Biological Control of Citrus Huanglongbing with EB92-1, a Benign Strain of Xylella fastidiosa.

Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus, is currently the most destructive disease of citrus and threatens production in all affected areas. There is no cure. Benign Xylella fastidiosa strain EB92-1 provided good control of Pierce's disease of grapevine by inducing host resistance; therefore, we evaluated the strain for the biological control of HLB in citrus. Treatment was by injection into the trunk of the trees. Strain EB92-1 was shown to colonize citrus and provided control of HLB by reducing both the incidence of symptomatic trees and the percentage of trees with severe symptoms in three separate trials. All trees were positive by quantitative PCR (qPCR) for Candidatus Liberibacter asiaticus at the start of the trials, and treatment did not eliminate the bacterium. In a trial of asymptomatic mature trees, a single treatment with EB92-1 reduced the incidence of trees with symptoms through 18 months after treatment and reduced the incidence of trees with severe symptoms through 3 years. In mature trees that had 60% incidence of mild HLB symptoms at trial initiation, percentage of trees with symptoms and trees with severe symptoms continued to develop in both the untreated and in the EB92-1-treated trees for 12 months. However, retreatment at 9 and 20 months prevented the development of additional severe symptoms in the EB92-1-treated trees throughout the remainder of the 5-year trial. In 2-year-old trees, incidence of trees with HLB symptoms was higher in the untreated trees than in the treated trees throughout the 6 years of the trial, reaching 90% in the untreated versus 50% in the treated. After 6 years, severity of symptoms was much lower in the EB92-1-treated trees, only 3% of the treated trees had become unproductive compared with 18% of the untreated. In 2020, the reduction in HLB severity resulted in approximately twice as much yield in the treated trees as in these untreated 8-year-old trees. X. fastidiosa strain EB92-1 proved to be efficacious for the control of HLB symptoms in both mature trees and newly planted young trees, but trees may need to be retreated yearly for at least the first 2 to 3 years.

Genetic variation in colour stability traits of lamb cuts under two packaging systems.

Data from samples of longissmus lumborum (LL) and semimembranosus (SM) muscles from 391 lamb carcasses, which had been packaged in overwrap (OW) or high oxygen modified atmosphere packaging (MAPO2) systems and then subjected to simulated retail display, were used to estimate genetic variation for colour stability traits of lamb meat as a step in identifying a trait for genetic evaluation. Traits included the ratio of the reflectance of light at wavelengths of 630 nm and 580 nm (oxy/met) measured at a single time point at the end of the display period (day 3 under OW; day 8 under MAPO2) and the predicted time for oxy/met to reach a benchmark value. Under OW and MAPO2, the measures of meat colour stability of the LL tended to be of moderate heritability (0.09-0.29), but for the SM were of low heritability (0-0.10). Improving retail colour stability of lamb loins through selection of genetically superior animals may be better based on measurement of oxy/met.

Comparison of a grain-based diet supplemented with synthetic vitamin E versus a lucerne (alfalfa) hay-based diet fed to lambs in terms of carcass traits, muscle vitamin E, fatty acid content, lipid oxidation, and retail colour of meat.

Dietary supplementation of vitamin E (VitE) in a synthetic or natural form was examined. Forty-eight lambs were assigned (n = 16) to either a grain-based diet at moderate (MOD, 42 mg∙kg-1 VitE as all-rac α-tocopheryl acetate) or supranutritional (SUP, 285 mg∙kg-1 of vitE) levels of synthetic VitE or a lucerne hay-based diet (LUC; 37 mg∙kg-1 VitE) for 8 weeks. Meat from the LUC group had lower muscle n-6 and PUFA levels compared to meat from the MOD and SUP groups. Despite a similar VitE intake, muscle VitE was higher for LUC compared to MOD, while SUP lambs showed the highest VitE. Lipid oxidation did not differ between groups. For fresh meat, redness tended to be higher in LUC fed lambs than the other two groups, but brownness formation was only lower than the SUP group. For aged meat colour stability, redness tended to be higher in lambs fed SUP and LUC, whereas highest browning occurred in the MOD group.

Increasing omega-3 levels in meat from ruminants under pasture-based systems.

