Efficiency of two timed artificial insemination protocols in Murrah buffaloes managed under a semi-intensive system in the tropics.

The objective of the study was to determine the efficiency of ovsynch (OV) versus presynch-ovsynch (P-OV) protocol for synchronization of ovulation and timed artificial insemination (TAI) in female buffaloes. The OV group (n = 40) received gonadotrophin-releasing hormone (GnRH) on day 0 (random day of the estrous cycle), prostaglandin PGF2α on day 7 and a second GnRH administration on day 9 followed by a single artificial insemination (AI) 16-20 h later. The P-OV group (n = 40) received two PGF2α injections 14 days apart, with the second injection administered 14 days before starting the OV protocol. Progesterone (P(4)) was measured at the time of PGF2α administration (within the OV protocol) and AI. Neither ovulation rate ((24 h after TAI) OV 90%-36/40 vs. P-OV 85%-34/40) nor pregnancy rates ((day 60 after TAI) OV 35%-14/40 vs. P-OV 45%-18/40) differed between the two protocols. Pregnant buffaloes had lower concentrations of P(4) at AI compared with non-pregnant animals in the OV group (0.7 +/- 0.1 vs. 1.1 +/- 0.1 ng/ml); but in the P-OV group, differences did not reach statistical significance (0.8 +/- 0.1 vs. 1.0 +/- 0.1 ng/ml). This apparent trend reached statistical significance when the analysis was carried out in animals from both protocols (0.7 +/- 0.1 (pregnant) vs. 1.1 +/- 0.1 (non-pregnant) ng/ml). In conclusion, both protocols synchronize ovulation effectively with no significant differences in conception rates. High concentrations of P(4) at AI seem to be detrimental for the establishment of pregnancy in lactating buffalo cows.

Valoración del Estrés en Toros Brasileros y Venezolanos Mediante la Evaluación de las Concentraciones de Cortisol y el Recuento Leucocitario / Assessment of stress in Brazilian and Venezuelan Bulls by the evaluation of cortisol concentrations and leucocytes count

A fin de valorar el estrés en toros, se seleccionaron al azar de un matadero de la región centro occidental de Venezuela, un total de 40 toros mestizos Brahman (16 de Brasil y 24 de Venezuela). Se tomaron muestras de sangre para realizar el recuento leucocitario. Igualmente, se determinó la concentración de cortisol mediante la técnica del ELISA competitivo. Los datos fueron analizados usando la prueba no paramétrica U de Mann Whitney. Los resultados del estudio muestran que hubo un incremento no estadísticamente significativo en el recuento diferencial de neutrófilos (53,13% y 43,19%) en toros venezolanos y brasileños, respectivamente. Al mismo tiempo, los toros venezolanos arrojaron un valor de cortisol que fue superior (59,44 ng/dL) y estadísticamente significativo (P≤0,05), cuando se comparó con el de los toros brasileños (40,50 ng/dL). Además, se produjo una disminución no significativa, en el recuento diferencial de eosinófilos (eosinopenia) en ambos grupos, con un promedio de 0,78%. Por otra parte, el recuento diferencial de linfocitos solamente disminuyó significativamente (P≤0,05), en los toros venezolanos (43,25%), mientras que el porcentaje correspondiente a linfocitos de los toros brasileños, se ubicó dentro de los valores normales para la especie (56,19%). Se concluye que los valores elevados de cortisol y neutrófilos, así como también, la eosinopenia y linfopenia encontradas en los toros venezolanos, sugieren un leucograma de estrés, compatible con la conducta nerviosa observada en esos animales. El estrés en los toros brasileños sólo se asoció con una alteración (aumento) de las concentraciones de cortisol y en los valores de eosinófilos. La procedencia y/o tiempo de transporte afectó por igual las concentraciones de cortisol, especialmente en los toros venezolanos. Los cambios sociales observados en los toros venezolanos y brasileños, sugieren la presencia de estrés agudo en los primeros y de estrés crónico en los segundos.

