Memoria para optar al Título Profesional de Médico Veterinario. / Con el objetivo de comparar los efectos de las dos preparaciones comerciales de somatotrofina bovina recombinante (bSTr) existentes en el mercado, sobre la producción de vacas lecheras, se utilizaron 348 vacas Holstein de una lechería de alta producción en confinamiento permanente, ubicada en la comuna de Casablanca, Región de Valparaíso. Las vacas fueron asignadas aleatoriamente a partir de los 70-76 DEL para formar dos grupos de tratamiento. Un grupo (n=161) fue tratado con el preparado hormonal Boostin® (LG LifeSciences, Corea del Sur) y el otro (n=187) con Lactotropina® (Elanco, USA). En ambos grupos la hormona se administró cada 14 días hasta aproximadamente 30 días antes de la fecha de secado. Se obtuvo información de los programas Afimilk® y DairyCOMP®, recolectándose hasta el término del octavo ciclo de tratamiento (aproximadamente 180 DEL). La producción de leche se analizó mediante un análisis de varianza para medidas repetidas. La fertilidad al primer servicio se evaluó mediante un análisis de regresión logística para evaluar el riesgo de preñez a la primera inseminación. Los días a la preñez se analizaron por un análisis de sobrevida de Kaplan-Meier. Las frecuencias de mastitis clínica se compararon por prueba de chi–cuadrado. El riesgo de ocurrencia de mastitis se determinó por un análisis de regresión logística. Los recuentos mensuales de células somáticas se analizaron a través de análisis de varianza para medidas repetidas. Finalmente, la velocidad de eliminación fue evaluada mediante un análisis de sobrevida de Kaplan-Meier. No se presentaron diferencias significativas en la producción de leche, promediando los grupos tratados con Boostin® y Lactotropina® 42,3 L/día y 42,8 Litros/día, respectivamente (p=0,07). No se registraron diferencias significativas en el lapso parto-preñez durante los primeros 180 días de lactancia (p=0,19), presentando una mediana de 101 días el grupo tratado con Lactotropina® y de 90 días en las vacas tratadas con Boostin®. La tasa de concepción al primer servicio fue de 40% en vacas tratadas con Boostin® y de 32,8% en vacas tratadas con Lactotropina® (p=0,16). Tampoco se observaron diferencias significativas en el riesgo de obtención de preñez al primer servicio (p>0,05). Vacas tratadas con Lactotropina® presentaron mayor incidencia de mastitis clínica durante el ensayo (33,5%) en comparación al grupo tratado con Boostin® (21,1%) (p=0,01) y mostraron el doble de probabilidad de presentar esta patología durante el tratamiento (p=0,007). En cuanto al SRCS en leche, tampoco se observaron diferencias significativas (p=0,9), promediando los grupos tratados con Boostin® y Lactotropina® un SRCS de 2,43±0,08 y 2,4±0,07, respectivamente. Finalmente, los tratamientos no tienen efecto sobre la velocidad de eliminación (p=0,78). En conclusión, no existen diferencias sustanciales entre los preparados hormonales respecto de producción de leche, sanidad mamaria y fertilidad. / In order to compare the effect of two commercial preparations of Recombinant bovine Somatotropin (rbST) on the production of dairy cows, 348 Holstein cows from a high-producing dairy farm, in a confined system located in Casablanca, Valparaíso Region, were used. Cows were randomly assigned from 70-76 days in milk (DIM) to one of two treatment groups. One (n= 161) was treated with the hormonal preparation Boostin® (LG LifeSciences, South Korea) and the other (n=187) with Lactotropina® (Elanco, USA). In both groups, the hormone was administered every 14 days to about 30 days before dry off. Information was obtained from Afimilk® and DairyCOMP® computer programs, collected until the end of the eighth cycle of treatment (approximately 180 DIM). Milk data was processed through a repeated measures analysis of variance. Fertility at first insemination was analyzed by logistic regression to evaluate the risk of pregnancy at first insemination. Days open were analyzed with Kaplan-Meier survival analysis to compare days at pregnancy. Frequencies of clinical mastitis were compared by chi–square test. The risk of mastitis was determined