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Beyond the Bale : December 2017
This project follows on from earlier research into gender bias through nutritional means, which concluded that producers requiring high value breeding females may benefit from feeding omega-6 (eg grains) at joining, whereas those requiring males for meat production may benefit from feeding omega-3 (eg silage or pasture). The original research was led by Dr Edward Clayton of the NSW Department of Primary Industries, Wagga Wagga, along with the Graham Centre, an alliance between NSW DPI and Charles Sturt University (CSU). Dr Clayton is also leading the current project – co -funded by AWI and MLA – along with the Holbrook Landcare Network. “The original research in pen trials that was initiated as part of a PhD conducted by Catherine Gullver from CSU, indicated that, while keeping the same overall energy value of food, ewes fed a diet high in omega-6 pre- and post-joining produce 14% more female lambs than ewes fed a diet high in omega-3,” Dr Clayton said. “Modelling based on those research results indicates that there is potential for considerable economic benefit to producers through minor adjustment to their current management practices. “The purpose of the current research is to paddock validate the results from the original project by replicating the research at 11 properties in NSW in a range of commercial sheep enterprises, and establish best bet management practices. “The project also aims to monitor the impact of feeding the diets high in omega- 3 or omega-6 may have on lamb marking percentages. It will also examine the financial benefit of a change in sex ratio and produce best bet feeding guidelines, using producer case studies.” RESEARCH METHODOLOGY The project commenced in early 2016 and is scheduled to run over three years, with research conducted at five sites in the first year, three sites in the second year, and three sites in the third year. The 11 properties are a mix of sheep-only producers (including Merinos) and mixed farming businesses. A research project is under way to investigate whether feeding ewes at joining with a diet high in omega-6 fatty acids (eg grain) versus high in omega-3 fatty acids (eg silage or pasture) is a viable and practical way to influence the sex ratio of lambs in commercial sheep enterprises. At the research sites, 500 ewes are randomly divided into two groups, with one of those groups of ewes fed only pasture (and/or pasture supplements such as silage or hay), while the other group is supplementary fed oat grain (and potentially wheat, barley, triticale, rye and lupins) in addition to pasture, for four weeks prior to joining and for the first two weeks of joining. Ewes are joined in their groups for 5-6 weeks depending on the normal practice on each of the 11 properties. REBUILDING SHEEP FLOCKS “If the project proves successful and economically viable, this will be beneficial for producers in the Australian sheep industry, especially for woolgrowers needing to rebuild flock numbers against a background of high replacement ewe prices and cash flow restrictions,” said AWI Program Manager, Farm Automation & Reproduction, Carolina Diaz. “In commercial terminal meat enterprises, the producers would benefit from a bias to male progeny, since replacement females are simply purchased from time to time.” As part of the project, producers partaking in the trial, plus surrounding producers, are being interviewed to identify what influence this feeding practice could have on commercial sheep enterprises. The survey of producers aims to determine their level of interest in influencing the gender ratio of their flock, how applicable the practice is in their business, the situations where the producers would use this practice, the impacts it would have on their business, any barriers to adoption and potential strategies to overcome those barriers. “The aim of the project is to not only explore the validity of gender bias by variation in feed, but also to produce costed practical recommendations for commercial enterprises to consider,” Ms Diaz added. Female lamb versus male lamb: If you want your enterprise’s breeding program to produce a higher proportion of lambs of a particular sex, then keep an eye on an AWI co-funded project that could potentially validate breakthrough research into gender bias breeding. 36 ON FARM
In the Shops - March 2018