Abstract
At the time of joining, sheep commonly graze pasture which is high in omega-3 fatty acids. If pasture supply is limited, supplements such as grain that are high in omega-6 fatty acids may be fed. Therefore, the aim of the current paper was to review dietary sources of fatty acids in the diet of sheep in south-east Australia and the contribution of these fatty acids to reproduction and, specifically, the
sex of lambs. In a series of studies, Merino x Border Leicester or Merino ewes were allocated to one of two dietary treatments, 100% silage (low in omega-6 and high in omega-3) or 70% oat grain and 8% cottonseed meal (CSM, high in omega-6). In study 1, ewes consumed the diets for 44 days prior to
the assessment of the prostaglandin (PGF2α) response to an oxytocin challenge. In studies 2−4, ewes consumed the diets for approximately six weeks prior to and 17 days following joining to assess the effect of diet on the sex ratio of lambs. Plasma omega-6 was higher (P <0.001), PGF2α response to oxytocin was greater (P <0.05), the time to behavioural oestrus was shorter (P =0.006) and the proportion of female lambs was increased (58.2 versus 43.5%, P = 0.010) when ewes were fed the oat grain/CSM compared with the silage diet. Targeted feeding of oats at joining may provide a practical way for
producers to manipulate the sex ratio of their flock in favour of females.
Original language | English |
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Title of host publication | Driving Your Landscape to Success |
Subtitle of host publication | Managing a Grazing Business for Profit in the Agricultural Landscape |
Editors | C Harris, G Lodge, C Waters |
Place of Publication | Orange, NSW |
Publisher | The Grassland Society of NSW Inc. |
Pages | 107-113 |
Number of pages | 7 |
ISBN (Print) | 9781742563039 |
Publication status | Published - 2012 |
Event | 27th Annual Conference of the Grassland Society of NSW Inc.: Driving Your Landscape to Success - Charles Sturt University, Wagga Wagga , Australia Duration: 24 Jul 2012 → 26 Jul 2012 http://grasslandnsw.com.au/FreeContent/2012/2012_Conference_Prelims.pdf |
Conference
Conference | 27th Annual Conference of the Grassland Society of NSW Inc. |
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Abbreviated title | Managing a Grazing Business for Profit in the Agricultural Landscape |
Country/Territory | Australia |
City | Wagga Wagga |
Period | 24/07/12 → 26/07/12 |
Internet address |