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Biblioteca (s) : |
INIA Tacuarembó. |
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Fecha : |
04/11/2015 |
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Actualizado : |
10/11/2015 |
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Autor : |
THOMSON, B.C.; MUIR, P.D.; SMITH, N.B. |
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Afiliación : |
B.C. THOMSON; P. D. MUIR; N.B. SMITH. |
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Título : |
Litter size, lamb survival, birth and twelve week weight in lambs born to cross-bred ewes. |
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Fecha de publicación : |
2004 |
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Fuente / Imprenta : |
En: Proceedings of the New Zealand Grassland Association, 66., 2004. |
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Páginas : |
p. 233-237 |
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Idioma : |
Español |
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Contenido : |
This study looked at ewe effects on the number of lambs reared (litter size and mortality) and lamb 12 week weight (birth weight and growth rate). Over six years, data was collected on 5571 lambs born to around 3390 Romney (R), Finn cross Romney (F x R), East Friesian cross Romney (EF x R) and Poll Dorset cross Romney (PD x R) ewes. Ewe live weights were recorded pre-lambing and 12 weeks post-lambing. Lambs were weighed at birth and 12 weeks post-lambing. Ewe effects played a
significant role in affecting the productivity of the system and many effects were cumulative. Over six years, the lambing percentage (lambs born/ewes lambing) was 165 %. Two tooth ewes had lower lambing percentages than the mixed age ewes (155 vs 170 %). Lambing percentages were 186 % for F x R, 171 % for the EF x R,
155 % for the PD x R and 153 % for the R ewes. Birth weights ranged from 1 kg to 9.8 kg, with a mean of 4.8 kg. Lambs born to F x R ewes (4.28 kg) were significantly lighter at birth than those born to PD x R ewes (5.34 kg). On average, 5 % of lambs were dead at tagging and 11 % of all lambs born were not present at
12 wks of age. The relationship between birth weight and mortality differed to previously published New Zealand reports with high survival rates in the present study over a wide range of birth weights from 3 to 9 kg. It is likely that changes in management practices (improved nutrition, heavier ewes, and selection for easy
care lambing) may have contributed to the reduced mortality rates in the heavier lambs in the present study. Ewe genotype modified the effect of birth rank on birth
weight and mortality. The average penalty for each additional lamb was smaller for the progeny of the EF x R and F x R ewes (0.85 and 0.88 kg, respectively) than
for the progeny of the R and PD x R ewes (1.09 and 1.17 kg, respectively). Triplets born to R ewes had significantly lower survival rates than the other lambs.
Heavier birth weights are likely to result in heavier lambs at 12 weeks of age that can be sold earlier. MenosThis study looked at ewe effects on the number of lambs reared (litter size and mortality) and lamb 12 week weight (birth weight and growth rate). Over six years, data was collected on 5571 lambs born to around 3390 Romney (R), Finn cross Romney (F x R), East Friesian cross Romney (EF x R) and Poll Dorset cross Romney (PD x R) ewes. Ewe live weights were recorded pre-lambing and 12 weeks post-lambing. Lambs were weighed at birth and 12 weeks post-lambing. Ewe effects played a
significant role in affecting the productivity of the system and many effects were cumulative. Over six years, the lambing percentage (lambs born/ewes lambing) was 165 %. Two tooth ewes had lower lambing percentages than the mixed age ewes (155 vs 170 %). Lambing percentages were 186 % for F x R, 171 % for the EF x R,
155 % for the PD x R and 153 % for the R ewes. Birth weights ranged from 1 kg to 9.8 kg, with a mean of 4.8 kg. Lambs born to F x R ewes (4.28 kg) were significantly lighter at birth than those born to PD x R ewes (5.34 kg). On average, 5 % of lambs were dead at tagging and 11 % of all lambs born were not present at
12 wks of age. The relationship between birth weight and mortality differed to previously published New Zealand reports with high survival rates in the present study over a wide range of birth weights from 3 to 9 kg. It is likely that changes in management practices (improved nutrition, heavier ewes, and selection for easy
care lambing) may have contributed to the reduced morta... Presentar Todo |
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Palabras claves : |
RAZAS PROLÍFICAS. |
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Thesagro : |
CORDERO; OVINOS. |
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Asunto categoría : |
L01 Ganadería |
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Marc : |
LEADER 02581nam a2200181 a 4500
001 1053787
005 2015-11-10
008 2004 bl uuuu u01u1 u #d
100 1 $aTHOMSON, B.C.
245 $aLitter size, lamb survival, birth and twelve week weight in lambs born to cross-bred ewes.$h[electronic resource]
260 $aEn: Proceedings of the New Zealand Grassland Association, 66.$c2004
300 $ap. 233-237
520 $aThis study looked at ewe effects on the number of lambs reared (litter size and mortality) and lamb 12 week weight (birth weight and growth rate). Over six years, data was collected on 5571 lambs born to around 3390 Romney (R), Finn cross Romney (F x R), East Friesian cross Romney (EF x R) and Poll Dorset cross Romney (PD x R) ewes. Ewe live weights were recorded pre-lambing and 12 weeks post-lambing. Lambs were weighed at birth and 12 weeks post-lambing. Ewe effects played a significant role in affecting the productivity of the system and many effects were cumulative. Over six years, the lambing percentage (lambs born/ewes lambing) was 165 %. Two tooth ewes had lower lambing percentages than the mixed age ewes (155 vs 170 %). Lambing percentages were 186 % for F x R, 171 % for the EF x R, 155 % for the PD x R and 153 % for the R ewes. Birth weights ranged from 1 kg to 9.8 kg, with a mean of 4.8 kg. Lambs born to F x R ewes (4.28 kg) were significantly lighter at birth than those born to PD x R ewes (5.34 kg). On average, 5 % of lambs were dead at tagging and 11 % of all lambs born were not present at 12 wks of age. The relationship between birth weight and mortality differed to previously published New Zealand reports with high survival rates in the present study over a wide range of birth weights from 3 to 9 kg. It is likely that changes in management practices (improved nutrition, heavier ewes, and selection for easy care lambing) may have contributed to the reduced mortality rates in the heavier lambs in the present study. Ewe genotype modified the effect of birth rank on birth weight and mortality. The average penalty for each additional lamb was smaller for the progeny of the EF x R and F x R ewes (0.85 and 0.88 kg, respectively) than for the progeny of the R and PD x R ewes (1.09 and 1.17 kg, respectively). Triplets born to R ewes had significantly lower survival rates than the other lambs. Heavier birth weights are likely to result in heavier lambs at 12 weeks of age that can be sold earlier.
650 $aCORDERO
650 $aOVINOS
653 $aRAZAS PROLÍFICAS
700 1 $aMUIR, P.D.
700 1 $aSMITH, N.B.
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Registro original : |
INIA Tacuarembó (TBO) |
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