These notes are created around the technology and practices that the Sheep CRC has investigated, thus they are not intended to cover all aspects of sheep management. However, you can expect more new notes at this site as we convert our research results into useful information.

QUALITY SHEEP MEAT SERIES

Quality Sheepmeat - Reducing dehydration in slaughter lambs

• Dehydration is common in slaughter lambs, particularly sucker lambs.
• Dehydrated lambs have lower meat yields due to loss in muscle weight.
• Losses in muscle weight mean reduced returns to both the producer and the processor.
• Dehydration in slaughter lambs can be reduced.

• Optimising the rate of pH and temperature decline improves sheep meat eating quality.
• Meat Standards Australia (MSA) for Sheep Meat will require meat processors to measure and control systems to achieve the optimum pH-temperature window.
• To determine the proportion of carcases hitting the window, four times each year, processors should select and monitor four consignments with 25 carcases per consignment.
• pH should be recorded 20 to 30 minutes post slaughter and again when the carcase is close to 18^oC.

• Lamb finishing strategies and curfew management can affect producer returns, carcase traits and meat quality.
• Vitamin E supplements for two to four weeks prior to slaughter can improve shelf life.
• Magnesium oxide supplements for only four days prior to slaughter can reduce the effects of stress on glycogen reserves and may be particularly useful when finishing Merino lambs.
• Feeding high quality diets for 14 days pre-slaughter to ensure weight gain can improve meat qualities such as juiciness and tenderness.
• Curfew periods should not exceed 24 hours.
• Ensuring lambs have access to and experience with water troughs will help reduce carcase weight loss.
• Total time off feed prior to slaughter should not exceed 48 hours.

• Selection for eye muscle growth (PEMD) decreases the length of the leg bones and specific sire selection for muscling may shorten the legs.
• Single trait selection for muscling may have the consequence of shrinking the skeletal frame and this underpins the need to use a multi trait selection approach.

• Meat eating quality is important for consumers’ choice of lamb over other meats. 
• Whilst processing effects are significant, so are on farm practices.
• Age at slaughter, nutrition and genetics impact on the quality of meat.

• Electrical stimulation enhances meat quality by improving tenderness and meat colour and is helping Australian processors to consistently deliver quality sheep meat.
• A number of electrical inputs are available to improve meat quality.
• Medium voltage electrical stimulation units at the start and the end of the chain can improve tenderness and meat colour by increasing the rate of pH decline.
• High frequency immobilisation at the start of the chain reduces animal movement and improves occupational health and safety.
• Low or medium voltage electrical stimulation at the start of the chain can increase the amount of collectable blood and also reduces waste.

• A number of breeds and their crosses contribute to the sheepmeat industry in Australia.
• Traditionally, these include the Merino, the Border Leicester and the terminal sire breeds such as the Poll Dorset.
• Differences in carcase and growth characteristics between genotypes contribute to how quickly they reach carcase weight and to their carcase value measured as lean meat yield, loin weight and deposition of fat.

• Mutton and some lamb can have a distinctive mutton odour and flavour that is unattractive to consumers.
• This odour is caused by branched chain fatty acids.
• Reducing the levels of branch chain fatty acids will increase appeal to consumers.
• Substitution of mutton for lamb occurs and detracts from the reputation of lamb as a quality product.
• Managing nutrition and genetics has the potential to reduce these fatty acids in sheep.

• Carcase weights can be significantly increased by using sires that are genetically superior for weight.
• Use of high growth sires also has an impact on mature weights, carcase composition and the performance of lambs under high and low nutrition.
• Using sires selected concurrently for muscle and growth, will increase lean meat yield, reduce fat and improve feed conversion efficiency.

• Sheepmeat with a high pH can be less acceptable to consumers, both in appearance and eating quality.
• A high muscle pH results after slaughter due to insufficient glycogen (energy) in the muscles at slaughter.
• Merinos are more susceptible to high pH meat but management and breeding can reduce the incidence of such meat.

• Consumers’ decisions to buy meat are strongly influenced by their perception of colour. 
• The stability of meat colour is affected by a number of on-farm, processing and retail display practices. 
• Changing some of these practices along the supply chain can therefore improve colour stability, and hence shelf-life, with potentially significant cost savings at the retail level.