The effect of peri-conceptual grazing of live pasture on fetal numbers in unsynchronised ewes

Susan Robertson, Belinda King, Maxwell Allworth, Jessica Rummery, Michael Friend

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Abstract

Methods of increasing the number of lambs born per ewe that avoid the use of pharmaceutical methods of oestrus synchronisation but which require a short period of increased nutrition are desirable. Four separate experiments evaluated whether peri-conceptual grazing of lucerne, compared with senescent herbage or other live herbage, increased fetal numbers in unsynchronised ewes. Merino ewes that grazed lucerne pasture for seven days before joining and for the first seven days of a five to six week joining produced up to 21 extra (P<0.05) fetuses per 100 ewes joined, compared with ewes grazing cereal stubble with minimal live herbage (experiment 2). In experiments 1, 3 and 4, Merino or First Cross ewes grazing either cereal stubbles or phalaris pasture with as little as 200 kg DM/ha of live herbage produced a similar (P>0.05) number of fetuses per ewe joined as those grazing on lucerne, either because this quantity of live feed was sufficient to increase fetal numbers, or because, for experiment 3, First Cross ewes may not have responded at the commencement of the breeding season. It is concluded that grazing live pasture for seven days prior to joining and for the first seven days of joining during the breeding season can substantially increase fetal numbers in unsynchronised ewes compared to ewes grazing stubbles containing no live herbage. The response appears to occur on a range of plant species, and a small quantity of live herbage can elicit a response. Grazing lucerne in the peri-conceptual period did not increase (P>0.05) the proportion of non-pregnant ewes. Further studies are required to determine how early in the breeding season ewes with a distinct breeding season will respond to nutritional manipulation.
Original languageEnglish
Pages (from-to)1008-1015
Number of pages8
JournalAnimal Production Science
Volume54
Issue number8
Early online date2013
DOIs
Publication statusPublished - Nov 2014

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Medicago sativa
Breeding
ewes
pastures
grazing
alfalfa
breeding season
Estrus Synchronization
forage
Fetus
live feeds
estrus synchronization
Pharmaceutical Preparations
Merino
fetus
lambs
nutrition
drugs

Cite this

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title = "The effect of peri-conceptual grazing of live pasture on fetal numbers in unsynchronised ewes",
abstract = "Methods of increasing the number of lambs born per ewe that avoid the use of pharmaceutical methods of oestrus synchronisation but which require a short period of increased nutrition are desirable. Four separate experiments evaluated whether peri-conceptual grazing of lucerne, compared with senescent herbage or other live herbage, increased fetal numbers in unsynchronised ewes. Merino ewes that grazed lucerne pasture for seven days before joining and for the first seven days of a five to six week joining produced up to 21 extra (P<0.05) fetuses per 100 ewes joined, compared with ewes grazing cereal stubble with minimal live herbage (experiment 2). In experiments 1, 3 and 4, Merino or First Cross ewes grazing either cereal stubbles or phalaris pasture with as little as 200 kg DM/ha of live herbage produced a similar (P>0.05) number of fetuses per ewe joined as those grazing on lucerne, either because this quantity of live feed was sufficient to increase fetal numbers, or because, for experiment 3, First Cross ewes may not have responded at the commencement of the breeding season. It is concluded that grazing live pasture for seven days prior to joining and for the first seven days of joining during the breeding season can substantially increase fetal numbers in unsynchronised ewes compared to ewes grazing stubbles containing no live herbage. The response appears to occur on a range of plant species, and a small quantity of live herbage can elicit a response. Grazing lucerne in the peri-conceptual period did not increase (P>0.05) the proportion of non-pregnant ewes. Further studies are required to determine how early in the breeding season ewes with a distinct breeding season will respond to nutritional manipulation.",
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The effect of peri-conceptual grazing of live pasture on fetal numbers in unsynchronised ewes. / Robertson, Susan; King, Belinda; Allworth, Maxwell; Rummery, Jessica; Friend, Michael.

In: Animal Production Science, Vol. 54, No. 8, 11.2014, p. 1008-1015.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The effect of peri-conceptual grazing of live pasture on fetal numbers in unsynchronised ewes

AU - Robertson, Susan

AU - King, Belinda

AU - Allworth, Maxwell

AU - Rummery, Jessica

AU - Friend, Michael

N1 - Includes bibliographical references.

PY - 2014/11

Y1 - 2014/11

N2 - Methods of increasing the number of lambs born per ewe that avoid the use of pharmaceutical methods of oestrus synchronisation but which require a short period of increased nutrition are desirable. Four separate experiments evaluated whether peri-conceptual grazing of lucerne, compared with senescent herbage or other live herbage, increased fetal numbers in unsynchronised ewes. Merino ewes that grazed lucerne pasture for seven days before joining and for the first seven days of a five to six week joining produced up to 21 extra (P<0.05) fetuses per 100 ewes joined, compared with ewes grazing cereal stubble with minimal live herbage (experiment 2). In experiments 1, 3 and 4, Merino or First Cross ewes grazing either cereal stubbles or phalaris pasture with as little as 200 kg DM/ha of live herbage produced a similar (P>0.05) number of fetuses per ewe joined as those grazing on lucerne, either because this quantity of live feed was sufficient to increase fetal numbers, or because, for experiment 3, First Cross ewes may not have responded at the commencement of the breeding season. It is concluded that grazing live pasture for seven days prior to joining and for the first seven days of joining during the breeding season can substantially increase fetal numbers in unsynchronised ewes compared to ewes grazing stubbles containing no live herbage. The response appears to occur on a range of plant species, and a small quantity of live herbage can elicit a response. Grazing lucerne in the peri-conceptual period did not increase (P>0.05) the proportion of non-pregnant ewes. Further studies are required to determine how early in the breeding season ewes with a distinct breeding season will respond to nutritional manipulation.

AB - Methods of increasing the number of lambs born per ewe that avoid the use of pharmaceutical methods of oestrus synchronisation but which require a short period of increased nutrition are desirable. Four separate experiments evaluated whether peri-conceptual grazing of lucerne, compared with senescent herbage or other live herbage, increased fetal numbers in unsynchronised ewes. Merino ewes that grazed lucerne pasture for seven days before joining and for the first seven days of a five to six week joining produced up to 21 extra (P<0.05) fetuses per 100 ewes joined, compared with ewes grazing cereal stubble with minimal live herbage (experiment 2). In experiments 1, 3 and 4, Merino or First Cross ewes grazing either cereal stubbles or phalaris pasture with as little as 200 kg DM/ha of live herbage produced a similar (P>0.05) number of fetuses per ewe joined as those grazing on lucerne, either because this quantity of live feed was sufficient to increase fetal numbers, or because, for experiment 3, First Cross ewes may not have responded at the commencement of the breeding season. It is concluded that grazing live pasture for seven days prior to joining and for the first seven days of joining during the breeding season can substantially increase fetal numbers in unsynchronised ewes compared to ewes grazing stubbles containing no live herbage. The response appears to occur on a range of plant species, and a small quantity of live herbage can elicit a response. Grazing lucerne in the peri-conceptual period did not increase (P>0.05) the proportion of non-pregnant ewes. Further studies are required to determine how early in the breeding season ewes with a distinct breeding season will respond to nutritional manipulation.

KW - Flushing

KW - Nutrition

KW - Reproduction

KW - Sheep

U2 - 10.1071/AN13086

DO - 10.1071/AN13086

M3 - Article

VL - 54

SP - 1008

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JO - Animal Production Science

JF - Animal Production Science

SN - 1836-0939

IS - 8

ER -