The pre-requisites for nutritional management of dairy cows are information about how much feed is being consumed as well as the nutrients that are being derived from that feed. Studies of feed intake and nutrient supply have been limited by difficult experimental techniques, particularly with grazing animals. The models derived from much earlier work are of only general applicability and there is a need for more site-specific information in order to benefit further from conceptual advances.
We have adopted a different approach to studying herbage intake and nutrient supply, using less-invasive approaches as well as techniques that monitor more accessible aspects of these processes, such as jaw movements. These techniques have a major advantage, in addition to their value as research tools, because they could translate directly into commercial applications in on-farm monitoring. The use of diagnostics and behavioural recording is well explored in relation to health monitoring; here we argue for its potential to advance the application of knowledge about grazing and nutrition. We will illustrate this approach using our experiences in measuring grazing behaviour, using IGER behaviour recorders and assessing rumen function, using a series of non-invasive techniques.
The IGER grazing behaviour recorder allows us to record jaw movements and hence grazing and ruminating time and bite dynamics. It also allows the recording of steps and is now being developed to incorporate non-invasive rumen state sensors. It has made a major contribution to our understanding of the foraging strategies of grazing animals and their effect on herbage intake. This technology has the potential to be developed for on-farm monitoring of foraging behaviour providing valuable inputs to the prediction of herbage intake, in decision support systems for grazing.
The introduction of concept of protein degradation and microbial synthesis in the rumen are significant advances in protein rationing schemes. However, real progress has been limited because the lack of consistent experimental results means that models have little relevance to specific farm situations. We foresee considerable opportunities to monitor products of rumen degradation and synthesis that appear in milk (e.g. odd-chain fatty acids) or breath (e.g. sulphides).
Taken together these technologies open the possibilities of an entirely new approach to nutritional management of dairy cows, with site-specific recommendations based on information gathered using new sensors that are incorporated into computerised feeding equipment and milking parlours.