by logistic regression. Monthly somatic cell counts (SCC) were analyzed using repeated measures analysis of variance. Finally, culling rate was assessed by a Kaplan-Meier survival analysis. No significant differences were observed in milk production (p=0.07), averaging 42.3 Lt/day for Boostin®, and 42.8 Lt/day for Lactotropina®. No significant differences on calving-to-conception interval were recorded during the first 180 days of lactation (p=0.19), showing a median of 101 days in Lactotropina® group and 90 days in cows treated with Boostin®. Conception rate at first insemination was 40% in Boostin® treated cows and 32.8% Lactotropina® in treated cows (p=0.16). No significant differences were observed in the risk of pregnancy at first insemination (p>0.05). Cows treated with Lactotropina® have a higher incidence of clinical mastitis (33.5%) compared to Boostin® treated cows (21.1%) (p=0.01) and showed twice as likely to develop mastitis during the treatment period compared to cows treated with Boostin® (p=0.007). Regarding SCC in milk, no significant differences were observed, averaging Lactotropina® and Boostin® groups scores of 2.43±0.08 and 2.4±0.07, respectively (p=0.9). Finally, treatment have no effect on culling rate (p=0.78). In conclusion, there are no substantial differences between hormone preparations regarding milk production, udder health and fertility in high-producing Holstein cows.

Made available in DSpace on 2016-07-18T17:53:16Z (GMT). No. of bitstreams: 1 ronaldo sena e silva.pdf: 758805 bytes, checksum: 50ddd870dfedb208e155053c6ec67166 (MD5) Previous issue date: 2015-09-24 / The aim of this study was to verify the use of growth hormone (GH), with or without resisted exercise, the estrous cycle, the dosage of the estradiol and progesterone and Wistar rats endometrium thickness. The rats were divided into four groups (n = 10): CT (Control); Ex (resisted exercise - water jumps with 50% of body weight); GH (0,2UI / kg administered GH); and ExGH (GH and Ex groups combined treatment). The estrous cycle phase of rats were determined by vaginal cytology, daily for 29 days. The rats plasma was used for hormone dosage and the endometrium thicknesses were evaluated by histology. We used the Shapiro-Wilk normality presupposition. For samples that was parametric, ANOVA was used with Tukey, for no parametric samples, Kruskal-Wallis with Student-Newman-Keuls test was used (p<0.05). There are a greater reproductive cycles number in CT than in other groups during the 29 days period (p>0.05), no difference were found between the hormones dosage groups neither endometrial thickness. Therefore, it is concluded that GH and resisted exercises both combined affect females reproductive cycle, they reduced the number of cycles of rats but they do not change the estradiol and progesterone concentrations, neither endometrial thickness. / O objetivo deste estudo foi verificar o uso do hormônio do crescimento (GH), associado ou não ao exercício resistido, no ciclo estral, na dosagem do estradiol e progesterona e na espessura do endométrio de ratas Wistar. As ratas foram divididas em 4 grupos (n=10): CT (controle); Ex (exercício resistido - saltos em água com 50% do peso corporal); GH (0,2UI/Kg de GH administrado); e ExGH (tratamento combinado dos grupos GH e Ex). A fase do ciclo estral foi determinada por citologias vaginais nas ratas, diariamente, durante 29 dias. Foi realizado dosagem hormonal nas ratas e as espessuras dos endométrios foram avaliadas por histologia. Utilizou-se o pressuposto de normalidade de Shapiro-Wilk. Para as amostras paramétricas, utilizou-se ANOVA e Tukey e para não paramétricas Kruskal-Wallis e Student-Newman-Keuls (p<0,05). Houve maior número de ciclos reprodutivos no CT que nos demais grupos no período de 29 dias (p<0,05), nenhuma diferença foi encontrada entre os grupos na dosagem hormonal ou na espessura de endométrio. Portanto, conclui-se que o GH, o exercício resistido e os dois combinados interferem na ciclicidade reprodutiva das fêmeas, reduzindo o número de ciclos das ratas, sem alterar a concentração de estradiol e progesterona ou a espessura do endométrio.