This review discusses the importance of red meat from ruminants as a source of omega-3 (n-3) fatty acids (FAs) for human life in the context of the contribution of animals to human welfare. Red meat is a valuable food commodity for human life because it is naturally rich in key nutrients such as protein, trace elements, vitamins and essential FAs. In developed countries and high socio-economic groups from developing countries, red meat intake is greater than that of oily fish, owing to availability, preference and affordability. Omega-3 FA concentration is higher in red meat (beef, lamb and mutton) than in white meat (pork, poultry and turkey), due to the fibre types present in muscle tissues and the specialised digestive systems of ruminants. There is mounting evidence that regular consumption of n-3 FAs is beneficial for growth and development as well as the health and welfare of humans of all ages. The dietary background of ruminants significantly influences the concentration of n-3 FAs in red meat. Meat from forage- or grassfed ruminants has a greater concentration of n-3 FAs than that from their feedlot or grain-fed counterparts and can also offer a favourable n-6:n-3 ratio in the meat. Scientific literature shows that the advantages of consuming n-3 FAs enriched meat (foods) outweigh the disadvantages.

Dans le cadre de l'analyse de la contribution des animaux au bien-être de l'homme, les auteurs examinent l'importance pour l'alimentation humaine des acides gras oméga-3 présents dans la viande rouge provenant de ruminants. La viande rouge est une denrée alimentaire précieuse pour l'organisme humain, étant naturellement riche en plusieurs nutriments majeurs tels que protéines, oligo-éléments, vitamines et acides gras essentiels. Dans les pays développés et dans les classes aisées au plan socio-économique des pays en développement, la consommation de viande rouge dépasse celle de poissons gras pour des raisons de disponibilité, de préférence et de prix. La teneur en acides gras oméga-3 est plus élevée dans les viandes rouges (boeuf, agneau et mouton) que dans les viandes blanches (porc, volaille et dinde) du fait des caractéristiques des fibres des tissus musculaires des ruminants et de leur système digestif spécialisé. Il y a de plus en plus d'indices démontrant qu'une consommation régulière d'acides gras oméga-3 est bénéfique pour la croissance et le développement ainsi que pour la santé et le bien-être de l'être humain à tous les âges de sa vie. Le contexte de l'alimentation des ruminants influence de manière significative la teneur en acides gras oméga-3 de la viande rouge. La viande issue de ruminants nourris de fourrage ou à l'herbe présente une concentration plus élevée d'acides gras oméga-3 que celle de leurs homologues des parcs d'engraissement ou nourris au grain, ainsi qu'un ratio oméga 6/oméga-3 favorable. La littérature scientifique montre que la consommation de viandes (ou autres aliments) riches en acides gras oméga-3 apporte plus de bénéfices que d'inconvénients.

Considerando la cuestión desde el ángulo de la contribución de los animales al bienestar humano, los autores examinan la importancia que reviste para la vida humana la carne roja de rumiante como fuente de ácidos grasos omega-3 (n-3). Por su elevado contenido natural en nutrientes fundamentales como proteínas, oligoelementos, vitaminas y ácidos grasos esenciales, la carne roja es un artículo alimentario de gran valor para la vida humana. En los países desarrollados, al igual que entre las élites socioeconómicas de los países en desarrollo, la ingesta de carne roja es superior a la de pescado azul, por razones de disponibilidad, preferencia y asequibilidad. Por los tipos de fibra presentes en el tejido muscular de los rumiantes y por el carácter especializado de su sistema digestivo, la concentración de ácidos grasos omega-3 es mayor en la carne roja (bovinos y ovinos) que en la carne blanca (cerdo, pollo y pavo). Cada vez hay más datos demostrativos de que el consumo regular de ácidos grasos n-3 es beneficioso para el crecimiento, el desarrollo, la salud y el bienestar de las personas a cualquier edad. El tipo de alimentación de un rumiante influye sensiblemente en la concentración de ácidos grasos n-3 que presentará su carne: la carne de rumiantes que han forrajeado o pastado en campos de hierba tiene mayor concentración de esos ácidos grasos que la de sus homólogos procedentes de establos de engorde o alimentados con grano, además de presentar en ocasiones una proporción más favorable entre n-6 y n-3. Los estudios científicos publicados ponen de relieve que el consumo de carne (u otros alimentos) enriquecida en ácidos grasos n-3 tiene más ventajas que inconvenientes.

Genetic correlations between wool traits and meat quality traits in Merino sheep.

