Southern Multi-Breed (SMB) is a landmark five-year project, collecting high-quality phenotypes and genotypes on animals from six breeds, managed in multi-breed groups at five NSW Department of Primary Industries research herds. Data collected will enhance genetic evaluations and facilitate the development of a multi-breed genetic evaluation. The project design focussed on selecting foundation cows and sires to represent the breed's populations. This paper aimed to quantify the linkage between the genetics represented in the SMB project and the breed populations. Within each breed, the average relationship coefficient of each animal to SMB foundation cows and sires and all animals in the breed was calculated and plotted to form a visual metric of the linkage. Regression slopes between 1.11 and 1.37 and correlations between 0.86 and 0.99 were calculated from the plots. The visual and quantitative metrics indicated that the genetics in SMB represent the breed populations. Therefore, the reference data collected as part of SMB will benefit the broader industry.

Most honey produced globally is classed as table honey, for direct consumption, as distinct from higher value medicinal grade honeys. Economic value of honey was based on domestic table honey price in AU$ derived from Australia (AU) and the United States (US), from 2010-2021 and sourced from AU honey processors and the US Department of Agriculture. For 2021, average AU and US domestic honey values were AU$5.70 and AU$6.53 per kg respectively. Domestic price slopes for 2010-2021 were similar for AU and US at an increase of AU$0.28 per year. Characteristics for honey production (HP) per hive per year were collated from four manuscripts and three AU datasets, presenting a substantial range of means (8.5 to 123.3 kg), and standard deviations (2.6 to 42.8 kg). Variability in HP between studies is attributed to differences in phenotyping, genotype, environment and production scale.

Background There can be variation between animals in how stable their genetic merit is across different environments due to genotype-by-environment (G×E) interactions. This variation could be used in breeding programs to select robust genotypes that combine high overall performance with stable genetic ranking across environments. There have been few attempts to validate breeding values for robustness in livestock, although this is a necessary step towards their implementation in selection decisions. The objective of this study was to validate breeding values for the robustness of body weight across different growth environments that were estimated using reaction norm models in sheep data.

Results Using threefold cross-validation for the progeny of 337 sires, the average correlation between single-step breeding values for the reaction norm slope and the realised robustness of progeny across different growth environments was 0.21. The correlation between breeding values for the reaction slope estimated independently in two different datasets linked by common sires was close to the expected correlation based on theory.

Conclusions Slope estimated breeding values (EBV) obtained using reaction norm models were predictive of the phenotypic robustness of progeny across different environments and were consistent for sires with progeny in two different datasets. Selection based on reaction norm EBV could be used to increase the robustness of a population to environmental variation.

This study investigated the genetic relationship between eye muscle width and depth recorded via ultrasound on live animals and on carcases in two populations of Australian and New Zealand sheep. Genetic correlations between ultrasound and carcase muscle dimensions were estimated within populations. Carcase eye muscle dimensions have sufficient genetic variation to be included in sheep breeding programs. Genetic correlations between carcase eye muscle depth (CEMD) and width (CEMW), and between CEMW and ultrasound eye muscle depth (PEMD) in Australian sheep were lower than expected. On the other hand, high genetic correlations were observed between ultrasound depth and width recorded in different ages on New Zealand Merinos. These differences indicate further research about CEMW is required and the implications of current selection practises has on carcase eye muscle dimensions.

The LAMPLAN – Terminal and Maternal analysis are large and contain multiple breeds. Over the last 20 years there has been an increase in cross breeding in seedstock flocks and thus the number of composite animals in these analyses, especially in the Maternal analysis and an overall reduction in the number of breed pure animals. The increase in crossbred animals will require some development to ensure that breed and heterosis effects are being modelled accurately. Further use and reporting of breed composition via genomics and pedigree methods should be considered. However, composite animals provide the comparisons needed for an accurate multibreed LAMBPLAN analysis allowing selection of animals across breeds for the industries diverse needs.

The capacity to measure and select livestock that are more resilient to environmental fluctuation is of increasing importance amidst climate change, labour shortages and increasing production demand. Currently, however, there is no consensus on how to quantify resilience, particularly in extensive sheep populations. In this study, we explored the ability to derive resilience indicator traits from fibre diameter variation measured longitudinally (5 mm increments) along the wool staple. Fibre diameter varies in relation to the supply of nutrients to the wool follicles and thereby provides a stable archive of the animal's physiological status across the preceding wool growth period. From this fibre diameter variation, ways to detect and characterise an animal's ability to withstand or be minimally affected by its environment were explored. The heritability estimates of these traits were shown to be low to moderate (0.10 to 0.31), indicating that genetic variation exists for fibre diameter variation measured along the wool staple which may be interpreted as a measure of resilience. The inclusion of such measures in sheep breeding programs has the potential to improve the resilience of sheep to environmental challenges, which may have positive implications for sheep enterprise profitability, health and welfare.

This paper investigates the ability of different linear mixed models to estimate the heritability of sex determination in a sub-set of the Australian Merino population. The dataset used was from Centre Plus Merinos in central-west New South Wales with 25 plus years of full pedigree collection and over 20,000 lambing events where the sex of the progeny were recorded. This study used sex of a lamb as a trait, (i.e. zero phenotype for female and one phenotype for male). We observed a significant, yet normal, amount of phenotypic variation in the sex ratio of progeny for dams, sires, maternal grand sires and maternal grand dams. However, no model was able to estimate significant genetic variation in sex determination and failed to return a heritability above 0.01. Consequently, it can be concluded within this dataset that it would not be possible to select to alter sex determination in Merinos.