AgResearch,Crown Research Institutes

Objectives: To test whether Scandinavian Red (SR) sires improve udder health (somatic cell score; SCS) in New Zealand crossbred dairy cows without compromising milk solids yield. Materials and Methods: Herd-test records (one test day per cow) from six pasture-based New Zealand herds were analyzed (n = 5,294). All cows were daughters of Friesian x Jersey dams and were sired by Friesian (F), Jersey (J), Friesian × Jersey (F × J), or SR bulls. SCS was calculated as ln (SCC/1,000). Linear models estimated sire-breed effects on SCS, adjusting for herd, cow age group, days in milk (linear and quadratic), and milk solids (fat + protein, kg/day). Tukey-adjusted comparisons were used. Results: Sire breed significantly affected SCS (p = 0.004). SR-sired cows had the lowest adjusted mean SCS and were significantly lower than F- and J-sired cows; F × J-sired cows were intermediate. Milk solids (kg/day) yield did not differ by sire breed (p = 0.12). Older cows, early/late lactation, and herds were associated with higher SCS. Conclusions: Under pasture-based New Zealand conditions, using SR sires on Friesian x Jersey dams was associated with improved udder health (lower SCS) without reducing milk solids yield, supporting SR genetics as a practical option to reduce mastitis risk and antimicrobial use.

Genotyping by sequencing (GBS) is widely employed in aquaculture selective breeding programs to acquire SNP genotypes for various applications, including pedigree reconstruction, GWAS, and in the estimation of genetic parameters, genomic relationships and breeding values. Because sequencing libraries encompass all DNA present in fin-clip tissue, they also recover the non-host metagenomic fraction, including pathogens. We leveraged this property to survey for the presence of scale-drop disease virus (SDDV), responsible for 40-90 % mortality in farmed barramundi, while simultaneously genotyping the host. Raw reads from 4484 fish of four commercial cohorts (2239 moribund, 2245 asymptomatic) were aligned to the SDDV reference genome, and viral reads were normalised as reads per million (RPM) per individual. SDDV prevalence and load were tightly associated with clinical status: 88.9 % of moribund fish carried SDDV at 21.8 f 0.6 RPM, whereas only 0.2 % of healthy fish were positive with 0.002 f 0.001 RPM. Independent validation by quantitative PCR on fin and spleen from a nested subset of 172 fish (81 moribund, 91 healthy) yielded viral copy numbers strongly correlated with ddRADseq RPM (Spearman's rho = 0.84 for fin; rho = 0.76 for spleen; both P < 0.0001). Viral load was consistently higher in fin (mean 281 f 45 copies ng-1 DNA) than spleen (147 f 32 copies ng-1), corroborating the suitability of non-lethal fin tissue for surveillance. Prevalence and load distributions were homogeneous across cohorts, and no qPCRpositive individuals escaped detection by ddRADseq. These findings show that routine ddRADseq datasets in barramundi can also be repurposed into a sensitive epidemiological assay that unites SDDV monitoring with genomic improvement. Further, these findings suggest that breeding programs generating large ddRADseq GBS datasets may also serve pathogen surveillance purposes where the target pathogen infects the host genotyped tissue.

Deforestation and forest degradation have escalated in tropical dry forests in recent decades, depleting biodiversity and carbon stocks. This is particularly meaningful for the Argentinean Dry Chaco, a deforestation frontier where silvopastoral systems could expand on more than 18 million hectares. Here, we evaluate long term forest and woody carbon dynamics of two silvopastoral systems: Forest management integrated with livestock (herein MBGI) and traditional silvopastoral (TSP), and compared these with undisturbed primary native forests. To do so, we developed a model using systems dynamics methodology, literature review, and expert elicitation, and then parameterized it with over 570 field sampling sites collected across the region. Our results show that in the long-term (i.e., 90 years), forest management integrated with livestock (MBGI) retained 53% more woody carbon than TSP, but 28% less than the undisturbed primary native forest. Moreover, MBGI maintained forest structure over time, with the shrub layer holding 27% of the total carbon stock. In the long term simulation, MBGI showed a positive carbon sequestration rate, whereas TSP showed a negative one. Overall, we provide a robust evaluation of forest population and carbon dynamics for alternative silvopastoral systems in the Dry Chaco region that could be adapted to other tropical dry forests. Our results highlight the medium- to long-term sustainability of semi-intensive silvopastoral systems which sustain forest attributes while allowing for the expansion of agricultural production. This is crucial for deforestation frontiers in tropical dry forests, where finding alternatives to deforestation is essential.