Genetic correlations between 29 wool production and quality traits and 25 meat quality and nutritional value traits were estimated for Merino sheep from an Information Nucleus (IN). Genetic correlations among the meat quality and nutritional value traits are also reported. The IN comprised 8 flocks linked genetically and managed across a range of sheep production environments in Australia. The wool traits included over 5,000 yearling and 3,700 adult records for fleece weight, fiber diameter, staple length, staple strength, fiber diameter variation, scoured wool color, and visual scores for breech and body wrinkle. The meat quality traits were measured on samples from the and included over 1,200 records from progeny of over 170 sires for intramuscular fat (IMF), shear force of meat aged for 5 d (SF5), 24 h postmortem pH (pHLL; also measured in the , pHST), fresh and retail meat color and meat nutritional value traits such as iron and zinc levels, and long-chain omega-3 and omega-6 polyunsaturated fatty acid levels. Estimated heritabilities for IMF, SF5, pHLL, pHST, retail meat color lightness (), myoglobin, iron, zinc and across the range of long-chain fatty acids were 0.58 ± 0.11, 0.10 ± 0.09, 0.15 ± 0.07, 0.20 ± 0.10, 0.59 ± 0.15, 0.31 ± 0.09, 0.20 ± 0.09, 0.11 ± 0.09, and range of 0.00 (eicosapentaenoic, docosapentaenoic, and arachidonic acids) to 0.14 ± 0.07 (linoleic acid), respectively. The genetic correlations between the wool production and meat quality traits were low to negligible and indicate that wool breeding programs will have little or no effect on meat quality. There were moderately favorable genetic correlations between important yearling wool production traits and the omega-3 fatty acids that were reduced for corresponding adult wool production traits, but these correlations are unlikely to be important in wool/meat breeding programs because they have high SE, and the omega-3 traits have little or no genetic variance. Significant genetic correlations among the meat quality traits included IMF with SF5 (-0.76 ± 0.24), fresh meat color * (0.50 ± 0.18), and zinc (0.41 ± 0.19). Selection to increase IMF will improve meat tenderness and color which may address some of the issues with Merino meat quality. These estimated parameters allow Merino breeders to combine wool and meat objectives without compromising meat quality.

The effect of applying a rinse and chill procedure to lamb carcases immediately post-death on meat quality?

The current study examined the effect of vascular rinsing lamb carcases (Rinse & Chill®) with a commercially available isotonic substrate solution (98.5% water; balance: glucose, polyphosphates, and maltose) at 14°C. Thirty, lamb carcases were randomly allocated to receive either the solution (n=15) 25 min post slaughter on a slaughter line or no solution (n=15). There was no apparent effect on the rate of pH decline due to infusion or muscle shortening of the M. longissimus thoracis et lumborum (LL), but there was a more than 50% reduction in toughness (lower shear force) of the LL due to infusion. Infusion resulted in lighter (L*), yellower (b*) LL and this effect was maintained during simulated colour display. There was no impact on redness (a*) of the LL and in fact a critical consumer threshold for redness was not breached on average for infused or non-infused LL. There was no evidence of elevated levels of metmyoglobin formation or lipid oxidation.

Genetic correlations between wool traits and carcass traits in Merino sheep.

Genetic correlations between 29 wool production and quality traits and 14 whole carcass measures and carcass component traits were estimated from the Information Nucleus of 8 flocks managed across a range of Australian sheep production environments and genetically linked. Wool data were from over 5,000 Merino progeny born over 5 yr, whereas carcass data were from over 1,200 wether progeny of over 176 sires, slaughtered at about 21 kg carcass weight, on average. Wool traits included yearling and adult records for wool weight, fiber diameter, fiber diameter variation, staple strength, scoured color, and visual scores for breech and body wrinkle. Whole carcass measures included HCW, dressing percentage (DP), and various measures of fat depth and eye muscle dimensions. Carcass components were obtained by dissection, and lean meat yield (LMY) was predicted. Heritability estimates for whole carcass measures ranged from 0.12 ± 0.08 to 0.35 ± 0.10 and ranged from 0.17 ± 0.10 to 0.46 ± 0.10 for carcass dissection traits, with no evidence of important genotype × environment interactions. Genetic correlations indicated that selection for increased clean wool weight will result in reduced carcass fat (-0.17 to -0.34) and DP (-0.48 ± 0.15), with little effect on carcass muscle. Selection for lower fiber diameter will reduce HCW (-0.48 ± 0.15) as well as carcass fat (0.14 to 0.27) and muscle (0.21 to 0.50). There were high genetic correlations between live animal measures of fat and muscle depth and the carcass traits (generally greater than 0.5 in size). Selection to increase HCW (and DP) will result in sheep with fewer wrinkles on the body (-0.57 ± 0.10) and barer breeches (-0.74 ± 0.12, favorable), with minor deterioration in scoured wool color (reduced brightness and increased yellowness). Selection for reduced fat will also result in sheep with fewer body wrinkles (-0.42 to -0.79). Increasing LMY in Merinos through selection would result in a large reduction in carcass fat and DP (-0.66 to -0.84), with a smaller increase in carcass muscle and some increase in wool weight and wrinkles. Although no major antagonisms are apparent between the wool and carcass traits, developing selection indexes for dual-purpose wool and meat breeding objectives will require accurate estimates of genetic parameters to ensure that unfavorable relationships are suitably considered. The findings will aid development of dual-purpose wool and meat breeding objectives.

