Some challenges and opportunities for grazing dairy cows on temperate pastures

Abstract

Grazing plays an important role in milk production in most regions of the world. In this review, some challenges to the grazing cow are discussed together with opportunities for future improvement. We focus on daily feed intake, efficiency of pasture utilization, output of milk per head, environmental impact of grazing and the nutritional quality to humans of milk produced from dairy cows in contrasting production systems. Challenges are discussed in the context of a trend towards increased size of individual herds and include limited and variable levels of daily herbage consumption, lower levels of milk output per cow, excessive excretion of nitrogenous compounds and requirements for minimal periods of grazing regardless of production system.A major challenge is to engage more farmers in making appropriate adjustments to their grazing management. In relation to product quality, the main challenge is to demonstrate enhanced nutritional/processing benefits of milk from grazed cows.Opportunities include more accurate diet formulations, supplementation of grazed pasture to match macro-and micronutrient supply with animal requirement and plant breeding. The application of robotics and artificial intelligence to pasture management will assist in matching daily supply to animal requirement. Wider consumer recognition of the perceived enhanced nutritional value of milk from grazed cows, together with greater appreciation of the animal health, welfare and behavioural benefits of grazing should contribute to the future sustainability of demand for milk from dairy cows on pasture. K E Y W O R D Sgrazed pasture, grazing management, herbage intake, milk production, milk quality, nitrogen use efficiency Highlights• Grazing plays a central role in the nutrition of dairy cows in many regions of the world.• Challenges to efficient management of grazed pastures include variable herbage supply and low herbage intake, which limit milk output per head.• Opportunities for improved efficiency include more accurate diet formulation, breeding superior plant cultivars to improve ruminal efficiency and enhance product nutritional quality, application of robotics, sensors and artificial intelligence to improve grazing management and pasture utilization, and wider consumer recognition of the perceived enhanced value of milk from grazed cows.TA B L E 1 Average size of dairy herd, average annual milk yield per cow and average annual output of milk per herd in New Zealand,

The Mineral Composition of Wild-Type and Cultivated Varieties of Pasture Species

“…Due to the wide variety of minerals required by livestock, as well as other nutrients such as vitamins, protein, fibre and metabolizable energy, it is unlikely that a single pasture species will provide livestock with a complete diet [8]. Improved grasslands tend to have low plant diversity, and Lolium perenne, Trifolium pratense and Trifolium repens typically provide the basis of most swards, with a focus on maintaining sufficient DM yield and protein production over a grazing season, or providing sufficient early season growth for a silage cut [9]. These species-poor plant communities bear little resemblance to the natural vegetation that the ancestors of our modern livestock breeds evolved to graze.…”

Milk Production, Milk Quality, and Behaviour of Dairy Cows Grazing on Swards with Low and High Water-Soluble Carbohydrates Content in Autumn: A Pilot Trial

“…Herbage allowance is one of the most important sward characteristics that influence herbage DMI [32]. On average, daily HA for both swards in the present study exceeded 30 kg DM/cow.…”

Increasing Grazing in Dairy Cow Milk Production Systems in Europe

“…Challenges include infrastructural constraints such as facilities, farm fragmentation, farm size and mechanization, and cultural constraints such as cow type, pasture management skills, government policy (EU and local) and milk price. Grazing systems are associated with opportunities for greater global sustainability, increased product quality, improved animal welfare, and increased labour efficiency [8].…”