Productivity of Pelibuey and Blackbelly ewes in Mexico under extensive management

Segura, J. C.; Sarmiento, L; Rojas, O. J.

doi:10.1016/0921-4488(95)00814-4

Cited by 21 publications

(19 citation statements)

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“…In this latest study ewes in their first and second lambing showed a similar WLB, but lower than that of ewes with more than two lambings. In a previous study done with Pelibuey and Blackbelly ewes indicates that WLB was similar during the first three lambings, but in subsequent lambings it is increased (Segura et al 1996). Differences among studies probably are associated with the type of nutritional management applied to ewes during pregnancy and the degree of precision to establish the number of lambing of the ewes.…”

Section: Resultsmentioning

confidence: 99%

A note on the changes in the preweaning growth of Pelibuey lambs

Oliva-Hernández

García-Osorio

2016

Arch. med. vet.

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Section: Resultsmentioning

confidence: 99%

A note on the changes in the preweaning growth of Pelibuey lambs

Oliva-Hernández

García-Osorio

2016

Arch. med. vet.

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“…La edad en la que la concentración de LH empieza a aumentar parece estar relacionada con la precocidad y prolificidad de la raza, ya que el aumento de LH se observa más temprano en razas más precoces (1) y más prolíficas (5,19) . Por lo tanto, la falta de diferencias entre genotipos para cualquiera de las variables de los perfiles de LH y T fue inesperada, ya que varios autores han encontrado que Blackbelly es una raza más precoz y más prolífica que Pelibuey (7,8,10,12) . Es posible que las diferencias entre sexos en los mecanismos endocrinos que conducen a la pubertad (20) hayan ocultado diferencias sutiles entre los machos de estas razas.…”

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Section: Introductionunclassified

“…Barbados Blackbelly (en adelante simplemente Blackbelly) y Pelibuey son razas de pelo importantes (Ovis aries), desarrolladas en latitudes tropicales y, por lo tanto, bien adaptadas a estas condiciones. Blackbelly es considerada una de las razas de pelo más prolíficas (6) ; más prolífica que la Pelibuey (7,8) , pero el tamaño de camada en esta última es mayor que en otras razas tropicales (9) ; por otro lado, hay controversia en cuanto a si Blackbelly es más precoz que Pelibuey (10)(11)(12)(13) .En los corderos Blackbelly se observa un aumento temprano de las concentraciones séricas de la hormona luteinizante (LH) a las 6 semanas de edad, y aumento de la testosterona (T) en las semanas 12 y 21 (14) ; sin embargo, esta información se basó en muestras individuales; debido a la naturaleza pulsátil de la secreción de LH y T, es necesario obtener muestras con mayor frecuencia para caracterizar con precisión los perfiles hormonales y la sensibilidad del eje hipófisis-testículo. Adicionalmente, al parecer no se ha hecho una comparación directa del desarrollo endocrino entre corderos Blackbelly y Pelibuey; por lo tanto, el objetivo del estudio fue caracterizar el desarrollo del eje reproductivo endocrino en corderos Blackbelly, Pelibuey y Blackbelly x Pelibuey (cruzas).…”

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“…Barbados Blackbelly (hereafter just Blackbelly) and Pelibuey are important hair breeds (Ovis aries) developed in tropical latitudes and, therefore, well adapted to tropical conditions. Blackbelly is considered one of the most prolific hair breeds (6) ; previous studies have shown that Blackbelly ewes are more prolific than Pelibuey ewes (7,8) , but litter size in Pelibuey is greater than in other breeds raised in the tropics (9) . Some controversy still exists as to whether Blackbelly is more precocious than Pelibuey (10)(11)(12)(13) .…”

Section: Introductionmentioning

confidence: 99%

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Development of the endocrine reproductive axis in hair breed ram lambs

Montiel-Olguín

Ávila

Amezcua

et al. 2016

Rev. Mex. Cienc. Pecu.