A study was conducted to assess stress in bulls. A total of 40 crossbred Brahman bulls (16 from Brazil and 24 from Venezuela) were selected at random from a slaughterhouse in the Midwestern region of Venezuela. Blood samples were taken for leukocytes count. Also, the cortisol concentration was determined by competitive ELISA technique. Data were analyzed using the nonparametric Mann Whitney U test. The results of the present study show that there was a non-statistically significant increase in neutrophil count (53.13% and 43.19%) in Venezuelan and Brazilian bulls, respectively. At the same time, Venezuelan bulls showed a higher (59.44 ng / dL) cortisol value that was statistically significant (P≤ 0.05), when compared with the Brazilian bulls (40.50 ng/dL). There was also a non- significant decrease in the differential eosinophil count (eosinopenia) in both groups, with an average of 0.78%. On the other hand, the lymphocytes differential count significantly diminished (P≤0.05) in Venezuelan bulls (43.25%) only, while in Brazilian bulls, the percentage corresponding to lymphocytes, was within the normal range for the species (56.19%). It is concluded that that the elevated cortisol and neutrophils levels, as well as the eosinopenia and lymphopenia found in Venezuelan bulls, suggest a stress leukogram, compatible with the nervous behavior observed in those animals. Stress in Brazilian bulls was only associated with an alteration (increase) in cortisol concentrations and in eosinophil values. Both the origin and/or transport time equally affected cortisol concentrations, especially in the Venezuelan bulls. Social changes observed in the Venezuelan and Brazilian bulls, suggest the presence of acute stress in the first and of chronic stress in the latter.

Perfil sérico de las Hormonas Luteinizante, Folículo Estimulante y 17β-Estradiol en cerdas Landrace x Large White durante el pre-parto, lactancia y posdestete / Profile of Luteinizing Hormone, Follicle-stimulating Hormone and 17β-Estradiol during the pre-farrowing, lactation and weaning of cross-bred Landrace x Large White sows

Uno de los índices de productividad de la cerda es el número de partos al año, dependiendo éste de la duración de la gestación, lactancia e intervalo destete-preñez. El objetivo de este estudio fue determinar el perfil endocrino reproductivo en cerdas mestizas F1 de la raza Landrace x Large White, durante el preparto, durante la lactancia y hasta el destete, mediante la concentración sérica de LH y FSH, y del 17β-Estradiol (E2). Se seleccionaron por muestreo aleatorio simple, 15 cerdas gestantes mestizas Landrace x Large White de una explotación porcina, ubicada en el estado Yaracuy. Se les extrajo mediante punción de la vena yugular, una muestra de sangre 7 d antes del parto, 1, 7, 14 y 21 d posparto y 1 y 3 d posdestete. Se determinó la concentración sérica de las hormonas mediante la prueba de ELISA. El análisis estadístico se realizó utilizando el programa SPSS versión 10,0 para Windows, aplicándose una prueba descriptiva, seguida de comparación múltiple (P<0,05). La concentración de LH aumentó durante la lactancia hasta un valor máximo el tercer día posdestete (7,40±0,97 mU/mL), debido a la recuperación de la ciclicidad ovárica. Los niveles de FSH fueron menores durante el posparto, en comparación al preparto (6,30±1,10 mU/mL) mientras que la concentración máxima de E2 se observó al d 3 posdestete (2139,67±125,2 µg/mL), simultánea a la conducta propia del estro. En las cerdas evaluadas el perfil hormonal respondió a un coordinado y sensible balance de regulación endocrina, que permitió que ocurriera el parto, la lactancia y el reinicio precoz de la actividad ovárica, al d 3 durante el destete.

One of the indexes of productivity of the sow is the number of suckling pigs along the year and depends on the length of gestation, lactation and weaning-pregnancy interval. The objective of this study was to determine the profile of LH, FSH and 17β-estradiol during the pre-farrowing, lactation and post-weaning periods, of 15 pregnant cross-bred sows (Landrace x Large White), belonging to a farm in Yaracuy State. By punction of the jugular vein a blood sample was drawn on d 7 before the farrowing, on d 1, 7, 14 and 21 post-farrowing on d 1 and 3 post-weaning. Hormone quantification was performed using an ELISA test. The statistical analysis was made by the program SPSS version 10.0 for Windows. A descriptive test followed by multiple comparison, was applied (P<0.05). LH increased during the lactation until a maximum value on d 3 post-weaning (7.40±0.97 mU/mL). FSH levels were lower (P>0.001) during the post-farrowing period in comparison to the pre-farrowing period (6.30±1.10 mU/mL), whereas at weaning the levels increased. The maximum concentration of the E2 was observed on the third day post-weaning (2139.67±125.2 µg/mL) and it was simultaneous with the proper estrous behavior. In the cross-bred sow the hormonal profile is a fine balance of endocrine regulation that allows the farrowing, the lactation and the recovery of the cyclic activity of the ovary, during the early post-weaning period.