Delivering science for maximum industry benefit: An academic's perspective

This paper discusses some of the factors that contribute to the ability of scientists in the discipline of Animal Science (including Agricultural and Veterinary Sciences) to make significant industry impact. Factors discussed include the need for sound undergraduate training in fundamental sciences taught in an agricultural context and better recognition of industry impact as a metric for scientific achievement and promotion. Funding of program over project-based research is a suggested means for ensuring better impact. Finally, the term 'scientific engineer' is used to describe the 'ideal' scientist that our industries are striving for

The importance of Lean Meat Yield: The value it creates in the supply chain and the importance of better feedback to farmers

Lean meat yield is a key efficiency and profit driver throughout the supply chain. Lamb is sold in lower yielding formats at a retail level (ie more bone and fat) compared to beef, pork and chicken and is typically more expensive, especially when compared on a $/kg lean at retail (Pethick, Ball et al. 2010). High yielding carcases deliver cuts that have a better shape and ensure retailers do not have to present products of overly fat animals for display and sale. For processors a high yielding animal represents increased efficiency in the boning room. These carcases require less labour to trim fat and there is less carcase wastage. For producers, higher yielding animals can be finished to heavier weights without becoming overly fat and accruing penalties. Additionally, fast growing, high yielding animals can be finished either faster or to heavier weights, in a shorter period of time, offering the producer savings on feed costs. The challenge is to produce a fast growing lamb that can be turned off quickly, that are of favourable conformation, and also gives a satisfactory return to the producer. It is increasingly important that price signals reflect not just more carcase as it may represent increasing amounts of fat. With continued evolution of the payment scheme of lamb there is the potential to improve profitability through the use of genetic selection for increased yield

The correlation of intramuscular fat content between muscles of the lamb carcass and the use of computed tomography to predict intramuscular fat percentage in lambs

Intramuscular fat (IMF) % contributes positively to the juiciness and flavour of lamb and is therefore a useful indicator of eating quality. A rapid, non-destructive method of IMF determination like computed tomography (CT) would enable pre-sorting of carcasses based on IMF% and potential eating quality. Given the loin muscle (longissimus lumborum) is easy to sample, a single measurement at this site would be useful, providing is correlates well to other muscles. To determine the ability of CT to predict IMF%, this study used 400 animals and examined 5 muscles from three sections of the carcass: from the fore-section the m. supraspinatus and m. infraspinatus, from the saddle-section the m. longissimus lumborum and from the hind-section the m. semimembranosus and m. semitendinosus. The average CT pixel density of muscle was negatively associated with IMF% and can be used to predict IMF% although precision in this study was poor. The ability of CT to predict IMF% was greatest in the m. longissimus lumborum (slope −0.07) and smallest in the m. infraspinatus (slope −0.02). The correlation coefficients of IMF% between the five muscles were variable, with the highest correlation coefficients evident between muscles of the fore section (0.67 between the m. supraspinatus and the m. infraspinatus) and the weakest correlations were between the muscle of the fore and hind section. The correlation between the m. longissimus lumborum to the other muscles was fairly consistent with values ranging between 0.34 and 0.40 (partial correlation coefficient). The correlation between the proportion of carcass fat and the IMF% of the five muscles varied and was greatest in the m. longissimus lumborum (0.41)

The impact of genetics on retail meat value in Australian lamb

Lean (muscle), fat, and bone composition of 1554 lamb carcasses from Maternal, Merino and Terminal sired lambs was measured using computed tomography scanning. Lamb sires were diverse in their range of Australian Sheep Breeding Values for post weaning c-site eye muscle depth (PEMD) and fat depth (PFAT), and post weaning weight (PWWT). Lean value, representing predicted lean weight multiplied by retail value, was determined for lambs at the same carcass weight or the same age. At the same carcass weight, lean value was increased the most by reducing sire PFAT, followed by increasing PEMD and PWWT. However for lambs of the same age, increasing sire PWWT increased lean value the most. Terminal sired lambs, on average, had greater lean value irrespective of whether comparisons were made at the same age or weight. Lean value was greater in Merino compared to Maternal sired lambs at equal carcass weight, however the reverse was true when comparisons were made at the same age

Intramuscular fat in lamb muscle and the impact of selection for improved carcass lean meat yield

