Evaluación de injuria cardíaca en novillos a distintas dosis de monensina sódica dietaría medida a través de creatina kinasa miocárdica / Evaluation of cardiac insult in steers with different dietary sodic monensin concentration measured thought mioc

The aim of this study was to evaluate a possible myocardial  damage on feedlot steers caused by high doses of monensin (MN). A commercial kit was used to determinate the concentration of myocardial creatine kinase (CK-MB). Four groups of animals were conformed according to the diet MN concentration. G1: Control, without MN, G2: MN Tag dose, 1 mg kg body weight (BW) -1 , G3: MN 5 mg kg BW -1 and G4: MN 10 mg kg BW -1 The cattle were housed in pens for eleven days. Venous blood  samples were taken at 0, 48, 120, 168 and 264 h. Serum CK-MB  concentration was analyzed using descriptive and comparative  statistics analysis of variance (ANOVA) with a significance level  of P<0,05. No CK-MB mean concentration above cut-off level (90  U/l) was recorded throughout the assay for any treatment. The  G1 mean throughout the assay was 47,84 ± 21,28 U/l showing  statistical differences (P<0.05) from 120 h up to the end of the  study, as compared to the others groups. Means of G2, G3 and G4  were 37,31 ± 37,31; 34,09 ± 12,96; 34,62 ± 19,90 U/l, respect tively. This study could not determine heart damage caused by  MN, measured through a commercial kit, despite the widespread  time assessed. The control group had higher CK-MB mean concentration than all others groups, from 48 h until the end of the  study. This result could indicate a possible beneficial and regulatory effect on digestive microflora by the MN antibiotic, resulting in less exposure to bacterial endotoxinsEl objetivo del presente trabajo fue evaluar un posible daño de  miocardio en novillos en feedlot ante la administración continua  de dosis elevadas de monensina (MN) en la dieta, utilizando para  ello el kit comercial que determina la concentración de creatinaquinasa miocárdica (CK-MB). Se conformaron cuatro grupos de  acuerdo a la concentración de MN en la dieta, G1: Control, sin  monensina, G2: dosis marbete, MN 1 mg kg PV -1 , G3: MN 5 mg  kg PV -1 y G4: MN 10 mg kg PV -1 . El ganado fue mantenido en los  corrales por un periodo de 11 días con muestreos de sangre por  venopunción yugular a la hora 0, 48, 120, 168 y 264 de iniciada  la prueba. Las concentraciones séricas de CK-MB fueron analizadas mediante estadística descriptiva y comparativa usando  un análisis de variancia (ANOVA) con un nivel de significancia  de P<0,05. No se registraron concentraciones de CK-MB pro medio por encima del punto de corte (90 U/l) a lo largo de la  prueba para ninguno de los tratamientos propuestos. La media  aritmética evaluada a lo largo de toda la prueba para el grupo  G1 fue de 47,84±21,28 U/l, mostrando diferencias estadísticas  (P<0,05) a partir de las 120 h de iniciada la prueba en relación  a los demás grupos. La media para los grupos G2, G3 y G4 fue de  37,31±17,00; 34,09±12,96 y 34,62±19,90 U/l, respectivamente.  No se pudo determinar la participación de MN como causante  de lesión cardíaca medido a través del kit comercial a pesar del  prolongado período de tiempo evaluado. Considerando que el  grupo control presentó concentraciones promedio más elevadas a partir de las 48 hs y hasta la finalización de la prueba en rela ción a los tres grupos que contenían MN, se debería considerar un posible efecto beneficioso y regulador de la microflora del  tracto digestivo por parte de dicho antibiótico, generando una  menor exposición a endotoxinas bacterianas DOI:http://dx.doi.org/10.19137/cienvet2016-181

Comparison between the 5-day cosynch and 7-day estradiol-based protocols for synchronization of ovulation and timed artificial insemination in suckled BOS taurus BEEF cows