The use of oxidative stress biomarkers in live animals (in vivo) to predict meat quality deterioration postmortem (in vitro) caused by changes in muscle biochemical components.

This study was conducted to determine whether circulating concentrations of blood isoprostanes can be used as an effective biomarker in lambs to predict degradation of color and/or lipid stability in meat. Lambs ( = 84) were fed diets of either lucerne pasture, annual ryegrass pasture, a commercial feedlot pellet, or a combination of annual ryegrass and feedlot pellet for 8 wk, including a 2-wk adaptation period. Blood isoprostane concentration at wk 0, 4, 6 or 8 of feeding was determined. Blood isoprostane concentration for each animal was then correlated with muscle biochemical components that impact color and/or lipid oxidative status during retail display. This included lipid oxidation levels in muscle assessed by thiobarbituric acid reactive substances and meat redness determined by a HunterLab colorimetric spectrometer. Lambs that consumed the commercial feedlot pellet had a lower muscle vitamin E level (< 0.01) and a greater level of -6 PUFA ( < 0.001) compared with lambs finished on annual ryegrass or lucerne. Lipid oxidation levels were greatest for lambs finished on the feedlot ration, lowest in lambs finished on the ryegrass diet, and intermediate for lambs finished on lucerne and ryegrass-feedlot combination ( < 0.01). After 8 wk of feeding, blood isoprostane concentration was positively correlated with lipid oxidation of meat displayed for 72 h in simulated retail conditions ( < 0.01). There was a negative linear relationship between isoprostane concentration and muscle vitamin E concentration ( = 0.07), lipid oxidation and muscle vitamin E concentration ( < 0.01) but a positive linear relationship between isoprostane concentration and muscle -6 PUFA ( < 0.001) or lipid oxidation and muscle -6 PUFA concentration ( < 0.001). Blood isoprostane concentration and lipid oxidation in meat were influenced by muscle vitamin E and -6 PUFA but not by -3 PUFA. There was no significant relationship observed between blood isoprostane concentration at 0, 4, 6 or 8 wk feeding vs. overall meat color (redness of meat) at 0 and 72 h of display, stored under simulated retail conditions. The results indicate that circulating blood isoprostane concentration can be a useful tool to predict the oxidative status of postmortem meat. Future work will examine the impact of this relationship on meat flavor/aroma deterioration post farm.

Meat science from 1976: A history of the journal.

The journal Meat Science was first published in 1976/77 and it initially comprised 4 issues per year. The first issue contained 4 papers and the first volume (4 issues) contained 27 articles, a mixture of papers and research notes. Its growth/popularity increased, and it has continued to thrive and in 2016 of the 1010 papers processed 292 were accepted. Over 90% of the papers published in the first volume were concerned with muscle biochemistry/meat properties. During the last years of the 20th century, meat products and their properties became a far larger proportion of the submissions as did those concerned with nutrition and safety. More recently there has been a resurgence of papers concerned with meat quality. Over the last 40years, the journal has reported on the major developments in meat science research and this paper will discuss both the history of the journal, and aspects of meat research as reflected in its publications. Possible future research trends are also discussed.

Retail colour stability of lamb meat is influenced by breed type, muscle, packaging and iron concentration.

The longissmus lumborum (LL) and semimembranosus (SM) muscles from 391 lamb carcasses, derived from various breed types, were used to investigate the effect of animal/muscle factors, packaging type [over-wrap (OW) or high oxygen modified atmosphere packaging (MAPO2)] and duration of display on redness of meat during simulated retail display. Using statistical models the time required (in days) for redness to reach a threshold value of 3.5 (below this is unacceptable) was predicted. High levels of iron in the SM, but not LL, reduced the time for redness to reach 3.5 by 2-2.6days in MAPO2 and 0.5-0.8days in OW. The greater the proportion of Merino breed type, the shorter was the time for redness to reach the value of 3.5, an effect consistent across muscles and packaging types. In summary, breed type, packaging format, muscle and muscle iron levels had a significant impact on colour stability of sheep meat in oxygen-available packaging systems.