Intramuscular fat percentage (IMF%) has been shown to have a positive influence on the eating quality of red meat. Selection of Australian lambs for increased lean tissue and reduced carcass fatness using Australian Sheep Breeding Values has been shown to decrease IMF% of the Muscularis longissimus lumborum. The impact this selection has on the IMF% of other muscle depots is unknown. This study examined IMF% in five different muscles from 400 lambs (M. longissimus lumborum, Muscularis semimembranosus, Muscularis semitendinosus, Muscularis supraspinatus, Muscularis infraspinatus). The sires of these lambs had a broad range in carcass breeding values for post-weaning weight, eye muscle depth and fat depth over the 12th rib (c-site fat depth). Results showed IMF% to be highest in the M. supraspinatus (4.87±0.1, P<0.01) and lowest in the M. semimembranosus (3.58±0.1, P<0.01). Hot carcass weight was positively associated with IMF% of all muscles. Selection for decreasing c-site fat depth reduced IMF% in the M. longissimus lumborum, M. semimembranosus and M. semitendinosus. Higher breeding values for post-weaning weight and eye muscle depth increased and decreased IMF%, respectively, but only in the lambs born as multiples and raised as singles. For each per cent increase in lean meat yield percentage (LMY%), there was a reduction in IMF% of 0.16 in all five muscles examined. Given the drive within the lamb industry to improve LMY%, our results indicate the importance of continued monitoring of IMF% throughout the different carcass regions, given its importance for eating quality

The impact of beef cattle temperament assessed using flight speed on muscle glycogen, muscle lactate and plasma lactate concentrations at slaughter

This study evaluated the effect of animal temperament measured using flight speed (FS) on plasma lactate, muscle glycogen and lactate concentrations at slaughter plus ultimate pH in 648 lot finished cattle of mixed breed and sex. Muscle samples were collected at slaughter from the m. semimembranosus, m. semitendinosus and m. longissimus thoracis (LT) for analysis of glycogen and lactate concentration. Blood was collected after exsanguination and analysed for plasma lactate concentration and ultimate pH of the LT was measured. FS had no effect on muscle glycogen concentration in any muscle or ultimate pH of the LT (P. >. 0.05). As FS increased from 1 to 5. m/s, plasma and muscle lactate concentration increased by 54% and 11.4% (P. <. 0.01). The mechanisms through which temperament contributes to variation in glycogen metabolism remain unclear. The risk of dark cutting was not impacted by temperament, indicating that other production and genetic factors have a greater impact on the incidence of dark cutting

Starch digestion in ruminents - problems, solutions and opportunities

There have been significant advances in our understanding of starch fermentation and digestion in ruminants. The major problem in feeding starch to ruminants is the rapid fermentation of starch and the accumulation of acids in the gut which reduce the pH to the point where health and productivity are affected. Recent research has identified problems of hindgut acidosis which can be more common and as harmful as the better known problems of lactic acidosis in the rumen. The use of the antibiotic feed additive, virginiamycin, has been shown to reduce the risks of starch feeding to the extent where feeding cereal grain is safe and practical. These new feeding systems have the potential to deliver undigested starch post-ruminally for absorption as glucose. For this reason it has been appropriate to evaluate the effect of glucose on pathways of physiological and commercial importance such as glycogen and lipid synthesis. It is clear that intravenous infusions of glucose stimulate key enzymes involved in lipid synthesis including the citrate cleavage pathway which converts glucose to lipid and importantly acetlyCoA carboxylase, the rate limiting step for lipogenesis

Using indices of skeletal maturity to better understand musculoskeletal development in sheep

Animal maturity is an important concept in the meat industry, with emphasis on producing less mature (i.e. “physiologically younger”) animals with superior carcase characteristics such as greater tenderness and lower fatness. Unfortunately the concept of ‘maturity’ remains poorly defined. Where specified, ‘maturity’ usually refers to some proportion or index expressed relative to the mature state, in which the animal is in anatomical and/or compositional equilibrium. However indices of maturity referenced to body weight or composition (e.g. muscle:bone ratio) are problematic for assessing genotypic effects in modern prime lamb production, where terminal sires may be selected for specific compositional traits such as rapid muscle growth or low body fat. In such cases it may be preferable to define other indices such as skeletal maturity, by staging development in relation to longitudinal bone growth and mineral maturation

The latest eating quality science - managing intramuscular fat and tenderness to improve the consumer experience

This paper discusses the new research and potential implementation phases associated with managing eating quality in Australian lamb. Firstly we discuss the need for electrical stimulation systems as part of lamb processing, especially for supply chains with a domestic focus. We then describe the new eating quality traits being developed in the Sheep CRC Information Nucleus program namely intramuscular fat, shear force tenderness and consumer evaluation using Meat Standards Australia taste panels. Finally we discuss future ways the Industry will underpin and guarantee eating quality of lamb cuts