CONTEXT: Pig farming significantly impacts environmental and human health due to nitrogen (N) losses, particularly ammonia (NH3) emissions, especially in regions with high concentration of pig production. In China, national policies regulate the spatial distribution of pig farming, leading to regional variations that influence product distribution and environmental outcomes. However, our understanding of how regional policy responses affect N emissions and the associated socioeconomic costs of pig production remains limited.OBJECTIVES: This study aims to analyze changes in the spatial distribution of N emissions and the associated socioeconomic costs resulting from provincial responses to central pig production policies. Guangdong and Zhejiang, as the main pig marketing areas in China, and Hebei, as a major pig-production area, were selected to represent different regional responses. These provinces adopted distinct strategies to maintain production while mitigating environmental impacts. METHODS: The study integrates consistent county-level pig production data from 2000 to 2021 with the NUFER (nutrient fluxes in food chains, environment, and resource use)-animal model. Spatial and temporal patterns of N emissions were analyzed using geostatistical methods, and socioeconomic costs were quantified based on environmental health impact assessments. The policy-driven changes in pig production distribution were eval-uated to assess their effectiveness in mitigating environmental impacts while maintaining production levels. RESULTS & CONCLUSIONS: Our findings reveal that Guangdong strategically relocated pig production from densely populated to less populated areas to maintain pork self-sufficiency, leading to a 15 % increase in so-cioeconomic costs. Zhejiang closed many pig farms and relocated others away from watercourses to protect water quality, reducing pig production by 60 % and NH3-related costs by 20 %. Hebei province maintained its pig production levels in densely populated areas to secure pork supplies for Beijing and other surrounding cities, which led to a 25 % increase in socioeconomic costs. These results highlight that despite strong central gover-nance, provinces in China respond differently to national regulations. Provincial spatial planning is more effective than uniform policies in balancing ecological preservation and agricultural productivity. SIGNIFICANCE: This study reveals how differentiated provincial responses to national policies have shaped spatial patterns of N emissions and their socioeconomic impacts. Future policies should build on strategies like Guangdong's intra-provincial relocation approach, which balanced production with ecological capacity. Gov-ernments should strengthen spatial planning tools and establish fiscal mechanisms that compensate regions bearing higher environmental burdens. These insights provide actionable guidance for designing regionally adaptive pig production policies in China and beyond.

Parasitoids are central to classical biological control, yet predicting their long-term effectiveness post release remains challenging. In Aotearoa New Zealand, three Microctonus (Hymenoptera: Braconidae) species have been used against pest weevils, but key aspects of their biology remain poorly understood. This is evident in postrelease decline of M. hyperodae efficacy and geographically variable nontarget impacts among M. aethiopoides strains. Such cases highlight knowledge gaps in host-searching behaviour, reproductive mode, adaptability to environmental conditions, and microbiome composition within parasitoids and hosts. We review studies, mainly on Hymenopteran parasitoids, focusing on key adaptive traits important in biocontrol: reproductive mode, olfaction, thermal tolerance, and symbiont interactions. Synthesising findings from host specificity, behavioural, and molecular analyses, we identify broader patterns and key gaps. While molecular research on Microctonus is limited, evidence from other systems shows trait-specific adaptive responses, with variation in olfactory sensitivity, reproductive strategies, and the microbiome interactions influencing host use success and potentially persistence. While field-level efficacy is often assessed, species-specific evaluation of life history traits under relevant environmental conditions is essential, followed by genomic and transcriptomic studies to reveal the molecular basis of adaptation. Integrating behavioural, molecular, microbiome, and ecological insights will be essential for optimising parasitoid releases and ensuring long-term biocontrol success in New Zealand.