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Beyond the Bale : September 2018
ON FARM 57 An AWI-funded research project aims to improve the success rates and reliability of artificial insemination (Al) programs. For many years laparoscopic AI using frozen semen has produced highly variable results. The good results have been OK, but the bad results have often been very bad and producers have been walking away from the technology. Investigations to date have been unable to explain the large variation in conception rates between sites but have pointed to several likely causes and possible remedies. New AWI-funded research aims to address several of these issues by developing new treatment protocol(s) that are able to consistently produce improved levels of synchrony of oestrus. It is anticipated that this new treatment protocol will replace the existing standard treatment protocol that has remained largely unchanged since the 1970s. By examining the effects of body condition scores, feed intakes and progesterone concentrations on synchrony of oestrus, the project also aims to develop improved management strategies for Al programs. The AWI-funded research, which is due to run until the middle of next year, is being carried out through the South Australian Research and Development Institute (SARDI) by Dr Simon Walker, Dr Dave Kleemann and Dr Jen Kelly. Semen quality has often been blamed for the variable success rates of AI programs. However, while semen quality is one of a number of factors that need to be optimised, Dr Walker says it is highly unlikely to be a major reason for the poor results. “Substantial research into semen quality has been conducted over the past 30–40 years and AI results today are no better than they were back then – in fact, they are probable worse,” he said. “When it takes up to 4–5 days for all sheep in a flock to come into oestrus, as can occur, semen quality loses a lot of its relevance – sperm simply don’t survive that long after insemination.” REASSESSING THE CURRENT SYNCHRONISATION PROTOCOL Dr Walker says the current synchronisation protocol (CIDR for 14 days followed by PMSG), which has long been presumed by the sheep industry to routinely produce a good synchrony, needs reassessment. “This dogma reaches far and wide within the industry. The reality is much different – there are good, average and bad synchronies across flocks with matching pregnancy rates. A good rule of thumb is ‘a good synchrony produces a good result’. One of the challenges of this project is to identify the reasons for this variability and to develop protocols that are more reliable.” Dr Kleeman says that ewe nutrition is a factor that potentially influences synchrony of oestrus. “However, we are betting that it is the effect of long term rather than short term nutrition that is important,” he said. “Of particular interest is the ability of the ewe to recover body condition following the previous lambing/lactation. If there is substance in this notion, it would indicate that flocks in the more marginal areas of the country might experience greater variable in their AI results. We’ll be looking at various aspects of this topic utilising ewes that lambed in autumn.” Dr Kleeman says sheep have changed substantially during the fifty or so years since the development of the original protocol, so it is possible that body size is another factor influencing the ability to synchronise sheep. “Ewes are substantially bigger, perhaps fatter and many are dual purpose in nature,” he said. “These changes raise issues such as dose rates of the treatment hormones and the effects that selection for growth rate might have on components of reproduction including the ability to synchronise oestrus.” EARLY RESULTS ARE ENCOURAGING A large part of the study involves examination of the ovary during the period of hormone treatment and to determine what happens after the CIDR is removed. “These observations are being done using ultrasound and the thousands of images so far collected show that, at the time of CIDR removal, there is a lot of different activity on the surface of the ovary – for example some have lots of follicles, others have few follicles, some follicles are growing whilst others are regressing,” Dr Walker said. “We are correlating these differences with time of onset of oestrus to determine if there is a ‘preferred’ ovarian status at the time of CIDR removal. This information will provide a sound basis for the development of new protocols – we have already been able to shift the pattern of synchrony by up to 12 hours and this adds to our confidence that new protocols will be developed.” Once the research is complete, the outcomes will be reported through field days, seminars and updates to commercial companies. An extension package including a best practice manual will also be produced for veterinarians and sheep breeders to help adoption of the technical advances. IMPROVING THE SUCCESS OF SHEEP AI PROGRAMS As part of the project, a national survey of AI results/programs is being conducted by the SA Stud Merino Breeders Association (Merino SA) to help not only measure success rates, but also identify problems within regional areas and to identify flocks (those with good and bad results) that might help in the development of new strategies to improve success rates. YOUR CHANCE TO GET INVOLVED IN THE 2018 NATIONAL LAPAROSCOPIC AI SURVEY If you are a sheep breeder in Australia who has used laparoscopic AI in recent years, you are encouraged to complete the survey, available on the Merino SA website at www.merinosa.com.au For further information about the survey, contact Merino SA committee member Ian Rowett on 0418 486 050 or email@example.com Researchers Dr Simon Walker and Dr Dave Kleemann at the SA Merino Sire Evaluation Trial field day in June at Keyneton Station, at which they spoke to attendees about the AWI-funded project. PHOTO: Stock Journal Weight gain at the touch of a finger. 1800 GALLAGHER www.gallagher.com Touch screen Weigh Scales • Simple to operate touch screen Weigh Scales • Collect data to optimise animal performance For more information on our full range of Weighing and EID Systems, contact Gallagher on 1800 425 524. Track individual animal fleece performance such as micron, staple strength, or greasy fleece weight in the shed. Make management decisions based on individual and accurate animal data collected over a life time. 123 456 789 ABC 0 TW-1 TW-3 TWR-5 SUNLIGHTREADABLELCDTOUCHSCREEN
In the Shops - September 2018