The combined effects of grain supplementation and tenderstretching on alpaca (Vicugna pacos) meat quality.

This study investigated the effects of feeding a mixed grain supplement and tenderstretching (TS) alpaca carcasses on meat quality. A total of 56 castrated 24month old alpacas were divided into two treatments (pasture-only, and pasture plus supplementation). Supplemented groups were fed a mixed grain ration in addition to ad lib pasture for 10weeks. Animals were slaughtered across two kill days (n=28). One half of each carcass was suspended by the pelvis (TS) prior to chilling, and the other half was Achilles tendon hung (AH). After 24h, muscles were removed and aged for 10 and 25d. TS significantly increased sarcomere length and reduced shear force and cooking loss in the m. semimembranosus. This trend was not observed in other muscles including the m. longissimus thoracis et lumborum (LL) and m. psoas major. Ageing period resulted in a marginal improvement in LL tenderness. There is clear evidence that TS improves tenderness in the hindquarter of alpacas.

The impact of gender and age on the nutritional parameters of alpaca (Vicugna pacos) meat, colour stability and fat traits.

Meat quality parameters for 50 huacaya alpacas, representing three age groups (18, 24 and 36months) and two genders (females and castrated males) were studied. Prior to chilling, samples of m. longissimus thoracis et lumborum (LL) were taken to determine isocitrate dehydrogenase activity and glycogen concentration, and further meat quality samples were taken after 24h. Alpaca meat has low levels (<1%) of intramuscular fat in the LL, m. semimembranosus and m. biceps femoris, but the level in the LL increases with animal age, with levels of desirable polyunsaturated fatty acids (PUFA) ranging from 96.3 to 136.4mg/100g. Lipid oxidisation post retail display ranged from 1.27 to 1.96MDA/kg meat. Colour stability testing indicated alpaca meat was relatively stable during retail display with day of display having no significant effect on lightness (L*), or the 630nm/580nm ratio. These results may relate to the high proportion (76%) of glycolytic and type IIX muscle fibres in LL.

Application of small angle X-ray scattering synchrotron technology for measuring ovine meat quality.

A small angle X-ray scattering (SAXS) synchrotron was used to evaluate 100 ovine m. longissimus lumborum, representing lamb (n=50) and sheep (n=50). The diffraction of X-rays gives information on muscle myofibril structure and fat content. The linear relationships between SAXS measures with measures such as, shear force, intramuscular fat content (IMF) and collagen content/solubility, were investigated. A relationship was found between the d-spacing of the actin/myosin fibril spacing (SAX1 and SAX2) and the cross sectional area of the rhombohedral unit cell (Cell area) and shear force after 1 and 5day ageing. There was a positive relationship between IMF and a SAXS Fat area measure. There was a muscle site effect on SAX1, SAX2 and Cell area, with the cranial site having a larger distance between myofibrils. The potential of SAXS as a powerful research tool to determine not only the structural components of ovine tenderness, but also the fat content related to IMF is evident.

Optimum number of technical replicates for the measurement of compression of lamb meat.

Up to six (average 4.63) replicate compression values were collected on cooked m. semimembranosus of lambs that had been raised at six sites across southern Australia (n=1817). Measurements on each sample were made with one of two Lloyd Texture analyser machines, with each machine having a 0.63 cm diameter plunger. Based on a log normal model with common variance on the log scale for within sample replicate results, estimates of the within sample variability of compression values were obtained, resulting in a quality control procedure for compression testing based on the coefficient of variation.

Effect of electrical stimulation and ageing period on alpaca (Vicugna pacos) meat and eating quality.

This study investigated the effects of using medium voltage (~300 V) electrical stimulation (ES) and ageing on alpaca meat. A total of 50 huacaya alpacas were distributed across three age groups (18, 24 and 36 months) and two genders (females and castrated males). At 24h post mortem the m. longissimus thoracis et lumborum (LL) and m. semimembranosus (SM) muscles were removed and aged for either 5 or 10 days. In comparison to non-ES samples, ES significantly reduced: LL purge values by 3.0% and LL shear force (SF) at 5 and 10 days (by 21.6N and ageing further reduced tenderness by 6.6N), and SM SF by 5.8 N with significant age effects observed in both ES and non-ES SM samples, such that SF increased by 0.53 N with each month increase in animal age. Consumers rated ES samples higher on tenderness, juiciness, flavour and overall rating. ES and ageing of alpaca carcasses are recommended.