The objective was to compare pregnancy per AI and follicular dynamic in suckled Bos taurus beef cows treated with either a 7-day progesterone + estradiol-based protocol or a 5-day progesterone CoSynch protocol for timed artificial insemination (TAI) during four breeding seasons. We hypothesized that estrous cycle status, days postpartum (DPP), fat depth and plasma progesterone concentration differentially modify the effect of treatments. Every year, 9 days before initiation of each breeding season, cows were randomly assigned to one of two groups. Cows in the 7-d P + E group (n = 428) received a progesterone intravaginal device (DIB) and estradiol benzoate on Day −9. On Day −2 the device was removed, and cows received cloprostenol and estradiol cypionate. Forty-eight hours later (Day 0) cows received TAI. Cows in the 5-d P + CoS group (n = 428) received a DIB, and GnRH on Day −8. On Day −3, the device was removed, and cows received cloprostenol. A second dose of cloprostenol was given on Day −2. Cows received GnRH and TAI 72 h after device removal (Day 0). On Day −9, estrous cycle status was determined. In a subset of cows (n = 79) the size of the dominant follicle was determined between Days −2 and 0. In another subset of cows (n = 340), DPP, fat depth (mm) and plasma progesterone concentration (ng/mL) were evaluated on Day −9. Pregnancy per AI was determined 30 d after TAI. Pregnancy per AI was greater for cows in the 5-d P + CoS group than for cows in the 7-d P + E group (50.9% vs. 41.3%, P = 0.01) and was also greater in cyclic than in anestrus cows (54.3% vs. 33.2%, P < 0.0001). There was also a significant effect of breeding season (P = 0.0002) and sire (P = 0.03), and an interaction between treatment group and breeding season (P = 0.03). The dominant follicle was larger (P < 0.0001) in cows in the 5-d P + CoS group than the 7-d P + E group (10.7 ± 0.29 mm vs. 9.0 ± 0.28 mm). Pregnancy per AI was greater in cows with ≥55 DPP (47.0% vs. 29.6%, P = 0.001), fat depth ≥0.50 mm (44.7% vs. 29.7%), and with plasma progesterone concentration ≥1 ng/mL (47.2% vs. 28.7%, P = 0.01). In cows with plasma progesterone ≥1 ng/mL on Day −9, pregnancy per AI was greater in the 5-d P + CoS group (60.5%) than in the 7-d P + E group (34.9%), but there was no difference between treatment groups in cows with plasma progesterone < 1 ng/mL (P = 0.07). In conclusion, the 5-d P + CoS protocol resulted in greater size of the dominant follicle and pregnancy per AI in suckled Bos taurus beef cows subjected to TAI.Fil: Bilbao, María Guillermina. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; ArgentinaFil: Zapata, Luis Oscar. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Romero Harry, H.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria Anguil; ArgentinaFil: Perez Wallace, S.. Zoetis SRL; ArgentinaFil: Farcey, Maria Florencia. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Gelid, Lucas Fernando. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria Anguil; ArgentinaFil: Palomares, R. A.. University of Georgia. College of Veterinary Medicine; Estados UnidosFil: Ferrer, M. S.. University of Georgia. College of Veterinary Medicine; Estados UnidosFil: Bartolome, Julian. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentin

Comparison between the 5-day cosynch and 7-day estradiol-based protocols for synchronization of ovulation and timed artificial insemination in suckled BOS taurus BEEF cows

The objective was to compare pregnancy per AI and follicular dynamic in suckled Bos taurus beef cows treated with either a 7-day progesterone + estradiol-based protocol or a 5-day progesterone CoSynch protocol for timed artificial insemination (TAI) during four breeding seasons. We hypothesized that estrous cycle status, days postpartum (DPP), fat depth and plasma progesterone concentration differentially modify the effect of treatments. Every year, 9 days before initiation of each breeding season, cows were randomly assigned to one of two groups. Cows in the 7-d P + E group (n = 428) received a progesterone intravaginal device (DIB) and estradiol benzoate on Day −9. On Day −2 the device was removed, and cows received cloprostenol and estradiol cypionate. Forty-eight hours later (Day 0) cows received TAI. Cows in the 5-d P + CoS group (n = 428) received a DIB, and GnRH on Day −8. On Day −3, the device was removed, and cows received cloprostenol. A second dose of cloprostenol was given on Day −2. Cows received GnRH and TAI 72 h after device removal (Day 0). On Day −9, estrous cycle status was determined. In a subset of cows (n = 79) the size of the dominant follicle was determined between Days −2 and 0. In another subset of cows (n = 340), DPP, fat depth (mm) and plasma progesterone concentration (ng/mL) were evaluated on Day −9. Pregnancy per AI was determined 30 d after TAI. Pregnancy per AI was greater for cows in the 5-d P + CoS group than for cows in the 7-d P + E group (50.9% vs. 41.3%, P = 0.01) and was also greater in cyclic than in anestrus cows (54.3% vs. 33.2%, P < 0.0001). There was also a significant effect of breeding season (P = 0.0002) and sire (P = 0.03), and an interaction between treatment group and breeding season (P = 0.03). The dominant follicle was larger (P < 0.0001) in cows in the 5-d P + CoS group than the 7-d P + E group (10.7 ± 0.29 mm vs. 9.0 ± 0.28 mm). Pregnancy per AI was greater in cows with ≥55 DPP (47.0% vs. 29.6%, P = 0.001), fat depth ≥0.50 mm (44.7% vs. 29.7%), and with plasma progesterone concentration ≥1 ng/mL (47.2% vs. 28.7%, P = 0.01). In cows with plasma progesterone ≥1 ng/mL on Day −9, pregnancy per AI was greater in the 5-d P + CoS group (60.5%) than in the 7-d P + E group (34.9%), but there was no difference between treatment groups in cows with plasma progesterone < 1 ng/mL (P = 0.07). In conclusion, the 5-d P + CoS protocol resulted in greater size of the dominant follicle and pregnancy per AI in suckled Bos taurus beef cows subjected to TAI.Estación Experimental Agropecuaria AnguilFil: Bilbao, Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Zapata, Luis. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Romero Harry, Hernan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Wallace Perez, Santiago. Zoetis SRL; ArgentinaFil: Farcey, Florencia. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Gelid, Lucas. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Palomares, Roberto. University of Georgia. College of Veterinary Medicine. Department of Large Animal Medicine and Population Health; Estados UnidosFil: Ferrer, María. University of Georgia. College of Veterinary Medicine. Department of Large Animal Medicine and Population Health; Estados UnidosFil: Bartolome, Julian. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentin