Increasing the proportion of female lambs by supplementary feeding oats high in omega-6 fatty acids at joining

Edward Clayton, Catherine Gulliver, John Wilkins, Belinda King, R.J. Meyer, Michael Friend

Research output: Book chapter/Published conference paperConference paper

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 languageEnglish
Title of host publicationDriving Your Landscape to Success
Subtitle of host publicationManaging a Grazing Business for Profit in the Agricultural Landscape
EditorsC Harris, G Lodge, C Waters
Place of PublicationOrange, NSW
PublisherThe Grassland Society of NSW Inc.
Pages107-113
Number of pages7
ISBN (Print)9781742563039
Publication statusPublished - 2012
Event27th Annual Conference of the Grassland Society of NSW Inc.: Driving Your Landscape to Success - Charles Sturt University, Wagga Wagga , Australia
Duration: 24 Jul 201226 Jul 2012
http://grasslandnsw.com.au/FreeContent/2012/2012_Conference_Prelims.pdf

Conference

Conference27th Annual Conference of the Grassland Society of NSW Inc.
Abbreviated titleManaging a Grazing Business for Profit in the Agricultural Landscape
CountryAustralia
CityWagga Wagga
Period24/07/1226/07/12
Internet address

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    Clayton, E., Gulliver, C., Wilkins, J., King, B., Meyer, R. J., & Friend, M. (2012). Increasing the proportion of female lambs by supplementary feeding oats high in omega-6 fatty acids at joining. In C. Harris, G. Lodge, & C. Waters (Eds.), Driving Your Landscape to Success: Managing a Grazing Business for Profit in the Agricultural Landscape (pp. 107-113). The Grassland Society of NSW Inc.. http://www.grasslandnsw.com.au/FreeContent/2012/13-2012-Clayton.pdf