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RESUMENLos objetivos fueron caracterizar los perfiles de LH y testosterona (T) y la respuesta a GnRH en corderos de pelo. Estudio 1: se utilizaron corderos Blackbelly (n=4), Pelibuey (n=5), Blackbelly x Pelibuey (Cruzas; n=8). A las 2, 4, 8, 12, 16, 20 y 24 semanas de edad, se obtuvieron muestras de sangre cada 15 min durante 6 h, para caracterizar los perfiles de LH y T. No hubo diferencia entre genotipos a ninguna edad, para ninguna variable de LH y T (P>0.05); el efecto de la edad fue significativo (P<0.05): la concentración promedio de LH fue menor en la semana 2 (P<0.05), alcanzó el valor más alto en la 12, y disminuyó en la 16 (P<0.05). La concentración promedio de T aumentó constantemente entre 2 y 24 semanas (P<0.05). Estudio 2: se utilizaron corderos Blackbelly (n=4), Pelibuey (n=4), Cruzas (n=4). A las mismas edades, los corderos se desafiaron con GnRH (3, 9, 27 ng•kg -1 peso) y se obtuvieron muestras de sangre entre -15 y 180 min. En las semanas 8 y 12, la respuesta de LH fue mayor en los corderos Pelibuey, en comparación con Blackbelly. La respuesta de T tendió a ser diferente entre genotipos (P<0.10), con Blackbelly mostrando la menor respuesta. En conclusión, el desarrollo de los perfiles de LH y T no fue diferente entre genotipos, pero los corderos Pelibuey presentaron mayor capacidad de respuesta a GnRH en las semanas 8 y 12; es necesario determinar si estas diferencias tienen implicaciones sobre la capacidad reproductiva de los animales adultos.PALABRAS CLAVE: Blackbelly, Pelibuey, LH, Testosterona, Desarrollo sexual. ABSTRACTThe objectives were to characterize the profiles of LH and testosterone (T) and the response to GnRH administration in hair ram lambs. Study 1: seventeen lambs were used: Blackbelly (n=4), Pelibuey (n=5), Blackbelly x Pelibuey (Crossbred; n=8). At 2, 4, 8, 12, 16, 20 and 24 wk of age, blood samples were collected every 15 min for 6 h, to characterize LH and T profiles. There was no significant difference between genotypes at any age, for any variable of LH and T profiles (P>0.05). The effect of age was significant (P<0.05): mean LH concentration was lower on wk 2 (P<0.05), achieved the highest value on wk 12, and decreased on wk 16 (P<0.05). Mean T concentration increased steadily between wk 2 and 24 (P<0.05). Study 2: twelve lambs were used: Blackbelly (n=4), Pelibuey (n=4), Crossbred (n=4). At the same ages, lambs were challenged with GnRH (3, 9, 27 ng•kg -1 BW) and blood samples were obtained between -15 and 180 min from GnRH administration. On wk 8 and 12, LH response to GnRH was greater in Pelibuey, as compared with Blackbelly. Testosterone response tended to be different between genotypes (P<0.10), with Blackbelly showing the smallest response. In conclusion, the sexual endocrine development, as evaluated by the non-stimulated LH and T profiles, was not different among genotypes; however, Pelibuey elicited the greatest responsiveness to GnRH administration at 8 and 12 wk of age. Whether or not such differences have implications on the reproductive capacity of the adul...

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Effects of genetic and environmental factors on pre-weaning and post-weaning growth in West African crossbred sheep

Benyi

Norris

Karbo

et al. 2006

Trop Anim Health Prod

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Effects of genetic and environmental factors on pre-weaning and post-weaning growth were studied in West African crossbred sheep. Effects of lamb genotype (7/8 Sahelian-1/8 Djallonké, 3/4 Sahelian-1/4 Djallonké and 1/2 Sahelian-1/2 Djallonké; hereafter denoted 7/8Sa, 3/4Sa and 1/2Sa, respectively), parity, type of birth, sex of lamb and year-season of lambing on birth weight, weaning weight, 8-month weight and pre- and post-weaning growth rates were determined. At birth 7/8Sa and 3/4Sa lambs were heavier (p < 0.01) than 1/2Sa lambs. Lambs born to first-parity ewes were lighter (p < 0.01) at birth than lambs of older ewes. At weaning and 8 months of age, lambs born to fourth-parity ewes were heavier (p < 0.05) than those born to ewes of the other parities. Parity did not have any significant effects on pre-weaning growth rate. Lambs born in the rainy season of 2001 were significantly heavier at birth and at 8 months of age than those born in the dry season of 2001/02, but there was no difference between the two groups at weaning. Pre-weaning growth rate was significantly faster in lambs born in the dry season of 2001/02 but the reverse was true for post-weaning growth rate.

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Productivity of Pelibuey and Blackbelly ewes in Mexico under extensive management

Cited by 21 publications

References 4 publications

A note on the changes in the preweaning growth of Pelibuey lambs

A note on the changes in the preweaning growth of Pelibuey lambs

Development of the endocrine reproductive axis in hair breed ram lambs

Effects of genetic and environmental factors on pre-weaning and post-weaning growth in West African crossbred sheep

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