ON FARM SHEEP REPRODUCTIVE EFFICIENCY Looking deeperRESEARCH INREVIEW into dystocia PROJECT NAMEA review of maternal dystocia Dystocia – orbirth injury – RESEARCH ORGANISATIONS Murdoch University, David Masters, is a major cause of lamb NSW Department of Primary and ewe mortality, but Industries, Massey University (NZ), producers can improve survival John Young, UWA through strategic management. FUNDING ORGANISATIONS A new MLA‑funded study has revealed MLA birth injury plays a far greater role in GOAL lamb mortality than previously realised. 1. Determine risk factors for dystocia Dr Caroline Jacobson from Murdoch in the Australian sheep flock University collaborated on the review 2. Estimate economic impact of Australian lamb survival studies of dystocia conducted since 1990. 3. Identify opportunities to “More than 75% of lamb deaths reduce the impact of dystocia associated with dystocia have no in Australian sheep production external evidence that most producers systems would recognise as dystocia injury, 4. Identify gaps and propose new such as a swollen head or neck,” R&D priorities to reduce the Dr Jacobson said. very low or very high birth weight,” impacts of dystocia Dr Jacobson said. “Their birth injuries were only found by BUDGET careful post‑mortem examination of the As well as sourcing genetics which $34,323 (plus in‑kind contributions brain and spinal cord.” contribute to increased lamb survival, to total project value $89,054) it’s important to condition‑score ewes. Dystocia is a significant animal welfare DURATION issue and comes with considerable “Maiden ewes, in particular, 23 February – 1 May 2020 financial costs. should be managed to KEY FINDINGS TO DATE “Ewe and lamb deaths related to dystocia reach weight and condition • Dystocia is a significant animal are estimated to reduce farm income by welfare issue and comes with $16per ewe,” Dr Jacobson said. score targets at mating to considerable financial costs. Best practice management avoid having ewes that are • Strategies already recommended Although there are still many unknowns undersized at lambing.” to improve lamb survival are around how best to reduce dystocia, beneficial to reduce dystocia, with Dr Jacobson said strategies already Scanning pregnant ewes is another good management beginning recommended to improve lamb survival crucial strategy to increase survival. long before lambing. are beneficial, with good management “Separating single and twin‑bearing beginning long before lambing. ewes enables differential management “Paddocks for lambing should contain “When selecting rams, it’s a good idea to avoid ewes being too fat or too adequate shelter, especially for twins to discuss with ram breeders how the thin at lambing. Ewes need to be and triplets, and good feed if possible,” Australian Sheep Breeding Values well‑nourished but not fat.” she said. (ASBV) for birth weight and lambing Working with an animal health ease will complement your ewe type Minimise disturbance during lambing, and age,” Dr Jacobson said. advisor or veterinarian so ewes have such as when supplementary feeding or appropriate mineral supplements in late from other sheep by reducing mob size “Traditionally, dystocia has been seen pregnancy can help reduce dystocia for twins and triplets. ■ as a problem in single‑born lambs with caused by nutritional, metabolic and large birth weight, but it’s actually a hormonal imbalances. significant contributor to lamb deaths Dr Caroline Jacobson across all litter sizes. Dr Jacobson also recommends E: c.jacobson@murdoch.edu.au checking pastures for oestrogenic Read a summary of this project at “The ideal lamb birth weight varies clovers and managing ewes’ exposure mla.com.au/maternal‑dystocia‑ between breeds and birth types, with to these paddocks, as it can impact review dystocia risk increased for lambs with their hormone levels. 26