação às do controle foi significativamente maior (73% x 55%). O manejo com sincronização de estros e IATF na primeira estação monta em novilhas, apesar de apresentar índices idênticos de prenhez ao final da temporada, proporcionou, porém, diferença significativa nos índices de prenhez na segunda estação reprodutiva.