Carcass traits and saleable meat yield of alpacas (Vicugna pacos) in Australia.

Carcass traits and saleable meat yield (SMY) of female and castrated male alpacas in Australia at 18, 24 and 36 months of age were investigated. Fifty huacaya alpacas, evenly distributed across 14, 20, 32 month ages and two genders, were grazed on coastal summer pastures for four months. Dressing percentage and carcass length were collected at slaughter. At 24h post-mortem the carcasses were prepared into four SMY combinations. Thirty six month animals had heavier hot carcass weights (33.7 ± 1 kg) and longer carcasses (81.2 ± 0.7 cm) as expected. The percentage of total carcass bone (17.5 ± 0.2%), fat trim (1.4 ± 0.1%) and meat trim (7.8 ± 0.4%) was assessed as a proportion of cold carcass weight. The proportion of fat increased and bone decreased with age. Females had more trim than males. SMY decreased in females and increased in males with age across all combinations suggesting that males are preferable for meat production.

A comparison of technical replicate (cuts) effect on lamb Warner-Bratzler shear force measurement precision.

The Warner-Bratzler shear force (WBSF) of 335 lamb m. longissimus lumborum (LL) caudal and cranial ends was measured to examine and simulate the effect of replicate number (r: 1-8) on the precision of mean WBSF estimates and to compare LL caudal and cranial end WBSF means. All LL were sourced from two experimental flocks as part of the Information Nucleus slaughter programme (CRC for Sheep Industry Innovation) and analysed using a Lloyd Texture analyser with a Warner-Bratzler blade attachment. WBSF data were natural logarithm (ln) transformed before statistical analysis. Mean ln(WBSF) precision improved as r increased; however the practical implications support an r equal to 6, as precision improves only marginally with additional replicates. Increasing LL sample replication results in better ln(WBSF) precision compared with increasing r, provided that sample replicates are removed from the same LL end. Cranial end mean WBSF was 11.2 ± 1.3% higher than the caudal end.

The impact of supplementing lambs with algae on growth, meat traits and oxidative status.

The current study examined the effect of supplementing lambs with algae. Forty, three month old lambs were allocated to receive a control ration based on oats and lupins (n=20) or the control ration with DHA-Gold™ algae (~2% of the ration, n=20). These lambs came from dams previously fed a ration based on either silage (high in omega-3) or oats and cottonseed meal (OCSM: high in omega-6) at joining (dam nutrition, DN). Lamb performance, carcase weight and GR fat content were not affected by treatment diet (control vs algae) or DN (silage vs OSCM). Health claimable omega-3 fatty acids (EPA+DHA) were significantly greater in the LL of lambs fed algae (125±6mg/100g meat) compared to those not fed algae (43±6mg/100g meat) and this effect was mediated by DN. Supplementing with algae high in DHA provides a means of improving an aspect of the health status of lamb meat.

Comparison of rankings for lean meat based on results from a CT scanner and a video image analysis system.

Coopworth cross lambs born over three years were examined in this study. Differences between two machines; a computer tomography (CT) scanner and a VIAScan® system for the estimation of carcase lean weight in lamb carcases was examined. The CT scanner provided a significantly higher estimate of carcase lean. The rank correlation (0.84) between the CT scanner and the VIAScan® system for the prediction of carcase lean was significant, but there was a different ranking for carcase lean depending on which machine was used. This has important ramifications for the use of VIAScan® data in the New Zealand Sheep Improvement Ltd genetic programme.

Effect of genotype, gender and age on sheep meat quality and a case study illustrating integration of knowledge.

Subtle breed differences exist for meat quality traits and the Merino does stand out, although many comparisons are confounded by production site or lack of processing intervention. Despite this, the Merino does seem to have a propensity to produce meat with a higher pH and reduced colour stability under extended ageing. Use of the Merino in a crossbreeding system not only provides benefits from hybrid vigour, but also overcomes the meat quality constraints of pure Merinos. Genetic evaluation for lamb production has enabled impressive genetic gains, but an overemphasis on lean meat production has had to be addressed to counter adverse effects on meat quality traits like eating quality. In this regard, the development of genomic selection has provided a methodology for accurate prediction of genetic merit and applying balanced breeding objectives. The potential for negative meat quality effects has stemmed adoption of non-castration approaches, but ensuring that lamb is young when slaughtered does provide brand integrity.