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Context: In most pasture-based herds in Australia, supplementation with concentrates is normally a flat rate, with quantities determined by average cow requirements, rather than individual-cow requirements. Comparisons between flat rate and individual feeding rarely show advantages such as milk yield benefits for either. However, in pasture-based systems little is understood regarding milk production responses or levels of pasture substitution, when different groups of cows within the herd are fed concentrates at higher supplementation levels. Aims: To investigate the effect on milk yield, feeding time, and ruminating time, of two flat-rate supplementation levels of concentrate, fed over 8 months to 180 cows selected for one of three different parameters. Methods: Cohorts of cows were selected on contrasting differences for either milk production at the start of lactation, bodyweight, or genotype. Each cohort was divided into two balanced groups receiving either 2 or 6 kg DM/cow.day of concentrate, from approximately 12 days in milk onward. All cows remained part of the main milking herd (total herd size 320 spring-calving cows), with a similar opportunity for all cows to graze pasture or feed on supplemented grass silage during periods of pasture shortage. Milk yield was recorded at each milking and feeding behaviour continuously recorded by MooMonitor+ collars. Results were analysed for three seasonal periods of 10, 12 and 10 weeks (P1, P2 and P3 respectively) commencing in spring. Key results: Mean marginal milk response (L milk per 1 kg DM extra of concentrate) over the trial period was 0.88 L, increasing from 0.71 L in P1, to 0.92 L in P2 and 1.03 L in P3. The high-concentrate cohorts recorded reduced feeding time per day of 37 min overall (46, 35 and 29 min for P1, P2 and P3 respectively). Significant differences were found for milk yield and feeding time between several contrasting cohorts. The lowest marginal milk response was for cross-breed cows in P1 with 0.18 L and feeding reduced by 65 min/cow.day, with the contrasting cohort of Friesian cows at a larger marginal response of 0.94 L and smaller feeding time reduction of 32 min/cow.day. Conclusions: The differences among cohorts demonstrated potential for targeted concentrate feeding to specific groups of cows that respond differently in marginal milk yield and grazing behaviour. Implications: When a significant change is made in strategic amounts of concentrate feeding, the impact not only on marginal milk response should be considered, but also on pasture intake. In pasture-based dairy systems little is understood regarding production responses or pasture substitution with different amounts of concentrates fed. Cohorts of cows were selected on contrasting differences for three parameters and fed concentrate at two flat-rate levels, while milk yield and feeding time were monitored. Contrasting responses were found between cross-breed and Friesian cows. Differences between cohorts demonstrated potential for targeted concentrate feeding to contrasting cohorts of cows, and the need to consider both marginal milk response and pasture intake. This article belongs to the Collection ADSS 2022: A Changing Climate for Dairy Science. [ABSTRACT FROM AUTHOR]

Forage management underpins the viability of pastoral dairy systems. This review investigated recent developments in forage research and their potential to enable pastoral dairy systems to meet the challenges that will be faced over the next 10 years. Grazing management, complementary forages, pasture diversity, fertiliser use, chemical restriction, irrigation management and pasture breeding are considered. None of these areas of research are looking to increase production directly through increased inputs, but, rather, they aim to lift maximum potential production, defend against production decline or improve the efficiency of the resource base and inputs. Technology approaches consistently focus on improving efficiency, while genetic improvement or the use of complementary forages and species diversity aim to lift production. These approaches do not require additional labour to implement, but many will require an increase in skill level. Only a few areas will help address animal welfare (e.g. the use of selected complementary forages and novel endophytes) and only complementary forages will help address increased competition from non-dairy alternatives, by positively influencing the properties of milk. Overall, the diversity of activity and potential effects will provide managers of pastoral dairy systems with the best tools to respond to the production and environmental challenges they face over the next 10 years. Forage management underpins the success of pastoral dairy industries. Recent dairy forage research was reviewed through a production and input loss frontier framework along with their potential impacts on competition from non-dairy alternatives, labour and animal welfare challenges. The diversity of approaches to modifying both the production and input loss frontiers will provide the tools for pasture managers to meet future production and environmental challenges. [ABSTRACT FROM AUTHOR]