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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
20/10/2016 |
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Data da última atualização: |
20/10/2016 |
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Autoria: |
KIRKWOOD, R. N.; THACKER, P. A.; RORCHINSKI, R. S.; GONZALEZ, A.; LAARVELD, B. |
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Título: |
The influence of monensin and lasalocid on the breeding performance of ewes and the endocrine status of ewe lambs. |
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Ano de publicação: |
1991 |
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Fonte/Imprenta: |
Canadian Journal of Animal Science, v. 71, n. 4, p. 1073-1077, Dec. 1991. |
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DOI: |
10.4141/cjas91-129 |
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Idioma: |
Inglês |
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Conteúdo: |
Two experiments were performed, in December and August, to determine the effects of dietary ionophores on the breeding performance of ewes and the endocrine status of ewe lambs. Experiment 1 employed 127 mixed-parity ewes fed diets containing 33 ppm monensin (M, n = 43), 45 ppm lasalocid (L, n = 43) or no additive (C, n=41). Estrus was synchronized with progesterone sponges and the ewes were allowed to breed. The proportion of ewes conceiving at their first estrus was higher (P < 0.05) for control ewes than for L ewes (70.7 vs. 51.2%) M ewes being intermediate (53.5%). Litter size of ewes conceiving at first estrus was not affected by treatment. Experiment 2 employed 57 ewe lambs allocated in a 3×2 factorial arrangement to be fed rations containing 33 ppm M, 45 ppm L or no additive for 26 d and to receive, or not, an injection of 50 g GnRH at 21 d. For lambs receiving GnRH, blood samples were taken every 15 min for 2 h from 30 min pre-injection. At 72 h after GnRH injection, all lambs received an injection of 50 g estradiol 17. Further blood samples were taken from all lambs at 4-h intervals for 48 h. Serum LH and FSH concentrations increased from pre-injection means of 1.6 ± 0.2 and 7.8 ± 1.2 ng mL -1 to 20.9 ± 1.9 and 13.4 ± 1.4 ng mL -1, respectively, by 1 min after GnRH injection. These responses were not affected by either ionophore. The estradiol-induced LH surge height was reduced (P < 0.01) in lambs that had received GnRH. These data indicate that at the dietary inclusion levels employed, ionophores may be contra-indicated in the breeding ration. MenosTwo experiments were performed, in December and August, to determine the effects of dietary ionophores on the breeding performance of ewes and the endocrine status of ewe lambs. Experiment 1 employed 127 mixed-parity ewes fed diets containing 33 ppm monensin (M, n = 43), 45 ppm lasalocid (L, n = 43) or no additive (C, n=41). Estrus was synchronized with progesterone sponges and the ewes were allowed to breed. The proportion of ewes conceiving at their first estrus was higher (P < 0.05) for control ewes than for L ewes (70.7 vs. 51.2%) M ewes being intermediate (53.5%). Litter size of ewes conceiving at first estrus was not affected by treatment. Experiment 2 employed 57 ewe lambs allocated in a 3×2 factorial arrangement to be fed rations containing 33 ppm M, 45 ppm L or no additive for 26 d and to receive, or not, an injection of 50 g GnRH at 21 d. For lambs receiving GnRH, blood samples were taken every 15 min for 2 h from 30 min pre-injection. At 72 h after GnRH injection, all lambs received an injection of 50 g estradiol 17. Further blood samples were taken from all lambs at 4-h intervals for 48 h. Serum LH and FSH concentrations increased from pre-injection means of 1.6 ± 0.2 and 7.8 ± 1.2 ng mL -1 to 20.9 ± 1.9 and 13.4 ± 1.4 ng mL -1, respectively, by 1 min after GnRH injection. These responses were not affected by either ionophore. The estradiol-induced LH surge height was reduced (P < 0.01) in lambs that had received GnRH. These data indicate that at the dietary incl... Mostrar Tudo |
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Palavras-Chave: |
GnRH; Hormonal control; Ionóforo; LH; Monensina sódica. |
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Thesagro: |
Alimento concentrado; Alimento para animal; Controle hormonal; Eficiência reprodutiva; Hormônio; Ovelha; Ovino; Reprodução animal. |
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Thesaurus Nal: |
Animal feeding; Concentrates; Ewes; Ionophores; Monensin; Reproduction; Sheep. |
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Categoria do assunto: |
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Marc: |
LEADER 02722nam a2200409 a 4500
001 2055040
005 2016-10-20
008 1991 bl uuuu u0uu1 u #d
024 7 $a10.4141/cjas91-129$2DOI
100 1 $aKIRKWOOD, R. N.
245 $aThe influence of monensin and lasalocid on the breeding performance of ewes and the endocrine status of ewe lambs.
260 $aCanadian Journal of Animal Science, v. 71, n. 4, p. 1073-1077, Dec. 1991.$c1991
520 $aTwo experiments were performed, in December and August, to determine the effects of dietary ionophores on the breeding performance of ewes and the endocrine status of ewe lambs. Experiment 1 employed 127 mixed-parity ewes fed diets containing 33 ppm monensin (M, n = 43), 45 ppm lasalocid (L, n = 43) or no additive (C, n=41). Estrus was synchronized with progesterone sponges and the ewes were allowed to breed. The proportion of ewes conceiving at their first estrus was higher (P < 0.05) for control ewes than for L ewes (70.7 vs. 51.2%) M ewes being intermediate (53.5%). Litter size of ewes conceiving at first estrus was not affected by treatment. Experiment 2 employed 57 ewe lambs allocated in a 3×2 factorial arrangement to be fed rations containing 33 ppm M, 45 ppm L or no additive for 26 d and to receive, or not, an injection of 50 g GnRH at 21 d. For lambs receiving GnRH, blood samples were taken every 15 min for 2 h from 30 min pre-injection. At 72 h after GnRH injection, all lambs received an injection of 50 g estradiol 17. Further blood samples were taken from all lambs at 4-h intervals for 48 h. Serum LH and FSH concentrations increased from pre-injection means of 1.6 ± 0.2 and 7.8 ± 1.2 ng mL -1 to 20.9 ± 1.9 and 13.4 ± 1.4 ng mL -1, respectively, by 1 min after GnRH injection. These responses were not affected by either ionophore. The estradiol-induced LH surge height was reduced (P < 0.01) in lambs that had received GnRH. These data indicate that at the dietary inclusion levels employed, ionophores may be contra-indicated in the breeding ration.
650 $aAnimal feeding
650 $aConcentrates
650 $aEwes
650 $aIonophores
650 $aMonensin
650 $aReproduction
650 $aSheep
650 $aAlimento concentrado
650 $aAlimento para animal
650 $aControle hormonal
650 $aEficiência reprodutiva
650 $aHormônio
650 $aOvelha
650 $aOvino
650 $aReprodução animal
653 $aGnRH
653 $aHormonal control
653 $aIonóforo
653 $aLH
653 $aMonensina sódica
700 1 $aTHACKER, P. A.
700 1 $aRORCHINSKI, R. S.
700 1 $aGONZALEZ, A.
700 1 $aLAARVELD, B.
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Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
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